mirror of
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392 lines
8.4 KiB
C
392 lines
8.4 KiB
C
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/*
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FUSE: Filesystem in Userspace
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Copyright (C) 2005-2008 Csaba Henk <csaba.henk@creo.hu>
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This program can be distributed under the terms of the GNU LGPLv2.
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See the file COPYING.LIB.
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*/
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#include "fuse_i.h"
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#include "fuse_misc.h"
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#include "fuse_opt.h"
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <sys/sysctl.h>
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#include <sys/user.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <paths.h>
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#include <limits.h>
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#define FUSERMOUNT_PROG "mount_fusefs"
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#define FUSE_DEV_TRUNK "/dev/fuse"
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enum {
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KEY_ALLOW_ROOT,
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KEY_RO,
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KEY_HELP,
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KEY_VERSION,
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KEY_KERN
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};
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struct mount_opts {
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int allow_other;
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int allow_root;
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int ishelp;
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char *kernel_opts;
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};
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#define FUSE_DUAL_OPT_KEY(templ, key) \
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FUSE_OPT_KEY(templ, key), FUSE_OPT_KEY("no" templ, key)
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static const struct fuse_opt fuse_mount_opts[] = {
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{ "allow_other", offsetof(struct mount_opts, allow_other), 1 },
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{ "allow_root", offsetof(struct mount_opts, allow_root), 1 },
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FUSE_OPT_KEY("allow_root", KEY_ALLOW_ROOT),
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FUSE_OPT_KEY("-r", KEY_RO),
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FUSE_OPT_KEY("-h", KEY_HELP),
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FUSE_OPT_KEY("--help", KEY_HELP),
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FUSE_OPT_KEY("-V", KEY_VERSION),
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FUSE_OPT_KEY("--version", KEY_VERSION),
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/* standard FreeBSD mount options */
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FUSE_DUAL_OPT_KEY("dev", KEY_KERN),
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FUSE_DUAL_OPT_KEY("async", KEY_KERN),
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FUSE_DUAL_OPT_KEY("atime", KEY_KERN),
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FUSE_DUAL_OPT_KEY("dev", KEY_KERN),
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FUSE_DUAL_OPT_KEY("exec", KEY_KERN),
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FUSE_DUAL_OPT_KEY("suid", KEY_KERN),
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FUSE_DUAL_OPT_KEY("symfollow", KEY_KERN),
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FUSE_DUAL_OPT_KEY("rdonly", KEY_KERN),
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FUSE_DUAL_OPT_KEY("sync", KEY_KERN),
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FUSE_DUAL_OPT_KEY("union", KEY_KERN),
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FUSE_DUAL_OPT_KEY("userquota", KEY_KERN),
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FUSE_DUAL_OPT_KEY("groupquota", KEY_KERN),
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FUSE_DUAL_OPT_KEY("clusterr", KEY_KERN),
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FUSE_DUAL_OPT_KEY("clusterw", KEY_KERN),
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FUSE_DUAL_OPT_KEY("suiddir", KEY_KERN),
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FUSE_DUAL_OPT_KEY("snapshot", KEY_KERN),
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FUSE_DUAL_OPT_KEY("multilabel", KEY_KERN),
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FUSE_DUAL_OPT_KEY("acls", KEY_KERN),
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FUSE_DUAL_OPT_KEY("force", KEY_KERN),
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FUSE_DUAL_OPT_KEY("update", KEY_KERN),
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FUSE_DUAL_OPT_KEY("ro", KEY_KERN),
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FUSE_DUAL_OPT_KEY("rw", KEY_KERN),
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FUSE_DUAL_OPT_KEY("auto", KEY_KERN),
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/* options supported under both Linux and FBSD */
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FUSE_DUAL_OPT_KEY("allow_other", KEY_KERN),
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FUSE_DUAL_OPT_KEY("default_permissions",KEY_KERN),
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FUSE_OPT_KEY("max_read=", KEY_KERN),
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FUSE_OPT_KEY("subtype=", KEY_KERN),
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/* FBSD FUSE specific mount options */
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FUSE_DUAL_OPT_KEY("private", KEY_KERN),
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FUSE_DUAL_OPT_KEY("neglect_shares", KEY_KERN),
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FUSE_DUAL_OPT_KEY("push_symlinks_in", KEY_KERN),
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FUSE_OPT_KEY("nosync_unmount", KEY_KERN),
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/* stock FBSD mountopt parsing routine lets anything be negated... */
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/*
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* Linux specific mount options, but let just the mount util
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* handle them
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*/
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FUSE_OPT_KEY("fsname=", KEY_KERN),
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FUSE_OPT_KEY("nonempty", KEY_KERN),
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FUSE_OPT_KEY("large_read", KEY_KERN),
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FUSE_OPT_END
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};
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static void mount_help(void)
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{
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fprintf(stderr,
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" -o allow_root allow access to root\n"
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);
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system(FUSERMOUNT_PROG " --help");
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fputc('\n', stderr);
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}
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static void mount_version(void)
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{
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system(FUSERMOUNT_PROG " --version");
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}
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static int fuse_mount_opt_proc(void *data, const char *arg, int key,
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struct fuse_args *outargs)
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{
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struct mount_opts *mo = data;
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switch (key) {
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case KEY_ALLOW_ROOT:
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if (fuse_opt_add_opt(&mo->kernel_opts, "allow_other") == -1 ||
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fuse_opt_add_arg(outargs, "-oallow_root") == -1)
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return -1;
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return 0;
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case KEY_RO:
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arg = "ro";
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/* fall through */
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case KEY_KERN:
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return fuse_opt_add_opt(&mo->kernel_opts, arg);
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case KEY_HELP:
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mount_help();
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mo->ishelp = 1;
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break;
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case KEY_VERSION:
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mount_version();
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mo->ishelp = 1;
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break;
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}
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return 1;
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}
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void fuse_unmount_compat22(const char *mountpoint)
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{
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char dev[128];
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char *ssc, *umount_cmd;
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FILE *sf;
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int rv;
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char seekscript[] =
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/* error message is annoying in help output */
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"exec 2>/dev/null; "
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"/usr/bin/fstat " FUSE_DEV_TRUNK "* | "
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"/usr/bin/awk 'BEGIN{ getline; if (! ($3 == \"PID\" && $10 == \"NAME\")) exit 1; }; "
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" { if ($3 == %d) print $10; }' | "
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"/usr/bin/sort | "
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"/usr/bin/uniq | "
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"/usr/bin/awk '{ i += 1; if (i > 1){ exit 1; }; printf; }; END{ if (i == 0) exit 1; }'";
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(void) mountpoint;
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/*
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* If we don't know the fd, we have to resort to the scripted
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* solution -- iterating over the fd-s is unpractical, as we
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* don't know how many of open files we have. (This could be
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* looked up in procfs -- however, that's optional on FBSD; or
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* read out from the kmem -- however, that's bound to
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* privileges (in fact, that's what happens when we call the
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* setgid kmem fstat(1) utility).
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*/
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if (asprintf(&ssc, seekscript, getpid()) == -1)
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return;
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errno = 0;
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sf = popen(ssc, "r");
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free(ssc);
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if (! sf)
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return;
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fgets(dev, sizeof(dev), sf);
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rv = pclose(sf);
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if (rv)
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return;
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if (asprintf(&umount_cmd, "/sbin/umount %s", dev) == -1)
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return;
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system(umount_cmd);
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free(umount_cmd);
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}
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static void do_unmount(char *dev, int fd)
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{
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char device_path[SPECNAMELEN + 12];
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const char *argv[4];
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const char umount_cmd[] = "/sbin/umount";
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pid_t pid;
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snprintf(device_path, SPECNAMELEN + 12, _PATH_DEV "%s", dev);
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argv[0] = umount_cmd;
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argv[1] = "-f";
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argv[2] = device_path;
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argv[3] = NULL;
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pid = fork();
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if (pid == -1)
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return;
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if (pid == 0) {
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close(fd);
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execvp(umount_cmd, (char **)argv);
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exit(1);
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}
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waitpid(pid, NULL, 0);
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}
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void fuse_kern_unmount(const char *mountpoint, int fd)
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{
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char *ep, dev[128];
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struct stat sbuf;
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(void)mountpoint;
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if (fstat(fd, &sbuf) == -1)
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goto out;
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devname_r(sbuf.st_rdev, S_IFCHR, dev, 128);
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if (strncmp(dev, "fuse", 4))
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goto out;
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strtol(dev + 4, &ep, 10);
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if (*ep != '\0')
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goto out;
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do_unmount(dev, fd);
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out:
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close(fd);
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}
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/* Check if kernel is doing init in background */
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static int init_backgrounded(void)
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{
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unsigned ibg, len;
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len = sizeof(ibg);
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if (sysctlbyname("vfs.fuse.init_backgrounded", &ibg, &len, NULL, 0))
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return 0;
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return ibg;
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}
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static int fuse_mount_core(const char *mountpoint, const char *opts)
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{
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const char *mountprog = FUSERMOUNT_PROG;
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int fd;
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char *fdnam, *dev;
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pid_t pid, cpid;
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int status;
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fdnam = getenv("FUSE_DEV_FD");
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if (fdnam) {
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char *ep;
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fd = strtol(fdnam, &ep, 10);
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if (*ep != '\0') {
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fprintf(stderr, "invalid value given in FUSE_DEV_FD\n");
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return -1;
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}
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if (fd < 0)
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return -1;
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goto mount;
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}
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dev = getenv("FUSE_DEV_NAME");
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if (! dev)
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dev = (char *)FUSE_DEV_TRUNK;
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if ((fd = open(dev, O_RDWR)) < 0) {
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perror("fuse: failed to open fuse device");
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return -1;
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}
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mount:
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if (getenv("FUSE_NO_MOUNT") || ! mountpoint)
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goto out;
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pid = fork();
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cpid = pid;
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if (pid == -1) {
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perror("fuse: fork() failed");
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close(fd);
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return -1;
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}
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if (pid == 0) {
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if (! init_backgrounded()) {
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/*
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* If init is not backgrounded, we have to
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* call the mount util backgrounded, to avoid
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* deadlock.
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*/
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pid = fork();
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if (pid == -1) {
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perror("fuse: fork() failed");
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close(fd);
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exit(1);
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}
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}
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if (pid == 0) {
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const char *argv[32];
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int a = 0;
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if (! fdnam && asprintf(&fdnam, "%d", fd) == -1) {
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perror("fuse: failed to assemble mount arguments");
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exit(1);
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}
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argv[a++] = mountprog;
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if (opts) {
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argv[a++] = "-o";
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argv[a++] = opts;
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}
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argv[a++] = fdnam;
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argv[a++] = mountpoint;
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argv[a++] = NULL;
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execvp(mountprog, (char **) argv);
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perror("fuse: failed to exec mount program");
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exit(1);
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}
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exit(0);
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}
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if (waitpid(cpid, &status, 0) == -1 || WEXITSTATUS(status) != 0) {
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perror("fuse: failed to mount file system");
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close(fd);
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return -1;
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}
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out:
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return fd;
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}
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int fuse_kern_mount(const char *mountpoint, struct fuse_args *args)
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{
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struct mount_opts mo;
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int res = -1;
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memset(&mo, 0, sizeof(mo));
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/* mount util should not try to spawn the daemon */
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setenv("MOUNT_FUSEFS_SAFE", "1", 1);
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/* to notify the mount util it's called from lib */
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setenv("MOUNT_FUSEFS_CALL_BY_LIB", "1", 1);
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if (args &&
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fuse_opt_parse(args, &mo, fuse_mount_opts, fuse_mount_opt_proc) == -1)
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return -1;
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if (mo.allow_other && mo.allow_root) {
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fprintf(stderr, "fuse: 'allow_other' and 'allow_root' options are mutually exclusive\n");
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goto out;
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}
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if (mo.ishelp)
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return 0;
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res = fuse_mount_core(mountpoint, mo.kernel_opts);
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out:
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free(mo.kernel_opts);
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return res;
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}
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FUSE_SYMVER(".symver fuse_unmount_compat22,fuse_unmount@FUSE_2.2");
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