Enabling cookies in libwget causes Segmentation Fault

Question

I am trying to learn using libwget on Debian 12. I've installed the package "wget2-dev" which recursively installed "libwget0" package. I wrote a very basic and simple application with the help of wget2 examples.

#include <stdio.h>
#include <stdlib.h>
#include <wget.h>

int main(int argc, char *argv[])
{
    wget_http_connection_t *conn = NULL;
    wget_http_response_t *resp;

    // set up libwget global configuration
    wget_global_init(
        WGET_COOKIES_ENABLED, 1,
        WGET_COOKIE_SUFFIXES, "public_suffixes.txt",
        WGET_COOKIE_FILE, "cookies.txt",
        WGET_COOKIE_KEEPSESSIONCOOKIES, 1,
        0);

    // execute an HTTP GET request and return the response
    resp = wget_http_get(
        WGET_HTTP_URL, "http://example.com",
        WGET_HTTP_MAX_REDIRECTIONS, 5,
        WGET_HTTP_CONNECTION_PTR, &conn,
        0);

    if (resp)
    {
        printf("%s", resp->body->data);

        // free the response
        wget_http_free_response(&resp);
    }
    // close connection if still open
    wget_http_close(&conn);
    // free resources - needed for valgrind testing
    wget_global_deinit();

    return EXIT_SUCCESS;
}

My problem is that, while calling wget_global_init function, if I set "WGET_COOKIES_ENABLED" to "1", I get a Segmentation Fault.

What is the problem here? Is that because of the library or am I doing something wrong? Thanks.

EDIT: I tried the answer in another question related to Segmentation Fault. If I type

gdb ./MyApp

I get

(gdb) run
Starting program: MyApp 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
___pthread_mutex_lock (mutex=0x0) at ./nptl/pthread_mutex_lock.c:80
80  ./nptl/pthread_mutex_lock.c: No such file or directory.

What does that mean? How can I solve it?

EDIT 2: If I type

valgrind --leak-check=full ./MyApp

I get

==42170== Invalid read of size 4
==42170==    at 0x49541C0: pthread_mutex_lock@@GLIBC_2.2.5 (pthread_mutex_lock.c:80)
==42170==    by 0x487A7EC: wget_cookie_create_request_header (in /usr/lib/libwget.so.0.0.0)
==42170==    by 0x4895153: wget_http_get (in /usr/lib/libwget.so.0.0.0)
==42170==    by 0x1091EE: main (main.c:23)
==42170==  Address 0x10 is not stack'd, malloc'd or (recently) free'd
==42170== 
==42170== 
==42170== Process terminating with default action of signal 11 (SIGSEGV)
==42170==  Access not within mapped region at address 0x10
==42170==    at 0x49541C0: pthread_mutex_lock@@GLIBC_2.2.5 (pthread_mutex_lock.c:80)
==42170==    by 0x487A7EC: wget_cookie_create_request_header (in /usr/lib/libwget.so.0.0.0)
==42170==    by 0x4895153: wget_http_get (in /usr/lib/libwget.so.0.0.0)
==42170==    by 0x1091EE: main (main.c:23)

Is that a bug, or am I not using the library correctly?

EDIT 3: After the comment by Olaf Dietsche, I added -lpthread to Build Settings in Eclipse CDT

Invoking: GCC C Compiler
gcc -lpthread -I/usr/include -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/main.d" -MT"src/main.o" -o "src/main.o" "../src/main.c"
Invoking: GCC C Linker
gcc -lpthread -L/usr/lib -o "MyApp" ./src/main.o    -lwget

I am still getting the same error when I run the program.

EDIT 4: I added -lpthread to GCC Linker options too after another comment by Olaf Dietsche. And I am still getting Segmentation Fault.

Answer 1

1. It's a bug in the library (d51398947e150e930299f3c9657aaf6204489f4d) where wget_global_get_ptr() returns a &_config.cookie_db but caller wget_http_get() expects a _config.cookie_db. This fix shipped in v2.0.0 and the current version in Debian is 1.99.1-2.2.

   @rockdaboot mentioned it's fixed in Debian testing so you could install that package from testing.

2. Once you get a fixed version of the library you probably want to specify WGET_COOKIE_FILE which sets WGET_COOKIES_ENABLED.

Please file report a bug to Debian against the package libwget0.

Bonus: It turns out that the wget (binary) doesn't depend on libwget0.