git/pkt-line.c
René Scharfe d23309733a introduce hex2chr() for converting two hexadecimal digits to a character
Add and use a helper function that decodes the char value of two
hexadecimal digits.  It returns a negative number on error, avoids
running over the end of the given string and doesn't shift negative
values.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-07 10:42:46 -07:00

232 lines
5.2 KiB
C

#include "cache.h"
#include "pkt-line.h"
#include "run-command.h"
char packet_buffer[LARGE_PACKET_MAX];
static const char *packet_trace_prefix = "git";
static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
void packet_trace_identity(const char *prog)
{
packet_trace_prefix = xstrdup(prog);
}
static const char *get_trace_prefix(void)
{
return in_async() ? "sideband" : packet_trace_prefix;
}
static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
{
if (!sideband) {
trace_verbatim(&trace_pack, buf, len);
return 1;
} else if (len && *buf == '\1') {
trace_verbatim(&trace_pack, buf + 1, len - 1);
return 1;
} else {
/* it's another non-pack sideband */
return 0;
}
}
static void packet_trace(const char *buf, unsigned int len, int write)
{
int i;
struct strbuf out;
static int in_pack, sideband;
if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
return;
if (in_pack) {
if (packet_trace_pack(buf, len, sideband))
return;
} else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
in_pack = 1;
sideband = *buf == '\1';
packet_trace_pack(buf, len, sideband);
/*
* Make a note in the human-readable trace that the pack data
* started.
*/
buf = "PACK ...";
len = strlen(buf);
}
if (!trace_want(&trace_packet))
return;
/* +32 is just a guess for header + quoting */
strbuf_init(&out, len+32);
strbuf_addf(&out, "packet: %12s%c ",
get_trace_prefix(), write ? '>' : '<');
/* XXX we should really handle printable utf8 */
for (i = 0; i < len; i++) {
/* suppress newlines */
if (buf[i] == '\n')
continue;
if (buf[i] >= 0x20 && buf[i] <= 0x7e)
strbuf_addch(&out, buf[i]);
else
strbuf_addf(&out, "\\%o", buf[i]);
}
strbuf_addch(&out, '\n');
trace_strbuf(&trace_packet, &out);
strbuf_release(&out);
}
/*
* If we buffered things up above (we don't, but we should),
* we'd flush it here
*/
void packet_flush(int fd)
{
packet_trace("0000", 4, 1);
write_or_die(fd, "0000", 4);
}
void packet_buf_flush(struct strbuf *buf)
{
packet_trace("0000", 4, 1);
strbuf_add(buf, "0000", 4);
}
#define hex(a) (hexchar[(a) & 15])
static void format_packet(struct strbuf *out, const char *fmt, va_list args)
{
static char hexchar[] = "0123456789abcdef";
size_t orig_len, n;
orig_len = out->len;
strbuf_addstr(out, "0000");
strbuf_vaddf(out, fmt, args);
n = out->len - orig_len;
if (n > LARGE_PACKET_MAX)
die("protocol error: impossibly long line");
out->buf[orig_len + 0] = hex(n >> 12);
out->buf[orig_len + 1] = hex(n >> 8);
out->buf[orig_len + 2] = hex(n >> 4);
out->buf[orig_len + 3] = hex(n);
packet_trace(out->buf + orig_len + 4, n - 4, 1);
}
void packet_write(int fd, const char *fmt, ...)
{
static struct strbuf buf = STRBUF_INIT;
va_list args;
strbuf_reset(&buf);
va_start(args, fmt);
format_packet(&buf, fmt, args);
va_end(args);
write_or_die(fd, buf.buf, buf.len);
}
void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
format_packet(buf, fmt, args);
va_end(args);
}
static int get_packet_data(int fd, char **src_buf, size_t *src_size,
void *dst, unsigned size, int options)
{
ssize_t ret;
if (fd >= 0 && src_buf && *src_buf)
die("BUG: multiple sources given to packet_read");
/* Read up to "size" bytes from our source, whatever it is. */
if (src_buf && *src_buf) {
ret = size < *src_size ? size : *src_size;
memcpy(dst, *src_buf, ret);
*src_buf += ret;
*src_size -= ret;
} else {
ret = read_in_full(fd, dst, size);
if (ret < 0)
die_errno("read error");
}
/* And complain if we didn't get enough bytes to satisfy the read. */
if (ret < size) {
if (options & PACKET_READ_GENTLE_ON_EOF)
return -1;
die("The remote end hung up unexpectedly");
}
return ret;
}
static int packet_length(const char *linelen)
{
int val = hex2chr(linelen);
return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
}
int packet_read(int fd, char **src_buf, size_t *src_len,
char *buffer, unsigned size, int options)
{
int len, ret;
char linelen[4];
ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
if (ret < 0)
return ret;
len = packet_length(linelen);
if (len < 0)
die("protocol error: bad line length character: %.4s", linelen);
if (!len) {
packet_trace("0000", 4, 0);
return 0;
}
len -= 4;
if (len >= size)
die("protocol error: bad line length %d", len);
ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
if (ret < 0)
return ret;
if ((options & PACKET_READ_CHOMP_NEWLINE) &&
len && buffer[len-1] == '\n')
len--;
buffer[len] = 0;
packet_trace(buffer, len, 0);
return len;
}
static char *packet_read_line_generic(int fd,
char **src, size_t *src_len,
int *dst_len)
{
int len = packet_read(fd, src, src_len,
packet_buffer, sizeof(packet_buffer),
PACKET_READ_CHOMP_NEWLINE);
if (dst_len)
*dst_len = len;
return len ? packet_buffer : NULL;
}
char *packet_read_line(int fd, int *len_p)
{
return packet_read_line_generic(fd, NULL, NULL, len_p);
}
char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
{
return packet_read_line_generic(-1, src, src_len, dst_len);
}