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-rw-r--r--fuse/mount.c596
1 files changed, 596 insertions, 0 deletions
diff --git a/fuse/mount.c b/fuse/mount.c
new file mode 100644
index 000000000..88ab59721
--- /dev/null
+++ b/fuse/mount.c
@@ -0,0 +1,596 @@
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU LGPLv2.
+ See the file COPYING.LIB.
+*/
+
+#include "config.h"
+#include "fuse_i.h"
+#include "fuse_misc.h"
+#include "fuse_opt.h"
+#include "fuse_common_compat.h"
+#include "mount_util.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/poll.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <sys/mount.h>
+
+#define FUSERMOUNT_PROG "fusermount"
+#define FUSE_COMMFD_ENV "_FUSE_COMMFD"
+
+#ifndef HAVE_FORK
+#define fork() vfork()
+#endif
+
+#ifndef MS_DIRSYNC
+#define MS_DIRSYNC 128
+#endif
+
+enum {
+ KEY_KERN_FLAG,
+ KEY_KERN_OPT,
+ KEY_FUSERMOUNT_OPT,
+ KEY_SUBTYPE_OPT,
+ KEY_MTAB_OPT,
+ KEY_ALLOW_ROOT,
+ KEY_RO,
+ KEY_HELP,
+ KEY_VERSION,
+};
+
+struct mount_opts {
+ int allow_other;
+ int allow_root;
+ int ishelp;
+ int flags;
+ int nonempty;
+ int blkdev;
+ char *fsname;
+ char *subtype;
+ char *subtype_opt;
+ char *mtab_opts;
+ char *fusermount_opts;
+ char *kernel_opts;
+};
+
+#define FUSE_MOUNT_OPT(t, p) { t, offsetof(struct mount_opts, p), 1 }
+
+static const struct fuse_opt fuse_mount_opts[] = {
+ FUSE_MOUNT_OPT("allow_other", allow_other),
+ FUSE_MOUNT_OPT("allow_root", allow_root),
+ FUSE_MOUNT_OPT("nonempty", nonempty),
+ FUSE_MOUNT_OPT("blkdev", blkdev),
+ FUSE_MOUNT_OPT("fsname=%s", fsname),
+ FUSE_MOUNT_OPT("subtype=%s", subtype),
+ FUSE_OPT_KEY("allow_other", KEY_KERN_OPT),
+ FUSE_OPT_KEY("allow_root", KEY_ALLOW_ROOT),
+ FUSE_OPT_KEY("nonempty", KEY_FUSERMOUNT_OPT),
+ FUSE_OPT_KEY("blkdev", KEY_FUSERMOUNT_OPT),
+ FUSE_OPT_KEY("fsname=", KEY_FUSERMOUNT_OPT),
+ FUSE_OPT_KEY("subtype=", KEY_SUBTYPE_OPT),
+ FUSE_OPT_KEY("large_read", KEY_KERN_OPT),
+ FUSE_OPT_KEY("blksize=", KEY_KERN_OPT),
+ FUSE_OPT_KEY("default_permissions", KEY_KERN_OPT),
+ FUSE_OPT_KEY("max_read=", KEY_KERN_OPT),
+ FUSE_OPT_KEY("max_read=", FUSE_OPT_KEY_KEEP),
+ FUSE_OPT_KEY("user=", KEY_MTAB_OPT),
+ FUSE_OPT_KEY("-r", KEY_RO),
+ FUSE_OPT_KEY("ro", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("rw", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("suid", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("nosuid", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("dev", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("nodev", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("exec", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("noexec", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("async", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("sync", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("dirsync", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("atime", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("noatime", KEY_KERN_FLAG),
+ FUSE_OPT_KEY("-h", KEY_HELP),
+ FUSE_OPT_KEY("--help", KEY_HELP),
+ FUSE_OPT_KEY("-V", KEY_VERSION),
+ FUSE_OPT_KEY("--version", KEY_VERSION),
+ FUSE_OPT_END
+};
+
+static void mount_help(void)
+{
+ fprintf(stderr,
+" -o allow_other allow access to other users\n"
+" -o allow_root allow access to root\n"
+" -o nonempty allow mounts over non-empty file/dir\n"
+" -o default_permissions enable permission checking by kernel\n"
+" -o fsname=NAME set filesystem name\n"
+" -o subtype=NAME set filesystem type\n"
+" -o large_read issue large read requests (2.4 only)\n"
+" -o max_read=N set maximum size of read requests\n"
+"\n");
+}
+
+#define FUSERMOUNT_DIR "/usr/bin"
+
+static void exec_fusermount(const char *argv[])
+{
+ execv(FUSERMOUNT_DIR "/" FUSERMOUNT_PROG, (char **) argv);
+ execvp(FUSERMOUNT_PROG, (char **) argv);
+}
+
+static void mount_version(void)
+{
+ int pid = fork();
+ if (!pid) {
+ const char *argv[] = { FUSERMOUNT_PROG, "--version", NULL };
+ exec_fusermount(argv);
+ _exit(1);
+ } else if (pid != -1)
+ waitpid(pid, NULL, 0);
+}
+
+struct mount_flags {
+ const char *opt;
+ unsigned long flag;
+ int on;
+};
+
+static struct mount_flags mount_flags[] = {
+ {"rw", MS_RDONLY, 0},
+ {"ro", MS_RDONLY, 1},
+ {"suid", MS_NOSUID, 0},
+ {"nosuid", MS_NOSUID, 1},
+ {"dev", MS_NODEV, 0},
+ {"nodev", MS_NODEV, 1},
+ {"exec", MS_NOEXEC, 0},
+ {"noexec", MS_NOEXEC, 1},
+ {"async", MS_SYNCHRONOUS, 0},
+ {"sync", MS_SYNCHRONOUS, 1},
+ {"atime", MS_NOATIME, 0},
+ {"noatime", MS_NOATIME, 1},
+ {"dirsync", MS_DIRSYNC, 1},
+ {NULL, 0, 0}
+};
+
+static void set_mount_flag(const char *s, int *flags)
+{
+ int i;
+
+ for (i = 0; mount_flags[i].opt != NULL; i++) {
+ const char *opt = mount_flags[i].opt;
+ if (strcmp(opt, s) == 0) {
+ if (mount_flags[i].on)
+ *flags |= mount_flags[i].flag;
+ else
+ *flags &= ~mount_flags[i].flag;
+ return;
+ }
+ }
+ fprintf(stderr, "fuse: internal error, can't find mount flag\n");
+ abort();
+}
+
+static int fuse_mount_opt_proc(void *data, const char *arg, int key,
+ struct fuse_args *outargs)
+{
+ struct mount_opts *mo = data;
+
+ switch (key) {
+ case KEY_ALLOW_ROOT:
+ if (fuse_opt_add_opt(&mo->kernel_opts, "allow_other") == -1 ||
+ fuse_opt_add_arg(outargs, "-oallow_root") == -1)
+ return -1;
+ return 0;
+
+ case KEY_RO:
+ arg = "ro";
+ /* fall through */
+ case KEY_KERN_FLAG:
+ set_mount_flag(arg, &mo->flags);
+ return 0;
+
+ case KEY_KERN_OPT:
+ return fuse_opt_add_opt(&mo->kernel_opts, arg);
+
+ case KEY_FUSERMOUNT_OPT:
+ return fuse_opt_add_opt_escaped(&mo->fusermount_opts, arg);
+
+ case KEY_SUBTYPE_OPT:
+ return fuse_opt_add_opt(&mo->subtype_opt, arg);
+
+ case KEY_MTAB_OPT:
+ return fuse_opt_add_opt(&mo->mtab_opts, arg);
+
+ case KEY_HELP:
+ mount_help();
+ mo->ishelp = 1;
+ break;
+
+ case KEY_VERSION:
+ mount_version();
+ mo->ishelp = 1;
+ break;
+ }
+ return 1;
+}
+
+/* return value:
+ * >= 0 => fd
+ * -1 => error
+ */
+static int receive_fd(int fd)
+{
+ struct msghdr msg;
+ struct iovec iov;
+ char buf[1];
+ int rv;
+ size_t ccmsg[CMSG_SPACE(sizeof(int)) / sizeof(size_t)];
+ struct cmsghdr *cmsg;
+
+ iov.iov_base = buf;
+ iov.iov_len = 1;
+
+ msg.msg_name = 0;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ /* old BSD implementations should use msg_accrights instead of
+ * msg_control; the interface is different. */
+ msg.msg_control = ccmsg;
+ msg.msg_controllen = sizeof(ccmsg);
+
+ while(((rv = recvmsg(fd, &msg, 0)) == -1) && errno == EINTR);
+ if (rv == -1) {
+ perror("recvmsg");
+ return -1;
+ }
+ if(!rv) {
+ /* EOF */
+ return -1;
+ }
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg->cmsg_type == SCM_RIGHTS) {
+ fprintf(stderr, "got control message of unknown type %d\n",
+ cmsg->cmsg_type);
+ return -1;
+ }
+ return *(int*)CMSG_DATA(cmsg);
+}
+
+void fuse_kern_unmount(const char *mountpoint, int fd)
+{
+ int res;
+ int pid;
+
+ if (!mountpoint)
+ return;
+
+ if (fd != -1) {
+ struct pollfd pfd;
+
+ pfd.fd = fd;
+ pfd.events = 0;
+ res = poll(&pfd, 1, 0);
+ /* If file poll returns POLLERR on the device file descriptor,
+ then the filesystem is already unmounted */
+ if (res == 1 && (pfd.revents & POLLERR))
+ return;
+
+ /* Need to close file descriptor, otherwise synchronous umount
+ would recurse into filesystem, and deadlock */
+ close(fd);
+ }
+
+ if (geteuid() == 0) {
+ fuse_mnt_umount("fuse", mountpoint, mountpoint, 1);
+ return;
+ }
+
+ res = umount2(mountpoint, 2);
+ if (res == 0)
+ return;
+
+ pid = fork();
+ if(pid == -1)
+ return;
+
+ if(pid == 0) {
+ const char *argv[] = { FUSERMOUNT_PROG, "-u", "-q", "-z",
+ "--", mountpoint, NULL };
+
+ exec_fusermount(argv);
+ _exit(1);
+ }
+ waitpid(pid, NULL, 0);
+}
+
+void fuse_unmount_compat22(const char *mountpoint)
+{
+ fuse_kern_unmount(mountpoint, -1);
+}
+
+static int fuse_mount_fusermount(const char *mountpoint, const char *opts,
+ int quiet)
+{
+ int fds[2], pid;
+ int res;
+ int rv;
+
+ if (!mountpoint) {
+ fprintf(stderr, "fuse: missing mountpoint parameter\n");
+ return -1;
+ }
+
+ res = socketpair(PF_UNIX, SOCK_STREAM, 0, fds);
+ if(res == -1) {
+ perror("fuse: socketpair() failed");
+ return -1;
+ }
+
+ pid = fork();
+ if(pid == -1) {
+ perror("fuse: fork() failed");
+ close(fds[0]);
+ close(fds[1]);
+ return -1;
+ }
+
+ if(pid == 0) {
+ char env[10];
+ const char *argv[32];
+ int a = 0;
+
+ if (quiet) {
+ int fd = open("/dev/null", O_RDONLY);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ }
+
+ argv[a++] = FUSERMOUNT_PROG;
+ if (opts) {
+ argv[a++] = "-o";
+ argv[a++] = opts;
+ }
+ argv[a++] = "--";
+ argv[a++] = mountpoint;
+ argv[a++] = NULL;
+
+ close(fds[1]);
+ fcntl(fds[0], F_SETFD, 0);
+ snprintf(env, sizeof(env), "%i", fds[0]);
+ setenv(FUSE_COMMFD_ENV, env, 1);
+ exec_fusermount(argv);
+ perror("fuse: failed to exec fusermount");
+ _exit(1);
+ }
+
+ close(fds[0]);
+ rv = receive_fd(fds[1]);
+ close(fds[1]);
+ waitpid(pid, NULL, 0); /* bury zombie */
+
+ return rv;
+}
+
+int fuse_mount_compat22(const char *mountpoint, const char *opts)
+{
+ return fuse_mount_fusermount(mountpoint, opts, 0);
+}
+
+static int fuse_mount_sys(const char *mnt, struct mount_opts *mo,
+ const char *mnt_opts)
+{
+ char tmp[128];
+ const char *devname = "/dev/fuse";
+ char *source = NULL;
+ char *type = NULL;
+ struct stat stbuf;
+ int fd;
+ int res;
+
+ if (!mnt) {
+ fprintf(stderr, "fuse: missing mountpoint parameter\n");
+ return -1;
+ }
+
+ res = stat(mnt, &stbuf);
+ if (res == -1) {
+ fprintf(stderr ,"fuse: failed to access mountpoint %s: %s\n",
+ mnt, strerror(errno));
+ return -1;
+ }
+
+ if (!mo->nonempty) {
+ res = fuse_mnt_check_empty("fuse", mnt, stbuf.st_mode,
+ stbuf.st_size);
+ if (res == -1)
+ return -1;
+ }
+
+ fd = open(devname, O_RDWR);
+ if (fd == -1) {
+ if (errno == ENODEV || errno == ENOENT)
+ fprintf(stderr, "fuse: device not found, try 'modprobe fuse' first\n");
+ else
+ fprintf(stderr, "fuse: failed to open %s: %s\n",
+ devname, strerror(errno));
+ return -1;
+ }
+
+ snprintf(tmp, sizeof(tmp), "fd=%i,rootmode=%o,user_id=%i,group_id=%i",
+ fd, stbuf.st_mode & S_IFMT, getuid(), getgid());
+
+ res = fuse_opt_add_opt(&mo->kernel_opts, tmp);
+ if (res == -1)
+ goto out_close;
+
+ source = malloc((mo->fsname ? strlen(mo->fsname) : 0) +
+ (mo->subtype ? strlen(mo->subtype) : 0) +
+ strlen(devname) + 32);
+
+ type = malloc((mo->subtype ? strlen(mo->subtype) : 0) + 32);
+ if (!type || !source) {
+ fprintf(stderr, "fuse: failed to allocate memory\n");
+ goto out_close;
+ }
+
+ strcpy(type, mo->blkdev ? "fuseblk" : "fuse");
+ if (mo->subtype) {
+ strcat(type, ".");
+ strcat(type, mo->subtype);
+ }
+ strcpy(source,
+ mo->fsname ? mo->fsname : (mo->subtype ? mo->subtype : devname));
+
+ res = mount(source, mnt, type, mo->flags, mo->kernel_opts);
+ if (res == -1 && errno == ENODEV && mo->subtype) {
+ /* Probably missing subtype support */
+ strcpy(type, mo->blkdev ? "fuseblk" : "fuse");
+ if (mo->fsname) {
+ if (!mo->blkdev)
+ sprintf(source, "%s#%s", mo->subtype,
+ mo->fsname);
+ } else {
+ strcpy(source, type);
+ }
+ res = mount(source, mnt, type, mo->flags, mo->kernel_opts);
+ }
+ if (res == -1) {
+ /*
+ * Maybe kernel doesn't support unprivileged mounts, in this
+ * case try falling back to fusermount
+ */
+ if (errno == EPERM) {
+ res = -2;
+ } else {
+ int errno_save = errno;
+ if (mo->blkdev && errno == ENODEV &&
+ !fuse_mnt_check_fuseblk())
+ fprintf(stderr,
+ "fuse: 'fuseblk' support missing\n");
+ else
+ fprintf(stderr, "fuse: mount failed: %s\n",
+ strerror(errno_save));
+ }
+
+ goto out_close;
+ }
+
+ if (geteuid() == 0) {
+ char *newmnt = fuse_mnt_resolve_path("fuse", mnt);
+ res = -1;
+ if (!newmnt)
+ goto out_umount;
+
+ res = fuse_mnt_add_mount("fuse", source, newmnt, type,
+ mnt_opts);
+ free(newmnt);
+ if (res == -1)
+ goto out_umount;
+ }
+ free(type);
+ free(source);
+
+ return fd;
+
+out_umount:
+ umount2(mnt, 2); /* lazy umount */
+out_close:
+ free(type);
+ free(source);
+ close(fd);
+ return res;
+}
+
+static int get_mnt_flag_opts(char **mnt_optsp, int flags)
+{
+ int i;
+
+ if (!(flags & MS_RDONLY) && fuse_opt_add_opt(mnt_optsp, "rw") == -1)
+ return -1;
+
+ for (i = 0; mount_flags[i].opt != NULL; i++) {
+ if (mount_flags[i].on && (flags & mount_flags[i].flag) &&
+ fuse_opt_add_opt(mnt_optsp, mount_flags[i].opt) == -1)
+ return -1;
+ }
+ return 0;
+}
+
+int fuse_kern_mount(const char *mountpoint, struct fuse_args *args)
+{
+ struct mount_opts mo;
+ int res = -1;
+ char *mnt_opts = NULL;
+
+ memset(&mo, 0, sizeof(mo));
+ mo.flags = MS_NOSUID | MS_NODEV;
+
+ if (args &&
+ fuse_opt_parse(args, &mo, fuse_mount_opts, fuse_mount_opt_proc) == -1)
+ return -1;
+
+ if (mo.allow_other && mo.allow_root) {
+ fprintf(stderr, "fuse: 'allow_other' and 'allow_root' options are mutually exclusive\n");
+ goto out;
+ }
+ res = 0;
+ if (mo.ishelp)
+ goto out;
+
+ res = -1;
+ if (get_mnt_flag_opts(&mnt_opts, mo.flags) == -1)
+ goto out;
+ if (mo.kernel_opts && fuse_opt_add_opt(&mnt_opts, mo.kernel_opts) == -1)
+ goto out;
+ if (mo.mtab_opts && fuse_opt_add_opt(&mnt_opts, mo.mtab_opts) == -1)
+ goto out;
+
+ res = fuse_mount_sys(mountpoint, &mo, mnt_opts);
+ if (res == -2) {
+ if (mo.fusermount_opts &&
+ fuse_opt_add_opt(&mnt_opts, mo.fusermount_opts) == -1)
+ goto out;
+
+ if (mo.subtype) {
+ char *tmp_opts = NULL;
+
+ res = -1;
+ if (fuse_opt_add_opt(&tmp_opts, mnt_opts) == -1 ||
+ fuse_opt_add_opt(&tmp_opts, mo.subtype_opt) == -1) {
+ free(tmp_opts);
+ goto out;
+ }
+
+ res = fuse_mount_fusermount(mountpoint, tmp_opts, 1);
+ free(tmp_opts);
+ if (res == -1)
+ res = fuse_mount_fusermount(mountpoint,
+ mnt_opts, 0);
+ } else {
+ res = fuse_mount_fusermount(mountpoint, mnt_opts, 0);
+ }
+ }
+out:
+ free(mnt_opts);
+ free(mo.fsname);
+ free(mo.subtype);
+ free(mo.fusermount_opts);
+ free(mo.subtype_opt);
+ free(mo.kernel_opts);
+ free(mo.mtab_opts);
+ return res;
+}
+
+FUSE_SYMVER(".symver fuse_mount_compat22,fuse_mount@FUSE_2.2");
+FUSE_SYMVER(".symver fuse_unmount_compat22,fuse_unmount@FUSE_2.2");
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 07:12:00 +0100