10:13 a.m.
From: "Richard W.M. Jones" <rjones(a)redhat.com>
---
fuse/guestmount.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
fuse/guestmount.pod | 8 +++++++-
2 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/fuse/guestmount.c b/fuse/guestmount.c
index 0c2e2dc..fd31726 100644
--- a/fuse/guestmount.c
+++ b/fuse/guestmount.c
@@ -42,6 +42,8 @@
#include "guestmount.h"
#include "options.h"
+static int write_pid_file (const char *pid_file, pid_t pid);
+
#ifndef HAVE_FUSE_OPT_ADD_OPT_ESCAPED
/* Copied from lib/fuse_opt.c and modified.
* Copyright (C) 2001-2007 Miklos Szeredi <miklos(a)szeredi.hu>
@@ -119,6 +121,7 @@ usage (int status)
" -m|--mount dev[:mnt[:opts]] Mount dev on mnt (if omitted,
/)\n"
" -n|--no-sync Don't autosync\n"
" -o|--option opt Pass extra option to FUSE\n"
+ " --pid-file filename Write PID to filename\n"
" -r|--ro Mount read-only\n"
" --selinux Enable SELinux support\n"
" -v|--verbose Verbose messages\n"
@@ -161,6 +164,7 @@ main (int argc, char *argv[])
{ "mount", 1, 0, 'm' },
{ "no-sync", 0, 0, 'n' },
{ "option", 1, 0, 'o' },
+ { "pid-file", 1, 0, 0 },
{ "ro", 0, 0, 'r' },
{ "rw", 0, 0, 'w' },
{ "selinux", 0, 0, 0 },
@@ -184,6 +188,7 @@ main (int argc, char *argv[])
int dir_cache_timeout = -1;
int do_fork = 1;
char *fuse_options = NULL;
+ char *pid_file = NULL;
struct guestfs_mount_local_argv optargs;
@@ -227,6 +232,8 @@ main (int argc, char *argv[])
echo_keys = 1;
} else if (STREQ (long_options[option_index].name, "live")) {
live = 1;
+ } else if (STREQ (long_options[option_index].name, "pid-file")) {
+ pid_file = optarg;
} else {
fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
program_name, long_options[option_index].name, option_index);
@@ -406,8 +413,12 @@ main (int argc, char *argv[])
exit (EXIT_FAILURE);
}
- if (pid != 0) /* parent */
+ if (pid != 0) { /* parent */
+ if (write_pid_file (pid_file, pid) == -1)
+ _exit (EXIT_FAILURE);
+
_exit (EXIT_SUCCESS);
+ }
/* Emulate what old fuse_daemonize used to do. */
if (setsid () == -1) {
@@ -426,6 +437,11 @@ main (int argc, char *argv[])
close (fd);
}
}
+ else {
+ /* not forking, write PID file anyway */
+ if (write_pid_file (pid_file, getpid ()) == -1)
+ exit (EXIT_FAILURE);
+ }
/* Main loop. */
r = guestfs_mount_local_run (g);
@@ -435,5 +451,33 @@ main (int argc, char *argv[])
r = -1;
guestfs_close (g);
+ /* Don't delete PID file until the cleanup has been completed. */
+ if (pid_file)
+ unlink (pid_file);
+
exit (r == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}
+
+static int
+write_pid_file (const char *pid_file, pid_t pid)
+{
+ FILE *fp;
+
+ if (pid_file == NULL)
+ return 0;
+
+ fp = fopen (pid_file, "w");
+ if (fp == NULL) {
+ error:
+ perror (pid_file);
+ return -1;
+ }
+
+ if (fprintf (fp, "%d\n", pid) == -1)
+ goto error;
+
+ if (fclose (fp) == -1)
+ goto error;
+
+ return 0;
+}
diff --git a/fuse/guestmount.pod b/fuse/guestmount.pod
index d459045..fdcf133 100644
--- a/fuse/guestmount.pod
+++ b/fuse/guestmount.pod
@@ -120,7 +120,9 @@ condition:
fusermount -u /mnt
# immediately try to use 'disk.img' <-- UNSAFE
-The solution is to spin waiting for the guestmount process to exit.
+The solution is to use the I<--pid-file> option to write the
+guestmount PID to a file, then after fusermount spin waiting for this
+PID to exit.
Note that if you use the C<guestfs_mount_local> API directly (see
L<guestfs(3)/MOUNT LOCAL>) then it is much easier to write a safe,
@@ -282,6 +284,10 @@ to the chosen values.
=back
+=item B<--pid-file filename>
+
+Write the PID of the guestmount worker process to C<filename>.
+
=item B<-r>
=item B<--ro>
--
1.7.10.4