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
  15 #define PREFIX "remote:"
  16
  17 #define ANSI_SUFFIX "\033[K"
  18 #define DUMB_SUFFIX "        "
  19
  20 #define FIX_SIZE 10  /* large enough for any of the above */
  21
  22 int recv_sideband(const char *me, int in_stream, int out)
  23 {
  24         unsigned pf = strlen(PREFIX);
  25         unsigned sf;
  26         char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
  27         char *suffix, *term;
  28         int skip_pf = 0;
  29
  30         memcpy(buf, PREFIX, pf);
  31         term = getenv("TERM");
  32         if (term && strcmp(term, "dumb"))
  33                 suffix = ANSI_SUFFIX;
  34         else
  35                 suffix = DUMB_SUFFIX;
  36         sf = strlen(suffix);
  37
  38         while (1) {
  39                 int band, len;
  40                 len = packet_read_line(in_stream, buf + pf, LARGE_PACKET_MAX);
  41                 if (len == 0)
  42                         break;
  43                 if (len < 1) {
  44                         fprintf(stderr, "%s: protocol error: no band designator\n", me);
  45                         return SIDEBAND_PROTOCOL_ERROR;
  46                 }
  47                 band = buf[pf] & 0xff;
  48                 len--;
  49                 switch (band) {
  50                 case 3:
  51                         buf[pf] = ' ';
  52                         buf[pf+1+len] = '\0';
  53                         fprintf(stderr, "%s\n", buf);
  54                         return SIDEBAND_REMOTE_ERROR;
  55                 case 2:
  56                         buf[pf] = ' ';
  57                         do {
  58                                 char *b = buf;
  59                                 int brk = 0;
  60
  61                                 /*
  62                                  * If the last buffer didn't end with a line
  63                                  * break then we should not print a prefix
  64                                  * this time around.
  65                                  */
  66                                 if (skip_pf) {
  67                                         b += pf+1;
  68                                 } else {
  69                                         len += pf+1;
  70                                         brk += pf+1;
  71                                 }
  72
  73                                 /* Look for a line break. */
  74                                 for (;;) {
  75                                         brk++;
  76                                         if (brk > len) {
  77                                                 brk = 0;
  78                                                 break;
  79                                         }
  80                                         if (b[brk-1] == '\n' ||
  81                                             b[brk-1] == '\r')
  82                                                 break;
  83                                 }
  84
  85                                 /*
  86                                  * Let's insert a suffix to clear the end
  87                                  * of the screen line if a line break was
  88                                  * found.  Also, if we don't skip the
  89                                  * prefix, then a non-empty string must be
  90                                  * present too.
  91                                  */
  92                                 if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
  93                                         char save[FIX_SIZE];
  94                                         memcpy(save, b + brk, sf);
  95                                         b[brk + sf - 1] = b[brk - 1];
  96                                         memcpy(b + brk - 1, suffix, sf);
  97                                         fprintf(stderr, "%.*s", brk + sf, b);
  98                                         memcpy(b + brk, save, sf);
  99                                         len -= brk;
 100                                 } else {
 101                                         int l = brk ? brk : len;
 102                                         fprintf(stderr, "%.*s", l, b);
 103                                         len -= l;
 104                                 }
 105
 106                                 skip_pf = !brk;
 107                                 memmove(buf + pf+1, b + brk, len);
 108                         } while (len);
 109                         continue;
 110                 case 1:
 111                         safe_write(out, buf + pf+1, len);
 112                         continue;
 113                 default:
 114                         fprintf(stderr, "%s: protocol error: bad band #%d\n",
 115                                 me, band);
 116                         return SIDEBAND_PROTOCOL_ERROR;
 117                 }
 118         }
 119         return 0;
 120 }
 121
 122 /*
 123  * fd is connected to the remote side; send the sideband data
 124  * over multiplexed packet stream.
 125  */
 126 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
 127 {
 128         ssize_t ssz = sz;
 129         const char *p = data;
 130
 131         while (sz) {
 132                 unsigned n;
 133                 char hdr[5];
 134
 135                 n = sz;
 136                 if (packet_max - 5 < n)
 137                         n = packet_max - 5;
 138                 if (0 <= band) {
 139                         sprintf(hdr, "%04x", n + 5);
 140                         hdr[4] = band;
 141                         safe_write(fd, hdr, 5);
 142                 } else {
 143                         sprintf(hdr, "%04x", n + 4);
 144                         safe_write(fd, hdr, 4);
 145                 }
 146                 safe_write(fd, p, n);
 147                 p += n;
 148                 sz -= n;
 149         }
 150         return ssz;
 151 }