/* Initialize and populate the uids and gids vectors. */ error_t get_credentials (void) { /* Fetch uids... */ uids_len = geteuids (0, 0); if (uids_len < 0) return errno; uids = malloc (uids_len * sizeof (uid_t)); if (! uids) return ENOMEM; uids_len = geteuids (uids_len, uids); if (uids_len < 0) return errno; /* ... and gids. */ gids_len = getgroups (0, 0); if (gids_len < 0) return errno; gids = malloc (gids_len * sizeof (gid_t)); if (! uids) return ENOMEM; gids_len = getgroups (gids_len, gids); if (gids_len < 0) return errno; return 0; }
/*Traces the translator stack on the given underlying node until it finds the first translator called `name` and returns the port pointing to the translator sitting under this one.*/ error_t trace_find (mach_port_t underlying, const char *name, int flags, mach_port_t * port) { error_t err = 0; /*Identity information about the current process */ uid_t *uids; size_t nuids; gid_t *gids; size_t ngids; /*The name and arguments of the translator being passed now */ char *argz = NULL; size_t argz_len = 0; /*The current working directory */ char *cwd = NULL; /*The port to the directory containing the file pointed to by `underlying` */ file_t dir; /*The unauthenticated version of `dir` */ file_t unauth_dir; /*The control port of the current translator */ fsys_t fsys; /*The port to the translator we are currently looking at */ mach_port_t node = underlying; /*The port to the previous translator */ mach_port_t prev_node = MACH_PORT_NULL; /*The retry name and retry type returned by fsys_getroot */ string_t retry_name; retry_type retry; /*Finalizes the execution of this function */ void finalize (void) { /*If there is a working directory, free it */ if (cwd) free (cwd); /*If the ports to the directory exist */ if (dir) PORT_DEALLOC (dir); } /*finalize */ /*Obtain the current working directory */ cwd = getcwd (NULL, 0); if (!cwd) { LOG_MSG ("trace_find: Could not obtain cwd."); return EINVAL; } LOG_MSG ("trace_find: cwd: '%s'", cwd); /*Open a port to this directory */ dir = file_name_lookup (cwd, 0, 0); if (!dir) { finalize (); return ENOENT; } /*Try to get the number of effective UIDs */ nuids = geteuids (0, 0); if (nuids < 0) { finalize (); return EINVAL; } /*Allocate some memory for the UIDs on the stack */ uids = alloca (nuids * sizeof (uid_t)); /*Fetch the UIDs themselves */ nuids = geteuids (nuids, uids); if (nuids < 0) { finalize (); return EINVAL; } /*Try to get the number of effective GIDs */ ngids = getgroups (0, 0); if (ngids < 0) { finalize (); return EINVAL; } /*Allocate some memory for the GIDs on the stack */ gids = alloca (ngids * sizeof (gid_t)); /*Fetch the GIDs themselves */ ngids = getgroups (ngids, gids); if (ngids < 0) { finalize (); return EINVAL; } /*Obtain the unauthenticated version of `dir` */ err = io_restrict_auth (dir, &unauth_dir, 0, 0, 0, 0); if (err) { finalize (); return err; } char buf[256]; char *_buf = buf; size_t len = 256; io_read (node, &_buf, &len, 0, len); LOG_MSG ("trace_find: Read from underlying: '%s'", buf); /*Go up the translator stack */ for (; !err;) { /*retreive the name and options of the current translator */ err = file_get_fs_options (node, &argz, &argz_len); if (err) break; LOG_MSG ("trace_find: Obtained translator '%s'", argz); if (strcmp (argz, name) == 0) { LOG_MSG ("trace_find: Match. Stopping here."); break; } /*try to fetch the control port for this translator */ err = file_get_translator_cntl (node, &fsys); LOG_MSG ("trace_find: err = %d", (int) err); if (err) break; LOG_MSG ("trace_find: Translator control port: %lu", (unsigned long) fsys); prev_node = node; /*fetch the root of the translator */ err = fsys_getroot (fsys, unauth_dir, MACH_MSG_TYPE_COPY_SEND, uids, nuids, gids, ngids, flags | O_NOTRANS, &retry, retry_name, &node); LOG_MSG ("trace_find: fsys_getroot returned %d", (int) err); LOG_MSG ("trace_find: Translator root: %lu", (unsigned long) node); /*TODO: Remove this debug output. */ /*char buf[256]; char * _buf = buf; size_t len = 256; io_read(node, &_buf, &len, 0, len); LOG_MSG("trace_find: Read: '%s'", buf); */ } /*If the error occurred (most probably) because of the fact that we have reached the top of the translator stack */ if ((err == EMACH_SEND_INVALID_DEST) || (err == ENXIO)) /*this is OK */ err = 0; /*Return the port to read from */ *port = prev_node; /*Return the result of operations */ finalize (); return err; } /*trace_find */