* modules/symlinkat: New file.
* lib/symlinkat.c: Likewise.
* m4/symlinkat.m4 (gl_FUNC_SYMLINKAT): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Add witnesses.
* modules/unistd (Makefile.am): Use them.
* lib/unistd.in.h (symlinkat, readlinkat): Declare them.
(faccessat) [GNULIB_POSIXCHECK]: Fix typo.
* lib/at-func.c (FUNC_RESULT): New macro, defaulting to int.
* MODULES.html.sh (File system functions): Mention module.
* doc/posix-functions/symlinkat.texi (symlinkat): Likewise.
* doc/posix-functions/readlinkat.texi (readlinkat): Likewise.
* modules/symlinkat-tests: New test.
* tests/test-symlinkat.c: Likewise.
Signed-off-by: Eric Blake <ebb9@byu.net>
2009-09-05 Eric Blake <ebb9@byu.net>
+ symlinkat: new module
+ * modules/symlinkat: New file.
+ * lib/symlinkat.c: Likewise.
+ * m4/symlinkat.m4 (gl_FUNC_SYMLINKAT): Likewise.
+ * m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Add witnesses.
+ * modules/unistd (Makefile.am): Use them.
+ * lib/unistd.in.h (symlinkat, readlinkat): Declare them.
+ (faccessat) [GNULIB_POSIXCHECK]: Fix typo.
+ * lib/at-func.c (FUNC_RESULT): New macro, defaulting to int.
+ * MODULES.html.sh (File system functions): Mention module.
+ * doc/posix-functions/symlinkat.texi (symlinkat): Likewise.
+ * doc/posix-functions/readlinkat.texi (readlinkat): Likewise.
+ * modules/symlinkat-tests: New test.
+ * tests/test-symlinkat.c: Likewise.
+
test-openat-safer: add more checks
* tests/test-openat-safer.c (main): Check more code paths.
faccessat: new module
* modules/faccessat: New file.
- * lib/faccessat.m4: Likewise.
+ * lib/faccessat.c: Likewise.
* m4/faccessat.m4 (gl_FUNC_FACCESSAT): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Add witness.
* modules/unistd (Makefile.am): Use it.
func_module savewd
func_module stat-macros
func_module stat-time
+ func_module symlinkat
func_module tmpdir
func_module unlinkdir
func_module utimecmp
POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/readlinkat.html}
-Gnulib module: ---
+Gnulib module: readlinkat
Portability problems fixed by Gnulib:
@itemize
+@item
+This function is missing on some platforms:
+glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
+5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
@item
-This function is missing on some platforms:
-glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
-5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
+This function always fails on platforms that don't support symlinks:
+mingw
+@item
+When @code{readlink} is called on a directory: In the case of NFS mounted
+directories, Cygwin sets @code{errno} to @code{ENOENT} or @code{EIO} instead of
+@code{EINVAL}. To avoid this problem, check for a directory before calling
+@code{readlink}.
+@item
+When @code{readlink} is called on a file that is not a symbolic link:
+Irix may set @code{errno} to @code{ENXIO} instead of @code{EINVAL}. Cygwin
+may set errno to @code{EACCES} instead of @code{EINVAL}.
@end itemize
POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/symlinkat.html}
-Gnulib module: ---
+Gnulib module: symlinkat
Portability problems fixed by Gnulib:
@itemize
+@item
+This function is missing on some platforms:
+glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
+5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
@item
-This function is missing on some platforms:
-glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
-5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
+This function always fails with @samp{ENOSYS} on platforms that don't
+support symlinks:
+mingw
@end itemize
# define VALIDATE_FLAG(F) /* empty */
#endif
+#ifdef AT_FUNC_RESULT
+# define FUNC_RESULT AT_FUNC_RESULT
+#else
+# define FUNC_RESULT int
+#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;
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. */
-int
+FUNC_RESULT
AT_FUNC_NAME (int fd, char const *file AT_FUNC_POST_FILE_PARAM_DECLS)
{
+ /* Be careful to choose names unlikely to conflict with
+ AT_FUNC_POST_FILE_PARAM_DECLS. */
struct saved_cwd saved_cwd;
int saved_errno;
- int err;
+ FUNC_RESULT err;
VALIDATE_FLAG (flag);
return CALL_FUNC (file);
{
- char buf[OPENAT_BUFFER_SIZE];
- char *proc_file = openat_proc_name (buf, fd, file);
+ char proc_buf[OPENAT_BUFFER_SIZE];
+ char *proc_file = openat_proc_name (proc_buf, fd, file);
if (proc_file)
{
- int proc_result = CALL_FUNC (proc_file);
+ FUNC_RESULT proc_result = CALL_FUNC (proc_file);
int proc_errno = errno;
- if (proc_file != buf)
+ if (proc_file != proc_buf)
free (proc_file);
/* If the syscall succeeds, or if it fails with an unexpected
errno value, then return right away. Otherwise, fall through
return err;
}
#undef CALL_FUNC
+#undef FUNC_RESULT
--- /dev/null
+/* Create a symlink relative to an open directory.
+ 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 */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
+#include "openat.h"
+#include "openat-priv.h"
+#include "save-cwd.h"
+
+#if !HAVE_SYMLINK
+/* Mingw lacks symlink, so this wrapper is trivial. */
+
+# include <errno.h>
+
+int
+symlinkat (char const *path1 _UNUSED_PARAMETER_, int fd _UNUSED_PARAMETER_,
+ char const *path2 _UNUSED_PARAMETER_)
+{
+ errno = ENOSYS;
+ return -1;
+}
+
+#else /* HAVE_SYMLINK */
+
+/* Our openat helper functions expect the directory parameter first,
+ not second. These shims make life easier. */
+
+/* Like symlink, but with arguments reversed. */
+static int
+symlink_reversed (char const *file, char const *contents)
+{
+ return symlink (contents, file);
+}
+
+/* Like symlinkat, but with arguments reversed. */
+
+static int
+symlinkat_reversed (int fd, char const *file, char const *contents);
+
+# define AT_FUNC_NAME symlinkat_reversed
+# define AT_FUNC_F1 symlink_reversed
+# define AT_FUNC_POST_FILE_PARAM_DECLS , char const *contents
+# define AT_FUNC_POST_FILE_ARGS , contents
+# 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
+
+/* Create a symlink FILE, in the directory open on descriptor FD,
+ holding CONTENTS. If possible, do it without changing the
+ working directory. Otherwise, resort to using save_cwd/fchdir,
+ then mkdir/restore_cwd. If either the save_cwd or the restore_cwd
+ fails, then give a diagnostic and exit nonzero. */
+
+int
+symlinkat (char const *contents, int fd, char const *file)
+{
+ return symlinkat_reversed (fd, file, contents);
+}
+
+#endif /* HAVE_SYMLINK */
+
+/* Gnulib provides a readlink stub for mingw; use it for distinction
+ between EINVAL and ENOENT, rather than always failing with ENOSYS. */
+
+/* POSIX 2008 says that unlike readlink, readlinkat returns 0 for
+ success instead of the buffer length. But this would render
+ readlinkat worthless since readlink does not guarantee a
+ NUL-terminated buffer. Assume this was a bug in POSIX. */
+
+/* Read the contents of symlink FILE into buffer BUF of size LEN, in the
+ directory open on descriptor FD. If possible, do it without changing
+ the working directory. Otherwise, resort to using save_cwd/fchdir,
+ then mkdir/restore_cwd. If either the save_cwd or the restore_cwd
+ fails, then give a diagnostic and exit nonzero. */
+
+#define AT_FUNC_NAME readlinkat
+#define AT_FUNC_F1 readlink
+#define AT_FUNC_POST_FILE_PARAM_DECLS , char *buf, size_t len
+#define AT_FUNC_POST_FILE_ARGS , buf, len
+#define AT_FUNC_RESULT ssize_t
+#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
# define faccessat(d,n,m,f) \
(GL_LINK_WARNING ("faccessat is not portable - " \
"use gnulib module faccessat for portability"), \
- fchownat (d, n, m, f))
+ faccessat (d, n, m, f))
#endif
+#if @GNULIB_SYMLINKAT@
+# if !@HAVE_SYMLINKAT@
+int symlinkat (char const *contents, int fd, char const *file);
+# endif
+# if !@HAVE_READLINKAT@
+ssize_t readlinkat (int fd, char const *file, char *buf, size_t len);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef symlinkat
+# define symlinkat(c,d,n) \
+ (GL_LINK_WARNING ("symlinkat is not portable - " \
+ "use gnulib module symlinkat for portability"), \
+ symlinkat (c, d, n))
+# undef readlinkat
+# define readlinkat(d,n,b,l) \
+ (GL_LINK_WARNING ("faccessat is not portable - " \
+ "use gnulib module symlinkat for portability"), \
+ readlinkat (d, n, b, l))
+#endif
#if @GNULIB_CLOSE@
# if @REPLACE_CLOSE@
--- /dev/null
+# serial 1
+# See if we need to provide symlinkat/readlinkat replacement.
+
+dnl Copyright (C) 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Written by Eric Blake.
+
+AC_DEFUN([gl_FUNC_SYMLINKAT],
+[
+ AC_REQUIRE([gl_FUNC_OPENAT])
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+ AC_CHECK_FUNCS_ONCE([symlink symlinkat readlinkat])
+ if test $ac_cv_func_symlinkat = no; then
+ # No known system has readlinkat but not symlinkat
+ HAVE_SYMLINKAT=0
+ HAVE_READLINKAT=0
+ AC_LIBOBJ([symlinkat])
+ fi
+])
GNULIB_PIPE2=0; AC_SUBST([GNULIB_PIPE2])
GNULIB_READLINK=0; AC_SUBST([GNULIB_READLINK])
GNULIB_SLEEP=0; AC_SUBST([GNULIB_SLEEP])
+ GNULIB_SYMLINKAT=0; AC_SUBST([GNULIB_SYMLINKAT])
GNULIB_UNISTD_H_GETOPT=0; AC_SUBST([GNULIB_UNISTD_H_GETOPT])
GNULIB_UNISTD_H_SIGPIPE=0; AC_SUBST([GNULIB_UNISTD_H_SIGPIPE])
GNULIB_WRITE=0; AC_SUBST([GNULIB_WRITE])
HAVE_LINK=1; AC_SUBST([HAVE_LINK])
HAVE_PIPE2=1; AC_SUBST([HAVE_PIPE2])
HAVE_READLINK=1; AC_SUBST([HAVE_READLINK])
+ HAVE_READLINKAT=1; AC_SUBST([HAVE_READLINKAT])
HAVE_SLEEP=1; AC_SUBST([HAVE_SLEEP])
+ HAVE_SYMLINKAT=1; AC_SUBST([HAVE_SYMLINKAT])
HAVE_DECL_ENVIRON=1; AC_SUBST([HAVE_DECL_ENVIRON])
HAVE_DECL_GETLOGIN_R=1; AC_SUBST([HAVE_DECL_GETLOGIN_R])
HAVE_OS_H=0; AC_SUBST([HAVE_OS_H])
--- /dev/null
+Description:
+symlinkat() and readlinkat(): manage symlinks relative to a directory
+
+Files:
+lib/symlinkat.c
+m4/symlinkat.m4
+
+Depends-on:
+extensions
+fcntl-h
+openat
+readlink
+unistd
+
+configure.ac:
+gl_FUNC_SYMLINKAT
+gl_UNISTD_MODULE_INDICATOR([symlinkat])
+
+Makefile.am:
+
+Include:
+<fcntl.h>
+<unistd.h>
+
+License:
+GPL
+
+Maintainer:
+Jim Meyering, Eric Blake
--- /dev/null
+Files:
+tests/test-symlinkat.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-symlinkat
+check_PROGRAMS += test-symlinkat
+test_symlinkat_LDADD = $(LDADD) @LIBINTL@
-e 's|@''GNULIB_PIPE2''@|$(GNULIB_PIPE2)|g' \
-e 's|@''GNULIB_READLINK''@|$(GNULIB_READLINK)|g' \
-e 's|@''GNULIB_SLEEP''@|$(GNULIB_SLEEP)|g' \
+ -e 's|@''GNULIB_SYMLINKAT''@|$(GNULIB_SYMLINKAT)|g' \
-e 's|@''GNULIB_UNISTD_H_GETOPT''@|$(GNULIB_UNISTD_H_GETOPT)|g' \
-e 's|@''GNULIB_UNISTD_H_SIGPIPE''@|$(GNULIB_UNISTD_H_SIGPIPE)|g' \
-e 's|@''GNULIB_WRITE''@|$(GNULIB_WRITE)|g' \
-e 's|@''HAVE_LINK''@|$(HAVE_LINK)|g' \
-e 's|@''HAVE_PIPE2''@|$(HAVE_PIPE2)|g' \
-e 's|@''HAVE_READLINK''@|$(HAVE_READLINK)|g' \
+ -e 's|@''HAVE_READLINKAT''@|$(HAVE_READLINKAT)|g' \
-e 's|@''HAVE_SLEEP''@|$(HAVE_SLEEP)|g' \
+ -e 's|@''HAVE_SYMLINKAT''@|$(HAVE_SYMLINKAT)|g' \
-e 's|@''HAVE_UNLINKAT''@|$(HAVE_UNLINKAT)|g' \
-e 's|@''HAVE_DECL_ENVIRON''@|$(HAVE_DECL_ENVIRON)|g' \
-e 's|@''HAVE_DECL_GETLOGIN_R''@|$(HAVE_DECL_GETLOGIN_R)|g' \
--- /dev/null
+/* Tests of symlinkat and readlinkat.
+ 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 <unistd.h>
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#ifndef HAVE_SYMLINK
+# define HAVE_SYMLINK 0
+#endif
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+int
+main ()
+{
+ char buf[80];
+
+ /* Create handle for future use. */
+ int dfd = openat (AT_FDCWD, ".", O_RDONLY);
+ ASSERT (0 <= dfd);
+
+ /* Sanity checks of failures. Mingw lacks symlinkat, but readlinkat
+ can still distinguish between various errors. */
+ errno = 0;
+ ASSERT (readlinkat (AT_FDCWD, "no_such", buf, sizeof buf) == -1);
+ ASSERT (errno == ENOENT);
+ errno = 0;
+ ASSERT (readlinkat (dfd, "no_such", buf, sizeof buf) == -1);
+ ASSERT (errno == ENOENT);
+ errno = 0;
+ ASSERT (readlinkat (AT_FDCWD, "", buf, sizeof buf) == -1);
+ ASSERT (errno == ENOENT);
+ errno = 0;
+ ASSERT (readlinkat (dfd, "", buf, sizeof buf) == -1);
+ ASSERT (errno == ENOENT);
+ errno = 0;
+ ASSERT (readlinkat (AT_FDCWD, ".", buf, sizeof buf) == -1);
+ ASSERT (errno == EINVAL);
+ errno = 0;
+ ASSERT (readlinkat (dfd, ".", buf, sizeof buf) == -1);
+ ASSERT (errno == EINVAL);
+ errno = 0;
+ ASSERT (symlinkat ("who cares", AT_FDCWD, "") == -1);
+ ASSERT (errno == ENOENT || errno == ENOSYS);
+ errno = 0;
+ ASSERT (symlinkat ("who cares", dfd, "") == -1);
+ ASSERT (errno == ENOENT || errno == ENOSYS);
+
+ /* Skip everything else on mingw. */
+ if (HAVE_SYMLINK)
+ {
+ const char *linkname = "test-symlinkat.link";
+ const char *contents = "don't matter!";
+ int exp = strlen (contents);
+
+ /* Create link while cwd is '.', then read it in '..'. */
+ ASSERT (symlinkat (contents, AT_FDCWD, linkname) == 0);
+ errno = 0;
+ ASSERT (symlinkat (contents, dfd, linkname) == -1);
+ ASSERT (errno == EEXIST);
+ ASSERT (chdir ("..") == 0);
+ errno = 0;
+ ASSERT (readlinkat (AT_FDCWD, linkname, buf, sizeof buf) == -1);
+ ASSERT (errno == ENOENT);
+ ASSERT (readlinkat (dfd, linkname, buf, sizeof buf) == exp);
+ ASSERT (strncmp (contents, buf, exp) == 0);
+ ASSERT (unlinkat (dfd, linkname, 0) == 0);
+
+ /* Create link while cwd is '..', then read it in '.'. */
+ ASSERT (symlinkat (contents, dfd, linkname) == 0);
+ ASSERT (fchdir (dfd) == 0);
+ errno = 0;
+ ASSERT (symlinkat (contents, AT_FDCWD, linkname) == -1);
+ ASSERT (errno == EEXIST);
+ buf[0] = '\0';
+ ASSERT (readlinkat (AT_FDCWD, linkname, buf, sizeof buf) == exp);
+ ASSERT (strncmp (contents, buf, exp) == 0);
+ buf[0] = '\0';
+ ASSERT (readlinkat (dfd, linkname, buf, sizeof buf) == exp);
+ ASSERT (strncmp (contents, buf, exp) == 0);
+ ASSERT (unlink (linkname) == 0);
+ }
+
+ ASSERT (close (dfd) == 0);
+
+ return 0;
+}
projects / gnulib.git / commitdiff