[PATCH RFC rpcd] rc: new ubus object for handling /etc/init.d/ scripts
Rafał Miłecki
zajec5 at gmail.com
Tue Jun 23 01:06:10 EDT 2020
From: Rafał Miłecki <rafal at milecki.pl>
This commit adds "rc" ubus object with "exec" method that allows calling
/etc/init.d/ scripts. It's useful for all kind of UIs (e.g. LuCI) and
custom apps.
The next step should be "list" method support listing add init scripts.
Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
---
I didn't implement custom timeout for waiting for init.d script yet. Two
reasons:
1. ubus call will eventually timeout on its own
2. it'd be nice to have some uloop_process helper for that
---
CMakeLists.txt | 2 +-
include/rpcd/rc.h | 7 +++
main.c | 6 +-
rc.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 152 insertions(+), 3 deletions(-)
create mode 100644 include/rpcd/rc.h
create mode 100644 rc.c
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3bfc286..26e011e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -38,7 +38,7 @@ INCLUDE_DIRECTORIES(${ubus_include_dir})
FIND_PATH(ubox_include_dir libubox/blobmsg_json.h)
INCLUDE_DIRECTORIES(${ubox_include_dir})
-ADD_EXECUTABLE(rpcd main.c exec.c session.c uci.c plugin.c)
+ADD_EXECUTABLE(rpcd main.c exec.c session.c uci.c rc.c plugin.c)
TARGET_LINK_LIBRARIES(rpcd ${ubox} ${ubus} ${uci} ${blobmsg_json} ${json} ${crypt} dl)
SET(PLUGINS "")
diff --git a/include/rpcd/rc.h b/include/rpcd/rc.h
new file mode 100644
index 0000000..ca00f56
--- /dev/null
+++ b/include/rpcd/rc.h
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: ISC OR MIT
+#ifndef __RPCD_RC_H
+#define __RPCD_RC_H
+
+int rpc_rc_api_init(struct ubus_context *ctx);
+
+#endif
diff --git a/main.c b/main.c
index 9a177cf..d77a814 100644
--- a/main.c
+++ b/main.c
@@ -25,10 +25,11 @@
#include <signal.h>
#include <sys/stat.h>
+#include <rpcd/exec.h>
+#include <rpcd/plugin.h>
+#include <rpcd/rc.h>
#include <rpcd/session.h>
#include <rpcd/uci.h>
-#include <rpcd/plugin.h>
-#include <rpcd/exec.h>
static struct ubus_context *ctx;
static bool respawn = false;
@@ -113,6 +114,7 @@ int main(int argc, char **argv)
rpc_session_api_init(ctx);
rpc_uci_api_init(ctx);
+ rpc_rc_api_init(ctx);
rpc_plugin_api_init(ctx);
hangup = getenv("RPC_HANGUP");
diff --git a/rc.c b/rc.c
new file mode 100644
index 0000000..a354332
--- /dev/null
+++ b/rc.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: ISC OR MIT
+/*
+ * rpcd - UBUS RPC server
+ *
+ * Copyright (C) 2020 Rafał Miłecki <rafal at milecki.pl>
+ */
+
+#include <fcntl.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include <libubox/blobmsg.h>
+#include <libubox/uloop.h>
+#include <libubus.h>
+
+#include <rpcd/rc.h>
+
+enum {
+ RC_EXEC_NAME,
+ RC_EXEC_ACTION,
+ __RC_EXEC_MAX
+};
+
+static const struct blobmsg_policy rc_exec_policy[] = {
+ [RC_EXEC_NAME] = { "name", BLOBMSG_TYPE_STRING },
+ [RC_EXEC_ACTION] = { "action", BLOBMSG_TYPE_STRING },
+};
+
+struct rc_exec_context {
+ struct uloop_process process;
+ struct ubus_context *ctx;
+ struct ubus_request_data req;
+};
+
+static void rc_exec_cb(struct uloop_process *p, int stat)
+{
+ struct rc_exec_context *c = container_of(p, struct rc_exec_context, process);
+
+ ubus_complete_deferred_request(c->ctx, &c->req, UBUS_STATUS_OK);
+
+ free(c);
+}
+
+static int rc_exec(struct ubus_context *ctx, struct ubus_object *obj,
+ struct ubus_request_data *req, const char *method,
+ struct blob_attr *msg)
+{
+ struct blob_attr *tb[__RC_EXEC_MAX];
+ struct rc_exec_context *c;
+ struct stat s;
+ const char *action;
+ const char *name;
+ char script[PATH_MAX];
+ pid_t pid;
+ const char *chr;
+ int fd;
+
+ blobmsg_parse(rc_exec_policy, __RC_EXEC_MAX, tb, blobmsg_data(msg), blobmsg_data_len(msg));
+
+ if (!tb[RC_EXEC_NAME] || !tb[RC_EXEC_ACTION])
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ name = blobmsg_get_string(tb[RC_EXEC_NAME]);
+
+ /* Validate script name */
+ for (chr = name; (chr = strchr(chr, '.')); chr++) {
+ if (*(chr + 1) == '.')
+ return UBUS_STATUS_INVALID_ARGUMENT;
+ }
+ if (strchr(name, '/'))
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ /* Validate script privileges */
+ snprintf(script, sizeof(script), "/etc/init.d/%s", name);
+ if (stat(script, &s))
+ return UBUS_STATUS_NOT_FOUND;
+ if (s.st_uid != 0 || s.st_gid != 0 || !(s.st_mode & S_IXUSR) || (s.st_mode & (S_IWGRP | S_IWOTH)))
+ return UBUS_STATUS_PERMISSION_DENIED;
+
+ action = blobmsg_get_string(tb[RC_EXEC_ACTION]);
+ if (strcmp(action, "disable") &&
+ strcmp(action, "enable") &&
+ strcmp(action, "stop") &&
+ strcmp(action, "start") &&
+ strcmp(action, "restart") &&
+ strcmp(action, "reload"))
+ return UBUS_STATUS_INVALID_ARGUMENT;
+
+ c = calloc(1, sizeof(*c));
+ if (!c)
+ return UBUS_STATUS_UNKNOWN_ERROR;
+
+ pid = fork();
+ switch (pid) {
+ case -1:
+ free(c);
+ return UBUS_STATUS_UNKNOWN_ERROR;
+ case 0:
+ /* Set stdin, stdout & stderr to /dev/null */
+ fd = open("/dev/null", O_RDWR);
+ if (fd >= 0) {
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ close(fd);
+ }
+
+ execl(script, script, action, NULL);
+ exit(errno);
+ default:
+ c->ctx = ctx;
+ c->process.pid = pid;
+ c->process.cb = rc_exec_cb;
+ uloop_process_add(&c->process);
+
+ ubus_defer_request(ctx, req, &c->req);
+
+ return 0; /* Deferred */
+ }
+}
+
+int rpc_rc_api_init(struct ubus_context *ctx)
+{
+ static const struct ubus_method rc_methods[] = {
+ UBUS_METHOD("exec", rc_exec, rc_exec_policy),
+ };
+
+ static struct ubus_object_type rc_type =
+ UBUS_OBJECT_TYPE("rc", rc_methods);
+
+ static struct ubus_object obj = {
+ .name = "rc",
+ .type = &rc_type,
+ .methods = rc_methods,
+ .n_methods = ARRAY_SIZE(rc_methods),
+ };
+
+ return ubus_add_object(ctx, &obj);
+}
--
2.26.1
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