/* vi: set sw=4 ts=4: */ /* * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters * * Copyright 1999 George Staikos * * Licensed under GPLv2 or later, see file LICENSE in this source tree. * * Changelog: * v1.01 - added -p <preload> to preload values from a file * v1.01.1 - busybox applet aware by <solar@gentoo.org> */ //usage:#define sysctl_trivial_usage //usage: "[OPTIONS] [VALUE]..." //usage:#define sysctl_full_usage "\n\n" //usage: "Configure kernel parameters at runtime\n" //usage: "\n -n Don't print key names" //usage: "\n -e Don't warn about unknown keys" //usage: "\n -w Change sysctl setting" //usage: "\n -p FILE Load sysctl settings from FILE (default /etc/sysctl.conf)" //usage: "\n -a Display all values" //usage: "\n -A Display all values in table form" //usage: //usage:#define sysctl_example_usage //usage: "sysctl [-n] [-e] variable...\n" //usage: "sysctl [-n] [-e] -w variable=value...\n" //usage: "sysctl [-n] [-e] -a\n" //usage: "sysctl [-n] [-e] -p file (default /etc/sysctl.conf)\n" //usage: "sysctl [-n] [-e] -A\n" #include "libbb.h" enum { FLAG_SHOW_KEYS = 1 << 0, FLAG_SHOW_KEY_ERRORS = 1 << 1, FLAG_TABLE_FORMAT = 1 << 2, /* not implemented */ FLAG_SHOW_ALL = 1 << 3, FLAG_PRELOAD_FILE = 1 << 4, FLAG_WRITE = 1 << 5, }; #define OPTION_STR "neAapw" static void sysctl_dots_to_slashes(char *name) { char *cptr, *last_good, *end; /* Convert minimum number of '.' to '/' so that * we end up with existing file's name. * * Example from bug 3894: * net.ipv4.conf.eth0.100.mc_forwarding -> * net/ipv4/conf/eth0.100/mc_forwarding * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*, * therefore we must start from the end, and if * we replaced even one . -> /, start over again, * but never replace dots before the position * where last replacement occurred. * * Another bug we later had is that * net.ipv4.conf.eth0.100 * (without .mc_forwarding) was mishandled. * * To set up testing: modprobe 8021q; vconfig add eth0 100 */ end = name + strlen(name); last_good = name - 1; *end = '.'; /* trick the loop into trying full name too */ again: cptr = end; while (cptr > last_good) { if (*cptr == '.') { *cptr = '\0'; //bb_error_msg("trying:'%s'", name); if (access(name, F_OK) == 0) { *cptr = '/'; //bb_error_msg("replaced:'%s'", name); last_good = cptr; goto again; } *cptr = '.'; } cptr--; } *end = '\0'; } static int sysctl_act_on_setting(char *setting) { int fd, retval = EXIT_SUCCESS; char *cptr, *outname; char *value = value; /* for compiler */ outname = xstrdup(setting); cptr = outname; while (*cptr) { if (*cptr == '/') *cptr = '.'; cptr++; } if (option_mask32 & FLAG_WRITE) { cptr = strchr(setting, '='); if (cptr == NULL) { bb_error_msg("error: '%s' must be of the form name=value", outname); retval = EXIT_FAILURE; goto end; } value = cptr + 1; /* point to the value in name=value */ if (setting == cptr || !*value) { bb_error_msg("error: malformed setting '%s'", outname); retval = EXIT_FAILURE; goto end; } *cptr = '\0'; outname[cptr - setting] = '\0'; /* procps 3.2.7 actually uses these flags */ fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666); } else { fd = open(setting, O_RDONLY); } if (fd < 0) { switch (errno) { case ENOENT: if (option_mask32 & FLAG_SHOW_KEY_ERRORS) bb_error_msg("error: '%s' is an unknown key", outname); break; default: bb_perror_msg("error %sing key '%s'", option_mask32 & FLAG_WRITE ? "sett" : "read", outname); break; } retval = EXIT_FAILURE; goto end; } if (option_mask32 & FLAG_WRITE) { //TODO: procps 3.2.7 writes "value\n", note trailing "\n" xwrite_str(fd, value); close(fd); if (option_mask32 & FLAG_SHOW_KEYS) printf("%s = ", outname); puts(value); } else { char c; value = cptr = xmalloc_read(fd, NULL); close(fd); if (value == NULL) { bb_perror_msg("error reading key '%s'", outname); goto end; } /* dev.cdrom.info and sunrpc.transports, for example, * are multi-line. Try "sysctl sunrpc.transports" */ while ((c = *cptr) != '\0') { if (option_mask32 & FLAG_SHOW_KEYS) printf("%s = ", outname); while (1) { fputc(c, stdout); cptr++; if (c == '\n') break; c = *cptr; if (c == '\0') break; } } free(value); } end: free(outname); return retval; } static int sysctl_act_recursive(const char *path) { DIR *dirp; struct stat buf; struct dirent *entry; char *next; int retval = 0; stat(path, &buf); if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) { dirp = opendir(path); if (dirp == NULL) return -1; while ((entry = readdir(dirp)) != NULL) { next = concat_subpath_file(path, entry->d_name); if (next == NULL) continue; /* d_name is "." or ".." */ /* if path was ".", drop "./" prefix: */ retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ? next + 2 : next); free(next); } closedir(dirp); } else { char *name = xstrdup(path); retval |= sysctl_act_on_setting(name); free(name); } return retval; } /* Set sysctl's from a conf file. Format example: * # Controls IP packet forwarding * net.ipv4.ip_forward = 0 */ static int sysctl_handle_preload_file(const char *filename) { char *token[2]; parser_t *parser; parser = config_open(filename); /* Must do it _after_ config_open(): */ xchdir("/proc/sys"); /* xchroot("/proc/sys") - if you are paranoid */ //TODO: ';' is comment char too //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value // (but _whitespace_ from ends should be trimmed first (and we do it right)) //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1") // can it be fixed by removing PARSE_COLLAPSE bit? while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) { char *tp; sysctl_dots_to_slashes(token[0]); tp = xasprintf("%s=%s", token[0], token[1]); sysctl_act_recursive(tp); free(tp); } if (ENABLE_FEATURE_CLEAN_UP) config_close(parser); return 0; } int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int sysctl_main(int argc UNUSED_PARAM, char **argv) { int retval; int opt; opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */ argv += optind; opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS); option_mask32 = opt; if (opt & FLAG_PRELOAD_FILE) { option_mask32 |= FLAG_WRITE; /* xchdir("/proc/sys") is inside */ return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf"); } xchdir("/proc/sys"); /* xchroot("/proc/sys") - if you are paranoid */ if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) { return sysctl_act_recursive("."); } retval = 0; while (*argv) { sysctl_dots_to_slashes(*argv); retval |= sysctl_act_recursive(*argv); argv++; } return retval; }