/* sysctl.c - A utility to read and manipulate the sysctl parameters. * * Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com> * Copyright 2014 Kyungwan Han <asura321@gmail.com> * * No Standard USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_SBIN)) config SYSCTL bool "sysctl" default y help usage: sysctl [-aAeNnqw] [-p [FILE] | KEY[=VALUE]...] Read/write system control data (under /proc/sys). -a,A Show all values -e Don't warn about unknown keys -N Don't print key values -n Don't print key names -p Read values from FILE (default /etc/sysctl.conf) -q Don't show value after write -w Only write values (object to reading) */ #define FOR_sysctl #include "toys.h" // Null terminate at =, return value static char *split_key(char *key) { char *value = strchr(key, '='); if (value) *(value++)=0; return value; } static void replace_char(char *str, char old, char new) { for (; *str; str++) if (*str == old) *str = new; } static void key_error(char *key) { if (errno == ENOENT) { if (!(toys.optflags & FLAG_e)) error_msg("unknown key '%s'", key); } else perror_msg("key '%s'", key); } static int write_key(char *path, char *key, char *value) { int fd = open(path, O_WRONLY);; if (fd < 0) { key_error(key); return 0; } xwrite(fd, value, strlen(value)); xclose(fd); return 1; } // Display all keys under a path static int do_show_keys(struct dirtree *dt) { char *path, *data, *key; if (!dirtree_notdotdot(dt)) return 0; // Skip . and .. if (S_ISDIR(dt->st.st_mode)) return DIRTREE_RECURSE; path = dirtree_path(dt, 0); data = readfile(path, 0, 0); replace_char(key = path + 10, '/', '.'); // skip "/proc/sys/" if (!data) key_error(key); else { // Print the parts that aren't switched off by flags. if (!(toys.optflags & FLAG_n)) xprintf("%s", key); if (!(toys.optflags & (FLAG_N|FLAG_n))) xprintf(" = "); for (key = data+strlen(data); key > data && isspace(*--key); *key = 0); if (!(toys.optflags & FLAG_N)) xprintf("%s", data); if ((toys.optflags & (FLAG_N|FLAG_n)) != (FLAG_N|FLAG_n)) xputc('\n'); } free(data); free(path); return 0; } // Read/write entries under a key. Accepts "key=value" in key if !value static void process_key(char *key, char *value) { char *path; if (!value) value = split_key(key); if ((toys.optflags & FLAG_w) && !value) { error_msg("'%s' not key=value", key); return; } path = xmprintf("/proc/sys/%s", key); replace_char(path, '.', '/'); // Note: failure to assign to a non-leaf node suppresses the display. if (!(value && (!write_key(path, key, value) || (toys.optflags & FLAG_q)))) { if (!access(path, R_OK)) dirtree_read(path, do_show_keys); else key_error(key); } free(path); } void sysctl_main() { char **args = 0; // Display all keys if (toys.optflags & FLAG_a) dirtree_read("/proc/sys", do_show_keys); // read file else if (toys.optflags & FLAG_p) { FILE *fp = xfopen(*toys.optargs ? *toys.optargs : "/etc/sysctl.conf", "r"); size_t len; for (;;) { char *line = 0, *key, *val; if (-1 == (len = getline(&line, &len, fp))) break; key = line; while (isspace(*key)) key++; if (*key == '#' || *key == ';' || !*key) continue; while (len && isspace(line[len-1])) line[--len] = 0; if (!(val = split_key(line))) { error_msg("'%s' not key=value", line); continue; } // Trim whitespace around = len = (val-line)-1; while (len && isspace(line[len-1])) line[--len] = 0; while (isspace(*val)) val++;; process_key(key, val); free(line); } fclose(fp); // Loop through arguments, displaying or assigning as appropriate } else { if (!*toys.optargs) help_exit(0); for (args = toys.optargs; *args; args++) process_key(*args, 0); } }