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 #define FIX_SIZE 10  /* large enough for any of the above */
  22
  23 int recv_sideband(const char *me, int in_stream, int out)
  24 {
  25         unsigned pf = strlen(PREFIX);
  26         unsigned sf;
  27         char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
  28         char *suffix, *term;
  29         int skip_pf = 0;
  30
  31         memcpy(buf, PREFIX, pf);
  32         term = getenv("TERM");
  33         if (isatty(2) && term && strcmp(term, "dumb"))
  34                 suffix = ANSI_SUFFIX;
  35         else
  36                 suffix = DUMB_SUFFIX;
  37         sf = strlen(suffix);
  38
  39         while (1) {
  40                 int band, len;
  41                 len = packet_read(in_stream, NULL, NULL, buf + pf, LARGE_PACKET_MAX, 0);
  42                 if (len == 0)
  43                         break;
  44                 if (len < 1) {
  45                         fprintf(stderr, "%s: protocol error: no band designator\n", me);
  46                         return SIDEBAND_PROTOCOL_ERROR;
  47                 }
  48                 band = buf[pf] & 0xff;
  49                 len--;
  50                 switch (band) {
  51                 case 3:
  52                         buf[pf] = ' ';
  53                         buf[pf+1+len] = '\0';
  54                         fprintf(stderr, "%s\n", buf);
  55                         return SIDEBAND_REMOTE_ERROR;
  56                 case 2:
  57                         buf[pf] = ' ';
  58                         do {
  59                                 char *b = buf;
  60                                 int brk = 0;
  61
  62                                 /*
  63                                  * If the last buffer didn't end with a line
  64                                  * break then we should not print a prefix
  65                                  * this time around.
  66                                  */
  67                                 if (skip_pf) {
  68                                         b += pf+1;
  69                                 } else {
  70                                         len += pf+1;
  71                                         brk += pf+1;
  72                                 }
  73
  74                                 /* Look for a line break. */
  75                                 for (;;) {
  76                                         brk++;
  77                                         if (brk > len) {
  78                                                 brk = 0;
  79                                                 break;
  80                                         }
  81                                         if (b[brk-1] == '\n' ||
  82                                             b[brk-1] == '\r')
  83                                                 break;
  84                                 }
  85
  86                                 /*
  87                                  * Let's insert a suffix to clear the end
  88                                  * of the screen line if a line break was
  89                                  * found.  Also, if we don't skip the
  90                                  * prefix, then a non-empty string must be
  91                                  * present too.
  92                                  */
  93                                 if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
  94                                         char save[FIX_SIZE];
  95                                         memcpy(save, b + brk, sf);
  96                                         b[brk + sf - 1] = b[brk - 1];
  97                                         memcpy(b + brk - 1, suffix, sf);
  98                                         fprintf(stderr, "%.*s", brk + sf, b);
  99                                         memcpy(b + brk, save, sf);
 100                                         len -= brk;
 101                                 } else {
 102                                         int l = brk ? brk : len;
 103                                         fprintf(stderr, "%.*s", l, b);
 104                                         len -= l;
 105                                 }
 106
 107                                 skip_pf = !brk;
 108                                 memmove(buf + pf+1, b + brk, len);
 109                         } while (len);
 110                         continue;
 111                 case 1:
 112                         write_or_die(out, buf + pf+1, len);
 113                         continue;
 114                 default:
 115                         fprintf(stderr, "%s: protocol error: bad band #%d\n",
 116                                 me, band);
 117                         return SIDEBAND_PROTOCOL_ERROR;
 118                 }
 119         }
 120         return 0;
 121 }
 122
 123 /*
 124  * fd is connected to the remote side; send the sideband data
 125  * over multiplexed packet stream.
 126  */
 127 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
 128 {
 129         ssize_t ssz = sz;
 130         const char *p = data;
 131
 132         while (sz) {
 133                 unsigned n;
 134                 char hdr[5];
 135
 136                 n = sz;
 137                 if (packet_max - 5 < n)
 138                         n = packet_max - 5;
 139                 if (0 <= band) {
 140                         xsnprintf(hdr, sizeof(hdr), "%04x", n + 5);
 141                         hdr[4] = band;
 142                         write_or_die(fd, hdr, 5);
 143                 } else {
 144                         xsnprintf(hdr, sizeof(hdr), "%04x", n + 4);
 145                         write_or_die(fd, hdr, 4);
 146                 }
 147                 write_or_die(fd, p, n);
 148                 p += n;
 149                 sz -= n;
 150         }
 151         return ssz;
 152 }