libcsupport/src/getgroups.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  *  @file
0005  *
0006  *  @brief Get Supplementary IDs
0007  *
0008  *  @ingroup libcsupport
0009  */
0010
0011 /*
0012  * COPYRIGHT (C) 1989-1999 On-Line Applications Research Corporation (OAR).
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #ifdef HAVE_CONFIG_H
0037 #include "config.h"
0038 #endif
0039
0040 #include <sys/types.h>
0041 #include <grp.h>
0042 #include <pwd.h>
0043 #include <string.h>
0044 #include <unistd.h>
0045
0046 #include <rtems/seterr.h>
0047
0048 /**
0049  *  4.2.3 Get Supplementary IDs, P1003.1b-1993, p. 86
0050  */
0051 int getgroups(
0052   int    gidsetsize,
0053   gid_t  grouplist[]
0054 )
0055 {
0056   int rv;
0057   struct passwd pwd;
0058   struct passwd *pwd_res;
0059   char buf[256];
0060   gid_t gid;
0061   const char *user;
0062   struct group *grp;
0063
0064   rv = getpwuid_r(getuid(), &pwd, &buf[0], sizeof(buf), &pwd_res);
0065   if (rv != 0) {
0066     return rv;
0067   }
0068
0069   gid = pwd.pw_gid;
0070   user = pwd.pw_name;
0071
0072   setgrent();
0073
0074   while ((grp = getgrent()) != NULL) {
0075     char **mem = &grp->gr_mem[0];
0076
0077     if (grp->gr_gid == gid) {
0078       continue;
0079     }
0080
0081     while (*mem != NULL) {
0082       if (strcmp(*mem, user) == 0) {
0083         if (rv < gidsetsize) {
0084           grouplist[rv] = grp->gr_gid;
0085         }
0086
0087         ++rv;
0088
0089         break;
0090       }
0091
0092       ++mem;
0093     }
0094   }
0095
0096   endgrent();
0097
0098   if (gidsetsize == 0 || rv <= gidsetsize) {
0099     return rv;
0100   } else {
0101     rtems_set_errno_and_return_minus_one(EINVAL);
0102   }
0103 }