sideband.c
#include "cache.h"
#include "pkt-line.h"
#include "sideband.h"
/*
* Receive multiplexed output stream over git native protocol.
* in_stream is the input stream from the remote, which carries data
* in pkt_line format with band designator. Demultiplex it into out
* and err and return error appropriately. Band #1 carries the
* primary payload. Things coming over band #2 is not necessarily
* error; they are usually informative message on the standard error
* stream, aka "verbose"). A message over band #3 is a signal that
* the remote died unexpectedly. A flush() concludes the stream.
*/
#define PREFIX "remote: "
#define ANSI_SUFFIX "\033[K"
#define DUMB_SUFFIX " "
int recv_sideband(const char *me, int in_stream, int out)
{
const char *term, *suffix;
char buf[LARGE_PACKET_MAX + 1];
struct strbuf outbuf = STRBUF_INIT;
int retval = 0;
term = getenv("TERM");
if (isatty(2) && term && strcmp(term, "dumb"))
suffix = ANSI_SUFFIX;
else
suffix = DUMB_SUFFIX;
while (!retval) {
const char *b, *brk;
int band, len;
len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
if (len == 0)
break;
if (len < 1) {
strbuf_addf(&outbuf,
"%s%s: protocol error: no band designator",
outbuf.len ? "\n" : "", me);
retval = SIDEBAND_PROTOCOL_ERROR;
break;
}
band = buf[0] & 0xff;
buf[len] = '\0';
len--;
switch (band) {
case 3:
strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
PREFIX, buf + 1);
retval = SIDEBAND_REMOTE_ERROR;
break;
case 2:
b = buf + 1;
/*
* Append a suffix to each nonempty line to clear the
* end of the screen line.
*
* The output is accumulated in a buffer and
* each line is printed to stderr using
* write(2) to ensure inter-process atomicity.
*/
while ((brk = strpbrk(b, "\n\r"))) {
int linelen = brk - b;
if (!outbuf.len)
strbuf_addstr(&outbuf, PREFIX);
if (linelen > 0) {
strbuf_addf(&outbuf, "%.*s%s%c",
linelen, b, suffix, *brk);
} else {
strbuf_addch(&outbuf, *brk);
}
xwrite(2, outbuf.buf, outbuf.len);
strbuf_reset(&outbuf);
b = brk + 1;
}
if (*b)
strbuf_addf(&outbuf, "%s%s",
outbuf.len ? "" : PREFIX, b);
break;
case 1:
write_or_die(out, buf + 1, len);
break;
default:
strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d",
outbuf.len ? "\n" : "", me, band);
retval = SIDEBAND_PROTOCOL_ERROR;
break;
}
}
if (outbuf.len) {
strbuf_addch(&outbuf, '\n');
xwrite(2, outbuf.buf, outbuf.len);
}
strbuf_release(&outbuf);
return retval;
}
/*
* fd is connected to the remote side; send the sideband data
* over multiplexed packet stream.
*/
void send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
{
const char *p = data;
while (sz) {
unsigned n;
char hdr[5];
n = sz;
if (packet_max - 5 < n)
n = packet_max - 5;
if (0 <= band) {
xsnprintf(hdr, sizeof(hdr), "%04x", n + 5);
hdr[4] = band;
write_or_die(fd, hdr, 5);
} else {
xsnprintf(hdr, sizeof(hdr), "%04x", n + 4);
write_or_die(fd, hdr, 4);
}
write_or_die(fd, p, n);
p += n;
sz -= n;
}
}