* lib/at-func.c (FUNC_FAIL): New define.
(AT_FUNC_NAME, VALIDATE_FLAG): Use it rather than raw -1.
* modules/areadlinkat: New module.
* lib/linkat.c (areadlinkat): Move...
* lib/areadlinkat.c (areadlinkat): ...to new file.
* lib/areadlink.h (areadlinkat): Declare it.
* modules/linkat (Depends-on): Add areadlinkat.
* MODULES.html.sh (File system functions): Mention it.
* modules/areadlinkat-tests: New test.
* tests/test-areadlinkat.c: New file.
Signed-off-by: Eric Blake <ebb9@byu.net>
2009-10-07 Eric Blake <ebb9@byu.net>
+ areadlinkat: new module
+ * lib/at-func.c (FUNC_FAIL): New define.
+ (AT_FUNC_NAME, VALIDATE_FLAG): Use it rather than raw -1.
+ * modules/areadlinkat: New module.
+ * lib/linkat.c (areadlinkat): Move...
+ * lib/areadlinkat.c (areadlinkat): ...to new file.
+ * lib/areadlink.h (areadlinkat): Declare it.
+ * modules/linkat (Depends-on): Add areadlinkat.
+ * MODULES.html.sh (File system functions): Mention it.
+ * modules/areadlinkat-tests: New test.
+ * tests/test-areadlinkat.c: New file.
+
areadlink, areadlink-with-size: add tests
* modules/areadlink-tests: New test.
* modules/areadlink-with-size-tests: Likewise.
func_module acl
func_module areadlink
func_module areadlink-with-size
+ func_module areadlinkat
func_module backupfile
func_module canonicalize
func_module canonicalize-lgpl
/* Read symbolic links without size limitation.
- Copyright (C) 2001, 2003, 2004, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2003, 2004, 2007, 2009 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
extern char *areadlink (char const *filename);
extern char *areadlink_with_size (char const *filename, size_t size_hint);
+
+#if GNULIB_AREADLINKAT
+extern char *areadlinkat (int fd, char const *filename);
+#endif
--- /dev/null
+/* areadlink.c -- readlink wrapper to return the link name in malloc'd storage
+ Unlike xreadlinkat, only call exit on failure to change directory.
+
+ Copyright (C) 2001, 2003-2007, 2009 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 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
+ 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, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Jim Meyering <jim@meyering.net>,
+ and Bruno Haible <bruno@clisp.org>,
+ and Eric Blake <ebb9@byu.net>. */
+
+#include <config.h>
+
+/* Specification. */
+#include "areadlink.h"
+
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+#if HAVE_READLINKAT
+
+/* Call readlinkat to get the symbolic link value of FILENAME relative to FD.
+ Return a pointer to that NUL-terminated string in malloc'd storage.
+ If readlinkat fails, return NULL and set errno (although failure to
+ change directory will issue a diagnostic and exit).
+ If realloc fails, or if the link value is longer than SIZE_MAX :-),
+ return NULL and set errno to ENOMEM. */
+
+char *
+areadlinkat (int fd, char const *filename)
+{
+ /* The initial buffer size for the link value. A power of 2
+ detects arithmetic overflow earlier, but is not required. */
+# define INITIAL_BUF_SIZE 1024
+
+ /* Allocate the initial buffer on the stack. This way, in the common
+ case of a symlink of small size, we get away with a single small malloc()
+ instead of a big malloc() followed by a shrinking realloc(). */
+ char initial_buf[INITIAL_BUF_SIZE];
+
+ char *buffer = initial_buf;
+ size_t buf_size = sizeof (initial_buf);
+
+ while (1)
+ {
+ /* Attempt to read the link into the current buffer. */
+ ssize_t link_length = readlinkat (fd, filename, buffer, buf_size);
+
+ /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
+ with errno == ERANGE if the buffer is too small. */
+ if (link_length < 0 && errno != ERANGE)
+ {
+ if (buffer != initial_buf)
+ {
+ int saved_errno = errno;
+ free (buffer);
+ errno = saved_errno;
+ }
+ return NULL;
+ }
+
+ if ((size_t) link_length < buf_size)
+ {
+ buffer[link_length++] = '\0';
+
+ /* Return it in a chunk of memory as small as possible. */
+ if (buffer == initial_buf)
+ {
+ buffer = (char *) malloc (link_length);
+ if (buffer == NULL)
+ /* errno is ENOMEM. */
+ return NULL;
+ memcpy (buffer, initial_buf, link_length);
+ }
+ else
+ {
+ /* Shrink buffer before returning it. */
+ if ((size_t) link_length < buf_size)
+ {
+ char *smaller_buffer = (char *) realloc (buffer, link_length);
+
+ if (smaller_buffer != NULL)
+ buffer = smaller_buffer;
+ }
+ }
+ return buffer;
+ }
+
+ if (buffer != initial_buf)
+ free (buffer);
+ buf_size *= 2;
+ if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
+ buffer = (char *) malloc (buf_size);
+ if (buffer == NULL)
+ /* errno is ENOMEM. */
+ return NULL;
+ }
+}
+
+#else /* !HAVE_READLINKAT */
+
+/* It is more efficient to change directories only once and call
+ areadlink, rather than repeatedly call the replacement
+ readlinkat. */
+
+# define AT_FUNC_NAME areadlinkat
+# define AT_FUNC_F1 areadlink
+# define AT_FUNC_POST_FILE_PARAM_DECLS /* empty */
+# define AT_FUNC_POST_FILE_ARGS /* empty */
+# define AT_FUNC_RESULT char *
+# define AT_FUNC_FAIL NULL
+# include "at-func.c"
+# undef AT_FUNC_NAME
+# undef AT_FUNC_F1
+# undef AT_FUNC_POST_FILE_PARAM_DECLS
+# undef AT_FUNC_POST_FILE_ARGS
+# undef AT_FUNC_RESULT
+# undef AT_FUNC_FAIL
+
+#endif /* !HAVE_READLINKAT */
if (flag & ~AT_FUNC_USE_F1_COND) \
{ \
errno = EINVAL; \
- return -1; \
+ return FUNC_FAIL; \
}
#else
# define CALL_FUNC(F) (AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS))
# define FUNC_RESULT int
#endif
+#ifdef AT_FUNC_FAIL
+# define FUNC_FAIL AT_FUNC_FAIL
+#else
+# define FUNC_FAIL -1
+#endif
+
/* Call AT_FUNC_F1 to operate on FILE, which is in the directory
open on descriptor FD. If AT_FUNC_USE_F1_COND is defined to a value,
AT_FUNC_POST_FILE_PARAM_DECLS must inlude a parameter named flag;
call AT_FUNC_F2 if FLAG is 0 or fail if FLAG contains more bits than
- AT_FUNC_USE_F1_COND. If possible, do it without changing the
+ AT_FUNC_USE_F1_COND. Return int and fail with -1 unless AT_FUNC_RESULT
+ or AT_FUNC_FAIL are defined. If possible, do it without changing the
working directory. Otherwise, resort to using save_cwd/fchdir,
then AT_FUNC_F?/restore_cwd. If either the save_cwd or the restore_cwd
fails, then give a diagnostic and exit nonzero. */
begin with. */
free_cwd (&saved_cwd);
errno = EBADF;
- return -1;
+ return FUNC_FAIL;
}
if (fchdir (fd) != 0)
saved_errno = errno;
free_cwd (&saved_cwd);
errno = saved_errno;
- return -1;
+ return FUNC_FAIL;
}
err = CALL_FUNC (file);
}
#undef CALL_FUNC
#undef FUNC_RESULT
+#undef FUNC_FAIL
# undef linkat
-/* Read a symlink, like areadlink, but relative to FD. */
-
-static char *
-areadlinkat (int fd, char const *filename)
-{
- /* The initial buffer size for the link value. A power of 2
- detects arithmetic overflow earlier, but is not required. */
-# define INITIAL_BUF_SIZE 1024
-
- /* Allocate the initial buffer on the stack. This way, in the common
- case of a symlink of small size, we get away with a single small malloc()
- instead of a big malloc() followed by a shrinking realloc(). */
- char initial_buf[INITIAL_BUF_SIZE];
-
- char *buffer = initial_buf;
- size_t buf_size = sizeof (initial_buf);
-
- while (1)
- {
- /* Attempt to read the link into the current buffer. */
- ssize_t link_length = readlinkat (fd, filename, buffer, buf_size);
-
- /* On AIX 5L v5.3 and HP-UX 11i v2 04/09, readlink returns -1
- with errno == ERANGE if the buffer is too small. */
- if (link_length < 0 && errno != ERANGE)
- {
- if (buffer != initial_buf)
- {
- int saved_errno = errno;
- free (buffer);
- errno = saved_errno;
- }
- return NULL;
- }
-
- if ((size_t) link_length < buf_size)
- {
- buffer[link_length++] = '\0';
-
- /* Return it in a chunk of memory as small as possible. */
- if (buffer == initial_buf)
- {
- buffer = (char *) malloc (link_length);
- if (buffer == NULL)
- /* errno is ENOMEM. */
- return NULL;
- memcpy (buffer, initial_buf, link_length);
- }
- else
- {
- /* Shrink buffer before returning it. */
- if ((size_t) link_length < buf_size)
- {
- char *smaller_buffer = (char *) realloc (buffer, link_length);
-
- if (smaller_buffer != NULL)
- buffer = smaller_buffer;
- }
- }
- return buffer;
- }
-
- if (buffer != initial_buf)
- free (buffer);
- buf_size *= 2;
- if (SSIZE_MAX < buf_size || (SIZE_MAX / 2 < SSIZE_MAX && buf_size == 0))
- {
- errno = ENOMEM;
- return NULL;
- }
- buffer = (char *) malloc (buf_size);
- if (buffer == NULL)
- /* errno is ENOMEM. */
- return NULL;
- }
-}
-
/* Create a link. If FILE1 is a symlink, create a hardlink to the
canonicalized file. */
--- /dev/null
+Description:
+Reading symbolic links without size limitation, relative to fd.
+
+Files:
+lib/areadlink.h
+lib/areadlinkat.c
+
+Depends-on:
+areadlink
+stdint
+symlinkat
+
+configure.ac:
+gl_MODULE_INDICATOR([areadlinkat])
+
+Makefile.am:
+lib_SOURCES += areadlinkat.c
+
+Include:
+"areadlink.h"
+
+License:
+GPL
+
+Maintainer:
+Jim Meyering, Eric Blake
--- /dev/null
+Files:
+tests/test-areadlink.h
+tests/test-areadlinkat.c
+
+Depends-on:
+stdbool
+symlink
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-areadlinkat
+check_PROGRAMS += test-areadlinkat
+test_areadlinkat_LDADD = $(LDADD) @LIBINTL@
Depends-on:
areadlink
+areadlinkat
dirname
errno
extensions
ASSERT (errno == EINVAL);
{
/* Too small a guess is okay. */
- size_t len = strlen (BASE "dir");
char *buf = func (BASE "link", 1);
ASSERT (buf);
ASSERT (strcmp (buf, BASE "dir") == 0);
--- /dev/null
+/* Tests of areadlinkat.
+ Copyright (C) 2009 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 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
+ 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, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009. */
+
+#include <config.h>
+
+#include "areadlink.h"
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+#define BASE "test-areadlinkat.t"
+
+#include "test-areadlink.h"
+
+static int dfd = AT_FDCWD;
+
+/* Wrapper for testing areadlinkat. */
+static char *
+do_areadlinkat (char const *name, size_t ignored _UNUSED_PARAMETER_)
+{
+ return areadlinkat (dfd, name);
+}
+
+int
+main ()
+{
+ int result;
+
+ /* Remove any leftovers from a previous partial run. */
+ ASSERT (system ("rm -rf " BASE "*") == 0);
+
+ /* Basic tests. */
+ result = test_areadlink (do_areadlinkat, false);
+ dfd = open (".", O_RDONLY);
+ ASSERT (0 <= dfd);
+ ASSERT (test_areadlink (do_areadlinkat, false) == result);
+
+ /* Relative tests. */
+ if (result == 77)
+ fputs ("skipping test: symlinks not supported on this filesystem\n",
+ stderr);
+ else
+ {
+ char *buf;
+ ASSERT (symlink ("nowhere", BASE "link") == 0);
+ ASSERT (mkdir (BASE "dir", 0700) == 0);
+ ASSERT (chdir (BASE "dir") == 0);
+ buf = areadlinkat (dfd, BASE "link");
+ ASSERT (buf);
+ ASSERT (strcmp (buf, "nowhere") == 0);
+ free (buf);
+ errno = 0;
+ ASSERT (areadlinkat (-1, BASE "link") == NULL);
+ ASSERT (errno == EBADF);
+ errno = 0;
+ ASSERT (areadlinkat (AT_FDCWD, BASE "link") == NULL);
+ ASSERT (errno == ENOENT);
+ ASSERT (chdir ("..") == 0);
+ ASSERT (rmdir (BASE "dir") == 0);
+ ASSERT (unlink (BASE "link") == 0);
+ }
+
+ ASSERT (close (dfd) == 0);
+ return result;
+}
projects / pspp / commitdiff