summaryrefslogtreecommitdiff
path: root/lib/careadlinkat.h
diff options
context:
space:
mode:
Diffstat (limited to 'lib/careadlinkat.h')
-rw-r--r--lib/careadlinkat.h67
1 files changed, 67 insertions, 0 deletions
diff --git a/lib/careadlinkat.h b/lib/careadlinkat.h
new file mode 100644
index 0000000..84ede3e
--- /dev/null
+++ b/lib/careadlinkat.h
@@ -0,0 +1,67 @@
+/* Read symbolic links into a buffer without size limitation, relative to fd.
+
+ Copyright (C) 2011-2016 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 Paul Eggert, Bruno Haible, and Jim Meyering. */
+
+#ifndef _GL_CAREADLINKAT_H
+#define _GL_CAREADLINKAT_H
+
+#include <fcntl.h>
+#include <unistd.h>
+
+struct allocator;
+
+/* Assuming the current directory is FD, get the symbolic link value
+ of FILENAME as a null-terminated string and put it into a buffer.
+ If FD is AT_FDCWD, FILENAME is interpreted relative to the current
+ working directory, as in openat.
+
+ If the link is small enough to fit into BUFFER put it there.
+ BUFFER's size is BUFFER_SIZE, and BUFFER can be null
+ if BUFFER_SIZE is zero.
+
+ If the link is not small, put it into a dynamically allocated
+ buffer managed by ALLOC. It is the caller's responsibility to free
+ the returned value if it is nonnull and is not BUFFER.
+
+ The PREADLINKAT function specifies how to read links. It operates
+ like POSIX readlinkat()
+ <http://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html>
+ but can assume that its first argument is the same as FD.
+
+ If successful, return the buffer address; otherwise return NULL and
+ set errno. */
+
+char *careadlinkat (int fd, char const *filename,
+ char *buffer, size_t buffer_size,
+ struct allocator const *alloc,
+ ssize_t (*preadlinkat) (int, char const *,
+ char *, size_t));
+
+/* Suitable value for careadlinkat's FD argument. */
+#if HAVE_READLINKAT
+/* AT_FDCWD is declared in <fcntl.h>. */
+#else
+/* Define AT_FDCWD independently, so that the careadlinkat module does
+ not depend on the fcntl-h module. We might as well use the same value
+ as fcntl-h. */
+# ifndef AT_FDCWD
+# define AT_FDCWD (-3041965)
+# endif
+#endif
+
+#endif /* _GL_CAREADLINKAT_H */