src/shared/sysctl-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8
   9 #include "fd-util.h"
  10 #include "fileio.h"
  11 #include "log.h"
  12 #include "macro.h"
  13 #include "string-util.h"
  14 #include "sysctl-util.h"
  15
  16 char *sysctl_normalize(char *s) {
  17         char *n;
  18
  19         n = strpbrk(s, "/.");
  20         /* If the first separator is a slash, the path is
  21          * assumed to be normalized and slashes remain slashes
  22          * and dots remains dots. */
  23         if (!n || *n == '/')
  24                 return s;
  25
  26         /* Otherwise, dots become slashes and slashes become
  27          * dots. Fun. */
  28         while (n) {
  29                 if (*n == '.')
  30                         *n = '/';
  31                 else
  32                         *n = '.';
  33
  34                 n = strpbrk(n + 1, "/.");
  35         }
  36
  37         return s;
  38 }
  39
  40 int sysctl_write(const char *property, const char *value) {
  41         char *p;
  42         _cleanup_close_ int fd = -1;
  43
  44         assert(property);
  45         assert(value);
  46
  47         log_debug("Setting '%s' to '%s'", property, value);
  48
  49         p = strjoina("/proc/sys/", property);
  50         fd = open(p, O_WRONLY|O_CLOEXEC);
  51         if (fd < 0)
  52                 return -errno;
  53
  54         if (!endswith(value, "\n"))
  55                 value = strjoina(value, "\n");
  56
  57         if (write(fd, value, strlen(value)) < 0)
  58                 return -errno;
  59
  60         return 0;
  61 }
  62
  63 int sysctl_read(const char *property, char **content) {
  64         char *p;
  65
  66         assert(property);
  67         assert(content);
  68
  69         p = strjoina("/proc/sys/", property);
  70         return read_full_file(p, content, NULL);
  71 }