procd: service: Support writing pidfiles

Use the "pidfile" attribute of a service to decide whether to write a
pidfile or not.

Files are removed on stop/restart, and correctly created if the config
has changed.

Signed-off-by: Karl Palsson <karlp@etactica.com>

diff --git a/service/instance.c b/service/instance.c
index f2604fef4573c7e8e66fdbb2d8fdc0a35d3c37dd..dccf4b4d231a437a89cbe36c4f070c6f9e95805c 100644 (file)
--- a/service/instance.c
+++ b/service/instance.c
@@ -53,6 +53,7 @@ enum {
        INSTANCE_ATTR_JAIL,
        INSTANCE_ATTR_TRACE,
        INSTANCE_ATTR_SECCOMP,
+       INSTANCE_ATTR_PIDFILE,
        __INSTANCE_ATTR_MAX
 };
 
@@ -75,6 +76,7 @@ static const struct blobmsg_policy instance_attr[__INSTANCE_ATTR_MAX] = {
        [INSTANCE_ATTR_JAIL] = { "jail", BLOBMSG_TYPE_TABLE },
        [INSTANCE_ATTR_TRACE] = { "trace", BLOBMSG_TYPE_BOOL },
        [INSTANCE_ATTR_SECCOMP] = { "seccomp", BLOBMSG_TYPE_STRING },
+       [INSTANCE_ATTR_PIDFILE] = { "pidfile", BLOBMSG_TYPE_STRING },
 };
 
 enum {
@@ -232,6 +234,46 @@ jail_run(struct service_instance *in, char **argv)
        return argc;
 }
 
+static int
+instance_removepid(struct service_instance *in) {
+       if (!in->pidfile)
+               return 0;
+       if (unlink(in->pidfile)) {
+               ERROR("Failed to removed pidfile: %s: %d - %s\n",
+                       in->pidfile, errno, strerror(errno));
+               return 1;
+       }
+       return 0;
+}
+
+static int
+instance_writepid(struct service_instance *in)
+{
+       FILE *_pidfile;
+
+       if (!in->pidfile) {
+               return 0;
+       }
+       _pidfile = fopen(in->pidfile, "w");
+       if (_pidfile == NULL) {
+               ERROR("failed to open pidfile for writing: %s: %d (%s)",
+                       in->pidfile, errno, strerror(errno));
+               return 1;
+       }
+       if (fprintf(_pidfile, "%d\n", in->proc.pid) < 0) {
+               ERROR("failed to write pidfile: %s: %d (%s)",
+                       in->pidfile, errno, strerror(errno));
+               return 2;
+       }
+       if (fclose(_pidfile)) {
+               ERROR("failed to close pidfile: %s: %d (%s)",
+                       in->pidfile, errno, strerror(errno));
+               return 3;
+       }
+
+       return 0;
+}
+
 static void
 instance_run(struct service_instance *in, int _stdout, int _stderr)
 {
@@ -380,8 +422,9 @@ instance_start(struct service_instance *in)
                return;
        }
 
-       DEBUG(2, "Started instance %s::%s\n", in->srv->name, in->name);
+       DEBUG(2, "Started instance %s::%s[%d]\n", in->srv->name, in->name, pid);
        in->proc.pid = pid;
+       instance_writepid(in);
        clock_gettime(CLOCK_MONOTONIC, &in->start);
        uloop_process_add(&in->proc);
 
@@ -498,6 +541,7 @@ instance_stop(struct service_instance *in)
        in->halt = true;
        in->restart = in->respawn = false;
        kill(in->proc.pid, SIGTERM);
+       instance_removepid(in);
 }
 
 static void
@@ -508,6 +552,7 @@ instance_restart(struct service_instance *in)
        in->halt = false;
        in->restart = true;
        kill(in->proc.pid, SIGTERM);
+       instance_removepid(in);
 }
 
 static bool
@@ -540,6 +585,16 @@ instance_config_changed(struct service_instance *in, struct service_instance *in
        if (in->gid != in_new->gid)
                return true;
 
+       if (in->pidfile && in_new->pidfile)
+               if (strcmp(in->pidfile, in_new->pidfile))
+                       return true;
+
+       if (in->pidfile && !in_new->pidfile)
+               return true;
+
+       if (!in->pidfile && in_new->pidfile)
+               return true;
+
        if (!blobmsg_list_equal(&in->limits, &in_new->limits))
                return true;
 
@@ -782,6 +837,13 @@ instance_config_parse(struct service_instance *in)
                else
                        in->seccomp = seccomp;
        }
+
+       if (tb[INSTANCE_ATTR_PIDFILE]) {
+               char *pidfile = blobmsg_get_string(tb[INSTANCE_ATTR_PIDFILE]);
+               if (pidfile)
+                       in->pidfile = pidfile;
+       }
+
        if (!in->trace && tb[INSTANCE_ATTR_JAIL])
                in->has_jail = instance_jail_parse(in, tb[INSTANCE_ATTR_JAIL]);
 
@@ -836,6 +898,7 @@ instance_config_move(struct service_instance *in, struct service_instance *in_sr
        blobmsg_list_move(&in->jail.mount, &in_src->jail.mount);
        in->trigger = in_src->trigger;
        in->command = in_src->command;
+       in->pidfile = in_src->pidfile;
        in->name = in_src->name;
        in->node.avl.key = in_src->node.avl.key;
 
@@ -968,6 +1031,9 @@ void instance_dump(struct blob_buf *b, struct service_instance *in, int verbose)
        if (in->seccomp)
                blobmsg_add_string(b, "seccomp", in->seccomp);
 
+       if (in->pidfile)
+               blobmsg_add_string(b, "pidfile", in->pidfile);
+
        if (in->has_jail) {
                void *r = blobmsg_open_table(b, "jail");
                if (in->jail.name)

diff --git a/service/instance.h b/service/instance.h
index 7490462cfae81a9d4e262839b44eb0b1bc305d8b..1ee04292dcedc2a737c66b247e7b0f3902537088 100644 (file)
--- a/service/instance.h
+++ b/service/instance.h
@@ -56,6 +56,7 @@ struct service_instance {
        bool no_new_privs;
        struct jail jail;
        char *seccomp;
+       char *pidfile;
 
        uint32_t respawn_timeout;
        uint32_t respawn_threshold;