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 */
36 /* Try to pull in PAGE_SIZE */
38 # include <sys/user.h>
40 #ifdef __GNU__ /* Hurd */
41 # include <mach/vm_param.h>
45 /* Declare <applet>_main() */
51 /* Include generated applet names, pointers to <applet>_main, etc */
52 #include "applet_tables.h"
53 /* ...and if applet_tables generator says we have only one applet... */
54 #ifdef SINGLE_APPLET_MAIN
55 # undef ENABLE_FEATURE_INDIVIDUAL
56 # define ENABLE_FEATURE_INDIVIDUAL 1
57 # undef IF_FEATURE_INDIVIDUAL
58 # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
62 #include "usage_compressed.h"
64 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
65 static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
67 # define usage_messages 0
70 #if ENABLE_FEATURE_COMPRESS_USAGE
72 static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
74 static const char *unpack_usage_messages(void)
82 /* inbuf: */ packed_usage,
83 /* len: */ sizeof(packed_usage));
84 /* read_bunzip can longjmp to start_bunzip, and ultimately
85 * end up here with i != 0 on read data errors! Not trivial */
87 /* Cannot use xmalloc: will leak bd in NOFORK case! */
88 outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
90 read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
95 # define dealloc_usage_messages(s) free(s)
99 # define unpack_usage_messages() usage_messages
100 # define dealloc_usage_messages(s) ((void)(s))
102 #endif /* FEATURE_COMPRESS_USAGE */
105 void FAST_FUNC bb_show_usage(void)
107 if (ENABLE_SHOW_USAGE) {
108 #ifdef SINGLE_APPLET_STR
109 /* Imagine that this applet is "true". Dont suck in printf! */
110 const char *usage_string = unpack_usage_messages();
112 if (*usage_string == '\b') {
113 full_write2_str("No help available.\n\n");
115 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
116 full_write2_str(usage_string);
117 full_write2_str("\n\n");
119 if (ENABLE_FEATURE_CLEAN_UP)
120 dealloc_usage_messages((char*)usage_string);
123 const char *usage_string = p = unpack_usage_messages();
124 int ap = find_applet_by_name(applet_name);
126 if (ap < 0) /* never happens, paranoia */
129 while (*p++) continue;
132 full_write2_str(bb_banner);
133 full_write2_str(" multi-call binary.\n");
135 full_write2_str("\nNo help available.\n\n");
137 full_write2_str("\nUsage: ");
138 full_write2_str(applet_name);
139 full_write2_str(" ");
141 full_write2_str("\n\n");
143 if (ENABLE_FEATURE_CLEAN_UP)
144 dealloc_usage_messages((char*)usage_string);
151 /* NB: any char pointer will work as well, not necessarily applet_names */
152 static int applet_name_compare(const void *name, const void *v)
154 int i = (const char *)v - applet_names;
155 return strcmp(name, APPLET_NAME(i));
158 int FAST_FUNC find_applet_by_name(const char *name)
161 /* Do a binary search to find the applet entry given the name. */
163 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
166 return p - applet_names;
168 /* A version which does not pull in bsearch */
170 const char *p = applet_names;
171 while (i < NUM_APPLETS) {
172 if (strcmp(name, p) == 0)
182 void lbb_prepare(const char *applet
183 IF_FEATURE_INDIVIDUAL(, char **argv))
184 MAIN_EXTERNALLY_VISIBLE;
185 void lbb_prepare(const char *applet
186 IF_FEATURE_INDIVIDUAL(, char **argv))
189 (*(int **)&bb_errno) = __errno_location();
192 applet_name = applet;
194 /* Set locale for everybody except 'init' */
195 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
196 setlocale(LC_ALL, "");
198 #if ENABLE_FEATURE_INDIVIDUAL
199 /* Redundant for busybox (run_applet_and_exit covers that case)
200 * but needed for "individual applet" mode */
203 && strcmp(argv[1], "--help") == 0
204 && strncmp(applet, "busybox", 7) != 0
206 /* Special case. POSIX says "test --help"
207 * should be no different from e.g. "test --foo". */
208 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
214 /* The code below can well be in applets/applets.c, as it is used only
215 * for busybox binary, not "individual" binaries.
216 * However, keeping it here and linking it into libbusybox.so
217 * (together with remaining tiny applets/applets.o)
218 * makes it possible to avoid --whole-archive at link time.
219 * This makes (shared busybox) + libbusybox smaller.
220 * (--gc-sections would be even better....)
223 const char *applet_name;
229 /* If not built as a single-applet executable... */
230 #if !defined(SINGLE_APPLET_MAIN)
232 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
234 # if ENABLE_FEATURE_SUID_CONFIG
236 /* applets[] is const, so we have to define this "override" structure */
237 static struct BB_suid_config {
242 struct BB_suid_config *m_next;
245 static bool suid_cfg_readable;
247 /* check if u is member of group g */
248 static int ingroup(uid_t u, gid_t g)
250 struct group *grp = getgrgid(g);
255 for (mem = grp->gr_mem; *mem; mem++) {
256 struct passwd *pwd = getpwnam(*mem);
258 if (pwd && (pwd->pw_uid == u))
265 /* This should probably be a libbb routine. In that case,
266 * I'd probably rename it to something like bb_trimmed_slice.
268 static char *get_trimmed_slice(char *s, char *e)
270 /* First, consider the value at e to be nul and back up until we
271 * reach a non-space char. Set the char after that (possibly at
272 * the original e) to nul. */
280 /* Next, advance past all leading space and return a ptr to the
281 * first non-space char; possibly the terminating nul. */
282 return skip_whitespace(s);
285 /* Don't depend on the tools to combine strings. */
286 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
288 /* We don't supply a value for the nul, so an index adjustment is
289 * necessary below. Also, we use unsigned short here to save some
290 * space even though these are really mode_t values. */
291 static const unsigned short mode_mask[] ALIGN2 = {
292 /* SST sst xxx --- */
293 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
294 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
295 0, S_IXOTH, S_IXOTH, 0 /* other */
298 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
300 static void parse_config_file(void)
302 struct BB_suid_config *sct_head;
303 struct BB_suid_config *sct;
315 assert(!suid_config); /* Should be set to NULL by bss init. */
318 if (ruid == 0) /* run by root - don't need to even read config file */
321 if ((stat(config_file, &st) != 0) /* No config file? */
322 || !S_ISREG(st.st_mode) /* Not a regular file? */
323 || (st.st_uid != 0) /* Not owned by root? */
324 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
325 || !(f = fopen_for_read(config_file)) /* Cannot open? */
330 suid_cfg_readable = 1;
337 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
339 if (ferror(f)) { /* Make sure it wasn't a read error. */
340 parse_error("reading");
343 suid_config = sct_head; /* Success, so set the pointer. */
347 lc++; /* Got a (partial) line. */
349 /* If a line is too long for our buffer, we consider it an error.
350 * The following test does mistreat one corner case though.
351 * If the final line of the file does not end with a newline and
352 * yet exactly fills the buffer, it will be treated as too long
353 * even though there isn't really a problem. But it isn't really
354 * worth adding code to deal with such an unlikely situation, and
355 * we do err on the side of caution. Besides, the line would be
356 * too long if it did end with a newline. */
357 if (!strchr(s, '\n') && !feof(f)) {
358 parse_error("line too long");
361 /* Trim leading and trailing whitespace, ignoring comments, and
362 * check if the resulting string is empty. */
363 s = get_trimmed_slice(s, strchrnul(s, '#'));
368 /* Check for a section header. */
371 /* Unlike the old code, we ignore leading and trailing
372 * whitespace for the section name. We also require that
373 * there are no stray characters after the closing bracket. */
375 if (!e /* Missing right bracket? */
376 || e[1] /* Trailing characters? */
377 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
379 parse_error("section header");
381 /* Right now we only have one section so just check it.
382 * If more sections are added in the future, please don't
383 * resort to cascading ifs with multiple strcasecmp calls.
384 * That kind of bloated code is all too common. A loop
385 * and a string table would be a better choice unless the
386 * number of sections is very small. */
387 if (strcasecmp(s, "SUID") == 0) {
391 section = -1; /* Unknown section so set to skip. */
395 /* Process sections. */
397 if (section == 1) { /* SUID */
398 /* Since we trimmed leading and trailing space above, we're
399 * now looking for strings of the form
400 * <key>[::space::]*=[::space::]*<value>
401 * where both key and value could contain inner whitespace. */
403 /* First get the key (an applet name in our case). */
406 s = get_trimmed_slice(s, e);
408 if (!e || !*s) { /* Missing '=' or empty key. */
409 parse_error("keyword");
412 /* Ok, we have an applet name. Process the rhs if this
413 * applet is currently built in and ignore it otherwise.
414 * Note: this can hide config file bugs which only pop
415 * up when the busybox configuration is changed. */
416 applet_no = find_applet_by_name(s);
417 if (applet_no >= 0) {
418 /* Note: We currently don't check for duplicates!
419 * The last config line for each applet will be the
420 * one used since we insert at the head of the list.
421 * I suppose this could be considered a feature. */
422 sct = xmalloc(sizeof(struct BB_suid_config));
423 sct->m_applet = applet_no;
425 sct->m_next = sct_head;
428 /* Get the specified mode. */
430 e = skip_whitespace(e+1);
432 for (i = 0; i < 3; i++) {
433 /* There are 4 chars + 1 nul for each of user/group/other. */
434 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
437 q = strchrnul(mode_chars + 5*i, *e++);
441 /* Adjust by -i to account for nul. */
442 sct->m_mode |= mode_mask[(q - mode_chars) - i];
445 /* Now get the the user/group info. */
447 s = skip_whitespace(e);
449 /* Note: we require whitespace between the mode and the
450 * user/group info. */
451 if ((s == e) || !(e = strchr(s, '.'))) {
452 parse_error("<uid>.<gid>");
456 /* We can't use get_ug_id here since it would exit()
457 * if a uid or gid was not found. Oh well... */
458 sct->m_uid = bb_strtoul(s, NULL, 10);
460 struct passwd *pwd = getpwnam(s);
464 sct->m_uid = pwd->pw_uid;
467 sct->m_gid = bb_strtoul(e, NULL, 10);
472 parse_error("group");
474 sct->m_gid = grp->gr_gid;
480 /* Unknown sections are ignored. */
482 /* Encountering configuration lines prior to seeing a
483 * section header is treated as an error. This is how
484 * the old code worked, but it may not be desirable.
485 * We may want to simply ignore such lines in case they
486 * are used in some future version of busybox. */
488 parse_error("keyword outside section");
494 fprintf(stderr, "Parse error in %s, line %d: %s\n",
495 config_file, lc, errmsg);
498 /* Release any allocated memory before returning. */
500 sct = sct_head->m_next;
506 static inline void parse_config_file(void)
508 IF_FEATURE_SUID(ruid = getuid();)
510 # endif /* FEATURE_SUID_CONFIG */
513 # if ENABLE_FEATURE_SUID
514 static void check_suid(int applet_no)
516 gid_t rgid; /* real gid */
518 if (ruid == 0) /* set by parse_config_file() */
519 return; /* run by root - no need to check more */
522 # if ENABLE_FEATURE_SUID_CONFIG
523 if (suid_cfg_readable) {
525 struct BB_suid_config *sct;
528 for (sct = suid_config; sct; sct = sct->m_next) {
529 if (sct->m_applet == applet_no)
532 goto check_need_suid;
535 if (sct->m_uid == ruid)
538 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
539 /* same group / in group */
542 if (!(m & S_IXOTH)) /* is x bit not set ? */
543 bb_error_msg_and_die("you have no permission to run this applet!");
545 /* _both_ sgid and group_exec have to be set for setegid */
546 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
548 /* else (no setegid) we will set egid = rgid */
550 /* We set effective AND saved ids. If saved-id is not set
551 * like we do below, seteiud(0) can still later succeed! */
552 if (setresgid(-1, rgid, rgid))
553 bb_perror_msg_and_die("setresgid");
555 /* do we have to set effective uid? */
557 if (sct->m_mode & S_ISUID)
559 /* else (no seteuid) we will set euid = ruid */
561 if (setresuid(-1, uid, uid))
562 bb_perror_msg_and_die("setresuid");
565 # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
567 static bool onetime = 0;
571 fprintf(stderr, "Using fallback suid method\n");
577 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
578 /* Real uid is not 0. If euid isn't 0 too, suid bit
579 * is most probably not set on our executable */
581 bb_error_msg_and_die("must be suid to work properly");
582 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
583 xsetgid(rgid); /* drop all privileges */
588 # define check_suid(x) ((void)0)
589 # endif /* FEATURE_SUID */
592 # if ENABLE_FEATURE_INSTALLER
593 static const char usr_bin [] ALIGN1 = "/usr/bin/";
594 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
595 static const char *const install_dir[] = {
596 &usr_bin [8], /* "/" */
597 &usr_bin [4], /* "/bin/" */
598 &usr_sbin[4] /* "/sbin/" */
599 # if !ENABLE_INSTALL_NO_USR
605 /* create (sym)links for each applet */
606 static void install_links(const char *busybox, int use_symbolic_links,
607 char *custom_install_dir)
610 * this should be consistent w/ the enum,
611 * busybox.h::bb_install_loc_t, or else... */
612 int (*lf)(const char *, const char *);
618 if (use_symbolic_links)
621 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
622 fpc = concat_path_file(
623 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
625 // debug: bb_error_msg("%slinking %s to busybox",
626 // use_symbolic_links ? "sym" : "", fpc);
627 rc = lf(busybox, fpc);
628 if (rc != 0 && errno != EEXIST) {
629 bb_simple_perror_msg(fpc);
635 # define install_links(x,y,z) ((void)0)
638 /* If we were called as "busybox..." */
639 static int busybox_main(char **argv)
642 /* Called without arguments */
645 unsigned output_width;
648 if (ENABLE_FEATURE_AUTOWIDTH) {
649 /* Obtain the terminal width */
650 get_terminal_width_height(0, &output_width, NULL);
654 full_write2_str(bb_banner); /* reuse const string */
655 full_write2_str(" multi-call binary.\n"); /* reuse */
657 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
658 "and others. Licensed under GPLv2.\n"
659 "See source distribution for full notice.\n"
661 "Usage: busybox [function] [arguments]...\n"
662 " or: busybox --list[-full]\n"
663 " or: function [arguments]...\n"
665 "\tBusyBox is a multi-call binary that combines many common Unix\n"
666 "\tutilities into a single executable. Most people will create a\n"
667 "\tlink to busybox for each function they wish to use and BusyBox\n"
668 "\twill act like whatever it was invoked as.\n"
670 "Currently defined functions:\n"
674 /* prevent last comma to be in the very last pos */
677 int len2 = strlen(a) + 2;
678 if (col >= (int)output_width - len2) {
679 full_write2_str(",\n");
684 full_write2_str("\t");
686 full_write2_str(", ");
692 full_write2_str("\n\n");
696 if (strncmp(argv[1], "--list", 6) == 0) {
698 const char *a = applet_names;
701 # if ENABLE_FEATURE_INSTALLER
702 if (argv[1][6]) /* --list-path? */
703 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
706 full_write2_str("\n");
713 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
714 int use_symbolic_links;
717 busybox = xmalloc_readlink(bb_busybox_exec_path);
719 /* bb_busybox_exec_path is usually "/proc/self/exe".
720 * In chroot, readlink("/proc/self/exe") usually fails.
721 * In such case, better use argv[0] as symlink target
722 * if it is a full path name.
724 if (argv[0][0] == '/')
727 busybox = bb_busybox_exec_path;
729 /* busybox --install [-s] [DIR]:
731 * DIR: directory to install links to
733 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
734 install_links(busybox, use_symbolic_links, argv[2]);
738 if (strcmp(argv[1], "--help") == 0) {
739 /* "busybox --help [<applet>]" */
742 /* convert to "<applet> --help" */
746 /* "busybox <applet> arg1 arg2 ..." */
749 /* We support "busybox /a/path/to/applet args..." too. Allows for
750 * "#!/bin/busybox"-style wrappers */
751 applet_name = bb_get_last_path_component_nostrip(argv[0]);
752 run_applet_and_exit(applet_name, argv);
754 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
755 full_write2_str(applet_name);
756 full_write2_str(": applet not found\n");
760 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
767 /* Reinit some shared global data */
768 xfunc_error_retval = EXIT_FAILURE;
770 applet_name = APPLET_NAME(applet_no);
771 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
772 /* Special case. POSIX says "test --help"
773 * should be no different from e.g. "test --foo". */
774 //TODO: just compare applet_no with APPLET_NO_test
775 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
778 if (ENABLE_FEATURE_SUID)
779 check_suid(applet_no);
780 exit(applet_main[applet_no](argc, argv));
783 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
785 int applet = find_applet_by_name(name);
787 run_applet_no_and_exit(applet, argv);
788 if (strncmp(name, "busybox", 7) == 0)
789 exit(busybox_main(argv));
792 #endif /* !defined(SINGLE_APPLET_MAIN) */
796 #if ENABLE_BUILD_LIBBUSYBOX
797 int lbb_main(char **argv)
799 int main(int argc UNUSED_PARAM, char **argv)
802 /* Tweak malloc for reduced memory consumption */
804 # define PAGE_SIZE (4*1024) /* guess */
806 #ifdef M_TRIM_THRESHOLD
807 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
808 * to keep before releasing to the OS
809 * Default is way too big: 256k
811 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
813 #ifdef M_MMAP_THRESHOLD
814 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
815 * Default is too big: 256k
817 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
821 /* NOMMU re-exec trick sets high-order bit in first byte of name */
822 if (argv[0][0] & 0x80) {
828 #if defined(SINGLE_APPLET_MAIN)
829 /* Only one applet is selected in .config */
830 if (argv[1] && strncmp(argv[0], "busybox", 7) == 0) {
831 /* "busybox <applet> <params>" should still work as expected */
834 /* applet_names in this case is just "applet\0\0" */
835 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
836 return SINGLE_APPLET_MAIN(argc, argv);
838 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
840 applet_name = argv[0];
841 if (applet_name[0] == '-')
843 applet_name = bb_basename(applet_name);
845 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
847 run_applet_and_exit(applet_name, argv);
849 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
850 full_write2_str(applet_name);
851 full_write2_str(": applet not found\n");