Dwarf backtrace for MIPS

The Dwarf parsing code was copied from backtrace-x86.c
and modified for MIPS

Change-Id: I62c698fbbea28be39320a921dd778269dc478528

1 files changed, 50 insertions, 1 deletions

diff --git a/libcorkscrew/arch-mips/ptrace-mips.c b/libcorkscrew/arch-mips/ptrace-mips.c
index f0ea110..ba3b60a 100644
--- a/libcorkscrew/arch-mips/ptrace-mips.c
+++ b/libcorkscrew/arch-mips/ptrace-mips.c
@@ -19,10 +19,59 @@
 
 #include "../ptrace-arch.h"
 
+#include <stddef.h>
+#include <elf.h>
 #include <cutils/log.h>
 
+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;
+
+
+    try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff);
+    ALOGV("reading 0x%08x elf_phoff:%x",  mi->start + offsetof(Elf32_Ehdr, e_phoff), elf_phoff);
+    try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_ehsize), &elf_phentsize_ehsize);
+    ALOGV("reading 0x%08x elf_phentsize_ehsize:%x", 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);
+    ALOGV("reading 0x%08x elf_shentsize_phnum:%x", mi->start + offsetof(Elf32_Ehdr, e_phnum), 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) {
+    ALOGV("load_ptrace_map_info_data_arch");
+    load_eh_frame_hdr(pid, mi, &data->eh_frame_hdr);
 }
 
-void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data) {
+void free_ptrace_map_info_data_arch(map_info_t* mi __attribute__((unused)),
+                                    map_info_data_t* data __attribute__((unused))) {
+    ALOGV("free_ptrace_map_info_data_arch");
 }