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 static int applet_name_compare(const void *name, const void *idx)
145 int i = (int)(ptrdiff_t)idx - 1;
146 return strcmp(name, APPLET_NAME(i));
149 int FAST_FUNC find_applet_by_name(const char *name)
152 /* Do a binary search to find the applet entry given the name. */
154 p = bsearch(name, (void*)(ptrdiff_t)1, ARRAY_SIZE(applet_main), 1, applet_name_compare);
157 * ^^^^^^^^^^^^^^^^^^ the code below will do this if p == NULL :)
159 return (int)(ptrdiff_t)p - 1;
161 /* A version which does not pull in bsearch */
163 const char *p = applet_names;
164 while (i < NUM_APPLETS) {
165 if (strcmp(name, p) == 0)
175 void lbb_prepare(const char *applet
176 IF_FEATURE_INDIVIDUAL(, char **argv))
177 MAIN_EXTERNALLY_VISIBLE;
178 void lbb_prepare(const char *applet
179 IF_FEATURE_INDIVIDUAL(, char **argv))
182 (*(int **)&bb_errno) = __errno_location();
185 applet_name = applet;
187 /* Set locale for everybody except 'init' */
188 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
189 setlocale(LC_ALL, "");
191 #if ENABLE_FEATURE_INDIVIDUAL
192 /* Redundant for busybox (run_applet_and_exit covers that case)
193 * but needed for "individual applet" mode */
196 && strcmp(argv[1], "--help") == 0
197 && strncmp(applet, "busybox", 7) != 0
199 /* Special case. POSIX says "test --help"
200 * should be no different from e.g. "test --foo". */
201 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
207 /* The code below can well be in applets/applets.c, as it is used only
208 * for busybox binary, not "individual" binaries.
209 * However, keeping it here and linking it into libbusybox.so
210 * (together with remaining tiny applets/applets.o)
211 * makes it possible to avoid --whole-archive at link time.
212 * This makes (shared busybox) + libbusybox smaller.
213 * (--gc-sections would be even better....)
216 const char *applet_name;
222 /* If not built as a single-applet executable... */
223 #if !defined(SINGLE_APPLET_MAIN)
225 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
227 # if ENABLE_FEATURE_SUID_CONFIG
229 static struct suid_config_t {
230 /* next ptr must be first: this struct needs to be llist-compatible */
231 struct suid_config_t *m_next;
232 struct bb_uidgid_t m_ugid;
237 static bool suid_cfg_readable;
239 /* check if u is member of group g */
240 static int ingroup(uid_t u, gid_t g)
242 struct group *grp = getgrgid(g);
245 for (mem = grp->gr_mem; *mem; mem++) {
246 struct passwd *pwd = getpwnam(*mem);
247 if (pwd && (pwd->pw_uid == u))
254 /* libbb candidate */
255 static char *get_trimmed_slice(char *s, char *e)
257 /* First, consider the value at e to be nul and back up until we
258 * reach a non-space char. Set the char after that (possibly at
259 * the original e) to nul. */
267 /* Next, advance past all leading space and return a ptr to the
268 * first non-space char; possibly the terminating nul. */
269 return skip_whitespace(s);
272 static void parse_config_file(void)
274 /* Don't depend on the tools to combine strings. */
275 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
277 struct suid_config_t *sct_head;
286 if (ruid == 0) /* run by root - don't need to even read config file */
289 if ((stat(config_file, &st) != 0) /* No config file? */
290 || !S_ISREG(st.st_mode) /* Not a regular file? */
291 || (st.st_uid != 0) /* Not owned by root? */
292 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
293 || !(f = fopen_for_read(config_file)) /* Cannot open? */
298 suid_cfg_readable = 1;
306 if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
308 //if (ferror(f)) { /* Make sure it wasn't a read error. */
309 // errmsg = "reading";
313 suid_config = sct_head; /* Success, so set the pointer. */
318 lc++; /* Got a (partial) line. */
320 /* If a line is too long for our buffer, we consider it an error.
321 * The following test does mistreat one corner case though.
322 * If the final line of the file does not end with a newline and
323 * yet exactly fills the buffer, it will be treated as too long
324 * even though there isn't really a problem. But it isn't really
325 * worth adding code to deal with such an unlikely situation, and
326 * we do err on the side of caution. Besides, the line would be
327 * too long if it did end with a newline. */
328 if (!strchr(s, '\n') && !feof(f)) {
329 errmsg = "line too long";
333 /* Trim leading and trailing whitespace, ignoring comments, and
334 * check if the resulting string is empty. */
335 s = get_trimmed_slice(s, strchrnul(s, '#'));
340 /* Check for a section header. */
343 /* Unlike the old code, we ignore leading and trailing
344 * whitespace for the section name. We also require that
345 * there are no stray characters after the closing bracket. */
346 char *e = strchr(s, ']');
347 if (!e /* Missing right bracket? */
348 || e[1] /* Trailing characters? */
349 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
351 errmsg = "section header";
354 /* Right now we only have one section so just check it.
355 * If more sections are added in the future, please don't
356 * resort to cascading ifs with multiple strcasecmp calls.
357 * That kind of bloated code is all too common. A loop
358 * and a string table would be a better choice unless the
359 * number of sections is very small. */
360 if (strcasecmp(s, "SUID") == 0) {
364 section = -1; /* Unknown section so set to skip. */
368 /* Process sections. */
370 if (section == 1) { /* SUID */
371 /* Since we trimmed leading and trailing space above, we're
372 * now looking for strings of the form
373 * <key>[::space::]*=[::space::]*<value>
374 * where both key and value could contain inner whitespace. */
376 /* First get the key (an applet name in our case). */
377 char *e = strchr(s, '=');
379 s = get_trimmed_slice(s, e);
381 if (!e || !*s) { /* Missing '=' or empty key. */
386 /* Ok, we have an applet name. Process the rhs if this
387 * applet is currently built in and ignore it otherwise.
388 * Note: this can hide config file bugs which only pop
389 * up when the busybox configuration is changed. */
390 applet_no = find_applet_by_name(s);
391 if (applet_no >= 0) {
393 struct suid_config_t *sct;
395 /* Note: We currently don't check for duplicates!
396 * The last config line for each applet will be the
397 * one used since we insert at the head of the list.
398 * I suppose this could be considered a feature. */
399 sct = xzalloc(sizeof(*sct));
400 sct->m_applet = applet_no;
402 sct->m_next = sct_head;
405 /* Get the specified mode. */
407 e = skip_whitespace(e+1);
409 for (i = 0; i < 3; i++) {
410 /* There are 4 chars for each of user/group/other.
411 * "x-xx" instead of "x-" are to make
412 * "idx > 3" check catch invalid chars.
414 static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
415 static const unsigned short mode_mask[] ALIGN2 = {
416 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
417 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
420 const char *q = strchrnul(mode_chars + 4*i, *e);
421 unsigned idx = q - (mode_chars + 4*i);
426 sct->m_mode |= mode_mask[q - mode_chars];
430 /* Now get the user/group info. */
432 s = skip_whitespace(e);
433 /* Default is 0.0, else parse USER.GROUP: */
435 /* We require whitespace between mode and USER.GROUP */
436 if ((s == e) || !(e = strchr(s, '.'))) {
440 *e = ':'; /* get_uidgid needs USER:GROUP syntax */
441 if (get_uidgid(&sct->m_ugid, s, /*allow_numeric:*/ 1) == 0) {
442 errmsg = "unknown user/group";
450 /* Unknown sections are ignored. */
452 /* Encountering configuration lines prior to seeing a
453 * section header is treated as an error. This is how
454 * the old code worked, but it may not be desirable.
455 * We may want to simply ignore such lines in case they
456 * are used in some future version of busybox. */
458 errmsg = "keyword outside section";
466 bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
468 /* Release any allocated memory before returning. */
469 llist_free((llist_t*)sct_head, NULL);
472 static inline void parse_config_file(void)
474 IF_FEATURE_SUID(ruid = getuid();)
476 # endif /* FEATURE_SUID_CONFIG */
479 # if ENABLE_FEATURE_SUID
480 static void check_suid(int applet_no)
482 gid_t rgid; /* real gid */
484 if (ruid == 0) /* set by parse_config_file() */
485 return; /* run by root - no need to check more */
488 # if ENABLE_FEATURE_SUID_CONFIG
489 if (suid_cfg_readable) {
491 struct suid_config_t *sct;
494 for (sct = suid_config; sct; sct = sct->m_next) {
495 if (sct->m_applet == applet_no)
498 goto check_need_suid;
500 /* Is this user allowed to run this applet? */
502 if (sct->m_ugid.uid == ruid)
505 else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
506 /* same group / in group */
508 if (!(m & S_IXOTH)) /* is x bit not set? */
509 bb_error_msg_and_die("you have no permission to run this applet");
511 /* We set effective AND saved ids. If saved-id is not set
512 * like we do below, seteuid(0) can still later succeed! */
514 /* Are we directed to change gid
515 * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
517 if (sct->m_mode & S_ISGID)
518 rgid = sct->m_ugid.gid;
519 /* else: we will set egid = rgid, thus dropping sgid effect */
520 if (setresgid(-1, rgid, rgid))
521 bb_perror_msg_and_die("setresgid");
523 /* Are we directed to change uid
524 * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
527 if (sct->m_mode & S_ISUID)
528 uid = sct->m_ugid.uid;
529 /* else: we will set euid = ruid, thus dropping suid effect */
530 if (setresuid(-1, uid, uid))
531 bb_perror_msg_and_die("setresuid");
535 # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
537 static bool onetime = 0;
541 bb_error_msg("using fallback suid method");
547 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
548 /* Real uid is not 0. If euid isn't 0 too, suid bit
549 * is most probably not set on our executable */
551 bb_error_msg_and_die("must be suid to work properly");
552 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
553 xsetgid(rgid); /* drop all privileges */
556 # if ENABLE_FEATURE_SUID_CONFIG
558 llist_free((llist_t*)suid_config, NULL);
562 # define check_suid(x) ((void)0)
563 # endif /* FEATURE_SUID */
566 # if ENABLE_FEATURE_INSTALLER
567 static const char usr_bin [] ALIGN1 = "/usr/bin/";
568 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
569 static const char *const install_dir[] = {
570 &usr_bin [8], /* "/" */
571 &usr_bin [4], /* "/bin/" */
572 &usr_sbin[4] /* "/sbin/" */
573 # if !ENABLE_INSTALL_NO_USR
579 /* create (sym)links for each applet */
580 static void install_links(const char *busybox, int use_symbolic_links,
581 char *custom_install_dir)
584 * this should be consistent w/ the enum,
585 * busybox.h::bb_install_loc_t, or else... */
586 int (*lf)(const char *, const char *);
592 if (use_symbolic_links)
595 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
596 fpc = concat_path_file(
597 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
599 // debug: bb_error_msg("%slinking %s to busybox",
600 // use_symbolic_links ? "sym" : "", fpc);
601 rc = lf(busybox, fpc);
602 if (rc != 0 && errno != EEXIST) {
603 bb_simple_perror_msg(fpc);
609 # define install_links(x,y,z) ((void)0)
612 /* If we were called as "busybox..." */
613 static int busybox_main(char **argv)
616 /* Called without arguments */
619 unsigned output_width;
622 if (ENABLE_FEATURE_AUTOWIDTH) {
623 /* Obtain the terminal width */
624 get_terminal_width_height(0, &output_width, NULL);
628 full_write2_str(bb_banner); /* reuse const string */
629 full_write2_str(" multi-call binary.\n"); /* reuse */
631 "BusyBox is copyrighted by many authors between 1998-2012.\n"
632 "Licensed under GPLv2. See source distribution for detailed\n"
633 "copyright notices.\n"
635 "Usage: busybox [function [arguments]...]\n"
636 " or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
637 IF_FEATURE_INSTALLER(
638 " or: busybox --install [-s] [DIR]\n"
640 " or: function [arguments]...\n"
642 "\tBusyBox is a multi-call binary that combines many common Unix\n"
643 "\tutilities into a single executable. Most people will create a\n"
644 "\tlink to busybox for each function they wish to use and BusyBox\n"
645 "\twill act like whatever it was invoked as.\n"
647 "Currently defined functions:\n"
651 /* prevent last comma to be in the very last pos */
654 int len2 = strlen(a) + 2;
655 if (col >= (int)output_width - len2) {
656 full_write2_str(",\n");
661 full_write2_str("\t");
663 full_write2_str(", ");
669 full_write2_str("\n\n");
673 if (strncmp(argv[1], "--list", 6) == 0) {
675 const char *a = applet_names;
678 # if ENABLE_FEATURE_INSTALLER
679 if (argv[1][6]) /* --list-full? */
680 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
683 full_write2_str("\n");
690 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
691 int use_symbolic_links;
694 busybox = xmalloc_readlink(bb_busybox_exec_path);
696 /* bb_busybox_exec_path is usually "/proc/self/exe".
697 * In chroot, readlink("/proc/self/exe") usually fails.
698 * In such case, better use argv[0] as symlink target
699 * if it is a full path name.
701 if (argv[0][0] != '/')
702 bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
705 /* busybox --install [-s] [DIR]:
707 * DIR: directory to install links to
709 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
710 install_links(busybox, use_symbolic_links, argv[2]);
714 if (strcmp(argv[1], "--help") == 0) {
715 /* "busybox --help [<applet>]" */
718 /* convert to "<applet> --help" */
722 /* "busybox <applet> arg1 arg2 ..." */
725 /* We support "busybox /a/path/to/applet args..." too. Allows for
726 * "#!/bin/busybox"-style wrappers */
727 applet_name = bb_get_last_path_component_nostrip(argv[0]);
728 run_applet_and_exit(applet_name, argv);
730 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
731 full_write2_str(applet_name);
732 full_write2_str(": applet not found\n");
736 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
743 /* Reinit some shared global data */
744 xfunc_error_retval = EXIT_FAILURE;
746 applet_name = APPLET_NAME(applet_no);
747 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
748 /* Special case. POSIX says "test --help"
749 * should be no different from e.g. "test --foo". */
750 //TODO: just compare applet_no with APPLET_NO_test
751 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0) {
752 /* If you want "foo --help" to return 0: */
753 xfunc_error_retval = 0;
757 if (ENABLE_FEATURE_SUID)
758 check_suid(applet_no);
759 exit(applet_main[applet_no](argc, argv));
762 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
764 int applet = find_applet_by_name(name);
766 run_applet_no_and_exit(applet, argv);
767 if (strncmp(name, "busybox", 7) == 0)
768 exit(busybox_main(argv));
771 #endif /* !defined(SINGLE_APPLET_MAIN) */
775 #if ENABLE_BUILD_LIBBUSYBOX
776 int lbb_main(char **argv)
778 int main(int argc UNUSED_PARAM, char **argv)
781 /* Tweak malloc for reduced memory consumption */
782 #ifdef M_TRIM_THRESHOLD
783 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
784 * to keep before releasing to the OS
785 * Default is way too big: 256k
787 mallopt(M_TRIM_THRESHOLD, 8 * 1024);
789 #ifdef M_MMAP_THRESHOLD
790 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
791 * Default is too big: 256k
793 mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
797 /* NOMMU re-exec trick sets high-order bit in first byte of name */
798 if (argv[0][0] & 0x80) {
804 #if defined(SINGLE_APPLET_MAIN)
805 /* Only one applet is selected in .config */
806 if (argv[1] && strncmp(argv[0], "busybox", 7) == 0) {
807 /* "busybox <applet> <params>" should still work as expected */
810 /* applet_names in this case is just "applet\0\0" */
811 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
812 return SINGLE_APPLET_MAIN(argc, argv);
814 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
816 applet_name = argv[0];
817 if (applet_name[0] == '-')
819 applet_name = bb_basename(applet_name);
821 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
823 run_applet_and_exit(applet_name, argv);
825 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
826 full_write2_str(applet_name);
827 full_write2_str(": applet not found\n");