online compiler and debugger for c/c++

#include <dlfcn.h> #include <err.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <setjmp.h> #include <signal.h> typedef void (*demo_func_t)(void); #define TEMPLATE_PATH "/tmp/dynlink_XXXXXX" #define MAX_LINE 1024 #define COMPILE_CMD "gcc -shared -fPIC -o %s %s" static void generate_source(const char *filename, const char *user_code) { FILE *fp; if ((fp = fopen(filename, "w")) == NULL) err(1, "fopen"); fprintf(fp, "#include <stdio.h>\n#include <unistd.h>\n" "#include <fcntl.h>\n#include <stddef.h>\n" "#include <stdint.h>\n#include <stdlib.h>\n\n" "void demo_function(void)\n" "{\n" " %s\n" "}\n", user_code); fclose(fp); } static char * create_temp_file(const char *suffix) { char *filename; int fd; /* Allocate space for template + suffix + null terminator */ if (!(filename = malloc(strlen(TEMPLATE_PATH) + strlen(suffix) + 1))) err(1, "malloc"); strcpy(filename, TEMPLATE_PATH); if ((fd = mkstemp(filename)) == -1) err(1, "mkstemp"); close(fd); /* Add suffix to the generated filename */ strcat(filename, suffix); return filename; } static int compile_shared_object(const char *src_file, const char *so_file) { char cmd[MAX_LINE]; snprintf(cmd, sizeof(cmd), COMPILE_CMD, so_file, src_file); printf("[DEBUG] Compiling with command: %s\n", cmd); return system(cmd); } static char *src_file, *so_file; static void zap_files(void) { if (src_file) { unlink(src_file); free(src_file); src_file = NULL; } if (so_file) { unlink(so_file); free(so_file); so_file = NULL; } } /* Signal handlers for Alarm, Segmentation fault, Bus error */ jmp_buf give_up; static void sig_alarm(int signo) { fprintf(stderr, "Timeout: Execution took too long\n"); longjmp(give_up, 1); } static void sig_mem(int signo) { fprintf(stderr, "Memory access error\n"); longjmp(give_up, 1); } int main(void) { char *line; void *handle; demo_func_t func; const char *error; size_t linelen = 0; /* Set up cleanup handler */ atexit(zap_files); while (1) { printf("Enter one line of C code (for function body):\n" "(e.g., --> printf(\"Hello, world!\\n\"); <-- )\n" "Type 'exit(0);' to quit\n"); if ((linelen = getline(&line, &linelen, stdin)) == -1) err(1, "getline"); /* Create temporary source and shared object files */ src_file = create_temp_file(".c"); so_file = strdup("./temp.so"); printf("[DEBUG] Temporary files: Source = %s, " "Shared object: %s\n", src_file, so_file); /* Generate and compile the source */ generate_source(src_file, line); printf("[DEBUG] Generated source file with user code\n"); if (compile_shared_object(src_file, so_file) != 0) { fprintf(stderr, "Compilation failed\n"); goto cleanup; } printf("[DEBUG] Compilation successful\n"); /* Load the shared object */ handle = dlopen(so_file, RTLD_NOW); if (handle == NULL) { fprintf(stderr, "dlopen failed: %s\n", dlerror()); goto cleanup; } printf("[DEBUG] Loaded shared object at %p\n", handle); /* Get the function symbol */ func = (demo_func_t)dlsym(handle, "demo_function"); if ((error = dlerror()) != NULL) { fprintf(stderr, "dlsym failed: %s\n", error); dlclose(handle); goto cleanup; } printf("[DEBUG] Retrieved function symbol at %p\n", (void *)func); /* Execute the function */ printf("\nExecuting user function:\n"); printf("--------------------\n"); /* Protect against infinite loops and some bad memory access */ if (setjmp(give_up) == 0) { signal(SIGALRM, sig_alarm); signal(SIGSEGV, sig_mem); signal(SIGBUS, sig_mem); alarm(3); func(); alarm(0); signal(SIGALRM, SIG_DFL); signal(SIGSEGV, SIG_DFL); signal(SIGBUS, SIG_DFL); } printf("--------------------\n"); /* Cleanup */ dlclose(handle); printf("[DEBUG] Unloaded shared object\n"); cleanup: zap_files(); printf("[DEBUG] Removed temporary files\n"); } return 0; }