cvs/lib/mount.c

/*
    FUSE: Filesystem in Userspace
    Copyright (C) 2001-2004  Miklos Szeredi <miklos@szeredi.hu>

    This program can be distributed under the terms of the GNU LGPL.
    See the file COPYING.LIB.
*/

#include "fuse.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>

#define FUSERMOUNT_PROG         "fusermount"
#define FUSE_COMMFD_ENV         "_FUSE_COMMFD"


/* return value:
 * >= 0  => fd
 * -1    => error
 */
static int receive_fd(int fd)
{
    struct msghdr msg;
    struct iovec iov;
    char buf[1];
    int rv;
    int connfd = -1;
    char ccmsg[CMSG_SPACE(sizeof(connfd))];
    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_unmount(const char *mountpoint)
{
    const char *mountprog = FUSERMOUNT_PROG;
    char umount_cmd[1024];
    
    snprintf(umount_cmd, sizeof(umount_cmd) - 1, "%s -u -q -z %s", mountprog,
             mountpoint);
    
    umount_cmd[sizeof(umount_cmd) - 1] = '\0';
    system(umount_cmd);
}

int fuse_mount(const char *mountpoint, const char *opts)
{
    const char *mountprog = FUSERMOUNT_PROG;
    int fds[2], pid;
    int res;
    int rv;

    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[] = {mountprog, opts ? "-o" : mountpoint, opts,
                              mountpoint, NULL};

        close(fds[1]);
        fcntl(fds[0], F_SETFD, 0);
        snprintf(env, sizeof(env), "%i", fds[0]);
        setenv(FUSE_COMMFD_ENV, env, 1);
        execvp(mountprog, (char **) 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;
}
1	/*
2	FUSE: Filesystem in Userspace
3	Copyright (C) 2001-2004 Miklos Szeredi <miklos@szeredi.hu>
4
5	This program can be distributed under the terms of the GNU LGPL.
6	See the file COPYING.LIB.
7	*/
8
9	#include "fuse.h"
10
11	#include <stdio.h>
12	#include <stdlib.h>
13	#include <unistd.h>
14	#include <fcntl.h>
15	#include <errno.h>
16	#include <sys/socket.h>
17	#include <sys/un.h>
18	#include <sys/wait.h>
19
20	#define FUSERMOUNT_PROG "fusermount"
21	#define FUSE_COMMFD_ENV "_FUSE_COMMFD"
22
23
24	/* return value:
25	* >= 0 => fd
26	* -1 => error
27	*/
28	static int receive_fd(int fd)
29	{
30	struct msghdr msg;
31	struct iovec iov;
32	char buf[1];
33	int rv;
34	int connfd = -1;
35	char ccmsg[CMSG_SPACE(sizeof(connfd))];
36	struct cmsghdr *cmsg;
37
38	iov.iov_base = buf;
39	iov.iov_len = 1;
40
41	msg.msg_name = 0;
42	msg.msg_namelen = 0;
43	msg.msg_iov = &iov;
44	msg.msg_iovlen = 1;
45	/* old BSD implementations should use msg_accrights instead of
46	* msg_control; the interface is different. */
47	msg.msg_control = ccmsg;
48	msg.msg_controllen = sizeof(ccmsg);
49
50	while(((rv = recvmsg(fd, &msg, 0)) == -1) && errno == EINTR);
51	if (rv == -1) {
52	perror("recvmsg");
53	return -1;
54	}
55	if(!rv) {
56	/* EOF */
57	return -1;
58	}
59
60	cmsg = CMSG_FIRSTHDR(&msg);
61	if (!cmsg->cmsg_type == SCM_RIGHTS) {
62	fprintf(stderr, "got control message of unknown type %d\n",
63	cmsg->cmsg_type);
64	return -1;
65	}
66	return (int)CMSG_DATA(cmsg);
67	}
68
69	void fuse_unmount(const char *mountpoint)
70	{
71	const char *mountprog = FUSERMOUNT_PROG;
72	char umount_cmd[1024];
73
74	snprintf(umount_cmd, sizeof(umount_cmd) - 1, "%s -u -q -z %s", mountprog,
75	mountpoint);
76
77	umount_cmd[sizeof(umount_cmd) - 1] = '\0';
78	system(umount_cmd);
79	}
80
81	int fuse_mount(const char mountpoint, const char opts)
82	{
83	const char *mountprog = FUSERMOUNT_PROG;
84	int fds[2], pid;
85	int res;
86	int rv;
87
88	res = socketpair(PF_UNIX, SOCK_STREAM, 0, fds);
89	if(res == -1) {
90	perror("fuse: socketpair() failed");
91	return -1;
92	}
93
94	pid = fork();
95	if(pid == -1) {
96	perror("fuse: fork() failed");
97	close(fds[0]);
98	close(fds[1]);
99	return -1;
100	}
101
102	if(pid == 0) {
103	char env[10];
104	const char *argv[] = {mountprog, opts ? "-o" : mountpoint, opts,
105	mountpoint, NULL};
106
107	close(fds[1]);
108	fcntl(fds[0], F_SETFD, 0);
109	snprintf(env, sizeof(env), "%i", fds[0]);
110	setenv(FUSE_COMMFD_ENV, env, 1);
111	execvp(mountprog, (char **) argv);
112	perror("fuse: failed to exec fusermount");
113	exit(1);
114	}
115
116	close(fds[0]);
117	rv = receive_fd(fds[1]);
118	close(fds[1]);
119	waitpid(pid, NULL, 0); /* bury zombie */
120
121	return rv;
122	}