lxc-start: add option -p, --pidfile=FILE

Add option to create a pidfile for lxc-start. This is helpful for
init scripts and process monitors when running as daemon.

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/doc/lxc-start.sgml.in b/doc/lxc-start.sgml.in
index af79bbc6e248d0cd696b7aafbab6fddf31a8f92e..e4b90079b98992dd9ae956da0c9d5a48071089ca 100644 (file)
--- a/doc/lxc-start.sgml.in
+++ b/doc/lxc-start.sgml.in
@@ -53,6 +53,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       <arg choice="opt">-f <replaceable>config_file</replaceable></arg>
       <arg choice="opt">-c <replaceable>console_file</replaceable></arg>
       <arg choice="opt">-d</arg>
+      <arg choice="opt">-p <replaceable>pid_file</replaceable></arg>
       <arg choice="opt">-s KEY=VAL</arg>
       <arg choice="opt">-C</arg>
       <arg choice="opt">command</arg>
@@ -107,6 +108,17 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
        </listitem>
       </varlistentry>
 
+      <varlistentry>
+       <term>
+         <option>-p, --pidfile <replaceable>pid_file</replaceable></option>
+       </term>
+       <listitem>
+         <para>
+           Create a file with the process id.
+         </para>
+       </listitem>
+      </varlistentry>
+
       <varlistentry>
        <term>
          <option>-f, --rcfile <replaceable>config_file</replaceable></option>

diff --git a/src/lxc/arguments.h b/src/lxc/arguments.h
index 3c9d28fd7b140e64b32eb1bc6357788491b31095..188c4606bb4fb67ac1978979759262705040149c 100644 (file)
--- a/src/lxc/arguments.h
+++ b/src/lxc/arguments.h
@@ -45,6 +45,7 @@ struct lxc_arguments {
        int daemonize;
        const char *rcfile;
        const char *console;
+       const char *pidfile;
 
        /* for lxc-checkpoint/restart */
        const char *statefile;

diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index 81a5774c4672df89a8f48c323e364d91d33e9806..ca1cc2a1939e8ad16e4ec22b5323bfe5fe250f45 100644 (file)
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -62,6 +62,7 @@ static int my_parser(struct lxc_arguments* args, int c, char* arg)
        case 'f': args->rcfile = arg; break;
        case 'C': args->close_all_fds = 1; break;
        case 's': return lxc_config_define_add(&defines, arg);
+       case 'p': args->pidfile = arg; break;
        }
        return 0;
 }
@@ -72,6 +73,7 @@ static const struct option my_longopts[] = {
        {"define", required_argument, 0, 's'},
        {"console", required_argument, 0, 'c'},
        {"close-all-fds", no_argument, 0, 'C'},
+       {"pidfile", required_argument, 0, 'p'},
        LXC_COMMON_OPTIONS
 };
 
@@ -85,6 +87,7 @@ lxc-start start COMMAND in specified container NAME\n\
 Options :\n\
   -n, --name=NAME      NAME for name of the container\n\
   -d, --daemon         daemonize the container\n\
+  -p, --pidfile=FILE   Create a file with the process id\n\
   -f, --rcfile=FILE    Load configuration file FILE\n\
   -c, --console=FILE   Set the file output for the container console\n\
   -C, --close-all-fds  If any fds are inherited, close them\n\
@@ -95,6 +98,7 @@ Options :\n\
        .parser    = my_parser,
        .checker   = NULL,
        .daemonize = 0,
+       .pidfile = NULL,
 };
 
 int main(int argc, char *argv[])
@@ -107,6 +111,7 @@ int main(int argc, char *argv[])
                "/sbin/init",
                '\0',
        };
+       FILE *pid_fp = NULL;
 
        lxc_list_init(&defines);
 
@@ -199,6 +204,14 @@ int main(int argc, char *argv[])
                free(console);
        }
 
+       if (my_args.pidfile != NULL) {
+               pid_fp = fopen(my_args.pidfile, "w");
+               if (pid_fp == NULL) {
+                       SYSERROR("failed to create '%s'", my_args.name);
+                       return err;
+               }
+       }
+
        if (my_args.daemonize) {
                /* do an early check for needed privs, since otherwise the
                 * user won't see the error */
@@ -214,6 +227,14 @@ int main(int argc, char *argv[])
                }
        }
 
+       if (pid_fp != NULL) {
+               if (fprintf(pid_fp, "%d\n", getpid()) < 0) {
+                       SYSERROR("failed to write '%s'", my_args.pidfile);
+                       return err;
+               }
+               fclose(pid_fp);
+       }
+
        if (my_args.close_all_fds)
                conf->close_all_fds = 1;
 
@@ -230,6 +251,9 @@ int main(int argc, char *argv[])
                err = -1;
        }
 
+       if (my_args.pidfile)
+               unlink(my_args.pidfile);
+
        return err;
 }