packv4: nth_packed_object_sha1() packv4 support
[git/packv4.git] / sideband.c
blob277fa3c10d19ee7997ee5b38c5f77a6cd04576f1
1 #include "pkt-line.h"
2 #include "sideband.h"
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.
14 int recv_sideband(const char *me, int in_stream, int out, int err)
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;
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 safe_write(err, buf, 8+len);
39 continue;
40 case 1:
41 safe_write(out, buf+8, len);
42 continue;
43 default:
44 len = sprintf(buf,
45 "%s: protocol error: bad band #%d\n",
46 me, band);
47 safe_write(err, buf, len);
48 return SIDEBAND_PROTOCOL_ERROR;
51 return 0;
55 * fd is connected to the remote side; send the sideband data
56 * over multiplexed packet stream.
58 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
60 ssize_t ssz = sz;
61 const char *p = data;
63 while (sz) {
64 unsigned n;
65 char hdr[5];
67 n = sz;
68 if (packet_max - 5 < n)
69 n = packet_max - 5;
70 sprintf(hdr, "%04x", n + 5);
71 hdr[4] = band;
72 safe_write(fd, hdr, 5);
73 safe_write(fd, p, n);
74 p += n;
75 sz -= n;
77 return ssz;