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f93296ea WX |
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 <stdio.h> | |
14 | #include <errno.h> | |
15 | #include <sys/socket.h> | |
16 | #include <sys/un.h> | |
17 | #include <stdlib.h> | |
18 | #include <sys/types.h> | |
19 | #include <sys/stat.h> | |
20 | #include <fcntl.h> | |
21 | #include <unistd.h> | |
22 | ||
23 | /* #define SOCKET_SCM_DEBUG */ | |
24 | ||
25 | /* | |
26 | * @fd and @fd_to_send will not be checked for validation in this function, | |
27 | * a blank will be sent as iov data to notify qemu. | |
28 | */ | |
29 | static int send_fd(int fd, int fd_to_send) | |
30 | { | |
31 | struct msghdr msg; | |
32 | struct iovec iov[1]; | |
33 | int ret; | |
34 | char control[CMSG_SPACE(sizeof(int))]; | |
35 | struct cmsghdr *cmsg; | |
36 | ||
37 | memset(&msg, 0, sizeof(msg)); | |
38 | memset(control, 0, sizeof(control)); | |
39 | ||
40 | /* Send a blank to notify qemu */ | |
41 | iov[0].iov_base = (void *)" "; | |
42 | iov[0].iov_len = 1; | |
43 | ||
44 | msg.msg_iov = iov; | |
45 | msg.msg_iovlen = 1; | |
46 | ||
47 | msg.msg_control = control; | |
48 | msg.msg_controllen = sizeof(control); | |
49 | ||
50 | cmsg = CMSG_FIRSTHDR(&msg); | |
51 | ||
52 | cmsg->cmsg_len = CMSG_LEN(sizeof(int)); | |
53 | cmsg->cmsg_level = SOL_SOCKET; | |
54 | cmsg->cmsg_type = SCM_RIGHTS; | |
55 | memcpy(CMSG_DATA(cmsg), &fd, sizeof(int)); | |
56 | ||
57 | do { | |
58 | ret = sendmsg(fd, &msg, 0); | |
59 | } while (ret < 0 && errno == EINTR); | |
60 | ||
61 | if (ret < 0) { | |
62 | fprintf(stderr, "Failed to send msg, reason: %s\n", strerror(errno)); | |
63 | } | |
64 | ||
65 | return ret; | |
66 | } | |
67 | ||
68 | /* Convert string to fd number. */ | |
69 | static int get_fd_num(const char *fd_str) | |
70 | { | |
71 | int sock; | |
72 | char *err; | |
73 | ||
74 | errno = 0; | |
75 | sock = strtol(fd_str, &err, 10); | |
76 | if (errno) { | |
77 | fprintf(stderr, "Failed in strtol for socket fd, reason: %s\n", | |
78 | strerror(errno)); | |
79 | return -1; | |
80 | } | |
81 | if (!*fd_str || *err || sock < 0) { | |
82 | fprintf(stderr, "bad numerical value for socket fd '%s'\n", fd_str); | |
83 | return -1; | |
84 | } | |
85 | ||
86 | return sock; | |
87 | } | |
88 | ||
89 | /* | |
90 | * To make things simple, the caller needs to specify: | |
91 | * 1. socket fd. | |
92 | * 2. path of the file to be sent. | |
93 | */ | |
94 | int main(int argc, char **argv, char **envp) | |
95 | { | |
96 | int sock, fd, ret; | |
97 | ||
98 | #ifdef SOCKET_SCM_DEBUG | |
99 | int i; | |
100 | for (i = 0; i < argc; i++) { | |
101 | fprintf(stderr, "Parameter %d: %s\n", i, argv[i]); | |
102 | } | |
103 | #endif | |
104 | ||
105 | if (argc != 3) { | |
106 | fprintf(stderr, | |
107 | "Usage: %s < socket-fd > < file-path >\n", | |
108 | argv[0]); | |
109 | return EXIT_FAILURE; | |
110 | } | |
111 | ||
112 | ||
113 | sock = get_fd_num(argv[1]); | |
114 | if (sock < 0) { | |
115 | return EXIT_FAILURE; | |
116 | } | |
117 | ||
118 | /* Now only open a file in readonly mode for test purpose. If more precise | |
119 | control is needed, use python script in file operation, which is | |
120 | 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 | ret = send_fd(sock, fd); | |
128 | if (ret < 0) { | |
129 | close(fd); | |
130 | return EXIT_FAILURE; | |
131 | } | |
132 | ||
133 | close(fd); | |
134 | return EXIT_SUCCESS; | |
135 | } |