uxc: check for required blockd mounts

When calling `uxc boot` it can happen that some required storage
volumes are not yet mounted. Make sure mountpoints exist for all
required volumes before starting a container using `uxc boot`.
(uxc' init-script will take care of calling `uxc boot` every time
a new block mount is added)

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

diff --git a/uxc.c b/uxc.c
index 210084dcd8fc1855484560f8b164cad4dedd87ac..d1afc4c69b3a594e78757802a09b040a4bfcfbe0 100644 (file)
--- a/uxc.c
+++ b/uxc.c
@@ -65,11 +65,12 @@ enum uxc_cmd {
        CMD_UNKNOWN
 };
 
-#define OPT_ARGS "ab:fp:t:vVw:"
+#define OPT_ARGS "ab:fm:p:t:vVw:"
 static struct option long_options[] = {
        {"autostart",           no_argument,            0,      'a'     },
        {"bundle",              required_argument,      0,      'b'     },
        {"force",               no_argument,            0,      'f'     },
+       {"mounts",              required_argument,      0,      'm'     },
        {"pid-file",            required_argument,      0,      'p'     },
        {"temp-overlay-size",   required_argument,      0,      't'     },
        {"write-overlay-path",  required_argument,      0,      'w'     },
@@ -80,13 +81,19 @@ static struct option long_options[] = {
 
 AVL_TREE(runtime, avl_strcmp, false, NULL);
 static struct blob_buf conf;
+static struct blob_attr *blockinfo;
 static struct ubus_context *ctx;
 
 static int usage(void) {
        printf("syntax: uxc <command> [parameters ...]\n");
        printf("commands:\n");
        printf("\tlist\t\t\t\t\t\tlist all configured containers\n");
-       printf("\tcreate <conf> [--bundle <path>] [--autostart]\tcreate <conf> for OCI bundle at <path>\n");
+       printf("\tcreate <conf>\t\t\t\t\t(re-)create <conf>\n");
+       printf("                [--bundle <path>]\t\t\tOCI bundle at <path>\n");
+       printf("                [--autostart]\t\t\t\tstart on boot\n");
+       printf("                [--temp-overlay-size size]\t\tuse tmpfs overlay with {size}\n");
+       printf("                [--write-overlay-path path]\t\tuse overlay on {path}\n");
+       printf("                [--volumes v1,v2,...,vN]\t\trequire volumes to be available\n");
        printf("\tstart <conf>\t\t\t\t\tstart container <conf>\n");
        printf("\tstate <conf>\t\t\t\t\tget state of container <conf>\n");
        printf("\tkill <conf> [<signal>]\t\t\t\tsend signal to container <conf>\n");
@@ -104,6 +111,7 @@ enum {
        CONF_PIDFILE,
        CONF_TEMP_OVERLAY_SIZE,
        CONF_WRITE_OVERLAY_PATH,
+       CONF_VOLUMES,
        __CONF_MAX,
 };
 
@@ -115,6 +123,7 @@ static const struct blobmsg_policy conf_policy[__CONF_MAX] = {
        [CONF_PIDFILE] = { .name = "pidfile", .type = BLOBMSG_TYPE_STRING },
        [CONF_TEMP_OVERLAY_SIZE] = { .name = "temp-overlay-size", .type = BLOBMSG_TYPE_STRING },
        [CONF_WRITE_OVERLAY_PATH] = { .name = "write-overlay-path", .type = BLOBMSG_TYPE_STRING },
+       [CONF_VOLUMES] = { .name = "volumes", .type = BLOBMSG_TYPE_ARRAY },
 };
 
 static int conf_load(void)
@@ -570,7 +579,7 @@ static int uxc_kill(char *name, int signal)
 }
 
 
-static int uxc_set(char *name, char *path, bool autostart, bool add, char *pidfile, char *_tmprwsize, char *_writepath)
+static int uxc_set(char *name, char *path, bool autostart, bool add, char *pidfile, char *_tmprwsize, char *_writepath, char *requiredmounts)
 {
        static struct blob_buf req;
        struct blob_attr *cur, *tb[__CONF_MAX];
@@ -580,7 +589,8 @@ static int uxc_set(char *name, char *path, bool autostart, bool add, char *pidfi
        char *keeppath = NULL;
        char *tmprwsize = _tmprwsize;
        char *writepath = _writepath;
-
+       char *curvol, *tmp, *mnttok;
+       void *mntarr;
        int f;
        struct stat sb;
 
@@ -647,6 +657,21 @@ static int uxc_set(char *name, char *path, bool autostart, bool add, char *pidfi
        if (writepath)
                blobmsg_add_string(&req, "write-overlay-path", writepath);
 
+       if (!add && tb[CONF_VOLUMES])
+               blobmsg_add_blob(&req, tb[CONF_VOLUMES]);
+
+       if (add && requiredmounts) {
+               mntarr = blobmsg_open_array(&req, "volumes");
+               for (mnttok = requiredmounts; ; mnttok = NULL) {
+                       curvol = strtok_r(mnttok, ",;", &tmp);
+                       if (!curvol)
+                               break;
+
+                       blobmsg_add_string(&req, NULL, curvol);
+               }
+               blobmsg_close_array(&req, mntarr);
+       }
+
        dprintf(f, "%s\n", blobmsg_format_json_indent(req.head, true, 0));
 
        if (!add)
@@ -657,17 +682,88 @@ static int uxc_set(char *name, char *path, bool autostart, bool add, char *pidfi
        return 0;
 }
 
+enum {
+       BLOCK_INFO_DEVICE,
+       BLOCK_INFO_UUID,
+       BLOCK_INFO_TARGET,
+       BLOCK_INFO_TYPE,
+       BLOCK_INFO_MOUNT,
+       __BLOCK_INFO_MAX,
+};
+
+static const struct blobmsg_policy block_info_policy[__BLOCK_INFO_MAX] = {
+       [BLOCK_INFO_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
+       [BLOCK_INFO_UUID] = { .name = "uuid", .type = BLOBMSG_TYPE_STRING },
+       [BLOCK_INFO_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
+       [BLOCK_INFO_TYPE] = { .name = "type", .type = BLOBMSG_TYPE_STRING },
+       [BLOCK_INFO_MOUNT] = { .name = "mount", .type = BLOBMSG_TYPE_STRING },
+};
+
+
+/* check if device 'devname' is mounted according to blockd */
+static int checkblock(char *uuid)
+{
+       struct blob_attr *tb[__BLOCK_INFO_MAX];
+       struct blob_attr *cur;
+       int rem;
+
+       blobmsg_for_each_attr(cur, blockinfo, rem) {
+               blobmsg_parse(block_info_policy, __BLOCK_INFO_MAX, tb, blobmsg_data(cur), blobmsg_len(cur));
+
+               if (!tb[BLOCK_INFO_UUID] || !tb[BLOCK_INFO_MOUNT])
+                       continue;
+
+               if (!strcmp(uuid, blobmsg_get_string(tb[BLOCK_INFO_UUID])))
+                       return 0;
+       }
+
+       return 1;
+}
+
+/* check status of each required volume */
+static int checkvolumes(struct blob_attr *volumes)
+{
+       struct blob_attr *cur;
+       int rem;
+
+       blobmsg_for_each_attr(cur, volumes, rem) {
+               if (checkblock(blobmsg_get_string(cur)))
+                       return 1;
+       }
+
+       return 0;
+}
+
+static void block_cb(struct ubus_request *req, int type, struct blob_attr *msg)
+{
+       blockinfo = blob_memdup(blobmsg_data(msg));
+}
+
 static int uxc_boot(void)
 {
        struct blob_attr *cur, *tb[__CONF_MAX];
        int rem, ret = 0;
        char *name;
+       unsigned int id;
+
+       ret = ubus_lookup_id(ctx, "block", &id);
+       if (ret)
+               return ENOENT;
+
+       ret = ubus_invoke(ctx, id, "info", NULL, block_cb, NULL, 3000);
+       if (ret)
+               return ENXIO;
 
        blobmsg_for_each_attr(cur, blob_data(conf.head), rem) {
                blobmsg_parse(conf_policy, __CONF_MAX, tb, blobmsg_data(cur), blobmsg_len(cur));
                if (!tb[CONF_NAME] || !tb[CONF_PATH] || !tb[CONF_AUTOSTART] || !blobmsg_get_bool(tb[CONF_AUTOSTART]))
                        continue;
 
+               /* make sure all volumes are ready before starting */
+               if (tb[CONF_VOLUMES])
+                       if (checkvolumes(tb[CONF_VOLUMES]))
+                               continue;
+
                name = strdup(blobmsg_get_string(tb[CONF_NAME]));
                ret += uxc_create(name, true);
                free(name);
@@ -763,6 +859,7 @@ int main(int argc, char **argv)
        char *pidfile = NULL;
        char *tmprwsize = NULL;
        char *writepath = NULL;
+       char *requiredmounts = NULL;
        bool autostart = false;
        bool force = false;
        int signal = SIGTERM;
@@ -821,6 +918,10 @@ int main(int argc, char **argv)
                        case 'w':
                                writepath = optarg;
                                break;
+
+                       case 'm':
+                               requiredmounts = optarg;
+                               break;
                }
        }
 
@@ -882,14 +983,14 @@ int main(int argc, char **argv)
                        if (optind != argc - 2)
                                goto usage_out;
 
-                       ret = uxc_set(argv[optind + 1], NULL, true, false, NULL, NULL, NULL);
+                       ret = uxc_set(argv[optind + 1], NULL, true, false, NULL, NULL, NULL, NULL);
                        break;
 
                case CMD_DISABLE:
                        if (optind != argc - 2)
                                goto usage_out;
 
-                       ret = uxc_set(argv[optind + 1], NULL, false, false, NULL, NULL, NULL);
+                       ret = uxc_set(argv[optind + 1], NULL, false, false, NULL, NULL, NULL, NULL);
                        break;
 
                case CMD_DELETE:
@@ -904,7 +1005,7 @@ int main(int argc, char **argv)
                                goto usage_out;
 
                        if (bundle) {
-                               ret = uxc_set(argv[optind + 1], bundle, autostart, true, pidfile, tmprwsize, writepath);
+                               ret = uxc_set(argv[optind + 1], bundle, autostart, true, pidfile, tmprwsize, writepath, requiredmounts);
                                if (ret)
                                        goto runtime_out;