| /* Initgroups handling in nss_files module. |
| Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <alloca.h> |
| #include <errno.h> |
| #include <grp.h> |
| #include <nss.h> |
| #include <stdio_ext.h> |
| #include <string.h> |
| #include <sys/param.h> |
| #include <stdbool.h> |
| #include <stdlib.h> |
| |
| enum nss_status |
| _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start, |
| long int *size, gid_t **groupsp, long int limit, |
| int *errnop) |
| { |
| FILE *stream = fopen ("/etc/group", "rce"); |
| if (stream == NULL) |
| { |
| *errnop = errno; |
| return *errnop == ENOMEM ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL; |
| } |
| |
| /* No other thread using this stream. */ |
| __fsetlocking (stream, FSETLOCKING_BYCALLER); |
| |
| char *line = NULL; |
| size_t linelen = 0; |
| enum nss_status status = NSS_STATUS_SUCCESS; |
| bool any = false; |
| |
| size_t buflen = 1024; |
| void *buffer = alloca (buflen); |
| bool buffer_use_malloc = false; |
| |
| gid_t *groups = *groupsp; |
| |
| /* We have to iterate over the entire file. */ |
| while (1) |
| { |
| fpos_t pos; |
| fgetpos (stream, &pos); |
| ssize_t n = getline (&line, &linelen, stream); |
| if (n < 0) |
| { |
| if (! feof_unlocked (stream)) |
| status = ((*errnop = errno) == ENOMEM |
| ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL); |
| break; |
| } |
| |
| struct group grp; |
| int res = _nss_files_parse_grent (line, &grp, buffer, buflen, errnop); |
| if (res == -1) |
| { |
| size_t newbuflen = 2 * buflen; |
| if (buffer_use_malloc || ! __libc_use_alloca (buflen + newbuflen)) |
| { |
| void *newbuf = realloc (buffer_use_malloc ? buffer : NULL, |
| newbuflen); |
| if (newbuf == NULL) |
| { |
| *errnop = ENOMEM; |
| status = NSS_STATUS_TRYAGAIN; |
| goto out; |
| } |
| buffer = newbuf; |
| buflen = newbuflen; |
| buffer_use_malloc = true; |
| } |
| else |
| buffer = extend_alloca (buffer, buflen, newbuflen); |
| /* Reread current line, the parser has clobbered it. */ |
| fsetpos (stream, &pos); |
| continue; |
| } |
| |
| if (res > 0 && grp.gr_gid != group) |
| for (char **m = grp.gr_mem; *m != NULL; ++m) |
| if (strcmp (*m, user) == 0) |
| { |
| /* Matches user. Insert this group. */ |
| if (*start == *size) |
| { |
| /* Need a bigger buffer. */ |
| if (limit > 0 && *size == limit) |
| /* We reached the maximum. */ |
| goto out; |
| |
| long int newsize; |
| if (limit <= 0) |
| newsize = 2 * *size; |
| else |
| newsize = MIN (limit, 2 * *size); |
| |
| gid_t *newgroups = realloc (groups, |
| newsize * sizeof (*groups)); |
| if (newgroups == NULL) |
| { |
| *errnop = ENOMEM; |
| status = NSS_STATUS_TRYAGAIN; |
| goto out; |
| } |
| *groupsp = groups = newgroups; |
| *size = newsize; |
| } |
| |
| groups[*start] = grp.gr_gid; |
| *start += 1; |
| any = true; |
| |
| break; |
| } |
| } |
| |
| out: |
| /* Free memory. */ |
| if (buffer_use_malloc) |
| free (buffer); |
| free (line); |
| |
| fclose (stream); |
| |
| return status == NSS_STATUS_SUCCESS && !any ? NSS_STATUS_NOTFOUND : status; |
| } |