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(dl_main): First check existence of ld.so.preload with access.
This commit is contained in:
Ulrich Drepper
parent
6698501fda
commit
761490a1d7
185
elf/rtld.c
185
elf/rtld.c
@ -1138,103 +1138,114 @@ of this helper program; chances are you did not intend to run this program.\n\
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HP_TIMING_ACCUM_NT (load_time, diff);
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}
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/* Read the contents of the file. */
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const char preload_file[] = "/etc/ld.so.preload";
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file = _dl_sysdep_read_whole_file (preload_file, &file_size,
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PROT_READ | PROT_WRITE);
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if (__builtin_expect (file != MAP_FAILED, 0))
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/* There usually is no ld.so.preload file, it should only be used
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for emergencies and testing. So the open call etc should usually
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fail. Using access() on a non-existing file is faster than using
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open(). So we do this first. If it succeeds we do almost twice
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the work but this does not matter, since it is not for production
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use. */
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static const char preload_file[] = "/etc/ld.so.preload";
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if (__builtin_expect (__access (preload_file, R_OK) == 0, 0))
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{
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/* Parse the file. It contains names of libraries to be loaded,
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separated by white spaces or `:'. It may also contain
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comments introduced by `#'. */
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char *problem;
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char *runp;
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size_t rest;
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/* Eliminate comments. */
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runp = file;
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rest = file_size;
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while (rest > 0)
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/* Read the contents of the file. */
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file = _dl_sysdep_read_whole_file (preload_file, &file_size,
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PROT_READ | PROT_WRITE);
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if (__builtin_expect (file != MAP_FAILED, 0))
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{
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char *comment = memchr (runp, '#', rest);
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if (comment == NULL)
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break;
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/* Parse the file. It contains names of libraries to be loaded,
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separated by white spaces or `:'. It may also contain
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comments introduced by `#'. */
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char *problem;
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char *runp;
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size_t rest;
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rest -= comment - runp;
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do
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*comment = ' ';
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while (--rest > 0 && *++comment != '\n');
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}
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/* We have one problematic case: if we have a name at the end of
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the file without a trailing terminating characters, we cannot
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place the \0. Handle the case separately. */
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if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
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&& file[file_size - 1] != '\n' && file[file_size - 1] != ':')
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{
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problem = &file[file_size];
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while (problem > file && problem[-1] != ' ' && problem[-1] != '\t'
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&& problem[-1] != '\n' && problem[-1] != ':')
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--problem;
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if (problem > file)
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problem[-1] = '\0';
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}
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else
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{
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problem = NULL;
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file[file_size - 1] = '\0';
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}
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HP_TIMING_NOW (start);
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if (file != problem)
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{
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char *p;
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/* Eliminate comments. */
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runp = file;
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while ((p = strsep (&runp, ": \t\n")) != NULL)
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if (p[0] != '\0')
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{
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const char *objname;
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const char *err_str = NULL;
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struct map_args args;
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rest = file_size;
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while (rest > 0)
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{
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char *comment = memchr (runp, '#', rest);
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if (comment == NULL)
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break;
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args.str = p;
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args.loader = GL(dl_loaded);
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args.is_preloaded = 1;
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args.mode = 0;
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rest -= comment - runp;
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do
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*comment = ' ';
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while (--rest > 0 && *++comment != '\n');
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}
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(void) _dl_catch_error (&objname, &err_str, map_doit, &args);
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if (__builtin_expect (err_str != NULL, 0))
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/* We have one problematic case: if we have a name at the end of
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the file without a trailing terminating characters, we cannot
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place the \0. Handle the case separately. */
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if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
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&& file[file_size - 1] != '\n' && file[file_size - 1] != ':')
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{
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problem = &file[file_size];
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while (problem > file && problem[-1] != ' '
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&& problem[-1] != '\t'
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&& problem[-1] != '\n' && problem[-1] != ':')
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--problem;
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if (problem > file)
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problem[-1] = '\0';
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}
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else
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{
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problem = NULL;
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file[file_size - 1] = '\0';
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}
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HP_TIMING_NOW (start);
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if (file != problem)
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{
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char *p;
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runp = file;
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while ((p = strsep (&runp, ": \t\n")) != NULL)
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if (p[0] != '\0')
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{
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_dl_error_printf ("\
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const char *objname;
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const char *err_str = NULL;
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struct map_args args;
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args.str = p;
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args.loader = GL(dl_loaded);
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args.is_preloaded = 1;
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args.mode = 0;
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(void) _dl_catch_error (&objname, &err_str, map_doit,
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&args);
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if (__builtin_expect (err_str != NULL, 0))
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{
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_dl_error_printf ("\
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ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n",
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p, preload_file);
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/* No need to call free, this is still before the libc's
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malloc is used. */
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p, preload_file);
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/* No need to call free, this is still before
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the libc's malloc is used. */
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}
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else if (++args.map->l_opencount == 1)
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/* It is no duplicate. */
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++npreloads;
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}
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else if (++args.map->l_opencount == 1)
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/* It is no duplicate. */
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++npreloads;
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}
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}
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if (problem != NULL)
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{
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char *p = strndupa (problem, file_size - (problem - file));
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struct link_map *new_map = _dl_map_object (GL(dl_loaded), p, 1,
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lt_library, 0, 0);
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if (++new_map->l_opencount == 1)
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/* It is no duplicate. */
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++npreloads;
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}
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HP_TIMING_NOW (stop);
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HP_TIMING_DIFF (diff, start, stop);
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HP_TIMING_ACCUM_NT (load_time, diff);
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/* We don't need the file anymore. */
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__munmap (file, file_size);
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}
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if (problem != NULL)
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{
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char *p = strndupa (problem, file_size - (problem - file));
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struct link_map *new_map = _dl_map_object (GL(dl_loaded), p, 1,
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lt_library, 0, 0);
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if (++new_map->l_opencount == 1)
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/* It is no duplicate. */
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++npreloads;
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}
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HP_TIMING_NOW (stop);
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HP_TIMING_DIFF (diff, start, stop);
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HP_TIMING_ACCUM_NT (load_time, diff);
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/* We don't need the file anymore. */
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__munmap (file, file_size);
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}
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if (__builtin_expect (npreloads, 0) != 0)
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