execve(): return correct error value when failure (errno)

executer/user/mcexec.c

@@ -344,16 +344,28 @@ int load_elf_desc(char *filename, struct program_load_desc **desc_p)
 	char *interp_path;
 	struct program_load_desc *desc;
 	int ret = 0;
+	struct stat sb;
 
 	if ((ret = access(filename, X_OK)) != 0) {
-		fprintf(stderr, "Error: %s is not an executable?\n", filename);
-		return ret;
+		fprintf(stderr, "Error: %s is not an executable?, errno: %d\n", 
+			filename, errno);
+		return errno;
+	}
+	
+	if ((ret = stat(filename, &sb)) == -1) {
+		fprintf(stderr, "Error: failed to stat %s\n", filename);
+		return errno;
+	}
+	
+	if (sb.st_size == 0) {
+		fprintf(stderr, "Error: file %s is zero length\n", filename);
+		return ENOEXEC;
 	}
 
 	fp = fopen(filename, "rb");
 	if (!fp) {
 		fprintf(stderr, "Error: Failed to open %s\n", filename);
-		return 1;
+		return errno;
 	}
 
 	desc = load_elf(fp, &interp_path);
@@ -1249,6 +1261,11 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 						if (!PATH) {
 							PATH = getenv("PATH");
 						}
+
+						if (strlen(filename) >= 255) {
+							ret = ENAMETOOLONG;
+							goto return_execve1;
+						}
 						
 						__dprintf("PATH: %s\n", PATH);
 
@@ -1278,7 +1295,15 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 						free(tofree);
 					}
 					else {
-						error = snprintf(path, sizeof(path), "%s", filename);
+						char *root = getenv("COKERNEL_EXEC_ROOT");
+						
+						if (root) {
+							error = snprintf(path, sizeof(path), "%s/%s", root, filename);
+						}
+						else {
+							error = snprintf(path, sizeof(path), "%s", filename);
+						}
+
 						if (error < 0 || error >= sizeof(path)) {
 							fprintf(stderr, "execve(): array too small?\n");
 							goto return_execve1;
@@ -1290,6 +1315,7 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 					if (!found) {
 						fprintf(stderr, 
 							"execve(): error finding file %s\n", filename);
+						ret = ENOENT;
 						goto return_execve1;
 					}
 

kernel/syscall.c

@@ -1188,6 +1188,21 @@ SYSCALL_DECLARE(execve)
 	
 	struct syscall_request request IHK_DMA_ALIGN;
 	struct program_load_desc *desc;
+	struct process_vm *vm = cpu_local_var(current)->vm;
+	struct vm_range *range;
+
+	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
+
+	range = lookup_process_memory_range(vm, (unsigned long)filename, 
+			(unsigned long)filename+1);
+
+	if (range == NULL || !(range->flag & VR_PROT_READ)) {
+		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
+		kprintf("execve(): ERROR: filename is bad address\n");
+		return -EFAULT;
+	}
+	
+	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
 
 	desc = ihk_mc_alloc_pages(1, IHK_MC_AP_NOWAIT);
 	if (!desc) {
@@ -1205,8 +1220,9 @@ SYSCALL_DECLARE(execve)
 	ret = do_syscall(&request, ctx, ihk_mc_get_processor_id(), 0);
 
 	if (ret != 0) {
-		kprintf("execve(): ERROR: host failed to load elf header\n");
-		return -EINVAL;
+		kprintf("execve(): ERROR: host failed to load elf header, errno: %d\n", 
+				ret);
+		return -ret;
 	}
 
 	dkprintf("execve(): ELF desc received, num sections: %d\n",