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dwarf: Utilize ELFs find_section to find the eh_frame.

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Makes it thread-safe.
This commit is contained in:
Bert Wesarg 2017-02-01 22:16:53 +01:00 committed by Dave Watson
parent 1b960e54e9
commit b15e74a884
1 changed files with 13 additions and 53 deletions
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66
src/dwarf/Gfind_proc_info-lsb.c
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@ -525,19 +525,14 @@ dwarf_find_debug_frame (int found, unw_dyn_info_t *di_debug, unw_word_t ip,
#ifndef UNW_REMOTE_ONLY #ifndef UNW_REMOTE_ONLY
#define EH_FRAME_LEN /* strlen(".eh_frame") + 1 */ 10
static Elf_W (Addr) static Elf_W (Addr)
dwarf_find_eh_frame_section(struct dl_phdr_info *info) dwarf_find_eh_frame_section(struct dl_phdr_info *info)
{ {
int fd; int rc;
Elf_W (Ehdr) ehdr; struct elf_image ei;
Elf_W (Half) shstrndx;
Elf_W (Addr) eh_frame = 0; Elf_W (Addr) eh_frame = 0;
unsigned int i; Elf_W (Shdr)* shdr;
const char *file = info->dlpi_name; const char *file = info->dlpi_name;
char secname[EH_FRAME_LEN];
static Elf_W (Shdr) sec_hdrs[100];
char exepath[PATH_MAX]; char exepath[PATH_MAX];
if (strlen(file) == 0) if (strlen(file) == 0)
@ -549,57 +544,22 @@ dwarf_find_eh_frame_section(struct dl_phdr_info *info)
Debug (1, "looking for .eh_frame section in %s\n", Debug (1, "looking for .eh_frame section in %s\n",
file); file);
fd = open(file, O_RDONLY); rc = elf_map_image (&ei, file);
if (rc != 0)
if (fd == -1)
return 0; return 0;
if (read (fd, &ehdr, sizeof (Elf_W (Ehdr))) != sizeof (Elf_W (Ehdr))) shdr = elf_w (find_section) (&ei, ".eh_frame");
goto file_error; if (!shdr)
goto out;
if (ehdr.e_shnum > sizeof(sec_hdrs) / sizeof(Elf_W (Shdr))) eh_frame = shdr->sh_addr + info->dlpi_addr;
{ Debug (4, "found .eh_frame at address %lx\n",
Debug (4, "too many sections (%d > %d)\n", (int) ehdr.e_shnum, (int) (sizeof(sec_hdrs) / sizeof(Elf_W (Shdr)))); eh_frame);
goto file_error;
}
shstrndx = ehdr.e_shstrndx; out:
munmap (ei.image, ei.size);
Debug (4, "opened file '%s'. Section header at offset %d\n",
file, (int) ehdr.e_shoff);
if (lseek (fd, ehdr.e_shoff, SEEK_SET) == (off_t) -1)
goto file_error;
if (read (fd, sec_hdrs, sizeof (Elf_W (Shdr)) * ehdr.e_shnum) != (ssize_t) sizeof (Elf_W (Shdr)) * ehdr.e_shnum)
goto file_error;
for (i = 1; i < ehdr.e_shnum; i++)
{
if (sec_hdrs[shstrndx].sh_size - sec_hdrs[i].sh_name < EH_FRAME_LEN)
goto file_error;
if (lseek (fd, sec_hdrs[shstrndx].sh_offset + sec_hdrs[i].sh_name, SEEK_SET) == (off_t) -1)
goto file_error;
if (read (fd, secname, EH_FRAME_LEN) < (ssize_t) sizeof(EH_FRAME_LEN))
goto file_error;
if (strncmp (secname, ".eh_frame", EH_FRAME_LEN) == 0)
{
eh_frame = sec_hdrs[i].sh_addr + info->dlpi_addr;
Debug (4, "found .eh_frame at address %lx\n",
eh_frame);
break;
}
}
close (fd);
return eh_frame; return eh_frame;
/* An error reading image file. Release resources and return error code */
file_error:
close(fd);
return 0;
} }
/* ptr is a pointer to a dwarf_callback_data structure and, on entry, /* ptr is a pointer to a dwarf_callback_data structure and, on entry,