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. :(
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 */
198 if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 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 /* applets[] is const, so we have to define this "override" structure */
230 static struct BB_suid_config {
235 struct BB_suid_config *m_next;
238 static bool suid_cfg_readable;
240 /* check if u is member of group g */
241 static int ingroup(uid_t u, gid_t g)
243 struct group *grp = getgrgid(g);
248 for (mem = grp->gr_mem; *mem; mem++) {
249 struct passwd *pwd = getpwnam(*mem);
251 if (pwd && (pwd->pw_uid == u))
258 /* This should probably be a libbb routine. In that case,
259 * I'd probably rename it to something like bb_trimmed_slice.
261 static char *get_trimmed_slice(char *s, char *e)
263 /* First, consider the value at e to be nul and back up until we
264 * reach a non-space char. Set the char after that (possibly at
265 * the original e) to nul. */
273 /* Next, advance past all leading space and return a ptr to the
274 * first non-space char; possibly the terminating nul. */
275 return skip_whitespace(s);
278 /* Don't depend on the tools to combine strings. */
279 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
281 /* We don't supply a value for the nul, so an index adjustment is
282 * necessary below. Also, we use unsigned short here to save some
283 * space even though these are really mode_t values. */
284 static const unsigned short mode_mask[] ALIGN2 = {
285 /* SST sst xxx --- */
286 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
287 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
288 0, S_IXOTH, S_IXOTH, 0 /* other */
291 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
293 static void parse_config_file(void)
295 struct BB_suid_config *sct_head;
296 struct BB_suid_config *sct;
308 assert(!suid_config); /* Should be set to NULL by bss init. */
311 if (ruid == 0) /* run by root - don't need to even read config file */
314 if ((stat(config_file, &st) != 0) /* No config file? */
315 || !S_ISREG(st.st_mode) /* Not a regular file? */
316 || (st.st_uid != 0) /* Not owned by root? */
317 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
318 || !(f = fopen_for_read(config_file)) /* Cannot open? */
323 suid_cfg_readable = 1;
330 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
332 if (ferror(f)) { /* Make sure it wasn't a read error. */
333 parse_error("reading");
336 suid_config = sct_head; /* Success, so set the pointer. */
340 lc++; /* Got a (partial) line. */
342 /* If a line is too long for our buffer, we consider it an error.
343 * The following test does mistreat one corner case though.
344 * If the final line of the file does not end with a newline and
345 * yet exactly fills the buffer, it will be treated as too long
346 * even though there isn't really a problem. But it isn't really
347 * worth adding code to deal with such an unlikely situation, and
348 * we do err on the side of caution. Besides, the line would be
349 * too long if it did end with a newline. */
350 if (!strchr(s, '\n') && !feof(f)) {
351 parse_error("line too long");
354 /* Trim leading and trailing whitespace, ignoring comments, and
355 * check if the resulting string is empty. */
356 s = get_trimmed_slice(s, strchrnul(s, '#'));
361 /* Check for a section header. */
364 /* Unlike the old code, we ignore leading and trailing
365 * whitespace for the section name. We also require that
366 * there are no stray characters after the closing bracket. */
368 if (!e /* Missing right bracket? */
369 || e[1] /* Trailing characters? */
370 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
372 parse_error("section header");
374 /* Right now we only have one section so just check it.
375 * If more sections are added in the future, please don't
376 * resort to cascading ifs with multiple strcasecmp calls.
377 * That kind of bloated code is all too common. A loop
378 * and a string table would be a better choice unless the
379 * number of sections is very small. */
380 if (strcasecmp(s, "SUID") == 0) {
384 section = -1; /* Unknown section so set to skip. */
388 /* Process sections. */
390 if (section == 1) { /* SUID */
391 /* Since we trimmed leading and trailing space above, we're
392 * now looking for strings of the form
393 * <key>[::space::]*=[::space::]*<value>
394 * where both key and value could contain inner whitespace. */
396 /* First get the key (an applet name in our case). */
399 s = get_trimmed_slice(s, e);
401 if (!e || !*s) { /* Missing '=' or empty key. */
402 parse_error("keyword");
405 /* Ok, we have an applet name. Process the rhs if this
406 * applet is currently built in and ignore it otherwise.
407 * Note: this can hide config file bugs which only pop
408 * up when the busybox configuration is changed. */
409 applet_no = find_applet_by_name(s);
410 if (applet_no >= 0) {
411 /* Note: We currently don't check for duplicates!
412 * The last config line for each applet will be the
413 * one used since we insert at the head of the list.
414 * I suppose this could be considered a feature. */
415 sct = xmalloc(sizeof(struct BB_suid_config));
416 sct->m_applet = applet_no;
418 sct->m_next = sct_head;
421 /* Get the specified mode. */
423 e = skip_whitespace(e+1);
425 for (i = 0; i < 3; i++) {
426 /* There are 4 chars + 1 nul for each of user/group/other. */
427 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
430 q = strchrnul(mode_chars + 5*i, *e++);
434 /* Adjust by -i to account for nul. */
435 sct->m_mode |= mode_mask[(q - mode_chars) - i];
438 /* Now get the the user/group info. */
440 s = skip_whitespace(e);
442 /* Note: we require whitespace between the mode and the
443 * user/group info. */
444 if ((s == e) || !(e = strchr(s, '.'))) {
445 parse_error("<uid>.<gid>");
449 /* We can't use get_ug_id here since it would exit()
450 * if a uid or gid was not found. Oh well... */
451 sct->m_uid = bb_strtoul(s, NULL, 10);
453 struct passwd *pwd = getpwnam(s);
457 sct->m_uid = pwd->pw_uid;
460 sct->m_gid = bb_strtoul(e, NULL, 10);
465 parse_error("group");
467 sct->m_gid = grp->gr_gid;
473 /* Unknown sections are ignored. */
475 /* Encountering configuration lines prior to seeing a
476 * section header is treated as an error. This is how
477 * the old code worked, but it may not be desirable.
478 * We may want to simply ignore such lines in case they
479 * are used in some future version of busybox. */
481 parse_error("keyword outside section");
487 fprintf(stderr, "Parse error in %s, line %d: %s\n",
488 config_file, lc, errmsg);
491 /* Release any allocated memory before returning. */
493 sct = sct_head->m_next;
499 static inline void parse_config_file(void)
501 IF_FEATURE_SUID(ruid = getuid();)
503 #endif /* FEATURE_SUID_CONFIG */
506 #if ENABLE_FEATURE_SUID
507 static void check_suid(int applet_no)
509 gid_t rgid; /* real gid */
511 if (ruid == 0) /* set by parse_config_file() */
512 return; /* run by root - no need to check more */
515 #if ENABLE_FEATURE_SUID_CONFIG
516 if (suid_cfg_readable) {
518 struct BB_suid_config *sct;
521 for (sct = suid_config; sct; sct = sct->m_next) {
522 if (sct->m_applet == applet_no)
525 goto check_need_suid;
528 if (sct->m_uid == ruid)
531 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
532 /* same group / in group */
535 if (!(m & S_IXOTH)) /* is x bit not set ? */
536 bb_error_msg_and_die("you have no permission to run this applet!");
538 /* _both_ sgid and group_exec have to be set for setegid */
539 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
541 /* else (no setegid) we will set egid = rgid */
543 /* We set effective AND saved ids. If saved-id is not set
544 * like we do below, seteiud(0) can still later succeed! */
545 if (setresgid(-1, rgid, rgid))
546 bb_perror_msg_and_die("setresgid");
548 /* do we have to set effective uid? */
550 if (sct->m_mode & S_ISUID)
552 /* else (no seteuid) we will set euid = ruid */
554 if (setresuid(-1, uid, uid))
555 bb_perror_msg_and_die("setresuid");
558 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
560 static bool onetime = 0;
564 fprintf(stderr, "Using fallback suid method\n");
570 if (APPLET_SUID(applet_no) == _BB_SUID_REQUIRE) {
571 /* Real uid is not 0. If euid isn't 0 too, suid bit
572 * is most probably not set on our executable */
574 bb_error_msg_and_die("must be suid to work properly");
575 } else if (APPLET_SUID(applet_no) == _BB_SUID_DROP) {
576 xsetgid(rgid); /* drop all privileges */
581 #define check_suid(x) ((void)0)
582 #endif /* FEATURE_SUID */
585 #if ENABLE_FEATURE_INSTALLER
586 static const char usr_bin [] ALIGN1 = "/usr/bin/";
587 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
588 static const char *const install_dir[] = {
589 &usr_bin [8], /* "/" */
590 &usr_bin [4], /* "/bin/" */
591 &usr_sbin[4], /* "/sbin/" */
597 /* create (sym)links for each applet */
598 static void install_links(const char *busybox, int use_symbolic_links,
599 char *custom_install_dir)
602 * this should be consistent w/ the enum,
603 * busybox.h::bb_install_loc_t, or else... */
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)
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"); /* reuse */
649 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
650 "and others. Licensed under GPLv2.\n"
651 "See source distribution for full notice.\n"
653 "Usage: busybox [function] [arguments]...\n"
654 " or: function [arguments]...\n"
656 "\tBusyBox is a multi-call binary that combines many common Unix\n"
657 "\tutilities into a single executable. Most people will create a\n"
658 "\tlink to busybox for each function they wish to use and BusyBox\n"
659 "\twill act like whatever it was invoked as.\n"
661 "Currently defined functions:\n"
665 /* prevent last comma to be in the very last pos */
668 int len2 = strlen(a) + 2;
669 if (col >= (int)output_width - len2) {
670 full_write2_str(",\n");
675 full_write2_str("\t");
677 full_write2_str(", ");
683 full_write2_str("\n\n");
687 if (strncmp(argv[1], "--list", 6) == 0) {
689 const char *a = applet_names;
692 #if ENABLE_FEATURE_INSTALLER
693 if (argv[1][6]) /* --list-path? */
694 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
697 full_write2_str("\n");
704 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
705 int use_symbolic_links;
707 busybox = xmalloc_readlink(bb_busybox_exec_path);
709 busybox = bb_busybox_exec_path;
710 /* busybox --install [-s] [DIR]: */
711 /* -s: make symlinks */
712 /* DIR: directory to install links to */
713 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
714 install_links(busybox, use_symbolic_links, argv[2]);
718 if (strcmp(argv[1], "--help") == 0) {
719 /* "busybox --help [<applet>]" */
722 /* convert to "<applet> --help" */
726 /* "busybox <applet> arg1 arg2 ..." */
729 /* We support "busybox /a/path/to/applet args..." too. Allows for
730 * "#!/bin/busybox"-style wrappers */
731 applet_name = bb_get_last_path_component_nostrip(argv[0]);
732 run_applet_and_exit(applet_name, argv);
734 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
735 full_write2_str(applet_name);
736 full_write2_str(": applet not found\n");
740 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
747 /* Reinit some shared global data */
748 xfunc_error_retval = EXIT_FAILURE;
750 applet_name = APPLET_NAME(applet_no);
751 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
752 /* Special case. POSIX says "test --help"
753 * should be no different from e.g. "test --foo". */
754 //TODO: just compare applet_no with APPLET_NO_test
755 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
758 if (ENABLE_FEATURE_SUID)
759 check_suid(applet_no);
760 exit(applet_main[applet_no](argc, argv));
763 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
765 int applet = find_applet_by_name(name);
767 run_applet_no_and_exit(applet, argv);
768 if (!strncmp(name, "busybox", 7))
769 exit(busybox_main(argv));
772 #endif /* !defined(SINGLE_APPLET_MAIN) */
776 #if ENABLE_BUILD_LIBBUSYBOX
777 int lbb_main(char **argv)
779 int main(int argc UNUSED_PARAM, char **argv)
782 /* Tweak malloc for reduced memory consumption */
784 # define PAGE_SIZE (4*1024) /* guess */
786 #ifdef M_TRIM_THRESHOLD
787 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
788 * to keep before releasing to the OS
789 * Default is way too big: 256k
791 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
793 #ifdef M_MMAP_THRESHOLD
794 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
795 * Default is too big: 256k
797 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
800 #if defined(SINGLE_APPLET_MAIN)
801 /* Only one applet is selected by the user! */
802 /* applet_names in this case is just "applet\0\0" */
803 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
804 return SINGLE_APPLET_MAIN(argc, argv);
806 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
809 /* NOMMU re-exec trick sets high-order bit in first byte of name */
810 if (argv[0][0] & 0x80) {
815 applet_name = argv[0];
816 if (applet_name[0] == '-')
818 applet_name = bb_basename(applet_name);
820 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
822 run_applet_and_exit(applet_name, argv);
824 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
825 full_write2_str(applet_name);
826 full_write2_str(": applet not found\n");