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freebsd/usr.bin/kenv/kenv.c
Peter Wemm c87a63c10f Initial kenv(1) hack for dumping the kernel environment. This can be
used to extract modified boot hints to make loader(8)-time changes
"sticky".  It tries to use \ style quoting so that it can be used directly
with foo.conf files.  It can also extract specific variables.
2000-07-08 08:33:40 +00:00

132 lines
3.3 KiB
C

/*
* Copyright (c) 2000 Peter Wemm <peter@freebsd.org>
*
* 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 AUTHORS 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 AUTHORS 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/sysctl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <err.h>
#include <unistd.h>
static char sbuf[1024];
static void
usage(void)
{
errx(1, "usage: [-h] [variable]");
}
int
main(int argc, char **argv)
{
int name2oid_oid[2];
int real_oid[CTL_MAXNAME+4];
size_t oidlen;
int ch, error, hflag, i, slen;
char *env, *eq, *name, *var, *val;
hflag = 0;
env = NULL;
while ((ch = getopt(argc, argv, "h")) != -1) {
switch (ch) {
case 'h':
hflag++;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc > 0) {
env = argv[0];
argv++;
argc--;
}
if (argc > 0)
usage();
name2oid_oid[0] = 0; /* This is magic & undocumented! */
name2oid_oid[1] = 3;
oidlen = sizeof(real_oid);
name = "kern.environment";
error = sysctl(name2oid_oid, 2, real_oid, &oidlen, name, strlen(name));
if (error < 0)
err(1, "cannot find kern.environment base sysctl OID");
oidlen /= sizeof (int);
if (oidlen >= CTL_MAXNAME)
errx(1, "kern.environment OID is too large!");
real_oid[oidlen] = 0;
for (i = 0; ; i++) {
real_oid[oidlen + 1] = i;
slen = sizeof(sbuf) - 1;
error = sysctl(real_oid, oidlen + 2, sbuf, &slen, NULL, 0);
if (error < 0) {
if (errno != ENOENT)
err(1, "sysctl kern.environment.%d\n", i);
break;
}
sbuf[sizeof(sbuf) - 1] = '\0';
eq = strchr(sbuf, '=');
if (eq == NULL)
err(1, "malformed environment string: %s\n", sbuf);
var = sbuf;
*eq = '\0';
val = eq + 1;
if (env) {
if (strcmp(var, env) != 0)
continue;
printf("%s\n", val);
break;
}
if (hflag) {
if (strncmp(var, "hint.", 5) != 0)
continue;
/* FALLTHROUGH */
}
printf("%s=\"", var);
while (*val) {
switch (*val) {
case '"':
putchar('\\');
putchar('"');
break;
case '\\':
putchar('\\');
putchar('\\');
break;
default:
putchar(*val);
break;
}
val++;
}
printf("\"\n");
}
exit(0);
}