sideband.c

   1 #include "pkt-line.h"
   2 #include "sideband.h"
   3
   4 /*
   5  * Receive multiplexed output stream over git native protocol.
   6  * in_stream is the input stream from the remote, which carries data
   7  * in pkt_line format with band designator.  Demultiplex it into out
   8  * and err and return error appropriately.  Band #1 carries the
   9  * primary payload.  Things coming over band #2 is not necessarily
  10  * error; they are usually informative message on the standard error
  11  * stream, aka "verbose").  A message over band #3 is a signal that
  12  * the remote died unexpectedly.  A flush() concludes the stream.
  13  */
  14 int recv_sideband(const char *me, int in_stream, int out, int err)
  15 {
  16         char buf[7 + LARGE_PACKET_MAX + 1];
  17         strcpy(buf, "remote:");
  18         while (1) {
  19                 int band, len;
  20                 len = packet_read_line(in_stream, buf+7, LARGE_PACKET_MAX);
  21                 if (len == 0)
  22                         break;
  23                 if (len < 1) {
  24                         len = sprintf(buf, "%s: protocol error: no band designator\n", me);
  25                         safe_write(err, buf, len);
  26                         return SIDEBAND_PROTOCOL_ERROR;
  27                 }
  28                 band = buf[7] & 0xff;
  29                 len--;
  30                 switch (band) {
  31                 case 3:
  32                         buf[7] = ' ';
  33                         buf[8+len] = '\n';
  34                         safe_write(err, buf, 8+len+1);
  35                         return SIDEBAND_REMOTE_ERROR;
  36                 case 2:
  37                         buf[7] = ' ';
  38                         len += 8;
  39                         while (1) {
  40                                 int brk = 8;
  41                                 while (brk < len) {
  42                                         brk++;
  43                                         if (buf[brk-1] == '\n' ||
  44                                             buf[brk-1] == '\r')
  45                                                 break;
  46                                 }
  47                                 safe_write(err, buf, brk);
  48                                 if (brk < len) {
  49                                         memmove(buf + 8, buf + brk, len - brk);
  50                                         len = len - brk + 8;
  51                                 } else
  52                                         break;
  53                         }
  54                         continue;
  55                 case 1:
  56                         safe_write(out, buf+8, len);
  57                         continue;
  58                 default:
  59                         len = sprintf(buf,
  60                                       "%s: protocol error: bad band #%d\n",
  61                                       me, band);
  62                         safe_write(err, buf, len);
  63                         return SIDEBAND_PROTOCOL_ERROR;
  64                 }
  65         }
  66         return 0;
  67 }
  68
  69 /*
  70  * fd is connected to the remote side; send the sideband data
  71  * over multiplexed packet stream.
  72  */
  73 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
  74 {
  75         ssize_t ssz = sz;
  76         const char *p = data;
  77
  78         while (sz) {
  79                 unsigned n;
  80                 char hdr[5];
  81
  82                 n = sz;
  83                 if (packet_max - 5 < n)
  84                         n = packet_max - 5;
  85                 sprintf(hdr, "%04x", n + 5);
  86                 hdr[4] = band;
  87                 safe_write(fd, hdr, 5);
  88                 safe_write(fd, p, n);
  89                 p += n;
  90                 sz -= n;
  91         }
  92         return ssz;
  93 }