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(dl_main): First check existence of ld.so.preload with access.

This commit is contained in:
Ulrich Drepper 2004-09-02 02:52:26 +00:00
parent 6698501fda
commit 761490a1d7
1 changed files with 98 additions and 87 deletions
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21
elf/rtld.c
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@ -1138,8 +1138,16 @@ of this helper program; chances are you did not intend to run this program.\n\
HP_TIMING_ACCUM_NT (load_time, diff); HP_TIMING_ACCUM_NT (load_time, diff);
} }
/* There usually is no ld.so.preload file, it should only be used
for emergencies and testing. So the open call etc should usually
fail. Using access() on a non-existing file is faster than using
open(). So we do this first. If it succeeds we do almost twice
the work but this does not matter, since it is not for production
use. */
static const char preload_file[] = "/etc/ld.so.preload";
if (__builtin_expect (__access (preload_file, R_OK) == 0, 0))
{
/* Read the contents of the file. */ /* Read the contents of the file. */
const char preload_file[] = "/etc/ld.so.preload";
file = _dl_sysdep_read_whole_file (preload_file, &file_size, file = _dl_sysdep_read_whole_file (preload_file, &file_size,
PROT_READ | PROT_WRITE); PROT_READ | PROT_WRITE);
if (__builtin_expect (file != MAP_FAILED, 0)) if (__builtin_expect (file != MAP_FAILED, 0))
@ -1173,7 +1181,8 @@ of this helper program; chances are you did not intend to run this program.\n\
&& file[file_size - 1] != '\n' && file[file_size - 1] != ':') && file[file_size - 1] != '\n' && file[file_size - 1] != ':')
{ {
problem = &file[file_size]; problem = &file[file_size];
while (problem > file && problem[-1] != ' ' && problem[-1] != '\t' while (problem > file && problem[-1] != ' '
&& problem[-1] != '\t'
&& problem[-1] != '\n' && problem[-1] != ':') && problem[-1] != '\n' && problem[-1] != ':')
--problem; --problem;
@ -1204,14 +1213,15 @@ of this helper program; chances are you did not intend to run this program.\n\
args.is_preloaded = 1; args.is_preloaded = 1;
args.mode = 0; args.mode = 0;
(void) _dl_catch_error (&objname, &err_str, map_doit, &args); (void) _dl_catch_error (&objname, &err_str, map_doit,
&args);
if (__builtin_expect (err_str != NULL, 0)) if (__builtin_expect (err_str != NULL, 0))
{ {
_dl_error_printf ("\ _dl_error_printf ("\
ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n", ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n",
p, preload_file); p, preload_file);
/* No need to call free, this is still before the libc's /* No need to call free, this is still before
malloc is used. */ the libc's malloc is used. */
} }
else if (++args.map->l_opencount == 1) else if (++args.map->l_opencount == 1)
/* It is no duplicate. */ /* It is no duplicate. */
@ -1236,6 +1246,7 @@ ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n",
/* We don't need the file anymore. */ /* We don't need the file anymore. */
__munmap (file, file_size); __munmap (file, file_size);
} }
}
if (__builtin_expect (npreloads, 0) != 0) if (__builtin_expect (npreloads, 0) != 0)
{ {