From 32c075e1f01849e161724bbd400ba77244e482cc Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 31 Jul 2007 13:33:18 +0000 Subject: . --- nscd/nscd_getpw_r.c | 70 +++++++++++++++++++++++++++++------------------------ 1 file changed, 39 insertions(+), 31 deletions(-) (limited to 'nscd/nscd_getpw_r.c') diff --git a/nscd/nscd_getpw_r.c b/nscd/nscd_getpw_r.c index e8e4d7364f..b84baa1a66 100644 --- a/nscd/nscd_getpw_r.c +++ b/nscd/nscd_getpw_r.c @@ -1,4 +1,5 @@ -/* Copyright (C) 1998, 1999, 2003, 2004, 2005 Free Software Foundation, Inc. +/* Copyright (C) 1998, 1999, 2003, 2004, 2005, 2007 + Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Thorsten Kukuk , 1998. @@ -88,76 +89,81 @@ nscd_getpw_r (const char *key, size_t keylen, request_type type, struct passwd **result) { int gc_cycle; + int nretries = 0; + /* If the mapping is available, try to search there instead of communicating with the nscd. */ struct mapped_database *mapped; mapped = __nscd_get_map_ref (GETFDPW, "passwd", &map_handle, &gc_cycle); retry:; - const pw_response_header *pw_resp = NULL; const char *pw_name = NULL; int retval = -1; const char *recend = (const char *) ~UINTMAX_C (0); + pw_response_header pw_resp; if (mapped != NO_MAPPING) { - const struct datahead *found = __nscd_cache_search (type, key, keylen, - mapped); + struct datahead *found = __nscd_cache_search (type, key, keylen, mapped); if (found != NULL) { - pw_resp = &found->data[0].pwdata; - pw_name = (const char *) (pw_resp + 1); + pw_name = (const char *) (&found->data[0].pwdata + 1); + pw_resp = found->data[0].pwdata; recend = (const char *) found->data + found->recsize; + /* Now check if we can trust pw_resp fields. If GC is + in progress, it can contain anything. */ + if (mapped->head->gc_cycle != gc_cycle) + { + retval = -2; + goto out; + } } } - pw_response_header pw_resp_mem; int sock = -1; - if (pw_resp == NULL) + if (pw_name == NULL) { - sock = __nscd_open_socket (key, keylen, type, &pw_resp_mem, - sizeof (pw_resp_mem)); + sock = __nscd_open_socket (key, keylen, type, &pw_resp, + sizeof (pw_resp)); if (sock == -1) { __nss_not_use_nscd_passwd = 1; goto out; } - - pw_resp = &pw_resp_mem; } /* No value found so far. */ *result = NULL; - if (__builtin_expect (pw_resp->found == -1, 0)) + if (__builtin_expect (pw_resp.found == -1, 0)) { /* The daemon does not cache this database. */ __nss_not_use_nscd_passwd = 1; goto out_close; } - if (pw_resp->found == 1) + if (pw_resp.found == 1) { /* Set the information we already have. */ - resultbuf->pw_uid = pw_resp->pw_uid; - resultbuf->pw_gid = pw_resp->pw_gid; + resultbuf->pw_uid = pw_resp.pw_uid; + resultbuf->pw_gid = pw_resp.pw_gid; char *p = buffer; /* get pw_name */ resultbuf->pw_name = p; - p += pw_resp->pw_name_len; + p += pw_resp.pw_name_len; /* get pw_passwd */ resultbuf->pw_passwd = p; - p += pw_resp->pw_passwd_len; + p += pw_resp.pw_passwd_len; /* get pw_gecos */ resultbuf->pw_gecos = p; - p += pw_resp->pw_gecos_len; + p += pw_resp.pw_gecos_len; /* get pw_dir */ resultbuf->pw_dir = p; - p += pw_resp->pw_dir_len; + p += pw_resp.pw_dir_len; /* get pw_pshell */ resultbuf->pw_shell = p; - p += pw_resp->pw_shell_len; + p += pw_resp.pw_shell_len; ssize_t total = p - buffer; if (__builtin_expect (pw_name + total > recend, 0)) @@ -189,14 +195,14 @@ nscd_getpw_r (const char *key, size_t keylen, request_type type, memcpy (resultbuf->pw_name, pw_name, total); /* Try to detect corrupt databases. */ - if (resultbuf->pw_name[pw_resp->pw_name_len - 1] != '\0' - || resultbuf->pw_passwd[pw_resp->pw_passwd_len - 1] != '\0' - || resultbuf->pw_gecos[pw_resp->pw_gecos_len - 1] != '\0' - || resultbuf->pw_dir[pw_resp->pw_dir_len - 1] != '\0' - || resultbuf->pw_shell[pw_resp->pw_shell_len - 1] != '\0') + if (resultbuf->pw_name[pw_resp.pw_name_len - 1] != '\0' + || resultbuf->pw_passwd[pw_resp.pw_passwd_len - 1] != '\0' + || resultbuf->pw_gecos[pw_resp.pw_gecos_len - 1] != '\0' + || resultbuf->pw_dir[pw_resp.pw_dir_len - 1] != '\0' + || resultbuf->pw_shell[pw_resp.pw_shell_len - 1] != '\0') { /* We cannot use the database. */ - retval = -1; + retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1; goto out_close; } @@ -215,19 +221,21 @@ nscd_getpw_r (const char *key, size_t keylen, request_type type, if (sock != -1) close_not_cancel_no_status (sock); out: - if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1) + if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) { /* When we come here this means there has been a GC cycle while we were looking for the data. This means the data might have been inconsistent. Retry if possible. */ - if ((gc_cycle & 1) != 0) + if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) { /* nscd is just running gc now. Disable using the mapping. */ - __nscd_unmap (mapped); + if (atomic_decrement_val (&mapped->counter) == 0) + __nscd_unmap (mapped); mapped = NO_MAPPING; } - goto retry; + if (retval != -1) + goto retry; } return retval; -- cgit 1.4.1