Getting error while wrting code for UCI in openwrt - c

Question

I was trying to write code for UCI which can read the users UCI config file but the code is throwing following error
make[4]: Entering directory '/home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld'
ccache_cc -Os -pipe -g3 -fno-caller-saves -fno-plt -fhonour-copts -Wno-error=unused-but-set-variable -Wno-error=unused-result -fmacro-prefix-map=/home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld=helloworld -Wformat -Werror=format-security -fstack-protector -D_FORTIFY_SOURCE=1 -Wl,-z,now -Wl,-z,relro -Wl,--build-id -I/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/usr/include -I/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/include/fortify -I/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/include -c helloworld.c
ccache_cc -L/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/usr/lib -L/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib -znow -zrelro -lubus -lubox helloworld.o -o helloworld
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib/gcc/x86_64-openwrt-linux-musl/11.2.0/../../../../x86_64-openwrt-linux-musl/bin/ld: helloworld.o: in function `config__':
/home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld/helloworld.c:47: undefined reference to `uci_alloc_context'
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib/gcc/x86_64-openwrt-linux-musl/11.2.0/../../../../x86_64-openwrt-linux-musl/bin/ld: /home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld/helloworld.c:49: undefined reference to `uci_load'
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib/gcc/x86_64-openwrt-linux-musl/11.2.0/../../../../x86_64-openwrt-linux-musl/bin/ld: helloworld.o: in function `uci_lookup_section':
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/target-x86_64_musl/usr/include/uci.h:654: undefined reference to `uci_lookup_next'
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib/gcc/x86_64-openwrt-linux-musl/11.2.0/../../../../x86_64-openwrt-linux-musl/bin/ld: /home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/target-x86_64_musl/usr/include/uci.h:654: undefined reference to `uci_lookup_next'
/home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/toolchain-x86_64_gcc-11.2.0_musl/lib/gcc/x86_64-openwrt-linux-musl/11.2.0/../../../../x86_64-openwrt-linux-musl/bin/ld: helloworld.o: in function `config__':
/home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld/helloworld.c:55: undefined reference to `uci_free_context'
collect2: error: ld returned 1 exit status
make[4]: *** [Makefile:3: helloworld] Error 1
make[4]: Leaving directory '/home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld'
make[3]: *** [Makefile:94: /home/krishanudev/iowrtFinal/iopsyswrt/build_dir/target-x86_64_musl/helloworld/.built] Error 2
make[3]: Leaving directory '/home/krishanudev/iowrtFinal/iopsyswrt/package/helloworld'
time: package/helloworld/compile#0.70#0.09#0.79
ERROR: package/helloworld failed to build.
make[2]: *** [package/Makefile:116: package/helloworld/compile] Error 1
make[2]: Leaving directory '/home/krishanudev/iowrtFinal/iopsyswrt'
make[1]: *** [package/Makefile:110: /home/krishanudev/iowrtFinal/iopsyswrt/staging_dir/target-x86_64_musl/stamp/.package_compile] Error 2
make[1]: Leaving directory '/home/krishanudev/iowrtFinal/iopsyswrt'
make: *** [/home/krishanudev/iowrtFinal/iopsyswrt/include/toplevel.mk:237: world] Error 2
The output expected from the below code is nothing but just echoing the ubus calls value.
How to make ubus call
ubus call test hello "{'id':10, 'msg':'Hello World'}"
Expected Output
root#10f23b40deec:/# ubus call test hello "{'id':10, 'msg':'Hello World'}"
{
"message": "test received a message: Hello World"
}
CODE
#include <unistd.h>
#include <uci.h>
#include <uci_blob.h>
#include <libubox/blobmsg_json.h>
#include "libubus.h"
#include <stdlib.h>
static struct ubus_context *ctx;
static struct ubus_subscriber test_event;
static struct blob_buf b;
/*
Enum created to have policy ordered with names
*/
enum {
HELLO_ID,
HELLO_MSG,
__HELLO_MAX
};
/*
Policy stuff, what elements we will return in the JSON
*/
static const struct blobmsg_policy hello_policy[] = {
[HELLO_ID] = { .name = "id", .type = BLOBMSG_TYPE_INT32 },
[HELLO_MSG] = { .name = "msg", .type = BLOBMSG_TYPE_STRING },
};
/*
The request???
*/
struct hello_request {
struct ubus_request_data req;
struct uloop_timeout timeout;
char data[];
};
/*
*
* UCI
*
*/
static int config__(void)
{
struct uci_context *context = NULL;
struct uci_package *package = NULL;
struct uci_section *section = NULL;
context = uci_alloc_context();
uci_load(context, "users", &package);
const char *option = NULL;
section = uci_lookup_section(context, package, "user");
option = uci_lookup_option_string(context, section, "remote_access");
uci_free_context(context);
int res = atoi(option);
return res;
}
/*
*/
static void test_hello_reply(struct uloop_timeout *t)
{
fprintf(stderr, "test_hello_reply Start\n");
struct hello_request *req = container_of(t, struct hello_request, timeout);
blob_buf_init(&b, 0);
char *ch = "message";
blobmsg_add_string(&b, ch , req->data);
ubus_send_reply(ctx, &req->req, b.head);
ubus_complete_deferred_request(ctx, &req->req, 0);
free(req);
fprintf(stderr, "test_hello_reply End\n");
}
/**
The hello callback is this one.
#param ctx - The context??
#param obj - The...??
#param req -
#param method - The name of the method that wants to be called
#param msg -
*/
static int test_hello(struct ubus_context *ctx, struct ubus_object *obj,
struct ubus_request_data *req, const char *method,
struct blob_attr *msg)
{
struct hello_request *hreq;
struct blob_attr *tb[__HELLO_MAX];
const char *format = "%s received a message: %s";
const char *msgstr = "(unknown)";
fprintf(stderr, "test_hello Start\n");
blobmsg_parse(hello_policy, ARRAY_SIZE(hello_policy), tb, blob_data(msg), blob_len(msg));
if (tb[HELLO_MSG])
msgstr = blobmsg_data(tb[HELLO_MSG]);
hreq = calloc(1, sizeof(*hreq) + strlen(format) + strlen(obj->name) + strlen(msgstr) + 1);
sprintf(hreq->data, format, obj->name, msgstr);
ubus_defer_request(ctx, req, &hreq->req);
printf("helloooooo");
hreq->timeout.cb = test_hello_reply;
uloop_timeout_set(&hreq->timeout, 1000);
fprintf(stderr, "test_hello End\n");
return 0;
}
enum {
WATCH_ID,
WATCH_COUNTER,
__WATCH_MAX
};
static const struct blobmsg_policy watch_policy[__WATCH_MAX] = {
[WATCH_ID] = { .name = "id", .type = BLOBMSG_TYPE_INT32 },
[WATCH_COUNTER] = { .name = "counter", .type = BLOBMSG_TYPE_INT32 },
};
static void
test_handle_remove(struct ubus_context *ctx, struct ubus_subscriber *s,
uint32_t id)
{
fprintf(stderr, "test_handle_remove Start\n");
fprintf(stderr, "Object %08x went away\n", id);
fprintf(stderr, "test_handle_remove End\n");
}
/*
When a method is called, displays method and params
*/
static int
test_notify(struct ubus_context *ctx, struct ubus_object *obj,
struct ubus_request_data *req, const char *method,
struct blob_attr *msg)
{
#if 0
char *str;
str = blobmsg_format_json(msg, true);
fprintf(stderr, "Received notification '%s': %s\n", method, str);
free(str);
#endif
fprintf(stderr, "test_notify Start\n");
fprintf(stderr, "test_notify End\n");
return 0;
}
static int test_watch(struct ubus_context *ctx, struct ubus_object *obj,
struct ubus_request_data *req, const char *method,
struct blob_attr *msg)
{
fprintf(stderr, "test_watch Start\n");
struct blob_attr *tb[__WATCH_MAX];
int ret;
blobmsg_parse(watch_policy, __WATCH_MAX, tb, blob_data(msg), blob_len(msg));
if (!tb[WATCH_ID])
return UBUS_STATUS_INVALID_ARGUMENT;
test_event.remove_cb = test_handle_remove; // Action on remove
test_event.cb = test_notify; // Say which is the objective for calls
ret = ubus_subscribe(ctx, &test_event, blobmsg_get_u32(tb[WATCH_ID]));
fprintf(stderr, "Watching object %08x: %s\n", blobmsg_get_u32(tb[WATCH_ID]), ubus_strerror(ret));
fprintf(stderr, "test_watch End\n");
return ret;
}
static const struct ubus_method test_methods[] = {
UBUS_METHOD("hello", test_hello, hello_policy),
UBUS_METHOD("watch", test_watch, watch_policy),
};
static struct ubus_object_type test_object_type =
UBUS_OBJECT_TYPE("test", test_methods);
static struct ubus_object test_object = {
.name = "test",
.type = &test_object_type,
.methods = test_methods,
.n_methods = ARRAY_SIZE(test_methods),
};
static void server_main(void)
{
fprintf(stderr, "server_main Start\n");
int ret;
ret = ubus_add_object(ctx, &test_object);
if (ret)
fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
ret = ubus_register_subscriber(ctx, &test_event);
if (ret)
fprintf(stderr, "Failed to add watch handler: %s\n", ubus_strerror(ret));
uloop_run();
fprintf(stderr, "server_main End\n");
}
int main(int argc, char **argv)
{
const char *ubus_socket = NULL;
int ch;
config__();
while ((ch = getopt(argc, argv, "cs:")) != -1) {
switch (ch) {
case 's':
ubus_socket = optarg;
break;
default:
break;
}
}
argc -= optind;
argv += optind;
uloop_init();
ctx = ubus_connect(ubus_socket);
if (!ctx) {
fprintf(stderr, "Failed to connect to ubus\n");
return -1;
}
ubus_add_uloop(ctx);
server_main();
ubus_free(ctx);
uloop_done();
return 0;
}