From: Rafał Miłecki <[email protected]> As blockd uses uloop calling any script and using waitpid() can easily result in a lock. It's enough for script to use /bin/ubus to cause that.
It's not an option to drop waitpid() as it's important to e.g. call mount scripts with ACTION=remove before unmounting devices. So solving this problem requires using uloop_process. Unfortunately this means: 1. Using callbacks making code slightly more complex 2. Dropping that nice devices_update_cb() With this change however hotplug.d "mount" scripts can safely call "ubus". Signed-off-by: Rafał Miłecki <[email protected]> --- block.c | 4 -- blockd.c | 127 +++++++++++++++++++++++++++++++++++-------------------- 2 files changed, 80 insertions(+), 51 deletions(-) diff --git a/block.c b/block.c index c4ae88a..ac95464 100644 --- a/block.c +++ b/block.c @@ -1218,10 +1218,6 @@ static int main_autofs(int argc, char **argv) blockd_notify(pr->dev, m, pr); } - } else if (!strcmp(argv[2], "available")) { - err = hotplug_call_mount("add", argv[3]); - } else if (!strcmp(argv[2], "unavailable")) { - err = hotplug_call_mount("remove", argv[3]); } else { if (argc < 4) return -EINVAL; diff --git a/blockd.c b/blockd.c index 6e53a13..2fc1bb6 100644 --- a/blockd.c +++ b/blockd.c @@ -25,6 +25,11 @@ #define AUTOFS_TIMEOUT 30 #define AUTOFS_EXPIRE_TIMER (5 * 1000) +struct hotplug_context { + struct uloop_process process; + struct device *device; +}; + struct device { struct vlist_node node; struct blob_attr *msg; @@ -108,15 +113,49 @@ block(char *cmd, char *action, char *device) return ret; } -static void -device_free(struct device *device) +static void hotplug_call_mount(const char *action, struct device *device, + uloop_process_handler cb) { - char *mp; + char * const argv[] = { "hotplug-call", "mount", NULL }; + struct hotplug_context *c = NULL; + pid_t pid; - if (!device->autofs) - return; + if (cb) { + c = calloc(1, sizeof(*c)); + if (!c) + return; + } + + pid = fork(); + switch (pid) { + case -1: + ULOG_ERR("fork() failed\n"); + break; + case 0: + uloop_end(); + + setenv("ACTION", action, 1); + setenv("DEVICE", device->name, 1); + + execv("/sbin/hotplug-call", argv); + exit(-1); + break; + default: + if (c) { + c->process.pid = pid; + c->process.cb = cb; + c->device = device; + uloop_process_add(&c->process); + } + break; + } +} - block("autofs", "unavailable", device->name); +static void device_mount_remove_hotplug_cb(struct uloop_process *p, int stat) +{ + struct hotplug_context *c = container_of(p, struct hotplug_context, process); + struct device *device = c->device; + char *mp; if (device->target) unlink(device->target); @@ -126,17 +165,21 @@ device_free(struct device *device) block("autofs", "remove", device->name); free(mp); } + + free(device); + free(c); } -static void -device_add(struct device *device) +static void device_mount_remove(struct device *device) +{ + hotplug_call_mount("remove", device, device_mount_remove_hotplug_cb); +} + +static void device_mount_add(struct device *device) { struct stat st; char path[64]; - if (!device->autofs) - return; - snprintf(path, sizeof(path), "/tmp/run/blockd/%s", device->name); if (!lstat(device->target, &st)) { if (S_ISLNK(st.st_mode)) @@ -147,7 +190,7 @@ device_add(struct device *device) if (symlink(path, device->target)) ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device->target, path, errno); else - block("autofs", "available", device->name); + hotplug_call_mount("add", device, NULL); } static int @@ -177,36 +220,13 @@ device_move(struct device *device_o, struct device *device_n) return 0; } -static void -devices_update_cb(struct vlist_tree *tree, struct vlist_node *node_new, - struct vlist_node *node_old) +static void vlist_nop_update(struct vlist_tree *tree, + struct vlist_node *node_new, + struct vlist_node *node_old) { - struct device *device_o = NULL, *device_n = NULL; - - if (node_old) - device_o = container_of(node_old, struct device, node); - - if (node_new) - device_n = container_of(node_new, struct device, node); - - if (device_o && device_n) { - if (device_move(device_o, device_n)) { - device_free(device_o); - device_add(device_n); - if (!device_n->autofs) - block("mount", NULL, NULL); - } - } else if (device_n) { - device_add(device_n); - } else { - device_free(device_o); - } - - if (device_o) - free(device_o); } -VLIST_TREE(devices, avl_strcmp, devices_update_cb, false, false); +VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false); static int block_hotplug(struct ubus_context *ctx, struct ubus_object *obj, @@ -246,22 +266,35 @@ block_hotplug(struct ubus_context *ctx, struct ubus_object *obj, if (data[MOUNT_REMOVE]) { vlist_delete(&devices, &device->node); - } else { - if (data[MOUNT_AUTOFS]) - device->autofs = blobmsg_get_u32(data[MOUNT_AUTOFS]); - else - device->autofs = 0; - if (data[MOUNT_ANON]) - device->anon = blobmsg_get_u32(data[MOUNT_ANON]); + + if (device->autofs) + device_mount_remove(device); else - device->anon = 0; + free(device); + } else { + struct device *old = vlist_find(&devices, devname, device, node); + + device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0; + device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0; device->msg = _msg; memcpy(_msg, msg, blob_raw_len(msg)); device->name = _name; strcpy(_name, devname); device->target = __target; strcpy(__target, target); + vlist_add(&devices, &device->node, device->name); + + if (old && !device_move(old, device)) { + if (device->autofs) { + device_mount_remove(old); + device_mount_add(device); + } else { + block("mount", NULL, NULL); + } + } else if (device->autofs) { + device_mount_add(device); + } } return 0; -- 2.26.1 _______________________________________________ openwrt-devel mailing list [email protected] https://lists.openwrt.org/mailman/listinfo/openwrt-devel
