support/savetransfer.c

   1 /* This program can record the stream of data flowing to or from a program.
   2  * This allows it to be used to check that rsync's data that is flowing
   3  * through a remote shell is not being corrupted (for example).
   4  *
   5  * Usage: savetransfer [-i|-o] OUTPUT_FILE PROGRAM [ARGS...]
   6  * -i  Save the input going to PROGRAM to the OUTPUT_FILE
   7  * -o  Save the output coming from PROGRAM to the OUTPUT_FILE
   8  *
   9  * If you want to capture the flow of data for an rsync command, use one of
  10  * the following commands (the resulting files should be identical):
  11  *
  12  * rsync -av --rsh="savetransfer -i /tmp/to.server ssh"
  13  *   --rsync-path="savetransfer -i /tmp/from.client rsync" SOURCE DEST
  14  *
  15  * rsync -av --rsh="savetransfer -o /tmp/from.server ssh"
  16  *   --rsync-path="savetransfer -o /tmp/to.client rsync" SOURCE DEST
  17  *
  18  * Note that this program aborts after 30 seconds of inactivity, so you'll need
  19  * to change it if that is not enough dead time for your transfer.  Also, some
  20  * of the above commands will not notice that the transfer is done (if we're
  21  * saving the input to a PROGRAM and the PROGRAM goes away:  we won't notice
  22  * that it's gone unless more data comes in) -- when this happens it will delay
  23  * at the end of the transfer until the timeout period expires.
  24  */
  25
  26 #include "../rsync.h"
  27
  28 #define TIMEOUT_SECONDS 30
  29
  30 #ifdef HAVE_SIGACTION
  31 static struct sigaction sigact;
  32 #endif
  33
  34 void run_program(char **command);
  35
  36 char buf[4096];
  37 int save_data_from_program = 0;
  38
  39 int
  40 main(int argc, char *argv[])
  41 {
  42     int fd_file, len;
  43     struct timeval tv;
  44     fd_set fds;
  45
  46     argv++;
  47     if (--argc && argv[0][0] == '-') {
  48         if (argv[0][1] == 'o')
  49             save_data_from_program = 1;
  50         else if (argv[0][1] == 'i')
  51             save_data_from_program = 0;
  52         else {
  53             fprintf(stderr, "Unknown option: %s\n", argv[0]);
  54             exit(1);
  55         }
  56         argv++;
  57         argc--;
  58     }
  59     if (argc < 2) {
  60         fprintf(stderr, "Usage: savetransfer [-i|-o] OUTPUT_FILE PROGRAM [ARGS...]\n");
  61         fprintf(stderr, "-i  Save the input going to PROGRAM to the OUTPUT_FILE\n");
  62         fprintf(stderr, "-o  Save the output coming from PROGRAM to the OUTPUT_FILE\n");
  63         exit(1);
  64     }
  65     if ((fd_file = open(*argv, O_WRONLY|O_TRUNC|O_CREAT|O_BINARY, 0644)) < 0) {
  66         fprintf(stderr, "Unable to write to `%s': %s\n", *argv, strerror(errno));
  67         exit(1);
  68     }
  69     set_blocking(fd_file);
  70
  71     SIGACTION(SIGPIPE, SIG_IGN);
  72
  73     run_program(argv + 1);
  74
  75 #if defined HAVE_SETMODE && O_BINARY
  76     setmode(STDIN_FILENO, O_BINARY);
  77     setmode(STDOUT_FILENO, O_BINARY);
  78 #endif
  79     set_nonblocking(STDIN_FILENO);
  80     set_blocking(STDOUT_FILENO);
  81
  82     while (1) {
  83         FD_ZERO(&fds);
  84         FD_SET(STDIN_FILENO, &fds);
  85         tv.tv_sec = TIMEOUT_SECONDS;
  86         tv.tv_usec = 0;
  87         if (!select(STDIN_FILENO+1, &fds, NULL, NULL, &tv))
  88             break;
  89         if (!FD_ISSET(STDIN_FILENO, &fds))
  90             break;
  91         if ((len = read(STDIN_FILENO, buf, sizeof buf)) <= 0)
  92             break;
  93         if (write(STDOUT_FILENO, buf, len) != len) {
  94             fprintf(stderr, "Failed to write data to stdout: %s\n", strerror(errno));
  95             exit(1);
  96         }
  97         if (write(fd_file, buf, len) != len) {
  98             fprintf(stderr, "Failed to write data to fd_file: %s\n", strerror(errno));
  99             exit(1);
 100         }
 101     }
 102     return 0;
 103 }
 104
 105 void
 106 run_program(char **command)
 107 {
 108     int pipe_fds[2], ret;
 109     pid_t pid;
 110
 111     if (pipe(pipe_fds) < 0) {
 112         fprintf(stderr, "pipe failed: %s\n", strerror(errno));
 113         exit(1);
 114     }
 115
 116     if ((pid = fork()) < 0) {
 117         fprintf(stderr, "fork failed: %s\n", strerror(errno));
 118         exit(1);
 119     }
 120
 121     if (pid == 0) {
 122         if (save_data_from_program)
 123             ret = dup2(pipe_fds[1], STDOUT_FILENO);
 124         else
 125             ret = dup2(pipe_fds[0], STDIN_FILENO);
 126         if (ret < 0) {
 127             fprintf(stderr, "Failed to dup (in child): %s\n", strerror(errno));
 128             exit(1);
 129         }
 130         close(pipe_fds[0]);
 131         close(pipe_fds[1]);
 132         set_blocking(STDIN_FILENO);
 133         set_blocking(STDOUT_FILENO);
 134         execvp(command[0], command);
 135         fprintf(stderr, "Failed to exec %s: %s\n", command[0], strerror(errno));
 136         exit(1);
 137     }
 138
 139     if (save_data_from_program)
 140         ret = dup2(pipe_fds[0], STDIN_FILENO);
 141     else
 142         ret = dup2(pipe_fds[1], STDOUT_FILENO);
 143     if (ret < 0) {
 144         fprintf(stderr, "Failed to dup (in parent): %s\n", strerror(errno));
 145         exit(1);
 146     }
 147     close(pipe_fds[0]);
 148     close(pipe_fds[1]);
 149 }
 150
 151 void
 152 set_nonblocking(int fd)
 153 {
 154     int val;
 155
 156     if ((val = fcntl(fd, F_GETFL, 0)) == -1)
 157         return;
 158     if (!(val & NONBLOCK_FLAG)) {
 159         val |= NONBLOCK_FLAG;
 160         fcntl(fd, F_SETFL, val);
 161     }
 162 }
 163
 164 void
 165 set_blocking(int fd)
 166 {
 167     int val;
 168
 169     if ((val = fcntl(fd, F_GETFL, 0)) < 0)
 170         return;
 171     if (val & NONBLOCK_FLAG) {
 172         val &= ~NONBLOCK_FLAG;
 173         fcntl(fd, F_SETFL, val);
 174     }
 175 }