diff options
Diffstat (limited to 'lib/ulockmgr.c')
| -rw-r--r-- | lib/ulockmgr.c | 702 |
1 files changed, 352 insertions, 350 deletions
diff --git a/lib/ulockmgr.c b/lib/ulockmgr.c index e38fdc5..6703cd0 100644 --- a/lib/ulockmgr.c +++ b/lib/ulockmgr.c @@ -1,9 +1,9 @@ /* - libulockmgr: Userspace Lock Manager Library - Copyright (C) 2006 Miklos Szeredi <miklos@szeredi.hu> + libulockmgr: Userspace Lock Manager Library + Copyright (C) 2006 Miklos Szeredi <miklos@szeredi.hu> - This program can be distributed under the terms of the GNU LGPLv2. - See the file COPYING.LIB + This program can be distributed under the terms of the GNU LGPLv2. + See the file COPYING.LIB */ /* #define DEBUG 1 */ @@ -22,28 +22,28 @@ #include <sys/wait.h> struct message { - unsigned intr : 1; - unsigned nofd : 1; - pthread_t thr; - int cmd; - int fd; - struct flock lock; - int error; + unsigned intr : 1; + unsigned nofd : 1; + pthread_t thr; + int cmd; + int fd; + struct flock lock; + int error; }; struct fd_store { - struct fd_store *next; - int fd; - int inuse; + struct fd_store *next; + int fd; + int inuse; }; struct owner { - struct owner *next; - struct owner *prev; - struct fd_store *fds; - void *id; - size_t id_len; - int cfd; + struct owner *next; + struct owner *prev; + struct fd_store *fds; + void *id; + size_t id_len; + int cfd; }; static pthread_mutex_t ulockmgr_lock; @@ -54,19 +54,19 @@ static struct owner owner_list = { .next = &owner_list, .prev = &owner_list }; static void list_del_owner(struct owner *owner) { - struct owner *prev = owner->prev; - struct owner *next = owner->next; - prev->next = next; - next->prev = prev; + struct owner *prev = owner->prev; + struct owner *next = owner->next; + prev->next = next; + next->prev = prev; } static void list_add_owner(struct owner *owner, struct owner *next) { - struct owner *prev = next->prev; - owner->next = next; - owner->prev = prev; - prev->next = owner; - next->prev = owner; + struct owner *prev = next->prev; + owner->next = next; + owner->prev = prev; + prev->next = owner; + next->prev = owner; } /* @@ -74,365 +74,367 @@ static void list_add_owner(struct owner *owner, struct owner *next) * on AF_UNIX, SOCK_STREAM sockets, that could cause it to return * zero, even if data was available. Retrying the recv will return * the data in this case. -*/ + */ static int do_recv(int sock, void *buf, size_t len, int flags) { - int res = recv(sock, buf, len, flags); - if (res == 0) - res = recv(sock, buf, len, flags); + int res = recv(sock, buf, len, flags); + if (res == 0) + res = recv(sock, buf, len, flags); - return res; + return res; } static int ulockmgr_send_message(int sock, void *buf, size_t buflen, - int *fdp, int numfds) + int *fdp, int numfds) { - struct msghdr msg; - struct cmsghdr *p_cmsg; - struct iovec vec; - size_t cmsgbuf[CMSG_SPACE(sizeof(int) * MAX_SEND_FDS) / sizeof(size_t)]; - int res; - - assert(numfds <= MAX_SEND_FDS); - msg.msg_control = cmsgbuf; - msg.msg_controllen = sizeof(cmsgbuf); - p_cmsg = CMSG_FIRSTHDR(&msg); - p_cmsg->cmsg_level = SOL_SOCKET; - p_cmsg->cmsg_type = SCM_RIGHTS; - p_cmsg->cmsg_len = CMSG_LEN(sizeof(int) * numfds); - memcpy(CMSG_DATA(p_cmsg), fdp, sizeof(int) * numfds); - msg.msg_controllen = p_cmsg->cmsg_len; - msg.msg_name = NULL; - msg.msg_namelen = 0; - msg.msg_iov = &vec; - msg.msg_iovlen = 1; - msg.msg_flags = 0; - vec.iov_base = buf; - vec.iov_len = buflen; - res = sendmsg(sock, &msg, MSG_NOSIGNAL); - if (res == -1) { - perror("libulockmgr: sendmsg"); - return -1; - } - if ((size_t) res != buflen) { - fprintf(stderr, "libulockmgr: sendmsg short\n"); - return -1; - } - return 0; + struct msghdr msg; + struct cmsghdr *p_cmsg; + struct iovec vec; + size_t cmsgbuf[CMSG_SPACE(sizeof(int) * MAX_SEND_FDS) / sizeof(size_t)]; + int res; + + assert(numfds <= MAX_SEND_FDS); + msg.msg_control = cmsgbuf; + msg.msg_controllen = sizeof(cmsgbuf); + p_cmsg = CMSG_FIRSTHDR(&msg); + p_cmsg->cmsg_level = SOL_SOCKET; + p_cmsg->cmsg_type = SCM_RIGHTS; + p_cmsg->cmsg_len = CMSG_LEN(sizeof(int) * numfds); + memcpy(CMSG_DATA(p_cmsg), fdp, sizeof(int) * numfds); + msg.msg_controllen = p_cmsg->cmsg_len; + msg.msg_name = NULL; + msg.msg_namelen = 0; + msg.msg_iov = &vec; + msg.msg_iovlen = 1; + msg.msg_flags = 0; + vec.iov_base = buf; + vec.iov_len = buflen; + res = sendmsg(sock, &msg, MSG_NOSIGNAL); + if (res == -1) { + perror("libulockmgr: sendmsg"); + return -1; + } + if ((size_t) res != buflen) { + fprintf(stderr, "libulockmgr: sendmsg short\n"); + return -1; + } + return 0; } static int ulockmgr_start_daemon(void) { - int sv[2]; - int res; - char tmp[64]; - - res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); - if (res == -1) { - perror("libulockmgr: socketpair"); - return -1; - } - snprintf(tmp, sizeof(tmp), "exec ulockmgr_server %i", sv[0]); - res = system(tmp); - close(sv[0]); - if (res == -1 || !WIFEXITED(res) || WEXITSTATUS(res) != 0) { - close(sv[1]); - return -1; - } - ulockmgr_cfd = sv[1]; - return 0; + int sv[2]; + int res; + char tmp[64]; + + res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); + if (res == -1) { + perror("libulockmgr: socketpair"); + return -1; + } + snprintf(tmp, sizeof(tmp), "exec ulockmgr_server %i", sv[0]); + res = system(tmp); + close(sv[0]); + if (res == -1 || !WIFEXITED(res) || WEXITSTATUS(res) != 0) { + close(sv[1]); + return -1; + } + ulockmgr_cfd = sv[1]; + return 0; } static struct owner *ulockmgr_new_owner(const void *id, size_t id_len) { - int sv[2]; - int res; - char c = 'm'; - struct owner *o; - - if (ulockmgr_cfd == -1 && ulockmgr_start_daemon() == -1) - return NULL; - - o = calloc(1, sizeof(struct owner) + id_len); - if (!o) { - fprintf(stderr, "libulockmgr: failed to allocate memory\n"); - return NULL; - } - o->id = o + 1; - o->id_len = id_len; - res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); - if (res == -1) { - perror("libulockmgr: socketpair"); - goto out_free; - } - res = ulockmgr_send_message(ulockmgr_cfd, &c, sizeof(c), &sv[0], 1); - close(sv[0]); - if (res == -1) { - close(ulockmgr_cfd); - ulockmgr_cfd = -1; - goto out_close; - } - - o->cfd = sv[1]; - memcpy(o->id, id, id_len); - list_add_owner(o, &owner_list); - - return o; - - out_close: - close(sv[1]); - out_free: - free(o); - return NULL; + int sv[2]; + int res; + char c = 'm'; + struct owner *o; + + if (ulockmgr_cfd == -1 && ulockmgr_start_daemon() == -1) + return NULL; + + o = calloc(1, sizeof(struct owner) + id_len); + if (!o) { + fprintf(stderr, "libulockmgr: failed to allocate memory\n"); + return NULL; + } + o->id = o + 1; + o->id_len = id_len; + res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); + if (res == -1) { + perror("libulockmgr: socketpair"); + goto out_free; + } + res = ulockmgr_send_message(ulockmgr_cfd, &c, sizeof(c), &sv[0], 1); + close(sv[0]); + if (res == -1) { + close(ulockmgr_cfd); + ulockmgr_cfd = -1; + goto out_close; + } + + o->cfd = sv[1]; + memcpy(o->id, id, id_len); + list_add_owner(o, &owner_list); + + return o; + +out_close: + close(sv[1]); +out_free: + free(o); + return NULL; } static int ulockmgr_send_request(struct message *msg, const void *id, - size_t id_len) + size_t id_len) { - int sv[2]; - int cfd; - struct owner *o; - struct fd_store *f = NULL; - struct fd_store *newf = NULL; - struct fd_store **fp; - int fd = msg->fd; - int cmd = msg->cmd; - int res; - int unlockall = (cmd == F_SETLK && msg->lock.l_type == F_UNLCK && - msg->lock.l_start == 0 && msg->lock.l_len == 0); - - for (o = owner_list.next; o != &owner_list; o = o->next) - if (o->id_len == id_len && memcmp(o->id, id, id_len) == 0) - break; - - if (o == &owner_list) - o = NULL; - - if (!o && cmd != F_GETLK && msg->lock.l_type != F_UNLCK) - o = ulockmgr_new_owner(id, id_len); - - if (!o) { - if (cmd == F_GETLK) { - res = fcntl(msg->fd, F_GETLK, &msg->lock); - return (res == -1) ? -errno : 0; - } else if (msg->lock.l_type == F_UNLCK) - return 0; - else - return -ENOLCK; - } - - if (unlockall) - msg->nofd = 1; - else { - for (fp = &o->fds; *fp; fp = &(*fp)->next) { - f = *fp; - if (f->fd == fd) { - msg->nofd = 1; - break; - } - } - } - - if (!msg->nofd) { - newf = f = calloc(1, sizeof(struct fd_store)); - if (!f) { - fprintf(stderr, "libulockmgr: failed to allocate memory\n"); - return -ENOLCK; - } - } - - res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); - if (res == -1) { - perror("libulockmgr: socketpair"); - free(newf); - return -ENOLCK; - } - - cfd = sv[1]; - sv[1] = msg->fd; - res = ulockmgr_send_message(o->cfd, msg, sizeof(struct message), sv, - msg->nofd ? 1 : 2); - close(sv[0]); - if (res == -1) { - free(newf); - close(cfd); - return -EIO; - } - - if (newf) { - newf->fd = msg->fd; - newf->next = o->fds; - o->fds = newf; - } - if (f) - f->inuse++; - - res = do_recv(cfd, msg, sizeof(struct message), MSG_WAITALL); - if (res == -1) { - perror("libulockmgr: recv"); - msg->error = EIO; - } else if (res != sizeof(struct message)) { - fprintf(stderr, "libulockmgr: recv short\n"); - msg->error = EIO; - } else if (cmd == F_SETLKW && msg->error == EAGAIN) { - pthread_mutex_unlock(&ulockmgr_lock); - while (1) { - sigset_t old; - sigset_t unblock; - int errno_save; - - sigemptyset(&unblock); - sigaddset(&unblock, SIGUSR1); - pthread_sigmask(SIG_UNBLOCK, &unblock, &old); - res = do_recv(cfd, msg, sizeof(struct message), MSG_WAITALL); - errno_save = errno; - pthread_sigmask(SIG_SETMASK, &old, NULL); - if (res == sizeof(struct message)) - break; - else if (res >= 0) { - fprintf(stderr, "libulockmgr: recv short\n"); - msg->error = EIO; - break; - } else if (errno_save != EINTR) { - errno = errno_save; - perror("libulockmgr: recv"); - msg->error = EIO; - break; - } - msg->intr = 1; - res = send(o->cfd, msg, sizeof(struct message), MSG_NOSIGNAL); - if (res == -1) { - perror("libulockmgr: send"); - msg->error = EIO; - break; - } - if (res != sizeof(struct message)) { - fprintf(stderr, "libulockmgr: send short\n"); - msg->error = EIO; - break; - } - } - pthread_mutex_lock(&ulockmgr_lock); - - } - if (f) - f->inuse--; - close(cfd); - if (unlockall) { - for (fp = &o->fds; *fp;) { - f = *fp; - if (f->fd == fd && !f->inuse) { - *fp = f->next; - free(f); - } else - fp = &f->next; - } - if (!o->fds) { - list_del_owner(o); - close(o->cfd); - free(o); - } - /* Force OK on unlock-all, since it _will_ succeed once the - owner is deleted */ - msg->error = 0; - } - - return -msg->error; + int sv[2]; + int cfd; + struct owner *o; + struct fd_store *f = NULL; + struct fd_store *newf = NULL; + struct fd_store **fp; + int fd = msg->fd; + int cmd = msg->cmd; + int res; + int unlockall = (cmd == F_SETLK && msg->lock.l_type == F_UNLCK && + msg->lock.l_start == 0 && msg->lock.l_len == 0); + + for (o = owner_list.next; o != &owner_list; o = o->next) + if (o->id_len == id_len && memcmp(o->id, id, id_len) == 0) + break; + + if (o == &owner_list) + o = NULL; + + if (!o && cmd != F_GETLK && msg->lock.l_type != F_UNLCK) + o = ulockmgr_new_owner(id, id_len); + + if (!o) { + if (cmd == F_GETLK) { + res = fcntl(msg->fd, F_GETLK, &msg->lock); + return (res == -1) ? -errno : 0; + } else if (msg->lock.l_type == F_UNLCK) + return 0; + else + return -ENOLCK; + } + + if (unlockall) + msg->nofd = 1; + else { + for (fp = &o->fds; *fp; fp = &(*fp)->next) { + f = *fp; + if (f->fd == fd) { + msg->nofd = 1; + break; + } + } + } + + if (!msg->nofd) { + newf = f = calloc(1, sizeof(struct fd_store)); + if (!f) { + fprintf(stderr, "libulockmgr: failed to allocate memory\n"); + return -ENOLCK; + } + } + + res = socketpair(AF_UNIX, SOCK_STREAM, 0, sv); + if (res == -1) { + perror("libulockmgr: socketpair"); + free(newf); + return -ENOLCK; + } + + cfd = sv[1]; + sv[1] = msg->fd; + res = ulockmgr_send_message(o->cfd, msg, sizeof(struct message), sv, + msg->nofd ? 1 : 2); + close(sv[0]); + if (res == -1) { + free(newf); + close(cfd); + return -EIO; + } + + if (newf) { + newf->fd = msg->fd; + newf->next = o->fds; + o->fds = newf; + } + if (f) + f->inuse++; + + res = do_recv(cfd, msg, sizeof(struct message), MSG_WAITALL); + if (res == -1) { + perror("libulockmgr: recv"); + msg->error = EIO; + } else if (res != sizeof(struct message)) { + fprintf(stderr, "libulockmgr: recv short\n"); + msg->error = EIO; + } else if (cmd == F_SETLKW && msg->error == EAGAIN) { + pthread_mutex_unlock(&ulockmgr_lock); + while (1) { + sigset_t old; + sigset_t unblock; + int errno_save; + + sigemptyset(&unblock); + sigaddset(&unblock, SIGUSR1); + pthread_sigmask(SIG_UNBLOCK, &unblock, &old); + res = do_recv(cfd, msg, sizeof(struct message), + MSG_WAITALL); + errno_save = errno; + pthread_sigmask(SIG_SETMASK, &old, NULL); + if (res == sizeof(struct message)) + break; + else if (res >= 0) { + fprintf(stderr, "libulockmgr: recv short\n"); + msg->error = EIO; + break; + } else if (errno_save != EINTR) { + errno = errno_save; + perror("libulockmgr: recv"); + msg->error = EIO; + break; + } + msg->intr = 1; + res = send(o->cfd, msg, sizeof(struct message), + MSG_NOSIGNAL); + if (res == -1) { + perror("libulockmgr: send"); + msg->error = EIO; + break; + } + if (res != sizeof(struct message)) { + fprintf(stderr, "libulockmgr: send short\n"); + msg->error = EIO; + break; + } + } + pthread_mutex_lock(&ulockmgr_lock); + + } + if (f) + f->inuse--; + close(cfd); + if (unlockall) { + for (fp = &o->fds; *fp;) { + f = *fp; + if (f->fd == fd && !f->inuse) { + *fp = f->next; + free(f); + } else + fp = &f->next; + } + if (!o->fds) { + list_del_owner(o); + close(o->cfd); + free(o); + } + /* Force OK on unlock-all, since it _will_ succeed once the + owner is deleted */ + msg->error = 0; + } + + return -msg->error; } #ifdef DEBUG static uint32_t owner_hash(const unsigned char *id, size_t id_len) { - uint32_t h = 0; - size_t i; - for (i = 0; i < id_len; i++) - h = ((h << 8) | (h >> 24)) ^ id[i]; + uint32_t h = 0; + size_t i; + for (i = 0; i < id_len; i++) + h = ((h << 8) | (h >> 24)) ^ id[i]; - return h; + return h; } #endif static int ulockmgr_canonicalize(int fd, struct flock *lock) { - off_t offset; - if (lock->l_whence == SEEK_CUR) { - offset = lseek(fd, 0, SEEK_CUR); - if (offset == (off_t) -1) - return -errno; - } else if (lock->l_whence == SEEK_END) { - struct stat stbuf; - int res = fstat(fd, &stbuf); - if (res == -1) - return -errno; - - offset = stbuf.st_size; - } else - offset = 0; - - lock->l_whence = SEEK_SET; - lock->l_start += offset; - - if (lock->l_start < 0) - return -EINVAL; - - if (lock->l_len < 0) { - lock->l_start += lock->l_len; - if (lock->l_start < 0) - return -EINVAL; - lock->l_len = -lock->l_len; - } - if (lock->l_len && lock->l_start + lock->l_len - 1 < 0) - return -EINVAL; - - return 0; + off_t offset; + if (lock->l_whence == SEEK_CUR) { + offset = lseek(fd, 0, SEEK_CUR); + if (offset == (off_t) -1) + return -errno; + } else if (lock->l_whence == SEEK_END) { + struct stat stbuf; + int res = fstat(fd, &stbuf); + if (res == -1) + return -errno; + + offset = stbuf.st_size; + } else + offset = 0; + + lock->l_whence = SEEK_SET; + lock->l_start += offset; + + if (lock->l_start < 0) + return -EINVAL; + + if (lock->l_len < 0) { + lock->l_start += lock->l_len; + if (lock->l_start < 0) + return -EINVAL; + lock->l_len = -lock->l_len; + } + if (lock->l_len && lock->l_start + lock->l_len - 1 < 0) + return -EINVAL; + + return 0; } int ulockmgr_op(int fd, int cmd, struct flock *lock, const void *owner, - size_t owner_len) + size_t owner_len) { - int err; - struct message msg; - sigset_t old; - sigset_t block; + int err; + struct message msg; + sigset_t old; + sigset_t block; - if (cmd != F_GETLK && cmd != F_SETLK && cmd != F_SETLKW) - return -EINVAL; + if (cmd != F_GETLK && cmd != F_SETLK && cmd != F_SETLKW) + return -EINVAL; - if (lock->l_whence != SEEK_SET && lock->l_whence != SEEK_CUR && - lock->l_whence != SEEK_END) - return -EINVAL; + if (lock->l_whence != SEEK_SET && lock->l_whence != SEEK_CUR && + lock->l_whence != SEEK_END) + return -EINVAL; #ifdef DEBUG - fprintf(stderr, "libulockmgr: %i %i %i %lli %lli own: 0x%08x\n", - cmd, lock->l_type, lock->l_whence, lock->l_start, lock->l_len, - owner_hash(owner, owner_len)); + fprintf(stderr, "libulockmgr: %i %i %i %lli %lli own: 0x%08x\n", + cmd, lock->l_type, lock->l_whence, lock->l_start, lock->l_len, + owner_hash(owner, owner_len)); #endif - /* Unlock should never block anyway */ - if (cmd == F_SETLKW && lock->l_type == F_UNLCK) - cmd = F_SETLK; - - memset(&msg, 0, sizeof(struct message)); - msg.cmd = cmd; - msg.fd = fd; - msg.lock = *lock; - err = ulockmgr_canonicalize(fd, &msg.lock); - if (err) - return err; - - sigemptyset(&block); - sigaddset(&block, SIGUSR1); - pthread_sigmask(SIG_BLOCK, &block, &old); - pthread_mutex_lock(&ulockmgr_lock); - err = ulockmgr_send_request(&msg, owner, owner_len); - pthread_mutex_unlock(&ulockmgr_lock); - pthread_sigmask(SIG_SETMASK, &old, NULL); - if (!err && cmd == F_GETLK) { - if (msg.lock.l_type == F_UNLCK) - lock->l_type = F_UNLCK; - else - *lock = msg.lock; - } - - return err; + /* Unlock should never block anyway */ + if (cmd == F_SETLKW && lock->l_type == F_UNLCK) + cmd = F_SETLK; + + memset(&msg, 0, sizeof(struct message)); + msg.cmd = cmd; + msg.fd = fd; + msg.lock = *lock; + err = ulockmgr_canonicalize(fd, &msg.lock); + if (err) + return err; + + sigemptyset(&block); + sigaddset(&block, SIGUSR1); + pthread_sigmask(SIG_BLOCK, &block, &old); + pthread_mutex_lock(&ulockmgr_lock); + err = ulockmgr_send_request(&msg, owner, owner_len); + pthread_mutex_unlock(&ulockmgr_lock); + pthread_sigmask(SIG_SETMASK, &old, NULL); + if (!err && cmd == F_GETLK) { + if (msg.lock.l_type == F_UNLCK) + lock->l_type = F_UNLCK; + else + *lock = msg.lock; + } + + return err; } |