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.
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. :(
34 /* Declare <applet>_main() */
39 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
40 /* Define usage_messages[] */
41 static const char usage_messages[] ALIGN1 = ""
48 #define usage_messages 0
49 #endif /* SHOW_USAGE */
52 /* Include generated applet names, pointers to <applet>_main, etc */
53 #include "applet_tables.h"
54 /* ...and if applet_tables generator says we have only one applet... */
55 #ifdef SINGLE_APPLET_MAIN
56 #undef ENABLE_FEATURE_INDIVIDUAL
57 #define ENABLE_FEATURE_INDIVIDUAL 1
58 #undef IF_FEATURE_INDIVIDUAL
59 #define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
63 #if ENABLE_FEATURE_COMPRESS_USAGE
65 #include "usage_compressed.h"
66 #include "unarchive.h"
68 static const char *unpack_usage_messages(void)
76 /* inbuf: */ (void *)packed_usage,
77 /* len: */ sizeof(packed_usage));
78 /* read_bunzip can longjmp to start_bunzip, and ultimately
79 * end up here with i != 0 on read data errors! Not trivial */
81 /* Cannot use xmalloc: will leak bd in NOFORK case! */
82 outbuf = malloc_or_warn(SIZEOF_usage_messages);
84 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
89 #define dealloc_usage_messages(s) free(s)
93 #define unpack_usage_messages() usage_messages
94 #define dealloc_usage_messages(s) ((void)(s))
96 #endif /* FEATURE_COMPRESS_USAGE */
99 static void full_write2_str(const char *str)
101 xwrite_str(STDERR_FILENO, str);
104 void FAST_FUNC bb_show_usage(void)
106 if (ENABLE_SHOW_USAGE) {
107 #ifdef SINGLE_APPLET_STR
108 /* Imagine that this applet is "true". Dont suck in printf! */
110 const char *usage_string = p = unpack_usage_messages();
113 full_write2_str("No help available.\n\n");
115 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
117 full_write2_str("\n\n");
119 dealloc_usage_messages((char*)usage_string);
122 const char *usage_string = p = unpack_usage_messages();
123 int ap = find_applet_by_name(applet_name);
125 if (ap < 0) /* never happens, paranoia */
128 while (*p++) continue;
131 full_write2_str(bb_banner);
132 full_write2_str(" multi-call binary\n");
134 full_write2_str("\nNo help available.\n\n");
136 full_write2_str("\nUsage: ");
137 full_write2_str(applet_name);
138 full_write2_str(" ");
140 full_write2_str("\n\n");
142 dealloc_usage_messages((char*)usage_string);
149 /* NB: any char pointer will work as well, not necessarily applet_names */
150 static int applet_name_compare(const void *name, const void *v)
152 int i = (const char *)v - applet_names;
153 return strcmp(name, APPLET_NAME(i));
156 int FAST_FUNC find_applet_by_name(const char *name)
159 /* Do a binary search to find the applet entry given the name. */
161 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
164 return p - applet_names;
166 /* A version which does not pull in bsearch */
168 const char *p = applet_names;
169 while (i < NUM_APPLETS) {
170 if (strcmp(name, p) == 0)
180 void lbb_prepare(const char *applet
181 IF_FEATURE_INDIVIDUAL(, char **argv))
182 MAIN_EXTERNALLY_VISIBLE;
183 void lbb_prepare(const char *applet
184 IF_FEATURE_INDIVIDUAL(, char **argv))
187 (*(int **)&bb_errno) = __errno_location();
190 applet_name = applet;
192 /* Set locale for everybody except 'init' */
193 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
194 setlocale(LC_ALL, "");
196 #if ENABLE_FEATURE_INDIVIDUAL
197 /* Redundant for busybox (run_applet_and_exit covers that case)
198 * but needed for "individual applet" mode */
199 if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
200 /* Special case. POSIX says "test --help"
201 * should be no different from e.g. "test --foo". */
202 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
208 /* The code below can well be in applets/applets.c, as it is used only
209 * for busybox binary, not "individual" binaries.
210 * However, keeping it here and linking it into libbusybox.so
211 * (together with remaining tiny applets/applets.o)
212 * makes it possible to avoid --whole-archive at link time.
213 * This makes (shared busybox) + libbusybox smaller.
214 * (--gc-sections would be even better....)
217 const char *applet_name;
223 /* If not built as a single-applet executable... */
224 #if !defined(SINGLE_APPLET_MAIN)
226 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
228 #if ENABLE_FEATURE_SUID_CONFIG
230 /* applets[] is const, so we have to define this "override" structure */
231 static struct BB_suid_config {
236 struct BB_suid_config *m_next;
239 static bool suid_cfg_readable;
241 /* check if u is member of group g */
242 static int ingroup(uid_t u, gid_t g)
244 struct group *grp = getgrgid(g);
249 for (mem = grp->gr_mem; *mem; mem++) {
250 struct passwd *pwd = getpwnam(*mem);
252 if (pwd && (pwd->pw_uid == u))
259 /* This should probably be a libbb routine. In that case,
260 * I'd probably rename it to something like bb_trimmed_slice.
262 static char *get_trimmed_slice(char *s, char *e)
264 /* First, consider the value at e to be nul and back up until we
265 * reach a non-space char. Set the char after that (possibly at
266 * the original e) to nul. */
274 /* Next, advance past all leading space and return a ptr to the
275 * first non-space char; possibly the terminating nul. */
276 return skip_whitespace(s);
279 /* Don't depend on the tools to combine strings. */
280 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
282 /* We don't supply a value for the nul, so an index adjustment is
283 * necessary below. Also, we use unsigned short here to save some
284 * space even though these are really mode_t values. */
285 static const unsigned short mode_mask[] ALIGN2 = {
286 /* SST sst xxx --- */
287 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
288 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
289 0, S_IXOTH, S_IXOTH, 0 /* other */
292 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
294 static void parse_config_file(void)
296 struct BB_suid_config *sct_head;
297 struct BB_suid_config *sct;
309 assert(!suid_config); /* Should be set to NULL by bss init. */
312 if (ruid == 0) /* run by root - don't need to even read config file */
315 if ((stat(config_file, &st) != 0) /* No config file? */
316 || !S_ISREG(st.st_mode) /* Not a regular file? */
317 || (st.st_uid != 0) /* Not owned by root? */
318 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
319 || !(f = fopen_for_read(config_file)) /* Cannot open? */
324 suid_cfg_readable = 1;
331 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
333 if (ferror(f)) { /* Make sure it wasn't a read error. */
334 parse_error("reading");
337 suid_config = sct_head; /* Success, so set the pointer. */
341 lc++; /* Got a (partial) line. */
343 /* If a line is too long for our buffer, we consider it an error.
344 * The following test does mistreat one corner case though.
345 * If the final line of the file does not end with a newline and
346 * yet exactly fills the buffer, it will be treated as too long
347 * even though there isn't really a problem. But it isn't really
348 * worth adding code to deal with such an unlikely situation, and
349 * we do err on the side of caution. Besides, the line would be
350 * too long if it did end with a newline. */
351 if (!strchr(s, '\n') && !feof(f)) {
352 parse_error("line too long");
355 /* Trim leading and trailing whitespace, ignoring comments, and
356 * check if the resulting string is empty. */
357 s = get_trimmed_slice(s, strchrnul(s, '#'));
362 /* Check for a section header. */
365 /* Unlike the old code, we ignore leading and trailing
366 * whitespace for the section name. We also require that
367 * there are no stray characters after the closing bracket. */
369 if (!e /* Missing right bracket? */
370 || e[1] /* Trailing characters? */
371 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
373 parse_error("section header");
375 /* Right now we only have one section so just check it.
376 * If more sections are added in the future, please don't
377 * resort to cascading ifs with multiple strcasecmp calls.
378 * That kind of bloated code is all too common. A loop
379 * and a string table would be a better choice unless the
380 * number of sections is very small. */
381 if (strcasecmp(s, "SUID") == 0) {
385 section = -1; /* Unknown section so set to skip. */
389 /* Process sections. */
391 if (section == 1) { /* SUID */
392 /* Since we trimmed leading and trailing space above, we're
393 * now looking for strings of the form
394 * <key>[::space::]*=[::space::]*<value>
395 * where both key and value could contain inner whitespace. */
397 /* First get the key (an applet name in our case). */
400 s = get_trimmed_slice(s, e);
402 if (!e || !*s) { /* Missing '=' or empty key. */
403 parse_error("keyword");
406 /* Ok, we have an applet name. Process the rhs if this
407 * applet is currently built in and ignore it otherwise.
408 * Note: this can hide config file bugs which only pop
409 * up when the busybox configuration is changed. */
410 applet_no = find_applet_by_name(s);
411 if (applet_no >= 0) {
412 /* Note: We currently don't check for duplicates!
413 * The last config line for each applet will be the
414 * one used since we insert at the head of the list.
415 * I suppose this could be considered a feature. */
416 sct = xmalloc(sizeof(struct BB_suid_config));
417 sct->m_applet = applet_no;
419 sct->m_next = sct_head;
422 /* Get the specified mode. */
424 e = skip_whitespace(e+1);
426 for (i = 0; i < 3; i++) {
427 /* There are 4 chars + 1 nul for each of user/group/other. */
428 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
431 q = strchrnul(mode_chars + 5*i, *e++);
435 /* Adjust by -i to account for nul. */
436 sct->m_mode |= mode_mask[(q - mode_chars) - i];
439 /* Now get the the user/group info. */
441 s = skip_whitespace(e);
443 /* Note: we require whitespace between the mode and the
444 * user/group info. */
445 if ((s == e) || !(e = strchr(s, '.'))) {
446 parse_error("<uid>.<gid>");
450 /* We can't use get_ug_id here since it would exit()
451 * if a uid or gid was not found. Oh well... */
452 sct->m_uid = bb_strtoul(s, NULL, 10);
454 struct passwd *pwd = getpwnam(s);
458 sct->m_uid = pwd->pw_uid;
461 sct->m_gid = bb_strtoul(e, NULL, 10);
466 parse_error("group");
468 sct->m_gid = grp->gr_gid;
474 /* Unknown sections are ignored. */
476 /* Encountering configuration lines prior to seeing a
477 * section header is treated as an error. This is how
478 * the old code worked, but it may not be desirable.
479 * We may want to simply ignore such lines in case they
480 * are used in some future version of busybox. */
482 parse_error("keyword outside section");
488 fprintf(stderr, "Parse error in %s, line %d: %s\n",
489 config_file, lc, errmsg);
492 /* Release any allocated memory before returning. */
494 sct = sct_head->m_next;
500 static inline void parse_config_file(void)
502 IF_FEATURE_SUID(ruid = getuid();)
504 #endif /* FEATURE_SUID_CONFIG */
507 #if ENABLE_FEATURE_SUID
508 static void check_suid(int applet_no)
510 gid_t rgid; /* real gid */
512 if (ruid == 0) /* set by parse_config_file() */
513 return; /* run by root - no need to check more */
516 #if ENABLE_FEATURE_SUID_CONFIG
517 if (suid_cfg_readable) {
519 struct BB_suid_config *sct;
522 for (sct = suid_config; sct; sct = sct->m_next) {
523 if (sct->m_applet == applet_no)
526 goto check_need_suid;
529 if (sct->m_uid == ruid)
532 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
533 /* same group / in group */
536 if (!(m & S_IXOTH)) /* is x bit not set ? */
537 bb_error_msg_and_die("you have no permission to run this applet!");
539 /* _both_ sgid and group_exec have to be set for setegid */
540 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
542 /* else (no setegid) we will set egid = rgid */
544 /* We set effective AND saved ids. If saved-id is not set
545 * like we do below, seteiud(0) can still later succeed! */
546 if (setresgid(-1, rgid, rgid))
547 bb_perror_msg_and_die("setresgid");
549 /* do we have to set effective uid? */
551 if (sct->m_mode & S_ISUID)
553 /* else (no seteuid) we will set euid = ruid */
555 if (setresuid(-1, uid, uid))
556 bb_perror_msg_and_die("setresuid");
559 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
561 static bool onetime = 0;
565 fprintf(stderr, "Using fallback suid method\n");
571 if (APPLET_SUID(applet_no) == _BB_SUID_REQUIRE) {
572 /* Real uid is not 0. If euid isn't 0 too, suid bit
573 * is most probably not set on our executable */
575 bb_error_msg_and_die("must be suid to work properly");
576 } else if (APPLET_SUID(applet_no) == _BB_SUID_DROP) {
577 xsetgid(rgid); /* drop all privileges */
582 #define check_suid(x) ((void)0)
583 #endif /* FEATURE_SUID */
586 #if ENABLE_FEATURE_INSTALLER
587 /* create (sym)links for each applet */
588 static void install_links(const char *busybox, int use_symbolic_links,
589 char *custom_install_dir)
592 * this should be consistent w/ the enum,
593 * busybox.h::bb_install_loc_t, or else... */
594 static const char usr_bin [] ALIGN1 = "/usr/bin";
595 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
596 static const char *const install_dir[] = {
597 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
598 &usr_bin [4], /* "/bin" */
599 &usr_sbin[4], /* "/sbin" */
604 int (*lf)(const char *, const char *);
610 if (use_symbolic_links)
613 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
614 fpc = concat_path_file(
615 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
617 // debug: bb_error_msg("%slinking %s to busybox",
618 // use_symbolic_links ? "sym" : "", fpc);
619 rc = lf(busybox, fpc);
620 if (rc != 0 && errno != EEXIST) {
621 bb_simple_perror_msg(fpc);
627 #define install_links(x,y,z) ((void)0)
628 #endif /* FEATURE_INSTALLER */
630 /* If we were called as "busybox..." */
631 static int busybox_main(char **argv)
634 /* Called without arguments */
637 unsigned output_width;
640 if (ENABLE_FEATURE_AUTOWIDTH) {
641 /* Obtain the terminal width */
642 get_terminal_width_height(0, &output_width, NULL);
646 full_write2_str(bb_banner); /* reuse const string... */
647 full_write2_str(" multi-call binary\n"
648 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
649 "and others. Licensed under GPLv2.\n"
650 "See source distribution for full notice.\n"
652 "Usage: busybox [function] [arguments]...\n"
653 " or: function [arguments]...\n"
655 "\tBusyBox is a multi-call binary that combines many common Unix\n"
656 "\tutilities into a single executable. Most people will create a\n"
657 "\tlink to busybox for each function they wish to use and BusyBox\n"
658 "\twill act like whatever it was invoked as!\n"
660 "Currently defined functions:\n");
663 /* prevent last comma to be in the very last pos */
666 int len2 = strlen(a) + 2;
667 if (col >= (int)output_width - len2) {
668 full_write2_str(",\n");
673 full_write2_str("\t");
675 full_write2_str(", ");
681 full_write2_str("\n\n");
685 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
686 int use_symbolic_links;
688 busybox = xmalloc_readlink(bb_busybox_exec_path);
690 busybox = bb_busybox_exec_path;
691 /* busybox --install [-s] [DIR]: */
692 /* -s: make symlinks */
693 /* DIR: directory to install links to */
694 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
695 install_links(busybox, use_symbolic_links, argv[2]);
699 if (strcmp(argv[1], "--help") == 0) {
700 /* "busybox --help [<applet>]" */
703 /* convert to "<applet> --help" */
707 /* "busybox <applet> arg1 arg2 ..." */
710 /* We support "busybox /a/path/to/applet args..." too. Allows for
711 * "#!/bin/busybox"-style wrappers */
712 applet_name = bb_get_last_path_component_nostrip(argv[0]);
713 run_applet_and_exit(applet_name, argv);
715 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
716 full_write2_str(applet_name);
717 full_write2_str(": applet not found\n");
721 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
728 /* Reinit some shared global data */
729 xfunc_error_retval = EXIT_FAILURE;
731 applet_name = APPLET_NAME(applet_no);
732 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
733 /* Special case. POSIX says "test --help"
734 * should be no different from e.g. "test --foo". */
735 //TODO: just compare applet_no with APPLET_NO_test
736 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
739 if (ENABLE_FEATURE_SUID)
740 check_suid(applet_no);
741 exit(applet_main[applet_no](argc, argv));
744 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
746 int applet = find_applet_by_name(name);
748 run_applet_no_and_exit(applet, argv);
749 if (!strncmp(name, "busybox", 7))
750 exit(busybox_main(argv));
753 #endif /* !defined(SINGLE_APPLET_MAIN) */
757 #if ENABLE_BUILD_LIBBUSYBOX
758 int lbb_main(char **argv)
760 int main(int argc UNUSED_PARAM, char **argv)
763 #if defined(SINGLE_APPLET_MAIN)
764 /* Only one applet is selected by the user! */
765 /* applet_names in this case is just "applet\0\0" */
766 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
767 return SINGLE_APPLET_MAIN(argc, argv);
769 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
772 /* NOMMU re-exec trick sets high-order bit in first byte of name */
773 if (argv[0][0] & 0x80) {
778 applet_name = argv[0];
779 if (applet_name[0] == '-')
781 applet_name = bb_basename(applet_name);
783 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
785 run_applet_and_exit(applet_name, argv);
787 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
788 full_write2_str(applet_name);
789 full_write2_str(": applet not found\n");