lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 2004-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <assert.h> |
| 20 | #include <errno.h> |
| 21 | #include <grp.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <string.h> |
| 24 | #include <unistd.h> |
| 25 | #include <not-cancel.h> |
| 26 | |
| 27 | #include "nscd-client.h" |
| 28 | #include "nscd_proto.h" |
| 29 | |
| 30 | |
| 31 | /* We use the same mapping as in nscd_getgr. */ |
| 32 | libc_locked_map_ptr (extern, __gr_map_handle) attribute_hidden; |
| 33 | |
| 34 | |
| 35 | int |
| 36 | __nscd_getgrouplist (const char *user, gid_t group, long int *size, |
| 37 | gid_t **groupsp, long int limit) |
| 38 | { |
| 39 | size_t userlen = strlen (user) + 1; |
| 40 | int gc_cycle; |
| 41 | int nretries = 0; |
| 42 | |
| 43 | /* If the mapping is available, try to search there instead of |
| 44 | communicating with the nscd. */ |
| 45 | struct mapped_database *mapped; |
| 46 | mapped = __nscd_get_map_ref (GETFDGR, "group", &__gr_map_handle, &gc_cycle); |
| 47 | |
| 48 | retry:; |
| 49 | char *respdata = NULL; |
| 50 | int retval = -1; |
| 51 | int sock = -1; |
| 52 | initgr_response_header initgr_resp; |
| 53 | |
| 54 | if (mapped != NO_MAPPING) |
| 55 | { |
| 56 | struct datahead *found = __nscd_cache_search (INITGROUPS, user, |
| 57 | userlen, mapped, |
| 58 | sizeof initgr_resp); |
| 59 | if (found != NULL) |
| 60 | { |
| 61 | respdata = (char *) (&found->data[0].initgrdata + 1); |
| 62 | initgr_resp = found->data[0].initgrdata; |
| 63 | char *recend = (char *) found->data + found->recsize; |
| 64 | |
| 65 | /* Now check if we can trust initgr_resp fields. If GC is |
| 66 | in progress, it can contain anything. */ |
| 67 | if (mapped->head->gc_cycle != gc_cycle) |
| 68 | { |
| 69 | retval = -2; |
| 70 | goto out; |
| 71 | } |
| 72 | |
| 73 | if (respdata + initgr_resp.ngrps * sizeof (int32_t) > recend) |
| 74 | goto out; |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | /* If we do not have the cache mapped, try to get the data over the |
| 79 | socket. */ |
| 80 | if (respdata == NULL) |
| 81 | { |
| 82 | sock = __nscd_open_socket (user, userlen, INITGROUPS, &initgr_resp, |
| 83 | sizeof (initgr_resp)); |
| 84 | if (sock == -1) |
| 85 | { |
| 86 | /* nscd not running or wrong version. */ |
| 87 | __nss_not_use_nscd_group = 1; |
| 88 | goto out; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | if (initgr_resp.found == 1) |
| 93 | { |
| 94 | /* The following code assumes that gid_t and int32_t are the |
| 95 | same size. This is the case for al existing implementation. |
| 96 | If this should change some code needs to be added which |
| 97 | doesn't use memcpy but instead copies each array element one |
| 98 | by one. */ |
| 99 | assert (sizeof (int32_t) == sizeof (gid_t)); |
| 100 | assert (initgr_resp.ngrps >= 0); |
| 101 | |
| 102 | /* Make sure we have enough room. We always count GROUP in even |
| 103 | though we might not end up adding it. */ |
| 104 | if (*size < initgr_resp.ngrps + 1) |
| 105 | { |
| 106 | gid_t *newp = realloc (*groupsp, |
| 107 | (initgr_resp.ngrps + 1) * sizeof (gid_t)); |
| 108 | if (newp == NULL) |
| 109 | /* We cannot increase the buffer size. */ |
| 110 | goto out_close; |
| 111 | |
| 112 | *groupsp = newp; |
| 113 | *size = initgr_resp.ngrps + 1; |
| 114 | } |
| 115 | |
| 116 | if (respdata == NULL) |
| 117 | { |
| 118 | /* Read the data from the socket. */ |
| 119 | if ((size_t) __readall (sock, *groupsp, initgr_resp.ngrps |
| 120 | * sizeof (gid_t)) |
| 121 | == initgr_resp.ngrps * sizeof (gid_t)) |
| 122 | retval = initgr_resp.ngrps; |
| 123 | } |
| 124 | else |
| 125 | { |
| 126 | /* Just copy the data. */ |
| 127 | retval = initgr_resp.ngrps; |
| 128 | memcpy (*groupsp, respdata, retval * sizeof (gid_t)); |
| 129 | } |
| 130 | } |
| 131 | else |
| 132 | { |
| 133 | if (__glibc_unlikely (initgr_resp.found == -1)) |
| 134 | { |
| 135 | /* The daemon does not cache this database. */ |
| 136 | __nss_not_use_nscd_group = 1; |
| 137 | goto out_close; |
| 138 | } |
| 139 | |
| 140 | /* No group found yet. */ |
| 141 | retval = 0; |
| 142 | |
| 143 | assert (*size >= 1); |
| 144 | } |
| 145 | |
| 146 | /* Check whether GROUP is part of the mix. If not, add it. */ |
| 147 | if (retval >= 0) |
| 148 | { |
| 149 | int cnt; |
| 150 | for (cnt = 0; cnt < retval; ++cnt) |
| 151 | if ((*groupsp)[cnt] == group) |
| 152 | break; |
| 153 | |
| 154 | if (cnt == retval) |
| 155 | (*groupsp)[retval++] = group; |
| 156 | } |
| 157 | |
| 158 | out_close: |
| 159 | if (sock != -1) |
| 160 | close_not_cancel_no_status (sock); |
| 161 | out: |
| 162 | if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) |
| 163 | { |
| 164 | /* When we come here this means there has been a GC cycle while we |
| 165 | were looking for the data. This means the data might have been |
| 166 | inconsistent. Retry if possible. */ |
| 167 | if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) |
| 168 | { |
| 169 | /* nscd is just running gc now. Disable using the mapping. */ |
| 170 | if (atomic_decrement_val (&mapped->counter) == 0) |
| 171 | __nscd_unmap (mapped); |
| 172 | mapped = NO_MAPPING; |
| 173 | } |
| 174 | |
| 175 | if (retval != -1) |
| 176 | goto retry; |
| 177 | } |
| 178 | |
| 179 | return retval; |
| 180 | } |