1 /* vi: set sw=4 ts=4: */
5 * Copyright (C) tons of folks. Tracking down who wrote what
6 * isn't something I'm going to worry about... If you wrote something
7 * here, please feel free to acknowledge your work.
9 * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
10 * Permission has been granted to redistribute this code under the GPL.
12 * Licensed under GPLv2 or later, see file License in this tarball for details.
18 /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
19 #if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
20 #warning Static linking against glibc produces buggy executables
21 #warning (glibc does not cope well with ld --gc-sections).
22 #warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
23 #warning Note that glibc is unsuitable for static linking anyway.
24 #warning If you still want to do it, remove -Wl,--gc-sections
25 #warning from top-level Makefile and remove this warning.
29 /* Declare <applet>_main() */
34 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
35 /* Define usage_messages[] */
36 static const char usage_messages[] = ""
43 #define usage_messages 0
44 #endif /* SHOW_USAGE */
46 /* Define struct bb_applet applets[] */
48 /* The -1 arises because of the {0,NULL,0,-1} entry. */
49 const unsigned short NUM_APPLETS = sizeof(applets) / sizeof(applets[0]) - 1;
52 const struct bb_applet *current_applet;
53 const char *applet_name ATTRIBUTE_EXTERNALLY_VISIBLE;
60 #if ENABLE_FEATURE_SUID_CONFIG
62 /* applets[] is const, so we have to define this "override" structure */
63 static struct BB_suid_config {
64 const struct bb_applet *m_applet;
68 struct BB_suid_config *m_next;
71 static bool suid_cfg_readable;
73 /* check if u is member of group g */
74 static int ingroup(uid_t u, gid_t g)
76 struct group *grp = getgrgid(g);
81 for (mem = grp->gr_mem; *mem; mem++) {
82 struct passwd *pwd = getpwnam(*mem);
84 if (pwd && (pwd->pw_uid == u))
91 /* This should probably be a libbb routine. In that case,
92 * I'd probably rename it to something like bb_trimmed_slice.
94 static char *get_trimmed_slice(char *s, char *e)
96 /* First, consider the value at e to be nul and back up until we
97 * reach a non-space char. Set the char after that (possibly at
98 * the original e) to nul. */
106 /* Next, advance past all leading space and return a ptr to the
107 * first non-space char; possibly the terminating nul. */
108 return skip_whitespace(s);
111 /* Don't depend on the tools to combine strings. */
112 static const char config_file[] = "/etc/busybox.conf";
114 /* There are 4 chars + 1 nul for each of user/group/other. */
115 static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
117 /* We don't supply a value for the nul, so an index adjustment is
118 * necessary below. Also, we use unsigned short here to save some
119 * space even though these are really mode_t values. */
120 static const unsigned short mode_mask[] = {
121 /* SST sst xxx --- */
122 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
123 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
124 0, S_IXOTH, S_IXOTH, 0 /* other */
127 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
129 static void parse_config_file(void)
131 struct BB_suid_config *sct_head;
132 struct BB_suid_config *sct;
133 const struct bb_applet *applet;
144 assert(!suid_config); /* Should be set to NULL by bss init. */
146 if ((stat(config_file, &st) != 0) /* No config file? */
147 || !S_ISREG(st.st_mode) /* Not a regular file? */
148 || (st.st_uid != 0) /* Not owned by root? */
149 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
150 || !(f = fopen(config_file, "r")) /* Cannot open? */
155 suid_cfg_readable = 1;
162 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
163 if (ferror(f)) { /* Make sure it wasn't a read error. */
164 parse_error("reading");
167 suid_config = sct_head; /* Success, so set the pointer. */
171 lc++; /* Got a (partial) line. */
173 /* If a line is too long for our buffer, we consider it an error.
174 * The following test does mistreat one corner case though.
175 * If the final line of the file does not end with a newline and
176 * yet exactly fills the buffer, it will be treated as too long
177 * even though there isn't really a problem. But it isn't really
178 * worth adding code to deal with such an unlikely situation, and
179 * we do err on the side of caution. Besides, the line would be
180 * too long if it did end with a newline. */
181 if (!strchr(s, '\n') && !feof(f)) {
182 parse_error("line too long");
185 /* Trim leading and trailing whitespace, ignoring comments, and
186 * check if the resulting string is empty. */
187 s = get_trimmed_slice(s, strchrnul(s, '#'));
192 /* Check for a section header. */
195 /* Unlike the old code, we ignore leading and trailing
196 * whitespace for the section name. We also require that
197 * there are no stray characters after the closing bracket. */
199 if (!e /* Missing right bracket? */
200 || e[1] /* Trailing characters? */
201 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
203 parse_error("section header");
205 /* Right now we only have one section so just check it.
206 * If more sections are added in the future, please don't
207 * resort to cascading ifs with multiple strcasecmp calls.
208 * That kind of bloated code is all too common. A loop
209 * and a string table would be a better choice unless the
210 * number of sections is very small. */
211 if (strcasecmp(s, "SUID") == 0) {
215 section = -1; /* Unknown section so set to skip. */
219 /* Process sections. */
221 if (section == 1) { /* SUID */
222 /* Since we trimmed leading and trailing space above, we're
223 * now looking for strings of the form
224 * <key>[::space::]*=[::space::]*<value>
225 * where both key and value could contain inner whitespace. */
227 /* First get the key (an applet name in our case). */
230 s = get_trimmed_slice(s, e);
232 if (!e || !*s) { /* Missing '=' or empty key. */
233 parse_error("keyword");
236 /* Ok, we have an applet name. Process the rhs if this
237 * applet is currently built in and ignore it otherwise.
238 * Note: this can hide config file bugs which only pop
239 * up when the busybox configuration is changed. */
240 applet = find_applet_by_name(s);
242 /* Note: We currently don't check for duplicates!
243 * The last config line for each applet will be the
244 * one used since we insert at the head of the list.
245 * I suppose this could be considered a feature. */
246 sct = xmalloc(sizeof(struct BB_suid_config));
247 sct->m_applet = applet;
249 sct->m_next = sct_head;
252 /* Get the specified mode. */
254 e = skip_whitespace(e+1);
256 for (i = 0; i < 3; i++) {
258 q = strchrnul(mode_chars + 5*i, *e++);
262 /* Adjust by -i to account for nul. */
263 sct->m_mode |= mode_mask[(q - mode_chars) - i];
266 /* Now get the the user/group info. */
268 s = skip_whitespace(e);
270 /* Note: we require whitespace between the mode and the
271 * user/group info. */
272 if ((s == e) || !(e = strchr(s, '.'))) {
273 parse_error("<uid>.<gid>");
277 /* We can't use get_ug_id here since it would exit()
278 * if a uid or gid was not found. Oh well... */
279 sct->m_uid = bb_strtoul(s, NULL, 10);
281 struct passwd *pwd = getpwnam(s);
285 sct->m_uid = pwd->pw_uid;
288 sct->m_gid = bb_strtoul(e, NULL, 10);
293 parse_error("group");
295 sct->m_gid = grp->gr_gid;
301 /* Unknown sections are ignored. */
303 /* Encountering configuration lines prior to seeing a
304 * section header is treated as an error. This is how
305 * the old code worked, but it may not be desirable.
306 * We may want to simply ignore such lines in case they
307 * are used in some future version of busybox. */
309 parse_error("keyword outside section");
315 fprintf(stderr, "Parse error in %s, line %d: %s\n",
316 config_file, lc, errmsg);
319 /* Release any allocated memory before returning. */
321 sct = sct_head->m_next;
327 #define parse_config_file() ((void)0)
328 #endif /* FEATURE_SUID_CONFIG */
331 #if ENABLE_FEATURE_SUID
332 static void check_suid(const struct bb_applet *applet)
334 uid_t ruid = getuid(); /* real [ug]id */
335 uid_t rgid = getgid();
337 #if ENABLE_FEATURE_SUID_CONFIG
338 if (suid_cfg_readable) {
339 struct BB_suid_config *sct;
342 for (sct = suid_config; sct; sct = sct->m_next) {
343 if (sct->m_applet == applet)
346 /* default: drop all privileges */
352 if (sct->m_uid == ruid)
355 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
356 /* same group / in group */
359 if (!(m & S_IXOTH)) /* is x bit not set ? */
360 bb_error_msg_and_die("you have no permission to run this applet!");
362 if (sct->m_gid != 0) {
363 /* _both_ have to be set for sgid */
364 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
366 } else xsetgid(rgid); /* no sgid -> drop */
368 if (sct->m_uid != 0) {
369 if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
370 else xsetuid(ruid); /* no suid -> drop */
374 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
376 static bool onetime = 0;
380 fprintf(stderr, "Using fallback suid method\n");
386 if (applet->need_suid == _BB_SUID_ALWAYS) {
388 bb_error_msg_and_die("applet requires root privileges!");
389 } else if (applet->need_suid == _BB_SUID_NEVER) {
390 xsetgid(rgid); /* drop all privileges */
395 #define check_suid(x) ((void)0)
396 #endif /* FEATURE_SUID */
399 #if ENABLE_FEATURE_COMPRESS_USAGE
401 #include "usage_compressed.h"
402 #include "unarchive.h"
404 static const char *unpack_usage_messages(void)
410 i = start_bunzip(&bd,
412 /* inbuf: */ packed_usage,
413 /* len: */ sizeof(packed_usage));
414 /* read_bunzip can longjmp to start_bunzip, and ultimately
415 * end up here with i != 0 on read data errors! Not trivial */
417 /* Cannot use xmalloc: will leak bd in NOFORK case! */
418 outbuf = malloc_or_warn(SIZEOF_usage_messages);
420 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
425 #define dealloc_usage_messages(s) free(s)
429 #define unpack_usage_messages() usage_messages
430 #define dealloc_usage_messages(s) ((void)(s))
432 #endif /* FEATURE_COMPRESS_USAGE */
435 void bb_show_usage(void)
437 if (ENABLE_SHOW_USAGE) {
438 const char *format_string;
440 const char *usage_string = p = unpack_usage_messages();
443 i = current_applet - applets;
445 while (*p++) continue;
449 format_string = "%s\n\nUsage: %s %s\n\n";
451 format_string = "%s\n\nNo help available.\n\n";
452 fprintf(stderr, format_string, bb_msg_full_version,
454 dealloc_usage_messages((char*)usage_string);
460 static int applet_name_compare(const void *name, const void *vapplet)
462 const struct bb_applet *applet = vapplet;
464 return strcmp(name, applet->name);
467 const struct bb_applet *find_applet_by_name(const char *name)
469 /* Do a binary search to find the applet entry given the name. */
470 return bsearch(name, applets, NUM_APPLETS, sizeof(applets[0]),
471 applet_name_compare);
475 #if ENABLE_FEATURE_INSTALLER
476 /* create (sym)links for each applet */
477 static void install_links(const char *busybox, int use_symbolic_links)
480 * this should be consistent w/ the enum,
481 * busybox.h::bb_install_loc_t, or else... */
482 static const char usr_bin [] = "/usr/bin";
483 static const char usr_sbin[] = "/usr/sbin";
484 static const char *const install_dir[] = {
485 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
486 &usr_bin [4], /* "/bin" */
487 &usr_sbin[4], /* "/sbin" */
492 int (*lf)(const char *, const char *) = link;
497 if (use_symbolic_links)
500 for (i = 0; applets[i].name != NULL; i++) {
501 fpc = concat_path_file(
502 install_dir[applets[i].install_loc],
504 rc = lf(busybox, fpc);
505 if (rc != 0 && errno != EEXIST) {
506 bb_perror_msg("%s", fpc);
512 #define install_links(x,y) ((void)0)
513 #endif /* FEATURE_INSTALLER */
516 /* If we were called as "busybox..." */
517 static int busybox_main(int argc, char **argv)
519 if (ENABLE_FEATURE_INSTALLER && argc > 1 && !strcmp(argv[1], "--install")) {
520 int use_symbolic_links = 0;
523 /* to use symlinks, or not to use symlinks... */
525 if (strcmp(argv[2], "-s") == 0)
526 use_symbolic_links = 1;
529 busybox = xmalloc_readlink_or_warn("/proc/self/exe");
532 install_links(busybox, use_symbolic_links);
533 if (ENABLE_FEATURE_CLEAN_UP)
538 /* Deal with --help. Also print help when called with no arguments */
540 if (argc == 1 || !strcmp(argv[1], "--help") ) {
542 /* set name for proper "<name>: applet not found" */
543 applet_name = argv[2];
544 run_applet_and_exit(applet_name, 2, argv);
546 const struct bb_applet *a;
547 int col, output_width;
549 output_width = 80 - sizeof("start-stop-daemon, ") - 8;
550 if (ENABLE_FEATURE_AUTOWIDTH) {
551 /* Obtain the terminal width. */
552 get_terminal_width_height(0, &output_width, NULL);
553 /* leading tab and room to wrap */
554 output_width -= sizeof("start-stop-daemon, ") + 8;
558 "Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n"
559 "Licensed under GPLv2. See source distribution for full notice.\n"
561 "Usage: busybox [function] [arguments]...\n"
562 " or: [function] [arguments]...\n"
564 "\tBusyBox is a multi-call binary that combines many common Unix\n"
565 "\tutilities into a single executable. Most people will create a\n"
566 "\tlink to busybox for each function they wish to use and BusyBox\n"
567 "\twill act like whatever it was invoked as!\n"
568 "\nCurrently defined functions:\n", bb_msg_full_version);
572 col += printf("%s%s", (col ? ", " : "\t"), a->name);
574 if (col > output_width && a->name) {
583 /* we want "<argv[1]>: applet not found", not "busybox: ..." */
584 applet_name = argv[1];
585 run_applet_and_exit(argv[1], argc - 1, argv + 1);
588 bb_error_msg_and_die("applet not found");
591 void run_current_applet_and_exit(int argc, char **argv)
593 /* Reinit some shared global data */
595 xfunc_error_retval = EXIT_FAILURE;
597 applet_name = current_applet->name;
598 if (argc == 2 && !strcmp(argv[1], "--help"))
600 if (ENABLE_FEATURE_SUID)
601 check_suid(current_applet);
602 exit(current_applet->main(argc, argv));
605 void run_applet_and_exit(const char *name, int argc, char **argv)
607 current_applet = find_applet_by_name(name);
609 run_current_applet_and_exit(argc, argv);
610 if (!strncmp(name, "busybox", 7))
611 exit(busybox_main(argc, argv));
615 int main(int argc, char **argv)
620 /* NOMMU re-exec trick sets high-order bit in first byte of name */
621 if (argv[0][0] & 0x80) {
626 applet_name = argv[0];
627 if (applet_name[0] == '-')
629 s = strrchr(applet_name, '/');
633 if (ENABLE_FEATURE_SUID_CONFIG)
636 /* Set locale for everybody except 'init' */
637 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
638 setlocale(LC_ALL, "");
640 run_applet_and_exit(applet_name, argc, argv);
641 bb_error_msg_and_die("applet not found");