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 GPL.
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
15 /* We are trying to not use printf, this benefits the case when selected
16 * applets are really simple. Example:
20 * Currently defined functions:
21 * basename, false, true
24 * text data bss dec hex filename
25 * 4473 52 72 4597 11f5 busybox
27 * FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
31 #if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
32 || defined(__APPLE__) \
34 # include <malloc.h> /* for mallopt */
38 /* Declare <applet>_main() */
43 /* Include generated applet names, pointers to <applet>_main, etc */
44 #include "applet_tables.h"
45 /* ...and if applet_tables generator says we have only one applet... */
46 #ifdef SINGLE_APPLET_MAIN
47 # undef ENABLE_FEATURE_INDIVIDUAL
48 # define ENABLE_FEATURE_INDIVIDUAL 1
49 # undef IF_FEATURE_INDIVIDUAL
50 # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
53 #include "usage_compressed.h"
56 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
57 static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
59 # define usage_messages 0
62 #if ENABLE_FEATURE_COMPRESS_USAGE
64 static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
65 # include "bb_archive.h"
66 static const char *unpack_usage_messages(void)
74 /* inbuf: */ packed_usage,
75 /* len: */ sizeof(packed_usage));
76 /* read_bunzip can longjmp to start_bunzip, and ultimately
77 * end up here with i != 0 on read data errors! Not trivial */
79 /* Cannot use xmalloc: will leak bd in NOFORK case! */
80 outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
82 read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
87 # define dealloc_usage_messages(s) free(s)
91 # define unpack_usage_messages() usage_messages
92 # define dealloc_usage_messages(s) ((void)(s))
94 #endif /* FEATURE_COMPRESS_USAGE */
97 void FAST_FUNC bb_show_usage(void)
99 if (ENABLE_SHOW_USAGE) {
100 #ifdef SINGLE_APPLET_STR
101 /* Imagine that this applet is "true". Dont suck in printf! */
102 const char *usage_string = unpack_usage_messages();
104 if (*usage_string == '\b') {
105 full_write2_str("No help available.\n\n");
107 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
108 full_write2_str(usage_string);
109 full_write2_str("\n\n");
111 if (ENABLE_FEATURE_CLEAN_UP)
112 dealloc_usage_messages((char*)usage_string);
115 const char *usage_string = p = unpack_usage_messages();
116 int ap = find_applet_by_name(applet_name);
118 if (ap < 0) /* never happens, paranoia */
121 while (*p++) continue;
124 full_write2_str(bb_banner);
125 full_write2_str(" multi-call binary.\n");
127 full_write2_str("\nNo help available.\n\n");
129 full_write2_str("\nUsage: ");
130 full_write2_str(applet_name);
131 full_write2_str(" ");
133 full_write2_str("\n\n");
135 if (ENABLE_FEATURE_CLEAN_UP)
136 dealloc_usage_messages((char*)usage_string);
143 /* NB: any char pointer will work as well, not necessarily applet_names */
144 static int applet_name_compare(const void *name, const void *v)
146 int i = (const char *)v - applet_names;
147 return strcmp(name, APPLET_NAME(i));
150 int FAST_FUNC find_applet_by_name(const char *name)
153 /* Do a binary search to find the applet entry given the name. */
155 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
158 return p - applet_names;
160 /* A version which does not pull in bsearch */
162 const char *p = applet_names;
163 while (i < NUM_APPLETS) {
164 if (strcmp(name, p) == 0)
174 void lbb_prepare(const char *applet
175 IF_FEATURE_INDIVIDUAL(, char **argv))
176 MAIN_EXTERNALLY_VISIBLE;
177 void lbb_prepare(const char *applet
178 IF_FEATURE_INDIVIDUAL(, char **argv))
181 (*(int **)&bb_errno) = __errno_location();
184 applet_name = applet;
186 /* Set locale for everybody except 'init' */
187 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
188 setlocale(LC_ALL, "");
190 #if ENABLE_FEATURE_INDIVIDUAL
191 /* Redundant for busybox (run_applet_and_exit covers that case)
192 * but needed for "individual applet" mode */
195 && strcmp(argv[1], "--help") == 0
196 && strncmp(applet, "busybox", 7) != 0
198 /* Special case. POSIX says "test --help"
199 * should be no different from e.g. "test --foo". */
200 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
206 /* The code below can well be in applets/applets.c, as it is used only
207 * for busybox binary, not "individual" binaries.
208 * However, keeping it here and linking it into libbusybox.so
209 * (together with remaining tiny applets/applets.o)
210 * makes it possible to avoid --whole-archive at link time.
211 * This makes (shared busybox) + libbusybox smaller.
212 * (--gc-sections would be even better....)
215 const char *applet_name;
221 /* If not built as a single-applet executable... */
222 #if !defined(SINGLE_APPLET_MAIN)
224 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
226 # if ENABLE_FEATURE_SUID_CONFIG
228 static struct suid_config_t {
229 /* next ptr must be first: this struct needs to be llist-compatible */
230 struct suid_config_t *m_next;
231 struct bb_uidgid_t m_ugid;
236 static bool suid_cfg_readable;
238 /* check if u is member of group g */
239 static int ingroup(uid_t u, gid_t g)
241 struct group *grp = getgrgid(g);
244 for (mem = grp->gr_mem; *mem; mem++) {
245 struct passwd *pwd = getpwnam(*mem);
246 if (pwd && (pwd->pw_uid == u))
253 /* libbb candidate */
254 static char *get_trimmed_slice(char *s, char *e)
256 /* First, consider the value at e to be nul and back up until we
257 * reach a non-space char. Set the char after that (possibly at
258 * the original e) to nul. */
266 /* Next, advance past all leading space and return a ptr to the
267 * first non-space char; possibly the terminating nul. */
268 return skip_whitespace(s);
271 static void parse_config_file(void)
273 /* Don't depend on the tools to combine strings. */
274 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
276 struct suid_config_t *sct_head;
285 if (ruid == 0) /* run by root - don't need to even read config file */
288 if ((stat(config_file, &st) != 0) /* No config file? */
289 || !S_ISREG(st.st_mode) /* Not a regular file? */
290 || (st.st_uid != 0) /* Not owned by root? */
291 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
292 || !(f = fopen_for_read(config_file)) /* Cannot open? */
297 suid_cfg_readable = 1;
305 if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
307 //if (ferror(f)) { /* Make sure it wasn't a read error. */
308 // errmsg = "reading";
312 suid_config = sct_head; /* Success, so set the pointer. */
317 lc++; /* Got a (partial) line. */
319 /* If a line is too long for our buffer, we consider it an error.
320 * The following test does mistreat one corner case though.
321 * If the final line of the file does not end with a newline and
322 * yet exactly fills the buffer, it will be treated as too long
323 * even though there isn't really a problem. But it isn't really
324 * worth adding code to deal with such an unlikely situation, and
325 * we do err on the side of caution. Besides, the line would be
326 * too long if it did end with a newline. */
327 if (!strchr(s, '\n') && !feof(f)) {
328 errmsg = "line too long";
332 /* Trim leading and trailing whitespace, ignoring comments, and
333 * check if the resulting string is empty. */
334 s = get_trimmed_slice(s, strchrnul(s, '#'));
339 /* Check for a section header. */
342 /* Unlike the old code, we ignore leading and trailing
343 * whitespace for the section name. We also require that
344 * there are no stray characters after the closing bracket. */
345 char *e = strchr(s, ']');
346 if (!e /* Missing right bracket? */
347 || e[1] /* Trailing characters? */
348 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
350 errmsg = "section header";
353 /* Right now we only have one section so just check it.
354 * If more sections are added in the future, please don't
355 * resort to cascading ifs with multiple strcasecmp calls.
356 * That kind of bloated code is all too common. A loop
357 * and a string table would be a better choice unless the
358 * number of sections is very small. */
359 if (strcasecmp(s, "SUID") == 0) {
363 section = -1; /* Unknown section so set to skip. */
367 /* Process sections. */
369 if (section == 1) { /* SUID */
370 /* Since we trimmed leading and trailing space above, we're
371 * now looking for strings of the form
372 * <key>[::space::]*=[::space::]*<value>
373 * where both key and value could contain inner whitespace. */
375 /* First get the key (an applet name in our case). */
376 char *e = strchr(s, '=');
378 s = get_trimmed_slice(s, e);
380 if (!e || !*s) { /* Missing '=' or empty key. */
385 /* Ok, we have an applet name. Process the rhs if this
386 * applet is currently built in and ignore it otherwise.
387 * Note: this can hide config file bugs which only pop
388 * up when the busybox configuration is changed. */
389 applet_no = find_applet_by_name(s);
390 if (applet_no >= 0) {
392 struct suid_config_t *sct;
394 /* Note: We currently don't check for duplicates!
395 * The last config line for each applet will be the
396 * one used since we insert at the head of the list.
397 * I suppose this could be considered a feature. */
398 sct = xzalloc(sizeof(*sct));
399 sct->m_applet = applet_no;
401 sct->m_next = sct_head;
404 /* Get the specified mode. */
406 e = skip_whitespace(e+1);
408 for (i = 0; i < 3; i++) {
409 /* There are 4 chars for each of user/group/other.
410 * "x-xx" instead of "x-" are to make
411 * "idx > 3" check catch invalid chars.
413 static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
414 static const unsigned short mode_mask[] ALIGN2 = {
415 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
416 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
419 const char *q = strchrnul(mode_chars + 4*i, *e);
420 unsigned idx = q - (mode_chars + 4*i);
425 sct->m_mode |= mode_mask[q - mode_chars];
429 /* Now get the user/group info. */
431 s = skip_whitespace(e);
432 /* Default is 0.0, else parse USER.GROUP: */
434 /* We require whitespace between mode and USER.GROUP */
435 if ((s == e) || !(e = strchr(s, '.'))) {
439 *e = ':'; /* get_uidgid needs USER:GROUP syntax */
440 if (get_uidgid(&sct->m_ugid, s, /*allow_numeric:*/ 1) == 0) {
441 errmsg = "unknown user/group";
449 /* Unknown sections are ignored. */
451 /* Encountering configuration lines prior to seeing a
452 * section header is treated as an error. This is how
453 * the old code worked, but it may not be desirable.
454 * We may want to simply ignore such lines in case they
455 * are used in some future version of busybox. */
457 errmsg = "keyword outside section";
465 bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
467 /* Release any allocated memory before returning. */
468 llist_free((llist_t*)sct_head, NULL);
471 static inline void parse_config_file(void)
473 IF_FEATURE_SUID(ruid = getuid();)
475 # endif /* FEATURE_SUID_CONFIG */
478 # if ENABLE_FEATURE_SUID
479 static void check_suid(int applet_no)
481 gid_t rgid; /* real gid */
483 if (ruid == 0) /* set by parse_config_file() */
484 return; /* run by root - no need to check more */
487 # if ENABLE_FEATURE_SUID_CONFIG
488 if (suid_cfg_readable) {
490 struct suid_config_t *sct;
493 for (sct = suid_config; sct; sct = sct->m_next) {
494 if (sct->m_applet == applet_no)
497 goto check_need_suid;
499 /* Is this user allowed to run this applet? */
501 if (sct->m_ugid.uid == ruid)
504 else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
505 /* same group / in group */
507 if (!(m & S_IXOTH)) /* is x bit not set? */
508 bb_error_msg_and_die("you have no permission to run this applet");
510 /* We set effective AND saved ids. If saved-id is not set
511 * like we do below, seteuid(0) can still later succeed! */
513 /* Are we directed to change gid
514 * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
516 if (sct->m_mode & S_ISGID)
517 rgid = sct->m_ugid.gid;
518 /* else: we will set egid = rgid, thus dropping sgid effect */
519 if (setresgid(-1, rgid, rgid))
520 bb_perror_msg_and_die("setresgid");
522 /* Are we directed to change uid
523 * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
526 if (sct->m_mode & S_ISUID)
527 uid = sct->m_ugid.uid;
528 /* else: we will set euid = ruid, thus dropping suid effect */
529 if (setresuid(-1, uid, uid))
530 bb_perror_msg_and_die("setresuid");
534 # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
536 static bool onetime = 0;
540 bb_error_msg("using fallback suid method");
546 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
547 /* Real uid is not 0. If euid isn't 0 too, suid bit
548 * is most probably not set on our executable */
550 bb_error_msg_and_die("must be suid to work properly");
551 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
552 xsetgid(rgid); /* drop all privileges */
555 # if ENABLE_FEATURE_SUID_CONFIG
557 llist_free((llist_t*)suid_config, NULL);
561 # define check_suid(x) ((void)0)
562 # endif /* FEATURE_SUID */
565 # if ENABLE_FEATURE_INSTALLER
566 static const char usr_bin [] ALIGN1 = "/usr/bin/";
567 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
568 static const char *const install_dir[] = {
569 &usr_bin [8], /* "/" */
570 &usr_bin [4], /* "/bin/" */
571 &usr_sbin[4] /* "/sbin/" */
572 # if !ENABLE_INSTALL_NO_USR
578 /* create (sym)links for each applet */
579 static void install_links(const char *busybox, int use_symbolic_links,
580 char *custom_install_dir)
583 * this should be consistent w/ the enum,
584 * busybox.h::bb_install_loc_t, or else... */
585 int (*lf)(const char *, const char *);
591 if (use_symbolic_links)
594 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
595 fpc = concat_path_file(
596 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
598 // debug: bb_error_msg("%slinking %s to busybox",
599 // use_symbolic_links ? "sym" : "", fpc);
600 rc = lf(busybox, fpc);
601 if (rc != 0 && errno != EEXIST) {
602 bb_simple_perror_msg(fpc);
608 # define install_links(x,y,z) ((void)0)
611 /* If we were called as "busybox..." */
612 static int busybox_main(char **argv)
615 /* Called without arguments */
618 unsigned output_width;
621 if (ENABLE_FEATURE_AUTOWIDTH) {
622 /* Obtain the terminal width */
623 get_terminal_width_height(0, &output_width, NULL);
627 full_write2_str(bb_banner); /* reuse const string */
628 full_write2_str(" multi-call binary.\n"); /* reuse */
630 "BusyBox is copyrighted by many authors between 1998-2012.\n"
631 "Licensed under GPLv2. See source distribution for detailed\n"
632 "copyright notices.\n"
634 "Usage: busybox [function [arguments]...]\n"
635 " or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
636 IF_FEATURE_INSTALLER(
637 " or: busybox --install [-s] [DIR]\n"
639 " or: function [arguments]...\n"
641 "\tBusyBox is a multi-call binary that combines many common Unix\n"
642 "\tutilities into a single executable. Most people will create a\n"
643 "\tlink to busybox for each function they wish to use and BusyBox\n"
644 "\twill act like whatever it was invoked as.\n"
646 "Currently defined functions:\n"
650 /* prevent last comma to be in the very last pos */
653 int len2 = strlen(a) + 2;
654 if (col >= (int)output_width - len2) {
655 full_write2_str(",\n");
660 full_write2_str("\t");
662 full_write2_str(", ");
668 full_write2_str("\n\n");
672 if (strncmp(argv[1], "--list", 6) == 0) {
674 const char *a = applet_names;
677 # if ENABLE_FEATURE_INSTALLER
678 if (argv[1][6]) /* --list-full? */
679 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
682 full_write2_str("\n");
689 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
690 int use_symbolic_links;
693 busybox = xmalloc_readlink(bb_busybox_exec_path);
695 /* bb_busybox_exec_path is usually "/proc/self/exe".
696 * In chroot, readlink("/proc/self/exe") usually fails.
697 * In such case, better use argv[0] as symlink target
698 * if it is a full path name.
700 if (argv[0][0] != '/')
701 bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
704 /* busybox --install [-s] [DIR]:
706 * DIR: directory to install links to
708 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
709 install_links(busybox, use_symbolic_links, argv[2]);
713 if (strcmp(argv[1], "--help") == 0) {
714 /* "busybox --help [<applet>]" */
717 /* convert to "<applet> --help" */
721 /* "busybox <applet> arg1 arg2 ..." */
724 /* We support "busybox /a/path/to/applet args..." too. Allows for
725 * "#!/bin/busybox"-style wrappers */
726 applet_name = bb_get_last_path_component_nostrip(argv[0]);
727 run_applet_and_exit(applet_name, argv);
729 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
730 full_write2_str(applet_name);
731 full_write2_str(": applet not found\n");
735 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
742 /* Reinit some shared global data */
743 xfunc_error_retval = EXIT_FAILURE;
745 applet_name = APPLET_NAME(applet_no);
746 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
747 /* Special case. POSIX says "test --help"
748 * should be no different from e.g. "test --foo". */
749 //TODO: just compare applet_no with APPLET_NO_test
750 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
753 if (ENABLE_FEATURE_SUID)
754 check_suid(applet_no);
755 exit(applet_main[applet_no](argc, argv));
758 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
760 int applet = find_applet_by_name(name);
762 run_applet_no_and_exit(applet, argv);
763 if (strncmp(name, "busybox", 7) == 0)
764 exit(busybox_main(argv));
767 #endif /* !defined(SINGLE_APPLET_MAIN) */
771 #if ENABLE_BUILD_LIBBUSYBOX
772 int lbb_main(char **argv)
774 int main(int argc UNUSED_PARAM, char **argv)
777 /* Tweak malloc for reduced memory consumption */
778 #ifdef M_TRIM_THRESHOLD
779 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
780 * to keep before releasing to the OS
781 * Default is way too big: 256k
783 mallopt(M_TRIM_THRESHOLD, 8 * 1024);
785 #ifdef M_MMAP_THRESHOLD
786 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
787 * Default is too big: 256k
789 mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
793 /* NOMMU re-exec trick sets high-order bit in first byte of name */
794 if (argv[0][0] & 0x80) {
800 #if defined(SINGLE_APPLET_MAIN)
801 /* Only one applet is selected in .config */
802 if (argv[1] && strncmp(argv[0], "busybox", 7) == 0) {
803 /* "busybox <applet> <params>" should still work as expected */
806 /* applet_names in this case is just "applet\0\0" */
807 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
808 return SINGLE_APPLET_MAIN(argc, argv);
810 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
812 applet_name = argv[0];
813 if (applet_name[0] == '-')
815 applet_name = bb_basename(applet_name);
817 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
819 run_applet_and_exit(applet_name, argv);
821 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
822 full_write2_str(applet_name);
823 full_write2_str(": applet not found\n");