*/
#include <ctype.h>
+#include <elf.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include "debug_mapinfo.h"
#include "malloc_debug_disable.h"
+#if defined(__LP64__)
+#define Elf_W(x) Elf64_##x
+#else
+#define Elf_W(x) Elf32_##x
+#endif
+
// Format of /proc/<PID>/maps:
// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so
static mapinfo_t* parse_maps_line(char* line) {
uintptr_t start;
uintptr_t end;
+ uintptr_t offset;
+ char permissions[4];
int name_pos;
- if (sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %*4s %*x %*x:%*x %*d%n", &start,
- &end, &name_pos) < 2) {
+ if (sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %4s %" PRIxPTR " %*x:%*x %*d%n", &start,
+ &end, permissions, &offset, &name_pos) < 2) {
return NULL;
}
if (mi) {
mi->start = start;
mi->end = end;
+ mi->offset = offset;
+ if (permissions[0] != 'r') {
+ // Any unreadable map will just get a zero load base.
+ mi->load_base = 0;
+ mi->load_base_read = true;
+ } else {
+ mi->load_base_read = false;
+ }
memcpy(mi->name, name, name_len);
mi->name[name_len] = '\0';
}
}
}
+template<typename T>
+static inline bool get_val(mapinfo_t* mi, uintptr_t addr, T* store) {
+ if (addr < mi->start || addr + sizeof(T) > mi->end) {
+ return false;
+ }
+ // Make sure the address is aligned properly.
+ if (addr & (sizeof(T)-1)) {
+ return false;
+ }
+ *store = *reinterpret_cast<T*>(addr);
+ return true;
+}
+
+__LIBC_HIDDEN__ void mapinfo_read_loadbase(mapinfo_t* mi) {
+ mi->load_base = 0;
+ mi->load_base_read = true;
+ uintptr_t addr = mi->start;
+ Elf_W(Ehdr) ehdr;
+ if (!get_val<Elf_W(Half)>(mi, addr + offsetof(Elf_W(Ehdr), e_phnum), &ehdr.e_phnum)) {
+ return;
+ }
+ if (!get_val<Elf_W(Off)>(mi, addr + offsetof(Elf_W(Ehdr), e_phoff), &ehdr.e_phoff)) {
+ return;
+ }
+ addr += ehdr.e_phoff;
+ for (size_t i = 0; i < ehdr.e_phnum; i++) {
+ Elf_W(Phdr) phdr;
+ if (!get_val<Elf_W(Word)>(mi, addr + offsetof(Elf_W(Phdr), p_type), &phdr.p_type)) {
+ return;
+ }
+ if (!get_val<Elf_W(Off)>(mi, addr + offsetof(Elf_W(Phdr), p_offset), &phdr.p_offset)) {
+ return;
+ }
+ if (phdr.p_type == PT_LOAD && phdr.p_offset == mi->offset) {
+ if (!get_val<Elf_W(Addr)>(mi, addr + offsetof(Elf_W(Phdr), p_vaddr), &phdr.p_vaddr)) {
+ return;
+ }
+ mi->load_base = phdr.p_vaddr;
+ return;
+ }
+ addr += sizeof(phdr);
+ }
+}
+
// Find the containing map info for the PC.
__LIBC_HIDDEN__ const mapinfo_t* mapinfo_find(mapinfo_t* mi, uintptr_t pc, uintptr_t* rel_pc) {
for (; mi != NULL; mi = mi->next) {
if ((pc >= mi->start) && (pc < mi->end)) {
- *rel_pc = pc - mi->start;
+ if (!mi->load_base_read) {
+ mapinfo_read_loadbase(mi);
+ }
+ *rel_pc = pc - mi->start + mi->load_base;
return mi;
}
}