sideband.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "sideband.h"
   4
   5 /*
   6  * Receive multiplexed output stream over git native protocol.
   7  * in_stream is the input stream from the remote, which carries data
   8  * in pkt_line format with band designator.  Demultiplex it into out
   9  * and err and return error appropriately.  Band #1 carries the
  10  * primary payload.  Things coming over band #2 is not necessarily
  11  * error; they are usually informative message on the standard error
  12  * stream, aka "verbose").  A message over band #3 is a signal that
  13  * the remote died unexpectedly.  A flush() concludes the stream.
  14  */
  15
  16 #define PREFIX "remote: "
  17
  18 #define ANSI_SUFFIX "\033[K"
  19 #define DUMB_SUFFIX "        "
  20
  21 int recv_sideband(const char *me, int in_stream, int out)
  22 {
  23         const char *term, *suffix;
  24         char buf[LARGE_PACKET_MAX + 1];
  25         struct strbuf outbuf = STRBUF_INIT;
  26         int retval = 0;
  27
  28         term = getenv("TERM");
  29         if (isatty(2) && term && strcmp(term, "dumb"))
  30                 suffix = ANSI_SUFFIX;
  31         else
  32                 suffix = DUMB_SUFFIX;
  33
  34         while (!retval) {
  35                 const char *b, *brk;
  36                 int band, len;
  37                 len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
  38                 if (len == 0)
  39                         break;
  40                 if (len < 1) {
  41                         strbuf_addf(&outbuf,
  42                                     "%s%s: protocol error: no band designator",
  43                                     outbuf.len ? "\n" : "", me);
  44                         retval = SIDEBAND_PROTOCOL_ERROR;
  45                         break;
  46                 }
  47                 band = buf[0] & 0xff;
  48                 buf[len] = '\0';
  49                 len--;
  50                 switch (band) {
  51                 case 3:
  52                         strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
  53                                     PREFIX, buf + 1);
  54                         retval = SIDEBAND_REMOTE_ERROR;
  55                         break;
  56                 case 2:
  57                         b = buf + 1;
  58
  59                         /*
  60                          * Append a suffix to each nonempty line to clear the
  61                          * end of the screen line.
  62                          *
  63                          * The output is accumulated in a buffer and
  64                          * each line is printed to stderr using
  65                          * write(2) to ensure inter-process atomicity.
  66                          */
  67                         while ((brk = strpbrk(b, "\n\r"))) {
  68                                 int linelen = brk - b;
  69
  70                                 if (!outbuf.len)
  71                                         strbuf_addstr(&outbuf, PREFIX);
  72                                 if (linelen > 0) {
  73                                         strbuf_addf(&outbuf, "%.*s%s%c",
  74                                                     linelen, b, suffix, *brk);
  75                                 } else {
  76                                         strbuf_addch(&outbuf, *brk);
  77                                 }
  78                                 xwrite(2, outbuf.buf, outbuf.len);
  79                                 strbuf_reset(&outbuf);
  80
  81                                 b = brk + 1;
  82                         }
  83
  84                         if (*b)
  85                                 strbuf_addf(&outbuf, "%s%s",
  86                                             outbuf.len ? "" : PREFIX, b);
  87                         break;
  88                 case 1:
  89                         write_or_die(out, buf + 1, len);
  90                         break;
  91                 default:
  92                         strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d",
  93                                     outbuf.len ? "\n" : "", me, band);
  94                         retval = SIDEBAND_PROTOCOL_ERROR;
  95                         break;
  96                 }
  97         }
  98
  99         if (outbuf.len) {
 100                 strbuf_addch(&outbuf, '\n');
 101                 xwrite(2, outbuf.buf, outbuf.len);
 102         }
 103         strbuf_release(&outbuf);
 104         return retval;
 105 }
 106
 107 /*
 108  * fd is connected to the remote side; send the sideband data
 109  * over multiplexed packet stream.
 110  */
 111 void send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
 112 {
 113         const char *p = data;
 114
 115         while (sz) {
 116                 unsigned n;
 117                 char hdr[5];
 118
 119                 n = sz;
 120                 if (packet_max - 5 < n)
 121                         n = packet_max - 5;
 122                 if (0 <= band) {
 123                         xsnprintf(hdr, sizeof(hdr), "%04x", n + 5);
 124                         hdr[4] = band;
 125                         write_or_die(fd, hdr, 5);
 126                 } else {
 127                         xsnprintf(hdr, sizeof(hdr), "%04x", n + 4);
 128                         write_or_die(fd, hdr, 4);
 129                 }
 130                 write_or_die(fd, p, n);
 131                 p += n;
 132                 sz -= n;
 133         }
 134 }