pkt-line.c - jrn/git - Git at Google

 #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);
 }

 int packet_flush_gently(int fd)
 {
 	packet_trace("0000", 4, 1);
 	if (write_in_full(fd, "0000", 4) == 4)
 		return 0;
 	return error("flush packet write failed");
 }

 void packet_buf_flush(struct strbuf *buf)
 {
 	packet_trace("0000", 4, 1);
 	strbuf_add(buf, "0000", 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)
 {
 	struct strbuf buf = STRBUF_INIT;
 	ssize_t count;

 	format_packet(&buf, fmt, args);
 	count = write_in_full(fd, buf.buf, buf.len);
 	if (count == buf.len)
 		return 0;

 	if (!gently) {
 		check_pipe(errno);
 		die_errno("packet write with format failed");
 	}
 	return error("packet write with format failed");
 }

 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) == packet_size)
 		return 0;
 	return error("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);
 }

 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);
 }

 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);
 }

 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;
 }
	#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);
	}

	int packet_flush_gently(int fd)
	{
	packet_trace("0000", 4, 1);
	if (write_in_full(fd, "0000", 4) == 4)
	return 0;
	return error("flush packet write failed");
	}

	void packet_buf_flush(struct strbuf *buf)
	{
	packet_trace("0000", 4, 1);
	strbuf_add(buf, "0000", 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)
	{
	struct strbuf buf = STRBUF_INIT;
	ssize_t count;

	format_packet(&buf, fmt, args);
	count = write_in_full(fd, buf.buf, buf.len);
	if (count == buf.len)
	return 0;

	if (!gently) {
	check_pipe(errno);
	die_errno("packet write with format failed");
	}
	return error("packet write with format failed");
	}

	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) == packet_size)
	return 0;
	return error("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);
	}

	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);
	}

	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);
	}

	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;
	}