[Libguestfs] [PATCH 2/3] fish: In edit command, upload to a new file.
Richard W.M. Jones
rjones at redhat.com
Fri Feb 10 10:39:17 UTC 2012
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
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>From 8a1762d865cca34f7625985ed67d060367544057 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Fri, 10 Feb 2012 10:12:45 +0000
Subject: [PATCH 2/3] fish: In edit command, upload to a new file.
If the upload fails, this means we don't leave a partially
written file.
Also add a test for the edit command.
---
fish/Makefile.am | 1 +
fish/edit.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++--
fish/fish.c | 3 ++
fish/test-edit.sh | 51 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 110 insertions(+), 3 deletions(-)
create mode 100755 fish/test-edit.sh
diff --git a/fish/Makefile.am b/fish/Makefile.am
index 8a6f88b..badb04d 100644
--- a/fish/Makefile.am
+++ b/fish/Makefile.am
@@ -247,6 +247,7 @@ TESTS = \
if ENABLE_APPLIANCE
TESTS += \
test-copy.sh \
+ test-edit.sh \
test-find0.sh \
test-read_file.sh \
test-remote.sh \
diff --git a/fish/edit.c b/fish/edit.c
index e0204b0..908a3a3 100644
--- a/fish/edit.c
+++ b/fish/edit.c
@@ -26,9 +26,12 @@
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <assert.h>
#include "fish.h"
+static char *generate_random_name (const char *filename);
+
/* guestfish edit command, suggested by J?n Ondrej, implemented by RWMJ */
int
@@ -37,7 +40,7 @@ run_edit (const char *cmd, size_t argc, char *argv[])
TMP_TEMPLATE_ON_STACK (filename);
char buf[256];
const char *editor;
- char *remotefilename;
+ char *remotefilename, *newname;
struct stat oldstat, newstat;
int r, fd;
@@ -111,14 +114,29 @@ run_edit (const char *cmd, size_t argc, char *argv[])
return 0;
}
- /* Write new content. */
- if (guestfs_upload (g, filename, remotefilename) == -1)
+ /* Upload to a new file in the same directory, so if it fails we
+ * don't end up with a partially written file. Give the new file
+ * a completely random name so we have only a tiny chance of
+ * overwriting some existing file.
+ */
+ newname = generate_random_name (remotefilename);
+ if (!newname)
goto error2;
+ /* Write new content. */
+ if (guestfs_upload (g, filename, newname) == -1)
+ goto error3;
+
+ if (guestfs_mv (g, newname, remotefilename) == -1)
+ goto error3;
+
+ free (newname);
unlink (filename);
free (remotefilename);
return 0;
+ error3:
+ free (newname);
error2:
unlink (filename);
error1:
@@ -126,3 +144,37 @@ run_edit (const char *cmd, size_t argc, char *argv[])
error0:
return -1;
}
+
+static char
+random_char (void)
+{
+ char c[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+ return c[random () % (sizeof c - 1)];
+}
+
+static char *
+generate_random_name (const char *filename)
+{
+ char *ret, *p;
+ size_t i;
+
+ ret = malloc (strlen (filename) + 16);
+ if (!ret) {
+ perror ("malloc");
+ return NULL;
+ }
+ strcpy (ret, filename);
+
+ p = strrchr (ret, '/');
+ assert (p);
+ p++;
+
+ /* Because of "+ 16" above, there should be enough space in the
+ * output buffer to write 8 random characters here.
+ */
+ for (i = 0; i < 8; ++i)
+ *p++ = random_char ();
+ *p++ = '\0';
+
+ return ret; /* caller will free */
+}
diff --git a/fish/fish.c b/fish/fish.c
index e388832..575fe99 100644
--- a/fish/fish.c
+++ b/fish/fish.c
@@ -163,6 +163,9 @@ main (int argc, char *argv[])
bindtextdomain (PACKAGE, LOCALEBASEDIR);
textdomain (PACKAGE);
+ /* We use random(3) in edit.c. */
+ srandom (time (NULL));
+
parse_config ();
enum { HELP_OPTION = CHAR_MAX + 1 };
diff --git a/fish/test-edit.sh b/fish/test-edit.sh
new file mode 100755
index 0000000..ff38d1c
--- /dev/null
+++ b/fish/test-edit.sh
@@ -0,0 +1,51 @@
+#!/bin/bash -
+# libguestfs
+# Copyright (C) 2012 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# Test guestfish edit command.
+
+# This test fails on some versions of mock which lack /dev/fd
+# directory. Skip this test in that case.
+
+test -d /dev/fd || {
+ echo "$0: Skipping this test because /dev/fd is missing."
+ exit 0
+}
+
+set -e
+
+rm -f test1.img
+
+# The command will be 'echo ... >>/tmp/tmpfile'
+export EDITOR="echo second line of text >>"
+
+output=$(
+../fish/guestfish -N fs -m /dev/sda1 <<EOF
+write /file.txt "this is a test\n"
+edit /file.txt
+cat /file.txt
+EOF
+)
+
+if [ "$output" != "this is a test
+second line of text" ]; then
+ echo "$0: error: output of guestfish after edit command did not match expected output"
+ echo "$output"
+ exit 1
+fi
+
+rm -f test1.img
--
1.7.9
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