1 files changed, 49 insertions, 4 deletions
diff --git a/shadow/fgetspent.c b/shadow/fgetspent.c
index 6fe813b520..bd54c7e595 100644
--- a/shadow/fgetspent.c
+++ b/shadow/fgetspent.c
@@ -16,18 +16,63 @@
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
 
+#include <errno.h>
+#include <libc-lock.h>
 #include <shadow.h>
-#include <stdio.h>
+#include <stdlib.h>
 
 
+/* A reasonable size for a buffer to start with.  */
+#define BUFLEN_SPWD 1024
+
+/* We need to protect the dynamic buffer handling.  */
+__libc_lock_define_initialized (static, lock);
+
 /* Read one shadow entry from the given stream.  */
 struct spwd *
 fgetspent (FILE *stream)
 {
-  static char buffer[BUFSIZ];
+  static char *buffer;
+  static size_t buffer_size;
   static struct spwd resbuf;
   struct spwd *result;
+  int save;
+
+  /* Get lock.  */
+  __libc_lock_lock (lock);
+
+  /* Allocate buffer if not yet available.  */
+  if (buffer == NULL)
+    {
+      buffer_size = BUFLEN_SPWD;
+      buffer = malloc (buffer_size);
+    }
+
+  while (buffer != NULL
+	 && __fgetspent_r (stream, &resbuf, buffer, buffer_size, &result) != 0
+	 && errno == ERANGE)
+    {
+      char *new_buf;
+      buffer_size += BUFLEN_SPWD;
+      new_buf = realloc (buffer, buffer_size);
+      if (new_buf == NULL)
+	{
+	  /* We are out of memory.  Free the current buffer so that the
+	     process gets a chance for a normal termination.  */
+	  save = errno;
+	  free (buffer);
+	  __set_errno (save);
+	}
+      buffer = new_buf;
+    }
+
+  if (buffer == NULL)
+    result = NULL;
+
+  /* Release lock.  Preserve error value.  */
+  save = errno;
+  __libc_lock_unlock (lock);
+  __set_errno (save);
 
-  return __fgetspent_r (stream, &resbuf, buffer, sizeof buffer, &result)
-    ? NULL : result;
+  return result;
 }