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. :(
33 #include <sys/user.h> /* PAGE_SIZE */
36 /* Declare <applet>_main() */
41 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
42 /* Define usage_messages[] */
43 static const char usage_messages[] ALIGN1 = ""
50 #define usage_messages 0
51 #endif /* SHOW_USAGE */
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__
65 #if ENABLE_FEATURE_COMPRESS_USAGE
67 #include "usage_compressed.h"
68 #include "unarchive.h"
70 static const char *unpack_usage_messages(void)
78 /* inbuf: */ (void *)packed_usage,
79 /* len: */ sizeof(packed_usage));
80 /* read_bunzip can longjmp to start_bunzip, and ultimately
81 * end up here with i != 0 on read data errors! Not trivial */
83 /* Cannot use xmalloc: will leak bd in NOFORK case! */
84 outbuf = malloc_or_warn(SIZEOF_usage_messages);
86 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
91 #define dealloc_usage_messages(s) free(s)
95 #define unpack_usage_messages() usage_messages
96 #define dealloc_usage_messages(s) ((void)(s))
98 #endif /* FEATURE_COMPRESS_USAGE */
101 static void full_write2_str(const char *str)
103 xwrite_str(STDERR_FILENO, str);
106 void FAST_FUNC bb_show_usage(void)
108 if (ENABLE_SHOW_USAGE) {
109 #ifdef SINGLE_APPLET_STR
110 /* Imagine that this applet is "true". Dont suck in printf! */
112 const char *usage_string = p = unpack_usage_messages();
115 full_write2_str("No help available.\n\n");
117 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
119 full_write2_str("\n\n");
121 if (ENABLE_FEATURE_CLEAN_UP)
122 dealloc_usage_messages((char*)usage_string);
125 const char *usage_string = p = unpack_usage_messages();
126 int ap = find_applet_by_name(applet_name);
128 if (ap < 0) /* never happens, paranoia */
131 while (*p++) continue;
134 full_write2_str(bb_banner);
135 full_write2_str(" multi-call binary.\n");
137 full_write2_str("\nNo help available.\n\n");
139 full_write2_str("\nUsage: ");
140 full_write2_str(applet_name);
141 full_write2_str(" ");
143 full_write2_str("\n\n");
145 if (ENABLE_FEATURE_CLEAN_UP)
146 dealloc_usage_messages((char*)usage_string);
153 /* NB: any char pointer will work as well, not necessarily applet_names */
154 static int applet_name_compare(const void *name, const void *v)
156 int i = (const char *)v - applet_names;
157 return strcmp(name, APPLET_NAME(i));
160 int FAST_FUNC find_applet_by_name(const char *name)
163 /* Do a binary search to find the applet entry given the name. */
165 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
168 return p - applet_names;
170 /* A version which does not pull in bsearch */
172 const char *p = applet_names;
173 while (i < NUM_APPLETS) {
174 if (strcmp(name, p) == 0)
184 void lbb_prepare(const char *applet
185 IF_FEATURE_INDIVIDUAL(, char **argv))
186 MAIN_EXTERNALLY_VISIBLE;
187 void lbb_prepare(const char *applet
188 IF_FEATURE_INDIVIDUAL(, char **argv))
191 (*(int **)&bb_errno) = __errno_location();
194 applet_name = applet;
196 /* Set locale for everybody except 'init' */
197 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
198 setlocale(LC_ALL, "");
200 #if ENABLE_FEATURE_INDIVIDUAL
201 /* Redundant for busybox (run_applet_and_exit covers that case)
202 * but needed for "individual applet" mode */
203 if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
204 /* Special case. POSIX says "test --help"
205 * should be no different from e.g. "test --foo". */
206 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
212 /* The code below can well be in applets/applets.c, as it is used only
213 * for busybox binary, not "individual" binaries.
214 * However, keeping it here and linking it into libbusybox.so
215 * (together with remaining tiny applets/applets.o)
216 * makes it possible to avoid --whole-archive at link time.
217 * This makes (shared busybox) + libbusybox smaller.
218 * (--gc-sections would be even better....)
221 const char *applet_name;
227 /* If not built as a single-applet executable... */
228 #if !defined(SINGLE_APPLET_MAIN)
230 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
232 #if ENABLE_FEATURE_SUID_CONFIG
234 /* applets[] is const, so we have to define this "override" structure */
235 static struct BB_suid_config {
240 struct BB_suid_config *m_next;
243 static bool suid_cfg_readable;
245 /* check if u is member of group g */
246 static int ingroup(uid_t u, gid_t g)
248 struct group *grp = getgrgid(g);
253 for (mem = grp->gr_mem; *mem; mem++) {
254 struct passwd *pwd = getpwnam(*mem);
256 if (pwd && (pwd->pw_uid == u))
263 /* This should probably be a libbb routine. In that case,
264 * I'd probably rename it to something like bb_trimmed_slice.
266 static char *get_trimmed_slice(char *s, char *e)
268 /* First, consider the value at e to be nul and back up until we
269 * reach a non-space char. Set the char after that (possibly at
270 * the original e) to nul. */
278 /* Next, advance past all leading space and return a ptr to the
279 * first non-space char; possibly the terminating nul. */
280 return skip_whitespace(s);
283 /* Don't depend on the tools to combine strings. */
284 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
286 /* We don't supply a value for the nul, so an index adjustment is
287 * necessary below. Also, we use unsigned short here to save some
288 * space even though these are really mode_t values. */
289 static const unsigned short mode_mask[] ALIGN2 = {
290 /* SST sst xxx --- */
291 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
292 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
293 0, S_IXOTH, S_IXOTH, 0 /* other */
296 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
298 static void parse_config_file(void)
300 struct BB_suid_config *sct_head;
301 struct BB_suid_config *sct;
313 assert(!suid_config); /* Should be set to NULL by bss init. */
316 if (ruid == 0) /* run by root - don't need to even read config file */
319 if ((stat(config_file, &st) != 0) /* No config file? */
320 || !S_ISREG(st.st_mode) /* Not a regular file? */
321 || (st.st_uid != 0) /* Not owned by root? */
322 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
323 || !(f = fopen_for_read(config_file)) /* Cannot open? */
328 suid_cfg_readable = 1;
335 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
337 if (ferror(f)) { /* Make sure it wasn't a read error. */
338 parse_error("reading");
341 suid_config = sct_head; /* Success, so set the pointer. */
345 lc++; /* Got a (partial) line. */
347 /* If a line is too long for our buffer, we consider it an error.
348 * The following test does mistreat one corner case though.
349 * If the final line of the file does not end with a newline and
350 * yet exactly fills the buffer, it will be treated as too long
351 * even though there isn't really a problem. But it isn't really
352 * worth adding code to deal with such an unlikely situation, and
353 * we do err on the side of caution. Besides, the line would be
354 * too long if it did end with a newline. */
355 if (!strchr(s, '\n') && !feof(f)) {
356 parse_error("line too long");
359 /* Trim leading and trailing whitespace, ignoring comments, and
360 * check if the resulting string is empty. */
361 s = get_trimmed_slice(s, strchrnul(s, '#'));
366 /* Check for a section header. */
369 /* Unlike the old code, we ignore leading and trailing
370 * whitespace for the section name. We also require that
371 * there are no stray characters after the closing bracket. */
373 if (!e /* Missing right bracket? */
374 || e[1] /* Trailing characters? */
375 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
377 parse_error("section header");
379 /* Right now we only have one section so just check it.
380 * If more sections are added in the future, please don't
381 * resort to cascading ifs with multiple strcasecmp calls.
382 * That kind of bloated code is all too common. A loop
383 * and a string table would be a better choice unless the
384 * number of sections is very small. */
385 if (strcasecmp(s, "SUID") == 0) {
389 section = -1; /* Unknown section so set to skip. */
393 /* Process sections. */
395 if (section == 1) { /* SUID */
396 /* Since we trimmed leading and trailing space above, we're
397 * now looking for strings of the form
398 * <key>[::space::]*=[::space::]*<value>
399 * where both key and value could contain inner whitespace. */
401 /* First get the key (an applet name in our case). */
404 s = get_trimmed_slice(s, e);
406 if (!e || !*s) { /* Missing '=' or empty key. */
407 parse_error("keyword");
410 /* Ok, we have an applet name. Process the rhs if this
411 * applet is currently built in and ignore it otherwise.
412 * Note: this can hide config file bugs which only pop
413 * up when the busybox configuration is changed. */
414 applet_no = find_applet_by_name(s);
415 if (applet_no >= 0) {
416 /* Note: We currently don't check for duplicates!
417 * The last config line for each applet will be the
418 * one used since we insert at the head of the list.
419 * I suppose this could be considered a feature. */
420 sct = xmalloc(sizeof(struct BB_suid_config));
421 sct->m_applet = applet_no;
423 sct->m_next = sct_head;
426 /* Get the specified mode. */
428 e = skip_whitespace(e+1);
430 for (i = 0; i < 3; i++) {
431 /* There are 4 chars + 1 nul for each of user/group/other. */
432 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
435 q = strchrnul(mode_chars + 5*i, *e++);
439 /* Adjust by -i to account for nul. */
440 sct->m_mode |= mode_mask[(q - mode_chars) - i];
443 /* Now get the the user/group info. */
445 s = skip_whitespace(e);
447 /* Note: we require whitespace between the mode and the
448 * user/group info. */
449 if ((s == e) || !(e = strchr(s, '.'))) {
450 parse_error("<uid>.<gid>");
454 /* We can't use get_ug_id here since it would exit()
455 * if a uid or gid was not found. Oh well... */
456 sct->m_uid = bb_strtoul(s, NULL, 10);
458 struct passwd *pwd = getpwnam(s);
462 sct->m_uid = pwd->pw_uid;
465 sct->m_gid = bb_strtoul(e, NULL, 10);
470 parse_error("group");
472 sct->m_gid = grp->gr_gid;
478 /* Unknown sections are ignored. */
480 /* Encountering configuration lines prior to seeing a
481 * section header is treated as an error. This is how
482 * the old code worked, but it may not be desirable.
483 * We may want to simply ignore such lines in case they
484 * are used in some future version of busybox. */
486 parse_error("keyword outside section");
492 fprintf(stderr, "Parse error in %s, line %d: %s\n",
493 config_file, lc, errmsg);
496 /* Release any allocated memory before returning. */
498 sct = sct_head->m_next;
504 static inline void parse_config_file(void)
506 IF_FEATURE_SUID(ruid = getuid();)
508 #endif /* FEATURE_SUID_CONFIG */
511 #if ENABLE_FEATURE_SUID
512 static void check_suid(int applet_no)
514 gid_t rgid; /* real gid */
516 if (ruid == 0) /* set by parse_config_file() */
517 return; /* run by root - no need to check more */
520 #if ENABLE_FEATURE_SUID_CONFIG
521 if (suid_cfg_readable) {
523 struct BB_suid_config *sct;
526 for (sct = suid_config; sct; sct = sct->m_next) {
527 if (sct->m_applet == applet_no)
530 goto check_need_suid;
533 if (sct->m_uid == ruid)
536 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
537 /* same group / in group */
540 if (!(m & S_IXOTH)) /* is x bit not set ? */
541 bb_error_msg_and_die("you have no permission to run this applet!");
543 /* _both_ sgid and group_exec have to be set for setegid */
544 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
546 /* else (no setegid) we will set egid = rgid */
548 /* We set effective AND saved ids. If saved-id is not set
549 * like we do below, seteiud(0) can still later succeed! */
550 if (setresgid(-1, rgid, rgid))
551 bb_perror_msg_and_die("setresgid");
553 /* do we have to set effective uid? */
555 if (sct->m_mode & S_ISUID)
557 /* else (no seteuid) we will set euid = ruid */
559 if (setresuid(-1, uid, uid))
560 bb_perror_msg_and_die("setresuid");
563 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
565 static bool onetime = 0;
569 fprintf(stderr, "Using fallback suid method\n");
575 if (APPLET_SUID(applet_no) == _BB_SUID_REQUIRE) {
576 /* Real uid is not 0. If euid isn't 0 too, suid bit
577 * is most probably not set on our executable */
579 bb_error_msg_and_die("must be suid to work properly");
580 } else if (APPLET_SUID(applet_no) == _BB_SUID_DROP) {
581 xsetgid(rgid); /* drop all privileges */
586 #define check_suid(x) ((void)0)
587 #endif /* FEATURE_SUID */
590 #if ENABLE_FEATURE_INSTALLER
591 /* create (sym)links for each applet */
592 static void install_links(const char *busybox, int use_symbolic_links,
593 char *custom_install_dir)
596 * this should be consistent w/ the enum,
597 * busybox.h::bb_install_loc_t, or else... */
598 static const char usr_bin [] ALIGN1 = "/usr/bin";
599 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
600 static const char *const install_dir[] = {
601 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
602 &usr_bin [4], /* "/bin" */
603 &usr_sbin[4], /* "/sbin" */
608 int (*lf)(const char *, const char *);
614 if (use_symbolic_links)
617 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
618 fpc = concat_path_file(
619 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
621 // debug: bb_error_msg("%slinking %s to busybox",
622 // use_symbolic_links ? "sym" : "", fpc);
623 rc = lf(busybox, fpc);
624 if (rc != 0 && errno != EEXIST) {
625 bb_simple_perror_msg(fpc);
631 #define install_links(x,y,z) ((void)0)
632 #endif /* FEATURE_INSTALLER */
634 /* If we were called as "busybox..." */
635 static int busybox_main(char **argv)
638 /* Called without arguments */
641 unsigned output_width;
644 if (ENABLE_FEATURE_AUTOWIDTH) {
645 /* Obtain the terminal width */
646 get_terminal_width_height(0, &output_width, NULL);
650 full_write2_str(bb_banner); /* reuse const string */
651 full_write2_str(" multi-call binary.\n"); /* reuse */
653 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
654 "and others. Licensed under GPLv2.\n"
655 "See source distribution for full notice.\n"
657 "Usage: busybox [function] [arguments]...\n"
658 " or: function [arguments]...\n"
660 "\tBusyBox is a multi-call binary that combines many common Unix\n"
661 "\tutilities into a single executable. Most people will create a\n"
662 "\tlink to busybox for each function they wish to use and BusyBox\n"
663 "\twill act like whatever it was invoked as.\n"
665 "Currently defined functions:\n");
668 /* prevent last comma to be in the very last pos */
671 int len2 = strlen(a) + 2;
672 if (col >= (int)output_width - len2) {
673 full_write2_str(",\n");
678 full_write2_str("\t");
680 full_write2_str(", ");
686 full_write2_str("\n\n");
690 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
691 int use_symbolic_links;
693 busybox = xmalloc_readlink(bb_busybox_exec_path);
695 busybox = bb_busybox_exec_path;
696 /* busybox --install [-s] [DIR]: */
697 /* -s: make symlinks */
698 /* DIR: directory to install links to */
699 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
700 install_links(busybox, use_symbolic_links, argv[2]);
704 if (strcmp(argv[1], "--help") == 0) {
705 /* "busybox --help [<applet>]" */
708 /* convert to "<applet> --help" */
712 /* "busybox <applet> arg1 arg2 ..." */
715 /* We support "busybox /a/path/to/applet args..." too. Allows for
716 * "#!/bin/busybox"-style wrappers */
717 applet_name = bb_get_last_path_component_nostrip(argv[0]);
718 run_applet_and_exit(applet_name, argv);
720 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
721 full_write2_str(applet_name);
722 full_write2_str(": applet not found\n");
726 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
733 /* Reinit some shared global data */
734 xfunc_error_retval = EXIT_FAILURE;
736 applet_name = APPLET_NAME(applet_no);
737 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
738 /* Special case. POSIX says "test --help"
739 * should be no different from e.g. "test --foo". */
740 //TODO: just compare applet_no with APPLET_NO_test
741 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
744 if (ENABLE_FEATURE_SUID)
745 check_suid(applet_no);
746 exit(applet_main[applet_no](argc, argv));
749 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
751 int applet = find_applet_by_name(name);
753 run_applet_no_and_exit(applet, argv);
754 if (!strncmp(name, "busybox", 7))
755 exit(busybox_main(argv));
758 #endif /* !defined(SINGLE_APPLET_MAIN) */
762 #if ENABLE_BUILD_LIBBUSYBOX
763 int lbb_main(char **argv)
765 int main(int argc UNUSED_PARAM, char **argv)
768 /* Tweak malloc for reduced memory consumption */
770 # define PAGE_SIZE (4*1024) /* guess */
772 #ifdef M_TRIM_THRESHOLD
773 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
774 * to keep before releasing to the OS
775 * Default is way too big: 256k
777 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
779 #ifdef M_MMAP_THRESHOLD
780 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
781 * Default is too big: 256k
783 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
786 #if defined(SINGLE_APPLET_MAIN)
787 /* Only one applet is selected by the user! */
788 /* applet_names in this case is just "applet\0\0" */
789 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
790 return SINGLE_APPLET_MAIN(argc, argv);
792 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
795 /* NOMMU re-exec trick sets high-order bit in first byte of name */
796 if (argv[0][0] & 0x80) {
801 applet_name = argv[0];
802 if (applet_name[0] == '-')
804 applet_name = bb_basename(applet_name);
806 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
808 run_applet_and_exit(applet_name, argv);
810 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
811 full_write2_str(applet_name);
812 full_write2_str(": applet not found\n");