From: Richard Jones <rich@koneko.home.annexia.org>
Date: Sun, 21 Mar 2010 19:13:43 +0000 (+0000)
Subject: Mac OS X: provide alternate implementation of posix_fallocate.
X-Git-Tag: 1.0.87~12
X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=commitdiff_plain;h=5ebf3a39340696fea0582a58074d22d11247a6e7

Mac OS X: provide alternate implementation of posix_fallocate.
---

diff --git a/configure.ac b/configure.ac
index b13eaf9..cfad704 100644
--- a/configure.ac
+++ b/configure.ac
@@ -134,6 +134,9 @@ AC_DEFINE_UNQUOTED([host_cpu],["$host_cpu"],[Host architecture.])
 dnl Headers.
 AC_CHECK_HEADERS([errno.h sys/types.h sys/un.h sys/wait.h sys/socket.h endian.h byteswap.h])
 
+dnl Functions.
+AC_CHECK_FUNCS([posix_fallocate])
+
 dnl Build the daemon?
 AC_MSG_CHECKING([if we should build the daemon])
 AC_ARG_ENABLE([daemon],
diff --git a/fish/alloc.c b/fish/alloc.c
index ad2dccc..28c990f 100644
--- a/fish/alloc.c
+++ b/fish/alloc.c
@@ -54,12 +54,31 @@ do_alloc (const char *cmd, int argc, char *argv[])
     return -1;
   }
 
+#ifdef HAVE_POSIX_FALLOCATE
   if (posix_fallocate (fd, 0, size) == -1) {
     perror ("fallocate");
     close (fd);
     unlink (argv[0]);
     return -1;
   }
+#else
+  /* Slow emulation of posix_fallocate on platforms which don't have it. */
+  char buffer[BUFSIZ];
+  memset (buffer, 0, sizeof buffer);
+
+  size_t remaining = size;
+  while (remaining > 0) {
+    size_t n = remaining > sizeof buffer ? sizeof buffer : remaining;
+    ssize_t r = write (fd, buffer, n);
+    if (r == -1) {
+      perror ("write");
+      close (fd);
+      unlink (argv[0]);
+      return -1;
+    }
+    remaining -= r;
+  }
+#endif
 
   if (close (fd) == -1) {
     perror (argv[0]);