Check error returns from posix_fallocate (RHBZ#579664).

posix_fallocate has a non-standard way to return error indications.
Thus all our calls to posix_fallocate were effectively unchecked.  For
example:

  $ guestfish alloc test.img 1P
  $ echo $?
  0
  $ ll test.img
  -rw-rw-r--. 1 rjones rjones 0 2010-04-06 11:02 test.img
  $ rm test.img

With this change, errors are detected and reported properly:

  $ ./fish/guestfish alloc test.img 1P
  fallocate: File too large

This is a fix for:
https://bugzilla.redhat.com/show_bug.cgi?id=579664

1 files changed, 4 insertions, 4 deletions

diff --git a/daemon/fallocate.c b/daemon/fallocate.c
index 7f17f8b8..49474307 100644
--- a/daemon/fallocate.c
+++ b/daemon/fallocate.c
@@ -23,6 +23,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <errno.h>
 
 #include "daemon.h"
 #include "actions.h"
@@ -41,10 +42,9 @@ do_fallocate (const char *path, int len)
   }
 
 #ifdef HAVE_POSIX_FALLOCATE
-  int r;
-
-  r = posix_fallocate (fd, 0, len);
-  if (r == -1) {
+  int err = posix_fallocate (fd, 0, len);
+  if (err != 0) {
+    errno = err;
     reply_with_perror ("%s", path);
     close (fd);
     return -1;