This file is cd.def, from which is created cd.c. It implements the
builtins "cd" and "pwd" in Bash.
Copyright (C) 1987-2016 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/>.
$PRODUCES cd.c
#include <config.h>
#if defined (HAVE_UNISTD_H)
# ifdef _MINIX
# include <sys/types.h>
# endif
# include <unistd.h>
#endif
#include "../bashtypes.h"
#include "posixdir.h"
#include "posixstat.h"
#if defined (HAVE_SYS_PARAM_H)
#include <sys/param.h>
#endif
#include <fcntl.h>
#include <stdio.h>
#include "../bashansi.h"
#include "../bashintl.h"
#include <errno.h>
#include <tilde/tilde.h>
#include "../shell.h"
#include "../flags.h"
#include "maxpath.h"
#include "common.h"
#include "bashgetopt.h"
#if !defined (errno)
extern int errno;
#endif /* !errno */
extern int posixly_correct;
extern int array_needs_making;
extern const char * const bash_getcwd_errstr;
static int bindpwd __P((int));
static int setpwd __P((char *));
static char *resetpwd __P((char *));
static int change_to_directory __P((char *, int, int));
static int cdxattr __P((char *, char **));
static void resetxattr __P((void));
/* Change this to 1 to get cd spelling correction by default. */
int cdspelling = 0;
int cdable_vars;
static int eflag; /* file scope so bindpwd() can see it */
static int xattrflag; /* O_XATTR support for openat */
static int xattrfd = -1;
$BUILTIN cd
$FUNCTION cd_builtin
$SHORT_DOC cd [-L|[-P [-e]] [-@]] [dir]
Change the shell working directory.
Change the current directory to DIR. The default DIR is the value of the
HOME shell variable.
The variable CDPATH defines the search path for the directory containing
DIR. Alternative directory names in CDPATH are separated by a colon (:).
A null directory name is the same as the current directory. If DIR begins
with a slash (/), then CDPATH is not used.
If the directory is not found, and the shell option `cdable_vars' is set,
the word is assumed to be a variable name. If that variable has a value,
its value is used for DIR.
Options:
-L force symbolic links to be followed: resolve symbolic
links in DIR after processing instances of `..'
-P use the physical directory structure without following
symbolic links: resolve symbolic links in DIR before
processing instances of `..'
-e if the -P option is supplied, and the current working
directory cannot be determined successfully, exit with
a non-zero status
#if defined (O_XATTR)
-@ on systems that support it, present a file with extended
attributes as a directory containing the file attributes
#endif
The default is to follow symbolic links, as if `-L' were specified.
`..' is processed by removing the immediately previous pathname component
back to a slash or the beginning of DIR.
Exit Status:
Returns 0 if the directory is changed, and if $PWD is set successfully when
-P is used; non-zero otherwise.
$END
/* Just set $PWD, don't change OLDPWD. Used by `pwd -P' in posix mode. */
static int
setpwd (dirname)
char *dirname;
{
int old_anm;
SHELL_VAR *tvar;
old_anm = array_needs_making;
tvar = bind_variable ("PWD", dirname ? dirname : "", 0);
if (tvar && readonly_p (tvar))
return EXECUTION_FAILURE;
if (tvar && old_anm == 0 && array_needs_making && exported_p (tvar))
{
update_export_env_inplace ("PWD=", 4, dirname ? dirname : "");
array_needs_making = 0;
}
return EXECUTION_SUCCESS;
}
static int
bindpwd (no_symlinks)
int no_symlinks;
{
char *dirname, *pwdvar;
int old_anm, r;
SHELL_VAR *tvar;
r = sh_chkwrite (EXECUTION_SUCCESS);
#define tcwd the_current_working_directory
dirname = tcwd ? (no_symlinks ? sh_physpath (tcwd, 0) : tcwd)
: get_working_directory ("cd");
#undef tcwd
old_anm = array_needs_making;
pwdvar = get_string_value ("PWD");
tvar = bind_variable ("OLDPWD", pwdvar, 0);
if (tvar && readonly_p (tvar))
r = EXECUTION_FAILURE;
if (old_anm == 0 && array_needs_making && exported_p (tvar))
{
update_export_env_inplace ("OLDPWD=", 7, pwdvar);
array_needs_making = 0;
}
if (setpwd (dirname) == EXECUTION_FAILURE)
r = EXECUTION_FAILURE;
if (dirname == 0 && eflag)
r = EXECUTION_FAILURE;
if (dirname && dirname != the_current_working_directory)
free (dirname);
return (r);
}
/* Call get_working_directory to reset the value of
the_current_working_directory () */
static char *
resetpwd (caller)
char *caller;
{
char *tdir;
FREE (the_current_working_directory);
the_current_working_directory = (char *)NULL;
tdir = get_working_directory (caller);
return (tdir);
}
static int
cdxattr (dir, ndirp)
char *dir; /* don't assume we can always free DIR */
char **ndirp; /* return new constructed directory name */
{
#if defined (O_XATTR)
int apfd, fd, r, e;
char buf[11+40+40]; /* construct new `fake' path for pwd */
apfd = openat (AT_FDCWD, dir, O_RDONLY|O_NONBLOCK);
if (apfd < 0)
return -1;
fd = openat (apfd, ".", O_XATTR);
e = errno;
close (apfd); /* ignore close error for now */
errno = e;
if (fd < 0)
return -1;
r = fchdir (fd); /* assume fchdir exists everywhere with O_XATTR */
if (r < 0)
{
close (fd);
return -1;
}
/* NFSv4 and ZFS extended attribute directories do not have names which are
visible in the standard Unix directory tree structure. To ensure we have
a valid name for $PWD, we synthesize one under /proc, but to keep that
path valid, we need to keep the file descriptor open as long as we are in
this directory. This imposes a certain structure on /proc. */
if (ndirp)
{
sprintf (buf, "/proc/%d/fd/%d", getpid(), fd);
*ndirp = savestring (buf);
}
if (xattrfd >= 0)
close (xattrfd);
xattrfd = fd;
return r;
#else
return -1;
#endif
}
/* Clean up the O_XATTR baggage. Currently only closes xattrfd */
static void
resetxattr ()
{
#if defined (O_XATTR)
if (xattrfd >= 0)
{
close (xattrfd);
xattrfd = -1;
}
#else
xattrfd = -1; /* not strictly necessary */
#endif
}
#define LCD_DOVARS 0x001
#define LCD_DOSPELL 0x002
#define LCD_PRINTPATH 0x004
#define LCD_FREEDIRNAME 0x008
/* This builtin is ultimately the way that all user-visible commands should
change the current working directory. It is called by cd_to_string (),
so the programming interface is simple, and it handles errors and
restrictions properly. */
int
cd_builtin (list)
WORD_LIST *list;
{
char *dirname, *cdpath, *path, *temp;
int path_index, no_symlinks, opt, lflag, e;
#if defined (RESTRICTED_SHELL)
if (restricted)
{
sh_restricted ((char *)NULL);
return (EXECUTION_FAILURE);
}
#endif /* RESTRICTED_SHELL */
eflag = 0;
no_symlinks = no_symbolic_links;
xattrflag = 0;
reset_internal_getopt ();
#if defined (O_XATTR)
while ((opt = internal_getopt (list, "eLP@")) != -1)
#else
while ((opt = internal_getopt (list, "eLP")) != -1)
#endif
{
switch (opt)
{
case 'P':
no_symlinks = 1;
break;
case 'L':
no_symlinks = 0;
break;
case 'e':
eflag = 1;
break;
#if defined (O_XATTR)
case '@':
xattrflag = 1;
break;
#endif
CASE_HELPOPT;
default:
builtin_usage ();
return (EX_USAGE);
}
}
list = loptend;
lflag = (cdable_vars ? LCD_DOVARS : 0) |
((interactive && cdspelling) ? LCD_DOSPELL : 0);
if (eflag && no_symlinks == 0)
eflag = 0;
if (list == 0)
{
/* `cd' without arguments is equivalent to `cd $HOME' */
dirname = get_string_value ("HOME");
if (dirname == 0)
{
builtin_error (_("HOME not set"));
return (EXECUTION_FAILURE);
}
lflag = 0;
}
#if defined (CD_COMPLAINS)
else if (list->next)
{
builtin_error (_("too many arguments"));
return (EXECUTION_FAILURE);
}
#endif
#if 0
else if (list->word->word[0] == '\0')
{
builtin_error (_("null directory"));
return (EXECUTION_FAILURE);
}
#endif
else if (list->word->word[0] == '-' && list->word->word[1] == '\0')
{
/* This is `cd -', equivalent to `cd $OLDPWD' */
dirname = get_string_value ("OLDPWD");
if (dirname == 0)
{
builtin_error (_("OLDPWD not set"));
return (EXECUTION_FAILURE);
}
#if 0
lflag = interactive ? LCD_PRINTPATH : 0;
#else
lflag = LCD_PRINTPATH; /* According to SUSv3 */
#endif
}
else if (absolute_pathname (list->word->word))
dirname = list->word->word;
else if (privileged_mode == 0 && (cdpath = get_string_value ("CDPATH")))
{
dirname = list->word->word;
/* Find directory in $CDPATH. */
path_index = 0;
while (path = extract_colon_unit (cdpath, &path_index))
{
/* OPT is 1 if the path element is non-empty */
opt = path[0] != '\0';
temp = sh_makepath (path, dirname, MP_DOTILDE);
free (path);
if (change_to_directory (temp, no_symlinks, xattrflag))
{
/* POSIX.2 says that if a nonempty directory from CDPATH
is used to find the directory to change to, the new
directory name is echoed to stdout, whether or not
the shell is interactive. */
if (opt && (path = no_symlinks ? temp : the_current_working_directory))
printf ("%s\n", path);
free (temp);
#if 0
/* Posix.2 says that after using CDPATH, the resultant
value of $PWD will not contain `.' or `..'. */
return (bindpwd (posixly_correct || no_symlinks));
#else
return (bindpwd (no_symlinks));
#endif
}
else
free (temp);
}
#if 0
/* changed for bash-4.2 Posix cd description steps 5-6 */
/* POSIX.2 says that if `.' does not appear in $CDPATH, we don't
try the current directory, so we just punt now with an error
message if POSIXLY_CORRECT is non-zero. The check for cdpath[0]
is so we don't mistakenly treat a CDPATH value of "" as not
specifying the current directory. */
if (posixly_correct && cdpath[0])
{
builtin_error ("%s: %s", dirname, strerror (ENOENT));
return (EXECUTION_FAILURE);
}
#endif
}
else
dirname = list->word->word;
/* When we get here, DIRNAME is the directory to change to. If we
chdir successfully, just return. */
if (change_to_directory (dirname, no_symlinks, xattrflag))
{
if (lflag & LCD_PRINTPATH)
printf ("%s\n", dirname);
return (bindpwd (no_symlinks));
}
/* If the user requests it, then perhaps this is the name of
a shell variable, whose value contains the directory to
change to. */
if (lflag & LCD_DOVARS)
{
temp = get_string_value (dirname);
if (temp && change_to_directory (temp, no_symlinks, xattrflag))
{
printf ("%s\n", temp);
return (bindpwd (no_symlinks));
}
}
/* If the user requests it, try to find a directory name similar in
spelling to the one requested, in case the user made a simple
typo. This is similar to the UNIX 8th and 9th Edition shells. */
if (lflag & LCD_DOSPELL)
{
temp = dirspell (dirname);
if (temp && change_to_directory (temp, no_symlinks, xattrflag))
{
printf ("%s\n", temp);
free (temp);
return (bindpwd (no_symlinks));
}
else
FREE (temp);
}
e = errno;
temp = printable_filename (dirname, 0);
builtin_error ("%s: %s", temp, strerror (e));
if (temp != dirname)
free (temp);
return (EXECUTION_FAILURE);
}
$BUILTIN pwd
$FUNCTION pwd_builtin
$SHORT_DOC pwd [-LP]
Print the name of the current working directory.
Options:
-L print the value of $PWD if it names the current working
directory
-P print the physical directory, without any symbolic links
By default, `pwd' behaves as if `-L' were specified.
Exit Status:
Returns 0 unless an invalid option is given or the current directory
cannot be read.
$END
/* Non-zero means that pwd always prints the physical directory, without
symbolic links. */
static int verbatim_pwd;
/* Print the name of the current working directory. */
int
pwd_builtin (list)
WORD_LIST *list;
{
char *directory;
int opt, pflag;
verbatim_pwd = no_symbolic_links;
pflag = 0;
reset_internal_getopt ();
while ((opt = internal_getopt (list, "LP")) != -1)
{
switch (opt)
{
case 'P':
verbatim_pwd = pflag = 1;
break;
case 'L':
verbatim_pwd = 0;
break;
CASE_HELPOPT;
default:
builtin_usage ();
return (EX_USAGE);
}
}
list = loptend;
#define tcwd the_current_working_directory
directory = tcwd ? (verbatim_pwd ? sh_physpath (tcwd, 0) : tcwd)
: get_working_directory ("pwd");
/* Try again using getcwd() if canonicalization fails (for instance, if
the file system has changed state underneath bash). */
if ((tcwd && directory == 0) ||
(posixly_correct && same_file (".", tcwd, (struct stat *)0, (struct stat *)0) == 0))
{
if (directory && directory != tcwd)
free (directory);
directory = resetpwd ("pwd");
}
#undef tcwd
if (directory)
{
opt = EXECUTION_SUCCESS;
printf ("%s\n", directory);
/* This is dumb but posix-mandated. */
if (posixly_correct && pflag)
opt = setpwd (directory);
if (directory != the_current_working_directory)
free (directory);
return (sh_chkwrite (opt));
}
else
return (EXECUTION_FAILURE);
}
/* Do the work of changing to the directory NEWDIR. Handle symbolic
link following, etc. This function *must* return with
the_current_working_directory either set to NULL (in which case
getcwd() will eventually be called), or set to a string corresponding
to the working directory. Return 1 on success, 0 on failure. */
static int
change_to_directory (newdir, nolinks, xattr)
char *newdir;
int nolinks, xattr;
{
char *t, *tdir, *ndir;
int err, canon_failed, r, ndlen, dlen;
tdir = (char *)NULL;
if (the_current_working_directory == 0)
{
t = get_working_directory ("chdir");
FREE (t);
}
t = make_absolute (newdir, the_current_working_directory);
/* TDIR is either the canonicalized absolute pathname of NEWDIR
(nolinks == 0) or the absolute physical pathname of NEWDIR
(nolinks != 0). */
tdir = nolinks ? sh_physpath (t, 0)
: sh_canonpath (t, PATH_CHECKDOTDOT|PATH_CHECKEXISTS);
ndlen = strlen (newdir);
dlen = strlen (t);
/* Use the canonicalized version of NEWDIR, or, if canonicalization
failed, use the non-canonical form. */
canon_failed = 0;
if (tdir && *tdir)
free (t);
else
{
FREE (tdir);
tdir = t;
canon_failed = 1;
}
/* In POSIX mode, if we're resolving symlinks logically and sh_canonpath
returns NULL (because it checks the path, it will return NULL if the
resolved path doesn't exist), fail immediately. */
if (posixly_correct && nolinks == 0 && canon_failed && (errno != ENAMETOOLONG || ndlen > PATH_MAX))
{
#if defined ENAMETOOLONG
if (errno != ENOENT && errno != ENAMETOOLONG)
#else
if (errno != ENOENT)
#endif
errno = ENOTDIR;
free (tdir);
return (0);
}
#if defined (O_XATTR)
if (xattrflag)
{
r = cdxattr (nolinks ? newdir : tdir, &ndir);
if (r >= 0)
{
canon_failed = 0;
free (tdir);
tdir = ndir;
}
else
{
err = errno;
free (tdir);
errno = err;
return (0); /* no xattr */
}
}
else
#endif
{
r = chdir (nolinks ? newdir : tdir);
if (r >= 0)
resetxattr ();
}
/* If the chdir succeeds, update the_current_working_directory. */
if (r == 0)
{
/* If canonicalization failed, but the chdir succeeded, reset the
shell's idea of the_current_working_directory. */
if (canon_failed)
{
t = resetpwd ("cd");
if (t == 0)
set_working_directory (tdir);
else
free (t);
}
else
set_working_directory (tdir);
free (tdir);
return (1);
}
/* We failed to change to the appropriate directory name. If we tried
what the user passed (nolinks != 0), punt now. */
if (nolinks)
{
free (tdir);
return (0);
}
err = errno;
/* We're not in physical mode (nolinks == 0), but we failed to change to
the canonicalized directory name (TDIR). Try what the user passed
verbatim. If we succeed, reinitialize the_current_working_directory. */
if (chdir (newdir) == 0)
{
t = resetpwd ("cd");
if (t == 0)
set_working_directory (tdir);
else
free (t);
r = 1;
}
else
{
errno = err;
r = 0;
}
free (tdir);
return r;
}