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
64 #endif /* SHOW_USAGE */
66 #if ENABLE_FEATURE_COMPRESS_USAGE
68 static const char packed_usage[] = { 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 static void full_write2_str(const char *str)
104 //xwrite_str(STDERR_FILENO, str);
105 write(STDERR_FILENO, str, strlen(str));
108 void FAST_FUNC bb_show_usage(void)
110 if (ENABLE_SHOW_USAGE) {
111 #ifdef SINGLE_APPLET_STR
112 /* Imagine that this applet is "true". Dont suck in printf! */
114 const char *usage_string = p = unpack_usage_messages();
117 full_write2_str("No help available.\n\n");
119 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
121 full_write2_str("\n\n");
123 if (ENABLE_FEATURE_CLEAN_UP)
124 dealloc_usage_messages((char*)usage_string);
127 const char *usage_string = p = unpack_usage_messages();
128 int ap = find_applet_by_name(applet_name);
130 if (ap < 0) /* never happens, paranoia */
133 while (*p++) continue;
136 full_write2_str(bb_banner);
137 full_write2_str(" multi-call binary.\n");
139 full_write2_str("\nNo help available.\n\n");
141 full_write2_str("\nUsage: ");
142 full_write2_str(applet_name);
143 full_write2_str(" ");
145 full_write2_str("\n\n");
147 if (ENABLE_FEATURE_CLEAN_UP)
148 dealloc_usage_messages((char*)usage_string);
155 /* NB: any char pointer will work as well, not necessarily applet_names */
156 static int applet_name_compare(const void *name, const void *v)
158 int i = (const char *)v - applet_names;
159 return strcmp(name, APPLET_NAME(i));
162 int FAST_FUNC find_applet_by_name(const char *name)
165 /* Do a binary search to find the applet entry given the name. */
167 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
170 return p - applet_names;
172 /* A version which does not pull in bsearch */
174 const char *p = applet_names;
175 while (i < NUM_APPLETS) {
176 if (strcmp(name, p) == 0)
186 void lbb_prepare(const char *applet
187 IF_FEATURE_INDIVIDUAL(, char **argv))
188 MAIN_EXTERNALLY_VISIBLE;
189 void lbb_prepare(const char *applet
190 IF_FEATURE_INDIVIDUAL(, char **argv))
193 (*(int **)&bb_errno) = __errno_location();
196 applet_name = applet;
198 /* Set locale for everybody except 'init' */
199 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
200 setlocale(LC_ALL, "");
202 #if ENABLE_FEATURE_INDIVIDUAL
203 /* Redundant for busybox (run_applet_and_exit covers that case)
204 * but needed for "individual applet" mode */
205 if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 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/" */
604 /* create (sym)links for each applet */
605 static void install_links(const char *busybox, int use_symbolic_links,
606 char *custom_install_dir)
609 * this should be consistent w/ the enum,
610 * busybox.h::bb_install_loc_t, or else... */
611 int (*lf)(const char *, const char *);
617 if (use_symbolic_links)
620 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
621 fpc = concat_path_file(
622 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
624 // debug: bb_error_msg("%slinking %s to busybox",
625 // use_symbolic_links ? "sym" : "", fpc);
626 rc = lf(busybox, fpc);
627 if (rc != 0 && errno != EEXIST) {
628 bb_simple_perror_msg(fpc);
634 # define install_links(x,y,z) ((void)0)
637 /* If we were called as "busybox..." */
638 static int busybox_main(char **argv)
641 /* Called without arguments */
644 unsigned output_width;
647 if (ENABLE_FEATURE_AUTOWIDTH) {
648 /* Obtain the terminal width */
649 get_terminal_width_height(0, &output_width, NULL);
653 full_write2_str(bb_banner); /* reuse const string */
654 full_write2_str(" multi-call binary.\n"); /* reuse */
656 "Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko\n"
657 "and others. Licensed under GPLv2.\n"
658 "See source distribution for full notice.\n"
660 "Usage: busybox [function] [arguments]...\n"
661 " or: function [arguments]...\n"
663 "\tBusyBox is a multi-call binary that combines many common Unix\n"
664 "\tutilities into a single executable. Most people will create a\n"
665 "\tlink to busybox for each function they wish to use and BusyBox\n"
666 "\twill act like whatever it was invoked as.\n"
668 "Currently defined functions:\n"
672 /* prevent last comma to be in the very last pos */
675 int len2 = strlen(a) + 2;
676 if (col >= (int)output_width - len2) {
677 full_write2_str(",\n");
682 full_write2_str("\t");
684 full_write2_str(", ");
690 full_write2_str("\n\n");
694 if (strncmp(argv[1], "--list", 6) == 0) {
696 const char *a = applet_names;
699 #if ENABLE_FEATURE_INSTALLER
700 if (argv[1][6]) /* --list-path? */
701 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
704 full_write2_str("\n");
711 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
712 int use_symbolic_links;
714 busybox = xmalloc_readlink(bb_busybox_exec_path);
716 busybox = bb_busybox_exec_path;
717 /* busybox --install [-s] [DIR]: */
718 /* -s: make symlinks */
719 /* DIR: directory to install links to */
720 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
721 install_links(busybox, use_symbolic_links, argv[2]);
725 if (strcmp(argv[1], "--help") == 0) {
726 /* "busybox --help [<applet>]" */
729 /* convert to "<applet> --help" */
733 /* "busybox <applet> arg1 arg2 ..." */
736 /* We support "busybox /a/path/to/applet args..." too. Allows for
737 * "#!/bin/busybox"-style wrappers */
738 applet_name = bb_get_last_path_component_nostrip(argv[0]);
739 run_applet_and_exit(applet_name, argv);
741 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
742 full_write2_str(applet_name);
743 full_write2_str(": applet not found\n");
747 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
754 /* Reinit some shared global data */
755 xfunc_error_retval = EXIT_FAILURE;
757 applet_name = APPLET_NAME(applet_no);
758 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
759 /* Special case. POSIX says "test --help"
760 * should be no different from e.g. "test --foo". */
761 //TODO: just compare applet_no with APPLET_NO_test
762 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
765 if (ENABLE_FEATURE_SUID)
766 check_suid(applet_no);
767 exit(applet_main[applet_no](argc, argv));
770 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
772 int applet = find_applet_by_name(name);
774 run_applet_no_and_exit(applet, argv);
775 if (!strncmp(name, "busybox", 7))
776 exit(busybox_main(argv));
779 #endif /* !defined(SINGLE_APPLET_MAIN) */
783 #if ENABLE_BUILD_LIBBUSYBOX
784 int lbb_main(char **argv)
786 int main(int argc UNUSED_PARAM, char **argv)
789 /* Tweak malloc for reduced memory consumption */
791 # define PAGE_SIZE (4*1024) /* guess */
793 #ifdef M_TRIM_THRESHOLD
794 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
795 * to keep before releasing to the OS
796 * Default is way too big: 256k
798 mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
800 #ifdef M_MMAP_THRESHOLD
801 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
802 * Default is too big: 256k
804 mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
807 #if defined(SINGLE_APPLET_MAIN)
808 /* Only one applet is selected by the user! */
809 /* applet_names in this case is just "applet\0\0" */
810 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
811 return SINGLE_APPLET_MAIN(argc, argv);
813 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
816 /* NOMMU re-exec trick sets high-order bit in first byte of name */
817 if (argv[0][0] & 0x80) {
822 applet_name = argv[0];
823 if (applet_name[0] == '-')
825 applet_name = bb_basename(applet_name);
827 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
829 run_applet_and_exit(applet_name, argv);
831 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
832 full_write2_str(applet_name);
833 full_write2_str(": applet not found\n");