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. :(
32 /* Try to pull in PAGE_SIZE */
34 # include <sys/user.h>
36 #ifdef __GNU__ /* Hurd */
37 # include <mach/vm_param.h>
41 /* Declare <applet>_main() */
47 /* Include generated applet names, pointers to <applet>_main, etc */
48 #include "applet_tables.h"
49 /* ...and if applet_tables generator says we have only one applet... */
50 #ifdef SINGLE_APPLET_MAIN
51 # undef ENABLE_FEATURE_INDIVIDUAL
52 # define ENABLE_FEATURE_INDIVIDUAL 1
53 # undef IF_FEATURE_INDIVIDUAL
54 # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
58 #include "usage_compressed.h"
60 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
61 static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
63 # define usage_messages 0
66 #if ENABLE_FEATURE_COMPRESS_USAGE
68 static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
69 # 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(UNPACKED_USAGE));
86 read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
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 void FAST_FUNC bb_show_usage(void)
103 if (ENABLE_SHOW_USAGE) {
104 #ifdef SINGLE_APPLET_STR
105 /* Imagine that this applet is "true". Dont suck in printf! */
107 const char *usage_string = p = unpack_usage_messages();
110 full_write2_str("No help available.\n\n");
112 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
114 full_write2_str("\n\n");
116 if (ENABLE_FEATURE_CLEAN_UP)
117 dealloc_usage_messages((char*)usage_string);
120 const char *usage_string = p = unpack_usage_messages();
121 int ap = find_applet_by_name(applet_name);
123 if (ap < 0) /* never happens, paranoia */
126 while (*p++) continue;
129 full_write2_str(bb_banner);
130 full_write2_str(" multi-call binary.\n");
132 full_write2_str("\nNo help available.\n\n");
134 full_write2_str("\nUsage: ");
135 full_write2_str(applet_name);
136 full_write2_str(" ");
138 full_write2_str("\n\n");
140 if (ENABLE_FEATURE_CLEAN_UP)
141 dealloc_usage_messages((char*)usage_string);
148 /* NB: any char pointer will work as well, not necessarily applet_names */
149 static int applet_name_compare(const void *name, const void *v)
151 int i = (const char *)v - applet_names;
152 return strcmp(name, APPLET_NAME(i));
155 int FAST_FUNC find_applet_by_name(const char *name)
158 /* Do a binary search to find the applet entry given the name. */
160 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
163 return p - applet_names;
165 /* A version which does not pull in bsearch */
167 const char *p = applet_names;
168 while (i < NUM_APPLETS) {
169 if (strcmp(name, p) == 0)
179 void lbb_prepare(const char *applet
180 IF_FEATURE_INDIVIDUAL(, char **argv))
181 MAIN_EXTERNALLY_VISIBLE;
182 void lbb_prepare(const char *applet
183 IF_FEATURE_INDIVIDUAL(, char **argv))
186 (*(int **)&bb_errno) = __errno_location();
189 applet_name = applet;
191 /* Set locale for everybody except 'init' */
192 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
193 setlocale(LC_ALL, "");
195 #if ENABLE_FEATURE_INDIVIDUAL
196 /* Redundant for busybox (run_applet_and_exit covers that case)
197 * but needed for "individual applet" mode */
200 && strcmp(argv[1], "--help") == 0
201 && strncmp(applet, "busybox", 7) != 0
203 /* Special case. POSIX says "test --help"
204 * should be no different from e.g. "test --foo". */
205 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
211 /* The code below can well be in applets/applets.c, as it is used only
212 * for busybox binary, not "individual" binaries.
213 * However, keeping it here and linking it into libbusybox.so
214 * (together with remaining tiny applets/applets.o)
215 * makes it possible to avoid --whole-archive at link time.
216 * This makes (shared busybox) + libbusybox smaller.
217 * (--gc-sections would be even better....)
220 const char *applet_name;
226 /* If not built as a single-applet executable... */
227 #if !defined(SINGLE_APPLET_MAIN)
229 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
231 #if ENABLE_FEATURE_SUID_CONFIG
233 /* applets[] is const, so we have to define this "override" structure */
234 static struct BB_suid_config {
239 struct BB_suid_config *m_next;
242 static bool suid_cfg_readable;
244 /* check if u is member of group g */
245 static int ingroup(uid_t u, gid_t g)
247 struct group *grp = getgrgid(g);
252 for (mem = grp->gr_mem; *mem; mem++) {
253 struct passwd *pwd = getpwnam(*mem);
255 if (pwd && (pwd->pw_uid == u))
262 /* This should probably be a libbb routine. In that case,
263 * I'd probably rename it to something like bb_trimmed_slice.
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 /* Don't depend on the tools to combine strings. */
283 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
285 /* We don't supply a value for the nul, so an index adjustment is
286 * necessary below. Also, we use unsigned short here to save some
287 * space even though these are really mode_t values. */
288 static const unsigned short mode_mask[] ALIGN2 = {
289 /* SST sst xxx --- */
290 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
291 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
292 0, S_IXOTH, S_IXOTH, 0 /* other */
295 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
297 static void parse_config_file(void)
299 struct BB_suid_config *sct_head;
300 struct BB_suid_config *sct;
312 assert(!suid_config); /* Should be set to NULL by bss init. */
315 if (ruid == 0) /* run by root - don't need to even read config file */
318 if ((stat(config_file, &st) != 0) /* No config file? */
319 || !S_ISREG(st.st_mode) /* Not a regular file? */
320 || (st.st_uid != 0) /* Not owned by root? */
321 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
322 || !(f = fopen_for_read(config_file)) /* Cannot open? */
327 suid_cfg_readable = 1;
334 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
336 if (ferror(f)) { /* Make sure it wasn't a read error. */
337 parse_error("reading");
340 suid_config = sct_head; /* Success, so set the pointer. */
344 lc++; /* Got a (partial) line. */
346 /* If a line is too long for our buffer, we consider it an error.
347 * The following test does mistreat one corner case though.
348 * If the final line of the file does not end with a newline and
349 * yet exactly fills the buffer, it will be treated as too long
350 * even though there isn't really a problem. But it isn't really
351 * worth adding code to deal with such an unlikely situation, and
352 * we do err on the side of caution. Besides, the line would be
353 * too long if it did end with a newline. */
354 if (!strchr(s, '\n') && !feof(f)) {
355 parse_error("line too long");
358 /* Trim leading and trailing whitespace, ignoring comments, and
359 * check if the resulting string is empty. */
360 s = get_trimmed_slice(s, strchrnul(s, '#'));
365 /* Check for a section header. */
368 /* Unlike the old code, we ignore leading and trailing
369 * whitespace for the section name. We also require that
370 * there are no stray characters after the closing bracket. */
372 if (!e /* Missing right bracket? */
373 || e[1] /* Trailing characters? */
374 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
376 parse_error("section header");
378 /* Right now we only have one section so just check it.
379 * If more sections are added in the future, please don't
380 * resort to cascading ifs with multiple strcasecmp calls.
381 * That kind of bloated code is all too common. A loop
382 * and a string table would be a better choice unless the
383 * number of sections is very small. */
384 if (strcasecmp(s, "SUID") == 0) {
388 section = -1; /* Unknown section so set to skip. */
392 /* Process sections. */
394 if (section == 1) { /* SUID */
395 /* Since we trimmed leading and trailing space above, we're
396 * now looking for strings of the form
397 * <key>[::space::]*=[::space::]*<value>
398 * where both key and value could contain inner whitespace. */
400 /* First get the key (an applet name in our case). */
403 s = get_trimmed_slice(s, e);
405 if (!e || !*s) { /* Missing '=' or empty key. */
406 parse_error("keyword");
409 /* Ok, we have an applet name. Process the rhs if this
410 * applet is currently built in and ignore it otherwise.
411 * Note: this can hide config file bugs which only pop
412 * up when the busybox configuration is changed. */
413 applet_no = find_applet_by_name(s);
414 if (applet_no >= 0) {
415 /* Note: We currently don't check for duplicates!
416 * The last config line for each applet will be the
417 * one used since we insert at the head of the list.
418 * I suppose this could be considered a feature. */
419 sct = xmalloc(sizeof(struct BB_suid_config));
420 sct->m_applet = applet_no;
422 sct->m_next = sct_head;
425 /* Get the specified mode. */
427 e = skip_whitespace(e+1);
429 for (i = 0; i < 3; i++) {
430 /* There are 4 chars + 1 nul for each of user/group/other. */
431 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
434 q = strchrnul(mode_chars + 5*i, *e++);
438 /* Adjust by -i to account for nul. */
439 sct->m_mode |= mode_mask[(q - mode_chars) - i];
442 /* Now get the the user/group info. */
444 s = skip_whitespace(e);
446 /* Note: we require whitespace between the mode and the
447 * user/group info. */
448 if ((s == e) || !(e = strchr(s, '.'))) {
449 parse_error("<uid>.<gid>");
453 /* We can't use get_ug_id here since it would exit()
454 * if a uid or gid was not found. Oh well... */
455 sct->m_uid = bb_strtoul(s, NULL, 10);
457 struct passwd *pwd = getpwnam(s);
461 sct->m_uid = pwd->pw_uid;
464 sct->m_gid = bb_strtoul(e, NULL, 10);
469 parse_error("group");
471 sct->m_gid = grp->gr_gid;
477 /* Unknown sections are ignored. */
479 /* Encountering configuration lines prior to seeing a
480 * section header is treated as an error. This is how
481 * the old code worked, but it may not be desirable.
482 * We may want to simply ignore such lines in case they
483 * are used in some future version of busybox. */
485 parse_error("keyword outside section");
491 fprintf(stderr, "Parse error in %s, line %d: %s\n",
492 config_file, lc, errmsg);
495 /* Release any allocated memory before returning. */
497 sct = sct_head->m_next;
503 static inline void parse_config_file(void)
505 IF_FEATURE_SUID(ruid = getuid();)
507 #endif /* FEATURE_SUID_CONFIG */
510 #if ENABLE_FEATURE_SUID
511 static void check_suid(int applet_no)
513 gid_t rgid; /* real gid */
515 if (ruid == 0) /* set by parse_config_file() */
516 return; /* run by root - no need to check more */
519 #if ENABLE_FEATURE_SUID_CONFIG
520 if (suid_cfg_readable) {
522 struct BB_suid_config *sct;
525 for (sct = suid_config; sct; sct = sct->m_next) {
526 if (sct->m_applet == applet_no)
529 goto check_need_suid;
532 if (sct->m_uid == ruid)
535 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
536 /* same group / in group */
539 if (!(m & S_IXOTH)) /* is x bit not set ? */
540 bb_error_msg_and_die("you have no permission to run this applet!");
542 /* _both_ sgid and group_exec have to be set for setegid */
543 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
545 /* else (no setegid) we will set egid = rgid */
547 /* We set effective AND saved ids. If saved-id is not set
548 * like we do below, seteiud(0) can still later succeed! */
549 if (setresgid(-1, rgid, rgid))
550 bb_perror_msg_and_die("setresgid");
552 /* do we have to set effective uid? */
554 if (sct->m_mode & S_ISUID)
556 /* else (no seteuid) we will set euid = ruid */
558 if (setresuid(-1, uid, uid))
559 bb_perror_msg_and_die("setresuid");
562 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
564 static bool onetime = 0;
568 fprintf(stderr, "Using fallback suid method\n");
574 if (APPLET_SUID(applet_no) == _BB_SUID_REQUIRE) {
575 /* Real uid is not 0. If euid isn't 0 too, suid bit
576 * is most probably not set on our executable */
578 bb_error_msg_and_die("must be suid to work properly");
579 } else if (APPLET_SUID(applet_no) == _BB_SUID_DROP) {
580 xsetgid(rgid); /* drop all privileges */
585 #define check_suid(x) ((void)0)
586 #endif /* FEATURE_SUID */
589 #if ENABLE_FEATURE_INSTALLER
590 static const char usr_bin [] ALIGN1 = "/usr/bin/";
591 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
592 static const char *const install_dir[] = {
593 &usr_bin [8], /* "/" */
594 &usr_bin [4], /* "/bin/" */
595 &usr_sbin[4], /* "/sbin/" */
601 /* create (sym)links for each applet */
602 static void install_links(const char *busybox, int use_symbolic_links,
603 char *custom_install_dir)
606 * this should be consistent w/ the enum,
607 * busybox.h::bb_install_loc_t, or else... */
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)
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"
669 /* prevent last comma to be in the very last pos */
672 int len2 = strlen(a) + 2;
673 if (col >= (int)output_width - len2) {
674 full_write2_str(",\n");
679 full_write2_str("\t");
681 full_write2_str(", ");
687 full_write2_str("\n\n");
691 if (strncmp(argv[1], "--list", 6) == 0) {
693 const char *a = applet_names;
696 #if ENABLE_FEATURE_INSTALLER
697 if (argv[1][6]) /* --list-path? */
698 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
701 full_write2_str("\n");
708 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
709 int use_symbolic_links;
711 busybox = xmalloc_readlink(bb_busybox_exec_path);
713 busybox = bb_busybox_exec_path;
714 /* busybox --install [-s] [DIR]: */
715 /* -s: make symlinks */
716 /* 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))
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 */
788 # define PAGE_SIZE (4*1024) /* guess */
790 #ifdef M_TRIM_THRESHOLD
791 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
792 * to keep before releasing to the OS
793 * Default is way too big: 256k
795 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
797 #ifdef M_MMAP_THRESHOLD
798 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
799 * Default is too big: 256k
801 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
804 #if defined(SINGLE_APPLET_MAIN)
805 /* Only one applet is selected by the user! */
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));
813 /* NOMMU re-exec trick sets high-order bit in first byte of name */
814 if (argv[0][0] & 0x80) {
819 applet_name = argv[0];
820 if (applet_name[0] == '-')
822 applet_name = bb_basename(applet_name);
824 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
826 run_applet_and_exit(applet_name, argv);
828 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
829 full_write2_str(applet_name);
830 full_write2_str(": applet not found\n");