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Diffstat (limited to 'qemu-nbd.c')
-rw-r--r--qemu-nbd.c298
1 files changed, 192 insertions, 106 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c
index d8d3e15a84..291cba2eaa 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -31,12 +31,17 @@
#include <arpa/inet.h>
#include <signal.h>
#include <libgen.h>
+#include <pthread.h>
#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
#define NBD_BUFFER_SIZE (1024*1024)
+static int sigterm_wfd;
static int verbose;
+static char *device;
+static char *srcpath;
+static char *sockpath;
static void usage(const char *name)
{
@@ -163,21 +168,80 @@ static int find_partition(BlockDriverState *bs, int partition,
return -1;
}
-static void show_parts(const char *device)
+static void termsig_handler(int signum)
{
- if (fork() == 0) {
- int nbd;
+ static int sigterm_reported;
+ if (!sigterm_reported) {
+ sigterm_reported = (write(sigterm_wfd, "", 1) == 1);
+ }
+}
- /* 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 *show_parts(void *arg)
+{
+ 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;
+}
+
+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) {
+ goto out;
+ }
+ } 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);
+
+ 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) {
+ 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)
@@ -192,9 +256,6 @@ int main(int argc, char **argv)
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
- char *device = NULL;
- char *socket = NULL;
- char sockpath[128];
const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
@@ -230,6 +291,21 @@ int main(int argc, char **argv)
int nb_fds = 0;
int max_fd;
int persistent = 0;
+ pthread_t client_thread;
+
+ /* 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) {
+ err(EXIT_FAILURE, "Error setting up communication pipe");
+ }
+
+ sigterm_wfd = sigterm_fd[1];
+ memset(&sa_sigterm, 0, sizeof(sa_sigterm));
+ sa_sigterm.sa_handler = termsig_handler;
+ sigaction(SIGTERM, &sa_sigterm, NULL);
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -273,8 +349,8 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, "Invalid partition %d", partition);
break;
case 'k':
- socket = optarg;
- if (socket[0] != '/')
+ sockpath = optarg;
+ if (sockpath[0] != '/')
errx(EXIT_FAILURE, "socket path must be absolute\n");
break;
case 'd':
@@ -332,130 +408,134 @@ int main(int argc, char **argv)
return 0;
}
- bdrv_init();
-
- bs = bdrv_new("hda");
-
- if ((ret = bdrv_open(bs, argv[optind], flags, NULL)) < 0) {
- errno = -ret;
- err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
- }
-
- fd_size = bs->total_sectors * 512;
-
- if (partition != -1 &&
- find_partition(bs, partition, &dev_offset, &fd_size))
- err(EXIT_FAILURE, "Could not find partition %d", partition);
-
- if (device) {
+ if (device && !verbose) {
+ int stderr_fd[2];
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);
+ if (qemu_pipe(stderr_fd) == -1) {
+ err(EXIT_FAILURE, "Error setting up communication pipe");
}
- if (!verbose) {
- /* detach client and server */
- if (qemu_daemon(0, 0) == -1) {
+ /* 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");
}
- }
-
- if (socket == NULL) {
- snprintf(sockpath, sizeof(sockpath), SOCKET_PATH,
- basename(device));
- socket = sockpath;
- }
- 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(socket);
- if (sock == -1) {
- if (errno != ENOENT && errno != ECONNREFUSED) {
- ret = 1;
- goto out;
- }
- sleep(1); /* wait children */
+ /* ... 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);
}
- } 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;
+ err(EXIT_FAILURE, "Cannot read from daemon");
}
- ret = nbd_init(fd, sock, nbdflags, size, blocksize);
- if (ret == -1) {
- ret = 1;
- goto out;
- }
+ /* Usually the daemon should not print any message.
+ * Exit with zero status in that case.
+ */
+ exit(errors);
+ }
+ }
- printf("NBD device %s is now connected to file %s\n",
- device, argv[optind]);
+ if (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);
+ }
- /* update partition table */
+ if (sockpath == NULL) {
+ sockpath = g_malloc(128);
+ snprintf(sockpath, 128, SOCKET_PATH, basename(device));
+ }
+ }
- show_parts(device);
+ bdrv_init();
+ atexit(bdrv_close_all);
- ret = nbd_client(fd);
- if (ret) {
- ret = 1;
- }
- close(fd);
- out:
- kill(pid, SIGTERM);
- unlink(socket);
+ bs = bdrv_new("hda");
+ srcpath = argv[optind];
+ if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) {
+ errno = -ret;
+ err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
+ }
- return ret;
- }
- /* children */
+ fd_size = bs->total_sectors * 512;
+
+ if (partition != -1 &&
+ find_partition(bs, partition, &dev_offset, &fd_size)) {
+ err(EXIT_FAILURE, "Could not find partition %d", partition);
}
sharing_fds = g_malloc((shared + 1) * sizeof(int));
- if (socket) {
- sharing_fds[0] = unix_socket_incoming(socket);
+ if (sockpath) {
+ sharing_fds[0] = unix_socket_incoming(sockpath);
} else {
sharing_fds[0] = tcp_socket_incoming(bindto, port);
}
if (sharing_fds[0] == -1)
return 1;
+
+ if (device) {
+ int 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));
+ }
+ } else {
+ /* Shut up GCC warnings. */
+ memset(&client_thread, 0, sizeof(client_thread));
+ }
+
max_fd = sharing_fds[0];
nb_fds++;
data = qemu_blockalign(bs, NBD_BUFFER_SIZE);
- if (data == NULL)
+ if (data == NULL) {
errx(EXIT_FAILURE, "Cannot allocate data buffer");
+ }
do {
-
FD_ZERO(&fds);
+ FD_SET(sigterm_fd[0], &fds);
for (i = 0; i < nb_fds; i++)
FD_SET(sharing_fds[i], &fds);
- ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
- if (ret == -1)
+ do {
+ ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
+ } while (ret == -1 && errno == EINTR);
+ if (ret == -1 || FD_ISSET(sigterm_fd[0], &fds)) {
break;
+ }
if (FD_ISSET(sharing_fds[0], &fds))
ret--;
@@ -489,10 +569,16 @@ int main(int argc, char **argv)
qemu_vfree(data);
close(sharing_fds[0]);
- bdrv_close(bs);
g_free(sharing_fds);
- if (socket)
- unlink(socket);
+ if (sockpath) {
+ unlink(sockpath);
+ }
- return 0;
+ if (device) {
+ void *ret;
+ pthread_join(client_thread, &ret);
+ exit(ret != NULL);
+ } else {
+ exit(EXIT_SUCCESS);
+ }
}
generated by cgit v1.2.1 (git 2.18.0) at 2024-05-26 14:16:19 +0000