busybox/procps/sysctl.c

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/* vi: set sw=4 ts=4: */
/*
* Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
*
* Copyright 1999 George Staikos
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* Changelog:
* v1.01:
* - added -p <preload> to preload values from a file
* v1.01.1
* - busybox applet aware by <solar@gentoo.org>
*
*/
#include "libbb.h"
/*
* Function Prototypes
*/
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_PRELOAD_FILE[] =
"error: cannot open preload file '%s'\n";
static const char WARN_BAD_LINE[] =
"warning: %s(%d): invalid syntax, continuing...\n";
static void dwrite_str(int fd, const char *buf)
{
write(fd, buf, strlen(buf));
}
/*
* sysctl_main()...
*/
int sysctl_main(int argc, char **argv);
int sysctl_main(int argc, char **argv)
{
int retval = 0;
int output = 1;
int write_mode = 0;
int switches_allowed = 1;
if (argc < 2)
bb_show_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 '?':
bb_show_usage();
default:
bb_error_msg(ERR_UNKNOWN_PARAMETER, *argv);
bb_show_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() */
/*
* sysctl_preload_file
* preload the sysctl's from a conf file
* - we parse the file and then reform it (strip out whitespace)
*/
#define PRELOAD_BUF 256
int sysctl_preload_file(const char *filename, int output)
{
int lineno = 0;
char oneline[PRELOAD_BUF];
char buffer[PRELOAD_BUF];
char *name, *value, *ptr;
FILE *fp = NULL;
if (!filename || ((fp = fopen(filename, "r")) == NULL)) {
bb_error_msg_and_die(ERR_PRELOAD_FILE, filename);
}
while (fgets(oneline, sizeof(oneline) - 1, fp)) {
oneline[sizeof(oneline) - 1] = '\0';
lineno++;
trim(oneline);
ptr = (char *) oneline;
if (*ptr == '#' || *ptr == ';')
continue;
if (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++;
/* safe because sizeof(oneline) == sizeof(buffer) */
sprintf(buffer, "%s=%s", name, value);
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 = strchr(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 = xasprintf("%s%.*s", PROC_PATH, (int)(equals - name), name);
outname = xstrdup(tmpname + strlen(PROC_PATH));
while ((cptr = strchr(tmpname, '.')) != NULL)
*cptr = '/';
while ((cptr = strchr(outname, '/')) != NULL)
*cptr = '.';
fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
if (fd < 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 {
dwrite_str(fd, value);
close(fd);
if (output) {
dwrite_str(STDOUT_FILENO, outname);
dwrite_str(STDOUT_FILENO, " = ");
}
dwrite_str(STDOUT_FILENO, value);
dwrite_str(STDOUT_FILENO, "\n");
}
/* 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 = concat_path_file(PROC_PATH, name);
outname = xstrdup(tmpname + strlen(PROC_PATH));
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) {
dwrite_str(STDOUT_FILENO, outname);
dwrite_str(STDOUT_FILENO, " = ");
}
dwrite_str(STDOUT_FILENO, 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;
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dp = opendir(path);
if (!dp) {
retval = -1;
} else {
while ((de = readdir(dp)) != NULL) {
tmpdir = concat_subpath_file(path, de->d_name);
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if (tmpdir == NULL)
continue;
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retval2 = stat(tmpdir, &ts);
if (retval2 != 0)
bb_perror_msg(tmpdir);
else {
if (S_ISDIR(ts.st_mode)) {
sysctl_display_all(tmpdir, output, show_table);
} else
retval |=
sysctl_read_setting(tmpdir + strlen(PROC_PATH),
output);
}
free(tmpdir);
} /* end while */
closedir(dp);
}
return retval;
} /* end sysctl_display_all() */