1 /* sysctl.c - A utility to read and manipulate the sysctl parameters.
3 * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
4 * Copyright 2014 Kyungwan Han <asura321@gmail.com>
8 USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_SBIN))
14 usage: sysctl [-aAeNnqw] [-p [FILE] | KEY[=VALUE]...]
16 Read/write system control data (under /proc/sys).
19 -e Don't warn about unknown keys
20 -N Don't print key values
21 -n Don't print key names
22 -p [FILE] Read values from FILE (default /etc/sysctl.conf)
23 -q Don't show value after write
24 -w Only write values (object to reading)
29 // Null terminate at =, return value
30 static char *split_key(char *key)
32 char *value = strchr(key, '=');
34 if (value) *(value++)=0;
39 static void replace_char(char *str, char old, char new)
41 for (; *str; str++) if (*str == old) *str = new;
44 static void key_error(char *key)
46 if (errno == ENOENT) {
47 if (!(toys.optflags & FLAG_e)) error_msg("unknown key '%s'", key);
48 } else perror_msg("key '%s'", key);
51 static int write_key(char *path, char *key, char *value)
53 int fd = open(path, O_WRONLY);;
60 xwrite(fd, value, strlen(value));
66 // Display all keys under a path
67 static int do_show_keys(struct dirtree *dt)
69 char *path, *data, *key;
71 if (!dirtree_notdotdot(dt)) return 0; // Skip . and ..
72 if (S_ISDIR(dt->st.st_mode)) return DIRTREE_RECURSE;
74 path = dirtree_path(dt, 0);
75 data = readfile(path, 0, 0);
76 replace_char(key = path + 10, '/', '.'); // skip "/proc/sys/"
77 if (!data) key_error(key);
79 // Print the parts that aren't switched off by flags.
80 if (!(toys.optflags & FLAG_n)) xprintf("%s", key);
81 if (!(toys.optflags & (FLAG_N|FLAG_n))) xprintf(" = ");
82 for (key = data+strlen(data); key > data && isspace(*--key); *key = 0);
83 if (!(toys.optflags & FLAG_N)) xprintf("%s", data);
84 if ((toys.optflags & (FLAG_N|FLAG_n)) != (FLAG_N|FLAG_n)) xputc('\n');
93 // Read/write entries under a key. Accepts "key=value" in key if !value
94 static void process_key(char *key, char *value)
98 if (!value) value = split_key(key);
99 if ((toys.optflags & FLAG_w) && !value) {
100 error_msg("'%s' not key=value", key);
105 path = xmprintf("/proc/sys/%s", key);
106 replace_char(path, '.', '/');
107 // Note: failure to assign to a non-leaf node suppresses the display.
108 if (!(value && (!write_key(path, key, value) || (toys.optflags & FLAG_q)))) {
109 if (!access(path, R_OK)) dirtree_read(path, do_show_keys);
120 if (toys.optflags & FLAG_a) dirtree_read("/proc/sys", do_show_keys);
123 else if (toys.optflags & FLAG_p) {
124 FILE *fp = xfopen(*toys.optargs ? *toys.optargs : "/etc/sysctl.conf", "r");
128 char *line = 0, *key, *val;
130 if (-1 == (len = getline(&line, &len, fp))) break;
132 while (isspace(*key)) key++;
133 if (*key == '#' || *key == ';' || !*key) continue;
134 while (len && isspace(line[len-1])) line[--len] = 0;
135 if (!(val = split_key(line))) {
136 error_msg("'%s' not key=value", line);
140 // Trim whitespace around =
142 while (len && isspace(line[len-1])) line[--len] = 0;
143 while (isspace(*val)) val++;;
145 process_key(key, val);
150 // Loop through arguments, displaying or assigning as appropriate
151 } else for (args = toys.optargs; *args; args++) process_key(*args, 0);