diff options
Diffstat (limited to 'qemu-nbd.c')
-rw-r--r-- | qemu-nbd.c | 68 |
1 files changed, 59 insertions, 9 deletions
@@ -226,8 +226,13 @@ static void *nbd_client_thread(void *arg) /* update partition table */ pthread_create(&show_parts_thread, NULL, show_parts, NULL); - fprintf(stderr, "NBD device %s is now connected to %s\n", - device, srcpath); + if (verbose) { + fprintf(stderr, "NBD device %s is now connected to %s\n", + device, srcpath); + } else { + /* Close stderr so that the qemu-nbd process exits. */ + dup2(STDOUT_FILENO, STDERR_FILENO); + } ret = nbd_client(fd); if (ret) { @@ -406,6 +411,58 @@ int main(int argc, char **argv) return 0; } + if (device && !verbose) { + int stderr_fd[2]; + pid_t pid; + int ret; + + if (qemu_pipe(stderr_fd) == -1) { + err(EXIT_FAILURE, "Error setting up communication pipe"); + } + + /* Now daemonize, but keep a communication channel open to + * print errors and exit with the proper status code. + */ + pid = fork(); + if (pid == 0) { + close(stderr_fd[0]); + ret = qemu_daemon(0, 0); + + /* Temporarily redirect stderr to the parent's pipe... */ + dup2(stderr_fd[1], STDERR_FILENO); + if (ret == -1) { + err(EXIT_FAILURE, "Failed to daemonize"); + } + + /* ... close the descriptor we inherited and go on. */ + close(stderr_fd[1]); + } else { + bool errors = false; + char *buf; + + /* In the parent. Print error messages from the child until + * it closes the pipe. + */ + close(stderr_fd[1]); + buf = g_malloc(1024); + while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { + errors = true; + ret = qemu_write_full(STDERR_FILENO, buf, ret); + if (ret == -1) { + exit(EXIT_FAILURE); + } + } + if (ret == -1) { + err(EXIT_FAILURE, "Cannot read from daemon"); + } + + /* Usually the daemon should not print any message. + * Exit with zero status in that case. + */ + exit(errors); + } + } + bdrv_init(); bs = bdrv_new("hda"); @@ -433,13 +490,6 @@ int main(int argc, char **argv) err(EXIT_FAILURE, "Failed to open %s", device); } - if (!verbose) { - /* detach client and server */ - if (qemu_daemon(0, 0) == -1) { - err(EXIT_FAILURE, "Failed to daemonize"); - } - } - if (sockpath == NULL) { sockpath = g_malloc(128); snprintf(sockpath, 128, SOCKET_PATH, basename(device)); |