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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include "af-list.h"
#include "fd-util.h"
#include "fileio.h"
#include "log.h"
#include "macro.h"
#include "path-util.h"
#include "socket-util.h"
#include "string-util.h"
#include "sysctl-util.h"
char *sysctl_normalize(char *s) {
char *n;
n = strpbrk(s, "/.");
/* If the first separator is a slash, the path is
* assumed to be normalized and slashes remain slashes
* and dots remains dots. */
if (n && *n == '.')
/* Dots become slashes and slashes become dots. Fun. */
do {
if (*n == '.')
*n = '/';
else
*n = '.';
n = strpbrk(n + 1, "/.");
} while (n);
path_simplify(s);
/* Kill the leading slash, but keep the first character of the string in the same place. */
if (s[0] == '/' && s[1] != 0)
memmove(s, s+1, strlen(s));
return s;
}
int sysctl_write(const char *property, const char *value) {
char *p;
assert(property);
assert(value);
p = strjoina("/proc/sys/", property);
path_simplify(p);
if (!path_is_normalized(p))
return -EINVAL;
log_debug("Setting '%s' to '%s'", p, value);
return write_string_file(p, value, WRITE_STRING_FILE_VERIFY_ON_FAILURE | WRITE_STRING_FILE_DISABLE_BUFFER | WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL);
}
int sysctl_writef(const char *property, const char *format, ...) {
_cleanup_free_ char *v = NULL;
va_list ap;
int r;
va_start(ap, format);
r = vasprintf(&v, format, ap);
va_end(ap);
if (r < 0)
return -ENOMEM;
return sysctl_write(property, v);
}
int sysctl_write_ip_property(int af, const char *ifname, const char *property, const char *value) {
const char *p;
assert(property);
assert(value);
if (!IN_SET(af, AF_INET, AF_INET6))
return -EAFNOSUPPORT;
if (ifname) {
if (!ifname_valid_full(ifname, IFNAME_VALID_SPECIAL))
return -EINVAL;
p = strjoina("net/", af_to_ipv4_ipv6(af), "/conf/", ifname, "/", property);
} else
p = strjoina("net/", af_to_ipv4_ipv6(af), "/", property);
return sysctl_write(p, value);
}
int sysctl_read(const char *property, char **ret) {
char *p;
int r;
assert(property);
p = strjoina("/proc/sys/", property);
path_simplify(p);
if (!path_is_normalized(p)) /* Filter out attempts to write to /proc/sys/../../…, just in case */
return -EINVAL;
r = read_full_virtual_file(p, ret, NULL);
if (r < 0)
return r;
if (ret)
delete_trailing_chars(*ret, NEWLINE);
return r;
}
int sysctl_read_ip_property(int af, const char *ifname, const char *property, char **ret) {
const char *p;
assert(property);
if (!IN_SET(af, AF_INET, AF_INET6))
return -EAFNOSUPPORT;
if (ifname) {
if (!ifname_valid_full(ifname, IFNAME_VALID_SPECIAL))
return -EINVAL;
p = strjoina("net/", af_to_ipv4_ipv6(af), "/conf/", ifname, "/", property);
} else
p = strjoina("net/", af_to_ipv4_ipv6(af), "/", property);
return sysctl_read(p, ret);
}
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