1 /*
2 * SCM_RIGHTS with unix socket help program for test
3 *
4 * Copyright IBM, Inc. 2013
5 *
6 * Authors:
7 * Wenchao Xia <xiawenc@linux.vnet.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 */
12
13 #include "qemu/osdep.h"
14 #include <sys/socket.h>
15 #include <sys/un.h>
16
17 /* #define SOCKET_SCM_DEBUG */
18
19 /*
20 * @fd and @fd_to_send will not be checked for validation in this function,
21 * a blank will be sent as iov data to notify qemu.
22 */
send_fd(int fd,int fd_to_send)23 static int send_fd(int fd, int fd_to_send)
24 {
25 struct msghdr msg;
26 struct iovec iov[1];
27 int ret;
28 char control[CMSG_SPACE(sizeof(int))];
29 struct cmsghdr *cmsg;
30
31 memset(&msg, 0, sizeof(msg));
32 memset(control, 0, sizeof(control));
33
34 /* Send a blank to notify qemu */
35 iov[0].iov_base = (void *)" ";
36 iov[0].iov_len = 1;
37
38 msg.msg_iov = iov;
39 msg.msg_iovlen = 1;
40
41 msg.msg_control = control;
42 msg.msg_controllen = sizeof(control);
43
44 cmsg = CMSG_FIRSTHDR(&msg);
45
46 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
47 cmsg->cmsg_level = SOL_SOCKET;
48 cmsg->cmsg_type = SCM_RIGHTS;
49 memcpy(CMSG_DATA(cmsg), &fd_to_send, sizeof(int));
50
51 do {
52 ret = sendmsg(fd, &msg, 0);
53 } while (ret < 0 && errno == EINTR);
54
55 if (ret < 0) {
56 fprintf(stderr, "Failed to send msg, reason: %s\n", strerror(errno));
57 }
58
59 return ret;
60 }
61
62 /* Convert string to fd number. */
get_fd_num(const char * fd_str,bool silent)63 static int get_fd_num(const char *fd_str, bool silent)
64 {
65 int sock;
66 char *err;
67
68 errno = 0;
69 sock = strtol(fd_str, &err, 10);
70 if (errno) {
71 if (!silent) {
72 fprintf(stderr, "Failed in strtol for socket fd, reason: %s\n",
73 strerror(errno));
74 }
75 return -1;
76 }
77 if (!*fd_str || *err || sock < 0) {
78 if (!silent) {
79 fprintf(stderr, "bad numerical value for socket fd '%s'\n", fd_str);
80 }
81 return -1;
82 }
83
84 return sock;
85 }
86
87 /*
88 * To make things simple, the caller needs to specify:
89 * 1. socket fd.
90 * 2. path of the file to be sent.
91 */
main(int argc,char ** argv,char ** envp)92 int main(int argc, char **argv, char **envp)
93 {
94 int sock, fd, ret;
95
96 #ifdef SOCKET_SCM_DEBUG
97 int i;
98 for (i = 0; i < argc; i++) {
99 fprintf(stderr, "Parameter %d: %s\n", i, argv[i]);
100 }
101 #endif
102
103 if (argc != 3) {
104 fprintf(stderr,
105 "Usage: %s < socket-fd > < file-path >\n",
106 argv[0]);
107 return EXIT_FAILURE;
108 }
109
110
111 sock = get_fd_num(argv[1], false);
112 if (sock < 0) {
113 return EXIT_FAILURE;
114 }
115
116 fd = get_fd_num(argv[2], true);
117 if (fd < 0) {
118 /* Now only open a file in readonly mode for test purpose. If more
119 precise control is needed, use python script in file operation, which
120 is supposed to fork and exec this program. */
121 fd = open(argv[2], O_RDONLY);
122 if (fd < 0) {
123 fprintf(stderr, "Failed to open file '%s'\n", argv[2]);
124 return EXIT_FAILURE;
125 }
126 }
127
128 ret = send_fd(sock, fd);
129 if (ret < 0) {
130 close(fd);
131 return EXIT_FAILURE;
132 }
133
134 close(fd);
135 return EXIT_SUCCESS;
136 }
137