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sysctl: options handling & usage output

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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>
This commit is contained in:
Sami Kerola 2011-06-05 19:46:49 +02:00
parent d50884788d
commit 81df8e2630
1 changed files with 122 additions and 97 deletions
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159
sysctl.c
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@ -22,20 +22,21 @@
*/ */
#include <dirent.h>
#include <errno.h>
#include <getopt.h>
#include <libgen.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <unistd.h> #include <string.h>
#include <sys/stat.h> #include <sys/stat.h>
#include <sys/types.h> #include <sys/types.h>
#include <dirent.h> #include <unistd.h>
#include <string.h>
#include <errno.h>
#include <libgen.h>
#include "proc/procps.h" #include "proc/procps.h"
#include "proc/version.h" #include "proc/version.h"
// Proof that C++ causes brain damage: /* Proof that C++ causes brain damage: */
typedef int bool; typedef int bool;
static bool true = 1; static bool true = 1;
static bool false = 0; static bool false = 0;
@ -53,7 +54,6 @@ static bool IgnoreError;
static bool Quiet; static bool Quiet;
/* error messages */ /* error messages */
static const char ERR_UNKNOWN_PARAMETER[] = "error: Unknown parameter \"%s\"\n";
static const char ERR_MALFORMED_SETTING[] = "error: Malformed setting \"%s\"\n"; static const char ERR_MALFORMED_SETTING[] = "error: Malformed setting \"%s\"\n";
static const char ERR_NO_EQUALS[] = "error: \"%s\" must be of the form name=value\n"; static const char ERR_NO_EQUALS[] = "error: \"%s\" must be of the form name=value\n";
static const char ERR_INVALID_KEY[] = "error: \"%s\" is an unknown key\n"; static const char ERR_INVALID_KEY[] = "error: \"%s\" is an unknown key\n";
@ -83,15 +83,33 @@ static void slashdot(char *restrict p, char old, char new){
* Display the usage format * Display the usage format
* *
*/ */
static int Usage(const char *restrict const name) { static void __attribute__ ((__noreturn__))
printf("usage: %s [-n] [-e] variable ... \n" Usage(FILE * out)
" %s [-n] [-e] [-q] -w variable=value ... \n" {
" %s [-n] [-e] -a \n" fprintf(out,
" %s [-n] [-e] [-q] -p <file> (default /etc/sysctl.conf) \n" "\nUsage: %s [options] [variable[=value] ...]\n"
" %s [-n] [-e] -A\n", name, name, name, name, name); "\nOptions:\n", program_invocation_short_name);
return -1; fprintf(out,
} " -a, --all display all variables\n"
" -A alias of -a\n"
" -X alias of -a\n"
" -b, --binary print value without new line\n"
" -e, --ignore ignore unknown variables errors\n"
" -N, --names print variable names without values\n"
" -n, --values print only values of a variables\n"
" -p, --load[=<file>] read values from file\n"
" -f alias of -p\n"
" -q, --quiet do not echo variable set\n"
" -w, --write enable writing a value to variable\n"
" -o does nothing\n"
" -x does nothing\n"
" -h, --help display this help text\n"
" -d alias of -h\n"
" -V, --version display version information and exit\n");
fprintf(out, "\nFor more information see sysctl(8).\n");
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
/* /*
* Strip the leading and trailing spaces from a string * Strip the leading and trailing spaces from a string
@ -460,40 +478,43 @@ static int Preload(const char *restrict const filename) {
* Main... * Main...
* *
*/ */
int main(int argc, char *argv[]) { int main(int argc, char *argv[])
const char *me = (const char *)basename(argv[0]); {
bool SwitchesAllowed = true; bool SwitchesAllowed = true;
bool WriteMode = false; bool WriteMode = false;
bool DisplayAllOpt = false; bool DisplayAllOpt = false;
bool preloadfileOpt = false;
int ReturnCode = 0; int ReturnCode = 0;
int c;
const char *preloadfile = DEFAULT_PRELOAD; const char *preloadfile = DEFAULT_PRELOAD;
static const struct option longopts[] = {
{"all", no_argument, NULL, 'a'},
{"binary", no_argument, NULL, 'b'},
{"ignore", no_argument, NULL, 'e'},
{"names", no_argument, NULL, 'N'},
{"values", no_argument, NULL, 'n'},
{"load", optional_argument, NULL, 'p'},
{"quiet", no_argument, NULL, 'q'},
{"write", no_argument, NULL, 'w'},
{"help", no_argument, NULL, 'h'},
{"version", no_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
};
PrintName = true; PrintName = true;
PrintNewline = true; PrintNewline = true;
IgnoreError = false; IgnoreError = false;
Quiet = false; Quiet = false;
if (argc < 2) { if (argc < 2) {
return Usage(me); Usage(stderr);
} }
argv++; while ((c =
getopt_long(argc, argv, "bneNwfpqoxaAXVdh", longopts,
for (; argv && *argv && **argv; argv++) { NULL)) != -1)
if (SwitchesAllowed && **argv == '-') { /* we have a switch */ switch (c) {
if ((*argv)[1] && (*argv)[2]){ // don't yet handle "sysctl -ew"
if (!strcmp("--help",*argv)) {
Usage(me);
exit(0);
}
if (!strcmp("--version",*argv)) {
fprintf(stdout, "sysctl (%s)\n",procps_version);
exit(0);
}
fprintf(stderr, ERR_UNKNOWN_PARAMETER, *argv);
return Usage(me);
}
switch((*argv)[1]) {
case 'b': case 'b':
/* This is "binary" format, which means more for BSD. */ /* This is "binary" format, which means more for BSD. */
PrintNewline = false; PrintNewline = false;
@ -502,8 +523,10 @@ int main(int argc, char *argv[]) {
PrintName = false; PrintName = false;
break; break;
case 'e': case 'e':
// For FreeBSD, -e means a "%s=%s\n" format. ("%s: %s\n" default) /*
// We (and NetBSD) use "%s = %s\n" always, and -e to ignore errors. * For FreeBSD, -e means a "%s=%s\n" format. ("%s: %s\n" default)
* We (and NetBSD) use "%s = %s\n" always, and -e to ignore errors.
*/
IgnoreError = true; IgnoreError = true;
break; break;
case 'N': case 'N':
@ -513,53 +536,55 @@ int main(int argc, char *argv[]) {
SwitchesAllowed = false; SwitchesAllowed = false;
WriteMode = true; WriteMode = true;
break; break;
case 'f': // the NetBSD way case 'f': /* the NetBSD way */
case 'p': case 'p':
argv++; preloadfileOpt = true;
if (argv && *argv && **argv) { if (optarg)
preloadfile = *argv; preloadfile = optarg;
} break;
return Preload(preloadfile);
case 'q': case 'q':
Quiet = true; Quiet = true;
break; break;
case 'o': // BSD: binary values too, 1st 16 bytes in hex case 'o': /* BSD: binary values too, 1st 16 bytes in hex */
case 'x': // BSD: binary values too, whole thing in hex case 'x': /* BSD: binary values too, whole thing in hex */
/* does nothing */ ; /* does nothing */ ;
break; break;
case 'a': // string and integer values (for Linux, all of them) case 'a': /* string and integer values (for Linux, all of them) */
case 'A': // same as -a -o case 'A': /* same as -a -o */
case 'X': // same as -a -x case 'X': /* same as -a -x */
DisplayAllOpt = true; DisplayAllOpt = true;
break; break;
case 'V': case 'V':
fprintf(stdout, "sysctl (%s)\n",procps_version); fprintf(stdout, "sysctl (%s)\n",procps_version);
exit(0); exit(0);
case 'd': // BSD: print description ("vm.kvm_size: Size of KVM") case 'd': /* BSD: print description ("vm.kvm_size: Size of KVM") */
case 'h': // BSD: human-readable (did FreeBSD 5 make -e default?) case 'h': /* BSD: human-readable (did FreeBSD 5 make -e default?) */
case '?': case '?':
return Usage(me); Usage(stdout);
default: default:
fprintf(stderr, ERR_UNKNOWN_PARAMETER, *argv); Usage(stderr);
return Usage(me);
} }
} else { if (DisplayAllOpt)
if (NameOnly && Quiet) // nonsense return DisplayAll(PROC_PATH);
return Usage(me); if (preloadfileOpt)
if (DisplayAllOpt) // We cannot have values with -a return Preload(preloadfile);
return Usage(me);
SwitchesAllowed = false; argc -= optind;
if (WriteMode || strchr(*argv, '=')) argv += optind;
if (argc < 1) {
warnx("no variables specified");
Usage(stderr);
}
if (NameOnly && Quiet) {
warnx("options -N and -q can not coexist");
Usage(stderr);
}
if (WriteMode || index(*argv, '='))
ReturnCode = WriteSetting(*argv); ReturnCode = WriteSetting(*argv);
else else
ReturnCode = ReadSetting(*argv); ReturnCode = ReadSetting(*argv);
}
}
if (DisplayAllOpt) {
if (Quiet)
return Usage(me);
return DisplayAll(PROC_PATH);
}
return ReturnCode; return ReturnCode;
} }