diff options
Diffstat (limited to 'src/common/compat.c')
-rw-r--r-- | src/common/compat.c | 126 |
1 files changed, 116 insertions, 10 deletions
diff --git a/src/common/compat.c b/src/common/compat.c index 1c460b6ae..e25ecc462 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -1708,6 +1708,106 @@ log_credential_status(void) } #endif +#ifndef _WIN32 +/** Cached struct from the last getpwname() call we did successfully. */ +static struct passwd *passwd_cached = NULL; + +/** Helper: copy a struct passwd object. + * + * We only copy the fields pw_uid, pw_gid, pw_name, pw_dir. Tor doesn't use + * any others, and I don't want to run into incompatibilities. + */ +static struct passwd * +tor_passwd_dup(const struct passwd *pw) +{ + struct passwd *new_pw = tor_malloc_zero(sizeof(struct passwd)); + if (pw->pw_name) + new_pw->pw_name = tor_strdup(pw->pw_name); + if (pw->pw_dir) + new_pw->pw_dir = tor_strdup(pw->pw_dir); + new_pw->pw_uid = pw->pw_uid; + new_pw->pw_gid = pw->pw_gid; + + return new_pw; +} + +/** Helper: free one of our cached 'struct passwd' values. */ +static void +tor_passwd_free(struct passwd *pw) +{ + if (!pw) + return; + + tor_free(pw->pw_name); + tor_free(pw->pw_dir); + tor_free(pw); +} + +/** Wrapper around getpwnam() that caches result. Used so that we don't need + * to give the sandbox access to /etc/passwd. + * + * The following fields alone will definitely be copied in the output: pw_uid, + * pw_gid, pw_name, pw_dir. Other fields are not present in cached values. + * + * When called with a NULL argument, this function clears storage associated + * with static variables it uses. + **/ +const struct passwd * +tor_getpwnam(const char *username) +{ + struct passwd *pw; + + if (username == NULL) { + tor_passwd_free(passwd_cached); + passwd_cached = NULL; + return NULL; + } + + if ((pw = getpwnam(username))) { + tor_passwd_free(passwd_cached); + passwd_cached = tor_passwd_dup(pw); + log_notice(LD_GENERAL, "Caching new entry %s for %s", + passwd_cached->pw_name, username); + return pw; + } + + /* Lookup failed */ + if (! passwd_cached || ! passwd_cached->pw_name) + return NULL; + + if (! strcmp(username, passwd_cached->pw_name)) + return passwd_cached; + + return NULL; +} + +/** Wrapper around getpwnam() that can use cached result from + * tor_getpwnam(). Used so that we don't need to give the sandbox access to + * /etc/passwd. + * + * The following fields alone will definitely be copied in the output: pw_uid, + * pw_gid, pw_name, pw_dir. Other fields are not present in cached values. + */ +const struct passwd * +tor_getpwuid(uid_t uid) +{ + struct passwd *pw; + + if ((pw = getpwuid(uid))) { + return pw; + } + + /* Lookup failed */ + if (! passwd_cached) + return NULL; + + if (uid == passwd_cached->pw_uid) + return passwd_cached; + + return NULL; +} +#endif + /** Call setuid and setgid to run as <b>user</b> and switch to their * primary group. Return 0 on success. On failure, log and return -1. */ @@ -1715,7 +1815,7 @@ int switch_id(const char *user) { #ifndef _WIN32 - struct passwd *pw = NULL; + const struct passwd *pw = NULL; uid_t old_uid; gid_t old_gid; static int have_already_switched_id = 0; @@ -1736,7 +1836,7 @@ switch_id(const char *user) old_gid = getgid(); /* Lookup the user and group information, if we have a problem, bail out. */ - pw = getpwnam(user); + pw = tor_getpwnam(user); if (pw == NULL) { log_warn(LD_CONFIG, "Error setting configured user: %s not found", user); return -1; @@ -1907,10 +2007,10 @@ tor_disable_debugger_attach(void) char * get_user_homedir(const char *username) { - struct passwd *pw; + const struct passwd *pw; tor_assert(username); - if (!(pw = getpwnam(username))) { + if (!(pw = tor_getpwnam(username))) { log_err(LD_CONFIG,"User \"%s\" not found.", username); return NULL; } @@ -2435,6 +2535,12 @@ tor_pthread_helper_fn(void *_data) func(arg); return NULL; } +/** + * A pthread attribute to make threads start detached. + */ +static pthread_attr_t attr_detached; +/** True iff we've called tor_threads_init() */ +static int threads_initialized = 0; #endif /** Minimalist interface to run a void function in the background. On @@ -2458,12 +2564,12 @@ spawn_func(void (*func)(void *), void *data) #elif defined(USE_PTHREADS) pthread_t thread; tor_pthread_data_t *d; + if (PREDICT_UNLIKELY(!threads_initialized)) + tor_threads_init(); d = tor_malloc(sizeof(tor_pthread_data_t)); d->data = data; d->func = func; - if (pthread_create(&thread,NULL,tor_pthread_helper_fn,d)) - return -1; - if (pthread_detach(thread)) + if (pthread_create(&thread,&attr_detached,tor_pthread_helper_fn,d)) return -1; return 0; #else @@ -2820,8 +2926,6 @@ tor_get_thread_id(void) * "reentrant" mutexes (i.e., once we can re-lock if we're already holding * them.) */ static pthread_mutexattr_t attr_reentrant; -/** True iff we've called tor_threads_init() */ -static int threads_initialized = 0; /** Initialize <b>mutex</b> so it can be locked. Every mutex must be set * up with tor_mutex_init() or tor_mutex_new(); not both. */ void @@ -2965,6 +3069,8 @@ tor_threads_init(void) if (!threads_initialized) { pthread_mutexattr_init(&attr_reentrant); pthread_mutexattr_settype(&attr_reentrant, PTHREAD_MUTEX_RECURSIVE); + tor_assert(0==pthread_attr_init(&attr_detached)); + tor_assert(0==pthread_attr_setdetachstate(&attr_detached, 1)); threads_initialized = 1; set_main_thread(); } @@ -3453,7 +3559,7 @@ get_total_system_memory(size_t *mem_out) *mem_out = mem_cached = (size_t) m; - return -1; + return 0; } #ifdef TOR_UNIT_TESTS |