diff options
Diffstat (limited to 'tools/apriori/apriori.c')
| -rw-r--r-- | tools/apriori/apriori.c | 2775 |
1 files changed, 0 insertions, 2775 deletions
diff --git a/tools/apriori/apriori.c b/tools/apriori/apriori.c deleted file mode 100644 index b827375..0000000 --- a/tools/apriori/apriori.c +++ /dev/null @@ -1,2775 +0,0 @@ -#include <stdio.h> -#include <stdlib.h> -#include <common.h> -#include <debug.h> -#include <libelf.h> -#include <libebl.h> -#ifdef ARM_SPECIFIC_HACKS - #include <libebl_arm.h> -#endif/*ARM_SPECIFIC_HACKS*/ -#include <elf.h> -#include <gelf.h> -#include <string.h> -#include <errno.h> -#include <string.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <fcntl.h> -#include <unistd.h> -#include <hash.h> -#include <apriori.h> -#include <source.h> -#include <tweak.h> -#include <rangesort.h> -#include <prelink_info.h> -#include <prelinkmap.h> -#include <libgen.h> - -#ifndef ADJUST_ELF -#error "ADJUST_ELF must be defined!" -#endif - -/* When this macro is defined, apriori sets to ZERO those relocation values for - which it canot find the appropriate referent. -*/ -#define PERMISSIVE -#define COPY_SECTION_DATA_BUFFER (0) -/* When this macro is set to a nonzero value, we replace calls to elf_strptr() - on the target ELF handle with code that extracts the strings directly from - the data buffers of that ELF handle. In this case, elf_strptr() does not - work as expected, as it tries to read the data buffer of the associated - string section directly from the file, and that buffer does not exist yet - in the file, since we haven't committed our changes yet. -*/ -#define ELF_STRPTR_IS_BROKEN (1) - -/* When the macro below is defined, apriori does not mark for removal those - relocation sections that it fully handles. Instead, apriori just sets their - sizes to zero. This is more for debugging than of any actual use. - - This macro is meaningful only when ADJUST_ELF!=0 -*/ -#define REMOVE_HANDLED_SECTIONS - -extern int verbose_flag; - -static source_t *sources = NULL; - -/* Retouch data is a very concise representation of the resolved relocations. - This data is used to randomize the location of prelinked libraries at - update time, on the device. - */ - -// We will store retouch entries into this buffer, then dump them at the -// end of the .so file before setup_prelink_info(). -#define RETOUCH_MAX_SIZE 600000 -static char *retouch_buf; -static unsigned int retouch_byte_cnt; -// Compression state. -static int32_t offs_prev; -static uint32_t cont_prev; - -#define false 0 -#define true 1 - -void retouch_init(void) { - offs_prev = 0; - cont_prev = 0; - retouch_byte_cnt = 0; - retouch_buf = malloc(RETOUCH_MAX_SIZE+12); - FAILIF(retouch_buf == NULL, - "Could not allocate %d bytes.\n", RETOUCH_MAX_SIZE+12); -} - -// -// We use three encoding schemes; this takes care of much of the redundancy -// inherent in lists of relocations: -// -// * two bytes, leading 1, 2b for d_offset ("s"), 13b for d_contents ("c") -// -// 76543210 76543210 -// 1ssccccc cccccccc -// -// * three bytes, leading 01, 2b for delta offset, 20b for delta contents -// -// 76543210 76543210 76543210 -// 01sscccc cccccccc cccccccc -// -// * eigth bytes, leading 00, 30b for offset, 32b for contents -// -// 76543210 76543210 76543210 76543210 -// 00ssssss ssssssss ssssssss ssssssss + 4 bytes contents -// -// NOTE 1: All deltas are w.r.t. the previous line in the list. -// NOTE 2: Two-bit ("ss") offsets mean: "00"=4, "01"=8, "10"=12, and "11"=16. -// NOTE 3: Delta contents are signed. To map back to a int32 we refill with 1s. -// NOTE 4: Special encoding for -1 offset. Extended back to 32b when decoded. -// - -void retouch_encode(int32_t offset, uint32_t contents) { - int64_t d_offs = offset-offs_prev; - int64_t d_cont = (int64_t)contents-(int64_t)cont_prev; - - uint8_t output[8]; - uint32_t output_size; - - if ((d_offs > 3) && - (d_offs % 4) == 0 && - (d_offs / 4) < 5 && - (d_cont < 4000) && - (d_cont > -4000)) { - // we can fit in 2 bytes - output[0] = - 0x80 | - (((d_offs/4)-1) << 5) | - (((uint64_t)d_cont & 0x1f00) >> 8); - output[1] = - ((uint64_t)d_cont & 0xff); - output_size = 2; - } else if ((d_offs > 3) && - (d_offs % 4) == 0 && - (d_offs / 4) < 5 && - (d_cont < 510000) && - (d_cont > -510000)) { - // fit in 3 bytes - output[0] = - 0x40 | - (((d_offs/4)-1) << 4) | - (((uint64_t)d_cont & 0xf0000) >> 16); - output[1] = - ((uint64_t)d_cont & 0xff00) >> 8; - output[2] = - ((uint64_t)d_cont & 0xff); - output_size = 3; - } else { - // fit in 8 bytes; we can't support files bigger than (1GB-1) - // with this encoding: no library is that big anyway.. - FAILIF(offset < -1 || offset > 0x3ffffffe, "Offset out of range.\n"); - output[0] = (offset & 0x3f000000) >> 24; - output[1] = (offset & 0xff0000) >> 16; - output[2] = (offset & 0xff00) >> 8; - output[3] = (offset & 0xff); - output[4] = (contents & 0xff000000) >> 24; - output[5] = (contents & 0xff0000) >> 16; - output[6] = (contents & 0xff00) >> 8; - output[7] = (contents & 0xff); - output_size = 8; - } - - // If this happens, the retouch buffer size can be bumped up. - // Currently, the largest case is libwebcore, at about 250K. - FAILIF((retouch_byte_cnt+output_size) > RETOUCH_MAX_SIZE, - "About to overflow retouch buffer.\n"); - - memcpy(retouch_buf+retouch_byte_cnt, output, output_size); - retouch_byte_cnt += output_size; - - offs_prev = offset; - cont_prev = contents; -} - -void retouch_dump(const char *fname, int elf_little, - unsigned int retouch_byte_cnt, char *retouch_buf) { - int fd = open(fname, O_WRONLY); - FAILIF(fd < 0, - "open(%s, O_WRONLY): %s (%d)\n" , - fname, strerror(errno), errno); - off_t sz = lseek(fd, 0, SEEK_END); - FAILIF(sz == (off_t)-1, - "lseek(%d, 0, SEEK_END): %s (%d)!\n", - fd, strerror(errno), errno); - - // The retouch blob ends with "RETOUCH XXXX", where XXXX is the 4-byte - // size of the retouch blob, in target endianness. - strncpy(retouch_buf+retouch_byte_cnt, "RETOUCH ", 8); - if (elf_little ^ is_host_little()) { - *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) = - switch_endianness(retouch_byte_cnt); - } else { - *(unsigned int *)(retouch_buf+retouch_byte_cnt+8) = - retouch_byte_cnt; - } - - int num_written = write(fd, retouch_buf, retouch_byte_cnt+12); - FAILIF(num_written < 0, - "write(%d, &info, sizeof(info)): %s (%d)\n", - fd, strerror(errno), errno); - FAILIF((retouch_byte_cnt+12) != num_written, - "Could not write %d bytes as expected (wrote %d bytes instead)!\n", - retouch_byte_cnt, num_written); - FAILIF(close(fd) < 0, "close(%d): %s (%d)!\n", fd, strerror(errno), errno); -} - -/* End of retouch code. - */ - -#if defined(DEBUG) && 0 - -static void print_shdr(source_t *source, Elf_Scn *scn) -{ - GElf_Shdr shdr_mem, *shdr; - shdr = gelf_getshdr(scn, &shdr_mem); - Elf_Data *data = elf_getdata(scn, NULL); - INFO("\t%02d: data = %p, hdr = { offset = %8lld, size = %lld }, " - "data->d_buf = %p data->d_off = %lld, data->d_size = %d\n", - elf_ndxscn(scn), - data, - shdr->sh_offset, shdr->sh_size, - data->d_buf, data->d_off, data->d_size); -} - -static void print_shdr_idx(source_t *source, Elf *elf, int idx) -{ - print_shdr(source, elf_getscn(elf, idx)); -} - -static void print_shdrs(source_t *source) { - Elf_Scn *scn = NULL; - INFO("section offset dump for new ELF\n"); - while ((scn = elf_nextscn (source->elf, scn)) != NULL) - print_shdr(source, scn); - - INFO("\nsection offset dump for original ELF\n"); - while ((scn = elf_nextscn (source->oldelf, scn)) != NULL) - print_shdr(source, scn); - -#if 0 - { - INFO("section offset dump for new ELF\n"); - int i = 0; - for (i = 0; i < source->shnum; i++) { - scn = elf_getscn(source->elf, i); - print_shdr(source, scn); - } - } -#endif -} - -#endif /* DEBUG */ - -static char * find_file(const char *libname, - char **lib_lookup_dirs, - int num_lib_lookup_dirs); - -static inline source_t* find_source(const char *name, - char **lib_lookup_dirs, - int num_lib_lookup_dirs) { - char *full = find_file(name, lib_lookup_dirs, num_lib_lookup_dirs); - if (full) { - source_t *trav = sources; - while (trav) { - if (!strcmp(trav->name, full)) - break; - trav = trav->next; - } - free(full); - return trav; - } - return NULL; -} - -static inline void add_to_sources(source_t *src) { - src->next = sources; - sources = src; -} - -static void handle_range_error(range_error_t err, - range_t *left, range_t *right) { - switch (err) { - case ERROR_CONTAINS: - ERROR("ERROR: section (%lld, %lld bytes) contains " - "section (%lld, %lld bytes)\n", - left->start, left->length, - right->start, right->length); - break; - case ERROR_OVERLAPS: - ERROR("ERROR: Section (%lld, %lld bytes) intersects " - "section (%lld, %lld bytes)\n", - left->start, left->length, - right->start, right->length); - break; - default: - ASSERT(!"Unknown range error code!"); - } - - FAILIF(1, "Range error.\n"); -} - -static void create_elf_sections(source_t *source, Elf *elf) -{ - INFO("Creating new ELF sections.\n"); - ASSERT(elf == NULL || source->elf == NULL || source->elf == elf); - if (elf == NULL) { - ASSERT(source->elf != NULL); - elf = source->elf; - } - - int cnt = 1; - Elf_Scn *oldscn = NULL, *scn; - while ((oldscn = elf_nextscn (source->oldelf, oldscn)) != NULL) { - GElf_Shdr *oldshdr, oldshdr_mem; - - scn = elf_newscn(elf); - FAILIF_LIBELF(NULL == scn, elf_newscn); - - oldshdr = gelf_getshdr(oldscn, &oldshdr_mem); - FAILIF_LIBELF(NULL == oldshdr, gelf_getshdr); - /* Set the section header of the new section to be the same as the - headset of the old section by default. */ - gelf_update_shdr(scn, oldshdr); - - /* Copy the section data */ - Elf_Data *olddata = elf_getdata(oldscn, NULL); - FAILIF_LIBELF(NULL == olddata, elf_getdata); - - Elf_Data *data = elf_newdata(scn); - FAILIF_LIBELF(NULL == data, elf_newdata); - *data = *olddata; -#if COPY_SECTION_DATA_BUFFER - if (olddata->d_buf != NULL) { - data->d_buf = MALLOC(data->d_size); - memcpy(data->d_buf, olddata->d_buf, olddata->d_size); - } -#endif - - INFO("\tsection %02d: [%-30s] created\n", - cnt, - elf_strptr(source->oldelf, - source->shstrndx, - oldshdr->sh_name)); - - if (ADJUST_ELF) { - ASSERT(source->shdr_info != NULL); - /* Create a new section. */ - source->shdr_info[cnt].idx = cnt; - source->shdr_info[cnt].newscn = scn; - source->shdr_info[cnt].data = data; - source->shdr_info[cnt]. - use_old_shdr_for_relocation_calculations = 1; - INFO("\tsection [%s] (old offset %lld, old size %lld) " - "will have index %d (was %d).\n", - source->shdr_info[cnt].name, - source->shdr_info[cnt].old_shdr.sh_offset, - source->shdr_info[cnt].old_shdr.sh_size, - source->shdr_info[cnt].idx, - elf_ndxscn(source->shdr_info[cnt].scn)); - /* Same as the next assert */ - ASSERT(elf_ndxscn (source->shdr_info[cnt].newscn) == - source->shdr_info[cnt].idx); - } - - ASSERT(elf_ndxscn(scn) == (size_t)cnt); - cnt++; - } -} - -/* This function sets up the shdr_info[] array of a source_t. We call it only - when ADJUST_ELF is non-zero (i.e., support for adjusting an ELF file for - changes in sizes and numbers of relocation sections is compiled in. Note - that setup_shdr_info() depends only on the information in source->oldelf, - not on source->elf. -*/ - -static void setup_shdr_info(source_t *source) -{ - if (ADJUST_ELF) - { - /* Allocate the section-header-info buffer. */ - INFO("Allocating section-header info structure (%d) bytes...\n", - source->shnum * sizeof (shdr_info_t)); - - source->shdr_info = (shdr_info_t *)CALLOC(source->shnum, - sizeof (shdr_info_t)); - - /* Mark the SHT_NULL section as handled. */ - source->shdr_info[0].idx = 2; - - int cnt = 1; - Elf_Scn *oldscn = NULL; - while ((oldscn = elf_nextscn (source->oldelf, oldscn)) != NULL) { - /* Copy the section header */ - ASSERT(elf_ndxscn(oldscn) == (size_t)cnt); - - /* Initialized the corresponding shdr_info entry */ - { - /* Mark the section with a non-zero index. Later, when we - decide to drop a section, we will set its idx to zero, and - assign section numbers to the remaining sections. - */ - source->shdr_info[cnt].idx = 1; - - source->shdr_info[cnt].scn = oldscn; - - /* NOTE: Here we pupulate the section-headset struct with the - same values as the original section's. After the - first run of prelink(), we will update the sh_size - fields of those sections that need resizing. - */ - FAILIF_LIBELF(NULL == - gelf_getshdr(oldscn, - &source->shdr_info[cnt].shdr), - gelf_getshdr); - - /* Get the name of the section. */ - source->shdr_info[cnt].name = - elf_strptr (source->oldelf, source->shstrndx, - source->shdr_info[cnt].shdr.sh_name); - - INFO("\tname: %s\n", source->shdr_info[cnt].name); - FAILIF(source->shdr_info[cnt].name == NULL, - "Malformed file: section %d name is null\n", - cnt); - - /* Remember the shdr.sh_link value. We need to remember this - value for those sections that refer to other sections. For - example, we need to remember it for relocation-entry - sections, because if we modify the symbol table that a - relocation-entry section is relative to, then we need to - patch the relocation section. By the time we get to - deciding whether we need to patch the relocation section, we - will have overwritten its header's sh_link field with a new - value. - */ - source->shdr_info[cnt].old_shdr = source->shdr_info[cnt].shdr; - INFO("\t\toriginal sh_link: %08d\n", - source->shdr_info[cnt].old_shdr.sh_link); - INFO("\t\toriginal sh_addr: %lld\n", - source->shdr_info[cnt].old_shdr.sh_addr); - INFO("\t\toriginal sh_offset: %lld\n", - source->shdr_info[cnt].old_shdr.sh_offset); - INFO("\t\toriginal sh_size: %lld\n", - source->shdr_info[cnt].old_shdr.sh_size); - - FAILIF(source->shdr_info[cnt].shdr.sh_type == SHT_SYMTAB_SHNDX, - "Cannot handle sh_type SHT_SYMTAB_SHNDX!\n"); - FAILIF(source->shdr_info[cnt].shdr.sh_type == SHT_GROUP, - "Cannot handle sh_type SHT_GROUP!\n"); - FAILIF(source->shdr_info[cnt].shdr.sh_type == SHT_GNU_versym, - "Cannot handle sh_type SHT_GNU_versym!\n"); - } - - cnt++; - } /* for each section */ - } /* if (ADJUST_ELF) */ -} - -static Elf * init_elf(source_t *source, bool create_new_sections) -{ - Elf *elf; - if (source->output != NULL) { - if (source->output_is_dir) { - source->output_is_dir++; - char *dir = source->output; - int dirlen = strlen(dir); - /* The main() function maintains a pointer to source->output; it - frees the buffer after apriori() returns. - */ - source->output = MALLOC(dirlen + - 1 + /* slash */ - strlen(source->name) + - 1); /* null terminator */ - strcpy(source->output, dir); - source->output[dirlen] = '/'; - strcpy(source->output + dirlen + 1, - basename(source->name)); - } - - /* Save some of the info; needed for retouching (ASLR). */ - retouch_init(); - - source->newelf_fd = open(source->output, - O_RDWR | O_CREAT, - 0666); - FAILIF(source->newelf_fd < 0, "open(%s): %s (%d)\n", - source->output, - strerror(errno), - errno); - elf = elf_begin(source->newelf_fd, ELF_C_WRITE, NULL); - FAILIF_LIBELF(elf == NULL, elf_begin); - } else { - elf = elf_clone(source->oldelf, ELF_C_EMPTY); - FAILIF_LIBELF(elf == NULL, elf_clone); - } - - GElf_Ehdr *oldehdr = gelf_getehdr(source->oldelf, &source->old_ehdr_mem); - FAILIF_LIBELF(NULL == oldehdr, gelf_getehdr); - - /* Create new ELF and program headers for the elf file */ - INFO("Creating empty ELF and program headers...\n"); - FAILIF_LIBELF(gelf_newehdr (elf, gelf_getclass (source->oldelf)) == 0, - gelf_newehdr); - FAILIF_LIBELF(oldehdr->e_type != ET_REL - && gelf_newphdr (elf, - oldehdr->e_phnum) == 0, - gelf_newphdr); - - /* Copy the elf header */ - INFO("Copying ELF header...\n"); - GElf_Ehdr *ehdr = gelf_getehdr(elf, &source->ehdr_mem); - FAILIF_LIBELF(NULL == ehdr, gelf_getehdr); - memcpy(ehdr, oldehdr, sizeof(GElf_Ehdr)); - FAILIF_LIBELF(!gelf_update_ehdr(elf, ehdr), gelf_update_ehdr); - - /* Copy out the old program header: notice that if the ELF file does not - have a program header, this loop won't execute. - */ - INFO("Copying ELF program header...\n"); - { - int cnt; - source->phdr_info = (GElf_Phdr *)CALLOC(ehdr->e_phnum, - sizeof(GElf_Phdr)); - for (cnt = 0; cnt < ehdr->e_phnum; ++cnt) { - INFO("\tRetrieving entry %d\n", cnt); - FAILIF_LIBELF(NULL == - gelf_getphdr(source->oldelf, cnt, - source->phdr_info + cnt), - gelf_getphdr); - FAILIF_LIBELF(gelf_update_phdr (elf, cnt, - source->phdr_info + cnt) == 0, - gelf_update_phdr); - } - } - - /* Copy the sections and the section headers. */ - if (create_new_sections) - { - create_elf_sections(source, elf); - } - - /* The ELF library better follows our layout when this is not a - relocatable object file. */ - elf_flagelf (elf, ELF_C_SET, (ehdr->e_type != ET_REL ? ELF_F_LAYOUT : 0)); - - return elf; -} - -static shdr_info_t *lookup_shdr_info_by_new_section( - source_t *source, - const char *sname, - Elf_Scn *newscn) -{ - if (source->shdr_info == NULL) return NULL; - int cnt; - for (cnt = 0; cnt < source->shnum; cnt++) { - if (source->shdr_info[cnt].newscn == newscn) { - INFO("\t\tnew section at %p matches shdr_info[%d], " - "section [%s]!\n", - newscn, - cnt, - source->shdr_info[cnt].name); - FAILIF(strcmp(sname, source->shdr_info[cnt].name), - "Matched section's name [%s] does not match " - "looked-up section's name [%s]!\n", - source->shdr_info[cnt].name, - sname); - return source->shdr_info + cnt; - } - } - return NULL; -} - -static bool do_init_source(source_t *source, unsigned base) -{ - /* Find various sections. */ - size_t scnidx; - Elf_Scn *scn; - GElf_Shdr *shdr, shdr_mem; - source->sorted_sections = init_range_list(); - INFO("Processing [%s]'s sections...\n", source->name); - for (scnidx = 1; scnidx < (size_t)source->shnum; scnidx++) { - INFO("\tGetting section index %d...\n", scnidx); - scn = elf_getscn(source->elf, scnidx); - if (NULL == scn) { - /* If we get an error from elf_getscn(), it means that a section - at the requested index does not exist. This may happen when - we remove sections. Since we do not update source->shnum - (we can't, since we need to know the original number of sections - to know source->shdr_info[]'s length), we will attempt to - retrieve a section for an index that no longer exists in the - new ELF file. */ - INFO("\tThere is no section at index %d anymore, continuing.\n", - scnidx); - continue; - } - shdr = gelf_getshdr(scn, &shdr_mem); - FAILIF_LIBELF(NULL == shdr, gelf_getshdr); - - /* We haven't modified the shstrtab section, and so shdr->sh_name - has the same value as before. Thus we look up the name based - on the old ELF handle. We cannot use shstrndx on the new ELF - handle because the index of the shstrtab section may have - changed (and calling elf_getshstrndx() returns the same section - index, so libelf can't handle thise ither). - */ - const char *sname = - elf_strptr(source->oldelf, source->shstrndx, shdr->sh_name); - ASSERT(sname); - - INFO("\tAdding [%s] (%lld, %lld)...\n", - sname, - shdr->sh_addr, - shdr->sh_addr + shdr->sh_size); - if ((shdr->sh_flags & SHF_ALLOC) == SHF_ALLOC) { - add_unique_range_nosort(source->sorted_sections, - shdr->sh_addr, - shdr->sh_size, - scn, - handle_range_error, - NULL); /* no user-data destructor */ - } - - if (shdr->sh_type == SHT_DYNSYM) { - source->symtab.scn = scn; - source->symtab.data = elf_getdata(scn, NULL); - FAILIF_LIBELF(NULL == source->symtab.data, elf_getdata); - memcpy(&source->symtab.shdr, shdr, sizeof(GElf_Shdr)); - source->symtab.info = lookup_shdr_info_by_new_section( - source, sname, scn); - ASSERT(source->shdr_info == NULL || source->symtab.info != NULL); - - /* The sh_link field of the section header of the symbol table - contains the index of the associated strings table. */ - source->strtab.scn = elf_getscn(source->elf, - source->symtab.shdr.sh_link); - FAILIF_LIBELF(NULL == source->strtab.scn, elf_getscn); - FAILIF_LIBELF(NULL == gelf_getshdr(source->strtab.scn, - &source->strtab.shdr), - gelf_getshdr); - source->strtab.data = elf_getdata(source->strtab.scn, NULL); - FAILIF_LIBELF(NULL == source->strtab.data, elf_getdata); - source->strtab.info = lookup_shdr_info_by_new_section( - source, - elf_strptr(source->oldelf, source->shstrndx, - source->strtab.shdr.sh_name), - source->strtab.scn); - ASSERT(source->shdr_info == NULL || source->strtab.info != NULL); - } else if (shdr->sh_type == SHT_DYNAMIC) { - source->dynamic.scn = scn; - source->dynamic.data = elf_getdata(scn, NULL); - FAILIF_LIBELF(NULL == source->dynamic.data, elf_getdata); - memcpy(&source->dynamic.shdr, shdr, sizeof(GElf_Shdr)); - source->dynamic.info = lookup_shdr_info_by_new_section( - source, sname, scn); - ASSERT(source->shdr_info == NULL || source->dynamic.info != NULL); - } else if (shdr->sh_type == SHT_HASH) { - source->hash.scn = scn; - source->hash.data = elf_getdata(scn, NULL); - FAILIF_LIBELF(NULL == source->hash.data, elf_getdata); - memcpy(&source->hash.shdr, shdr, sizeof(GElf_Shdr)); - source->hash.info = lookup_shdr_info_by_new_section( - source, sname, scn); - ASSERT(source->shdr_info == NULL || source->hash.info != NULL); - } else if (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA) { - if (source->num_relocation_sections == - source->relocation_sections_size) { - source->relocation_sections_size += 5; - source->relocation_sections = - (section_info_t *)REALLOC(source->relocation_sections, - source->relocation_sections_size * - sizeof(section_info_t)); - } - section_info_t *reloc = - source->relocation_sections + source->num_relocation_sections; - reloc->scn = scn; - reloc->info = lookup_shdr_info_by_new_section(source, sname, scn); - ASSERT(source->shdr_info == NULL || reloc->info != NULL); - reloc->data = elf_getdata(scn, NULL); - FAILIF_LIBELF(NULL == reloc->data, elf_getdata); - memcpy(&reloc->shdr, shdr, sizeof(GElf_Shdr)); - source->num_relocation_sections++; - } else if (!strcmp(sname, ".bss")) { - source->bss.scn = scn; - source->bss.data = elf_getdata(scn, NULL); - source->bss.info = lookup_shdr_info_by_new_section( - source, sname, scn); - ASSERT(source->shdr_info == NULL || source->bss.info != NULL); - /* The BSS section occupies no space in the ELF file. */ - FAILIF_LIBELF(NULL == source->bss.data, elf_getdata) - FAILIF(NULL != source->bss.data->d_buf, - "Enexpected: section [%s] has data!", - sname); - memcpy(&source->bss.shdr, shdr, sizeof(GElf_Shdr)); - } - } - sort_ranges(source->sorted_sections); - - source->unfinished = - (unfinished_relocation_t *)CALLOC(source->num_relocation_sections, - sizeof(unfinished_relocation_t)); - - if (source->dynamic.scn == NULL) { - INFO("File [%s] does not have a dynamic section!\n", source->name); - /* If this is a static executable, we won't update anything. */ - source->dry_run = 1; - return false; - } - - FAILIF(source->symtab.scn == NULL, - "File [%s] does not have a dynamic symbol table!\n", - source->name); - FAILIF(source->hash.scn == NULL, - "File [%s] does not have a hash table!\n", - source->name); - FAILIF(source->hash.shdr.sh_link != elf_ndxscn(source->symtab.scn), - "Hash points to section %d, not to %d as expected!\n", - source->hash.shdr.sh_link, - elf_ndxscn(source->symtab.scn)); - - /* Now, find out how many symbols we have and allocate the array of - satisfied symbols. - - NOTE: We don't count the number of undefined symbols here; we will - iterate over the symbol table later, and count them then, when it is - more convenient. - */ - size_t symsize = gelf_fsize (source->elf, - ELF_T_SYM, - 1, source->elf_hdr.e_version); - ASSERT(symsize); - - source->num_syms = source->symtab.data->d_size / symsize; - source->base = (source->oldelf_hdr.e_type == ET_DYN) ? base : 0; - INFO("Relink base for [%s]: 0x%lx\n", source->name, source->base); - FAILIF(source->base == -1, - "Can't prelink [%s]: it's a shared library and you did not " - "provide a prelink address!\n", - source->name); -#ifdef SUPPORT_ANDROID_PRELINK_TAGS - FAILIF(source->prelinked && source->base != source->prelink_base, - "ERROR: file [%s] has already been prelinked for 0x%08lx. " - "Cannot change to 0x%08lx!\n", - source->name, - source->prelink_base, - source->base); -#endif/*SUPPORT_ANDROID_PRELINK_TAGS*/ - - return true; -} - -static source_t* init_source(const char *full_path, - const char *output, int is_file, - int base, int dry_run) -{ - source_t *source = (source_t *)CALLOC(1, sizeof(source_t)); - - ASSERT(full_path); - source->name = full_path; - source->output = output; - source->output_is_dir = !is_file; - - source->newelf_fd = -1; - source->elf_fd = -1; - INFO("Opening %s...\n", full_path); - source->elf_fd = - open(full_path, ((dry_run || output != NULL) ? O_RDONLY : O_RDWR)); - FAILIF(source->elf_fd < 0, "open(%s): %s (%d)\n", - full_path, - strerror(errno), - errno); - - FAILIF(fstat(source->elf_fd, &source->elf_file_info) < 0, - "fstat(%s(fd %d)): %s (%d)\n", - source->name, - source->elf_fd, - strerror(errno), - errno); - INFO("File [%s]'s size is %lld bytes!\n", - source->name, - source->elf_file_info.st_size); - - INFO("Calling elf_begin(%s)...\n", full_path); - - source->oldelf = - elf_begin(source->elf_fd, - (dry_run || output != NULL) ? ELF_C_READ : ELF_C_RDWR, - NULL); - FAILIF_LIBELF(source->oldelf == NULL, elf_begin); - - /* libelf can recognize COFF and A.OUT formats, but we handle only ELF. */ - if(elf_kind(source->oldelf) != ELF_K_ELF) { - ERROR("Input file %s is not in ELF format!\n", full_path); - return NULL; - } - - /* Make sure this is a shared library or an executable. */ - { - INFO("Making sure %s is a shared library or an executable...\n", - full_path); - FAILIF_LIBELF(0 == gelf_getehdr(source->oldelf, &source->oldelf_hdr), - gelf_getehdr); - FAILIF(source->oldelf_hdr.e_type != ET_DYN && - source->oldelf_hdr.e_type != ET_EXEC, - "%s must be a shared library (elf type is %d, expecting %d).\n", - full_path, - source->oldelf_hdr.e_type, - ET_DYN); - } - -#ifdef SUPPORT_ANDROID_PRELINK_TAGS - /* First, check to see if the file has been prelinked. */ - source->prelinked = - check_prelinked(source->name, - source->oldelf_hdr.e_ident[EI_DATA] == ELFDATA2LSB, - &source->prelink_base); - /* Note that in the INFO() below we need to use oldelf_hdr because we - haven't cloned the ELF file yet, and source->elf_hdr is not defined. */ - if (source->prelinked) { - PRINT("%s [%s] is already prelinked at 0x%08lx!\n", - (source->oldelf_hdr.e_type == ET_EXEC ? - "Executable" : "Shared library"), - source->name, - source->prelink_base); - /* Force a dry run when the file has already been prelinked */ - source->dry_run = dry_run = 1; - } - else { - INFO("%s [%s] is not prelinked!\n", - (source->oldelf_hdr.e_type == ET_EXEC ? - "Executable" : "Shared library"), - source->name); - source->dry_run = dry_run; - } -#endif/*SUPPORT_ANDROID_PRELINK_TAGS*/ - - /* Get the index of the section-header-strings-table section. */ - FAILIF_LIBELF(elf_getshstrndx (source->oldelf, &source->shstrndx) < 0, - elf_getshstrndx); - - FAILIF_LIBELF(elf_getshnum (source->oldelf, (size_t *)&source->shnum) < 0, - elf_getshnum); - - /* When we have a dry run, or when ADJUST_ELF is enabled, we use - source->oldelf for source->elf, because the former is mmapped privately, - so changes to it have no effect. With ADJUST_ELF, the first run of - prelink() is a dry run. We will reopen the elf file for write access - after that dry run, before we call adjust_elf. */ - - source->elf = (ADJUST_ELF || source->dry_run) ? - source->oldelf : init_elf(source, ADJUST_ELF == 0); - - FAILIF_LIBELF(0 == gelf_getehdr(source->elf, &source->elf_hdr), - gelf_getehdr); -#ifdef DEBUG - ASSERT(!memcmp(&source->oldelf_hdr, - &source->elf_hdr, - sizeof(source->elf_hdr))); -#endif - - /* Get the EBL handling. The -g option is currently the only reason - we need EBL so dont open the backend unless necessary. */ - source->ebl = ebl_openbackend (source->elf); - FAILIF_LIBELF(NULL == source->ebl, ebl_openbackend); -#ifdef ARM_SPECIFIC_HACKS - FAILIF_LIBELF(0 != arm_init(source->elf, source->elf_hdr.e_machine, - source->ebl, sizeof(Ebl)), - arm_init); -#endif/*ARM_SPECIFIC_HACKS*/ - - add_to_sources(source); - if (do_init_source(source, base) == false) return NULL; - return source; -} - -/* complements do_init_source() */ -static void do_destroy_source(source_t *source) -{ - int cnt; - destroy_range_list(source->sorted_sections); - source->sorted_sections = NULL; - for (cnt = 0; cnt < source->num_relocation_sections; cnt++) { - FREEIF(source->unfinished[cnt].rels); - source->unfinished[cnt].rels = NULL; - source->unfinished[cnt].num_rels = 0; - source->unfinished[cnt].rels_size = 0; - } - if (source->jmprel.sections != NULL) { - destroy_range_list(source->jmprel.sections); - source->jmprel.sections = NULL; - } - if (source->rel.sections != NULL) { - destroy_range_list(source->rel.sections); - source->rel.sections = NULL; - } - FREE(source->unfinished); /* do_init_source() */ - source->unfinished = NULL; - FREE(source->relocation_sections); /* do_init_source() */ - source->relocation_sections = NULL; - source->num_relocation_sections = source->relocation_sections_size = 0; -} - -static void destroy_source(source_t *source) -{ - /* Is this a little-endian ELF file? */ - if (source->oldelf != source->elf) { - /* If it's a dynamic executable, this must not be a dry run. */ - if (!source->dry_run && source->dynamic.scn != NULL) - { - FAILIF_LIBELF(elf_update(source->elf, ELF_C_WRITE) == -1, - elf_update); - } - FAILIF_LIBELF(elf_end(source->oldelf), elf_end); - } - ebl_closebackend(source->ebl); - FAILIF_LIBELF(elf_end(source->elf), elf_end); - FAILIF(close(source->elf_fd) < 0, "Could not close file %s: %s (%d)!\n", - source->name, strerror(errno), errno); - FAILIF((source->newelf_fd >= 0) && (close(source->newelf_fd) < 0), - "Could not close output file: %s (%d)!\n", strerror(errno), errno); - -#ifdef SUPPORT_ANDROID_PRELINK_TAGS - if (!source->dry_run) { - if (source->dynamic.scn != NULL && - source->elf_hdr.e_type != ET_EXEC) - { - /* For some reason, trying to write directly to source->elf_fd - causes a "bad file descriptor" error because of something libelf - does. We just close the file descriptor and open a new one in - function setup_prelink_info() below. */ - INFO("%s: setting up prelink tag at end of file.\n", - source->output ? source->output : source->name); - retouch_encode(-1, source->base); - retouch_dump(source->output ? source->output : source->name, - source->elf_hdr.e_ident[EI_DATA] == ELFDATA2LSB, - retouch_byte_cnt, - retouch_buf); - setup_prelink_info(source->output ? source->output : source->name, - source->elf_hdr.e_ident[EI_DATA] == ELFDATA2LSB, - source->base); - } - else INFO("%s: executable, NOT setting up prelink tag.\n", - source->name); - } -#endif/*SUPPORT_ANDROID_PRELINK_TAGS*/ - - do_destroy_source(source); - if (retouch_buf != NULL) { free(retouch_buf); retouch_buf = NULL; } - - if (source->shstrtab_data != NULL) - FREEIF(source->shstrtab_data->d_buf); /* adjust_elf */ - - FREE(source->lib_deps); /* list of library dependencies (process_file()) */ - FREEIF(source->shdr_info); /* setup_shdr_info() */ - FREEIF(source->phdr_info); /* init_elf() */ - FREE(source->name); /* assigned to by init_source() */ - /* If the output is a directory, in init_elf() we allocate a buffer where - we copy the directory, a slash, and the file name. Here we free that - buffer. - */ - if (source->output_is_dir > 1) { - FREE(source->output); - } - FREE(source); /* init_source() */ -} - -static void reinit_source(source_t *source) -{ - do_destroy_source(source); - do_init_source(source, source->base); - - { - /* We've gathered all the DT_DYNAMIC entries; now we need to figure - out which relocation sections fit in which range as described by - the entries. Before we do so, however, we will populate the - jmprel and rel members of source, as well as their sizes. - */ - - size_t dynidx, numdyn; - GElf_Dyn *dyn, dyn_mem; - - numdyn = source->dynamic.shdr.sh_size / - source->dynamic.shdr.sh_entsize; - - source->rel.idx = source->rel.sz_idx = -1; - source->jmprel.idx = source->jmprel.sz_idx = -1; - for (dynidx = 0; dynidx < numdyn; dynidx++) { - dyn = gelf_getdyn (source->dynamic.data, - dynidx, - &dyn_mem); - FAILIF_LIBELF(NULL == dyn, gelf_getdyn); - switch (dyn->d_tag) - { - case DT_NEEDED: - break; - case DT_JMPREL: - INFO("reinit_source: DT_JMPREL is at index %d, 0x%08llx.\n", - dynidx, dyn->d_un.d_ptr); - source->jmprel.idx = dynidx; - source->jmprel.addr = dyn->d_un.d_ptr; - break; - case DT_PLTRELSZ: - INFO("reinit_source: DT_PLTRELSZ is at index %d, 0x%08llx.\n", - dynidx, dyn->d_un.d_val); - source->jmprel.sz_idx = dynidx; - source->jmprel.size = dyn->d_un.d_val; - break; - case DT_REL: - INFO("reinit_source: DT_REL is at index %d, 0x%08llx.\n", - dynidx, dyn->d_un.d_ptr); - source->rel.idx = dynidx; - source->rel.addr = dyn->d_un.d_ptr; - break; - case DT_RELSZ: - INFO("reinit_source: DT_RELSZ is at index %d, 0x%08llx.\n", - dynidx, dyn->d_un.d_val); - source->rel.sz_idx = dynidx; - source->rel.size = dyn->d_un.d_val; - break; - case DT_RELA: - case DT_RELASZ: - FAILIF(1, "Can't handle DT_RELA and DT_RELASZ entries!\n"); - break; - } /* switch */ - } /* for each dynamic entry... */ - } -} - -static GElf_Sym *hash_lookup_global_or_weak_symbol(source_t *lib, - const char *symname, - GElf_Sym *lib_sym_mem) -{ - int lib_symidx = hash_lookup(lib->elf, - lib->hash.data, - lib->symtab.data, - lib->strtab.data, - symname); - - GElf_Sym sym_mem; - if (SHN_UNDEF != lib_symidx) { - /* We found the symbol--now check to see if it is global - or weak. If this is the case, then the symbol satisfies - the dependency. */ - GElf_Sym *lib_sym = gelf_getsymshndx(lib->symtab.data, - NULL, - lib_symidx, - &sym_mem, - NULL); - FAILIF_LIBELF(NULL == lib_sym, gelf_getsymshndx); -#if ELF_STRPTR_IS_BROKEN - ASSERT(!strcmp( - symname, - ((char *)elf_getdata(elf_getscn(lib->elf, - lib->symtab.shdr.sh_link), - NULL)->d_buf) + - lib_sym->st_name)); -#else - ASSERT(!strcmp( - symname, - elf_strptr(lib->elf, lib->symtab.shdr.sh_link, - lib_sym->st_name))); -#endif - if (lib_sym->st_shndx != SHN_UNDEF && - (GELF_ST_BIND(lib_sym->st_info) == STB_GLOBAL || - GELF_ST_BIND(lib_sym->st_info) == STB_WEAK)) { - memcpy(lib_sym_mem, &sym_mem, sizeof(GElf_Sym)); - return lib_sym; - } - } - - return NULL; -} - -static source_t *lookup_symbol_in_dependencies(source_t *source, - const char *symname, - GElf_Sym *found_sym) -{ - source_t *sym_source = NULL; /* return value */ - - /* This is an undefined symbol. Go over the list of libraries - and look it up. */ - size_t libidx; - int found = 0; - source_t *last_found = NULL; - for (libidx = 0; libidx < (size_t)source->num_lib_deps; libidx++) { - source_t *lib = source->lib_deps[libidx]; - if (hash_lookup_global_or_weak_symbol(lib, symname, found_sym) != NULL) - { - sym_source = lib; - if (found) { - if (found == 1) { - found++; - ERROR("ERROR: multiple definitions found for [%s:%s]!\n", - source->name, symname); - ERROR("\tthis definition [%s]\n", lib->name); - } - ERROR("\tprevious definition [%s]\n", last_found->name); - } - last_found = lib; - if (!found) found = 1; - } - } - -#if ELF_STRPTR_IS_BROKEN - ASSERT(!sym_source || - !strcmp(symname, - (char *)(elf_getdata(elf_getscn( - sym_source->elf, - sym_source->symtab.shdr.sh_link), - NULL)->d_buf) + - found_sym->st_name)); -#else - ASSERT(!sym_source || - !strcmp(symname, - elf_strptr(sym_source->elf, - sym_source->symtab.shdr.sh_link, - found_sym->st_name))); -#endif - - return sym_source; -} - -static int do_prelink(source_t *source, - Elf_Data *reloc_scn_data, - int reloc_scn_entry_size, - unfinished_relocation_t *unfinished, - int locals_only, - bool dry_run, - char **lib_lookup_dirs, int num_lib_lookup_dirs, - char **default_libs, int num_default_libs, - int *num_unfinished_relocs) -{ - int num_relocations = 0; - - size_t num_rels; - num_rels = reloc_scn_data->d_size / reloc_scn_entry_size; - - INFO("\tThere are %d relocations.\n", num_rels); - - int rel_idx; - for (rel_idx = 0; rel_idx < (size_t)num_rels; rel_idx++) { - GElf_Rel *rel, rel_mem; - - //INFO("\tHandling relocation %d/%d\n", rel_idx, num_rels); - - rel = gelf_getrel(reloc_scn_data, rel_idx, &rel_mem); - FAILIF_LIBELF(rel == NULL, gelf_getrel); - GElf_Sym *sym = NULL, sym_mem; - unsigned sym_idx = GELF_R_SYM(rel->r_info); - source_t *sym_source = NULL; - /* found_sym points to found_sym_mem, when sym_source != NULL, and - to sym, when the sybmol is locally defined. If the symbol is - not locally defined and sym_source == NULL, then sym is not - defined either. */ - GElf_Sym *found_sym = NULL, found_sym_mem; - const char *symname = NULL; - int sym_is_local = 1; - if (sym_idx) { - sym = gelf_getsymshndx(source->symtab.data, - NULL, - sym_idx, - &sym_mem, - NULL); - FAILIF_LIBELF(NULL == sym, gelf_getsymshndx); -#if ELF_STRPTR_IS_BROKEN - symname = - ((char *)source->strtab.data->d_buf) + - sym->st_name; -#else - symname = elf_strptr(source->elf, - elf_ndxscn(source->strtab.scn), - sym->st_name); -#endif - - /* If the symbol is defined and is either not in the BSS - section, or if it is in the BSS then the relocation is - not a copy relocation, then the symbol's source is this - library (i.e., it is locally-defined). Otherwise, the - symbol is imported. - */ - - sym_is_local = 0; - if (sym->st_shndx != SHN_UNDEF && - (source->bss.scn == NULL || - sym->st_shndx != elf_ndxscn(source->bss.scn) || -#ifdef ARM_SPECIFIC_HACKS - GELF_R_TYPE(rel->r_info) != R_ARM_COPY -#else - 1 -#endif - )) - { - sym_is_local = 1; - } - - if (sym_is_local) { - INFO("\t\tSymbol [%s:%s] is defined locally.\n", - source->name, - symname); - sym_source = source; - found_sym = sym; - } - else if (!locals_only) { - sym_source = lookup_symbol_in_dependencies(source, - symname, - &found_sym_mem); - - /* The symbol was not in the list of dependencies, which by - itself is an error: it means either that the symbol does - not exist anywhere, or that the library which has the symbol - has not been listed as a dependency in this library or - executable. It could also mean (for a library) that the - symbol is defined in the executable that links agsinst it, - which is obviously not a good thing. These are bad things, - but they do happen, which is why we have the ability to - provide a list of default dependencies, including - executables. Here we check to see if the symbol has been - defined in any of them. - */ - if (NULL == sym_source) { - INFO("\t\tChecking default dependencies...\n"); - int i; - source_t *lib, *old_sym_source = NULL; - int printed_initial_error = 0; - for (i = 0; i < num_default_libs; i++) { - INFO("\tChecking in [%s].\n", default_libs[i]); - lib = find_source(default_libs[i], - lib_lookup_dirs, - num_lib_lookup_dirs); - FAILIF(NULL == lib, - "Can't find default library [%s]!\n", - default_libs[i]); - if (hash_lookup_global_or_weak_symbol(lib, - symname, - &found_sym_mem)) { - found_sym = &found_sym_mem; - sym_source = lib; -#if ELF_STRPTR_IS_BROKEN - ASSERT(!strcmp(symname, - (char *)(elf_getdata( - elf_getscn( - sym_source->elf, - sym_source->symtab. - shdr.sh_link), - NULL)->d_buf) + - found_sym->st_name)); -#else - ASSERT(!strcmp(symname, - elf_strptr(sym_source->elf, - sym_source->symtab.shdr.sh_link, - found_sym->st_name))); - -#endif - INFO("\tFound symbol [%s] in [%s]!\n", - symname, lib->name); - if (old_sym_source) { - if (printed_initial_error == 0) { - printed_initial_error = 1; - ERROR("Multiple definition of [%s]:\n" - "\t[%s]\n", - symname, - old_sym_source->name); - } - ERROR("\t[%s]\n", sym_source->name); - } - old_sym_source = sym_source; - } else { - INFO("\tCould not find symbol [%s] in default " - "lib [%s]!\n", symname, lib->name); - } - } - if (sym_source) { - ERROR("ERROR: Could not find [%s:%s] in dependent " - "libraries (but found in default [%s])!\n", - source->name, - symname, - sym_source->name); - } - } else { - found_sym = &found_sym_mem; - /* We found the symbol in a dependency library. */ - INFO("\t\tSymbol [%s:%s, value %lld] is imported from [%s]\n", - source->name, - symname, - found_sym->st_value, - sym_source->name); - } - } /* if symbol is defined in this library... */ - - if (!locals_only) { - /* If a symbol is weak and we haven't found it, then report - an error. We really need to find a way to set its value - to zero. The problem is that it needs to refer to some - section. */ - - FAILIF(NULL == sym_source && - GELF_ST_BIND(sym->st_info) == STB_WEAK, - "Cannot handle weak symbols yet (%s:%s <- %s).\n", - source->name, - symname, - sym_source->name); -#ifdef PERMISSIVE - if (GELF_ST_BIND(sym->st_info) != STB_WEAK && - NULL == sym_source) { - ERROR("ERROR: Can't find symbol [%s:%s] in dependent or " - "default libraries!\n", source->name, symname); - } -#else - FAILIF(GELF_ST_BIND(sym->st_info) != STB_WEAK && - NULL == sym_source, - "Can't find symbol [%s:%s] in dependent or default " - "libraries!\n", - source->name, - symname); -#endif - } /* if (!locals_only) */ - } -#if 0 // too chatty - else - INFO("\t\tno symbol is associated with this relocation\n"); -#endif - - - // We prelink only local symbols when locals_only == 1. - - bool can_relocate = true; - if (!sym_is_local && - (symname[0] == 'd' && symname[1] == 'l' && symname[2] != '\0' && - (!strcmp(symname + 2, "open") || - !strcmp(symname + 2, "close") || - !strcmp(symname + 2, "sym") || - !strcmp(symname + 2, "error")))) { - INFO("********* NOT RELOCATING LIBDL SYMBOL [%s]\n", symname); - can_relocate = false; - } - - if (can_relocate && (sym_is_local || !locals_only)) - { - GElf_Shdr shdr_mem; Elf_Scn *scn; Elf_Data *data; - find_section(source, rel->r_offset, &scn, &shdr_mem, &data); - unsigned *dest = - (unsigned*)(((char *)data->d_buf) + - (rel->r_offset - shdr_mem.sh_addr)); - unsigned rel_type = GELF_R_TYPE(rel->r_info); - char buf[64]; - INFO("\t\t%-15s ", - ebl_reloc_type_name(source->ebl, - GELF_R_TYPE(rel->r_info), - buf, - sizeof(buf))); - - /* Section-name offsets do not change, so we use oldelf to get the - strings. This makes a difference in the second pass of the - perlinker, after the call to adjust_elf, because - source->shstrndx no longer contains the index of the - section-header-strings table. - */ - const char *sname = elf_strptr( - source->oldelf, source->shstrndx, shdr_mem.sh_name); - - switch (rel_type) { - case R_ARM_JUMP_SLOT: - case R_ARM_GLOB_DAT: - case R_ARM_ABS32: - ASSERT(data->d_buf != NULL); - ASSERT(data->d_size >= rel->r_offset - shdr_mem.sh_addr); -#ifdef PERMISSIVE - if (sym_source == NULL) { - ERROR("ERROR: Permissive relocation " - "[%-15s] [%s:%s]: [0x%llx] = ZERO\n", - ebl_reloc_type_name(source->ebl, - GELF_R_TYPE(rel->r_info), - buf, - sizeof(buf)), - sname, - symname, - rel->r_offset); - if (!dry_run) - *dest = 0; - } else -#endif - { - ASSERT(sym_source); - INFO("[%s:%s]: [0x%llx] = 0x%llx + 0x%lx\n", - sname, - symname, - rel->r_offset, - found_sym->st_value, - sym_source->base); - if (!dry_run) { - PRINT("WARNING: Relocation type not supported " - "for retouching!"); - *dest = found_sym->st_value + sym_source->base; - } - } - num_relocations++; - break; - case R_ARM_RELATIVE: - ASSERT(data->d_buf != NULL); - ASSERT(data->d_size >= rel->r_offset - shdr_mem.sh_addr); - FAILIF(sym != NULL, - "Unsupported RELATIVE form (symbol != 0)...\n"); - INFO("[%s:%s]: [0x%llx] = 0x%x + 0x%lx\n", - sname, - symname ?: "(symbol has no name)", - rel->r_offset, *dest, source->base); - if (!dry_run) { - *dest += source->base; - - /* Output an entry for the ASLR touch-up process. */ - retouch_encode(rel->r_offset - -shdr_mem.sh_addr - +shdr_mem.sh_offset, - *dest); - } - num_relocations++; - break; - case R_ARM_COPY: -#ifdef PERMISSIVE - if (sym_source == NULL) { - ERROR("ERROR: Permissive relocation " - "[%-15s] [%s:%s]: NOT PERFORMING\n", - ebl_reloc_type_name(source->ebl, - GELF_R_TYPE(rel->r_info), - buf, - sizeof(buf)), - sname, - symname); - } else -#endif - { - ASSERT(sym); - ASSERT(sym_source); - GElf_Shdr src_shdr_mem; - Elf_Scn *src_scn; - Elf_Data *src_data; - find_section(sym_source, found_sym->st_value, - &src_scn, - &src_shdr_mem, - &src_data); - INFO("Found [%s:%s (%lld)] in section [%s] .\n", - sym_source->name, - symname, - found_sym->st_value, -#if ELF_STRPTR_IS_BROKEN - (((char *)elf_getdata( - elf_getscn(sym_source->elf, - sym_source->shstrndx), - NULL)->d_buf) + src_shdr_mem.sh_name) -#else - elf_strptr(sym_source->elf, - sym_source->shstrndx, - src_shdr_mem.sh_name) -#endif - ); - - unsigned *src = NULL; - if (src_data->d_buf == NULL) - { -#ifdef PERMISSIVE - if (sym_source->bss.scn == NULL || - elf_ndxscn(src_scn) != - elf_ndxscn(sym_source->bss.scn)) { - ERROR("ERROR: Permissive relocation (NULL source " - "not from .bss) [%-15s] [%s:%s]: " - "NOT PERFORMING\n", - ebl_reloc_type_name(source->ebl, - GELF_R_TYPE(rel->r_info), - buf, - sizeof(buf)), - sname, - symname); - } -#endif - } - else { - ASSERT(src_data->d_size >= - found_sym->st_value - src_shdr_mem.sh_addr); - src = (unsigned*)(((char *)src_data->d_buf) + - (found_sym->st_value - - src_shdr_mem.sh_addr)); - } - ASSERT(symname); - INFO("[%s:%s]: [0x%llx] <- [0x%llx] size %lld\n", - sname, - symname, rel->r_offset, - found_sym->st_value, - found_sym->st_size); - -#ifdef PERMISSIVE - if (src_data->d_buf != NULL || - (sym_source->bss.scn != NULL && - elf_ndxscn(src_scn) == - elf_ndxscn(sym_source->bss.scn))) -#endif/*PERMISSIVE*/ - { - if (data->d_buf == NULL) { - INFO("Incomplete relocation [%-15s] of [%s:%s].\n", - ebl_reloc_type_name(source->ebl, - GELF_R_TYPE(rel->r_info), - buf, - sizeof(buf)), - sname, - symname); - FAILIF(unfinished == NULL, - "You passed unfinished as NULL expecting " - "to handle all relocations, " - "but at least one cannot be handled!\n"); - if (unfinished->num_rels == unfinished->rels_size) { - unfinished->rels_size += 10; - unfinished->rels = (GElf_Rel *)REALLOC( - unfinished->rels, - unfinished->rels_size * - sizeof(GElf_Rel)); - } - unfinished->rels[unfinished->num_rels++] = *rel; - num_relocations--; - (*num_unfinished_relocs)++; - } - else { - if (src_data->d_buf != NULL) - { - ASSERT(data->d_buf != NULL); - ASSERT(data->d_size >= rel->r_offset - - shdr_mem.sh_addr); - if (!dry_run) { - PRINT("WARNING: Relocation type not supported " - "for retouching!"); - memcpy(dest, src, found_sym->st_size); - } - } - else { - ASSERT(src == NULL); - ASSERT(elf_ndxscn(src_scn) == - elf_ndxscn(sym_source->bss.scn)); - if (!dry_run) { - PRINT("WARNING: Relocation type not supported " - "for retouching!"); - memset(dest, 0, found_sym->st_size); - } - } - } - } - num_relocations++; - } - break; - default: - FAILIF(1, "Unknown relocation type %d!\n", rel_type); - } // switch - } // relocate - else { - INFO("\t\tNot relocating symbol [%s]%s\n", - symname, - (can_relocate ? ", relocating only locals" : - ", which is a libdl symbol")); - FAILIF(unfinished == NULL, - "You passed unfinished as NULL expecting to handle all " - "relocations, but at least one cannot be handled!\n"); - if (unfinished->num_rels == unfinished->rels_size) { - unfinished->rels_size += 10; - unfinished->rels = (GElf_Rel *)REALLOC( - unfinished->rels, - unfinished->rels_size * - sizeof(GElf_Rel)); - } - unfinished->rels[unfinished->num_rels++] = *rel; - (*num_unfinished_relocs)++; - } - } // for each relocation entry - - return num_relocations; -} - -static int prelink(source_t *source, - int locals_only, - bool dry_run, - char **lib_lookup_dirs, int num_lib_lookup_dirs, - char **default_libs, int num_default_libs, - int *num_unfinished_relocs) -{ - INFO("Prelinking [%s] (number of relocation sections: %d)%s...\n", - source->name, source->num_relocation_sections, - (dry_run ? " (dry run)" : "")); - int num_relocations = 0; - int rel_scn_idx; - for (rel_scn_idx = 0; rel_scn_idx < source->num_relocation_sections; - rel_scn_idx++) - { - section_info_t *reloc_scn = source->relocation_sections + rel_scn_idx; - unfinished_relocation_t *unfinished = source->unfinished + rel_scn_idx; - - /* We haven't modified the shstrtab section, and so shdr->sh_name has - the same value as before. Thus we look up the name based on the old - ELF handle. We cannot use shstrndx on the new ELF handle because - the index of the shstrtab section may have changed (and calling - elf_getshstrndx() returns the same section index, so libelf can't - handle thise ither). - - If reloc_scn->info is available, we can assert that the - section-name has not changed. If this assertion fails, - then we cannot use the elf_strptr() trick below to get - the section name. One solution would be to save it in - the section_info_t structure. - */ - ASSERT(reloc_scn->info == NULL || - reloc_scn->shdr.sh_name == reloc_scn->info->old_shdr.sh_name); - const char *sname = - elf_strptr(source->oldelf, - source->shstrndx, - reloc_scn->shdr.sh_name); - ASSERT(sname != NULL); - - INFO("\n\tIterating relocation section [%s]...\n", sname); - - /* In general, the new size of the section differs from the original - size of the section, because we can handle some of the relocations. - This was communicated to adjust_elf, which modified the ELF file - according to the new section sizes. Now, when prelink() does the - actual work of prelinking, it needs to know the original size of the - relocation section so that it can see all of the original relocation - entries! - */ - size_t d_size = reloc_scn->data->d_size; - if (reloc_scn->info != NULL && - reloc_scn->data->d_size != reloc_scn->info->old_shdr.sh_size) - { - INFO("Setting size of section [%s] to from new size %d to old " - "size %lld temporarily (so prelinker can see all " - "relocations).\n", - reloc_scn->info->name, - d_size, - reloc_scn->info->old_shdr.sh_size); - reloc_scn->data->d_size = reloc_scn->info->old_shdr.sh_size; - } - - num_relocations += - do_prelink(source, - reloc_scn->data, reloc_scn->shdr.sh_entsize, - unfinished, - locals_only, dry_run, - lib_lookup_dirs, num_lib_lookup_dirs, - default_libs, num_default_libs, - num_unfinished_relocs); - - if (reloc_scn->data->d_size != d_size) - { - ASSERT(reloc_scn->info != NULL); - INFO("Resetting size of section [%s] to %d\n", - reloc_scn->info->name, - d_size); - reloc_scn->data->d_size = d_size; - } - } - - /* Now prelink those relocation sections which were fully handled, and - therefore removed. They are not a part of the - source->relocation_sections[] array anymore, but we can find them by - scanning source->shdr_info[] and looking for sections with idx == 0. - */ - - if (ADJUST_ELF && source->shdr_info != NULL) { - /* Walk over the shdr_info[] array to see if we've removed any - relocation sections. prelink() those sections as well. - */ - int i; - for (i = 0; i < source->shnum; i++) { - shdr_info_t *info = source->shdr_info + i; - if (info->idx == 0 && - (info->shdr.sh_type == SHT_REL || - info->shdr.sh_type == SHT_RELA)) { - - Elf_Data *data = elf_getdata(info->scn, NULL); - ASSERT(data->d_size == 0); - data->d_size = info->old_shdr.sh_size; - - INFO("\n\tIterating relocation section [%s], which was " - "discarded (size %d, entry size %lld).\n", - info->name, - data->d_size, - info->old_shdr.sh_entsize); - - num_relocations += - do_prelink(source, - data, info->old_shdr.sh_entsize, - NULL, /* the section was fully handled */ - locals_only, dry_run, - lib_lookup_dirs, num_lib_lookup_dirs, - default_libs, num_default_libs, - num_unfinished_relocs); - - data->d_size = 0; - } - } - } - return num_relocations; -} - -static char * find_file(const char *libname, - char **lib_lookup_dirs, - int num_lib_lookup_dirs) { - if (libname[0] == '/') { - /* This is an absolute path name--just return it. */ - /* INFO("ABSOLUTE PATH: [%s].\n", libname); */ - return strdup(libname); - } else { - /* First try the working directory. */ - int fd; - if ((fd = open(libname, O_RDONLY)) > 0) { - close(fd); - /* INFO("FOUND IN CURRENT DIR: [%s].\n", libname); */ - return strdup(libname); - } else { - /* Iterate over all library paths. For each path, append the file - name and see if there is a file at that place. If that fails, - bail out. */ - - char *name; - while (num_lib_lookup_dirs--) { - size_t lib_len = strlen(*lib_lookup_dirs); - /* one extra character for the slash, and another for the - terminating NULL. */ - name = (char *)MALLOC(lib_len + strlen(libname) + 2); - strcpy(name, *lib_lookup_dirs); - name[lib_len] = '/'; - strcpy(name + lib_len + 1, libname); - if ((fd = open(name, O_RDONLY)) > 0) { - close(fd); - /* INFO("FOUND: [%s] in [%s].\n", libname, name); */ - return name; - } - INFO("NOT FOUND: [%s] in [%s].\n", libname, name); - free(name); - } - } - } - return NULL; -} - -static void adjust_dynamic_segment_entry_size(source_t *source, - dt_rel_info_t *dyn) -{ - /* Update the size entry in the DT_DYNAMIC segment. */ - GElf_Dyn *dyn_entry, dyn_entry_mem; - dyn_entry = gelf_getdyn(source->dynamic.data, - dyn->sz_idx, - &dyn_entry_mem); - FAILIF_LIBELF(NULL == dyn_entry, gelf_getdyn); - /* If we are calling this function to adjust the size of the dynamic entry, - then there should be some unfinished relocations remaining. If there - are none, then we should remove the entry from the dynamic section - altogether. - */ - ASSERT(dyn->num_unfinished_relocs); - - size_t relsize = gelf_fsize(source->elf, - ELF_T_REL, - 1, - source->elf_hdr.e_version); - - if (unlikely(verbose_flag)) { - char buf[64]; - INFO("Updating entry %d: [%-10s], %08llx --> %08x\n", - dyn->sz_idx, - ebl_dynamic_tag_name (source->ebl, dyn_entry->d_tag, - buf, sizeof (buf)), - dyn_entry->d_un.d_val, - dyn->num_unfinished_relocs * relsize); - } - - dyn_entry->d_un.d_val = dyn->num_unfinished_relocs * relsize; - - FAILIF_LIBELF(!gelf_update_dyn(source->dynamic.data, - dyn->sz_idx, - dyn_entry), - gelf_update_dyn); -} - -static void adjust_dynamic_segment_entries(source_t *source) -{ - /* This function many remove entries from the dynamic segment, but it won't - resize the relevant section. It'll just fill the remainted with empty - DT entries. - - FIXME: This is not guaranteed right now. If a dynamic segment does not - end with null DT entries, I think this will break. - */ - FAILIF(source->rel.processed, - "More than one section matches DT_REL entry in dynamic segment!\n"); - FAILIF(source->jmprel.processed, - "More than one section matches DT_JMPREL entry in " - "dynamic segment!\n"); - source->rel.processed = - source->jmprel.processed = 1; - - if (source->rel.num_unfinished_relocs > 0) - adjust_dynamic_segment_entry_size(source, &source->rel); - - if (source->jmprel.num_unfinished_relocs > 0) - adjust_dynamic_segment_entry_size(source, &source->jmprel); - - /* If at least one of the entries is empty, then we need to remove it. We - have already adjusted the size of the other. - */ - if (source->rel.num_unfinished_relocs == 0 || - source->jmprel.num_unfinished_relocs == 0) - { - /* We need to delete the DT_REL/DT_RELSZ and DT_PLTREL/DT_PLTRELSZ - entries from the dynamic segment. */ - - GElf_Dyn *dyn_entry, dyn_entry_mem; - size_t dynidx, updateidx; - - size_t numdyn = - source->dynamic.shdr.sh_size / - source->dynamic.shdr.sh_entsize; - - for (updateidx = dynidx = 0; dynidx < numdyn; dynidx++) - { - dyn_entry = gelf_getdyn(source->dynamic.data, - dynidx, - &dyn_entry_mem); - FAILIF_LIBELF(NULL == dyn_entry, gelf_getdyn); - if ((source->rel.num_unfinished_relocs == 0 && - (dynidx == source->rel.idx || - dynidx == source->rel.sz_idx)) || - (source->jmprel.num_unfinished_relocs == 0 && - (dynidx == source->jmprel.idx || - dynidx == source->jmprel.sz_idx))) - { - if (unlikely(verbose_flag)) { - char buf[64]; - INFO("\t(!)\tRemoving entry %02d: [%-10s], %08llx\n", - dynidx, - ebl_dynamic_tag_name (source->ebl, dyn_entry->d_tag, - buf, sizeof (buf)), - dyn_entry->d_un.d_val); - } - continue; - } - - if (unlikely(verbose_flag)) { - char buf[64]; - INFO("\t\tKeeping entry %02d: [%-10s], %08llx\n", - dynidx, - ebl_dynamic_tag_name (source->ebl, dyn_entry->d_tag, - buf, sizeof (buf)), - dyn_entry->d_un.d_val); - } - - gelf_update_dyn(source->dynamic.data, - updateidx, - &dyn_entry_mem); - updateidx++; - } - } -} /* adjust_dynamic_segment_entries */ - -static bool adjust_dynamic_segment_for(source_t *source, - dt_rel_info_t *dyn, - bool adjust_section_size_only) -{ - bool dropped_sections = false; - - /* Go over the sections that belong to this dynamic range. */ - dyn->num_unfinished_relocs = 0; - if (dyn->sections) { - int num_scns, idx; - range_t *scns = get_sorted_ranges(dyn->sections, &num_scns); - - INFO("\tdynamic range %s:[%lld, %lld) contains %d sections.\n", - source->name, - dyn->addr, - dyn->addr + dyn->size, - num_scns); - - ASSERT(scns); - int next_idx = 0, next_rel_off = 0; - /* The total number of unfinished relocations for this dynamic - * entry. */ - section_info_t *next = (section_info_t *)scns[next_idx].user; - section_info_t *first = next; - ASSERT(first); - for (idx = 0; idx < num_scns; idx++) { - section_info_t *reloc_scn = (section_info_t *)scns[idx].user; - size_t rel_scn_idx = reloc_scn - source->relocation_sections; - ASSERT(rel_scn_idx < (size_t)source->num_relocation_sections); - unfinished_relocation_t *unfinished = - &source->unfinished[rel_scn_idx]; - int unf_idx; - - ASSERT(reloc_scn->info == NULL || - reloc_scn->shdr.sh_name == - reloc_scn->info->old_shdr.sh_name); - const char *sname = - elf_strptr(source->oldelf, - source->shstrndx, - reloc_scn->shdr.sh_name); - - INFO("\tsection [%s] contains %d unfinished relocs.\n", - sname, - unfinished->num_rels); - - for (unf_idx = 0; unf_idx < unfinished->num_rels; unf_idx++) - { - /* There are unfinished relocations. Copy them forward to the - lowest section we can. */ - - while (next_rel_off == - (int)(next->shdr.sh_size/next->shdr.sh_entsize)) - { - INFO("\tsection [%s] has filled up with %d unfinished " - "relocs.\n", - sname, - next_rel_off); - - next_idx++; - ASSERT(next_idx <= idx); - next = (section_info_t *)scns[next_idx].user; - next_rel_off = 0; - } - - if (!adjust_section_size_only) { - INFO("\t\tmoving unfinished relocation %2d to [%s:%d]\n", - unf_idx, - sname, - next_rel_off); - FAILIF_LIBELF(0 == - gelf_update_rel(next->data, - next_rel_off, - &unfinished->rels[unf_idx]), - gelf_update_rel); - } - - next_rel_off++; - dyn->num_unfinished_relocs++; - } - } /* for */ - - /* Set the size of the last section, and mark all subsequent - sections for removal. At this point, next is the section - to which we last wrote data, next_rel_off is the offset before - which we wrote the last relocation, and so next_rel_off * - relsize is the new size of the section. - */ - - bool adjust_file = ADJUST_ELF && source->elf_hdr.e_type != ET_EXEC; - if (adjust_file && !source->dry_run) - { - size_t relsize = gelf_fsize(source->elf, - ELF_T_REL, - 1, - source->elf_hdr.e_version); - - ASSERT(next->info == NULL || - next->shdr.sh_name == next->info->old_shdr.sh_name); - const char *sname = - elf_strptr(source->oldelf, - source->shstrndx, - next->shdr.sh_name); - - INFO("\tsection [%s] (index %d) has %d unfinished relocs, " - "changing its size to %ld bytes (from %ld bytes).\n", - sname, - elf_ndxscn(next->scn), - next_rel_off, - (long)(next_rel_off * relsize), - (long)(next->shdr.sh_size)); - - /* source->shdr_info[] must be allocated prior to calling this - function. This is in fact done in process_file(), by calling - setup_shdr_info() just before we call adjust_dynamic_segment(). - */ - ASSERT(source->shdr_info != NULL); - - /* We do not update the data field of shdr_info[], because it does - not exist yet (with ADJUST_ELF != 0). We create the new section - and section data after the first call to prelink(). For now, we - save the results of our analysis by modifying the sh_size field - of the section header. When we create the new sections' data, - we set the size of the data from the sh_size fields of the - section headers. - - NOTE: The assertion applies only to the first call of - adjust_dynamic_segment (which calls this function). By - the second call, we've already created the data for the - new sections. The only sections for which we haven't - created data are the relocation sections we are removing. - */ -#ifdef DEBUG - ASSERT((!adjust_section_size_only && - (source->shdr_info[elf_ndxscn(next->scn)].idx > 0)) || - source->shdr_info[elf_ndxscn(next->scn)].data == NULL); -#endif - - //FIXME: what else do we need to do here? Do we need to update - // another copy of the shdr so that it's picked up when we - // commit the file? - next->shdr.sh_size = next_rel_off * relsize; - source->shdr_info[elf_ndxscn(next->scn)].shdr.sh_size = - next->shdr.sh_size; - if (next_rel_off * relsize == 0) { -#ifdef REMOVE_HANDLED_SECTIONS - INFO("\tsection [%s] (index %d) is now empty, marking for " - "removal.\n", - sname, - elf_ndxscn(next->scn)); - source->shdr_info[elf_ndxscn(next->scn)].idx = 0; - dropped_sections = true; -#endif - } - - while (++next_idx < num_scns) { - next = (section_info_t *)scns[next_idx].user; -#ifdef REMOVE_HANDLED_SECTIONS - ASSERT(next->info == NULL || - next->shdr.sh_name == next->info->old_shdr.sh_name); - const char *sname = - elf_strptr(source->oldelf, - source->shstrndx, - next->shdr.sh_name); - INFO("\tsection [%s] (index %d) is now empty, marking for " - "removal.\n", - sname, - elf_ndxscn(next->scn)); - /* mark for removal */ - source->shdr_info[elf_ndxscn(next->scn)].idx = 0; - dropped_sections = true; -#endif - } - } - - } /* if (dyn->sections) */ - else { - /* The dynamic entry won't have any sections when it itself doesn't - exist. This could happen when we remove all relocation sections - from a dynamic entry because we have managed to handle all - relocations in them. - */ - INFO("\tNo section for dynamic entry!\n"); - } - - return dropped_sections; -} - -static bool adjust_dynamic_segment(source_t *source, - bool adjust_section_size_only) -{ - bool dropped_section; - INFO("Adjusting dynamic segment%s.\n", - (adjust_section_size_only ? " (section sizes only)" : "")); - INFO("\tadjusting dynamic segment REL.\n"); - dropped_section = - adjust_dynamic_segment_for(source, &source->rel, - adjust_section_size_only); - INFO("\tadjusting dynamic segment JMPREL.\n"); - dropped_section = - adjust_dynamic_segment_for(source, &source->jmprel, - adjust_section_size_only) || - dropped_section; - if (!adjust_section_size_only) - adjust_dynamic_segment_entries(source); - return dropped_section; -} - -static void match_relocation_sections_to_dynamic_ranges(source_t *source) -{ - /* We've gathered all the DT_DYNAMIC entries; now we need to figure out - which relocation sections fit in which range as described by the - entries. - */ - - int relidx; - for (relidx = 0; relidx < source->num_relocation_sections; relidx++) { - section_info_t *reloc_scn = &source->relocation_sections[relidx]; - - int index = elf_ndxscn(reloc_scn->scn); - - ASSERT(reloc_scn->info == NULL || - reloc_scn->shdr.sh_name == reloc_scn->info->old_shdr.sh_name); - const char *sname = - elf_strptr(source->oldelf, - source->shstrndx, - reloc_scn->shdr.sh_name); - - INFO("Checking section [%s], index %d, for match to dynamic ranges\n", - sname, index); - if (source->shdr_info == NULL || reloc_scn->info->idx > 0) { - if (source->rel.addr && - source->rel.addr <= reloc_scn->shdr.sh_addr && - reloc_scn->shdr.sh_addr < source->rel.addr + source->rel.size) - { - /* The entire section must fit in the dynamic range. */ - if((reloc_scn->shdr.sh_addr + reloc_scn->shdr.sh_size) > - (source->rel.addr + source->rel.size)) - { - PRINT("WARNING: In [%s], section %s:[%lld,%lld) " - "is not fully contained in dynamic range " - "[%lld,%lld)!\n", - source->name, - sname, - reloc_scn->shdr.sh_addr, - reloc_scn->shdr.sh_addr + - reloc_scn->shdr.sh_size, - source->rel.addr, - source->rel.addr + source->rel.size); - } - - if (NULL == source->rel.sections) { - source->rel.sections = init_range_list(); - ASSERT(source->rel.sections); - } - add_unique_range_nosort(source->rel.sections, - reloc_scn->shdr.sh_addr, - reloc_scn->shdr.sh_size, - reloc_scn, - NULL, - NULL); - INFO("\tSection [%s] matches dynamic range REL.\n", - sname); - } - else if (source->jmprel.addr && - source->jmprel.addr <= reloc_scn->shdr.sh_addr && - reloc_scn->shdr.sh_addr <= source->jmprel.addr + - source->jmprel.size) - { - if((reloc_scn->shdr.sh_addr + reloc_scn->shdr.sh_size) > - (source->jmprel.addr + source->jmprel.size)) - { - PRINT("WARNING: In [%s], section %s:[%lld,%lld) " - "is not fully " - "contained in dynamic range [%lld,%lld)!\n", - source->name, - sname, - reloc_scn->shdr.sh_addr, - reloc_scn->shdr.sh_addr + - reloc_scn->shdr.sh_size, - source->jmprel.addr, - source->jmprel.addr + source->jmprel.size); - } - - if (NULL == source->jmprel.sections) { - source->jmprel.sections = init_range_list(); - ASSERT(source->jmprel.sections); - } - add_unique_range_nosort(source->jmprel.sections, - reloc_scn->shdr.sh_addr, - reloc_scn->shdr.sh_size, - reloc_scn, - NULL, - NULL); - INFO("\tSection [%s] matches dynamic range JMPREL.\n", - sname); - } - else - PRINT("WARNING: Relocation section [%s:%s] does not match " - "any DT_ entry.\n", - source->name, - sname); - } - else { - INFO("Section [%s] was removed, not matching it to dynamic " - "ranges.\n", - sname); - } - } /* for ... */ - - if (source->rel.sections) sort_ranges(source->rel.sections); - if (source->jmprel.sections) sort_ranges(source->jmprel.sections); -} - -static void drop_sections(source_t *source) -{ - INFO("We are dropping some sections from [%s]--creating section entries " - "only for remaining sections.\n", - source->name); - /* Renumber the sections. The numbers for the sections after those we are - dropping will be shifted back by the number of dropped sections. */ - int cnt, idx; - for (cnt = idx = 1; cnt < source->shnum; ++cnt) { - if (source->shdr_info[cnt].idx > 0) { - source->shdr_info[cnt].idx = idx++; - - /* Create a new section. */ - FAILIF_LIBELF((source->shdr_info[cnt].newscn = - elf_newscn(source->elf)) == NULL, elf_newscn); - ASSERT(elf_ndxscn (source->shdr_info[cnt].newscn) == - source->shdr_info[cnt].idx); - - /* Copy the section data */ - Elf_Data *olddata = - elf_getdata(source->shdr_info[cnt].scn, // old section - NULL); - FAILIF_LIBELF(NULL == olddata, elf_getdata); - Elf_Data *data = - elf_newdata(source->shdr_info[cnt].newscn); - FAILIF_LIBELF(NULL == data, elf_newdata); - *data = *olddata; -#if COPY_SECTION_DATA_BUFFER - if (olddata->d_buf != NULL) { - data->d_buf = MALLOC(data->d_size); - memcpy(data->d_buf, olddata->d_buf, olddata->d_size); - } -#endif - source->shdr_info[cnt].data = data; - - if (data->d_size != - source->shdr_info[cnt].shdr.sh_size) { - INFO("Trimming new-section data from %d to %lld bytes " - "(as calculated by adjust_dynamic_segment()).\n", - data->d_size, - source->shdr_info[cnt].shdr.sh_size); - data->d_size = - source->shdr_info[cnt].shdr.sh_size; - } - - INFO("\tsection [%s] (old offset %lld, old size %lld) " - "will have index %d (was %d), new size %d\n", - source->shdr_info[cnt].name, - source->shdr_info[cnt].old_shdr.sh_offset, - source->shdr_info[cnt].old_shdr.sh_size, - source->shdr_info[cnt].idx, - elf_ndxscn(source->shdr_info[cnt].scn), - data->d_size); - } else { - INFO("\tIgnoring section [%s] (offset %lld, size %lld, index %d), " - "it will be discarded.\n", - source->shdr_info[cnt].name, - source->shdr_info[cnt].shdr.sh_offset, - source->shdr_info[cnt].shdr.sh_size, - elf_ndxscn(source->shdr_info[cnt].scn)); - } - - /* NOTE: We mark use_old_shdr_for_relocation_calculations even for the - sections we are removing. adjust_elf has an assertion that makes - sure that if the values for the size of a section according to its - header and its data structure differ, then we are using explicitly - the old section header for calculations, and that the section in - question is a relocation section. - */ - source->shdr_info[cnt].use_old_shdr_for_relocation_calculations = true; - } /* for */ -} - -static source_t* process_file(const char *filename, - const char *output, int is_file, - void (*report_library_size_in_memory)( - const char *name, off_t fsize), - unsigned (*get_next_link_address)( - const char *name), - int locals_only, - char **lib_lookup_dirs, - int num_lib_lookup_dirs, - char **default_libs, - int num_default_libs, - int dry_run, - int *total_num_handled_relocs, - int *total_num_unhandled_relocs) -{ - /* Look up the file in the list of already-handles files, which are - represented by source_t structs. If we do not find the file, then we - haven't prelinked it yet. If we find it, then we have, so we do - nothing. Keep in mind that apriori operates on an entire collection - of files, and if application A used library L, and so does application - B, if we process A first, then by the time we get to B we will have - prelinked L already; that's why we check first to see if a library has - been prelinked. - */ - source_t *source = - find_source(filename, lib_lookup_dirs, num_lib_lookup_dirs); - if (NULL == source) { - /* If we could not find the source, then it hasn't been processed yet, - so we go ahead and process it! */ - INFO("Processing [%s].\n", filename); - char *full = find_file(filename, lib_lookup_dirs, num_lib_lookup_dirs); - FAILIF(NULL == full, - "Could not find [%s] in the current directory or in any of " - "the search paths!\n", filename); - - unsigned base = get_next_link_address(full); - - source = init_source(full, output, is_file, base, dry_run); - - if (source == NULL) { - INFO("File [%s] is a static executable.\n", filename); - return NULL; - } - ASSERT(source->dynamic.scn != NULL); - - /* We need to increment the next prelink address only when the file we - are currently handing is a shared library. Executables do not need - to be prelinked at a different address, they are always at address - zero. - - Also, if we are prelinking locals only, then we are handling a - single file per invokation of apriori, so there is no need to - increment the prelink address unless there is a global prelink map, - in which case we do need to check to see if the library isn't - running into its neighbouts in the prelink map. - */ - if (source->oldelf_hdr.e_type != ET_EXEC && - (!locals_only || - report_library_size_in_memory == - pm_report_library_size_in_memory)) { - /* This sets the next link address only if an increment was not - specified by the user. If an address increment was specified, - then we just check to make sure that the file size is less than - the increment. - - NOTE: The file size is the absolute highest number of bytes that - the file may occupy in memory, if the entire file is loaded, but - this is almost next the case. A file will often have sections - which are not loaded, which could add a lot of size. That's why - we start off with the file size and then subtract the size of - the biggest sections that will not get loaded, which are the - varios DWARF sections, all of which of which are named starting - with ".debug_". - - We could do better than this (by caculating exactly how many - bytes from that file will be loaded), but that's an overkill. - Unless the prelink-address increment becomes too small, the file - size after subtracting the sizes of the DWARF section will be a - good-enough upper bound. - */ - - unsigned long fsize = source->elf_file_info.st_size; - INFO("Calculating loadable file size for next link address. " - "Starting with %ld.\n", fsize); - if (true) { - Elf_Scn *scn = NULL; - GElf_Shdr shdr_mem, *shdr; - const char *scn_name; - while ((scn = elf_nextscn (source->oldelf, scn)) != NULL) { - shdr = gelf_getshdr(scn, &shdr_mem); - FAILIF_LIBELF(NULL == shdr, gelf_getshdr); - scn_name = elf_strptr (source->oldelf, - source->shstrndx, shdr->sh_name); - ASSERT(scn_name != NULL); - - if (!(shdr->sh_flags & SHF_ALLOC)) { - INFO("\tDecrementing by %lld on account of section " - "[%s].\n", - shdr->sh_size, - scn_name); - fsize -= shdr->sh_size; - } - } - } - INFO("Done calculating loadable file size for next link address: " - "Final value is %ld.\n", fsize); - report_library_size_in_memory(source->name, fsize); - } - - /* Identify the dynamic segment and process it. Specifically, we find - out what dependencies, if any, this file has. Whenever we encounter - such a dependency, we process it recursively; we find out where the - various relocation information sections are stored. */ - - size_t dynidx; - GElf_Dyn *dyn, dyn_mem; - size_t numdyn = - source->dynamic.shdr.sh_size / - source->dynamic.shdr.sh_entsize; - ASSERT(source->dynamic.shdr.sh_size == source->dynamic.data->d_size); - - source->rel.idx = source->rel.sz_idx = -1; - source->jmprel.idx = source->jmprel.sz_idx = -1; - - for (dynidx = 0; dynidx < numdyn; dynidx++) { - dyn = gelf_getdyn (source->dynamic.data, - dynidx, - &dyn_mem); - FAILIF_LIBELF(NULL == dyn, gelf_getdyn); - /* When we are processing only the local relocations in a file, - we don't need to handle any of the dependencies. It won't - hurt if we do, but we will be doing unnecessary work. - */ - switch (dyn->d_tag) - { - case DT_NEEDED: - if (!locals_only) { - /* Process the needed library recursively. - */ - const char *dep_lib = -#if ELF_STRPTR_IS_BROKEN - (((char *)elf_getdata( - elf_getscn(source->elf, - source->dynamic.shdr.sh_link), - NULL)->d_buf) + dyn->d_un.d_val); -#else - elf_strptr (source->elf, - source->dynamic.shdr.sh_link, - dyn->d_un.d_val); -#endif - ASSERT(dep_lib != NULL); - INFO("[%s] depends on [%s].\n", filename, dep_lib); - ASSERT(output == NULL || is_file == 0); - source_t *dep = process_file(dep_lib, - output, is_file, - report_library_size_in_memory, - get_next_link_address, - locals_only, - lib_lookup_dirs, - num_lib_lookup_dirs, - default_libs, - num_default_libs, - dry_run, - total_num_handled_relocs, - total_num_unhandled_relocs); - - /* Add the library to the dependency list. */ - if (source->num_lib_deps == source->lib_deps_size) { - source->lib_deps_size += 10; - source->lib_deps = REALLOC(source->lib_deps, - source->lib_deps_size * - sizeof(source_t *)); - } - source->lib_deps[source->num_lib_deps++] = dep; - } - break; - case DT_JMPREL: - source->jmprel.idx = dynidx; - source->jmprel.addr = dyn->d_un.d_ptr; - break; - case DT_PLTRELSZ: - source->jmprel.sz_idx = dynidx; - source->jmprel.size = dyn->d_un.d_val; - break; - case DT_REL: - source->rel.idx = dynidx; - source->rel.addr = dyn->d_un.d_ptr; - break; - case DT_RELSZ: - source->rel.sz_idx = dynidx; - source->rel.size = dyn->d_un.d_val; - break; - case DT_RELA: - case DT_RELASZ: - FAILIF(1, "Can't handle DT_RELA and DT_RELASZ entries!\n"); - break; - } /* switch */ - } /* for each dynamic entry... */ - - INFO("Handling [%s].\n", filename); - -#ifdef SUPPORT_ANDROID_PRELINK_TAGS - if (!source->prelinked) -#endif - { - /* When ADJUST_ELF is defined, this call to prelink is a dry run - intended to calculate the number of relocations that could not - be handled. This, in turn, allows us to calculate the amount by - which we can shrink the various relocation sections before we - call adjust_elf. After we've adjusted the sections, we will - call prelink() one more time to do the actual work. - - NOTE: Even when ADJUST_ELF != 0, we cannot adjust an ELF file - that is an executabe, because an executable is not PIC. - */ - - int num_unfinished_relocs = 0; - bool adjust_file = ADJUST_ELF && source->elf_hdr.e_type != ET_EXEC; - INFO("\n\n\tPRELINKING %s\n\n", - adjust_file ? - "(CALCULATE NUMBER OF HANDLED RELOCATIONS)" : - "(ACTUAL)"); - int num_relocs = prelink(source, locals_only, - adjust_file || dry_run, - lib_lookup_dirs, num_lib_lookup_dirs, - default_libs, num_default_libs, - &num_unfinished_relocs); - INFO("[%s]: (calculate changes) handled %d, could not handle %d " - "relocations.\n", - source->name, - num_relocs, - num_unfinished_relocs); - - if (adjust_file && !dry_run) - { - /* Find out the new section sizes of the relocation sections, - but do not move any relocations around, because adjust_elf - needs to know about all relocations in order to adjust the - file correctly. - */ - match_relocation_sections_to_dynamic_ranges(source); - - /* We haven't set up source->shdr_info[] yet, so we do it now. - - NOTE: setup_shdr_info() depends only on source->oldelf, not - on source->elf! source->elf is not even defined yet. We - initialize source->shdr_info[] based on the section - information of the unmodified ELF file, and then make our - modifications in the call to adjust_dynamic_segment() based - on this information. adjust_dynamic_segment() will - rearrange the unhandled relocations in the beginning of - their relocation sections, and adjust the size of those - relocation sections. In the case when a relocation section - is completely handled, adjust_dynamic_segment() will mark it - for removal by function adjust_elf. - */ - - ASSERT(source->elf == source->oldelf); - ASSERT(source->shdr_info == NULL); - setup_shdr_info(source); - ASSERT(source->shdr_info != NULL); - - INFO("\n\n\tADJUSTING DYNAMIC SEGMENT " - "(CALCULATE CHANGES)\n\n"); - bool drop_some_sections = adjust_dynamic_segment(source, true); - - /* Reopen the elf file! Note that we are not doing a dry run - (the if statement above makes sure of that.) - - NOTE: We call init_elf() after we called - adjust_dynamic_segment() in order to have - adjust_dynamic_segment() refer to source->oldelf when - it refers to source->elf. Since - adjust_dynamic_segment doesn't actually write to the - ELF file, this is OK. adjust_dynamic_segment() - updates the sh_size fields of saved section headers - and optionally marks sections for removal. - - Having adjust_dynamic_segment() refer to - source->oldelf means that we'll have access to - section-name strings so we can print them out in our - logging and debug output. - */ - source->elf = init_elf(source, false); - - /* This is the same code as in init_source() after the call to - * init_elf(). */ - ASSERT(source->elf != source->oldelf); - ebl_closebackend(source->ebl); - source->ebl = ebl_openbackend (source->elf); - FAILIF_LIBELF(NULL == source->ebl, ebl_openbackend); -#ifdef ARM_SPECIFIC_HACKS - FAILIF_LIBELF(0 != arm_init(source->elf, - source->elf_hdr.e_machine, - source->ebl, sizeof(Ebl)), - arm_init); -#endif/*ARM_SPECIFIC_HACKS*/ - - if (drop_some_sections) - drop_sections(source); - else { - INFO("All sections remain in [%s]--we are changing at " - "most section sizes.\n", source->name); - create_elf_sections(source, NULL); - int cnt, idx; - for (cnt = idx = 1; cnt < source->shnum; ++cnt) { - Elf_Data *data = elf_getdata( - source->shdr_info[cnt].newscn, // new section - NULL); - if (data->d_size != - source->shdr_info[cnt].shdr.sh_size) { - INFO("Trimming new-section data from %d to %lld " - "bytes (as calculated by " - "adjust_dynamic_segment()).\n", - data->d_size, - source->shdr_info[cnt].shdr.sh_size); - data->d_size = source->shdr_info[cnt].shdr.sh_size; - } - } - } - - /* Shrink it! */ - INFO("\n\n\tADJUSTING ELF\n\n"); - adjust_elf( - source->oldelf, source->name, - source->elf, source->name, - source->ebl, - &source->old_ehdr_mem, - NULL, 0, // no symbol filter - source->shdr_info, // information on how to adjust the ELF - source->shnum, // length of source->shdr_info[] - source->phdr_info, // program-header info - source->shnum, // irrelevant--we're not rebuilding shstrtab - source->shnum, // number of sections in file - source->shstrndx, // index of shstrtab (both in - // shdr_info[] and as a section index) - NULL, // irrelevant, since we are not rebuilding shstrtab - drop_some_sections, // some sections are being dropped - elf_ndxscn(source->dynamic.scn), // index of .dynamic - elf_ndxscn(source->symtab.scn), // index of .dynsym - 1, // allow shady business - &source->shstrtab_data, - true, - false); // do not rebuild shstrtab - - INFO("\n\n\tREINITIALIZING STRUCTURES " - "(TO CONTAIN ADJUSTMENTS)\n\n"); - reinit_source(source); - - INFO("\n\n\tPRELINKING (ACTUAL)\n\n"); -#ifdef DEBUG - int old_num_unfinished_relocs = num_unfinished_relocs; -#endif - num_unfinished_relocs = 0; -#ifdef DEBUG - int num_relocs_take_two = -#endif - prelink(source, locals_only, - false, /* not a dry run */ - lib_lookup_dirs, num_lib_lookup_dirs, - default_libs, num_default_libs, - &num_unfinished_relocs); - - /* The numbers for the total number of relocations and the - number of unhandled relocations between the first and second - invokationof prelink() must be the same! The first time we - ran prelink() just to calculate the numbers so that we could - calculate the adjustments to pass to adjust_elf, and the - second time we actually carry out the prelinking; the - numbers must stay the same! - */ - ASSERT(num_relocs == num_relocs_take_two); - ASSERT(old_num_unfinished_relocs == num_unfinished_relocs); - - INFO("[%s]: (actual prelink) handled %d, could not " - "handle %d relocations.\n", - source->name, - num_relocs, - num_unfinished_relocs); - } /* if (adjust_elf && !dry_run) */ - - *total_num_handled_relocs += num_relocs; - *total_num_unhandled_relocs += num_unfinished_relocs; - - if(num_unfinished_relocs != 0 && - source->elf_hdr.e_type != ET_EXEC && - !locals_only) - { - /* One reason you could have unfinished relocations in an - executable file is if this file used dlopen() and friends. - We do not adjust relocation entries to those symbols, - because libdl is a dummy only--the real functions are - provided for by the dynamic linker itsef. - - NOTE FIXME HACK: This is specific to the Android dynamic - linker, and may not be true in other cases. - */ - PRINT("WARNING: Expecting to have unhandled relocations only " - "for executables (%s is not an executable)!\n", - source->name); - } - - match_relocation_sections_to_dynamic_ranges(source); - - /* Now, for each relocation section, check to see if its address - matches one of the DT_DYNAMIC relocation pointers. If so, then - if the section has no unhandled relocations, simply set the - associated DT_DYNAMIC entry's size to zero. If the section does - have unhandled entries, then lump them all together at the front - of the respective section and update the size of the respective - DT_DYNAMIC entry to the new size of the section. A better - approach would be do delete a relocation section if it has been - fully relocated and to remove its entry from the DT_DYNAMIC - array, and for relocation entries that still have some - relocations in them, we should shrink the section if that won't - violate relative offsets. This is more work, however, and for - the speed improvement we expect from a prelinker, just patching - up DT_DYNAMIC will suffice. - - Note: adjust_dynamic_segment() will modify source->shdr_info[] - to denote any change in a relocation section's size. This - will be picked up by adjust_elf, which will rearrange the - file to eliminate the gap created by the decrease in size - of the relocation section. We do not need to do this, but - the relocation section could be large, and reduced - drastically by the prelinking process, so it pays to - adjust the file. - */ - - INFO("\n\n\tADJUSTING DYNAMIC SEGMENT (ACTUAL)\n\n"); - adjust_dynamic_segment(source, false); - } -#ifdef SUPPORT_ANDROID_PRELINK_TAGS - else INFO("[%s] is already prelinked at 0x%08lx.\n", - filename, - source->prelink_base); -#endif - } else INFO("[%s] has been processed already.\n", filename); - - return source; -} - -void apriori(char **execs, int num_execs, - char *output, - void (*report_library_size_in_memory)( - const char *name, off_t fsize), - int (*get_next_link_address)(const char *name), - int locals_only, - int dry_run, - char **lib_lookup_dirs, int num_lib_lookup_dirs, - char **default_libs, int num_default_libs, - char *mapfile) -{ - source_t *source; /* for general usage */ - int input_idx; - - ASSERT(report_library_size_in_memory != NULL); - ASSERT(get_next_link_address != NULL); - - /* Process and prelink each executable and object file. Function - process_file() is called for each executable in the loop below. - It calls itself recursively for each library. We prelink each library - after prelinking its dependencies. */ - int total_num_handled_relocs = 0, total_num_unhandled_relocs = 0; - for (input_idx = 0; input_idx < num_execs; input_idx++) { - INFO("executable: [%s]\n", execs[input_idx]); - /* Here process_file() is actually processing the top-level - executable files. */ - process_file(execs[input_idx], output, num_execs == 1, - report_library_size_in_memory, - get_next_link_address, /* executables get a link address - of zero, regardless of this - value */ - locals_only, - lib_lookup_dirs, num_lib_lookup_dirs, - default_libs, num_default_libs, - dry_run, - &total_num_handled_relocs, - &total_num_unhandled_relocs); - /* if source is NULL, then the respective executable is static */ - /* Mark the source as an executable */ - } /* for each input executable... */ - - PRINT("Handled %d relocations.\n", total_num_handled_relocs); - PRINT("Could not handle %d relocations.\n", total_num_unhandled_relocs); - - /* We are done! Since the end result of our calculations is a set of - symbols for each library that other libraries or executables link - against, we iterate over the set of libraries one last time, and for - each symbol that is marked as satisfying some dependence, we emit - a line with the symbol's name to a text file derived from the library's - name by appending the suffix .syms to it. */ - - if (mapfile != NULL) { - const char *mapfile_name = mapfile; - FILE *fp; - if (*mapfile == '+') { - mapfile_name = mapfile + 1; - INFO("Opening map file %s for append/write.\n", - mapfile_name); - fp = fopen(mapfile_name, "a"); - } - else fp = fopen(mapfile_name, "w"); - - FAILIF(fp == NULL, "Cannot open file [%s]: %s (%d)!\n", - mapfile_name, - strerror(errno), - errno); - source = sources; - while (source) { - /* If it's a library, print the results. */ - if (source->elf_hdr.e_type == ET_DYN) { - /* Add to the memory map file. */ - fprintf(fp, "%s 0x%08lx %lld\n", - basename(source->name), - source->base, - source->elf_file_info.st_size); - } - source = source->next; - } - fclose(fp); - } - - /* Free the resources--you can't do it in the loop above because function - print_symbol_references() accesses nodes other than the one being - iterated over. - */ - source = sources; - while (source) { - source_t *old = source; - source = source->next; - /* Destroy the evidence. */ - destroy_source(old); - } -} |