guestfs_cat: Reimplement to avoid protocol limits.

1 files changed, 97 insertions, 0 deletions

diff --git a/src/file.c b/src/file.c
new file mode 100644
index 00000000..b76900d2
--- /dev/null
+++ b/src/file.c
@@ -0,0 +1,97 @@
+/* libguestfs
+ * Copyright (C) 2012 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "full-read.h"
+
+#include "guestfs.h"
+#include "guestfs-internal.h"
+#include "guestfs-internal-actions.h"
+#include "guestfs_protocol.h"
+
+char *
+guestfs__cat (guestfs_h *g, const char *path)
+{
+  int fd = -1;
+  size_t size;
+  char *tmpfile = NULL, *ret = NULL;
+  struct stat statbuf;
+
+  tmpfile = safe_asprintf (g, "%s/cat%d", g->tmpdir, ++g->unique);
+
+  if (guestfs_download (g, path, tmpfile) == -1)
+    goto err;
+
+  fd = open (tmpfile, O_RDONLY|O_CLOEXEC);
+  if (fd == -1) {
+    perrorf (g, "open: %s", tmpfile);
+    goto err;
+  }
+
+  unlink (tmpfile);
+  free (tmpfile);
+  tmpfile = NULL;
+
+  /* Read the whole file into memory. */
+  if (fstat (fd, &statbuf) == -1) {
+    perrorf (g, "stat: %s", tmpfile);
+    goto err;
+  }
+
+  /* Don't use safe_malloc, because we want to return an errno to the caller. */
+  size = statbuf.st_size;
+  ret = malloc (size + 1);
+  if (!ret) {
+    perrorf (g, "malloc: %zu bytes", size + 1);
+    goto err;
+  }
+
+  if (full_read (fd, ret, size) != size) {
+    perrorf (g, "full-read: %s: %zu bytes", tmpfile, size + 1);
+    goto err;
+  }
+
+  ret[size] = '\0';
+
+  if (close (fd) == -1) {
+    perrorf (g, "close: %s", tmpfile);
+    goto err;
+  }
+
+  return ret;
+
+ err:
+  free (ret);
+  if (fd >= 0)
+    close (fd);
+  if (tmpfile) {
+    unlink (tmpfile);
+    free (tmpfile);
+  }
+  return NULL;
+}