diff options
| -rw-r--r-- | qemu-nbd.c | 173 |
1 files changed, 93 insertions, 80 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c index 20b69c1507..ffc2a8ae68 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -31,6 +31,7 @@ #include <arpa/inet.h> #include <signal.h> #include <libgen.h> +#include <pthread.h> #define SOCKET_PATH "/var/lock/qemu-nbd-%s" @@ -38,6 +39,9 @@ static int sigterm_wfd; static int verbose; +static char *device; +static char *srcpath; +static char *sockpath; static void usage(const char *name) { @@ -172,21 +176,70 @@ static void termsig_handler(int signum) } } -static void show_parts(const char *device) +static void *show_parts(void *arg) { - if (fork() == 0) { - int nbd; + int nbd; + + /* linux just needs an open() to trigger + * the partition table update + * but remember to load the module with max_part != 0 : + * modprobe nbd max_part=63 + */ + nbd = open(device, O_RDWR); + if (nbd != -1) { + close(nbd); + } + return NULL; +} - /* linux just needs an open() to trigger - * the partition table update - * but remember to load the module with max_part != 0 : - * modprobe nbd max_part=63 - */ - nbd = open(device, O_RDWR); - if (nbd != -1) - close(nbd); - exit(0); +static void *nbd_client_thread(void *arg) +{ + int fd = *(int *)arg; + off_t size; + size_t blocksize; + uint32_t nbdflags; + int sock; + int ret; + pthread_t show_parts_thread; + + do { + sock = unix_socket_outgoing(sockpath); + if (sock == -1) { + if (errno != ENOENT && errno != ECONNREFUSED) { + goto out; + } + sleep(1); /* wait parent */ + } + } while (sock == -1); + + ret = nbd_receive_negotiate(sock, NULL, &nbdflags, + &size, &blocksize); + if (ret == -1) { + goto out; + } + + ret = nbd_init(fd, sock, nbdflags, size, blocksize); + if (ret == -1) { + goto out; + } + + /* 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); + + ret = nbd_client(fd); + if (ret) { + goto out; } + close(fd); + kill(getpid(), SIGTERM); + return (void *) EXIT_SUCCESS; + +out: + kill(getpid(), SIGTERM); + return (void *) EXIT_FAILURE; } int main(int argc, char **argv) @@ -201,8 +254,6 @@ int main(int argc, char **argv) struct sockaddr_in addr; socklen_t addr_len = sizeof(addr); off_t fd_size; - char *device = NULL; - char *sockpath = NULL; const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; struct option lopt[] = { { "help", 0, NULL, 'h' }, @@ -238,8 +289,11 @@ int main(int argc, char **argv) int nb_fds = 0; int max_fd; int persistent = 0; + pthread_t client_thread; - /* Set up a SIGTERM handler so that we exit with a nice status code. */ + /* The client thread uses SIGTERM to interrupt the server. A signal + * handler ensures that "qemu-nbd -v -c" exits with a nice status code. + */ struct sigaction sa_sigterm; int sigterm_fd[2]; if (qemu_pipe(sigterm_fd) == -1) { @@ -356,9 +410,10 @@ int main(int argc, char **argv) bs = bdrv_new("hda"); - if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) { + srcpath = argv[optind]; + if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) { errno = -ret; - err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]); + err(EXIT_FAILURE, "Failed to bdrv_open '%s'", srcpath); } fd_size = bs->total_sectors * 512; @@ -368,12 +423,14 @@ int main(int argc, char **argv) err(EXIT_FAILURE, "Could not find partition %d", partition); if (device) { - pid_t pid; - int sock; + int ret; - /* want to fail before daemonizing */ - if (access(device, R_OK|W_OK) == -1) { - err(EXIT_FAILURE, "Could not access '%s'", device); + /* Open before spawning new threads. In the future, we may + * drop privileges after opening. + */ + fd = open(device, O_RDWR); + if (fd == -1) { + err(EXIT_FAILURE, "Failed to open %s", device); } if (!verbose) { @@ -388,64 +445,14 @@ int main(int argc, char **argv) snprintf(sockpath, 128, SOCKET_PATH, basename(device)); } - pid = fork(); - if (pid < 0) - return 1; - if (pid != 0) { - off_t size; - size_t blocksize; - - ret = 0; - bdrv_close(bs); - - do { - sock = unix_socket_outgoing(sockpath); - if (sock == -1) { - if (errno != ENOENT && errno != ECONNREFUSED) { - ret = 1; - goto out; - } - sleep(1); /* wait children */ - } - } while (sock == -1); - - fd = open(device, O_RDWR); - if (fd == -1) { - ret = 1; - goto out; - } - - ret = nbd_receive_negotiate(sock, NULL, &nbdflags, - &size, &blocksize); - if (ret == -1) { - ret = 1; - goto out; - } - - ret = nbd_init(fd, sock, nbdflags, size, blocksize); - if (ret == -1) { - ret = 1; - goto out; - } - - printf("NBD device %s is now connected to file %s\n", - device, argv[optind]); - - /* update partition table */ - - show_parts(device); - - ret = nbd_client(fd); - if (ret) { - ret = 1; - } - close(fd); - out: - kill(pid, SIGTERM); - - return ret; + ret = pthread_create(&client_thread, NULL, nbd_client_thread, &fd); + if (ret != 0) { + errx(EXIT_FAILURE, "Failed to create client thread: %s", + strerror(ret)); } - /* children */ + } else { + /* Shut up GCC warnings. */ + memset(&client_thread, 0, sizeof(client_thread)); } sharing_fds = g_malloc((shared + 1) * sizeof(int)); @@ -517,5 +524,11 @@ int main(int argc, char **argv) unlink(sockpath); } - return 0; + if (device) { + void *ret; + pthread_join(client_thread, &ret); + exit(ret != NULL); + } else { + exit(EXIT_SUCCESS); + } } |