`$LIB` may expand to an incorrect value depending of the distro.

[Samueru-sama]

There was a bug report at Eden that vkbasalt stopped working in version 0.0.3. This is because the vkbasalt json contains this line:

"library_path": "/usr/$LIB/vkbasalt/libvkbasalt.so"

version 0.0.2 was built in ubuntu so in that case the bundled dynamic linker would expand $LIB correctly.

Is there a way that we can configure the bundled dynamic linker to include all possible locations in $LIB?

[Samueru-sama]

Just vibed a solution:

#define _GNU_SOURCE
#include <dlfcn.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

// Original dlopen function pointer
void* (*original_dlopen)(const char* filename, int flags);

// Debug flag (can be enabled via environment variable)
static bool debug_mode = false;

// Our implementation of dlopen that will replace the original
void* dlopen(const char* filename, int flags) {
    // Initialize original_dlopen on first call
    if (!original_dlopen) {
        original_dlopen = dlsym(RTLD_NEXT, "dlopen");
        if (!original_dlopen) {
            fprintf(stderr, "Error getting original dlopen: %s\n", dlerror());
            return NULL;
        }

        // Check for debug environment variable
        const char* debug_env = getenv("DLOPEN_OVERRIDE_DEBUG");
        if (debug_env && (strcmp(debug_env, "1") == 0 || strcmp(debug_env, "true") == 0)) {
            debug_mode = true;
        }
    }

    // If filename doesn't contain $LIB, use original dlopen
    if (!filename || strstr(filename, "$LIB") == NULL) {
        return original_dlopen(filename, flags);
    }

    if (debug_mode) {
        fprintf(stderr, "dlopen override: Intercepted path with $LIB: %s\n", filename);
    }

    // Directories to try for $LIB
    const char* lib_dirs[] = {
        "lib",
        "lib64",
        "lib/x86_64-linux-gnu",
        NULL  // Sentinel value
    };

    // Try each directory
    for (int i = 0; lib_dirs[i] != NULL; i++) {
        char* new_path = strdup(filename);
        if (!new_path) {
            fprintf(stderr, "Memory allocation error\n");
            continue;
        }

        // Replace all occurrences of $LIB with the current directory
        char* lib_ptr;
        while ((lib_ptr = strstr(new_path, "$LIB")) != NULL) {
            char* before = strndup(new_path, lib_ptr - new_path);
            char* after = strdup(lib_ptr + 4);  // Skip "$LIB"

            if (!before || !after) {
                fprintf(stderr, "Memory allocation error\n");
                free(before ? before : NULL);
                free(after ? after : NULL);
                free(new_path);
                goto next_dir;
            }

            char* temp = malloc(strlen(before) + strlen(lib_dirs[i]) + strlen(after) + 1);
            if (!temp) {
                fprintf(stderr, "Memory allocation error\n");
                free(before);
                free(after);
                free(new_path);
                goto next_dir;
            }

            sprintf(temp, "%s%s%s", before, lib_dirs[i], after);
            free(before);
            free(after);
            free(new_path);
            new_path = temp;
        }

        if (debug_mode) {
            fprintf(stderr, "dlopen override: Trying %s\n", new_path);
        }

        // Try to open the library with the replaced path
        void* handle = original_dlopen(new_path, flags);
        if (handle) {
            if (debug_mode) {
                fprintf(stderr, "dlopen override: Successfully loaded %s\n", new_path);
            }
            free(new_path);
            return handle;
        } else if (debug_mode) {
            fprintf(stderr, "dlopen override: Failed to load %s: %s\n", new_path, dlerror());
        }

        free(new_path);
next_dir:
        continue;
    }

    // If no replacement worked, try the original filename
    if (debug_mode) {
        fprintf(stderr, "dlopen override: Falling back to original path: %s\n", filename);
    }
    return original_dlopen(filename, flags);
}

[Samueru-sama]

Worked around the issue in pkgforge-dev/Anylinux-AppImages#71