1 /* sysctl.c - A utility to read and manipulate the sysctl parameters.
14     usage: sysctl [-aAeNnqw] [-p [FILE] | KEY[=VALUE]...]
18     -a,A	Show all values
19     -e	Don't warn about unknown keys
20     -N	Don't print key values
21     -n	Don't print key names
22     -p	Read values from FILE (default /etc/sysctl.conf)
23     -q	Don't show value after write
24     -w	Only write values (object to reading)
30 static char *split_key(char *key)  in split_key()  argument
32   char *value = strchr(key, '=');  in split_key()
44 static void key_error(char *key)  in key_error()  argument
47     if (!(toys.optflags & FLAG_e)) error_msg("unknown key '%s'", key);  in key_error()
48   } else perror_msg("key '%s'", key);  in key_error()
51 static int write_key(char *path, char *key, char *value)  in write_key()  argument
53   int fd = open(path, O_WRONLY);  in write_key()
56     key_error(key);  in write_key()
66 // Display all keys under a path
69   char *path, *data, *key;  in do_show_keys()  local
72   if (S_ISDIR(dt->st.st_mode)) return DIRTREE_RECURSE;  in do_show_keys()
74   path = dirtree_path(dt, 0);  in do_show_keys()
75   data = readfile(path, 0, 0);  in do_show_keys()
76   replace_char(key = path + 10, '/', '.'); // skip "/proc/sys/"  in do_show_keys()
77   if (!data) key_error(key);  in do_show_keys()
80     if (!(toys.optflags & FLAG_n)) xprintf("%s", key);  in do_show_keys()
82     for (key = data+strlen(data); key > data && isspace(*--key); *key = 0);  in do_show_keys()
88   free(path);  in do_show_keys()
93 // Read/write entries under a key. Accepts "key=value" in key if !value
94 static void process_key(char *key, char *value)  in process_key()  argument
96   char *path;  in process_key()  local
98   if (!value) value = split_key(key);  in process_key()
100     error_msg("'%s' not key=value", key);  in process_key()
105   path = xmprintf("/proc/sys/%s", key);  in process_key()
106   replace_char(path, '.', '/');  in process_key()
107   // Note: failure to assign to a non-leaf node suppresses the display.  in process_key()
108   if (!(value && (!write_key(path, key, value) || (toys.optflags & FLAG_q)))) {  in process_key()
109     if (!access(path, R_OK)) dirtree_read(path, do_show_keys);  in process_key()
110     else key_error(key);  in process_key()
112   free(path);  in process_key()
128       char *line = 0, *key, *val;  in sysctl_main()  local
130       if (-1 == (len = getline(&line, &len, fp))) break;  in sysctl_main()
131       key = line;  in sysctl_main()
132       while (isspace(*key)) key++;  in sysctl_main()
133       if (*key == '#' || *key == ';' || !*key) continue;  in sysctl_main()
134       while (len && isspace(line[len-1])) line[--len] = 0;  in sysctl_main()
136         error_msg("'%s' not key=value", line);  in sysctl_main()
141       len = (val-line)-1;  in sysctl_main()
142       while (len && isspace(line[len-1])) line[--len] = 0;  in sysctl_main()
145       process_key(key, val);  in sysctl_main()