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Diffstat (limited to 'sysdeps/posix/euidaccess.c')
| -rw-r--r-- | sysdeps/posix/euidaccess.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/sysdeps/posix/euidaccess.c b/sysdeps/posix/euidaccess.c new file mode 100644 index 0000000..feaa9a2 --- /dev/null +++ b/sysdeps/posix/euidaccess.c @@ -0,0 +1,201 @@ +/* euidaccess -- check if effective user id can access file + Copyright (C) 1990, 1991, 1995 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* Written by David MacKenzie and Torbjorn Granlund. + Adapted for GNU C library by Roland McGrath. */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <sys/types.h> +#include <sys/stat.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 */ + +#if defined (HAVE_UNISTD_H) || defined (_LIBC) +#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 errno +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 + + +#ifdef _LIBC + +#define group_member __group_member + +#else + +/* 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; + +/* Nonzero if UID, GID, EUID, and EGID have valid values. */ +static int have_ids = 0; + +#ifdef HAVE_GETGROUPS +int group_member (); +#else +#define group_member(gid) 0 +#endif + +#endif + + +/* 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) + const char *path; + int mode; +{ + struct stat stats; + int granted; + +#ifdef _LIBC + uid_t uid = getuid (), euid = geteuid (); + gid_t gid = getgid (), egid = getegid (); +#else + if (have_ids == 0) + { + have_ids = 1; + uid = getuid (); + gid = getgid (); + euid = geteuid (); + egid = getegid (); + } +#endif + + if (uid == euid && gid == egid) + /* If we are not set-uid or set-gid, access does the same. */ + return access (path, mode); + + if (stat (path, &stats)) + return -1; + + mode &= (X_OK | W_OK | R_OK); /* Clear any bogus bits. */ +#if R_OK != S_IROTH || W_OK != S_IWOTH || X_OK != S_IXOTH + ?error Oops, portability assumptions incorrect. +#endif + + if (mode == F_OK) + return 0; /* The file exists. */ + + /* The super-user can read and write any file, and execute any file + that anyone can execute. */ + if (euid == 0 && ((mode & X_OK) == 0 + || (stats.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)))) + return 0; + + if (euid == stats.st_uid) + granted = (unsigned) (stats.st_mode & (mode << 6)) >> 6; + else if (egid == stats.st_gid || group_member (stats.st_gid)) + granted = (unsigned) (stats.st_mode & (mode << 3)) >> 3; + else + granted = (stats.st_mode & mode); + if (granted == mode) + return 0; + errno = EACCESS; + return -1; +} + +#ifdef TEST +#include <stdio.h> +#include <errno.h> +#include "error.h" + +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 |