git/pkt-line.c
Nicolas Pitre b3d9899324 make git a bit less cryptic on fetch errors
The remote server might not want to tell why it doesn't like us for
security reasons, but let's make the client report such error in a bit
less confusing way.  The remote failure remains a mystery, but the local
message might be a bit less so.

[jc: with a gentle wording updates from Andy Parkins]

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-18 15:31:28 -08:00

115 lines
2.5 KiB
C

#include "cache.h"
#include "pkt-line.h"
/*
* Write a packetized stream, where each line is preceded by
* its length (including the header) as a 4-byte hex number.
* A length of 'zero' means end of stream (and a length of 1-3
* would be an error).
*
* This is all pretty stupid, but we use this packetized line
* format to make a streaming format possible without ever
* over-running the read buffers. That way we'll never read
* into what might be the pack data (which should go to another
* process entirely).
*
* The writing side could use stdio, but since the reading
* side can't, we stay with pure read/write interfaces.
*/
ssize_t safe_write(int fd, const void *buf, ssize_t n)
{
ssize_t nn = n;
while (n) {
int ret = xwrite(fd, buf, n);
if (ret > 0) {
buf = (char *) buf + ret;
n -= ret;
continue;
}
if (!ret)
die("write error (disk full?)");
die("write error (%s)", strerror(errno));
}
return nn;
}
/*
* If we buffered things up above (we don't, but we should),
* we'd flush it here
*/
void packet_flush(int fd)
{
safe_write(fd, "0000", 4);
}
#define hex(a) (hexchar[(a) & 15])
void packet_write(int fd, const char *fmt, ...)
{
static char buffer[1000];
static char hexchar[] = "0123456789abcdef";
va_list args;
unsigned n;
va_start(args, fmt);
n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
va_end(args);
if (n >= sizeof(buffer)-4)
die("protocol error: impossibly long line");
n += 4;
buffer[0] = hex(n >> 12);
buffer[1] = hex(n >> 8);
buffer[2] = hex(n >> 4);
buffer[3] = hex(n);
safe_write(fd, buffer, n);
}
static void safe_read(int fd, void *buffer, unsigned size)
{
int n = 0;
while (n < size) {
int ret = xread(fd, (char *) buffer + n, size - n);
if (ret < 0)
die("read error (%s)", strerror(errno));
if (!ret)
die("The remote end hung up unexpectedly");
n += ret;
}
}
int packet_read_line(int fd, char *buffer, unsigned size)
{
int n;
unsigned len;
char linelen[4];
safe_read(fd, linelen, 4);
len = 0;
for (n = 0; n < 4; n++) {
unsigned char c = linelen[n];
len <<= 4;
if (c >= '0' && c <= '9') {
len += c - '0';
continue;
}
if (c >= 'a' && c <= 'f') {
len += c - 'a' + 10;
continue;
}
if (c >= 'A' && c <= 'F') {
len += c - 'A' + 10;
continue;
}
die("protocol error: bad line length character");
}
if (!len)
return 0;
len -= 4;
if (len >= size)
die("protocol error: bad line length %d", len);
safe_read(fd, buffer, len);
buffer[len] = 0;
return len;
}