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procps/sysctl.c

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/*
* Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
*
* "Copyright 1999 George Staikos
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Changelog:
* v1.01:
* - added -p <preload> to preload values from a file
* Horms:
* - added -q to be quiet when modifying values
*
* Changes by Albert Cahalan, 2002.
*/
#include <dirent.h>
#include <errno.h>
#include <getopt.h>
#include <glob.h>
#include <libgen.h>
#include <limits.h>
#include <regex.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "c.h"
#include "fileutils.h"
#include "nls.h"
#include "xalloc.h"
/*
* Globals...
*/
static const char PROC_PATH[] = "/proc/sys/";
static const char DEFAULT_PRELOAD[] = "/etc/sysctl.conf";
static const char *DEPRECATED[] = {
"base_reachable_time",
"retrans_time",
""
};
static bool IgnoreDeprecated;
static bool NameOnly;
static bool PrintName;
static bool PrintNewline;
static bool IgnoreError;
static bool Quiet;
static char *pattern;
/* Function prototypes. */
static int pattern_match(const char *string, const char *pat);
static int DisplayAll(const char *restrict const path);
static void slashdot(char *restrict p, char old, char new)
{
int warned = 1;
p = strpbrk(p, "/.");
if (!p)
/* nothing -- can't be, but oh well */
return;
if (*p == new)
/* already in desired format */
return;
while (p) {
char c = *p;
if ((*(p + 1) == '/' || *(p + 1) == '.') && warned) {
xwarnx(_("separators should not be repeated: %s"), p);
warned = 0;
}
if (c == old)
*p = new;
if (c == new)
*p = old;
p = strpbrk(p + 1, "/.");
}
}
/*
* Display the usage format
*/
static void __attribute__ ((__noreturn__))
Usage(FILE * out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] [variable[=value] ...]\n"),
program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -a, --all display all variables\n"), out);
fputs(_(" -A alias of -a\n"), out);
fputs(_(" -X alias of -a\n"), out);
fputs(_(" --deprecated include deprecated parameters to listing\n"), out);
fputs(_(" -b, --binary print value without new line\n"), out);
fputs(_(" -e, --ignore ignore unknown variables errors\n"), out);
fputs(_(" -N, --names print variable names without values\n"), out);
fputs(_(" -n, --values print only values of a variables\n"), out);
fputs(_(" -p, --load[=<file>] read values from file\n"), out);
fputs(_(" -f alias of -p\n"), out);
fputs(_(" --system read values from all system directories\n"), out);
fputs(_(" -r, --pattern <expression>\n"
" select setting that match expression\n"), out);
fputs(_(" -q, --quiet do not echo variable set\n"), out);
fputs(_(" -w, --write enable writing a value to variable\n"), out);
fputs(_(" -o does nothing\n"), out);
fputs(_(" -x does nothing\n"), out);
fputs(_(" -d alias of -h\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("sysctl(8)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
/*
* Strip the leading and trailing spaces from a string
*/
static char *StripLeadingAndTrailingSpaces(char *oneline)
{
char *t;
if (!oneline || !*oneline)
return oneline;
t = oneline;
t += strlen(oneline) - 1;
while ((*t == ' ' || *t == '\t' || *t == '\n' || *t == '\r') && t != oneline)
*t-- = 0;
t = oneline;
while ((*t == ' ' || *t == '\t') && *t != 0)
t++;
return t;
}
/*
* Read a sysctl setting
*/
static int ReadSetting(const char *restrict const name)
{
int rc = 0;
char *restrict tmpname;
char *restrict outname;
char inbuf[1025];
FILE *restrict fp;
struct stat ts;
if (!name || !*name) {
xwarnx(_("\"%s\" is an unknown key"), name);
return -1;
}
/* used to display the output */
outname = xstrdup(name);
/* change / to . */
slashdot(outname, '/', '.');
/* used to open the file */
tmpname = xmalloc(strlen(name) + strlen(PROC_PATH) + 2);
strcpy(tmpname, PROC_PATH);
strcat(tmpname, name);
/* change . to / */
slashdot(tmpname + strlen(PROC_PATH), '.', '/');
/* used to display the output */
outname = xstrdup(name);
/* change / to . */
slashdot(outname, '/', '.');
if (stat(tmpname, &ts) < 0) {
if (!IgnoreError) {
xwarn(_("cannot stat %s"), tmpname);
rc = -1;
}
goto out;
}
if ((ts.st_mode & S_IRUSR) == 0)
goto out;
if (S_ISDIR(ts.st_mode)) {
size_t len;
len = strlen(tmpname);
tmpname[len] = '/';
tmpname[len + 1] = '\0';
rc = DisplayAll(tmpname);
goto out;
}
if (pattern && !pattern_match(outname, pattern)) {
free(outname);
return 0;
}
fp = fopen(tmpname, "r");
if (!fp) {
switch (errno) {
case ENOENT:
if (!IgnoreError) {
xwarnx(_("\"%s\" is an unknown key"), outname);
rc = -1;
}
break;
case EACCES:
xwarnx(_("permission denied on key '%s'"), outname);
rc = -1;
break;
default:
xwarn(_("reading key \"%s\""), outname);
rc = -1;
break;
}
} else {
errno = 0;
if (fgets(inbuf, sizeof inbuf - 1, fp)) {
/* this loop is required, see
* /sbin/sysctl -a | egrep -6 dev.cdrom.info
*/
do {
if (NameOnly) {
fprintf(stdout, "%s\n", outname);
} else {
/* already has the \n in it */
if (PrintName) {
fprintf(stdout, "%s = %s",
outname, inbuf);
if (inbuf[strlen(inbuf) - 1] != '\n')
putchar('\n');
} else {
if (!PrintNewline) {
char *nlptr =
strchr(inbuf, '\n');
if (nlptr)
*nlptr = '\0';
}
fprintf(stdout, "%s", inbuf);
}
}
} while (fgets(inbuf, sizeof inbuf - 1, fp));
} else {
switch (errno) {
case EACCES:
xwarnx(_("permission denied on key '%s'"),
outname);
rc = -1;
break;
case EISDIR: {
size_t len;
len = strlen(tmpname);
tmpname[len] = '/';
tmpname[len + 1] = '\0';
fclose(fp);
rc = DisplayAll(tmpname);
goto out;
}
default:
xwarnx(_("reading key \"%s\""), outname);
rc = -1;
case 0:
break;
}
}
fclose(fp);
}
out:
free(tmpname);
free(outname);
return rc;
}
static int is_deprecated(char *filename)
{
int i;
for (i = 0; strlen(DEPRECATED[i]); i++) {
if (strcmp(DEPRECATED[i], filename) == 0)
return 1;
}
return 0;
}
/*
* Display all the sysctl settings
*/
static int DisplayAll(const char *restrict const path)
{
int rc = 0;
int rc2;
DIR *restrict dp;
struct dirent *restrict de;
struct stat ts;
dp = opendir(path);
if (!dp) {
xwarnx(_("unable to open directory \"%s\""), path);
rc = -1;
} else {
readdir(dp); /* skip . */
readdir(dp); /* skip .. */
while ((de = readdir(dp))) {
char *restrict tmpdir;
if (IgnoreDeprecated && is_deprecated(de->d_name))
continue;
tmpdir =
(char *restrict) xmalloc(strlen(path) +
strlen(de->d_name) +
2);
sprintf(tmpdir, "%s%s", path, de->d_name);
rc2 = stat(tmpdir, &ts);
if (rc2 != 0) {
xwarn(_("cannot stat %s"), tmpdir);
} else {
if (S_ISDIR(ts.st_mode)) {
strcat(tmpdir, "/");
DisplayAll(tmpdir);
} else {
rc |=
ReadSetting(tmpdir +
strlen(PROC_PATH));
}
}
free(tmpdir);
}
closedir(dp);
}
return rc;
}
/*
* Write a sysctl setting
*/
static int WriteSetting(const char *setting)
{
int rc = 0;
const char *name = setting;
const char *value;
const char *equals;
char *tmpname;
char *outname;
char *last_dot;
FILE *fp;
struct stat ts;
if (!name)
/* probably don't want to display this err */
return 0;
equals = strchr(setting, '=');
if (!equals) {
xwarnx(_("\"%s\" must be of the form name=value"),
setting);
return -1;
}
/* point to the value in name=value */
value = equals + 1;
if (!*name || !*value || name == equals) {
xwarnx(_("malformed setting \"%s\""), setting);
return -2;
}
/* used to open the file */
tmpname = xmalloc(equals - name + 1 + strlen(PROC_PATH));
strcpy(tmpname, PROC_PATH);
strncat(tmpname, name, (int) (equals - name));
tmpname[equals - name + strlen(PROC_PATH)] = 0;
/* change . to / */
slashdot(tmpname + strlen(PROC_PATH), '.', '/');
/* used to display the output */
outname = xmalloc(equals - name + 1);
strncpy(outname, name, (int) (equals - name));
outname[equals - name] = 0;
/* change / to . */
slashdot(outname, '/', '.');
last_dot = strrchr(outname, '.');
if (last_dot != NULL && is_deprecated(last_dot + 1)) {
xwarnx(_("%s is deprecated, value not set"), outname);
goto out;
}
if (stat(tmpname, &ts) < 0) {
if (!IgnoreError) {
xwarn(_("cannot stat %s"), tmpname);
rc = -1;
}
goto out;
}
if ((ts.st_mode & S_IWUSR) == 0) {
xwarn(_("setting key \"%s\""), outname);
goto out;
}
if (S_ISDIR(ts.st_mode)) {
xwarn(_("setting key \"%s\""), outname);
goto out;
}
fp = fopen(tmpname, "w");
if (!fp) {
switch (errno) {
case ENOENT:
if (!IgnoreError) {
xwarnx(_("\"%s\" is an unknown key"), outname);
rc = -1;
}
break;
case EACCES:
xwarnx(_("permission denied on key '%s'"), outname);
rc = -1;
break;
default:
xwarn(_("setting key \"%s\""), outname);
rc = -1;
break;
}
} else {
rc = fprintf(fp, "%s\n", value);
if (0 < rc)
rc = 0;
if (close_stream(fp) != 0)
xwarn(_("setting key \"%s\""), outname);
if (rc == 0 && !Quiet) {
if (NameOnly) {
fprintf(stdout, "%s\n", outname);
} else {
if (PrintName) {
fprintf(stdout, "%s = %s\n",
outname, value);
} else {
if (PrintNewline)
fprintf(stdout, "%s\n", value);
else
fprintf(stdout, "%s", value);
}
}
}
}
out:
free(tmpname);
free(outname);
return rc;
}
static int pattern_match(const char *string, const char *pat)
{
int status;
regex_t re;
if (regcomp(&re, pat, REG_EXTENDED | REG_NOSUB) != 0)
return (0);
status = regexec(&re, string, (size_t) 0, NULL, 0);
regfree(&re);
if (status != 0)
return (0);
return (1);
}
#define LINELEN 4096
/*
* Preload the sysctl's from the conf file. We parse the file and then
* reform it (strip out whitespace).
*/
static int Preload(const char *restrict const filename)
{
char oneline[LINELEN];
char buffer[LINELEN];
FILE *fp;
char *t;
int n = 0;
int rc = 0;
char *name, *value;
glob_t globbuf;
int globerr;
int globflg;
int j;
globflg = GLOB_NOCHECK;
#ifdef GLOB_BRACE
globflg |= GLOB_BRACE;
#endif
#ifdef GLOB_TILDE
globflg |= GLOB_TILDE;
#else
if (filename[0] == '~')
xwarnx(_("GLOB_TILDE is not supported on your platform, "
"the tilde in \"%s\" won't be expanded."), filename);
#endif
globerr = glob(filename, globflg, NULL, &globbuf);
if (globerr != 0 && globerr != GLOB_NOMATCH)
xerr(EXIT_FAILURE, _("glob failed"));
for (j = 0; j < globbuf.gl_pathc; j++) {
fp = (globbuf.gl_pathv[j][0] == '-' && !globbuf.gl_pathv[j][1])
? stdin : fopen(globbuf.gl_pathv[j], "r");
if (!fp) {
xwarn(_("cannot open \"%s\""), globbuf.gl_pathv[j]);
return -1;
}
while (fgets(oneline, sizeof oneline, fp)) {
n++;
t = StripLeadingAndTrailingSpaces(oneline);
if (strlen(t) < 2)
continue;
if (*t == '#' || *t == ';')
continue;
name = strtok(t, "=");
if (!name || !*name) {
xwarnx(_("%s(%d): invalid syntax, continuing..."),
globbuf.gl_pathv[j], n);
continue;
}
StripLeadingAndTrailingSpaces(name);
if (pattern && !pattern_match(name, pattern))
continue;
value = strtok(NULL, "\n\r");
if (!value || !*value) {
xwarnx(_("%s(%d): invalid syntax, continuing..."),
globbuf.gl_pathv[j], n);
continue;
}
while ((*value == ' ' || *value == '\t') && *value != 0)
value++;
/* should NameOnly affect this? */
sprintf(buffer, "%s=%s", name, value);
rc |= WriteSetting(buffer);
}
fclose(fp);
}
return rc;
}
struct pair {
char *name;
char *value;
};
static int sortpairs(const void *A, const void *B)
{
const struct pair *a = *(struct pair * const *) A;
const struct pair *b = *(struct pair * const *) B;
return strcmp(a->name, b->name);
}
static int PreloadSystem(void)
{
unsigned di, i;
const char *dirs[] = {
"/run/sysctl.d",
"/etc/sysctl.d",
"/usr/local/lib/sysctl.d",
"/usr/lib/sysctl.d",
"/lib/sysctl.d",
};
struct pair **cfgs = NULL;
unsigned ncfgs = 0;
int rc = 0;
struct stat ts;
enum { nprealloc = 16 };
for (di = 0; di < sizeof(dirs) / sizeof(dirs[0]); ++di) {
struct dirent *de;
DIR *dp = opendir(dirs[di]);
if (!dp)
continue;
while ((de = readdir(dp))) {
if (!strcmp(de->d_name, ".")
|| !strcmp(de->d_name, ".."))
continue;
if (strlen(de->d_name) < 5
|| strcmp(de->d_name + strlen(de->d_name) - 5, ".conf"))
continue;
/* check if config already known */
for (i = 0; i < ncfgs; ++i) {
if (cfgs && !strcmp(cfgs[i]->name, de->d_name))
break;
}
if (i < ncfgs)
/* already in */
continue;
if (ncfgs % nprealloc == 0)
cfgs =
xrealloc(cfgs,
sizeof(struct pair *) * (ncfgs +
nprealloc));
if (cfgs) {
cfgs[ncfgs] =
xmalloc(sizeof(struct pair) +
strlen(de->d_name) * 2 + 2 +
strlen(dirs[di]) + 1);
cfgs[ncfgs]->name =
(char *)cfgs[ncfgs] + sizeof(struct pair);
strcpy(cfgs[ncfgs]->name, de->d_name);
cfgs[ncfgs]->value =
(char *)cfgs[ncfgs] + sizeof(struct pair) +
strlen(cfgs[ncfgs]->name) + 1;
sprintf(cfgs[ncfgs]->value, "%s/%s", dirs[di],
de->d_name);
ncfgs++;
} else {
xerrx(EXIT_FAILURE, _("internal error"));
}
}
closedir(dp);
}
qsort(cfgs, ncfgs, sizeof(struct cfg *), sortpairs);
for (i = 0; i < ncfgs; ++i) {
if (!Quiet)
printf(_("* Applying %s ...\n"), cfgs[i]->value);
rc |= Preload(cfgs[i]->value);
}
if (stat(DEFAULT_PRELOAD, &ts) == 0 && S_ISREG(ts.st_mode)) {
if (!Quiet)
printf(_("* Applying %s ...\n"), DEFAULT_PRELOAD);
rc |= Preload(DEFAULT_PRELOAD);
}
/* cleaning */
for (i = 0; i < ncfgs; ++i) {
free(cfgs[i]);
}
if (cfgs) free(cfgs);
return rc;
}
/*
* Main...
*/
int main(int argc, char *argv[])
{
bool WriteMode = false;
bool DisplayAllOpt = false;
bool preloadfileOpt = false;
int ReturnCode = 0;
int c;
const char *preloadfile = NULL;
enum {
DEPRECATED_OPTION = CHAR_MAX + 1,
SYSTEM_OPTION
};
static const struct option longopts[] = {
{"all", no_argument, NULL, 'a'},
{"deprecated", no_argument, NULL, DEPRECATED_OPTION},
{"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'},
{"system", no_argument, NULL, SYSTEM_OPTION},
{"pattern", required_argument, NULL, 'r'},
{"help", no_argument, NULL, 'h'},
{"version", no_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
};
#ifdef HAVE_PROGRAM_INVOCATION_NAME
program_invocation_name = program_invocation_short_name;
#endif
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
PrintName = true;
PrintNewline = true;
IgnoreError = false;
Quiet = false;
IgnoreDeprecated = true;
if (argc < 2)
Usage(stderr);
while ((c =
getopt_long(argc, argv, "bneNwfp::qoxaAXr:Vdh", longopts,
NULL)) != -1) {
switch (c) {
case 'b':
/* This is "binary" format, which means more for BSD. */
PrintNewline = false;
/* FALL THROUGH */
case 'n':
PrintName = false;
break;
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.
*/
IgnoreError = true;
break;
case 'N':
NameOnly = true;
break;
case 'w':
WriteMode = true;
break;
case 'f': /* the NetBSD way */
case 'p':
preloadfileOpt = true;
if (optarg)
preloadfile = optarg;
break;
case 'q':
Quiet = true;
break;
case 'o': /* BSD: binary values too, 1st 16 bytes in hex */
case 'x': /* BSD: binary values too, whole thing in hex */
/* does nothing */ ;
break;
case 'a': /* string and integer values (for Linux, all of them) */
case 'A': /* same as -a -o */
case 'X': /* same as -a -x */
DisplayAllOpt = true;
break;
case DEPRECATED_OPTION:
IgnoreDeprecated = false;
break;
case SYSTEM_OPTION:
IgnoreError = true;
return PreloadSystem();
case 'r':
pattern = xstrdup(optarg);
break;
case 'V':
printf(PROCPS_NG_VERSION);
return EXIT_SUCCESS;
case 'd': /* BSD: print description ("vm.kvm_size: Size of KVM") */
case 'h': /* BSD: human-readable (did FreeBSD 5 make -e default?) */
case '?':
Usage(stdout);
default:
Usage(stderr);
}
}
argc -= optind;
argv += optind;
if (DisplayAllOpt)
return DisplayAll(PROC_PATH);
if (preloadfileOpt) {
int ret = EXIT_SUCCESS, i;
if (!preloadfile) {
if (!argc) {
ret |= Preload(DEFAULT_PRELOAD);
}
} else {
/* This happens when -pfile option is
* used without space. */
ret |= Preload(preloadfile);
}
for (i = 0; i < argc; i++)
ret |= Preload(argv[i]);
return ret;
}
if (argc < 1)
xerrx(EXIT_FAILURE, _("no variables specified\n"
"Try `%s --help' for more information."),
program_invocation_short_name);
if (NameOnly && Quiet)
xerrx(EXIT_FAILURE, _("options -N and -q cannot coexist\n"
"Try `%s --help' for more information."),
program_invocation_short_name);
for ( ; *argv; argv++) {
if (WriteMode || index(*argv, '='))
ReturnCode += WriteSetting(*argv);
else
ReturnCode += ReadSetting(*argv);
}
return ReturnCode;
}
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