freebsd-dev/usr.bin/perror/perror.c
George V. Neville-Neil 9a3009b800 Add a new program, perror, which takes an errno as a command line argument
and outputs the associated textual message in the same way that
perror(3) would if called within a program.
2009-05-19 17:40:22 +00:00

77 lines
2.2 KiB
C

/*-
* Copyright (c) 2009 Advanced Computing Technologies LLC
* Written by: George V. Neville-Neil <gnn@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/errno.h>
#define MAX_ERR 256
void usage()
{
printf("usage: perror number\n");
printf("number must be between 1 and %d\n", ELAST);
exit(1);
}
int main(int argc, char **argv)
{
char errstr[MAX_ERR];
char *cp;
int errnum;
if (argc != 2)
usage();
errnum = strtol(argv[1], &cp, 0);
if (((errnum == 0) && (errno == EINVAL)) || (*cp != '\0')) {
printf("Argument %s not a number.\n", argv[1]);
usage();
}
if ((errnum <=0) || (errnum > ELAST)) {
printf("Number %d out of range.\n", errnum);
usage();
}
if (strerror_r(errnum, errstr, sizeof(errstr)) < 0) {
printf("Could not find error number %d.\n", errnum);
usage();
}
printf("Error %d is \"%s\"\n", errnum, errstr);
exit(0);
}