/*

 * Copyright (C) the libgit2 contributors. All rights reserved.

 *

 * 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 "smart.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 and multi_ack_detailed */

static int ack_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_ack *pkt;

	pkt = git__calloc(1, sizeof(git_pkt_ack));

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_ACK;

	if (git__prefixncmp(line, len, "ACK "))

		goto out_err;

	line += 4;

	len -= 4;

	if (len < GIT_OID_HEXSZ || git_oid_fromstr(&pkt->oid, line) < 0)

		goto out_err;

	line += GIT_OID_HEXSZ;

	len -= GIT_OID_HEXSZ;

	if (len && line[0] == ' ') {

		line++;

		len--;

		if (!git__prefixncmp(line, len, "continue"))

			pkt->status = GIT_ACK_CONTINUE;

		else if (!git__prefixncmp(line, len, "common"))

			pkt->status = GIT_ACK_COMMON;

		else if (!git__prefixncmp(line, len, "ready"))

			pkt->status = GIT_ACK_READY;

		else

			goto out_err;

	}

	*out = (git_pkt *) pkt;

	return 0;

out_err:

	giterr_set(GITERR_NET, "error parsing ACK pkt-line");

	git__free(pkt);

	return -1;

}

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 comment_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_comment *pkt;

	size_t alloclen;

	GITERR_CHECK_ALLOC_ADD(&alloclen, sizeof(git_pkt_comment), len);

	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);

	pkt = git__malloc(alloclen);

	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 = NULL;

	size_t alloclen;

	/* Remove "ERR " from the line */

	if (git__prefixncmp(line, len, "ERR "))

		goto out_err;

	line += 4;

	len -= 4;

	GITERR_CHECK_ALLOC_ADD(&alloclen, sizeof(git_pkt_progress), len);

	GITERR_CHECK_ALLOC_ADD(&alloclen, alloclen, 1);

	pkt = git__malloc(alloclen);

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_ERR;

	pkt->len = len;

	memcpy(pkt->error, line, len);

	pkt->error[len] = '\0';

	*out = (git_pkt *) pkt;

	return 0;

out_err:

	giterr_set(GITERR_NET, "error parsing ERR pkt-line");

	git__free(pkt);

	return -1;

}

static int data_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_data *pkt;

	size_t alloclen;

	line++;

	len--;

	GITERR_CHECK_ALLOC_ADD(&alloclen, sizeof(git_pkt_progress), len);

	pkt = git__malloc(alloclen);

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_DATA;

	pkt->len = len;

	memcpy(pkt->data, line, len);

	*out = (git_pkt *) pkt;

	return 0;

}

static int sideband_progress_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_progress *pkt;

	size_t alloclen;

	line++;

	len--;

	GITERR_CHECK_ALLOC_ADD(&alloclen, sizeof(git_pkt_progress), len);

	pkt = git__malloc(alloclen);

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_PROGRESS;

	pkt->len = len;

	memcpy(pkt->data, line, len);

	*out = (git_pkt *) pkt;

	return 0;

}

static int sideband_error_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_err *pkt;

	size_t alloc_len;

	line++;

	len--;

	GITERR_CHECK_ALLOC_ADD(&alloc_len, sizeof(git_pkt_err), len);

	GITERR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 1);

	pkt = git__malloc(alloc_len);

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_ERR;

	pkt->len = (int)len;

	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)

{

	git_pkt_ref *pkt;

	size_t alloclen;

	pkt = git__calloc(1, sizeof(git_pkt_ref));

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_REF;

	if (len < GIT_OID_HEXSZ || git_oid_fromstr(&pkt->head.oid, line) < 0)

		goto out_err;

	line += GIT_OID_HEXSZ;

	len -= GIT_OID_HEXSZ;

	if (git__prefixncmp(line, len, " "))

		goto out_err;

	line++;

	len--;

	if (!len)

		goto out_err;

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

		--len;

	GITERR_CHECK_ALLOC_ADD(&alloclen, len, 1);

	pkt->head.name = git__malloc(alloclen);

	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;

out_err:

	giterr_set(GITERR_NET, "error parsing REF pkt-line");

	if (pkt)

		git__free(pkt->head.name);

	git__free(pkt);

	return -1;

}

static int ok_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_ok *pkt;

	size_t alloc_len;

	pkt = git__malloc(sizeof(*pkt));

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_OK;

	if (git__prefixncmp(line, len, "ok "))

		goto out_err;

	line += 3;

	len -= 3;

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

		--len;

	GITERR_CHECK_ALLOC_ADD(&alloc_len, len, 1);

	pkt->ref = git__malloc(alloc_len);

	GITERR_CHECK_ALLOC(pkt->ref);

	memcpy(pkt->ref, line, len);

	pkt->ref[len] = '\0';

	*out = (git_pkt *)pkt;

	return 0;

out_err:

	giterr_set(GITERR_NET, "error parsing OK pkt-line");

	git__free(pkt);

	return -1;

}

static int ng_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_ng *pkt;

	const char *ptr, *eol;

	size_t alloclen;

	pkt = git__malloc(sizeof(*pkt));

	GITERR_CHECK_ALLOC(pkt);

	pkt->ref = NULL;

	pkt->type = GIT_PKT_NG;

	eol = line + len;

	if (git__prefixncmp(line, len, "ng "))

		goto out_err;

	line += 3;

	if (!(ptr = memchr(line, ' ', eol - line)))

		goto out_err;

	len = ptr - line;

	GITERR_CHECK_ALLOC_ADD(&alloclen, len, 1);

	pkt->ref = git__malloc(alloclen);

	GITERR_CHECK_ALLOC(pkt->ref);

	memcpy(pkt->ref, line, len);

	pkt->ref[len] = '\0';

	line = ptr + 1;

	if (line >= eol)

		goto out_err;

	if (!(ptr = memchr(line, '\n', eol - line)))

		goto out_err;

	len = ptr - line;

	GITERR_CHECK_ALLOC_ADD(&alloclen, len, 1);

	pkt->msg = git__malloc(alloclen);

	GITERR_CHECK_ALLOC(pkt->msg);

	memcpy(pkt->msg, line, len);

	pkt->msg[len] = '\0';

	*out = (git_pkt *)pkt;

	return 0;

out_err:

	giterr_set(GITERR_NET, "invalid packet line");

	git__free(pkt->ref);

	git__free(pkt);

	return -1;

}

static int unpack_pkt(git_pkt **out, const char *line, size_t len)

{

	git_pkt_unpack *pkt;

	pkt = git__malloc(sizeof(*pkt));

	GITERR_CHECK_ALLOC(pkt);

	pkt->type = GIT_PKT_UNPACK;

	if (!git__prefixncmp(line, len, "unpack ok"))

		pkt->unpack_ok = 1;

	else

		pkt->unpack_ok = 0;

	*out = (git_pkt *)pkt;

	return 0;

}

static int parse_len(size_t *out, const char *line, size_t linelen)

{

	char num[PKT_LEN_SIZE + 1];

	int i, k, error;

	int32_t len;

	const char *num_end;

	/* Not even enough for the length */

	if (linelen < PKT_LEN_SIZE)

		return GIT_EBUFS;

	memcpy(num, line, PKT_LEN_SIZE);

	num[PKT_LEN_SIZE] = '\0';

	for (i = 0; i < PKT_LEN_SIZE; ++i) {

		if (!isxdigit(num[i])) {

			/* Make sure there are no special characters before passing to error message */

			for (k = 0; k < PKT_LEN_SIZE; ++k) {

				if(!isprint(num[k])) {

					num[k] = '.';

				}

			}

			giterr_set(GITERR_NET, "invalid hex digit in length: '%s'", num);

			return -1;

		}

	}

	if ((error = git__strntol32(&len, num, PKT_LEN_SIZE, &num_end, 16)) < 0)

		return error;

	if (len < 0)

		return -1;

	*out = (size_t) len;

	return 0;

}

/*

 * 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 **pkt, const char **endptr, const char *line, size_t linelen)

{

	int error;

	size_t len;

	if ((error = parse_len(&len, line, linelen)) < 0) {

		/*

		 * If we fail to parse the length, it might be

		 * because the server is trying to send us the

		 * packfile already or because we do not yet have

		 * enough data.

		 */

		if (error == GIT_EBUFS)

			;

		else if (!git__prefixncmp(line, linelen, "PACK"))

			giterr_set(GITERR_NET, "unexpected pack file");

		else

			giterr_set(GITERR_NET, "bad packet length");

		return error;

	}

	/*

	 * Make sure there is enough in the buffer to satisfy

	 * this line.

	 */

	if (linelen < len)

		return GIT_EBUFS;

	/*

	 * The length has to be exactly 0 in case of a flush

	 * packet or greater than PKT_LEN_SIZE, as the decoded

	 * length includes its own encoded length of four bytes.

	 */

	if (len != 0 && len < PKT_LEN_SIZE)

		return GIT_ERROR;

	line += PKT_LEN_SIZE;

	/*

	 * The Git protocol does not specify empty lines as part

	 * of the protocol. Not knowing what to do with an empty

	 * line, we should return an error upon hitting one.

	 */

	if (len == PKT_LEN_SIZE) {

		giterr_set_str(GITERR_NET, "Invalid empty packet");

		return GIT_ERROR;

	}

	if (len == 0) { /* Flush pkt */

		*endptr = line;

		return flush_pkt(pkt);

	}

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

	if (*line == GIT_SIDE_BAND_DATA)

		error = data_pkt(pkt, line, len);

	else if (*line == GIT_SIDE_BAND_PROGRESS)

		error = sideband_progress_pkt(pkt, line, len);

	else if (*line == GIT_SIDE_BAND_ERROR)

		error = sideband_error_pkt(pkt, line, len);

	else if (!git__prefixncmp(line, len, "ACK"))

		error = ack_pkt(pkt, line, len);

	else if (!git__prefixncmp(line, len, "NAK"))

		error = nak_pkt(pkt);

	else if (!git__prefixncmp(line, len, "ERR"))

		error = err_pkt(pkt, line, len);

	else if (*line == '#')

		error = comment_pkt(pkt, line, len);

	else if (!git__prefixncmp(line, len, "ok"))

		error = ok_pkt(pkt, line, len);

	else if (!git__prefixncmp(line, len, "ng"))

		error = ng_pkt(pkt, line, len);

	else if (!git__prefixncmp(line, len, "unpack"))

		error = unpack_pkt(pkt, line, len);

	else

		error = ref_pkt(pkt, line, len);

	*endptr = line + len;

	return error;

}

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(p->head.symref_target);

	}

	if (pkt->type == GIT_PKT_OK) {

		git_pkt_ok *p = (git_pkt_ok *) pkt;

		git__free(p->ref);

	}

	if (pkt->type == GIT_PKT_NG) {

		git_pkt_ng *p = (git_pkt_ng *) pkt;

		git__free(p->ref);

		git__free(p->msg);

	}

	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(const git_remote_head *head, transport_smart_caps *caps, git_buf *buf)

{

	git_buf str = GIT_BUF_INIT;

	char oid[GIT_OID_HEXSZ +1] = {0};

	size_t len;

	/* Prefer multi_ack_detailed */

	if (caps->multi_ack_detailed)

		git_buf_puts(&str, GIT_CAP_MULTI_ACK_DETAILED " ");

	else if (caps->multi_ack)

		git_buf_puts(&str, GIT_CAP_MULTI_ACK " ");

	/* Prefer side-band-64k if the server supports both */

	if (caps->side_band_64k)

		git_buf_printf(&str, "%s ", GIT_CAP_SIDE_BAND_64K);

	else if (caps->side_band)

		git_buf_printf(&str, "%s ", GIT_CAP_SIDE_BAND);

	if (caps->include_tag)

		git_buf_puts(&str, GIT_CAP_INCLUDE_TAG " ");

	if (caps->thin_pack)

		git_buf_puts(&str, GIT_CAP_THIN_PACK " ");

	if (caps->ofs_delta)

		git_buf_puts(&str, GIT_CAP_OFS_DELTA " ");

	if (git_buf_oom(&str))

		return -1;

	len = strlen("XXXXwant ") + GIT_OID_HEXSZ + 1 /* NUL */ +

		 git_buf_len(&str) + 1 /* LF */;

	if (len > 0xffff) {

		giterr_set(GITERR_NET,

			"tried to produce packet with invalid length %" PRIuZ, len);

		return -1;

	}

	git_buf_grow_by(buf, len);

	git_oid_fmt(oid, &head->oid);

	git_buf_printf(buf,

		"%04xwant %s %s\n", (unsigned int)len, oid, git_buf_cstr(&str);;

	git_buf_free(&str);

	GITERR_CHECK_ALLOC_BUF(buf);

	return 0;

}

/*

 * 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_remote_head * const *refs,

	size_t count,

	transport_smart_caps *caps,

	git_buf *buf)

{

	size_t i = 0;

	const git_remote_head *head;

	if (caps->common) {

		for (; i < count; ++i) {

			head = refs[i];

			if (!head->local)

				break;

		}

		if (buffer_want_with_caps(refs[i], caps, buf) < 0)

			return -1;

		i++;

	}

	for (; i < count; ++i) {

		char oid[GIT_OID_HEXSZ];

		head = refs[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);

}