summaryrefslogtreecommitdiffstats
path: root/libcorkscrew
diff options
context:
space:
mode:
Diffstat (limited to 'libcorkscrew')
-rw-r--r--libcorkscrew/Android.mk57
-rw-r--r--libcorkscrew/arch-arm/ptrace-arm.c11
-rw-r--r--libcorkscrew/arch-mips/backtrace-mips.c11
-rwxr-xr-x[-rw-r--r--]libcorkscrew/arch-x86/backtrace-x86.c765
-rwxr-xr-xlibcorkscrew/arch-x86/dwarf.h140
-rwxr-xr-x[-rw-r--r--]libcorkscrew/arch-x86/ptrace-x86.c39
-rw-r--r--libcorkscrew/backtrace.c31
-rw-r--r--libcorkscrew/map_info.c12
-rwxr-xr-x[-rw-r--r--]libcorkscrew/ptrace-arch.h2
-rw-r--r--libcorkscrew/ptrace.c2
-rw-r--r--libcorkscrew/symbol_table.c12
-rw-r--r--libcorkscrew/test.c64
12 files changed, 1089 insertions, 57 deletions
diff --git a/libcorkscrew/Android.mk b/libcorkscrew/Android.mk
index aace5f8..2786d8f 100644
--- a/libcorkscrew/Android.mk
+++ b/libcorkscrew/Android.mk
@@ -14,9 +14,7 @@
LOCAL_PATH:= $(call my-dir)
-include $(CLEAR_VARS)
-
-LOCAL_SRC_FILES := \
+generic_src_files := \
backtrace.c \
backtrace-helper.c \
demangle.c \
@@ -24,16 +22,24 @@ LOCAL_SRC_FILES := \
ptrace.c \
symbol_table.c
-ifeq ($(TARGET_ARCH),arm)
-LOCAL_SRC_FILES += \
+arm_src_files := \
arch-arm/backtrace-arm.c \
arch-arm/ptrace-arm.c
+
+x86_src_files := \
+ arch-x86/backtrace-x86.c \
+ arch-x86/ptrace-x86.c
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(generic_src_files)
+
+ifeq ($(TARGET_ARCH),arm)
+LOCAL_SRC_FILES += $(arm_src_files)
LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
endif
ifeq ($(TARGET_ARCH),x86)
-LOCAL_SRC_FILES += \
- arch-x86/backtrace-x86.c \
- arch-x86/ptrace-x86.c
+LOCAL_SRC_FILES += $(x86_src_files)
LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
endif
ifeq ($(TARGET_ARCH),mips)
@@ -50,3 +56,38 @@ LOCAL_MODULE := libcorkscrew
LOCAL_MODULE_TAGS := optional
include $(BUILD_SHARED_LIBRARY)
+
+# Build test.
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := test.c
+LOCAL_CFLAGS += -std=gnu99 -Werror -fno-inline-small-functions
+LOCAL_SHARED_LIBRARIES := libcorkscrew
+LOCAL_MODULE := libcorkscrew_test
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_EXECUTABLE)
+
+
+ifeq ($(HOST_OS)-$(HOST_ARCH),linux-x86)
+
+# Build libcorkscrew.
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES += $(generic_src_files) $(x86_src_files)
+LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
+LOCAL_SHARED_LIBRARIES += libgccdemangle
+LOCAL_STATIC_LIBRARIES += libcutils
+LOCAL_LDLIBS += -ldl -lrt
+LOCAL_CFLAGS += -std=gnu99 -Werror
+LOCAL_MODULE := libcorkscrew
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_HOST_SHARED_LIBRARY)
+
+# Build test.
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := test.c
+LOCAL_CFLAGS += -std=gnu99 -Werror -fno-inline-small-functions
+LOCAL_SHARED_LIBRARIES := libcorkscrew
+LOCAL_MODULE := libcorkscrew_test
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_HOST_EXECUTABLE)
+
+endif # linux-x86
diff --git a/libcorkscrew/arch-arm/ptrace-arm.c b/libcorkscrew/arch-arm/ptrace-arm.c
index 868230c..78a9ea9 100644
--- a/libcorkscrew/arch-arm/ptrace-arm.c
+++ b/libcorkscrew/arch-arm/ptrace-arm.c
@@ -29,12 +29,15 @@
static void load_exidx_header(pid_t pid, map_info_t* mi,
uintptr_t* out_exidx_start, size_t* out_exidx_size) {
uint32_t elf_phoff;
- uint32_t elf_phentsize_phnum;
+ uint32_t elf_phentsize_ehsize;
+ uint32_t elf_shentsize_phnum;
if (try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff)
+ && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_ehsize),
+ &elf_phentsize_ehsize)
&& try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum),
- &elf_phentsize_phnum)) {
- uint32_t elf_phentsize = elf_phentsize_phnum >> 16;
- uint32_t elf_phnum = elf_phentsize_phnum & 0xffff;
+ &elf_shentsize_phnum)) {
+ uint32_t elf_phentsize = elf_phentsize_ehsize >> 16;
+ uint32_t elf_phnum = elf_shentsize_phnum & 0xffff;
for (uint32_t i = 0; i < elf_phnum; i++) {
uintptr_t elf_phdr = mi->start + elf_phoff + i * elf_phentsize;
uint32_t elf_phdr_type;
diff --git a/libcorkscrew/arch-mips/backtrace-mips.c b/libcorkscrew/arch-mips/backtrace-mips.c
index 07d4a24..1abdd83 100644
--- a/libcorkscrew/arch-mips/backtrace-mips.c
+++ b/libcorkscrew/arch-mips/backtrace-mips.c
@@ -90,7 +90,8 @@ static ssize_t unwind_backtrace_common(const memory_t* memory,
if (frame)
frame->stack_top = state->sp;
- ALOGV("#%d: frame=%p pc=%08x sp=%08x\n", index, frame, frame->absolute_pc, frame->stack_top);
+ ALOGV("#%d: frame=%p pc=%08x sp=%08x\n",
+ index, frame, frame->absolute_pc, frame->stack_top);
for (addr = state->pc; maxcheck-- > 0 && !found_start; addr -= 4) {
uint32_t op;
@@ -115,7 +116,7 @@ static ssize_t unwind_backtrace_common(const memory_t* memory,
ALOGV("@0x%08x: found ra offset=%d\n", addr, ra_offset);
break;
case 0x3c1c0000: // lui gp
- ALOGV("@0x%08x: found function boundary\n", addr);
+ ALOGV("@0x%08x: found function boundary\n", addr);
found_start = true;
break;
default:
@@ -162,7 +163,8 @@ ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext,
state.pc = uc->pc;
state.ra = uc->ra;
- ALOGV("unwind_backtrace_signal_arch: ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n",
+ ALOGV("unwind_backtrace_signal_arch: "
+ "ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n",
ignore_depth, max_depth, state.pc, state.sp, state.ra);
memory_t memory;
@@ -184,7 +186,8 @@ ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
state.ra = regs.regs[31];
state.pc = regs.epc;
- ALOGV("unwind_backtrace_ptrace_arch: ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n",
+ ALOGV("unwind_backtrace_ptrace_arch: "
+ "ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n",
ignore_depth, max_depth, state.pc, state.sp, state.ra);
memory_t memory;
diff --git a/libcorkscrew/arch-x86/backtrace-x86.c b/libcorkscrew/arch-x86/backtrace-x86.c
index 082f635..29159ed 100644..100755
--- a/libcorkscrew/arch-x86/backtrace-x86.c
+++ b/libcorkscrew/arch-x86/backtrace-x86.c
@@ -23,18 +23,30 @@
#include "../backtrace-arch.h"
#include "../backtrace-helper.h"
+#include "../ptrace-arch.h"
#include <corkscrew/ptrace.h>
+#include "dwarf.h"
#include <stdlib.h>
#include <signal.h>
#include <stdbool.h>
#include <limits.h>
#include <errno.h>
+#include <string.h>
#include <sys/ptrace.h>
-#include <sys/exec_elf.h>
#include <cutils/log.h>
-#if !defined(__BIONIC_HAVE_UCONTEXT_T)
+#if defined(__BIONIC__)
+
+#if defined(__BIONIC_HAVE_UCONTEXT_T)
+
+// Bionic offers the Linux kernel headers.
+#include <asm/sigcontext.h>
+#include <asm/ucontext.h>
+typedef struct ucontext ucontext_t;
+
+#else /* __BIONIC_HAVE_UCONTEXT_T */
+
/* Old versions of the Android <signal.h> didn't define ucontext_t. */
typedef struct {
@@ -60,47 +72,744 @@ typedef struct ucontext {
mcontext_t uc_mcontext;
uint32_t uc_sigmask;
} ucontext_t;
-#endif /* !__BIONIC_HAVE_UCONTEXT_T */
+
+#endif /* __BIONIC_HAVE_UCONTEXT_T */
+
+#else /* __BIONIC__ */
+
+// glibc has its own renaming of the Linux kernel's structures.
+#define __USE_GNU // For REG_EBP, REG_ESP, and REG_EIP.
+#include <ucontext.h>
+
+#endif /* __ BIONIC__ */
/* Unwind state. */
typedef struct {
- uint32_t ebp;
- uint32_t eip;
- uint32_t esp;
+ uint32_t reg[DWARF_REGISTERS];
} unwind_state_t;
+typedef struct {
+ backtrace_frame_t* backtrace;
+ size_t ignore_depth;
+ size_t max_depth;
+ size_t ignored_frames;
+ size_t returned_frames;
+ memory_t memory;
+} backtrace_state_t;
+
uintptr_t rewind_pc_arch(const memory_t* memory __attribute__((unused)), uintptr_t pc) {
- // TODO: Implement for x86.
- return pc;
+ /* TODO: x86 instructions are 1-16 bytes, to define exact size of previous instruction
+ we have to disassemble from the function entry point up to pc.
+ Returning pc-1 is probably enough for now, the only drawback is that
+ it points somewhere between the first byte of instruction we are looking for and
+ the first byte of the next instruction. */
+
+ return pc-1;
+ /* TODO: We should adjust that for the signal frames and return pc for them instead of pc-1.
+ To recognize signal frames we should read cie_info property. */
+}
+
+/* Read byte through 4 byte cache. Usually we read byte by byte and updating cursor. */
+static bool try_get_byte(const memory_t* memory, uintptr_t ptr, uint8_t* out_value, uint32_t* cursor) {
+ static uintptr_t lastptr;
+ static uint32_t buf;
+
+ ptr += *cursor;
+
+ if (ptr < lastptr || lastptr + 3 < ptr) {
+ lastptr = (ptr >> 2) << 2;
+ if (!try_get_word(memory, lastptr, &buf)) {
+ return false;
+ }
+ }
+ *out_value = (uint8_t)((buf >> ((ptr & 3) * 8)) & 0xff);
+ ++*cursor;
+ return true;
+}
+
+/* Getting X bytes. 4 is maximum for now. */
+static bool try_get_xbytes(const memory_t* memory, uintptr_t ptr, uint32_t* out_value, uint8_t bytes, uint32_t* cursor) {
+ uint32_t data = 0;
+ if (bytes > 4) {
+ ALOGE("can't read more than 4 bytes, trying to read %d", bytes);
+ return false;
+ }
+ for (int i = 0; i < bytes; i++) {
+ uint8_t buf;
+ if (!try_get_byte(memory, ptr, &buf, cursor)) {
+ return false;
+ }
+ data |= (uint32_t)buf << (i * 8);
+ }
+ *out_value = data;
+ return true;
+}
+
+/* Reads signed/unsigned LEB128 encoded data. From 1 to 4 bytes. */
+static bool try_get_leb128(const memory_t* memory, uintptr_t ptr, uint32_t* out_value, uint32_t* cursor, bool sign_extend) {
+ uint8_t buf = 0;
+ uint32_t val = 0;
+ uint8_t c = 0;
+ do {
+ if (!try_get_byte(memory, ptr, &buf, cursor)) {
+ return false;
+ }
+ val |= ((uint32_t)buf & 0x7f) << (c * 7);
+ c++;
+ } while (buf & 0x80 && (c * 7) <= 32);
+ if (c * 7 > 32) {
+ ALOGE("%s: data exceeds expected 4 bytes maximum", __FUNCTION__);
+ return false;
+ }
+ if (sign_extend) {
+ if (buf & 0x40) {
+ val |= ((uint32_t)-1 << (c * 7));
+ }
+ }
+ *out_value = val;
+ return true;
+}
+
+/* Reads signed LEB128 encoded data. From 1 to 4 bytes. */
+static bool try_get_sleb128(const memory_t* memory, uintptr_t ptr, uint32_t* out_value, uint32_t* cursor) {
+ return try_get_leb128(memory, ptr, out_value, cursor, true);
+}
+
+/* Reads unsigned LEB128 encoded data. From 1 to 4 bytes. */
+static bool try_get_uleb128(const memory_t* memory, uintptr_t ptr, uint32_t* out_value, uint32_t* cursor) {
+ return try_get_leb128(memory, ptr, out_value, cursor, false);
+}
+
+/* Getting data encoded by dwarf encodings. */
+static bool read_dwarf(const memory_t* memory, uintptr_t ptr, uint32_t* out_value, uint8_t encoding, uint32_t* cursor) {
+ uint32_t data = 0;
+ bool issigned = true;
+ uintptr_t addr = ptr + *cursor;
+ /* Lower 4 bits is data type/size */
+ /* TODO: add more encodings if it becomes necessary */
+ switch (encoding & 0xf) {
+ case DW_EH_PE_absptr:
+ if (!try_get_xbytes(memory, ptr, &data, 4, cursor)) {
+ return false;
+ }
+ *out_value = data;
+ return true;
+ case DW_EH_PE_udata4:
+ issigned = false;
+ case DW_EH_PE_sdata4:
+ if (!try_get_xbytes(memory, ptr, &data, 4, cursor)) {
+ return false;
+ }
+ break;
+ default:
+ ALOGE("unrecognized dwarf lower part encoding: 0x%x", encoding);
+ return false;
+ }
+ /* Higher 4 bits is modifier */
+ /* TODO: add more encodings if it becomes necessary */
+ switch (encoding & 0xf0) {
+ case 0:
+ *out_value = data;
+ break;
+ case DW_EH_PE_pcrel:
+ if (issigned) {
+ *out_value = addr + (int32_t)data;
+ } else {
+ *out_value = addr + data;
+ }
+ break;
+ /* Assuming ptr is correct base to calculate datarel */
+ case DW_EH_PE_datarel:
+ if (issigned) {
+ *out_value = ptr + (int32_t)data;
+ } else {
+ *out_value = ptr + data;
+ }
+ break;
+ default:
+ ALOGE("unrecognized dwarf higher part encoding: 0x%x", encoding);
+ return false;
+ }
+ return true;
+}
+
+/* Having PC find corresponding FDE by reading .eh_frame_hdr section data. */
+static uintptr_t find_fde(const memory_t* memory,
+ const map_info_t* map_info_list, uintptr_t pc) {
+ if (!pc) {
+ ALOGV("find_fde: pc is zero, no eh_frame");
+ return 0;
+ }
+ const map_info_t* mi = find_map_info(map_info_list, pc);
+ if (!mi) {
+ ALOGV("find_fde: no map info for pc:0x%x", pc);
+ return 0;
+ }
+ const map_info_data_t* midata = mi->data;
+ if (!midata) {
+ ALOGV("find_fde: no eh_frame_hdr for map: start=0x%x, end=0x%x", mi->start, mi->end);
+ return 0;
+ }
+
+ eh_frame_hdr_info_t eh_hdr_info;
+ memset(&eh_hdr_info, 0, sizeof(eh_frame_hdr_info_t));
+
+ /* Getting the first word of eh_frame_hdr:
+ 1st byte is version;
+ 2nd byte is encoding of pointer to eh_frames;
+ 3rd byte is encoding of count of FDEs in lookup table;
+ 4th byte is encoding of lookup table entries.
+ */
+ uintptr_t eh_frame_hdr = midata->eh_frame_hdr;
+ uint32_t c = 0;
+ if (!try_get_byte(memory, eh_frame_hdr, &eh_hdr_info.version, &c)) return 0;
+ if (!try_get_byte(memory, eh_frame_hdr, &eh_hdr_info.eh_frame_ptr_enc, &c)) return 0;
+ if (!try_get_byte(memory, eh_frame_hdr, &eh_hdr_info.fde_count_enc, &c)) return 0;
+ if (!try_get_byte(memory, eh_frame_hdr, &eh_hdr_info.fde_table_enc, &c)) return 0;
+
+ /* TODO: 3rd byte can be DW_EH_PE_omit, that means no lookup table available and we should
+ try to parse eh_frame instead. Not sure how often it may occur, skipping now.
+ */
+ if (eh_hdr_info.version != 1) {
+ ALOGV("find_fde: eh_frame_hdr version %d is not supported", eh_hdr_info.version);
+ return 0;
+ }
+ /* Getting the data:
+ 2nd word is eh_frame pointer (normally not used, because lookup table has all we need);
+ 3rd word is count of FDEs in the lookup table;
+ starting from 4 word there is FDE lookup table (pairs of PC and FDE pointer) sorted by PC;
+ */
+ if (!read_dwarf(memory, eh_frame_hdr, &eh_hdr_info.eh_frame_ptr, eh_hdr_info.eh_frame_ptr_enc, &c)) return 0;
+ if (!read_dwarf(memory, eh_frame_hdr, &eh_hdr_info.fde_count, eh_hdr_info.fde_count_enc, &c)) return 0;
+ ALOGV("find_fde: found %d FDEs", eh_hdr_info.fde_count);
+
+ int32_t low = 0;
+ int32_t high = eh_hdr_info.fde_count;
+ uintptr_t start = 0;
+ uintptr_t fde = 0;
+ /* eh_frame_hdr + c points to lookup table at this point. */
+ while (low <= high) {
+ uint32_t mid = (high + low)/2;
+ uint32_t entry = c + mid * 8;
+ if (!read_dwarf(memory, eh_frame_hdr, &start, eh_hdr_info.fde_table_enc, &entry)) return 0;
+ if (pc <= start) {
+ high = mid - 1;
+ } else {
+ low = mid + 1;
+ }
+ }
+ /* Value found is at high. */
+ if (high < 0) {
+ ALOGV("find_fde: pc %x is out of FDE bounds: %x", pc, start);
+ return 0;
+ }
+ c += high * 8;
+ if (!read_dwarf(memory, eh_frame_hdr, &start, eh_hdr_info.fde_table_enc, &c)) return 0;
+ if (!read_dwarf(memory, eh_frame_hdr, &fde, eh_hdr_info.fde_table_enc, &c)) return 0;
+ ALOGV("pc 0x%x, ENTRY %d: start=0x%x, fde=0x%x", pc, high, start, fde);
+ return fde;
+}
+
+/* Execute single dwarf instruction and update dwarf state accordingly. */
+static bool execute_dwarf(const memory_t* memory, uintptr_t ptr, cie_info_t* cie_info,
+ dwarf_state_t* dstate, uint32_t* cursor,
+ dwarf_state_t* stack, uint8_t* stack_ptr) {
+ uint8_t inst;
+ uint8_t op = 0;
+
+ if (!try_get_byte(memory, ptr, &inst, cursor)) {
+ return false;
+ }
+ ALOGV("DW_CFA inst: 0x%x", inst);
+
+ /* For some instructions upper 2 bits is opcode and lower 6 bits is operand. See dwarf-2.0 7.23. */
+ if (inst & 0xc0) {
+ op = inst & 0x3f;
+ inst &= 0xc0;
+ }
+
+ switch ((dwarf_CFA)inst) {
+ uint32_t reg = 0;
+ uint32_t offset = 0;
+ case DW_CFA_advance_loc:
+ dstate->loc += op * cie_info->code_align;
+ ALOGV("DW_CFA_advance_loc: %d to 0x%x", op, dstate->loc);
+ break;
+ case DW_CFA_offset:
+ if (!try_get_uleb128(memory, ptr, &offset, cursor)) return false;
+ dstate->regs[op].rule = 'o';
+ dstate->regs[op].value = offset * cie_info->data_align;
+ ALOGV("DW_CFA_offset: r%d = o(%d)", op, dstate->regs[op].value);
+ break;
+ case DW_CFA_restore:
+ dstate->regs[op].rule = stack->regs[op].rule;
+ dstate->regs[op].value = stack->regs[op].value;
+ ALOGV("DW_CFA_restore: r%d = %c(%d)", op, dstate->regs[op].rule, dstate->regs[op].value);
+ break;
+ case DW_CFA_nop:
+ break;
+ case DW_CFA_set_loc: // probably we don't have it on x86.
+ if (!try_get_xbytes(memory, ptr, &offset, 4, cursor)) return false;
+ if (offset < dstate->loc) {
+ ALOGE("DW_CFA_set_loc: attempt to move location backward");
+ return false;
+ }
+ dstate->loc = offset * cie_info->code_align;
+ ALOGV("DW_CFA_set_loc: %d to 0x%x", offset * cie_info->code_align, dstate->loc);
+ break;
+ case DW_CFA_advance_loc1:
+ if (!try_get_byte(memory, ptr, (uint8_t*)&offset, cursor)) return false;
+ dstate->loc += (uint8_t)offset * cie_info->code_align;
+ ALOGV("DW_CFA_advance_loc1: %d to 0x%x", (uint8_t)offset * cie_info->code_align, dstate->loc);
+ break;
+ case DW_CFA_advance_loc2:
+ if (!try_get_xbytes(memory, ptr, &offset, 2, cursor)) return false;
+ dstate->loc += (uint16_t)offset * cie_info->code_align;
+ ALOGV("DW_CFA_advance_loc2: %d to 0x%x", (uint16_t)offset * cie_info->code_align, dstate->loc);
+ break;
+ case DW_CFA_advance_loc4:
+ if (!try_get_xbytes(memory, ptr, &offset, 4, cursor)) return false;
+ dstate->loc += offset * cie_info->code_align;
+ ALOGV("DW_CFA_advance_loc4: %d to 0x%x", offset * cie_info->code_align, dstate->loc);
+ break;
+ case DW_CFA_offset_extended: // probably we don't have it on x86.
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ if (!try_get_uleb128(memory, ptr, &offset, cursor)) return false;
+ if (reg > DWARF_REGISTERS) {
+ ALOGE("DW_CFA_offset_extended: r%d exceeds supported number of registers (%d)", reg, DWARF_REGISTERS);
+ return false;
+ }
+ dstate->regs[reg].rule = 'o';
+ dstate->regs[reg].value = offset * cie_info->data_align;
+ ALOGV("DW_CFA_offset_extended: r%d = o(%d)", reg, dstate->regs[reg].value);
+ break;
+ case DW_CFA_restore_extended: // probably we don't have it on x86.
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ dstate->regs[reg].rule = stack->regs[reg].rule;
+ dstate->regs[reg].value = stack->regs[reg].value;
+ if (reg > DWARF_REGISTERS) {
+ ALOGE("DW_CFA_restore_extended: r%d exceeds supported number of registers (%d)", reg, DWARF_REGISTERS);
+ return false;
+ }
+ ALOGV("DW_CFA_restore: r%d = %c(%d)", reg, dstate->regs[reg].rule, dstate->regs[reg].value);
+ break;
+ case DW_CFA_undefined: // probably we don't have it on x86.
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ dstate->regs[reg].rule = 'u';
+ dstate->regs[reg].value = 0;
+ if (reg > DWARF_REGISTERS) {
+ ALOGE("DW_CFA_undefined: r%d exceeds supported number of registers (%d)", reg, DWARF_REGISTERS);
+ return false;
+ }
+ ALOGV("DW_CFA_undefined: r%d", reg);
+ break;
+ case DW_CFA_same_value: // probably we don't have it on x86.
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ dstate->regs[reg].rule = 's';
+ dstate->regs[reg].value = 0;
+ if (reg > DWARF_REGISTERS) {
+ ALOGE("DW_CFA_undefined: r%d exceeds supported number of registers (%d)", reg, DWARF_REGISTERS);
+ return false;
+ }
+ ALOGV("DW_CFA_same_value: r%d", reg);
+ break;
+ case DW_CFA_register: // probably we don't have it on x86.
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ /* that's new register actually, not offset */
+ if (!try_get_uleb128(memory, ptr, &offset, cursor)) return false;
+ if (reg > DWARF_REGISTERS || offset > DWARF_REGISTERS) {
+ ALOGE("DW_CFA_register: r%d or r%d exceeds supported number of registers (%d)", reg, offset, DWARF_REGISTERS);
+ return false;
+ }
+ dstate->regs[reg].rule = 'r';
+ dstate->regs[reg].value = offset;
+ ALOGV("DW_CFA_register: r%d = r(%d)", reg, dstate->regs[reg].value);
+ break;
+ case DW_CFA_remember_state:
+ if (*stack_ptr == DWARF_STATES_STACK) {
+ ALOGE("DW_CFA_remember_state: states stack overflow %d", *stack_ptr);
+ return false;
+ }
+ stack[(*stack_ptr)++] = *dstate;
+ ALOGV("DW_CFA_remember_state: stacktop moves to %d", *stack_ptr);
+ break;
+ case DW_CFA_restore_state:
+ /* We have CIE state saved at 0 position. It's not supposed to be taken
+ by DW_CFA_restore_state. */
+ if (*stack_ptr == 1) {
+ ALOGE("DW_CFA_restore_state: states stack is empty");
+ return false;
+ }
+ /* Don't touch location on restore. */
+ uintptr_t saveloc = dstate->loc;
+ *dstate = stack[--*stack_ptr];
+ dstate->loc = saveloc;
+ ALOGV("DW_CFA_restore_state: stacktop moves to %d", *stack_ptr);
+ break;
+ case DW_CFA_def_cfa:
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) return false;
+ if (!try_get_uleb128(memory, ptr, &offset, cursor)) return false;
+ dstate->cfa_reg = reg;
+ dstate->cfa_off = offset;
+ ALOGV("DW_CFA_def_cfa: %x(r%d)", offset, reg);
+ break;
+ case DW_CFA_def_cfa_register:
+ if (!try_get_uleb128(memory, ptr, &reg, cursor)) {
+ return false;
+ }
+ dstate->cfa_reg = reg;
+ ALOGV("DW_CFA_def_cfa_register: r%d", reg);
+ break;
+ case DW_CFA_def_cfa_offset:
+ if (!try_get_uleb128(memory, ptr, &offset, cursor)) {
+ return false;
+ }
+ dstate->cfa_off = offset;
+ ALOGV("DW_CFA_def_cfa_offset: %x", offset);
+ break;
+ default:
+ ALOGE("unrecognized DW_CFA_* instruction: 0x%x", inst);
+ return false;
+ }
+ return true;
+}
+
+/* Restoring particular register value based on dwarf state. */
+static bool get_old_register_value(const memory_t* memory, uint32_t cfa,
+ dwarf_state_t* dstate, uint8_t reg,
+ unwind_state_t* state, unwind_state_t* newstate) {
+ uint32_t addr;
+ switch (dstate->regs[reg].rule) {
+ case 0:
+ /* We don't have dstate updated for this register, so assuming value kept the same.
+ Normally we should look into state and return current value as the old one
+ but we don't have all registers in state to handle this properly */
+ ALOGV("get_old_register_value: value of r%d is the same", reg);
+ // for ESP if it's not updated by dwarf rule we assume it's equal to CFA
+ if (reg == DWARF_ESP) {
+ ALOGV("get_old_register_value: adjusting esp to CFA: 0x%x", cfa);
+ newstate->reg[reg] = cfa;
+ } else {
+ newstate->reg[reg] = state->reg[reg];
+ }
+ break;
+ case 'o':
+ addr = cfa + (int32_t)dstate->regs[reg].value;
+ if (!try_get_word(memory, addr, &newstate->reg[reg])) {
+ ALOGE("get_old_register_value: can't read from 0x%x", addr);
+ return false;
+ }
+ ALOGV("get_old_register_value: r%d at 0x%x is 0x%x", reg, addr, newstate->reg[reg]);
+ break;
+ case 'r':
+ /* We don't have all registers in state so don't even try to look at 'r' */
+ ALOGE("get_old_register_value: register lookup not implemented yet");
+ break;
+ default:
+ ALOGE("get_old_register_value: unexpected rule:%c value:%d for register %d",
+ dstate->regs[reg].rule, (int32_t)dstate->regs[reg].value, reg);
+ return false;
+ }
+ return true;
+}
+
+/* Updaing state based on dwarf state. */
+static bool update_state(const memory_t* memory, unwind_state_t* state,
+ dwarf_state_t* dstate, cie_info_t* cie_info) {
+ unwind_state_t newstate;
+ /* We can restore more registers here if we need them. Meanwile doing minimal work here. */
+ /* Getting CFA. */
+ uintptr_t cfa = 0;
+ if (dstate->cfa_reg == DWARF_ESP) {
+ cfa = state->reg[DWARF_ESP] + dstate->cfa_off;
+ } else if (dstate->cfa_reg == DWARF_EBP) {
+ cfa = state->reg[DWARF_EBP] + dstate->cfa_off;
+ } else {
+ ALOGE("update_state: unexpected CFA register: %d", dstate->cfa_reg);
+ return false;
+ }
+ ALOGV("update_state: new CFA: 0x%x", cfa);
+ /* Getting EIP. */
+ if (!get_old_register_value(memory, cfa, dstate, DWARF_EIP, state, &newstate)) return false;
+ /* Getting EBP. */
+ if (!get_old_register_value(memory, cfa, dstate, DWARF_EBP, state, &newstate)) return false;
+ /* Getting ESP. */
+ if (!get_old_register_value(memory, cfa, dstate, DWARF_ESP, state, &newstate)) return false;
+
+ ALOGV("update_state: IP: 0x%x; restore IP: 0x%x", state->reg[DWARF_EIP], newstate.reg[DWARF_EIP]);
+ ALOGV("update_state: EBP: 0x%x; restore EBP: 0x%x", state->reg[DWARF_EBP], newstate.reg[DWARF_EBP]);
+ ALOGV("update_state: ESP: 0x%x; restore ESP: 0x%x", state->reg[DWARF_ESP], newstate.reg[DWARF_ESP]);
+ *state = newstate;
+ return true;
+}
+
+/* Execute CIE and FDE instructions for FDE found with find_fde. */
+static bool execute_fde(const memory_t* memory,
+ const map_info_t* map_info_list,
+ uintptr_t fde,
+ unwind_state_t* state) {
+ uint32_t fde_length = 0;
+ uint32_t cie_length = 0;
+ uintptr_t cie = 0;
+ uintptr_t cie_offset = 0;
+ cie_info_t cie_i;
+ cie_info_t* cie_info = &cie_i;
+ fde_info_t fde_i;
+ fde_info_t* fde_info = &fde_i;
+ dwarf_state_t dwarf_state;
+ dwarf_state_t* dstate = &dwarf_state;
+ dwarf_state_t stack[DWARF_STATES_STACK];
+ uint8_t stack_ptr = 0;
+
+ memset(dstate, 0, sizeof(dwarf_state_t));
+ memset(cie_info, 0, sizeof(cie_info_t));
+ memset(fde_info, 0, sizeof(fde_info_t));
+
+ /* Read common CIE or FDE area:
+ 1st word is length;
+ 2nd word is ID: 0 for CIE, CIE pointer for FDE.
+ */
+ if (!try_get_word(memory, fde, &fde_length)) {
+ return false;
+ }
+ if ((int32_t)fde_length == -1) {
+ ALOGV("execute_fde: 64-bit dwarf detected, not implemented yet");
+ return false;
+ }
+ if (!try_get_word(memory, fde + 4, &cie_offset)) {
+ return false;
+ }
+ if (cie_offset == 0) {
+ /* This is CIE. We shouldn't be here normally. */
+ cie = fde;
+ cie_length = fde_length;
+ } else {
+ /* Find CIE. */
+ /* Positive cie_offset goes backward from current field. */
+ cie = fde + 4 - cie_offset;
+ if (!try_get_word(memory, cie, &cie_length)) {
+ return false;
+ }
+ if ((int32_t)cie_length == -1) {
+ ALOGV("execute_fde: 64-bit dwarf detected, not implemented yet");
+ return false;
+ }
+ if (!try_get_word(memory, cie + 4, &cie_offset)) {
+ return false;
+ }
+ if (cie_offset != 0) {
+ ALOGV("execute_fde: can't find CIE");
+ return false;
+ }
+ }
+ ALOGV("execute_fde: FDE length: %d", fde_length);
+ ALOGV("execute_fde: CIE pointer: %x", cie);
+ ALOGV("execute_fde: CIE length: %d", cie_length);
+
+ /* Read CIE:
+ Augmentation independent:
+ 1st byte is version;
+ next x bytes is /0 terminated augmentation string;
+ next x bytes is unsigned LEB128 encoded code alignment factor;
+ next x bytes is signed LEB128 encoded data alignment factor;
+ next 1 (CIE version 1) or x (CIE version 3 unsigned LEB128) bytes is return register column;
+ Augmentation dependent:
+ if 'z' next x bytes is unsigned LEB128 encoded augmentation data size;
+ if 'L' next 1 byte is LSDA encoding;
+ if 'R' next 1 byte is FDE encoding;
+ if 'S' CIE represents signal handler stack frame;
+ if 'P' next 1 byte is personality encoding folowed by personality function pointer;
+ Next x bytes is CIE program.
+ */
+
+ uint32_t c = 8;
+ if (!try_get_byte(memory, cie, &cie_info->version, &c)) {
+ return false;
+ }
+ ALOGV("execute_fde: CIE version: %d", cie_info->version);
+ uint8_t ch;
+ do {
+ if (!try_get_byte(memory, cie, &ch, &c)) {
+ return false;
+ }
+ switch (ch) {
+ case '\0': break;
+ case 'z': cie_info->aug_z = 1; break;
+ case 'L': cie_info->aug_L = 1; break;
+ case 'R': cie_info->aug_R = 1; break;
+ case 'S': cie_info->aug_S = 1; break;
+ case 'P': cie_info->aug_P = 1; break;
+ default:
+ ALOGV("execute_fde: Unrecognized CIE augmentation char: '%c'", ch);
+ return false;
+ break;
+ }
+ } while (ch);
+ if (!try_get_uleb128(memory, cie, &cie_info->code_align, &c)) {
+ return false;
+ }
+ if (!try_get_sleb128(memory, cie, &cie_info->data_align, &c)) {
+ return false;
+ }
+ if (cie_info->version >= 3) {
+ if (!try_get_uleb128(memory, cie, &cie_info->reg, &c)) {
+ return false;
+ }
+ } else {
+ if (!try_get_byte(memory, cie, (uint8_t*)&cie_info->reg, &c)) {
+ return false;
+ }
+ }
+ ALOGV("execute_fde: CIE code alignment factor: %d", cie_info->code_align);
+ ALOGV("execute_fde: CIE data alignment factor: %d", cie_info->data_align);
+ if (cie_info->aug_z) {
+ if (!try_get_uleb128(memory, cie, &cie_info->aug_z, &c)) {
+ return false;
+ }
+ }
+ if (cie_info->aug_L) {
+ if (!try_get_byte(memory, cie, &cie_info->aug_L, &c)) {
+ return false;
+ }
+ } else {
+ /* Default encoding. */
+ cie_info->aug_L = DW_EH_PE_absptr;
+ }
+ if (cie_info->aug_R) {
+ if (!try_get_byte(memory, cie, &cie_info->aug_R, &c)) {
+ return false;
+ }
+ } else {
+ /* Default encoding. */
+ cie_info->aug_R = DW_EH_PE_absptr;
+ }
+ if (cie_info->aug_P) {
+ /* Get encoding of personality routine pointer. We don't use it now. */
+ if (!try_get_byte(memory, cie, (uint8_t*)&cie_info->aug_P, &c)) {
+ return false;
+ }
+ /* Get routine pointer. */
+ if (!read_dwarf(memory, cie, &cie_info->aug_P, (uint8_t)cie_info->aug_P, &c)) {
+ return false;
+ }
+ }
+ /* CIE program. */
+ /* Length field itself (4 bytes) is not included into length. */
+ stack[0] = *dstate;
+ stack_ptr = 1;
+ while (c < cie_length + 4) {
+ if (!execute_dwarf(memory, cie, cie_info, dstate, &c, stack, &stack_ptr)) {
+ return false;
+ }
+ }
+
+ /* We went directly to CIE. Normally it shouldn't occur. */
+ if (cie == fde) return true;
+
+ /* Go back to FDE. */
+ c = 8;
+ /* Read FDE:
+ Augmentation independent:
+ next x bytes (encoded as specified in CIE) is FDE starting address;
+ next x bytes (encoded as specified in CIE) is FDE number of instructions covered;
+ Augmentation dependent:
+ if 'z' next x bytes is unsigned LEB128 encoded augmentation data size;
+ if 'L' next x bytes is LSDA pointer (encoded as specified in CIE);
+ Next x bytes is FDE program.
+ */
+ if (!read_dwarf(memory, fde, &fde_info->start, (uint8_t)cie_info->aug_R, &c)) {
+ return false;
+ }
+ dstate->loc = fde_info->start;
+ ALOGV("execute_fde: FDE start: %x", dstate->loc);
+ if (!read_dwarf(memory, fde, &fde_info->length, 0, &c)) {
+ return false;
+ }
+ ALOGV("execute_fde: FDE length: %x", fde_info->length);
+ if (cie_info->aug_z) {
+ if (!try_get_uleb128(memory, fde, &fde_info->aug_z, &c)) {
+ return false;
+ }
+ }
+ if (cie_info->aug_L && cie_info->aug_L != DW_EH_PE_omit) {
+ if (!read_dwarf(memory, fde, &fde_info->aug_L, cie_info->aug_L, &c)) {
+ return false;
+ }
+ }
+ /* FDE program. */
+ /* Length field itself (4 bytes) is not included into length. */
+ /* Save CIE state as 0 element of stack. Used by DW_CFA_restore. */
+ stack[0] = *dstate;
+ stack_ptr = 1;
+ while (c < fde_length + 4 && state->reg[DWARF_EIP] >= dstate->loc) {
+ if (!execute_dwarf(memory, fde, cie_info, dstate, &c, stack, &stack_ptr)) {
+ return false;
+ }
+ ALOGV("IP: %x, LOC: %x", state->reg[DWARF_EIP], dstate->loc);
+ }
+
+ return update_state(memory, state, dstate, cie_info);
}
static ssize_t unwind_backtrace_common(const memory_t* memory,
- const map_info_t* map_info_list __attribute__((unused)),
+ const map_info_t* map_info_list,
unwind_state_t* state, backtrace_frame_t* backtrace,
size_t ignore_depth, size_t max_depth) {
+
size_t ignored_frames = 0;
size_t returned_frames = 0;
- for (size_t index = 0; state->ebp && returned_frames < max_depth; index++) {
+ ALOGV("Unwinding tid: %d", memory->tid);
+ ALOGV("IP: %x", state->reg[DWARF_EIP]);
+ ALOGV("BP: %x", state->reg[DWARF_EBP]);
+ ALOGV("SP: %x", state->reg[DWARF_ESP]);
+
+ for (size_t index = 0; returned_frames < max_depth; index++) {
+ uintptr_t fde = find_fde(memory, map_info_list, state->reg[DWARF_EIP]);
+ /* FDE is not found, it may happen if stack is corrupted or calling wrong adress.
+ Getting return address from stack.
+ */
+ if (!fde) {
+ uint32_t ip;
+ ALOGV("trying to restore registers from stack");
+ if (!try_get_word(memory, state->reg[DWARF_EBP] + 4, &ip) ||
+ ip == state->reg[DWARF_EIP]) {
+ ALOGV("can't get IP from stack");
+ break;
+ }
+ /* We've been able to get IP from stack so recording the frame before continue. */
+ backtrace_frame_t* frame = add_backtrace_entry(
+ index ? rewind_pc_arch(memory, state->reg[DWARF_EIP]) : state->reg[DWARF_EIP],
+ backtrace, ignore_depth, max_depth,
+ &ignored_frames, &returned_frames);
+ state->reg[DWARF_EIP] = ip;
+ state->reg[DWARF_ESP] = state->reg[DWARF_EBP] + 8;
+ if (!try_get_word(memory, state->reg[DWARF_EBP], &state->reg[DWARF_EBP])) {
+ ALOGV("can't get EBP from stack");
+ break;
+ }
+ ALOGV("restore IP: %x", state->reg[DWARF_EIP]);
+ ALOGV("restore BP: %x", state->reg[DWARF_EBP]);
+ ALOGV("restore SP: %x", state->reg[DWARF_ESP]);
+ continue;
+ }
backtrace_frame_t* frame = add_backtrace_entry(
- index ? rewind_pc_arch(memory, state->eip) : state->eip,
+ index ? rewind_pc_arch(memory, state->reg[DWARF_EIP]) : state->reg[DWARF_EIP],
backtrace, ignore_depth, max_depth,
&ignored_frames, &returned_frames);
- uint32_t next_esp = state->ebp + 8;
+
+ uint32_t stack_top = state->reg[DWARF_ESP];
+
+ if (!execute_fde(memory, map_info_list, fde, state)) break;
+
if (frame) {
- frame->stack_top = state->esp;
- if (state->esp < next_esp) {
- frame->stack_size = next_esp - state->esp;
+ frame->stack_top = stack_top;
+ if (stack_top < state->reg[DWARF_ESP]) {
+ frame->stack_size = state->reg[DWARF_ESP] - stack_top;
}
}
- state->esp = next_esp;
- if (!try_get_word(memory, state->ebp + 4, &state->eip)
- || !try_get_word(memory, state->ebp, &state->ebp)
- || !state->eip) {
- break;
- }
+ ALOGV("Stack: 0x%x ... 0x%x - %d bytes", frame->stack_top, state->reg[DWARF_ESP], frame->stack_size);
}
-
return returned_frames;
}
@@ -110,9 +819,9 @@ ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo __attribute__((unused)),
const ucontext_t* uc = (const ucontext_t*)sigcontext;
unwind_state_t state;
- state.ebp = uc->uc_mcontext.gregs[REG_EBP];
- state.eip = uc->uc_mcontext.gregs[REG_EIP];
- state.esp = uc->uc_mcontext.gregs[REG_ESP];
+ state.reg[DWARF_EBP] = uc->uc_mcontext.gregs[REG_EBP];
+ state.reg[DWARF_ESP] = uc->uc_mcontext.gregs[REG_ESP];
+ state.reg[DWARF_EIP] = uc->uc_mcontext.gregs[REG_EIP];
memory_t memory;
init_memory(&memory, map_info_list);
@@ -128,9 +837,9 @@ ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
}
unwind_state_t state;
- state.ebp = regs.ebp;
- state.eip = regs.eip;
- state.esp = regs.esp;
+ state.reg[DWARF_EBP] = regs.ebp;
+ state.reg[DWARF_EIP] = regs.eip;
+ state.reg[DWARF_ESP] = regs.esp;
memory_t memory;
init_memory_ptrace(&memory, tid);
diff --git a/libcorkscrew/arch-x86/dwarf.h b/libcorkscrew/arch-x86/dwarf.h
new file mode 100755
index 0000000..962fc55
--- /dev/null
+++ b/libcorkscrew/arch-x86/dwarf.h
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Dwarf2 data encoding flags.
+ */
+
+#define DW_EH_PE_absptr 0x00
+#define DW_EH_PE_omit 0xff
+#define DW_EH_PE_uleb128 0x01
+#define DW_EH_PE_udata2 0x02
+#define DW_EH_PE_udata4 0x03
+#define DW_EH_PE_udata8 0x04
+#define DW_EH_PE_sleb128 0x09
+#define DW_EH_PE_sdata2 0x0A
+#define DW_EH_PE_sdata4 0x0B
+#define DW_EH_PE_sdata8 0x0C
+#define DW_EH_PE_signed 0x08
+#define DW_EH_PE_pcrel 0x10
+#define DW_EH_PE_textrel 0x20
+#define DW_EH_PE_datarel 0x30
+#define DW_EH_PE_funcrel 0x40
+#define DW_EH_PE_aligned 0x50
+#define DW_EH_PE_indirect 0x80
+
+/*
+ * Dwarf2 call frame instructions.
+ */
+
+typedef enum {
+ DW_CFA_advance_loc = 0x40,
+ DW_CFA_offset = 0x80,
+ DW_CFA_restore = 0xc0,
+ DW_CFA_nop = 0x00,
+ DW_CFA_set_loc = 0x01,
+ DW_CFA_advance_loc1 = 0x02,
+ DW_CFA_advance_loc2 = 0x03,
+ DW_CFA_advance_loc4 = 0x04,
+ DW_CFA_offset_extended = 0x05,
+ DW_CFA_restore_extended = 0x06,
+ DW_CFA_undefined = 0x07,
+ DW_CFA_same_value = 0x08,
+ DW_CFA_register = 0x09,
+ DW_CFA_remember_state = 0x0a,
+ DW_CFA_restore_state = 0x0b,
+ DW_CFA_def_cfa = 0x0c,
+ DW_CFA_def_cfa_register = 0x0d,
+ DW_CFA_def_cfa_offset = 0x0e
+} dwarf_CFA;
+
+/*
+ * eh_frame_hdr information.
+*/
+
+typedef struct {
+ uint8_t version;
+ uint8_t eh_frame_ptr_enc;
+ uint8_t fde_count_enc;
+ uint8_t fde_table_enc;
+ uintptr_t eh_frame_ptr;
+ uint32_t fde_count;
+} eh_frame_hdr_info_t;
+
+/*
+ * CIE information.
+*/
+
+typedef struct {
+ uint8_t version;
+ uint32_t code_align;
+ uint32_t data_align;
+ uint32_t reg;
+ uint32_t aug_z;
+ uint8_t aug_L;
+ uint8_t aug_R;
+ uint8_t aug_S;
+ uint32_t aug_P;
+} cie_info_t;
+
+/*
+ * FDE information.
+*/
+
+typedef struct {
+ uint32_t start;
+ uint32_t length; // number of instructions covered by FDE
+ uint32_t aug_z;
+ uint32_t aug_L;
+} fde_info_t;
+
+/*
+ * Dwarf state.
+*/
+
+/* Stack of states: required for DW_CFA_remember_state/DW_CFA_restore_state
+ 30 should be enough */
+#define DWARF_STATES_STACK 30
+
+typedef struct {
+ char rule; // rule: o - offset(value); r - register(value)
+ uint32_t value; // value
+} reg_rule_t;
+
+/* Dwarf preserved number of registers for x86. */
+
+#define DWARF_REGISTERS 17
+
+typedef struct {
+ uintptr_t loc; // location (ip)
+ uint8_t cfa_reg; // index of register where CFA location stored
+ intptr_t cfa_off; // offset
+ reg_rule_t regs[DWARF_REGISTERS]; // dwarf preserved registers for x86
+} dwarf_state_t;
+
+/* DWARF registers we are caring about. */
+
+#define DWARF_EAX 0
+#define DWARF_ECX 1
+#define DWARF_EDX 2
+#define DWARF_EBX 3
+#define DWARF_ESP 4
+#define DWARF_EBP 5
+#define DWARF_ESI 6
+#define DWARF_EDI 7
+#define DWARF_EIP 8
+
+
diff --git a/libcorkscrew/arch-x86/ptrace-x86.c b/libcorkscrew/arch-x86/ptrace-x86.c
index 07cfd3a..9c49b93 100644..100755
--- a/libcorkscrew/arch-x86/ptrace-x86.c
+++ b/libcorkscrew/arch-x86/ptrace-x86.c
@@ -19,11 +19,44 @@
#include "../ptrace-arch.h"
+#include <stddef.h>
+#include <elf.h>
#include <cutils/log.h>
-void load_ptrace_map_info_data_arch(pid_t pid __attribute__((unused)),
- map_info_t* mi __attribute__((unused)),
- map_info_data_t* data __attribute__((unused))) {
+static void load_eh_frame_hdr(pid_t pid, map_info_t* mi, uintptr_t *eh_frame_hdr) {
+ uint32_t elf_phoff;
+ uint32_t elf_phentsize_ehsize;
+ uint32_t elf_shentsize_phnum;
+ if (try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff)
+ && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_ehsize),
+ &elf_phentsize_ehsize)
+ && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum),
+ &elf_shentsize_phnum)) {
+ uint32_t elf_phentsize = elf_phentsize_ehsize >> 16;
+ uint32_t elf_phnum = elf_shentsize_phnum & 0xffff;
+ for (uint32_t i = 0; i < elf_phnum; i++) {
+ uintptr_t elf_phdr = mi->start + elf_phoff + i * elf_phentsize;
+ uint32_t elf_phdr_type;
+ if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_type), &elf_phdr_type)) {
+ break;
+ }
+ if (elf_phdr_type == PT_GNU_EH_FRAME) {
+ uint32_t elf_phdr_offset;
+ if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_offset),
+ &elf_phdr_offset)) {
+ break;
+ }
+ *eh_frame_hdr = mi->start + elf_phdr_offset;
+ ALOGV("Parsed .eh_frame_hdr info for %s: start=0x%08x", mi->name, *eh_frame_hdr);
+ return;
+ }
+ }
+ }
+ *eh_frame_hdr = 0;
+}
+
+void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data) {
+ load_eh_frame_hdr(pid, mi, &data->eh_frame_hdr);
}
void free_ptrace_map_info_data_arch(map_info_t* mi __attribute__((unused)),
diff --git a/libcorkscrew/backtrace.c b/libcorkscrew/backtrace.c
index e57f428..03dbd53 100644
--- a/libcorkscrew/backtrace.c
+++ b/libcorkscrew/backtrace.c
@@ -27,14 +27,37 @@
#include <unistd.h>
#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
#include <pthread.h>
#include <unwind.h>
-#include <sys/exec_elf.h>
#include <cutils/log.h>
#include <cutils/atomic.h>
+#include <elf.h>
-#if HAVE_DLADDR
+#define __USE_GNU // For dladdr(3) in glibc.
#include <dlfcn.h>
+
+#if defined(__BIONIC__)
+
+// Bionic implements and exports gettid but only implements tgkill.
+extern int tgkill(int tgid, int tid, int sig);
+
+#else
+
+// glibc doesn't implement or export either gettid or tgkill.
+
+#include <unistd.h>
+#include <sys/syscall.h>
+
+static pid_t gettid() {
+ return syscall(__NR_gettid);
+}
+
+static int tgkill(int tgid, int tid, int sig) {
+ return syscall(__NR_tgkill, tgid, tid, sig);
+}
+
#endif
typedef struct {
@@ -115,8 +138,6 @@ static void unwind_backtrace_thread_signal_handler(int n __attribute__((unused))
}
#endif
-extern int tgkill(int tgid, int tid, int sig);
-
ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
size_t ignore_depth, size_t max_depth) {
if (tid == gettid()) {
@@ -233,7 +254,6 @@ void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
if (mi->name[0]) {
symbol->map_name = strdup(mi->name);
}
-#if HAVE_DLADDR
Dl_info info;
if (dladdr((const void*)frame->absolute_pc, &info) && info.dli_sname) {
symbol->relative_symbol_addr = (uintptr_t)info.dli_saddr
@@ -241,7 +261,6 @@ void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
symbol->symbol_name = strdup(info.dli_sname);
symbol->demangled_name = demangle_symbol_name(symbol->symbol_name);
}
-#endif
}
}
release_my_map_info_list(milist);
diff --git a/libcorkscrew/map_info.c b/libcorkscrew/map_info.c
index f33378f..6a27664 100644
--- a/libcorkscrew/map_info.c
+++ b/libcorkscrew/map_info.c
@@ -21,6 +21,7 @@
#include <ctype.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <pthread.h>
@@ -56,13 +57,15 @@ static map_info_t* parse_maps_line(const char* line)
mi->start = start;
mi->end = end;
mi->is_readable = strlen(permissions) == 4 && permissions[0] == 'r';
+ mi->is_writable = strlen(permissions) == 4 && permissions[1] == 'w';
mi->is_executable = strlen(permissions) == 4 && permissions[2] == 'x';
mi->data = NULL;
memcpy(mi->name, name, name_len);
mi->name[name_len] = '\0';
ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
- "is_readable=%d, is_executable=%d, name=%s",
- mi->start, mi->end, mi->is_readable, mi->is_executable, mi->name);
+ "is_readable=%d, is_writable=%d, is_executable=%d, name=%s",
+ mi->start, mi->end,
+ mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
}
return mi;
}
@@ -109,6 +112,11 @@ bool is_readable_map(const map_info_t* milist, uintptr_t addr) {
return mi && mi->is_readable;
}
+bool is_writable_map(const map_info_t* milist, uintptr_t addr) {
+ const map_info_t* mi = find_map_info(milist, addr);
+ return mi && mi->is_writable;
+}
+
bool is_executable_map(const map_info_t* milist, uintptr_t addr) {
const map_info_t* mi = find_map_info(milist, addr);
return mi && mi->is_executable;
diff --git a/libcorkscrew/ptrace-arch.h b/libcorkscrew/ptrace-arch.h
index c02df52..4451c29 100644..100755
--- a/libcorkscrew/ptrace-arch.h
+++ b/libcorkscrew/ptrace-arch.h
@@ -33,6 +33,8 @@ typedef struct {
#ifdef __arm__
uintptr_t exidx_start;
size_t exidx_size;
+#elif __i386__
+ uintptr_t eh_frame_hdr;
#endif
symbol_table_t* symbol_table;
} map_info_data_t;
diff --git a/libcorkscrew/ptrace.c b/libcorkscrew/ptrace.c
index cbea8ca..776ef69 100644
--- a/libcorkscrew/ptrace.c
+++ b/libcorkscrew/ptrace.c
@@ -21,6 +21,7 @@
#include <corkscrew/ptrace.h>
#include <errno.h>
+#include <stdlib.h>
#include <sys/ptrace.h>
#include <cutils/log.h>
@@ -128,6 +129,7 @@ void free_ptrace_context(ptrace_context_t* context) {
free_ptrace_map_info_data(mi);
}
free_map_info_list(context->map_info_list);
+ free(context);
}
void find_symbol_ptrace(const ptrace_context_t* context,
diff --git a/libcorkscrew/symbol_table.c b/libcorkscrew/symbol_table.c
index 1b97180..29e4a79 100644
--- a/libcorkscrew/symbol_table.c
+++ b/libcorkscrew/symbol_table.c
@@ -19,14 +19,22 @@
#include <corkscrew/symbol_table.h>
+#include <stdbool.h>
#include <stdlib.h>
+#include <elf.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/mman.h>
-#include <sys/exec_elf.h>
#include <cutils/log.h>
+static bool is_elf(Elf32_Ehdr* e) {
+ return (e->e_ident[EI_MAG0] == ELFMAG0 &&
+ e->e_ident[EI_MAG1] == ELFMAG1 &&
+ e->e_ident[EI_MAG2] == ELFMAG2 &&
+ e->e_ident[EI_MAG3] == ELFMAG3);
+}
+
// Compare function for qsort
static int qcompar(const void *a, const void *b) {
const symbol_t* asym = (const symbol_t*)a;
@@ -67,7 +75,7 @@ symbol_table_t* load_symbol_table(const char *filename) {
// Parse the file header
Elf32_Ehdr *hdr = (Elf32_Ehdr*)base;
- if (!IS_ELF(*hdr)) {
+ if (!is_elf(hdr)) {
goto out_close;
}
Elf32_Shdr *shdr = (Elf32_Shdr*)(base + hdr->e_shoff);
diff --git a/libcorkscrew/test.c b/libcorkscrew/test.c
new file mode 100644
index 0000000..af34c03
--- /dev/null
+++ b/libcorkscrew/test.c
@@ -0,0 +1,64 @@
+#include <corkscrew/backtrace.h>
+#include <corkscrew/symbol_table.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void do_backtrace() {
+ const size_t MAX_DEPTH = 32;
+ backtrace_frame_t* frames = (backtrace_frame_t*) malloc(sizeof(backtrace_frame_t) * MAX_DEPTH);
+ ssize_t frame_count = unwind_backtrace(frames, 0, MAX_DEPTH);
+ fprintf(stderr, "frame_count=%d\n", (int) frame_count);
+
+ backtrace_symbol_t* backtrace_symbols = (backtrace_symbol_t*) malloc(sizeof(backtrace_symbol_t) * frame_count);
+ get_backtrace_symbols(frames, frame_count, backtrace_symbols);
+
+ for (size_t i = 0; i < (size_t) frame_count; ++i) {
+ char line[MAX_BACKTRACE_LINE_LENGTH];
+ format_backtrace_line(i, &frames[i], &backtrace_symbols[i],
+ line, MAX_BACKTRACE_LINE_LENGTH);
+ if (backtrace_symbols[i].symbol_name != NULL) {
+ // get_backtrace_symbols found the symbol's name with dladdr(3).
+ fprintf(stderr, " %s\n", line);
+ } else {
+ // We don't have a symbol. Maybe this is a static symbol, and
+ // we can look it up?
+ symbol_table_t* symbols = NULL;
+ if (backtrace_symbols[i].map_name != NULL) {
+ symbols = load_symbol_table(backtrace_symbols[i].map_name);
+ }
+ const symbol_t* symbol = NULL;
+ if (symbols != NULL) {
+ symbol = find_symbol(symbols, frames[i].absolute_pc);
+ }
+ if (symbol != NULL) {
+ uintptr_t offset = frames[i].absolute_pc - symbol->start;
+ fprintf(stderr, " %s (%s%+d)\n", line, symbol->name, offset);
+ } else {
+ fprintf(stderr, " %s (\?\?\?)\n", line);
+ }
+ free_symbol_table(symbols);
+ }
+ }
+
+ free_backtrace_symbols(backtrace_symbols, frame_count);
+ free(backtrace_symbols);
+ free(frames);
+}
+
+__attribute__ ((noinline)) void g() {
+ fprintf(stderr, "g()\n");
+ do_backtrace();
+}
+
+__attribute__ ((noinline)) int f(int i) {
+ fprintf(stderr, "f(%i)\n", i);
+ if (i == 0) {
+ g();
+ return 0;
+ }
+ return f(i - 1);
+}
+
+int main() {
+ return f(5);
+}
generated by cgit v1.1 at 2025-08-17 05:11:44 +0000