diff options
Diffstat (limited to 'elf/rtld.c')
| -rw-r--r-- | elf/rtld.c | 141 |
1 files changed, 104 insertions, 37 deletions
diff --git a/elf/rtld.c b/elf/rtld.c index 95830c54c2..2707da60df 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -53,6 +53,15 @@ static void print_unresolved (int errcode, const char *objname, static void print_missing_version (int errcode, const char *objname, const char *errsting); + +/* This is a list of all the modes the dynamic loader can be in. */ +enum mode { normal, list, verify, trace }; + +/* Process all environments variables the dynamic linker must recognize. + Since all of them start with `LD_' we are a bit smarter while finding + all the entries. */ +static void process_envvars (enum mode *modep, int *lazyp); + int _dl_argc; char **_dl_argv; const char *_dl_rpath; @@ -147,7 +156,6 @@ _dl_start (void *arg) return _dl_sysdep_start (arg, &dl_main); } - /* Now life is peachy; we can do all normal operations. On to the real work. */ @@ -260,7 +268,7 @@ dl_main (const ElfW(Phdr) *phdr, const ElfW(Phdr) *ph; struct link_map *main_map; int lazy; - enum { normal, list, verify, trace } mode; + enum mode mode; struct link_map **preloads; unsigned int npreloads; const char *preloadlist; @@ -268,41 +276,8 @@ dl_main (const ElfW(Phdr) *phdr, char *file; int has_interp = 0; - /* Test whether we want to see the content of the auxiliary array passed - up from the kernel. */ - if (getenv ("LD_SHOW_AUXV") != NULL) - _dl_show_auxv (); - - mode = getenv ("LD_TRACE_LOADED_OBJECTS") != NULL ? trace : normal; - _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; - - /* LAZY is determined by the environment variable LD_WARN and - LD_BIND_NOW if we trace the binary. */ - if (mode == trace) - lazy = (_dl_verbose - ? (*(getenv ("LD_BIND_NOW") ?: "") == '\0' ? 1 : 0) : -1); - else - lazy = !__libc_enable_secure && *(getenv ("LD_BIND_NOW") ?: "") == '\0'; - - /* See whether we want to use profiling. */ - _dl_profile = getenv ("LD_PROFILE"); - if (_dl_profile != NULL) - if (_dl_profile[0] == '\0') - /* An empty string is of not much help. Disable profiling. */ - _dl_profile = NULL; - else - { - /* OK, we have the name of a shared object we want to - profile. It's up to the user to provide a good name, it - must match the file name or soname of one of the loaded - objects. Now let's see where we are supposed to place the - result. */ - _dl_profile_output = getenv ("LD_PROFILE_OUTPUT"); - - if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0') - /* This is the default place. */ - _dl_profile_output = "/var/tmp"; - } + /* Process the environment variable which control the behaviour. */ + process_envvars (&mode, &lazy); /* Set up a flag which tells we are just starting. */ _dl_starting_up = 1; @@ -930,3 +905,95 @@ print_missing_version (int errcode __attribute__ ((unused)), _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", ": ", objname, ": ", errstring, "\n", NULL); } + +/* Process all environments variables the dynamic linker must recognize. + Since all of them start with `LD_' we are a bit smarter while finding + all the entries. */ +static void +process_envvars (enum mode *modep, int *lazyp) +{ + char **runp = NULL; + char *envline; + enum mode mode = normal; + int bind_now = 0; + + /* This is the default place for profiling data file. */ + _dl_profile_output = "/var/tmp"; + + while ((envline = _dl_next_ld_env_entry (&runp)) != NULL) + { + int result; + + /* Do we bind early? */ + result = strncmp (&envline[3], "BIND_NOW=", 9); + if (result == 0) + { + bind_now = 1; + continue; + } + if (result < 0) + continue; + + /* Which shared object shall be profiled. */ + result = strncmp (&envline[3], "PROFILE=", 8); + if (result == 0) + { + _dl_profile = &envline[11]; + if (*_dl_profile == '\0') + _dl_profile = NULL; + continue; + } + if (result < 0) + continue; + + /* Where to place the profiling data file. */ + result = strncmp (&envline[3], "PROFILE_OUTPUT=", 15); + if (result == 0) + { + _dl_profile_output = &envline[18]; + if (*_dl_profile_output == '\0') + _dl_profile_output = "/var/tmp"; + continue; + } + if (result < 0) + continue; + + /* Test whether we want to see the content of the auxiliary + array passed up from the kernel. */ + result = strncmp (&envline[3], "SHOW_AUXV=", 10); + if (result == 0) + { + _dl_show_auxv (); + continue; + } + if (result < 0) + continue; + + /* The mode of the dynamic linker can be set. */ + result = strncmp (&envline[3], "TRACE_LOADED_OBJECTS=", 21); + if (result == 0) + { + mode = trace; + continue; + } + if (result < 0) + continue; + + /* Warning level, verbose or not. */ + result = strncmp (&envline[3], "WARN=", 5); + if (result == 0) + { + _dl_verbose = envline[8] != '\0'; + continue; + } + } + + /* LAZY is determined by the environment variable LD_WARN and + LD_BIND_NOW if we trace the binary. */ + if (mode == trace) + *lazyp = _dl_verbose ? !bind_now : -1; + else + *lazyp = !__libc_enable_secure && !bind_now; + + *modep = mode; +} |