/* euidaccess -- check if effective user id can access file
- Copyright (C) 1990, 1991 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ Copyright (C) 1990-1991, 1995, 1998, 2000, 2003-2006, 2008-2014 Free
+ Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-/* Written by David MacKenzie and Torbjorn Granlund. */
+/* Written by David MacKenzie and Torbjorn Granlund.
+ Adapted for GNU C library by Roland McGrath. */
-#ifdef HAVE_CONFIG_H
-#include <config.h>
+#ifndef _LIBC
+# include <config.h>
#endif
+#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <unistd.h>
-#ifdef S_IEXEC
-#ifndef S_IXUSR
-#define S_IXUSR S_IEXEC
-#endif
-#ifndef S_IXGRP
-#define S_IXGRP (S_IEXEC >> 3)
-#endif
-#ifndef S_IXOTH
-#define S_IXOTH (S_IEXEC >> 6)
-#endif
-#endif /* S_IEXEC */
+#include "root-uid.h"
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
+#if HAVE_LIBGEN_H
+# include <libgen.h>
#endif
-#ifdef _POSIX_VERSION
-#include <limits.h>
-#if !defined(NGROUPS_MAX) || NGROUPS_MAX < 1
-#undef NGROUPS_MAX
-#define NGROUPS_MAX sysconf (_SC_NGROUPS_MAX)
-#endif /* NGROUPS_MAX */
-
-#else /* not _POSIX_VERSION */
-uid_t getuid ();
-gid_t getgid ();
-uid_t geteuid ();
-gid_t getegid ();
-#include <sys/param.h>
-#if !defined(NGROUPS_MAX) && defined(NGROUPS)
-#define NGROUPS_MAX NGROUPS
-#endif /* not NGROUPS_MAX and NGROUPS */
-#endif /* not POSIX_VERSION */
-
#include <errno.h>
-#ifndef errno
-extern int errno;
+#ifndef __set_errno
+# define __set_errno(val) errno = (val)
#endif
-#if defined(EACCES) && !defined(EACCESS)
-#define EACCESS EACCES
+#if defined EACCES && !defined EACCESS
+# define EACCESS EACCES
#endif
#ifndef F_OK
-#define F_OK 0
-#define X_OK 1
-#define W_OK 2
-#define R_OK 4
+# define F_OK 0
+# define X_OK 1
+# define W_OK 2
+# define R_OK 4
#endif
-/* The user's real user id. */
-static uid_t uid;
-
-/* The user's real group id. */
-static gid_t gid;
-
-/* The user's effective user id. */
-static uid_t euid;
-/* The user's effective group id. */
-static gid_t egid;
+#ifdef _LIBC
-int group_member ();
+# define access __access
+# define getuid __getuid
+# define getgid __getgid
+# define geteuid __geteuid
+# define getegid __getegid
+# define group_member __group_member
+# define euidaccess __euidaccess
+# undef stat
+# define stat stat64
-/* Nonzero if UID, GID, EUID, and EGID have valid values. */
-static int have_ids = 0;
+#endif
-/* Like euidaccess, except that a pointer to a filled-in stat structure
- describing the file is provided instead of a filename.
- Because this function is almost guaranteed to fail on systems that
- use ACLs, a third argument *PATH may be used. If it is non-NULL,
- it is assumed to be the name of the file corresponding to STATP.
- Then, if the user is not running set-uid or set-gid, use access
- instead of attempting a manual and non-portable comparison. */
+/* Return 0 if the user has permission of type MODE on FILE;
+ otherwise, return -1 and set 'errno'.
+ Like access, except that it uses the effective user and group
+ id's instead of the real ones, and it does not always check for read-only
+ file system, text busy, etc. */
-static int
-eaccess_stat (statp, mode, path)
- const struct stat *statp;
- int mode;
- const char *path;
+int
+euidaccess (const char *file, int mode)
{
- int granted;
+#if HAVE_FACCESSAT /* glibc, AIX 7, Solaris 11, Cygwin 1.7 */
+ return faccessat (AT_FDCWD, file, mode, AT_EACCESS);
+#elif defined EFF_ONLY_OK /* IRIX, OSF/1, Interix */
+ return access (file, mode | EFF_ONLY_OK);
+#elif defined ACC_SELF /* AIX */
+ return accessx (file, mode, ACC_SELF);
+#elif HAVE_EACCESS /* FreeBSD */
+ return eaccess (file, mode);
+#else /* Mac OS X, NetBSD, OpenBSD, HP-UX, Solaris, Cygwin, mingw, BeOS */
+
+ uid_t uid = getuid ();
+ gid_t gid = getgid ();
+ uid_t euid = geteuid ();
+ gid_t egid = getegid ();
+ struct stat stats;
- mode &= (X_OK | W_OK | R_OK); /* Clear any bogus bits. */
+# if HAVE_DECL_SETREGID && PREFER_NONREENTRANT_EUIDACCESS
- if (mode == F_OK)
- return 0; /* The file exists. */
+ /* Define PREFER_NONREENTRANT_EUIDACCESS if you prefer euidaccess to
+ return the correct result even if this would make it
+ nonreentrant. Define this only if your entire application is
+ safe even if the uid or gid might temporarily change. If your
+ application uses signal handlers or threads it is probably not
+ safe. */
- if (have_ids == 0)
+ if (mode == F_OK)
+ return stat (file, &stats);
+ else
{
- have_ids = 1;
- uid = getuid ();
- gid = getgid ();
- euid = geteuid ();
- egid = getegid ();
- }
+ int result;
+ int saved_errno;
- if (path && uid == euid && gid == egid)
- {
- return access (path, mode);
- }
+ if (uid != euid)
+ setreuid (euid, uid);
+ if (gid != egid)
+ setregid (egid, gid);
- /* The super-user can read and write any file, and execute any file
- that anyone can execute. */
- if (euid == 0 && ((mode & X_OK) == 0
- || (statp->st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))))
- return 0;
+ result = access (file, mode);
+ saved_errno = errno;
- if (euid == statp->st_uid)
- granted = (unsigned) (statp->st_mode & (mode << 6)) >> 6;
- else if (egid == statp->st_gid
-#ifdef HAVE_GETGROUPS
- || group_member (statp->st_gid)
-#endif
- )
- granted = (unsigned) (statp->st_mode & (mode << 3)) >> 3;
- else
- granted = (statp->st_mode & mode);
- if (granted == mode)
- return 0;
- errno = EACCESS;
- return -1;
-}
+ /* Restore them. */
+ if (uid != euid)
+ setreuid (uid, euid);
+ if (gid != egid)
+ setregid (gid, egid);
-/* Return 0 if the user has permission of type MODE on file PATH;
- otherwise, return -1 and set `errno' to EACCESS.
- Like access, except that it uses the effective user and group
- id's instead of the real ones, and it does not check for read-only
- filesystem, text busy, etc. */
+ errno = saved_errno;
+ return result;
+ }
-int
-euidaccess (path, mode)
- const char *path;
- int mode;
-{
- struct stat stats;
+# else
- if (have_ids == 0)
- {
- have_ids = 1;
- uid = getuid ();
- gid = getgid ();
- euid = geteuid ();
- egid = getegid ();
- }
+ /* The following code assumes the traditional Unix model, and is not
+ correct on systems that have ACLs or the like. However, it's
+ better than nothing, and it is reentrant. */
+ unsigned int granted;
if (uid == euid && gid == egid)
- {
- return access (path, mode);
- }
+ /* If we are not set-uid or set-gid, access does the same. */
+ return access (file, mode);
- if (stat (path, &stats))
+ if (stat (file, &stats) != 0)
return -1;
- return eaccess_stat (&stats, mode, path);
-}
+ /* The super-user can read and write any file, and execute any file
+ that anyone can execute. */
+ if (euid == ROOT_UID
+ && ((mode & X_OK) == 0
+ || (stats.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))))
+ return 0;
-#ifdef TEST
-#include <stdio.h>
-#include <errno.h>
+ /* Convert the mode to traditional form, clearing any bogus bits. */
+ if (R_OK == 4 && W_OK == 2 && X_OK == 1 && F_OK == 0)
+ mode &= 7;
+ else
+ mode = ((mode & R_OK ? 4 : 0)
+ + (mode & W_OK ? 2 : 0)
+ + (mode & X_OK ? 1 : 0));
+
+ if (mode == 0)
+ return 0; /* The file exists. */
+
+ /* Convert the file's permission bits to traditional form. */
+ if (S_IRUSR == (4 << 6) && S_IWUSR == (2 << 6) && S_IXUSR == (1 << 6)
+ && S_IRGRP == (4 << 3) && S_IWGRP == (2 << 3) && S_IXGRP == (1 << 3)
+ && S_IROTH == (4 << 0) && S_IWOTH == (2 << 0) && S_IXOTH == (1 << 0))
+ granted = stats.st_mode;
+ else
+ granted = ((stats.st_mode & S_IRUSR ? 4 << 6 : 0)
+ + (stats.st_mode & S_IWUSR ? 2 << 6 : 0)
+ + (stats.st_mode & S_IXUSR ? 1 << 6 : 0)
+ + (stats.st_mode & S_IRGRP ? 4 << 3 : 0)
+ + (stats.st_mode & S_IWGRP ? 2 << 3 : 0)
+ + (stats.st_mode & S_IXGRP ? 1 << 3 : 0)
+ + (stats.st_mode & S_IROTH ? 4 << 0 : 0)
+ + (stats.st_mode & S_IWOTH ? 2 << 0 : 0)
+ + (stats.st_mode & S_IXOTH ? 1 << 0 : 0));
+
+ if (euid == stats.st_uid)
+ granted >>= 6;
+ else if (egid == stats.st_gid || group_member (stats.st_gid))
+ granted >>= 3;
+
+ if ((mode & ~granted) == 0)
+ return 0;
+ __set_errno (EACCESS);
+ return -1;
-void error ();
+# endif
+#endif
+}
+#undef euidaccess
+#ifdef weak_alias
+weak_alias (__euidaccess, euidaccess)
+#endif
+\f
+#ifdef TEST
+# include <error.h>
+# include <stdio.h>
+# include <stdlib.h>
char *program_name;
int
-main (argc, argv)
- int argc;
- char **argv;
+main (int argc, char **argv)
{
char *file;
int mode;
projects / gnulib.git / blobdiff