thodg/got/lib/pkt.c

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• Hash : f024663d
  Author :
  Date : 2021-09-05T13:50:39
  

  move pkt code used by got-fetch-pack and got-send-pack to a common file The Git protocol uses a simple packet framing format. The got-fetch-pack and got-send-pack programs contained identical copies of functions to support this format. Move related functions to new file lib/pkt.c and link both programs against this common implementation. No functional change.

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• lib/pkt.c

• /*
   * Copyright (c) 2019 Ori Bernstein <ori@openbsd.org>
   * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <ctype.h>
  #include <errno.h>
  #include <limits.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  
  #include "got_error.h"
  
  const struct got_error *
  got_pkt_readn(ssize_t *off, int fd, void *buf, size_t n)
  {
  	ssize_t r;
  
  	*off = 0;
  	while (*off != n) {
  		r = read(fd, buf + *off, n - *off);
  		if (r == -1)
  			return got_error_from_errno("read");
  		if (r == 0)
  			return NULL;
  		*off += r;
  	}
  	return NULL;
  }
  
  const struct got_error *
  got_pkt_flushpkt(int fd, int chattygot)
  {
  	ssize_t w;
  
  	if (chattygot > 1)
  		fprintf(stderr, "%s: writepkt: 0000\n", getprogname());
  
  	w = write(fd, "0000", 4);
  	if (w == -1)
  		return got_error_from_errno("write");
  	if (w != 4)
  		return got_error(GOT_ERR_IO);
  	return NULL;
  }
  
  /*
   * Packet header contains a 4-byte hexstring which specifies the length
   * of data which follows.
   */
  const struct got_error *
  got_pkt_readhdr(int *datalen, int fd, int chattygot)
  {
  	static const struct got_error *err = NULL;
  	char lenstr[5];
  	long len;
  	char *e;
  	int n, i;
  	ssize_t r;
  
  	*datalen = 0;
  
  	err = got_pkt_readn(&r, fd, lenstr, 4);
  	if (err)
  		return err;
  	if (r == 0) {
  		/* implicit "0000" */
  		if (chattygot > 1)
  			fprintf(stderr, "%s: readpkt: 0000\n", getprogname());
  		return NULL;
  	}
  	if (r != 4)
  		return got_error_msg(GOT_ERR_BAD_PACKET,
  		    "wrong packet header length");
  
  	lenstr[4] = '\0';
  	for (i = 0; i < 4; i++) {
  		if (!isprint((unsigned char)lenstr[i]))
  			return got_error_msg(GOT_ERR_BAD_PACKET,
  			    "unprintable character in packet length field");
  	}
  	for (i = 0; i < 4; i++) {
  		if (!isxdigit((unsigned char)lenstr[i])) {
  			if (chattygot)
  				fprintf(stderr, "%s: bad length: '%s'\n",
  				    getprogname(), lenstr);
  			return got_error_msg(GOT_ERR_BAD_PACKET,
  			    "packet length not specified in hex");
  		}
  	}
  	errno = 0;
  	len = strtol(lenstr, &e, 16);
  	if (lenstr[0] == '\0' || *e != '\0')
  		return got_error(GOT_ERR_BAD_PACKET);
  	if (errno == ERANGE && (len == LONG_MAX || len == LONG_MIN))
  		return got_error_msg(GOT_ERR_BAD_PACKET, "bad packet length");
  	if (len > INT_MAX || len < INT_MIN)
  		return got_error_msg(GOT_ERR_BAD_PACKET, "bad packet length");
  	n = len;
  	if (n == 0)
  		return NULL;
  	if (n <= 4)
  		return got_error_msg(GOT_ERR_BAD_PACKET, "packet too short");
  	n  -= 4;
  
  	*datalen = n;
  	return NULL;
  }
  
  const struct got_error *
  got_pkt_readpkt(int *outlen, int fd, char *buf, int buflen, int chattygot)
  {
  	const struct got_error *err = NULL;
  	int datalen, i;
  	ssize_t n;
  
  	err = got_pkt_readhdr(&datalen, fd, chattygot);
  	if (err)
  		return err;
  
  	if (datalen > buflen)
  		return got_error(GOT_ERR_NO_SPACE);
  
  	err = got_pkt_readn(&n, fd, buf, datalen);
  	if (err)
  		return err;
  	if (n != datalen)
  		return got_error_msg(GOT_ERR_BAD_PACKET, "short packet");
  
  	if (chattygot > 1) {
  		fprintf(stderr, "%s: readpkt: %zd:\t", getprogname(), n);
  		for (i = 0; i < n; i++) {
  			if (isprint(buf[i]))
  				fputc(buf[i], stderr);
  			else
  				fprintf(stderr, "[0x%.2x]", buf[i]);
  		}
  		fputc('\n', stderr);
  	}
  
  	*outlen = n;
  	return NULL;
  }
  
  const struct got_error *
  got_pkt_writepkt(int fd, char *buf, int nbuf, int chattygot)
  {
  	char len[5];
  	int i;
  	ssize_t w;
  
  	if (snprintf(len, sizeof(len), "%04x", nbuf + 4) >= sizeof(len))
  		return got_error(GOT_ERR_NO_SPACE);
  	w = write(fd, len, 4);
  	if (w == -1)
  		return got_error_from_errno("write");
  	if (w != 4)
  		return got_error(GOT_ERR_IO);
  	w = write(fd, buf, nbuf);
  	if (w == -1)
  		return got_error_from_errno("write");
  	if (w != nbuf)
  		return got_error(GOT_ERR_IO);
  	if (chattygot > 1) {
  		fprintf(stderr, "%s: writepkt: %s:\t", getprogname(), len);
  		for (i = 0; i < nbuf; i++) {
  			if (isprint(buf[i]))
  				fputc(buf[i], stderr);
  			else
  				fprintf(stderr, "[0x%.2x]", buf[i]);
  		}
  		fputc('\n', stderr);
  	}
  	return NULL;
  }
  

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