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 */
37 /* Try to pull in PAGE_SIZE */
39 # include <sys/user.h>
41 #ifdef __GNU__ /* Hurd */
42 # include <mach/vm_param.h>
45 # define PAGE_SIZE (4*1024) /* guess */
49 /* Declare <applet>_main() */
54 /* Include generated applet names, pointers to <applet>_main, etc */
55 #include "applet_tables.h"
56 /* ...and if applet_tables generator says we have only one applet... */
57 #ifdef SINGLE_APPLET_MAIN
58 # undef ENABLE_FEATURE_INDIVIDUAL
59 # define ENABLE_FEATURE_INDIVIDUAL 1
60 # undef IF_FEATURE_INDIVIDUAL
61 # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
64 #include "usage_compressed.h"
67 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
68 static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
70 # define usage_messages 0
73 #if ENABLE_FEATURE_COMPRESS_USAGE
75 static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
77 static const char *unpack_usage_messages(void)
85 /* inbuf: */ packed_usage,
86 /* len: */ sizeof(packed_usage));
87 /* read_bunzip can longjmp to start_bunzip, and ultimately
88 * end up here with i != 0 on read data errors! Not trivial */
90 /* Cannot use xmalloc: will leak bd in NOFORK case! */
91 outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
93 read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
98 # define dealloc_usage_messages(s) free(s)
102 # define unpack_usage_messages() usage_messages
103 # define dealloc_usage_messages(s) ((void)(s))
105 #endif /* FEATURE_COMPRESS_USAGE */
108 void FAST_FUNC bb_show_usage(void)
110 if (ENABLE_SHOW_USAGE) {
111 #ifdef SINGLE_APPLET_STR
112 /* Imagine that this applet is "true". Dont suck in printf! */
113 const char *usage_string = unpack_usage_messages();
115 if (*usage_string == '\b') {
116 full_write2_str("No help available.\n\n");
118 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
119 full_write2_str(usage_string);
120 full_write2_str("\n\n");
122 if (ENABLE_FEATURE_CLEAN_UP)
123 dealloc_usage_messages((char*)usage_string);
126 const char *usage_string = p = unpack_usage_messages();
127 int ap = find_applet_by_name(applet_name);
129 if (ap < 0) /* never happens, paranoia */
132 while (*p++) continue;
135 full_write2_str(bb_banner);
136 full_write2_str(" multi-call binary.\n");
138 full_write2_str("\nNo help available.\n\n");
140 full_write2_str("\nUsage: ");
141 full_write2_str(applet_name);
142 full_write2_str(" ");
144 full_write2_str("\n\n");
146 if (ENABLE_FEATURE_CLEAN_UP)
147 dealloc_usage_messages((char*)usage_string);
154 /* NB: any char pointer will work as well, not necessarily applet_names */
155 static int applet_name_compare(const void *name, const void *v)
157 int i = (const char *)v - applet_names;
158 return strcmp(name, APPLET_NAME(i));
161 int FAST_FUNC find_applet_by_name(const char *name)
164 /* Do a binary search to find the applet entry given the name. */
166 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
169 return p - applet_names;
171 /* A version which does not pull in bsearch */
173 const char *p = applet_names;
174 while (i < NUM_APPLETS) {
175 if (strcmp(name, p) == 0)
185 void lbb_prepare(const char *applet
186 IF_FEATURE_INDIVIDUAL(, char **argv))
187 MAIN_EXTERNALLY_VISIBLE;
188 void lbb_prepare(const char *applet
189 IF_FEATURE_INDIVIDUAL(, char **argv))
192 (*(int **)&bb_errno) = __errno_location();
195 applet_name = applet;
197 /* Set locale for everybody except 'init' */
198 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
199 setlocale(LC_ALL, "");
201 #if ENABLE_FEATURE_INDIVIDUAL
202 /* Redundant for busybox (run_applet_and_exit covers that case)
203 * but needed for "individual applet" mode */
206 && strcmp(argv[1], "--help") == 0
207 && strncmp(applet, "busybox", 7) != 0
209 /* Special case. POSIX says "test --help"
210 * should be no different from e.g. "test --foo". */
211 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
217 /* The code below can well be in applets/applets.c, as it is used only
218 * for busybox binary, not "individual" binaries.
219 * However, keeping it here and linking it into libbusybox.so
220 * (together with remaining tiny applets/applets.o)
221 * makes it possible to avoid --whole-archive at link time.
222 * This makes (shared busybox) + libbusybox smaller.
223 * (--gc-sections would be even better....)
226 const char *applet_name;
232 /* If not built as a single-applet executable... */
233 #if !defined(SINGLE_APPLET_MAIN)
235 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
237 # if ENABLE_FEATURE_SUID_CONFIG
239 static struct suid_config_t {
240 /* next ptr must be first: this struct needs to be llist-compatible */
241 struct suid_config_t *m_next;
242 struct bb_uidgid_t m_ugid;
247 static bool suid_cfg_readable;
249 /* check if u is member of group g */
250 static int ingroup(uid_t u, gid_t g)
252 struct group *grp = getgrgid(g);
255 for (mem = grp->gr_mem; *mem; mem++) {
256 struct passwd *pwd = getpwnam(*mem);
257 if (pwd && (pwd->pw_uid == u))
264 /* libbb candidate */
265 static char *get_trimmed_slice(char *s, char *e)
267 /* First, consider the value at e to be nul and back up until we
268 * reach a non-space char. Set the char after that (possibly at
269 * the original e) to nul. */
277 /* Next, advance past all leading space and return a ptr to the
278 * first non-space char; possibly the terminating nul. */
279 return skip_whitespace(s);
282 static void parse_config_file(void)
284 /* Don't depend on the tools to combine strings. */
285 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
287 struct suid_config_t *sct_head;
296 if (ruid == 0) /* run by root - don't need to even read config file */
299 if ((stat(config_file, &st) != 0) /* No config file? */
300 || !S_ISREG(st.st_mode) /* Not a regular file? */
301 || (st.st_uid != 0) /* Not owned by root? */
302 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
303 || !(f = fopen_for_read(config_file)) /* Cannot open? */
308 suid_cfg_readable = 1;
316 if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
318 //if (ferror(f)) { /* Make sure it wasn't a read error. */
319 // errmsg = "reading";
323 suid_config = sct_head; /* Success, so set the pointer. */
328 lc++; /* Got a (partial) line. */
330 /* If a line is too long for our buffer, we consider it an error.
331 * The following test does mistreat one corner case though.
332 * If the final line of the file does not end with a newline and
333 * yet exactly fills the buffer, it will be treated as too long
334 * even though there isn't really a problem. But it isn't really
335 * worth adding code to deal with such an unlikely situation, and
336 * we do err on the side of caution. Besides, the line would be
337 * too long if it did end with a newline. */
338 if (!strchr(s, '\n') && !feof(f)) {
339 errmsg = "line too long";
343 /* Trim leading and trailing whitespace, ignoring comments, and
344 * check if the resulting string is empty. */
345 s = get_trimmed_slice(s, strchrnul(s, '#'));
350 /* Check for a section header. */
353 /* Unlike the old code, we ignore leading and trailing
354 * whitespace for the section name. We also require that
355 * there are no stray characters after the closing bracket. */
356 char *e = strchr(s, ']');
357 if (!e /* Missing right bracket? */
358 || e[1] /* Trailing characters? */
359 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
361 errmsg = "section header";
364 /* Right now we only have one section so just check it.
365 * If more sections are added in the future, please don't
366 * resort to cascading ifs with multiple strcasecmp calls.
367 * That kind of bloated code is all too common. A loop
368 * and a string table would be a better choice unless the
369 * number of sections is very small. */
370 if (strcasecmp(s, "SUID") == 0) {
374 section = -1; /* Unknown section so set to skip. */
378 /* Process sections. */
380 if (section == 1) { /* SUID */
381 /* Since we trimmed leading and trailing space above, we're
382 * now looking for strings of the form
383 * <key>[::space::]*=[::space::]*<value>
384 * where both key and value could contain inner whitespace. */
386 /* First get the key (an applet name in our case). */
387 char *e = strchr(s, '=');
389 s = get_trimmed_slice(s, e);
391 if (!e || !*s) { /* Missing '=' or empty key. */
396 /* Ok, we have an applet name. Process the rhs if this
397 * applet is currently built in and ignore it otherwise.
398 * Note: this can hide config file bugs which only pop
399 * up when the busybox configuration is changed. */
400 applet_no = find_applet_by_name(s);
401 if (applet_no >= 0) {
403 struct suid_config_t *sct;
405 /* Note: We currently don't check for duplicates!
406 * The last config line for each applet will be the
407 * one used since we insert at the head of the list.
408 * I suppose this could be considered a feature. */
409 sct = xzalloc(sizeof(*sct));
410 sct->m_applet = applet_no;
412 sct->m_next = sct_head;
415 /* Get the specified mode. */
417 e = skip_whitespace(e+1);
419 for (i = 0; i < 3; i++) {
420 /* There are 4 chars for each of user/group/other.
421 * "x-xx" instead of "x-" are to make
422 * "idx > 3" check catch invalid chars.
424 static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
425 static const unsigned short mode_mask[] ALIGN2 = {
426 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
427 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
430 const char *q = strchrnul(mode_chars + 4*i, *e);
431 unsigned idx = q - (mode_chars + 4*i);
436 sct->m_mode |= mode_mask[q - mode_chars];
440 /* Now get the user/group info. */
442 s = skip_whitespace(e);
444 s = strcpy(buffer, "0.0");
446 /* We require whitespace between mode and USER.GROUP */
447 if ((s == e) || !(e = strchr(s, '.'))) {
452 *e = ':'; /* get_uidgid needs USER:GROUP syntax */
453 if (get_uidgid(&sct->m_ugid, s, /*allow_numeric:*/ 1) == 0) {
454 errmsg = "unknown user/group";
461 /* Unknown sections are ignored. */
463 /* Encountering configuration lines prior to seeing a
464 * section header is treated as an error. This is how
465 * the old code worked, but it may not be desirable.
466 * We may want to simply ignore such lines in case they
467 * are used in some future version of busybox. */
469 errmsg = "keyword outside section";
477 bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
479 /* Release any allocated memory before returning. */
480 llist_free((llist_t*)sct_head, NULL);
483 static inline void parse_config_file(void)
485 IF_FEATURE_SUID(ruid = getuid();)
487 # endif /* FEATURE_SUID_CONFIG */
490 # if ENABLE_FEATURE_SUID
491 static void check_suid(int applet_no)
493 gid_t rgid; /* real gid */
495 if (ruid == 0) /* set by parse_config_file() */
496 return; /* run by root - no need to check more */
499 # if ENABLE_FEATURE_SUID_CONFIG
500 if (suid_cfg_readable) {
502 struct suid_config_t *sct;
505 for (sct = suid_config; sct; sct = sct->m_next) {
506 if (sct->m_applet == applet_no)
509 goto check_need_suid;
511 /* Is this user allowed to run this applet? */
513 if (sct->m_ugid.uid == ruid)
516 else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
517 /* same group / in group */
519 if (!(m & S_IXOTH)) /* is x bit not set? */
520 bb_error_msg_and_die("you have no permission to run this applet");
522 /* We set effective AND saved ids. If saved-id is not set
523 * like we do below, seteuid(0) can still later succeed! */
525 /* Are we directed to change gid
526 * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
528 if (sct->m_mode & S_ISGID)
529 rgid = sct->m_ugid.gid;
530 /* else: we will set egid = rgid, thus dropping sgid effect */
531 if (setresgid(-1, rgid, rgid))
532 bb_perror_msg_and_die("setresgid");
534 /* Are we directed to change uid
535 * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
538 if (sct->m_mode & S_ISUID)
539 uid = sct->m_ugid.uid;
540 /* else: we will set euid = ruid, thus dropping suid effect */
541 if (setresuid(-1, uid, uid))
542 bb_perror_msg_and_die("setresuid");
546 # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
548 static bool onetime = 0;
552 bb_error_msg("using fallback suid method");
558 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
559 /* Real uid is not 0. If euid isn't 0 too, suid bit
560 * is most probably not set on our executable */
562 bb_error_msg_and_die("must be suid to work properly");
563 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
564 xsetgid(rgid); /* drop all privileges */
568 # if ENABLE_FEATURE_SUID_CONFIG
569 llist_free((llist_t*)suid_config, NULL);
573 # define check_suid(x) ((void)0)
574 # endif /* FEATURE_SUID */
577 # if ENABLE_FEATURE_INSTALLER
578 static const char usr_bin [] ALIGN1 = "/usr/bin/";
579 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
580 static const char *const install_dir[] = {
581 &usr_bin [8], /* "/" */
582 &usr_bin [4], /* "/bin/" */
583 &usr_sbin[4] /* "/sbin/" */
584 # if !ENABLE_INSTALL_NO_USR
590 /* create (sym)links for each applet */
591 static void install_links(const char *busybox, int use_symbolic_links,
592 char *custom_install_dir)
595 * this should be consistent w/ the enum,
596 * busybox.h::bb_install_loc_t, or else... */
597 int (*lf)(const char *, const char *);
603 if (use_symbolic_links)
606 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
607 fpc = concat_path_file(
608 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
610 // debug: bb_error_msg("%slinking %s to busybox",
611 // use_symbolic_links ? "sym" : "", fpc);
612 rc = lf(busybox, fpc);
613 if (rc != 0 && errno != EEXIST) {
614 bb_simple_perror_msg(fpc);
620 # define install_links(x,y,z) ((void)0)
623 /* If we were called as "busybox..." */
624 static int busybox_main(char **argv)
627 /* Called without arguments */
630 unsigned output_width;
633 if (ENABLE_FEATURE_AUTOWIDTH) {
634 /* Obtain the terminal width */
635 get_terminal_width_height(0, &output_width, NULL);
639 full_write2_str(bb_banner); /* reuse const string */
640 full_write2_str(" multi-call binary.\n"); /* reuse */
642 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
643 "and others. Licensed under GPLv2.\n"
644 "See source distribution for full notice.\n"
646 "Usage: busybox [function] [arguments]...\n"
647 " or: busybox --list[-full]\n"
648 " or: function [arguments]...\n"
650 "\tBusyBox is a multi-call binary that combines many common Unix\n"
651 "\tutilities into a single executable. Most people will create a\n"
652 "\tlink to busybox for each function they wish to use and BusyBox\n"
653 "\twill act like whatever it was invoked as.\n"
655 "Currently defined functions:\n"
659 /* prevent last comma to be in the very last pos */
662 int len2 = strlen(a) + 2;
663 if (col >= (int)output_width - len2) {
664 full_write2_str(",\n");
669 full_write2_str("\t");
671 full_write2_str(", ");
677 full_write2_str("\n\n");
681 if (strncmp(argv[1], "--list", 6) == 0) {
683 const char *a = applet_names;
686 # if ENABLE_FEATURE_INSTALLER
687 if (argv[1][6]) /* --list-path? */
688 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
691 full_write2_str("\n");
698 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
699 int use_symbolic_links;
702 busybox = xmalloc_readlink(bb_busybox_exec_path);
704 /* bb_busybox_exec_path is usually "/proc/self/exe".
705 * In chroot, readlink("/proc/self/exe") usually fails.
706 * In such case, better use argv[0] as symlink target
707 * if it is a full path name.
709 if (argv[0][0] != '/')
710 bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
713 /* busybox --install [-s] [DIR]:
715 * DIR: directory to install links to
717 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
718 install_links(busybox, use_symbolic_links, argv[2]);
722 if (strcmp(argv[1], "--help") == 0) {
723 /* "busybox --help [<applet>]" */
726 /* convert to "<applet> --help" */
730 /* "busybox <applet> arg1 arg2 ..." */
733 /* We support "busybox /a/path/to/applet args..." too. Allows for
734 * "#!/bin/busybox"-style wrappers */
735 applet_name = bb_get_last_path_component_nostrip(argv[0]);
736 run_applet_and_exit(applet_name, argv);
738 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
739 full_write2_str(applet_name);
740 full_write2_str(": applet not found\n");
744 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
751 /* Reinit some shared global data */
752 xfunc_error_retval = EXIT_FAILURE;
754 applet_name = APPLET_NAME(applet_no);
755 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
756 /* Special case. POSIX says "test --help"
757 * should be no different from e.g. "test --foo". */
758 //TODO: just compare applet_no with APPLET_NO_test
759 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
762 if (ENABLE_FEATURE_SUID)
763 check_suid(applet_no);
764 exit(applet_main[applet_no](argc, argv));
767 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
769 int applet = find_applet_by_name(name);
771 run_applet_no_and_exit(applet, argv);
772 if (strncmp(name, "busybox", 7) == 0)
773 exit(busybox_main(argv));
776 #endif /* !defined(SINGLE_APPLET_MAIN) */
780 #if ENABLE_BUILD_LIBBUSYBOX
781 int lbb_main(char **argv)
783 int main(int argc UNUSED_PARAM, char **argv)
786 /* Tweak malloc for reduced memory consumption */
787 #ifdef M_TRIM_THRESHOLD
788 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
789 * to keep before releasing to the OS
790 * Default is way too big: 256k
792 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
794 #ifdef M_MMAP_THRESHOLD
795 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
796 * Default is too big: 256k
798 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
802 /* NOMMU re-exec trick sets high-order bit in first byte of name */
803 if (argv[0][0] & 0x80) {
809 #if defined(SINGLE_APPLET_MAIN)
810 /* Only one applet is selected in .config */
811 if (argv[1] && strncmp(argv[0], "busybox", 7) == 0) {
812 /* "busybox <applet> <params>" should still work as expected */
815 /* applet_names in this case is just "applet\0\0" */
816 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
817 return SINGLE_APPLET_MAIN(argc, argv);
819 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
821 applet_name = argv[0];
822 if (applet_name[0] == '-')
824 applet_name = bb_basename(applet_name);
826 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
828 run_applet_and_exit(applet_name, argv);
830 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
831 full_write2_str(applet_name);
832 full_write2_str(": applet not found\n");