build fix

1 files changed, 199 insertions, 0 deletions

diff --git a/util/fusermount.c b/util/fusermount.c
new file mode 100644
index 0000000..784fd47
--- /dev/null
+++ b/util/fusermount.c
@@ -0,0 +1,199 @@
+/*
+    FUSE: Filesystem in Userspace
+    Copyright (C) 2001  Miklos Szeredi (mszeredi@inf.bme.hu)
+
+    This program can be distributed under the terms of the GNU GPL.
+    See the file COPYING.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <linux/fuse.h>
+#include <sys/capability.h>
+
+#define FUSE_DEV "/proc/fs/fuse/dev"
+
+const char *progname;
+
+static int do_mount(const char *dev, const char *mnt, const char *type,
+                    mode_t rootmode, int fd)
+{
+    int res;
+    struct fuse_mount_data data;
+    
+    data.version = FUSE_KERNEL_VERSION;
+    data.fd = fd;
+    data.rootmode = rootmode;
+
+    res = mount(dev, mnt, type, MS_MGC_VAL | MS_NOSUID | MS_NODEV, &data);
+    if(res == -1) {
+        fprintf(stderr, "%s: mount failed: %s\n", progname, strerror(errno));
+	return -1;
+    }
+    
+    return 0;
+}
+
+static int check_perm(const char *mnt, struct stat *stbuf)
+{
+    int res;
+   
+    res = lstat(mnt, stbuf);
+    if(res == -1) {
+        fprintf(stderr, "%s: failed to access mountpoint %s: %s\n",
+                progname, mnt, strerror(errno));
+        return -1;
+    }
+
+    if(!S_ISDIR(stbuf->st_mode) && !S_ISREG(stbuf->st_mode)) {
+        fprintf(stderr, "%s: mountpoint %s is a special file\n",
+                progname, mnt);
+        return -1;
+    }
+
+    if(getuid() != 0) {
+        if(stbuf->st_uid != getuid()) {
+            fprintf(stderr, "%s: mountpoint %s not owned by user\n",
+                    progname, mnt);
+            return -1;
+        }
+
+        res = access(mnt, R_OK | W_OK | (S_ISDIR(stbuf->st_mode) ? X_OK : 0));
+        if(res == -1) {
+            fprintf(stderr, "%s: user has no full access to mountpoint %s\n",
+                    progname, mnt);
+            return -1;
+        }
+    }
+    
+    return 0;
+}
+
+static int mount_fuse(const char *mnt)
+{
+    int res;
+    int fd;
+    const char *dev = FUSE_DEV;
+    const char *type = "fuse";
+    struct stat stbuf;
+
+    res = check_perm(mnt, &stbuf);
+    if(res == -1)
+        return -1;
+
+    fd = open(dev, O_RDWR);
+    if(fd == -1) {
+        fprintf(stderr, "%s: unable to open fuse device %s: %s\n", progname,
+                dev, strerror(errno));
+        return -1;
+    }
+ 
+    res = do_mount(dev, mnt, type, stbuf.st_mode & S_IFMT, fd);
+    if(res == -1)
+        return -1;
+
+    return fd;
+}
+
+static void usage()
+{
+    fprintf(stderr,
+            "%s: [options] mountpoint program [args ...]\n"
+            "Options:\n"
+            " -h    print help\n",
+            progname);
+    exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+    int a;
+    const char *mnt = NULL;
+    char **userprog;
+    pid_t pid;
+    int fd;
+    int status;
+    int res;
+
+    progname = argv[0];
+    
+    for(a = 1; a < argc; a++) {
+        if(argv[a][0] != '-')
+            break;
+
+        switch(argv[a][1]) {
+        case 'h':
+            usage();
+            break;
+            
+        default:
+            fprintf(stderr, "%s: Unknown option %s\n", progname, argv[a]);
+            exit(1);
+        }
+    }
+    
+    if(a == argc) {
+        fprintf(stderr, "%s: Missing mountpoint argument\n", progname);
+        exit(1);
+    }
+
+    mnt = argv[a++];
+    
+    if(a == argc) {
+        fprintf(stderr, "%s: Missing program argument\n", progname);
+        exit(1);
+    }
+    
+    userprog = argv + a;
+    
+    fd = mount_fuse(mnt);
+    if(fd == -1)
+        exit(1);
+
+    /* Dup the file descriptor to stdin */
+    if(fd != 0) {
+        dup2(fd, 0);
+        close(fd);
+    }
+    
+    pid = fork();
+    if(pid == -1) {
+        fprintf(stderr, "%s: Unable to fork: %s\n", progname, strerror(errno));
+        umount(mnt);
+        exit(1);
+    }
+    
+    if(pid == 0) {
+        /* Drop setuid/setgid permissions */
+        setuid(getuid());
+        setgid(getgid());
+        
+        execv(userprog[0], userprog);
+        fprintf(stderr, "%s: failed to exec %s: %s\n", progname, userprog[0],
+                strerror(errno));
+        exit(1);
+    }
+
+    close(0);
+    res = waitpid(pid, &status, 0);
+    if(res == -1) {
+        fprintf(stderr, "%s: failed to wait for child: %s\n", progname,
+                strerror(errno));
+        exit(1);
+    }
+    res = umount(mnt);
+    if(res == -1) {
+        fprintf(stderr, "%s: failed to unmount %s: %s\n", progname, mnt,
+                strerror(errno));
+        exit(1);
+    }
+    
+    return 0;
+}