tests/qemu-iotests/socket_scm_helper.c

   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  */
  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. */
  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  */
  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 }