usr/src/lib/libast/common/comp/eaccess.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * access() euid/egid implementation
  25  */
  26
  27 #include <ast.h>
  28 #include <errno.h>
  29 #include <ls.h>
  30
  31 #include "FEATURE/eaccess"
  32
  33 #if _lib_eaccess
  34
  35 NoN(eaccess)
  36
  37 #else
  38
  39 #if defined(__EXPORT__)
  40 #define extern  __EXPORT__
  41 #endif
  42
  43 extern int
  44 eaccess(const char* path, register int flags)
  45 {
  46 #ifdef EFF_ONLY_OK
  47         return access(path, flags|EFF_ONLY_OK);
  48 #else
  49 #if _lib_euidaccess
  50         return euidaccess(path, flags);
  51 #else
  52         register int    mode;
  53         struct stat     st;
  54
  55         static int      init;
  56         static uid_t    ruid;
  57         static uid_t    euid;
  58         static gid_t    rgid;
  59         static gid_t    egid;
  60
  61         if (!init)
  62         {
  63                 ruid = getuid();
  64                 euid = geteuid();
  65                 rgid = getgid();
  66                 egid = getegid();
  67                 init = (ruid == euid && rgid == egid) ? 1 : -1;
  68         }
  69         if (init > 0 || flags == F_OK)
  70                 return access(path, flags);
  71         if (stat(path, &st))
  72                 return -1;
  73         mode = 0;
  74         if (euid == 0)
  75         {
  76                 if (!S_ISREG(st.st_mode) || !(flags & X_OK) || (st.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)))
  77                         return 0;
  78                 goto nope;
  79         }
  80         else if (euid == st.st_uid)
  81         {
  82                 if (flags & R_OK)
  83                         mode |= S_IRUSR;
  84                 if (flags & W_OK)
  85                         mode |= S_IWUSR;
  86                 if (flags & X_OK)
  87                         mode |= S_IXUSR;
  88         }
  89         else if (egid == st.st_gid)
  90         {
  91 #if _lib_getgroups
  92         setgroup:
  93 #endif
  94                 if (flags & R_OK)
  95                         mode |= S_IRGRP;
  96                 if (flags & W_OK)
  97                         mode |= S_IWGRP;
  98                 if (flags & X_OK)
  99                         mode |= S_IXGRP;
 100         }
 101         else
 102         {
 103 #if _lib_getgroups
 104                 register int    n;
 105
 106                 static int      ngroups = -2;
 107                 static gid_t*   groups;
 108
 109                 if (ngroups == -2)
 110                 {
 111                         if ((ngroups = getgroups(0, (gid_t*)0)) <= 0)
 112                                 ngroups = NGROUPS_MAX;
 113                         if (!(groups = newof(0, gid_t, ngroups + 1, 0)))
 114                                 ngroups = -1;
 115                         else
 116                                 ngroups = getgroups(ngroups, groups);
 117                 }
 118                 n = ngroups;
 119                 while (--n >= 0)
 120                         if (groups[n] == st.st_gid)
 121                                 goto setgroup;
 122 #endif
 123                 if (flags & R_OK)
 124                         mode |= S_IROTH;
 125                 if (flags & W_OK)
 126                         mode |= S_IWOTH;
 127                 if (flags & X_OK)
 128                         mode |= S_IXOTH;
 129         }
 130         if ((st.st_mode & mode) == mode)
 131                 return 0;
 132  nope:
 133         errno = EACCES;
 134         return -1;
 135 #endif
 136 #endif
 137 }
 138
 139 #endif