fuse_mount_ioslave() and helper util

3 files changed, 60 insertions, 1 deletions

diff --git a/util/.cvsignore b/util/.cvsignore
index 5f7d28d..ab2dc89 100644
--- a/util/.cvsignore
+++ b/util/.cvsignore
@@ -2,3 +2,4 @@ Makefile.in
 Makefile
 .deps
 fusermount
+fuse_ioslave
diff --git a/util/Makefile.am b/util/Makefile.am
index 48f9957..0e4434f 100644
--- a/util/Makefile.am
+++ b/util/Makefile.am
@@ -1,8 +1,9 @@
 ## Process this file with automake to produce Makefile.in
 
-bin_PROGRAMS = fusermount
+bin_PROGRAMS = fusermount fuse_ioslave
 
 fusermount_SOURCES = fusermount.c
+fuse_ioslave_SOURCES = fuse_ioslave.c
 
 install-exec-hook:
 	-chown root $(DESTDIR)$(bindir)/fusermount
diff --git a/util/fuse_ioslave.c b/util/fuse_ioslave.c
new file mode 100644
index 0000000..1fa3bbf
--- /dev/null
+++ b/util/fuse_ioslave.c
@@ -0,0 +1,57 @@
+#include <stdio.h>                /* fprintf */
+#include <errno.h>                /* errno */
+#include <string.h>                /* strerror */
+#include <unistd.h>                /* read,write,close */
+#include <stdlib.h>                /* getenv,strtol */
+#include <sys/select.h>            /* select */
+#include <sys/socket.h>            /* send, recv */
+#include <sys/un.h>                /* struct sockaddr_un */
+#define BUFSIZE (2<<16)
+#undef IOSLAVE_DEBUG
+char *scratch;
+
+int send_fd(int sock_fd, int send_fd) {
+    int retval;
+    struct msghdr msg;
+    struct cmsghdr *p_cmsg;
+    struct iovec vec;
+    char cmsgbuf[CMSG_SPACE(sizeof(send_fd))];
+    int *p_fds;
+    char sendchar = 0;
+    msg.msg_control = cmsgbuf;
+    msg.msg_controllen = sizeof(cmsgbuf);
+    p_cmsg = CMSG_FIRSTHDR(&msg);
+    p_cmsg->cmsg_level = SOL_SOCKET;
+    p_cmsg->cmsg_type = SCM_RIGHTS;
+    p_cmsg->cmsg_len = CMSG_LEN(sizeof(send_fd));
+    p_fds = (int *) CMSG_DATA(p_cmsg);
+    *p_fds = send_fd;
+    msg.msg_controllen = p_cmsg->cmsg_len;
+    msg.msg_name = NULL;
+    msg.msg_namelen = 0;
+    msg.msg_iov = &vec;
+    msg.msg_iovlen = 1;
+    msg.msg_flags = 0;
+    /* "To pass file descriptors or credentials you need to send/read at
+     * least one byte" (man 7 unix)
+     */
+    vec.iov_base = &sendchar;
+    vec.iov_len = sizeof(sendchar);
+    retval = sendmsg(sock_fd, &msg, 0);
+    if (retval != 1) {
+        perror("sendmsg");
+    }
+    return retval;
+}
+
+int main() {
+    char *env = getenv("_FUSE_IOSLAVE_FD");
+    int fd;
+    if (!env)
+        exit(fprintf(stderr, "fuse_ioslave: do not run me directly\n"));
+    fd = strtol(env, NULL, 0);
+    while (send_fd(fd, 0) < 0) {
+        sleep(5);
+    }
+    return 0;
+}