src/pkt.c - third_party/libgit2 - Git at Google

 /*
  * Copyright (C) 2009-2012 the libgit2 contributors
  *
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */

 #include "common.h"

 #include "git2/types.h"
 #include "git2/errors.h"
 #include "git2/refs.h"
 #include "git2/revwalk.h"

 #include "pkt.h"
 #include "util.h"
 #include "netops.h"
 #include "posix.h"
 #include "buffer.h"

 #include <ctype.h>

 #define PKT_LEN_SIZE 4
 static const char pkt_done_str[] = "0009done\n";
 static const char pkt_flush_str[] = "0000";
 static const char pkt_have_prefix[] = "0032have ";
 static const char pkt_want_prefix[] = "0032want ";

 static int flush_pkt(git_pkt **out)
 {
 	git_pkt *pkt;

 	pkt = git__malloc(sizeof(git_pkt));
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_FLUSH;
 	*out = pkt;

 	return 0;
 }

 /* the rest of the line will be useful for multi_ack */
 static int ack_pkt(git_pkt **out, const char *line, size_t len)
 {
 	git_pkt *pkt;
 	GIT_UNUSED(line);
 	GIT_UNUSED(len);

 	pkt = git__malloc(sizeof(git_pkt));
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_ACK;
 	*out = pkt;

 	return 0;
 }

 static int nak_pkt(git_pkt **out)
 {
 	git_pkt *pkt;

 	pkt = git__malloc(sizeof(git_pkt));
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_NAK;
 	*out = pkt;

 	return 0;
 }

 static int pack_pkt(git_pkt **out)
 {
 	git_pkt *pkt;

 	pkt = git__malloc(sizeof(git_pkt));
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_PACK;
 	*out = pkt;

 	return 0;
 }

 static int comment_pkt(git_pkt **out, const char *line, size_t len)
 {
 	git_pkt_comment *pkt;

 	pkt = git__malloc(sizeof(git_pkt_comment) + len + 1);
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_COMMENT;
 	memcpy(pkt->comment, line, len);
 	pkt->comment[len] = '\0';

 	*out = (git_pkt *) pkt;

 	return 0;
 }

 static int err_pkt(git_pkt **out, const char *line, size_t len)
 {
 	git_pkt_err *pkt;

 	/* Remove "ERR " from the line */
 	line += 4;
 	len -= 4;
 	pkt = git__malloc(sizeof(git_pkt_err) + len + 1);
 	GITERR_CHECK_ALLOC(pkt);

 	pkt->type = GIT_PKT_ERR;
 	memcpy(pkt->error, line, len);
 	pkt->error[len] = '\0';

 	*out = (git_pkt *) pkt;

 	return 0;
 }

 /*
  * Parse an other-ref line.
  */
 static int ref_pkt(git_pkt **out, const char *line, size_t len)
 {
 	int error;
 	git_pkt_ref *pkt;

 	pkt = git__malloc(sizeof(git_pkt_ref));
 	GITERR_CHECK_ALLOC(pkt);

 	memset(pkt, 0x0, sizeof(git_pkt_ref));
 	pkt->type = GIT_PKT_REF;
 	if ((error = git_oid_fromstr(&pkt->head.oid, line)) < 0)
 		goto error_out;

 	/* Check for a bit of consistency */
 	if (line[GIT_OID_HEXSZ] != ' ') {
 		giterr_set(GITERR_NET, "Error parsing pkt-line");
 		error = -1;
 		goto error_out;
 	}

 	/* Jump from the name */
 	line += GIT_OID_HEXSZ + 1;
 	len -= (GIT_OID_HEXSZ + 1);

 	if (line[len - 1] == '\n')
 		--len;

 	pkt->head.name = git__malloc(len + 1);
 	GITERR_CHECK_ALLOC(pkt->head.name);

 	memcpy(pkt->head.name, line, len);
 	pkt->head.name[len] = '\0';

 	if (strlen(pkt->head.name) < len) {
 		pkt->capabilities = strchr(pkt->head.name, '\0') + 1;
 	}

 	*out = (git_pkt *)pkt;
 	return 0;

 error_out:
 	git__free(pkt);
 	return error;
 }

 static int32_t parse_len(const char *line)
 {
 	char num[PKT_LEN_SIZE + 1];
 	int i, error;
 	int32_t len;
 	const char *num_end;

 	memcpy(num, line, PKT_LEN_SIZE);
 	num[PKT_LEN_SIZE] = '\0';

 	for (i = 0; i < PKT_LEN_SIZE; ++i) {
 		if (!isxdigit(num[i])) {
 			giterr_set(GITERR_NET, "Found invalid hex digit in length");
 			return -1;
 		}
 	}

 	if ((error = git__strtol32(&len, num, &num_end, 16)) < 0)
 		return error;

 	return len;
 }

 /*
  * As per the documentation, the syntax is:
  *
  * pkt-line	= data-pkt / flush-pkt
  * data-pkt	= pkt-len pkt-payload
  * pkt-len		= 4*(HEXDIG)
  * pkt-payload = (pkt-len -4)*(OCTET)
  * flush-pkt	= "0000"
  *
  * Which means that the first four bytes are the length of the line,
  * in ASCII hexadecimal (including itself)
  */

 int git_pkt_parse_line(
 	git_pkt **head, const char *line, const char **out, size_t bufflen)
 {
 	int ret;
 	int32_t len;

 	/* Not even enough for the length */
 	if (bufflen > 0 && bufflen < PKT_LEN_SIZE)
 		return GIT_EBUFS;

 	len = parse_len(line);
 	if (len < 0) {
 		/*
 		 * If we fail to parse the length, it might be because the
 		 * server is trying to send us the packfile already.
 		 */
 		if (bufflen >= 4 && !git__prefixcmp(line, "PACK")) {
 			giterr_clear();
 			*out = line;
 			return pack_pkt(head);
 		}

 		return (int)len;
 	}

 	/*
 	 * If we were given a buffer length, then make sure there is
 	 * enough in the buffer to satisfy this line
 	 */
 	if (bufflen > 0 && bufflen < (size_t)len)
 		return GIT_EBUFS;

 	line += PKT_LEN_SIZE;
 	/*
 	 * TODO: How do we deal with empty lines? Try again? with the next
 	 * line?
 	 */
 	if (len == PKT_LEN_SIZE) {
 		*out = line;
 		return 0;
 	}

 	if (len == 0) { /* Flush pkt */
 		*out = line;
 		return flush_pkt(head);
 	}

 	len -= PKT_LEN_SIZE; /* the encoded length includes its own size */

 	/* Assming the minimal size is actually 4 */
 	if (!git__prefixcmp(line, "ACK"))
 		ret = ack_pkt(head, line, len);
 	else if (!git__prefixcmp(line, "NAK"))
 		ret = nak_pkt(head);
 	else if (!git__prefixcmp(line, "ERR "))
 		ret = err_pkt(head, line, len);
 	else if (*line == '#')
 		ret = comment_pkt(head, line, len);
 	else
 		ret = ref_pkt(head, line, len);

 	*out = line + len;

 	return ret;
 }

 void git_pkt_free(git_pkt *pkt)
 {
 	if (pkt->type == GIT_PKT_REF) {
 		git_pkt_ref *p = (git_pkt_ref *) pkt;
 		git__free(p->head.name);
 	}

 	git__free(pkt);
 }

 int git_pkt_buffer_flush(git_buf *buf)
 {
 	return git_buf_put(buf, pkt_flush_str, strlen(pkt_flush_str));
 }

 static int buffer_want_with_caps(git_remote_head *head, git_transport_caps *caps, git_buf *buf)
 {
 	char capstr[20];
 	char oid[GIT_OID_HEXSZ +1] = {0};
 	unsigned int len;

 	if (caps->ofs_delta)
 		strncpy(capstr, GIT_CAP_OFS_DELTA, sizeof(capstr));

 	len = (unsigned int)
 		(strlen("XXXXwant ") + GIT_OID_HEXSZ + 1 /* NUL */ +
 		 strlen(capstr) + 1 /* LF */);
 	git_buf_grow(buf, git_buf_len(buf) + len);

 	git_oid_fmt(oid, &head->oid);
 	return git_buf_printf(buf, "%04xwant %s%c%s\n", len, oid, 0, capstr);
 }

 /*
  * All "want" packets have the same length and format, so what we do
  * is overwrite the OID each time.
  */

 int git_pkt_buffer_wants(const git_vector *refs, git_transport_caps *caps, git_buf *buf)
 {
 	unsigned int i = 0;
 	git_remote_head *head;

 	if (caps->common) {
 		for (; i < refs->length; ++i) {
 			head = refs->contents[i];
 			if (!head->local)
 				break;
 		}

 		if (buffer_want_with_caps(refs->contents[i], caps, buf) < 0)
 			return -1;

 		i++;
 	}

 	for (; i < refs->length; ++i) {
 		char oid[GIT_OID_HEXSZ];

 		head = refs->contents[i];
 		if (head->local)
 			continue;

 		git_oid_fmt(oid, &head->oid);
 		git_buf_put(buf, pkt_want_prefix, strlen(pkt_want_prefix));
 		git_buf_put(buf, oid, GIT_OID_HEXSZ);
 		git_buf_putc(buf, '\n');
 		if (git_buf_oom(buf))
 			return -1;
 	}

 	return git_pkt_buffer_flush(buf);
 }

 int git_pkt_buffer_have(git_oid *oid, git_buf *buf)
 {
 	char oidhex[GIT_OID_HEXSZ + 1];

 	memset(oidhex, 0x0, sizeof(oidhex));
 	git_oid_fmt(oidhex, oid);
 	return git_buf_printf(buf, "%s%s\n", pkt_have_prefix, oidhex);
 }

 int git_pkt_buffer_done(git_buf *buf)
 {
 	return git_buf_puts(buf, pkt_done_str);
 }
	/*
	* Copyright (C) 2009-2012 the libgit2 contributors
	*
	* This file is part of libgit2, distributed under the GNU GPL v2 with
	* a Linking Exception. For full terms see the included COPYING file.
	*/

	#include "common.h"

	#include "git2/types.h"
	#include "git2/errors.h"
	#include "git2/refs.h"
	#include "git2/revwalk.h"

	#include "pkt.h"
	#include "util.h"
	#include "netops.h"
	#include "posix.h"
	#include "buffer.h"

	#include <ctype.h>

	#define PKT_LEN_SIZE 4
	static const char pkt_done_str[] = "0009done\n";
	static const char pkt_flush_str[] = "0000";
	static const char pkt_have_prefix[] = "0032have ";
	static const char pkt_want_prefix[] = "0032want ";

	static int flush_pkt(git_pkt **out)
	{
	git_pkt *pkt;

	pkt = git__malloc(sizeof(git_pkt));
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_FLUSH;
	*out = pkt;

	return 0;
	}

	/* the rest of the line will be useful for multi_ack */
	static int ack_pkt(git_pkt *out, const char line, size_t len)
	{
	git_pkt *pkt;
	GIT_UNUSED(line);
	GIT_UNUSED(len);

	pkt = git__malloc(sizeof(git_pkt));
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_ACK;
	*out = pkt;

	return 0;
	}

	static int nak_pkt(git_pkt **out)
	{
	git_pkt *pkt;

	pkt = git__malloc(sizeof(git_pkt));
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_NAK;
	*out = pkt;

	return 0;
	}

	static int pack_pkt(git_pkt **out)
	{
	git_pkt *pkt;

	pkt = git__malloc(sizeof(git_pkt));
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_PACK;
	*out = pkt;

	return 0;
	}

	static int comment_pkt(git_pkt *out, const char line, size_t len)
	{
	git_pkt_comment *pkt;

	pkt = git__malloc(sizeof(git_pkt_comment) + len + 1);
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_COMMENT;
	memcpy(pkt->comment, line, len);
	pkt->comment[len] = '\0';

	out = (git_pkt ) pkt;

	return 0;
	}

	static int err_pkt(git_pkt *out, const char line, size_t len)
	{
	git_pkt_err *pkt;

	/* Remove "ERR " from the line */
	line += 4;
	len -= 4;
	pkt = git__malloc(sizeof(git_pkt_err) + len + 1);
	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_ERR;
	memcpy(pkt->error, line, len);
	pkt->error[len] = '\0';

	out = (git_pkt ) pkt;

	return 0;
	}

	/*
	* Parse an other-ref line.
	*/
	static int ref_pkt(git_pkt *out, const char line, size_t len)
	{
	int error;
	git_pkt_ref *pkt;

	pkt = git__malloc(sizeof(git_pkt_ref));
	GITERR_CHECK_ALLOC(pkt);

	memset(pkt, 0x0, sizeof(git_pkt_ref));
	pkt->type = GIT_PKT_REF;
	if ((error = git_oid_fromstr(&pkt->head.oid, line)) < 0)
	goto error_out;

	/* Check for a bit of consistency */
	if (line[GIT_OID_HEXSZ] != ' ') {
	giterr_set(GITERR_NET, "Error parsing pkt-line");
	error = -1;
	goto error_out;
	}

	/* Jump from the name */
	line += GIT_OID_HEXSZ + 1;
	len -= (GIT_OID_HEXSZ + 1);

	if (line[len - 1] == '\n')
	--len;

	pkt->head.name = git__malloc(len + 1);
	GITERR_CHECK_ALLOC(pkt->head.name);

	memcpy(pkt->head.name, line, len);
	pkt->head.name[len] = '\0';

	if (strlen(pkt->head.name) < len) {
	pkt->capabilities = strchr(pkt->head.name, '\0') + 1;
	}

	out = (git_pkt )pkt;
	return 0;

	error_out:
	git__free(pkt);
	return error;
	}

	static int32_t parse_len(const char *line)
	{
	char num[PKT_LEN_SIZE + 1];
	int i, error;
	int32_t len;
	const char *num_end;

	memcpy(num, line, PKT_LEN_SIZE);
	num[PKT_LEN_SIZE] = '\0';

	for (i = 0; i < PKT_LEN_SIZE; ++i) {
	if (!isxdigit(num[i])) {
	giterr_set(GITERR_NET, "Found invalid hex digit in length");
	return -1;
	}
	}

	if ((error = git__strtol32(&len, num, &num_end, 16)) < 0)
	return error;

	return len;
	}

	/*
	* As per the documentation, the syntax is:
	*
	* pkt-line = data-pkt / flush-pkt
	* data-pkt = pkt-len pkt-payload
	* pkt-len = 4*(HEXDIG)
	* pkt-payload = (pkt-len -4)*(OCTET)
	* flush-pkt = "0000"
	*
	* Which means that the first four bytes are the length of the line,
	* in ASCII hexadecimal (including itself)
	*/

	int git_pkt_parse_line(
	git_pkt *head, const char line, const char **out, size_t bufflen)
	{
	int ret;
	int32_t len;

	/* Not even enough for the length */
	if (bufflen > 0 && bufflen < PKT_LEN_SIZE)
	return GIT_EBUFS;

	len = parse_len(line);
	if (len < 0) {
	/*
	* If we fail to parse the length, it might be because the
	* server is trying to send us the packfile already.
	*/
	if (bufflen >= 4 && !git__prefixcmp(line, "PACK")) {
	giterr_clear();
	*out = line;
	return pack_pkt(head);
	}

	return (int)len;
	}

	/*
	* If we were given a buffer length, then make sure there is
	* enough in the buffer to satisfy this line
	*/
	if (bufflen > 0 && bufflen < (size_t)len)
	return GIT_EBUFS;

	line += PKT_LEN_SIZE;
	/*
	* TODO: How do we deal with empty lines? Try again? with the next
	* line?
	*/
	if (len == PKT_LEN_SIZE) {
	*out = line;
	return 0;
	}

	if (len == 0) { /* Flush pkt */
	*out = line;
	return flush_pkt(head);
	}

	len -= PKT_LEN_SIZE; /* the encoded length includes its own size */

	/* Assming the minimal size is actually 4 */
	if (!git__prefixcmp(line, "ACK"))
	ret = ack_pkt(head, line, len);
	else if (!git__prefixcmp(line, "NAK"))
	ret = nak_pkt(head);
	else if (!git__prefixcmp(line, "ERR "))
	ret = err_pkt(head, line, len);
	else if (*line == '#')
	ret = comment_pkt(head, line, len);
	else
	ret = ref_pkt(head, line, len);

	*out = line + len;

	return ret;
	}

	void git_pkt_free(git_pkt *pkt)
	{
	if (pkt->type == GIT_PKT_REF) {
	git_pkt_ref p = (git_pkt_ref ) pkt;
	git__free(p->head.name);
	}

	git__free(pkt);
	}

	int git_pkt_buffer_flush(git_buf *buf)
	{
	return git_buf_put(buf, pkt_flush_str, strlen(pkt_flush_str));
	}

	static int buffer_want_with_caps(git_remote_head head, git_transport_caps caps, git_buf *buf)
	{
	char capstr[20];
	char oid[GIT_OID_HEXSZ +1] = {0};
	unsigned int len;

	if (caps->ofs_delta)
	strncpy(capstr, GIT_CAP_OFS_DELTA, sizeof(capstr));

	len = (unsigned int)
	(strlen("XXXXwant ") + GIT_OID_HEXSZ + 1 /* NUL */ +
	strlen(capstr) + 1 /* LF */);
	git_buf_grow(buf, git_buf_len(buf) + len);

	git_oid_fmt(oid, &head->oid);
	return git_buf_printf(buf, "%04xwant %s%c%s\n", len, oid, 0, capstr);
	}

	/*
	* All "want" packets have the same length and format, so what we do
	* is overwrite the OID each time.
	*/

	int git_pkt_buffer_wants(const git_vector refs, git_transport_caps caps, git_buf *buf)
	{
	unsigned int i = 0;
	git_remote_head *head;

	if (caps->common) {
	for (; i < refs->length; ++i) {
	head = refs->contents[i];
	if (!head->local)
	break;
	}

	if (buffer_want_with_caps(refs->contents[i], caps, buf) < 0)
	return -1;

	i++;
	}

	for (; i < refs->length; ++i) {
	char oid[GIT_OID_HEXSZ];

	head = refs->contents[i];
	if (head->local)
	continue;

	git_oid_fmt(oid, &head->oid);
	git_buf_put(buf, pkt_want_prefix, strlen(pkt_want_prefix));
	git_buf_put(buf, oid, GIT_OID_HEXSZ);
	git_buf_putc(buf, '\n');
	if (git_buf_oom(buf))
	return -1;
	}

	return git_pkt_buffer_flush(buf);
	}

	int git_pkt_buffer_have(git_oid oid, git_buf buf)
	{
	char oidhex[GIT_OID_HEXSZ + 1];

	memset(oidhex, 0x0, sizeof(oidhex));
	git_oid_fmt(oidhex, oid);
	return git_buf_printf(buf, "%s%s\n", pkt_have_prefix, oidhex);
	}

	int git_pkt_buffer_done(git_buf *buf)
	{
	return git_buf_puts(buf, pkt_done_str);
	}