sysctl: options handling & usage output
The sysctl now uses getopt_long and has help screen which be user friendly. Rest of the modernization is left later, since this is a command is used in scripts, and changing for instance error printing to use warn & warnx could break stuff. Signed-off-by: Sami Kerola <kerolasa@iki.fi>
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Sami Kerola
parent
d50884788d
commit
81df8e2630
219
sysctl.c
219
sysctl.c
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@ -22,20 +22,21 @@
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*/
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#include <dirent.h>
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#include <errno.h>
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#include <getopt.h>
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#include <libgen.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <dirent.h>
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#include <string.h>
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#include <errno.h>
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#include <libgen.h>
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#include <unistd.h>
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#include "proc/procps.h"
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#include "proc/version.h"
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// Proof that C++ causes brain damage:
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/* Proof that C++ causes brain damage: */
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typedef int bool;
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static bool true = 1;
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static bool false = 0;
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@ -53,7 +54,6 @@ static bool IgnoreError;
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static bool Quiet;
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/* error messages */
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static const char ERR_UNKNOWN_PARAMETER[] = "error: Unknown parameter \"%s\"\n";
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static const char ERR_MALFORMED_SETTING[] = "error: Malformed setting \"%s\"\n";
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static const char ERR_NO_EQUALS[] = "error: \"%s\" must be of the form name=value\n";
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static const char ERR_INVALID_KEY[] = "error: \"%s\" is an unknown key\n";
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@ -83,15 +83,33 @@ static void slashdot(char *restrict p, char old, char new){
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* Display the usage format
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*
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*/
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static int Usage(const char *restrict const name) {
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printf("usage: %s [-n] [-e] variable ... \n"
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" %s [-n] [-e] [-q] -w variable=value ... \n"
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" %s [-n] [-e] -a \n"
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" %s [-n] [-e] [-q] -p <file> (default /etc/sysctl.conf) \n"
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" %s [-n] [-e] -A\n", name, name, name, name, name);
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return -1;
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}
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static void __attribute__ ((__noreturn__))
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Usage(FILE * out)
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{
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fprintf(out,
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"\nUsage: %s [options] [variable[=value] ...]\n"
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"\nOptions:\n", program_invocation_short_name);
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fprintf(out,
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" -a, --all display all variables\n"
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" -A alias of -a\n"
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" -X alias of -a\n"
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" -b, --binary print value without new line\n"
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" -e, --ignore ignore unknown variables errors\n"
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" -N, --names print variable names without values\n"
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" -n, --values print only values of a variables\n"
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" -p, --load[=<file>] read values from file\n"
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" -f alias of -p\n"
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" -q, --quiet do not echo variable set\n"
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" -w, --write enable writing a value to variable\n"
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" -o does nothing\n"
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" -x does nothing\n"
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" -h, --help display this help text\n"
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" -d alias of -h\n"
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" -V, --version display version information and exit\n");
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fprintf(out, "\nFor more information see sysctl(8).\n");
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exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
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}
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/*
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* Strip the leading and trailing spaces from a string
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@ -460,106 +478,113 @@ static int Preload(const char *restrict const filename) {
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* Main...
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*
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*/
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int main(int argc, char *argv[]) {
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const char *me = (const char *)basename(argv[0]);
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int main(int argc, char *argv[])
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{
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bool SwitchesAllowed = true;
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bool WriteMode = false;
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bool DisplayAllOpt = false;
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bool preloadfileOpt = false;
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int ReturnCode = 0;
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int c;
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const char *preloadfile = DEFAULT_PRELOAD;
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static const struct option longopts[] = {
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{"all", no_argument, NULL, 'a'},
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{"binary", no_argument, NULL, 'b'},
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{"ignore", no_argument, NULL, 'e'},
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{"names", no_argument, NULL, 'N'},
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{"values", no_argument, NULL, 'n'},
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{"load", optional_argument, NULL, 'p'},
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{"quiet", no_argument, NULL, 'q'},
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{"write", no_argument, NULL, 'w'},
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{"help", no_argument, NULL, 'h'},
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{"version", no_argument, NULL, 'V'},
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{NULL, 0, NULL, 0}
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};
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PrintName = true;
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PrintNewline = true;
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IgnoreError = false;
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Quiet = false;
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if (argc < 2) {
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return Usage(me);
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Usage(stderr);
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}
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argv++;
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for (; argv && *argv && **argv; argv++) {
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if (SwitchesAllowed && **argv == '-') { /* we have a switch */
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if ((*argv)[1] && (*argv)[2]){ // don't yet handle "sysctl -ew"
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if (!strcmp("--help",*argv)) {
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Usage(me);
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exit(0);
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}
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if (!strcmp("--version",*argv)) {
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fprintf(stdout, "sysctl (%s)\n",procps_version);
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exit(0);
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}
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fprintf(stderr, ERR_UNKNOWN_PARAMETER, *argv);
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return Usage(me);
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}
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switch((*argv)[1]) {
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case 'b':
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/* This is "binary" format, which means more for BSD. */
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PrintNewline = false;
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/* FALL THROUGH */
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case 'n':
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PrintName = false;
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while ((c =
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getopt_long(argc, argv, "bneNwfpqoxaAXVdh", longopts,
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NULL)) != -1)
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switch (c) {
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case 'b':
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/* This is "binary" format, which means more for BSD. */
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PrintNewline = false;
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/* FALL THROUGH */
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case 'n':
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PrintName = false;
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break;
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case 'e':
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/*
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* For FreeBSD, -e means a "%s=%s\n" format. ("%s: %s\n" default)
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* We (and NetBSD) use "%s = %s\n" always, and -e to ignore errors.
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*/
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IgnoreError = true;
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break;
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case 'N':
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NameOnly = true;
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break;
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case 'w':
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SwitchesAllowed = false;
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WriteMode = true;
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break;
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case 'f': /* the NetBSD way */
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case 'p':
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preloadfileOpt = true;
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if (optarg)
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preloadfile = optarg;
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break;
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case 'e':
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// For FreeBSD, -e means a "%s=%s\n" format. ("%s: %s\n" default)
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// We (and NetBSD) use "%s = %s\n" always, and -e to ignore errors.
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IgnoreError = true;
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case 'q':
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Quiet = true;
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break;
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case 'o': /* BSD: binary values too, 1st 16 bytes in hex */
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case 'x': /* BSD: binary values too, whole thing in hex */
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/* does nothing */ ;
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break;
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case 'a': /* string and integer values (for Linux, all of them) */
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case 'A': /* same as -a -o */
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case 'X': /* same as -a -x */
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DisplayAllOpt = true;
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break;
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case 'N':
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NameOnly = true;
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break;
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case 'w':
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SwitchesAllowed = false;
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WriteMode = true;
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break;
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case 'f': // the NetBSD way
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case 'p':
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argv++;
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if (argv && *argv && **argv) {
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preloadfile = *argv;
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}
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return Preload(preloadfile);
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case 'q':
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Quiet = true;
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break;
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case 'o': // BSD: binary values too, 1st 16 bytes in hex
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case 'x': // BSD: binary values too, whole thing in hex
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/* does nothing */ ;
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break;
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case 'a': // string and integer values (for Linux, all of them)
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case 'A': // same as -a -o
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case 'X': // same as -a -x
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DisplayAllOpt = true;
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break;
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case 'V':
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fprintf(stdout, "sysctl (%s)\n",procps_version);
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exit(0);
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case 'd': // BSD: print description ("vm.kvm_size: Size of KVM")
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case 'h': // BSD: human-readable (did FreeBSD 5 make -e default?)
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case '?':
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return Usage(me);
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default:
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fprintf(stderr, ERR_UNKNOWN_PARAMETER, *argv);
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return Usage(me);
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}
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} else {
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if (NameOnly && Quiet) // nonsense
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return Usage(me);
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if (DisplayAllOpt) // We cannot have values with -a
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return Usage(me);
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SwitchesAllowed = false;
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if (WriteMode || strchr(*argv, '='))
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ReturnCode = WriteSetting(*argv);
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else
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ReturnCode = ReadSetting(*argv);
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case 'V':
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fprintf(stdout, "sysctl (%s)\n",procps_version);
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exit(0);
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case 'd': /* BSD: print description ("vm.kvm_size: Size of KVM") */
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case 'h': /* BSD: human-readable (did FreeBSD 5 make -e default?) */
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case '?':
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Usage(stdout);
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default:
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Usage(stderr);
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}
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}
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if (DisplayAllOpt) {
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if (Quiet)
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return Usage(me);
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if (DisplayAllOpt)
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return DisplayAll(PROC_PATH);
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}
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if (preloadfileOpt)
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return Preload(preloadfile);
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argc -= optind;
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argv += optind;
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if (argc < 1) {
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warnx("no variables specified");
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Usage(stderr);
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}
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if (NameOnly && Quiet) {
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warnx("options -N and -q can not coexist");
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Usage(stderr);
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}
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if (WriteMode || index(*argv, '='))
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ReturnCode = WriteSetting(*argv);
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else
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ReturnCode = ReadSetting(*argv);
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return ReturnCode;
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}
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