diff options
Diffstat (limited to 'procps/sysctl.c')
| -rw-r--r-- | procps/sysctl.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/procps/sysctl.c b/procps/sysctl.c new file mode 100644 index 0000000..860c840 --- /dev/null +++ b/procps/sysctl.c @@ -0,0 +1,268 @@ +/* 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 tarball for details. + * + * Changelog: + * v1.01: + * - added -p <preload> to preload values from a file + * v1.01.1 + * - busybox applet aware by <solar@gentoo.org> + * + */ + +#include "libbb.h" + +static int sysctl_read_setting(const char *setting); +static int sysctl_write_setting(const char *setting); +static int sysctl_display_all(const char *path); +static int sysctl_preload_file_and_exit(const char *filename); +static void sysctl_dots_to_slashes(char *name); + +static const char ETC_SYSCTL_CONF[] ALIGN1 = "/etc/sysctl.conf"; +static const char PROC_SYS[] ALIGN1 = "/proc/sys/"; +enum { strlen_PROC_SYS = sizeof(PROC_SYS) - 1 }; + +static const char msg_unknown_key[] ALIGN1 = + "error: '%s' is an unknown key"; + +static void dwrite_str(int fd, const char *buf) +{ + write(fd, buf, strlen(buf)); +} + +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, +}; + +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, "+neAapw"); /* '+' - stop on first non-option */ + argv += optind; + opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS); + option_mask32 ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS); + + if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) + return sysctl_display_all(PROC_SYS); + if (opt & FLAG_PRELOAD_FILE) + return sysctl_preload_file_and_exit(*argv ? *argv : ETC_SYSCTL_CONF); + + retval = 0; + while (*argv) { + if (opt & FLAG_WRITE) + retval |= sysctl_write_setting(*argv); + else + retval |= sysctl_read_setting(*argv); + argv++; + } + + return retval; +} /* end sysctl_main() */ + +/* Set sysctl's from a conf file. Format example: + * # Controls IP packet forwarding + * net.ipv4.ip_forward = 0 + */ +static int sysctl_preload_file_and_exit(const char *filename) +{ + char *token[2]; + parser_t *parser; + + parser = config_open(filename); +// TODO: ';' is comment char too + while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) { +#if 0 + char *s = xasprintf("%s=%s", token[0], token[1]); + sysctl_write_setting(s); + free(s); +#else /* Save ~4 bytes by using parser internals */ + sprintf(parser->line, "%s=%s", token[0], token[1]); // must have room by definition + sysctl_write_setting(parser->line); +#endif + } + if (ENABLE_FEATURE_CLEAN_UP) + config_close(parser); + return 0; +} /* end sysctl_preload_file_and_exit() */ + +static int sysctl_write_setting(const char *setting) +{ + int retval; + const char *name; + const char *value; + const char *equals; + char *tmpname, *outname, *cptr; + int fd; + + name = setting; + equals = strchr(setting, '='); + if (!equals) { + bb_error_msg("error: '%s' must be of the form name=value", setting); + return EXIT_FAILURE; + } + + value = equals + 1; /* point to the value in name=value */ + if (name == equals || !*value) { + bb_error_msg("error: malformed setting '%s'", setting); + return EXIT_FAILURE; + } + + tmpname = xasprintf("%s%.*s", PROC_SYS, (int)(equals - name), name); + outname = xstrdup(tmpname + strlen_PROC_SYS); + + sysctl_dots_to_slashes(tmpname); + + while ((cptr = strchr(outname, '/')) != NULL) + *cptr = '.'; + + fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666); + if (fd < 0) { + switch (errno) { + case ENOENT: + if (option_mask32 & FLAG_SHOW_KEY_ERRORS) + bb_error_msg(msg_unknown_key, outname); + break; + default: + bb_perror_msg("error setting key '%s'", outname); + break; + } + retval = EXIT_FAILURE; + } else { + dwrite_str(fd, value); + close(fd); + if (option_mask32 & FLAG_SHOW_KEYS) { + printf("%s = ", outname); + } + puts(value); + retval = EXIT_SUCCESS; + } + + free(tmpname); + free(outname); + return retval; +} /* end sysctl_write_setting() */ + +static int sysctl_read_setting(const char *name) +{ + int retval; + char *tmpname, *outname, *cptr; + char inbuf[1025]; + FILE *fp; + + if (!*name) { + if (option_mask32 & FLAG_SHOW_KEY_ERRORS) + bb_error_msg(msg_unknown_key, name); + return -1; + } + + tmpname = concat_path_file(PROC_SYS, name); + outname = xstrdup(tmpname + strlen_PROC_SYS); + + sysctl_dots_to_slashes(tmpname); + + while ((cptr = strchr(outname, '/')) != NULL) + *cptr = '.'; + + fp = fopen_for_read(tmpname); + if (fp == NULL) { + switch (errno) { + case ENOENT: + if (option_mask32 & FLAG_SHOW_KEY_ERRORS) + bb_error_msg(msg_unknown_key, outname); + break; + default: + bb_perror_msg("error reading key '%s'", outname); + break; + } + retval = EXIT_FAILURE; + } else { + while (fgets(inbuf, sizeof(inbuf) - 1, fp)) { + if (option_mask32 & FLAG_SHOW_KEYS) { + printf("%s = ", outname); + } + fputs(inbuf, stdout); + } + fclose(fp); + retval = EXIT_SUCCESS; + } + + free(tmpname); + free(outname); + return retval; +} /* end sysctl_read_setting() */ + +static int sysctl_display_all(const char *path) +{ + int retval = EXIT_SUCCESS; + DIR *dp; + struct dirent *de; + char *tmpdir; + struct stat ts; + + dp = opendir(path); + if (!dp) { + return EXIT_FAILURE; + } + while ((de = readdir(dp)) != NULL) { + tmpdir = concat_subpath_file(path, de->d_name); + if (tmpdir == NULL) + continue; /* . or .. */ + if (stat(tmpdir, &ts) != 0) { + bb_perror_msg(tmpdir); + } else if (S_ISDIR(ts.st_mode)) { + retval |= sysctl_display_all(tmpdir); + } else { + retval |= sysctl_read_setting(tmpdir + strlen_PROC_SYS); + } + free(tmpdir); + } /* end while */ + closedir(dp); + + return retval; +} /* end sysctl_display_all() */ + +static void sysctl_dots_to_slashes(char *name) +{ + char *cptr, *last_good, *end; + + /* It can be good as-is! */ + if (access(name, F_OK) == 0) + return; + + /* 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 replacement occurred. */ + end = name + strlen(name) - 1; + last_good = name - 1; + again: + cptr = end; + while (cptr > last_good) { + if (*cptr == '.') { + *cptr = '\0'; + if (access(name, F_OK) == 0) { + *cptr = '/'; + last_good = cptr; + goto again; + } + *cptr = '.'; + } + cptr--; + } +} /* end sysctl_dots_to_slashes() */ |