/* Read symbolic links into a buffer without size limitation, relative to fd.
- Copyright (C) 2001, 2003-2004, 2007, 2009-2011 Free Software Foundation,
+ Copyright (C) 2001, 2003-2004, 2007, 2009-2012 Free Software Foundation,
Inc.
This program is free software: you can redistribute it and/or modify
#include "careadlinkat.h"
-#include "allocator.h"
-
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif
-#if ! HAVE_READLINKAT
-/* Ignore FD. Get the symbolic link value of FILENAME and put it into
- BUFFER, with size BUFFER_SIZE. This function acts like readlink
- but has readlinkat's signature. */
+#include "allocator.h"
+
+/* Get the symbolic link value of FILENAME and put it into BUFFER, with
+ size BUFFER_SIZE. This function acts like readlink but has
+ readlinkat's signature. */
ssize_t
careadlinkatcwd (int fd, char const *filename, char *buffer,
size_t buffer_size)
{
- (void) fd;
+ /* FD must be AT_FDCWD here, otherwise the caller is using this
+ function in contexts for which it was not meant for. */
+ if (fd != AT_FDCWD)
+ abort ();
return readlink (filename, buffer, buffer_size);
}
-#endif
-
-/* Forward declaration. We want to #undef malloc before initializing
- this struct, but cannot do so until after all code that uses named
- fields from "allocator.h" has been compiled. */
-static struct allocator const standard_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.
the returned value if it is nonnull and is not BUFFER. A null
ALLOC stands for the standard allocator.
- The PREADLINKAT function specifies how to read links.
+ 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 stack_buf[1024];
if (! alloc)
- alloc = &standard_allocator;
+ alloc = &stdlib_allocator;
if (! buffer_size)
{
if (buf == stack_buf)
{
char *b = (char *) alloc->allocate (link_size);
+ buf_size = link_size;
if (! b)
break;
memcpy (b, buf, link_size);
buf_size *= 2;
else if (buf_size < buf_size_max)
buf_size = buf_size_max;
+ else if (buf_size_max < SIZE_MAX)
+ {
+ errno = ENAMETOOLONG;
+ return NULL;
+ }
else
break;
buf = (char *) alloc->allocate (buf_size);
while (buf);
if (alloc->die)
- alloc->die ();
+ alloc->die (buf_size);
errno = ENOMEM;
return NULL;
}
-
-/* Use the system functions, not the gnulib overrides, because this
- module does not depend on GNU or POSIX semantics. See comments
- above why this must occur here. */
-#undef malloc
-#undef realloc
-
-/* A standard allocator. For now, only careadlinkat needs this, but
- perhaps it should be moved to the allocator module. */
-static struct allocator const standard_allocator =
- { malloc, realloc, free, NULL };