busybox/procps/sysctl.c

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/*
* Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
*
*
* "Copyright 1999 George Staikos
* This file may be used subject to the terms and conditions of the
* GNU General Public License Version 2, or any later version
* at your option, as published by the Free Software Foundation.
* 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."
*
* Changelog:
* v1.01:
* - added -p <preload> to preload values from a file
* v1.01.1
* - busybox applet aware by <solar@gentoo.org>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include "busybox.h"
/*
* Function Prototypes
*/
static int sysctl_usage(void);
static int sysctl_read_setting(const char *setting, int output);
static int sysctl_write_setting(const char *setting, int output);
static int sysctl_preload_file(const char *filename, int output);
static int sysctl_display_all(const char *path, int output, int show_table);
/*
* Globals...
*/
static const char *PROC_PATH = "/proc/sys/";
static const char *DEFAULT_PRELOAD = "/etc/sysctl.conf";
/* 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_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_UNKNOWN_WRITING =
"error: unknown error %d setting key '%s'\n";
static const char *ERR_UNKNOWN_READING =
"error: unknown error %d reading key '%s'\n";
static const char *ERR_PERMISSION_DENIED =
"error: permission denied on key '%s'\n";
static const char *ERR_OPENING_DIR = "error: unable to open directory '%s'\n";
static const char *ERR_PRELOAD_FILE =
"error: unable to open preload file '%s'\n";
static const char *WARN_BAD_LINE =
"warning: %s(%d): invalid syntax, continuing...\n";
/*
* sysctl_main()...
*/
int sysctl_main(int argc, char **argv)
{
int retval = 0;
int output = 1;
int write_mode = 0;
int switches_allowed = 1;
if (argc < 2)
return sysctl_usage();
argv++;
for (; argv && *argv && **argv; argv++) {
if (switches_allowed && **argv == '-') { /* we have a switch */
switch ((*argv)[1]) {
case 'n':
output = 0;
break;
case 'w':
write_mode = 1;
switches_allowed = 0;
break;
case 'p':
argv++;
return
sysctl_preload_file(((argv && *argv
&& **argv) ? *argv :
DEFAULT_PRELOAD), output);
case 'a':
case 'A':
switches_allowed = 0;
return sysctl_display_all(PROC_PATH, output,
((*argv)[1] == 'a') ? 0 : 1);
case 'h':
case '?':
return sysctl_usage();
default:
bb_error_msg(ERR_UNKNOWN_PARAMETER, *argv);
return sysctl_usage();
}
} else {
switches_allowed = 0;
if (write_mode)
retval = sysctl_write_setting(*argv, output);
else
sysctl_read_setting(*argv, output);
}
}
return retval;
} /* end sysctl_main() */
/*
* Display the sysctl_usage format
*/
int sysctl_usage()
{
bb_show_usage();
return -1;
} /* end sysctl_usage() */
/*
* sysctl_preload_file
* preload the sysctl's from a conf file
* - we parse the file and then reform it (strip out whitespace)
*/
int sysctl_preload_file(const char *filename, int output)
{
int lineno = 0;
char oneline[256];
char buffer[256];
char *name, *value, *ptr;
FILE *fp = NULL;
if (!filename || ((fp = fopen(filename, "r")) == NULL)) {
bb_error_msg(ERR_PRELOAD_FILE, filename);
return 1;
}
while (fgets(oneline, sizeof(oneline) - 1, fp)) {
oneline[sizeof(oneline) - 1] = 0;
lineno++;
trim(oneline);
ptr = (char *) oneline;
if (*ptr == '#' || *ptr == ';')
continue;
if (bb_strlen(ptr) < 2)
continue;
name = strtok(ptr, "=");
if (!name || !*name) {
bb_error_msg(WARN_BAD_LINE, filename, lineno);
continue;
}
trim(name);
value = strtok(NULL, "\n\r");
if (!value || !*value) {
bb_error_msg(WARN_BAD_LINE, filename, lineno);
continue;
}
while ((*value == ' ' || *value == '\t') && *value != 0)
value++;
strncpy(buffer, name, sizeof(buffer));
strncat(buffer, "=", sizeof(buffer));
strncat(buffer, value, sizeof(buffer));
sysctl_write_setting(buffer, output);
}
fclose(fp);
return 0;
} /* end sysctl_preload_file() */
/*
* Write a single sysctl setting
*/
int sysctl_write_setting(const char *setting, int output)
{
int retval = 0;
const char *name = setting;
const char *value;
const char *equals;
char *tmpname, *outname, *cptr;
int fd = -1;
if (!name) /* probably dont' want to display this err */
return 0;
if (!(equals = index(setting, '='))) {
bb_error_msg(ERR_NO_EQUALS, setting);
return -1;
}
value = equals + sizeof(char); /* point to the value in name=value */
if (!*name || !*value || name == equals) {
bb_error_msg(ERR_MALFORMED_SETTING, setting);
return -2;
}
tmpname =
(char *) xmalloc((equals - name + 1 + bb_strlen(PROC_PATH)) *
sizeof(char));
outname = (char *) xmalloc((equals - name + 1) * sizeof(char));
strcpy(tmpname, PROC_PATH);
strncat(tmpname, name, (int) (equals - name));
tmpname[equals - name + bb_strlen(PROC_PATH)] = 0;
strncpy(outname, name, (int) (equals - name));
outname[equals - name] = 0;
while ((cptr = strchr(tmpname, '.')) != NULL)
*cptr = '/';
while ((cptr = strchr(outname, '/')) != NULL)
*cptr = '.';
if ((fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) {
switch (errno) {
case ENOENT:
bb_error_msg(ERR_INVALID_KEY, outname);
break;
case EACCES:
bb_perror_msg(ERR_PERMISSION_DENIED, outname);
break;
default:
bb_error_msg(ERR_UNKNOWN_WRITING, errno, outname);
break;
}
retval = -1;
} else {
write(fd, value, bb_strlen(value));
close(fd);
if (output) {
write(STDOUT_FILENO, outname, bb_strlen(outname));
write(STDOUT_FILENO, " = ", 3);
}
write(STDOUT_FILENO, value, bb_strlen(value));
write(STDOUT_FILENO, "\n", 1);
}
/* cleanup */
free(tmpname);
free(outname);
return retval;
} /* end sysctl_write_setting() */
/*
* Read a sysctl setting
*
*/
int sysctl_read_setting(const char *setting, int output)
{
int retval = 0;
char *tmpname, *outname, *cptr;
char inbuf[1025];
const char *name = setting;
FILE *fp;
if (!setting || !*setting)
bb_error_msg(ERR_INVALID_KEY, setting);
tmpname =
(char *) xmalloc((bb_strlen(name) + bb_strlen(PROC_PATH) + 1) *
sizeof(char));
outname = (char *) xmalloc((bb_strlen(name) + 1) * sizeof(char));
strcpy(tmpname, PROC_PATH);
strcat(tmpname, name);
strcpy(outname, name);
while ((cptr = strchr(tmpname, '.')) != NULL)
*cptr = '/';
while ((cptr = strchr(outname, '/')) != NULL)
*cptr = '.';
if ((fp = fopen(tmpname, "r")) == NULL) {
switch (errno) {
case ENOENT:
bb_error_msg(ERR_INVALID_KEY, outname);
break;
case EACCES:
bb_error_msg(ERR_PERMISSION_DENIED, outname);
break;
default:
bb_error_msg(ERR_UNKNOWN_READING, errno, outname);
break;
}
retval = -1;
} else {
while (fgets(inbuf, sizeof(inbuf) - 1, fp)) {
if (output) {
write(STDOUT_FILENO, outname, bb_strlen(outname));
write(STDOUT_FILENO, " = ", 3);
}
write(STDOUT_FILENO, inbuf, bb_strlen(inbuf));
}
fclose(fp);
}
free(tmpname);
free(outname);
return retval;
} /* end sysctl_read_setting() */
/*
* Display all the sysctl settings
*
*/
int sysctl_display_all(const char *path, int output, int show_table)
{
int retval = 0;
int retval2;
DIR *dp;
struct dirent *de;
char *tmpdir;
struct stat ts;
if (!(dp = opendir(path))) {
bb_perror_msg(ERR_OPENING_DIR, path);
retval = -1;
} else {
readdir(dp);
readdir(dp); /* skip . and .. */
while ((de = readdir(dp)) != NULL) {
tmpdir =
(char *) xmalloc(bb_strlen(path) + bb_strlen(de->d_name) + 2);
strcpy(tmpdir, path);
strcat(tmpdir, de->d_name);
if ((retval2 = stat(tmpdir, &ts)) != 0)
bb_perror_msg(tmpdir);
else {
if (S_ISDIR(ts.st_mode)) {
strcat(tmpdir, "/");
sysctl_display_all(tmpdir, output, show_table);
} else
retval |=
sysctl_read_setting(tmpdir + bb_strlen(PROC_PATH),
output);
}
free(tmpdir);
} /* end while */
closedir(dp);
}
return retval;
} /* end sysctl_display_all() */
#ifdef STANDALONE_SYSCTL
int main(int argc, char **argv)
{
return sysctl_main(argc, argv);
}
#endif