Initial revision

1 files changed, 203 insertions, 0 deletions

diff --git a/lib/euidaccess.c b/lib/euidaccess.c
new file mode 100644
index 000000000..1073c9741
--- /dev/null
+++ b/lib/euidaccess.c
@@ -0,0 +1,203 @@
+/* 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
+   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.
+
+   This program 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 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.  */
+
+/* Written by David MacKenzie and Torbjorn Granlund. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.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 STDC_HEADERS
+extern int errno;
+#endif
+
+#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
+#endif
+
+#include "safe-stat.h"
+
+/* 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;
+
+int group_member ();
+
+/* Nonzero if UID, GID, EUID, and EGID have valid values. */
+static int have_ids = 0;
+
+/* 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.  */
+
+int
+eaccess_stat (statp, mode, path)
+     struct stat *statp;
+     int mode;
+     char *path;
+{
+  int granted;
+
+  mode &= (X_OK | W_OK | R_OK);	/* Clear any bogus bits. */
+
+  if (mode == F_OK)
+    return 0;			/* The file exists. */
+
+  if (have_ids == 0)
+    {
+      have_ids = 1;
+      uid = getuid ();
+      gid = getgid ();
+      euid = geteuid ();
+      egid = getegid ();
+    }
+
+  if (path && uid == euid && gid == egid)
+    {
+      return access (path, mode);
+    }
+
+  /* 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;
+
+  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;
+}
+
+/* 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. */
+
+int
+euidaccess (path, mode)
+     char *path;
+     int mode;
+{
+  struct stat stats;
+
+  if (have_ids == 0)
+    {
+      have_ids = 1;
+      uid = getuid ();
+      gid = getgid ();
+      euid = geteuid ();
+      egid = getegid ();
+    }
+
+  if (uid == euid && gid == egid)
+    {
+      return access (path, mode);
+    }
+
+  if (SAFE_STAT (path, &stats))
+    return -1;
+
+  return eaccess_stat (&stats, mode, path);
+}
+
+#ifdef TEST
+#include <stdio.h>
+#include <errno.h>
+
+void error ();
+
+char *program_name;
+
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  char *file;
+  int mode;
+  int err;
+
+  program_name = argv[0];
+  if (argc < 3)
+    abort ();
+  file = argv[1];
+  mode = atoi (argv[2]);
+
+  err = euidaccess (file, mode);
+  printf ("%d\n", err);
+  if (err != 0)
+    error (0, errno, "%s", file);
+  exit (0);
+}
+#endif