/* $NetBSD: autofs_linux.c,v 1.1.1.3 2015/01/17 16:34:16 christos Exp $ */ /* * Copyright (c) 1999-2003 Ion Badulescu * Copyright (c) 1997-2014 Erez Zadok * Copyright (c) 1990 Jan-Simon Pendry * Copyright (c) 1990 Imperial College of Science, Technology & Medicine * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry at Imperial College, London. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * * File: am-utils/conf/autofs/autofs_linux.c * */ /* * Automounter filesystem for Linux */ #ifdef HAVE_CONFIG_H # include #endif /* HAVE_CONFIG_H */ #include #include #ifdef HAVE_FS_AUTOFS /* * MACROS: */ #define AUTOFS_MIN_VERSION 3 #if AUTOFS_MAX_PROTO_VERSION >= 5 /* * Autofs version 5 support is experimental; change this to 5 you want * to play with, it. There are reports it does not work. */ #define AUTOFS_MAX_VERSION 4 /* we only know up to version 5 */ #else #define AUTOFS_MAX_VERSION AUTOFS_MAX_PROTO_VERSION #endif /* * STRUCTURES: */ /* * VARIABLES: */ static int autofs_max_fds; static am_node **hash; static int *list; static int numfds = 0; static int bind_works = 1; static void hash_init(void) { int i; struct rlimit rlim; if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) { plog(XLOG_ERROR, "getrlimit failed, defaulting to 256 fd's"); autofs_max_fds = 256; } else { autofs_max_fds = (rlim.rlim_cur > 1024) ? 1024 : rlim.rlim_cur; plog(XLOG_INFO, "%d fd's available for autofs", autofs_max_fds); } list = malloc(autofs_max_fds * sizeof(*list)); hash = malloc(autofs_max_fds * sizeof(*hash)); for (i = 0 ; i < autofs_max_fds; i++) { hash[i] = NULL; list[i] = -1; } } static void hash_insert(int fd, am_node *mp) { if (hash[fd] != 0) plog(XLOG_ERROR, "file descriptor %d already in the hash", fd); hash[fd] = mp; list[numfds] = fd; numfds++; } static void hash_delete(int fd) { int i; if (hash[fd] == 0) plog(XLOG_WARNING, "file descriptor %d not in the hash", fd); hash[fd] = NULL; numfds--; for (i = 0; i < numfds; i++) if (list[i] == fd) { list[i] = list[numfds]; break; } } int autofs_get_fh(am_node *mp) { int fds[2]; autofs_fh_t *fh; plog(XLOG_DEBUG, "autofs_get_fh for %s", mp->am_path); if (pipe(fds) < 0) return errno; /* sanity check */ if (fds[0] > autofs_max_fds) { close(fds[0]); close(fds[1]); return EMFILE; } fh = ALLOC(autofs_fh_t); fh->fd = fds[0]; fh->kernelfd = fds[1]; fh->ioctlfd = -1; fh->pending_mounts = NULL; fh->pending_umounts = NULL; mp->am_autofs_fh = fh; return 0; } void autofs_mounted(am_node *mp) { autofs_fh_t *fh = mp->am_autofs_fh; unsigned long timeout = gopt.am_timeo; close(fh->kernelfd); fh->kernelfd = -1; autofs_get_mp(mp); /* Get autofs protocol version */ if (ioctl(fh->ioctlfd, AUTOFS_IOC_PROTOVER, &fh->version) < 0) { plog(XLOG_ERROR, "AUTOFS_IOC_PROTOVER: %s", strerror(errno)); fh->version = AUTOFS_MIN_VERSION; plog(XLOG_ERROR, "autofs: assuming protocol version %d", fh->version); } else plog(XLOG_INFO, "autofs: using protocol version %d", fh->version); /* set expiration timeout */ if (ioctl(fh->ioctlfd, AUTOFS_IOC_SETTIMEOUT, &timeout) < 0) plog(XLOG_ERROR, "AUTOFS_IOC_SETTIMEOUT: %s", strerror(errno)); /* tell the daemon to call us for expirations */ mp->am_autofs_ttl = clocktime(NULL) + gopt.am_timeo_w; } void autofs_get_mp(am_node *mp) { autofs_fh_t *fh = mp->am_autofs_fh; dlog("autofs: getting mount point"); if (fh->ioctlfd < 0) fh->ioctlfd = open(mp->am_path, O_RDONLY); hash_insert(fh->fd, mp); } void autofs_release_mp(am_node *mp) { autofs_fh_t *fh = mp->am_autofs_fh; dlog("autofs: releasing mount point"); if (fh->ioctlfd >= 0) { close(fh->ioctlfd); fh->ioctlfd = -1; } /* * take the kernel fd out of the hash/fdset * so select() doesn't go crazy if the umount succeeds */ if (fh->fd >= 0) hash_delete(fh->fd); } void autofs_release_fh(am_node *mp) { autofs_fh_t *fh = mp->am_autofs_fh; struct autofs_pending_mount **pp, *p; struct autofs_pending_umount **upp, *up; dlog("autofs: releasing file handle"); if (fh) { /* * if a mount succeeded, the kernel fd was closed on * the amd side, so it might have been reused. * we set it to -1 after closing it, to avoid the problem. */ if (fh->kernelfd >= 0) close(fh->kernelfd); if (fh->ioctlfd >= 0) close(fh->ioctlfd); if (fh->fd >= 0) close(fh->fd); pp = &fh->pending_mounts; while (*pp) { p = *pp; XFREE(p->name); *pp = p->next; XFREE(p); } upp = &fh->pending_umounts; while (*upp) { up = *upp; XFREE(up->name); *upp = up->next; XFREE(up); } XFREE(fh); mp->am_autofs_fh = NULL; } } void autofs_add_fdset(fd_set *readfds) { int i; for (i = 0; i < numfds; i++) FD_SET(list[i], readfds); } static ssize_t autofs_get_pkt(int fd, void *buf, size_t bytes) { ssize_t i; do { i = read(fd, buf, bytes); if (i <= 0) break; buf = (char *)buf + i; bytes -= i; } while (bytes); return bytes; } static void send_fail(int fd, autofs_wqt_t token) { if (token == 0) return; if (ioctl(fd, AUTOFS_IOC_FAIL, token) < 0) plog(XLOG_ERROR, "AUTOFS_IOC_FAIL: %s", strerror(errno)); } static void send_ready(int fd, autofs_wqt_t token) { if (token == 0) return; if (ioctl(fd, AUTOFS_IOC_READY, token) < 0) plog(XLOG_ERROR, "AUTOFS_IOC_READY: %s", strerror(errno)); } static void autofs_lookup_failed(am_node *mp, char *name) { autofs_fh_t *fh = mp->am_autofs_fh; struct autofs_pending_mount **pp, *p; pp = &fh->pending_mounts; while (*pp && !STREQ((*pp)->name, name)) pp = &(*pp)->next; /* sanity check */ if (*pp == NULL) return; p = *pp; plog(XLOG_INFO, "autofs: lookup of %s failed", name); send_fail(fh->ioctlfd, p->wait_queue_token); XFREE(p->name); *pp = p->next; XFREE(p); } static void autofs_expire_one(am_node *mp, char *name, autofs_wqt_t token) { autofs_fh_t *fh; am_node *ap; struct autofs_pending_umount *p; char *ap_path; fh = mp->am_autofs_fh; ap_path = str3cat(NULL, mp->am_path, "/", name); if (amuDebug(D_TRACE)) plog(XLOG_DEBUG, "\tumount(%s)", ap_path); p = fh->pending_umounts; while (p && p->wait_queue_token != token) p = p->next; if (p) { /* already pending */ dlog("Umounting of %s already pending", ap_path); amd_stats.d_drops++; goto out; } ap = find_ap(ap_path); if (ap == NULL) { /* not found??? not sure what to do here... */ send_fail(fh->ioctlfd, token); goto out; } p = ALLOC(struct autofs_pending_umount); p->wait_queue_token = token; p->name = xstrdup(name); p->next = fh->pending_umounts; fh->pending_umounts = p; unmount_mp(ap); out: XFREE(ap_path); } static void autofs_missing_one(am_node *mp, autofs_wqt_t wait_queue_token, char *name) { autofs_fh_t *fh; mntfs *mf; am_node *ap; struct autofs_pending_mount *p; int error; mf = mp->am_al->al_mnt; fh = mp->am_autofs_fh; p = fh->pending_mounts; while (p && p->wait_queue_token != wait_queue_token) p = p->next; if (p) { /* already pending */ dlog("Mounting of %s/%s already pending", mp->am_path, name); amd_stats.d_drops++; return; } p = ALLOC(struct autofs_pending_mount); p->wait_queue_token = wait_queue_token; p->name = xstrdup(name); p->next = fh->pending_mounts; fh->pending_mounts = p; if (amuDebug(D_TRACE)) plog(XLOG_DEBUG, "\tlookup(%s, %s)", mp->am_path, name); ap = mf->mf_ops->lookup_child(mp, name, &error, VLOOK_CREATE); if (ap && error < 0) ap = mf->mf_ops->mount_child(ap, &error); /* some of the rest can be done in amfs_auto_cont */ if (ap == 0) { if (error < 0) { dlog("Mount still pending, not sending autofs reply yet"); return; } autofs_lookup_failed(mp, name); } mp->am_stats.s_lookup++; } static void autofs_handle_expire(am_node *mp, struct autofs_packet_expire *pkt) { autofs_expire_one(mp, pkt->name, 0); } static void autofs_handle_missing(am_node *mp, struct autofs_packet_missing *pkt) { autofs_missing_one(mp, pkt->wait_queue_token, pkt->name); } #if AUTOFS_MAX_PROTO_VERSION >= 4 static void autofs_handle_expire_multi(am_node *mp, struct autofs_packet_expire_multi *pkt) { autofs_expire_one(mp, pkt->name, pkt->wait_queue_token); } #endif /* AUTOFS_MAX_PROTO_VERSION >= 4 */ #if AUTOFS_MAX_PROTO_VERSION >= 5 static void autofs_handle_expire_direct(am_node *mp, autofs_packet_expire_direct_t *pkt) { autofs_expire_one(mp, pkt->name, 0); } static void autofs_handle_expire_indirect(am_node *mp, autofs_packet_expire_indirect_t *pkt) { autofs_expire_one(mp, pkt->name, 0); } static void autofs_handle_missing_direct(am_node *mp, autofs_packet_missing_direct_t *pkt) { autofs_missing_one(mp, pkt->wait_queue_token, pkt->name); } static void autofs_handle_missing_indirect(am_node *mp, autofs_packet_missing_indirect_t *pkt) { autofs_missing_one(mp, pkt->wait_queue_token, pkt->name); } #endif /* AUTOFS_MAX_PROTO_VERSION >= 5 */ int autofs_handle_fdset(fd_set *readfds, int nsel) { int i; union { #if AUTOFS_MAX_PROTO_VERSION >= 5 union autofs_v5_packet_union pkt5; #endif union autofs_packet_union pkt; } p; autofs_fh_t *fh; am_node *mp; size_t len; for (i = 0; nsel && i < numfds; i++) { if (!FD_ISSET(list[i], readfds)) continue; nsel--; FD_CLR(list[i], readfds); mp = hash[list[i]]; fh = mp->am_autofs_fh; #if AUTOFS_MAX_PROTO_VERSION >= 5 if (fh->version < 5) { len = sizeof(p.pkt); } else { len = sizeof(p.pkt5); } #else len = sizeof(p.pkt); #endif /* AUTOFS_MAX_PROTO_VERSION >= 5 */ if (autofs_get_pkt(fh->fd, &p, len)) continue; switch (p.pkt.hdr.type) { case autofs_ptype_missing: autofs_handle_missing(mp, &p.pkt.missing); break; case autofs_ptype_expire: autofs_handle_expire(mp, &p.pkt.expire); break; #if AUTOFS_MAX_PROTO_VERSION >= 4 case autofs_ptype_expire_multi: autofs_handle_expire_multi(mp, &p.pkt.expire_multi); break; #endif /* AUTOFS_MAX_PROTO_VERSION >= 4 */ #if AUTOFS_MAX_PROTO_VERSION >= 5 case autofs_ptype_expire_indirect: autofs_handle_expire_indirect(mp, &p.pkt5.expire_direct); break; case autofs_ptype_expire_direct: autofs_handle_expire_direct(mp, &p.pkt5.expire_direct); break; case autofs_ptype_missing_indirect: autofs_handle_missing_indirect(mp, &p.pkt5.missing_direct); break; case autofs_ptype_missing_direct: autofs_handle_missing_direct(mp, &p.pkt5.missing_direct); break; #endif /* AUTOFS_MAX_PROTO_VERSION >= 5 */ default: plog(XLOG_ERROR, "Unknown autofs packet type %d", p.pkt.hdr.type); } } return nsel; } int create_autofs_service(void) { hash_init(); /* not the best place, but... */ if (linux_version_code() < KERNEL_VERSION(2,4,0)) bind_works = 0; return 0; } int destroy_autofs_service(void) { /* Nothing to do */ return 0; } static int autofs_bind_umount(char *mountpoint) { int err = 1; #ifdef MNT2_GEN_OPT_BIND if (bind_works && gopt.flags & CFM_AUTOFS_USE_LOFS) { struct stat buf; if ((err = lstat(mountpoint, &buf))) return errno; if (S_ISLNK(buf.st_mode)) goto use_symlink; plog(XLOG_INFO, "autofs: un-bind-mounting %s", mountpoint); err = umount_fs(mountpoint, mnttab_file_name, 1); if (err) plog(XLOG_INFO, "autofs: unmounting %s failed: %m", mountpoint); else err = rmdir(mountpoint); goto out; } #endif /* MNT2_GEN_OPT_BIND */ use_symlink: plog(XLOG_INFO, "autofs: deleting symlink %s", mountpoint); err = unlink(mountpoint); out: if (err) return errno; return 0; } int autofs_mount_fs(am_node *mp, mntfs *mf) { char *target, *target2 = NULL; int err = 0; if (mf->mf_flags & MFF_ON_AUTOFS) { if ((err = mkdir(mp->am_path, 0555))) return errno; } /* * For sublinks, we could end up here with an already mounted f/s. * Don't do anything in that case. */ if (!(mf->mf_flags & MFF_MOUNTED)) err = mf->mf_ops->mount_fs(mp, mf); if (err) { if (mf->mf_flags & MFF_ON_AUTOFS) rmdir(mp->am_path); return err; } if (mf->mf_flags & MFF_ON_AUTOFS) /* Nothing else to do */ return 0; if (mp->am_link) target = mp->am_link; else target = mf->mf_fo->opt_fs; #ifdef MNT2_GEN_OPT_BIND if (bind_works && gopt.flags & CFM_AUTOFS_USE_LOFS) { struct stat buf; /* * HACK ALERT! * * Since the bind mount mechanism doesn't allow mountpoint crossing, * we _must_ use symlinks for the host mount case. Otherwise we end up * with a bunch of empty mountpoints... */ if (mf->mf_ops == &amfs_host_ops) goto use_symlink; if (target[0] != '/') target2 = str3cat(NULL, mp->am_parent->am_path, "/", target); else target2 = xstrdup(target); /* * We need to stat() the destination, because the bind mount does not * follow symlinks and/or allow for non-existent destinations. * We fall back to symlinks if there are problems. * * We also need to temporarily change pgrp, otherwise our stat() won't * trigger whatever cascading mounts are needed. * * WARNING: we will deadlock if this function is called from the master * amd process and it happens to trigger another auto mount. Therefore, * this function should be called only from a child amd process, or * at the very least it should not be called from the parent unless we * know for sure that it won't cause a recursive mount. We refuse to * cause the recursive mount anyway if called from the parent amd. */ if (!foreground) { pid_t pgrp = getpgrp(); setpgrp(); err = stat(target2, &buf); if ((err = setpgid(0, pgrp))) { plog(XLOG_ERROR, "autofs: cannot restore pgrp: %s", strerror(errno)); plog(XLOG_ERROR, "autofs: aborting the mount"); goto out; } if (err) goto use_symlink; } if ((err = lstat(target2, &buf))) goto use_symlink; if (S_ISLNK(buf.st_mode)) goto use_symlink; plog(XLOG_INFO, "autofs: bind-mounting %s -> %s", mp->am_path, target2); mkdir(mp->am_path, 0555); err = mount_lofs(mp->am_path, target2, mf->mf_mopts, 1); if (err) { rmdir(mp->am_path); plog(XLOG_INFO, "autofs: bind-mounting %s -> %s failed", mp->am_path, target2); goto use_symlink; } goto out; } #endif /* MNT2_GEN_OPT_BIND */ use_symlink: plog(XLOG_INFO, "autofs: symlinking %s -> %s", mp->am_path, target); err = symlink(target, mp->am_path); out: if (target2) XFREE(target2); if (err) return errno; return 0; } int autofs_umount_fs(am_node *mp, mntfs *mf) { int err = 0; if (!(mf->mf_flags & MFF_ON_AUTOFS)) { err = autofs_bind_umount(mp->am_path); if (err) return err; } /* * Multiple sublinks could reference this f/s. * Don't actually unmount it unless we're holding the last reference. */ if (mf->mf_refc == 1) { err = mf->mf_ops->umount_fs(mp, mf); if (err) return err; if (mf->mf_flags & MFF_ON_AUTOFS) rmdir(mp->am_path); } return 0; } int autofs_umount_succeeded(am_node *mp) { autofs_fh_t *fh = mp->am_parent->am_autofs_fh; struct autofs_pending_umount **pp, *p; /* Already gone? */ if (fh == NULL) return 0; pp = &fh->pending_umounts; while (*pp && !STREQ((*pp)->name, mp->am_name)) pp = &(*pp)->next; /* sanity check */ if (*pp == NULL) return -1; p = *pp; plog(XLOG_INFO, "autofs: unmounting %s succeeded", mp->am_path); send_ready(fh->ioctlfd, p->wait_queue_token); XFREE(p->name); *pp = p->next; XFREE(p); return 0; } int autofs_umount_failed(am_node *mp) { autofs_fh_t *fh = mp->am_parent->am_autofs_fh; struct autofs_pending_umount **pp, *p; pp = &fh->pending_umounts; while (*pp && !STREQ((*pp)->name, mp->am_name)) pp = &(*pp)->next; /* sanity check */ if (*pp == NULL) return -1; p = *pp; plog(XLOG_INFO, "autofs: unmounting %s failed", mp->am_path); send_fail(fh->ioctlfd, p->wait_queue_token); XFREE(p->name); *pp = p->next; XFREE(p); return 0; } void autofs_mount_succeeded(am_node *mp) { autofs_fh_t *fh = mp->am_parent->am_autofs_fh; struct autofs_pending_mount **pp, *p; /* * don't expire the entries -- the kernel will do it for us. * * but it won't do autofs filesystems, so we expire them the old * fashioned way instead. */ if (!(mp->am_al->al_mnt->mf_flags & MFF_IS_AUTOFS)) mp->am_flags |= AMF_NOTIMEOUT; pp = &fh->pending_mounts; while (*pp && !STREQ((*pp)->name, mp->am_name)) pp = &(*pp)->next; /* sanity check */ if (*pp == NULL) return; p = *pp; plog(XLOG_INFO, "autofs: mounting %s succeeded", mp->am_path); send_ready(fh->ioctlfd, p->wait_queue_token); XFREE(p->name); *pp = p->next; XFREE(p); } void autofs_mount_failed(am_node *mp) { autofs_fh_t *fh = mp->am_parent->am_autofs_fh; struct autofs_pending_mount **pp, *p; pp = &fh->pending_mounts; while (*pp && !STREQ((*pp)->name, mp->am_name)) pp = &(*pp)->next; /* sanity check */ if (*pp == NULL) return; p = *pp; plog(XLOG_INFO, "autofs: mounting %s failed", mp->am_path); send_fail(fh->ioctlfd, p->wait_queue_token); XFREE(p->name); *pp = p->next; XFREE(p); } void autofs_get_opts(char *opts, size_t l, autofs_fh_t *fh) { xsnprintf(opts, l, "fd=%d,minproto=%d,maxproto=%d", fh->kernelfd, AUTOFS_MIN_VERSION, AUTOFS_MAX_VERSION); } int autofs_compute_mount_flags(mntent_t *mnt) { return 0; } #if AUTOFS_MAX_PROTO_VERSION >= 4 static int autofs_timeout_mp_task(void *arg) { am_node *mp = (am_node *)arg; autofs_fh_t *fh = mp->am_autofs_fh; int now = 0; while (ioctl(fh->ioctlfd, AUTOFS_IOC_EXPIRE_MULTI, &now) == 0); return 0; } #endif /* AUTOFS_MAX_PROTO_VERSION >= 4 */ void autofs_timeout_mp(am_node *mp) { autofs_fh_t *fh = mp->am_autofs_fh; time_t now = clocktime(NULL); /* update the ttl */ mp->am_autofs_ttl = now + gopt.am_timeo_w; if (fh->version < 4) { struct autofs_packet_expire pkt; while (ioctl(fh->ioctlfd, AUTOFS_IOC_EXPIRE, &pkt) == 0) autofs_handle_expire(mp, &pkt); return; } #if AUTOFS_MAX_PROTO_VERSION >= 4 run_task(autofs_timeout_mp_task, mp, NULL, NULL); #endif /* AUTOFS_MAX_PROTO_VERSION >= 4 */ } #endif /* HAVE_FS_AUTOFS */