diff options
| -rw-r--r-- | elf/dl-main.h | 8 | ||||
| -rw-r--r-- | elf/dl-usage.c | 24 | ||||
| -rw-r--r-- | elf/rtld.c | 56 |
3 files changed, 75 insertions, 13 deletions
diff --git a/elf/dl-main.h b/elf/dl-main.h index 79c9c40056..ac7249a580 100644 --- a/elf/dl-main.h +++ b/elf/dl-main.h @@ -63,6 +63,7 @@ struct audit_list enum rtld_mode { rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace, + rtld_mode_help, }; /* Aggregated state information extracted from environment variables @@ -101,6 +102,11 @@ call_init_paths (const struct dl_main_state *state) } /* Print ld.so usage information and exit. */ -_Noreturn void _dl_usage (void) attribute_hidden; +_Noreturn void _dl_usage (const char *argv0, const char *wrong_option) + attribute_hidden; + +/* Print ld.so --help output and exit. */ +_Noreturn void _dl_help (const char *argv0, struct dl_main_state *state) + attribute_hidden; #endif /* _DL_MAIN */ diff --git a/elf/dl-usage.c b/elf/dl-usage.c index f3d89d22b7..c1820dca2f 100644 --- a/elf/dl-usage.c +++ b/elf/dl-usage.c @@ -19,12 +19,24 @@ #include <dl-cache.h> #include <dl-main.h> #include <ldsodefs.h> +#include <unistd.h> void -_dl_usage (void) +_dl_usage (const char *argv0, const char *wrong_option) { - _dl_fatal_printf ("\ -Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ + if (wrong_option != NULL) + _dl_error_printf ("%s: unrecognized option '%s'\n", argv0, wrong_option); + else + _dl_error_printf ("%s: missing program name\n", argv0); + _dl_error_printf ("Try '%s --help' for more information.\n", argv0); + _exit (EXIT_FAILURE); +} + +void +_dl_help (const char *argv0, struct dl_main_state *state) +{ + _dl_printf ("\ +Usage: %s [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ You have invoked `ld.so', the helper program for shared library executables.\n\ This program usually lives in the file `/lib/ld.so', and special directives\n\ in executable files using ELF shared libraries tell the system's program\n\ @@ -47,5 +59,9 @@ of this helper program; chances are you did not intend to run this program.\n\ in LIST\n\ --audit LIST use objects named in LIST as auditors\n\ --preload LIST preload objects named in LIST\n\ - --argv0 STRING set argv[0] to STRING before running\n"); + --argv0 STRING set argv[0] to STRING before running\n\ + --help display this help and exit\n\ +", + argv0); + _exit (EXIT_SUCCESS); } diff --git a/elf/rtld.c b/elf/rtld.c index c0609e4310..2eeec981a5 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1151,6 +1151,7 @@ dl_main (const ElfW(Phdr) *phdr, _dl_starting_up = 1; #endif + const char *ld_so_name = _dl_argv[0]; if (*user_entry == (ElfW(Addr)) ENTRY_POINT) { /* Ho ho. We are not the program interpreter! We are the program @@ -1178,8 +1179,12 @@ dl_main (const ElfW(Phdr) *phdr, while (_dl_argc > 1) if (! strcmp (_dl_argv[1], "--list")) { - state.mode = rtld_mode_list; - GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */ + if (state.mode != rtld_mode_help) + { + state.mode = rtld_mode_list; + /* This means do no dependency analysis. */ + GLRO(dl_lazy) = -1; + } ++_dl_skip_args; --_dl_argc; @@ -1187,7 +1192,8 @@ dl_main (const ElfW(Phdr) *phdr, } else if (! strcmp (_dl_argv[1], "--verify")) { - state.mode = rtld_mode_verify; + if (state.mode != rtld_mode_help) + state.mode = rtld_mode_verify; ++_dl_skip_args; --_dl_argc; @@ -1242,13 +1248,34 @@ dl_main (const ElfW(Phdr) *phdr, _dl_argc -= 2; _dl_argv += 2; } + else if (strcmp (_dl_argv[1], "--help") == 0) + { + state.mode = rtld_mode_help; + --_dl_argc; + ++_dl_argv; + } + else if (_dl_argv[1][0] == '-' && _dl_argv[1][1] == '-') + { + if (_dl_argv[1][1] == '\0') + /* End of option list. */ + break; + else + /* Unrecognized option. */ + _dl_usage (ld_so_name, _dl_argv[1]); + } else break; /* If we have no further argument the program was called incorrectly. Grant the user some education. */ if (_dl_argc < 2) - _dl_usage (); + { + if (state.mode == rtld_mode_help) + /* --help without an executable is not an error. */ + _dl_help (ld_so_name, &state); + else + _dl_usage (ld_so_name, NULL); + } ++_dl_skip_args; --_dl_argc; @@ -1273,7 +1300,8 @@ dl_main (const ElfW(Phdr) *phdr, break; } - if (__glibc_unlikely (state.mode == rtld_mode_verify)) + if (__glibc_unlikely (state.mode == rtld_mode_verify + || state.mode == rtld_mode_help)) { const char *objname; const char *err_str = NULL; @@ -1286,9 +1314,16 @@ dl_main (const ElfW(Phdr) *phdr, (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args); if (__glibc_unlikely (err_str != NULL)) - /* We don't free the returned string, the programs stops - anyway. */ - _exit (EXIT_FAILURE); + { + /* We don't free the returned string, the programs stops + anyway. */ + if (state.mode == rtld_mode_help) + /* Mask the failure to load the main object. The help + message contains less information in this case. */ + _dl_help (ld_so_name, &state); + else + _exit (EXIT_FAILURE); + } } else { @@ -1647,6 +1682,11 @@ dl_main (const ElfW(Phdr) *phdr, audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_AUDIT); audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_DEPAUDIT); + /* At this point, all data has been obtained that is included in the + --help output. */ + if (__glibc_unlikely (state.mode == rtld_mode_help)) + _dl_help (ld_so_name, &state); + /* If we have auditing DSOs to load, do it now. */ bool need_security_init = true; if (state.audit_list.length > 0) |