X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fcareadlinkat.c;h=751578b9a58fc6f46894cbbef3237d716f1c347b;hb=07809063056aef043ba738ab8229042f1ffc9659;hp=0b54b1dfd76a6e3cc747b2fcbda3b15ecec71160;hpb=7a6955f7b5a90dbd30cb88217406c49c23ead9d1;p=gnulib.git

diff --git a/lib/careadlinkat.c b/lib/careadlinkat.c
index 0b54b1dfd..751578b9a 100644
--- a/lib/careadlinkat.c
+++ b/lib/careadlinkat.c
@@ -22,8 +22,6 @@
 
 #include "careadlinkat.h"
 
-#include "allocator.h"
-
 #include <errno.h>
 #include <limits.h>
 #include <stdlib.h>
@@ -39,23 +37,21 @@
 # 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.
@@ -71,7 +67,10 @@ static struct allocator const standard_allocator;
    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.  */
@@ -89,7 +88,7 @@ careadlinkat (int fd, char const *filename,
   char stack_buf[1024];
 
   if (! alloc)
-    alloc = &standard_allocator;
+    alloc = &stdlib_allocator;
 
   if (! buffer_size)
     {
@@ -134,6 +133,7 @@ careadlinkat (int fd, char const *filename,
           if (buf == stack_buf)
             {
               char *b = (char *) alloc->allocate (link_size);
+              buf_size = link_size;
               if (! b)
                 break;
               memcpy (b, buf, link_size);
@@ -157,6 +157,11 @@ careadlinkat (int fd, char const *filename,
         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);
@@ -164,18 +169,7 @@ careadlinkat (int fd, char const *filename,
   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 };