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, char *buf, int bufsz)
  15 {
  16         while (1) {
  17                 int len = packet_read_line(in_stream, buf, bufsz);
  18                 if (len == 0)
  19                         break;
  20                 if (len < 1) {
  21                         len = sprintf(buf, "%s: protocol error: no band designator\n", me);
  22                         safe_write(err, buf, len);
  23                         return SIDEBAND_PROTOCOL_ERROR;
  24                 }
  25                 len--;
  26                 switch (buf[0] & 0xFF) {
  27                 case 3:
  28                         safe_write(err, "remote: ", 8);
  29                         safe_write(err, buf+1, len);
  30                         safe_write(err, "\n", 1);
  31                         return SIDEBAND_REMOTE_ERROR;
  32                 case 2:
  33                         safe_write(err, "remote: ", 8);
  34                         safe_write(err, buf+1, len);
  35                         continue;
  36                 case 1:
  37                         safe_write(out, buf+1, len);
  38                         continue;
  39                 default:
  40                         len = sprintf(buf + 1,
  41                                       "%s: protocol error: bad band #%d\n",
  42                                       me, buf[0] & 0xFF);
  43                         safe_write(err, buf+1, len);
  44                         return SIDEBAND_PROTOCOL_ERROR;
  45                 }
  46         }
  47         return 0;
  48 }
  49
  50 /*
  51  * fd is connected to the remote side; send the sideband data
  52  * over multiplexed packet stream.
  53  */
  54 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
  55 {
  56         ssize_t ssz = sz;
  57         const char *p = data;
  58
  59         while (sz) {
  60                 unsigned n;
  61                 char hdr[5];
  62
  63                 n = sz;
  64                 if (packet_max - 5 < n)
  65                         n = packet_max - 5;
  66                 sprintf(hdr, "%04x", n + 5);
  67                 hdr[4] = band;
  68                 safe_write(fd, hdr, 5);
  69                 safe_write(fd, p, n);
  70                 p += n;
  71                 sz -= n;
  72         }
  73         return ssz;
  74 }