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Diffstat (limited to 'lib/sh/eaccess.c')
| -rw-r--r-- | lib/sh/eaccess.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/lib/sh/eaccess.c b/lib/sh/eaccess.c new file mode 100644 index 0000000..989bc22 --- /dev/null +++ b/lib/sh/eaccess.c @@ -0,0 +1,222 @@ +/* eaccess.c - eaccess replacement for the shell, plus other access functions. */ + +/* Copyright (C) 2006 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash 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 3 of the License, or + (at your option) any later version. + + Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#if defined (HAVE_CONFIG_H) +# include <config.h> +#endif + +#include <stdio.h> + +#include "bashtypes.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include "bashansi.h" + +#include <errno.h> +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +#if !defined (_POSIX_VERSION) && defined (HAVE_SYS_FILE_H) +# include <sys/file.h> +#endif /* !_POSIX_VERSION */ +#include "posixstat.h" +#include "filecntl.h" + +#include "shell.h" + +#if !defined (R_OK) +#define R_OK 4 +#define W_OK 2 +#define X_OK 1 +#define F_OK 0 +#endif /* R_OK */ + +static int path_is_devfd __P((const char *)); +static int sh_stataccess __P((char *, int)); +#if HAVE_DECL_SETREGID +static int sh_euidaccess __P((char *, int)); +#endif + +static int +path_is_devfd (path) + const char *path; +{ + if (path[0] == '/' && path[1] == 'd' && strncmp (path, "/dev/fd/", 8) == 0) + return 1; + else if (STREQN (path, "/dev/std", 8)) + { + if (STREQ (path+8, "in") || STREQ (path+8, "out") || STREQ (path+8, "err")) + return 1; + else + return 0; + } + else + return 0; +} + +/* A wrapper for stat () which disallows pathnames that are empty strings + and handles /dev/fd emulation on systems that don't have it. */ +int +sh_stat (path, finfo) + const char *path; + struct stat *finfo; +{ + if (*path == '\0') + { + errno = ENOENT; + return (-1); + } + if (path[0] == '/' && path[1] == 'd' && strncmp (path, "/dev/fd/", 8) == 0) + { +#if !defined (HAVE_DEV_FD) + intmax_t fd; + int r; + + if (legal_number (path + 8, &fd) && fd == (int)fd) + { + r = fstat ((int)fd, finfo); + if (r == 0 || errno != EBADF) + return (r); + } + errno = ENOENT; + return (-1); +#else + /* If HAVE_DEV_FD is defined, DEV_FD_PREFIX is defined also, and has a + trailing slash. Make sure /dev/fd/xx really uses DEV_FD_PREFIX/xx. + On most systems, with the notable exception of linux, this is + effectively a no-op. */ + char pbuf[32]; + strcpy (pbuf, DEV_FD_PREFIX); + strcat (pbuf, path + 8); + return (stat (pbuf, finfo)); +#endif /* !HAVE_DEV_FD */ + } +#if !defined (HAVE_DEV_STDIN) + else if (STREQN (path, "/dev/std", 8)) + { + if (STREQ (path+8, "in")) + return (fstat (0, finfo)); + else if (STREQ (path+8, "out")) + return (fstat (1, finfo)); + else if (STREQ (path+8, "err")) + return (fstat (2, finfo)); + else + return (stat (path, finfo)); + } +#endif /* !HAVE_DEV_STDIN */ + return (stat (path, finfo)); +} + +/* Do the same thing access(2) does, but use the effective uid and gid, + and don't make the mistake of telling root that any file is + executable. This version uses stat(2). */ +static int +sh_stataccess (path, mode) + char *path; + int mode; +{ + struct stat st; + + if (sh_stat (path, &st) < 0) + return (-1); + + if (current_user.euid == 0) + { + /* Root can read or write any file. */ + if ((mode & X_OK) == 0) + return (0); + + /* Root can execute any file that has any one of the execute + bits set. */ + if (st.st_mode & S_IXUGO) + return (0); + } + + if (st.st_uid == current_user.euid) /* owner */ + mode <<= 6; + else if (group_member (st.st_gid)) + mode <<= 3; + + if (st.st_mode & mode) + return (0); + + errno = EACCES; + return (-1); +} + +#if HAVE_DECL_SETREGID +/* Version to call when uid != euid or gid != egid. We temporarily swap + the effective and real uid and gid as appropriate. */ +static int +sh_euidaccess (path, mode) + char *path; + int mode; +{ + int r, e; + + if (current_user.uid != current_user.euid) + setreuid (current_user.euid, current_user.uid); + if (current_user.gid != current_user.egid) + setregid (current_user.egid, current_user.gid); + + r = access (path, mode); + e = errno; + + if (current_user.uid != current_user.euid) + setreuid (current_user.uid, current_user.euid); + if (current_user.gid != current_user.egid) + setregid (current_user.gid, current_user.egid); + + errno = e; + return r; +} +#endif + +int +sh_eaccess (path, mode) + char *path; + int mode; +{ + if (path_is_devfd (path)) + return (sh_stataccess (path, mode)); + +#if defined (HAVE_EACCESS) /* FreeBSD */ + return (eaccess (path, mode)); +#elif defined (EFF_ONLY_OK) /* SVR4(?), SVR4.2 */ + return access (path, mode|EFF_ONLY_OK); +#else + if (mode == F_OK) + return (sh_stataccess (path, mode)); + +# if HAVE_DECL_SETREGID + if (current_user.uid != current_user.euid || current_user.gid != current_user.egid) + return (sh_euidaccess (path, mode)); +# endif + + if (current_user.uid == current_user.euid && current_user.gid == current_user.egid) + return (access (path, mode)); + + return (sh_stataccess (path, mode)); +#endif +} |