IABSD.fr/src/usr.sbin/installboot/util.c

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• Author : deraadt
  Date : 2019-07-03 03:24:01
  Hash : 515e489c
  Message : snprintf/vsnprintf return < 0 on error, rather than -1.

• usr.sbin/installboot/util.c

• /*	$OpenBSD: util.c,v 1.14 2019/07/03 03:24:03 deraadt Exp $	*/
  
  /*
   * Copyright (c) 2014 Joel Sing <jsing@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 <sys/stat.h>
  #include <err.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <limits.h>
  #include <libgen.h>
  
  #include "installboot.h"
  
  #define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
  
  #define BUFSIZE 512
  
  int
  filecopy(const char *srcfile, const char *dstfile)
  {
  	struct stat sb;
  	ssize_t sz, n;
  	int sfd, dfd;
  	char *buf;
  
  	sfd = open(srcfile, O_RDONLY);
  	if (sfd == -1) {
  		warn("open %s", srcfile);
  		return (-1);
  	}
  	if (fstat(sfd, &sb) == -1) {
  		warn("fstat");
  		return (-1);
  	}
  	sz = sb.st_size;
  
  	dfd = open(dstfile, O_WRONLY|O_CREAT);
  	if (dfd == -1) {
  		warn("open %s", dstfile);
  		return (-1);
  	}
  	if (fchown(dfd, 0, 0) == -1)
  		if (errno != EINVAL) {
  			warn("chown");
  			return (-1);
  		}
  	if (fchmod(dfd, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) == -1) {
  		warn("chmod");
  		return (-1);
  	}
  
  	if ((buf = malloc(BUFSIZE)) == NULL) {
  		warn("malloc");
  		return (-1);
  	}
  
  	while (sz > 0) {
  		n = MINIMUM(sz, BUFSIZE);
  		if ((n = read(sfd, buf, n)) == -1) {
  			warn("read");
  			free(buf);
  			return (-1);
  		}
  		sz -= n;
  		if (write(dfd, buf, n) != n) {
  			warn("write");
  			free(buf);
  			return (-1);
  		}
  	}
  
  	ftruncate(dfd, sb.st_size);
  
  	close(dfd);
  	close(sfd);
  	free(buf);
  
  	return (0);
  }
  
  char *
  fileprefix(const char *base, const char *path)
  {
  	char *r = NULL, *d, *b, *s;
  	int n;
  
  	if ((s = malloc(PATH_MAX)) == NULL) {
  		warn("malloc");
  		return (NULL);
  	}
  	n = snprintf(s, PATH_MAX, "%s/%s", base, path);
  	if (n < 0 || n >= PATH_MAX) {
  		warn("snprintf");
  		goto err;
  	}
  	if ((d = dirname(s)) == NULL) {
  		warn("dirname");
  		goto err;
  	}
  	if ((r = realpath(d, NULL)) == NULL) {
  		warn("realpath");
  		goto err;
  	}
  	if ((b = basename(s)) == NULL) {
  		warn("basename");
  		goto err;
  	}
  	n = snprintf(s, PATH_MAX, "%s/%s", r, b);
  	if (n < 0 || n >= PATH_MAX) {
  		warn("snprintf");
  		goto err;
  	}
  	free(r);
  	return (s);
  
  err:
  	free(s);
  	free(r);
  	return (NULL);
  }
  
  /*
   * Adapted from Hacker's Delight crc32b().
   *
   * To quote http://www.hackersdelight.org/permissions.htm :
   *
   * "You are free to use, copy, and distribute any of the code on
   *  this web site, whether modified by you or not. You need not give
   *  attribution. This includes the algorithms (some of which appear
   *  in Hacker's Delight), the Hacker's Assistant, and any code submitted
   *  by readers. Submitters implicitly agree to this."
   */
  u_int32_t
  crc32(const u_char *buf, const u_int32_t size)
  {
  	int j;
  	u_int32_t i, byte, crc, mask;
  
  	crc = 0xFFFFFFFF;
  
  	for (i = 0; i < size; i++) {
  		byte = buf[i];			/* Get next byte. */
  		crc = crc ^ byte;
  		for (j = 7; j >= 0; j--) {	/* Do eight times. */
  			mask = -(crc & 1);
  			crc = (crc >> 1) ^ (0xEDB88320 & mask);
  		}
  	}
  
  	return ~crc;
  }