git/pkt-line.c
Brandon Williams f1f4d8acf4 pkt-line: add packet_buf_write_len function
Add the 'packet_buf_write_len()' function which allows for writing an
arbitrary length buffer into a 'struct strbuf' and formatting it in
packet-line format.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-15 12:01:09 -07:00

485 lines
11 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_delim(int fd)
{
packet_trace("0001", 4, 1);
write_or_die(fd, "0001", 4);
}
int packet_flush_gently(int fd)
{
packet_trace("0000", 4, 1);
if (write_in_full(fd, "0000", 4) < 0)
return error("flush packet write failed");
return 0;
}
void packet_buf_flush(struct strbuf *buf)
{
packet_trace("0000", 4, 1);
strbuf_add(buf, "0000", 4);
}
void packet_buf_delim(struct strbuf *buf)
{
packet_trace("0001", 4, 1);
strbuf_add(buf, "0001", 4);
}
static void set_packet_header(char *buf, const int size)
{
static char hexchar[] = "0123456789abcdef";
#define hex(a) (hexchar[(a) & 15])
buf[0] = hex(size >> 12);
buf[1] = hex(size >> 8);
buf[2] = hex(size >> 4);
buf[3] = hex(size);
#undef hex
}
static void format_packet(struct strbuf *out, const char *fmt, va_list args)
{
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");
set_packet_header(&out->buf[orig_len], n);
packet_trace(out->buf + orig_len + 4, n - 4, 1);
}
static int packet_write_fmt_1(int fd, int gently,
const char *fmt, va_list args)
{
static struct strbuf buf = STRBUF_INIT;
strbuf_reset(&buf);
format_packet(&buf, fmt, args);
if (write_in_full(fd, buf.buf, buf.len) < 0) {
if (!gently) {
check_pipe(errno);
die_errno("packet write with format failed");
}
return error("packet write with format failed");
}
return 0;
}
void packet_write_fmt(int fd, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
packet_write_fmt_1(fd, 0, fmt, args);
va_end(args);
}
int packet_write_fmt_gently(int fd, const char *fmt, ...)
{
int status;
va_list args;
va_start(args, fmt);
status = packet_write_fmt_1(fd, 1, fmt, args);
va_end(args);
return status;
}
static int packet_write_gently(const int fd_out, const char *buf, size_t size)
{
static char packet_write_buffer[LARGE_PACKET_MAX];
size_t packet_size;
if (size > sizeof(packet_write_buffer) - 4)
return error("packet write failed - data exceeds max packet size");
packet_trace(buf, size, 1);
packet_size = size + 4;
set_packet_header(packet_write_buffer, packet_size);
memcpy(packet_write_buffer + 4, buf, size);
if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
return error("packet write failed");
return 0;
}
void packet_write(int fd_out, const char *buf, size_t size)
{
if (packet_write_gently(fd_out, buf, size))
die_errno("packet write failed");
}
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);
}
void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
{
size_t orig_len, n;
orig_len = buf->len;
strbuf_addstr(buf, "0000");
strbuf_add(buf, data, len);
n = buf->len - orig_len;
if (n > LARGE_PACKET_MAX)
die("protocol error: impossibly long line");
set_packet_header(&buf->buf[orig_len], n);
packet_trace(data, len, 1);
}
int write_packetized_from_fd(int fd_in, int fd_out)
{
static char buf[LARGE_PACKET_DATA_MAX];
int err = 0;
ssize_t bytes_to_write;
while (!err) {
bytes_to_write = xread(fd_in, buf, sizeof(buf));
if (bytes_to_write < 0)
return COPY_READ_ERROR;
if (bytes_to_write == 0)
break;
err = packet_write_gently(fd_out, buf, bytes_to_write);
}
if (!err)
err = packet_flush_gently(fd_out);
return err;
}
int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
{
int err = 0;
size_t bytes_written = 0;
size_t bytes_to_write;
while (!err) {
if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
bytes_to_write = LARGE_PACKET_DATA_MAX;
else
bytes_to_write = len - bytes_written;
if (bytes_to_write == 0)
break;
err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
bytes_written += bytes_to_write;
}
if (!err)
err = packet_flush_gently(fd_out);
return err;
}
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);
}
enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
size_t *src_len, char *buffer,
unsigned size, int *pktlen,
int options)
{
int len;
char linelen[4];
if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
*pktlen = -1;
return PACKET_READ_EOF;
}
len = packet_length(linelen);
if (len < 0) {
die("protocol error: bad line length character: %.4s", linelen);
} else if (!len) {
packet_trace("0000", 4, 0);
*pktlen = 0;
return PACKET_READ_FLUSH;
} else if (len == 1) {
packet_trace("0001", 4, 0);
*pktlen = 0;
return PACKET_READ_DELIM;
} else if (len < 4) {
die("protocol error: bad line length %d", len);
}
len -= 4;
if ((unsigned)len >= size)
die("protocol error: bad line length %d", len);
if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
*pktlen = -1;
return PACKET_READ_EOF;
}
if ((options & PACKET_READ_CHOMP_NEWLINE) &&
len && buffer[len-1] == '\n')
len--;
buffer[len] = 0;
packet_trace(buffer, len, 0);
*pktlen = len;
return PACKET_READ_NORMAL;
}
int packet_read(int fd, char **src_buffer, size_t *src_len,
char *buffer, unsigned size, int options)
{
int pktlen = -1;
packet_read_with_status(fd, src_buffer, src_len, buffer, size,
&pktlen, options);
return pktlen;
}
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 > 0) ? packet_buffer : NULL;
}
char *packet_read_line(int fd, int *len_p)
{
return packet_read_line_generic(fd, NULL, NULL, len_p);
}
int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
{
int len = packet_read(fd, NULL, NULL,
packet_buffer, sizeof(packet_buffer),
PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
if (dst_len)
*dst_len = len;
if (dst_line)
*dst_line = (len > 0) ? packet_buffer : NULL;
return len;
}
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);
}
ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
{
int packet_len;
size_t orig_len = sb_out->len;
size_t orig_alloc = sb_out->alloc;
for (;;) {
strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
packet_len = packet_read(fd_in, NULL, NULL,
/* strbuf_grow() above always allocates one extra byte to
* store a '\0' at the end of the string. packet_read()
* writes a '\0' extra byte at the end, too. Let it know
* that there is already room for the extra byte.
*/
sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
PACKET_READ_GENTLE_ON_EOF);
if (packet_len <= 0)
break;
sb_out->len += packet_len;
}
if (packet_len < 0) {
if (orig_alloc == 0)
strbuf_release(sb_out);
else
strbuf_setlen(sb_out, orig_len);
return packet_len;
}
return sb_out->len - orig_len;
}
/* Packet Reader Functions */
void packet_reader_init(struct packet_reader *reader, int fd,
char *src_buffer, size_t src_len,
int options)
{
memset(reader, 0, sizeof(*reader));
reader->fd = fd;
reader->src_buffer = src_buffer;
reader->src_len = src_len;
reader->buffer = packet_buffer;
reader->buffer_size = sizeof(packet_buffer);
reader->options = options;
}
enum packet_read_status packet_reader_read(struct packet_reader *reader)
{
if (reader->line_peeked) {
reader->line_peeked = 0;
return reader->status;
}
reader->status = packet_read_with_status(reader->fd,
&reader->src_buffer,
&reader->src_len,
reader->buffer,
reader->buffer_size,
&reader->pktlen,
reader->options);
if (reader->status == PACKET_READ_NORMAL)
reader->line = reader->buffer;
else
reader->line = NULL;
return reader->status;
}
enum packet_read_status packet_reader_peek(struct packet_reader *reader)
{
/* Only allow peeking a single line */
if (reader->line_peeked)
return reader->status;
/* Peek a line by reading it and setting peeked flag */
packet_reader_read(reader);
reader->line_peeked = 1;
return reader->status;
}