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. :(
34 /* Declare <applet>_main() */
39 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
40 /* Define usage_messages[] */
41 static const char usage_messages[] ALIGN1 = ""
48 #define usage_messages 0
49 #endif /* SHOW_USAGE */
52 /* Include generated applet names, pointers to <applet>_main, etc */
53 #include "applet_tables.h"
54 /* ...and if applet_tables generator says we have only one applet... */
55 #ifdef SINGLE_APPLET_MAIN
56 #undef ENABLE_FEATURE_INDIVIDUAL
57 #define ENABLE_FEATURE_INDIVIDUAL 1
58 #undef USE_FEATURE_INDIVIDUAL
59 #define USE_FEATURE_INDIVIDUAL(...) __VA_ARGS__
63 #if ENABLE_FEATURE_COMPRESS_USAGE
65 #include "usage_compressed.h"
66 #include "unarchive.h"
68 static const char *unpack_usage_messages(void)
76 /* inbuf: */ (void *)packed_usage,
77 /* len: */ sizeof(packed_usage));
78 /* read_bunzip can longjmp to start_bunzip, and ultimately
79 * end up here with i != 0 on read data errors! Not trivial */
81 /* Cannot use xmalloc: will leak bd in NOFORK case! */
82 outbuf = malloc_or_warn(SIZEOF_usage_messages);
84 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
89 #define dealloc_usage_messages(s) free(s)
93 #define unpack_usage_messages() usage_messages
94 #define dealloc_usage_messages(s) ((void)(s))
96 #endif /* FEATURE_COMPRESS_USAGE */
99 static void full_write2_str(const char *str)
101 full_write(STDERR_FILENO, str, strlen(str));
104 void FAST_FUNC bb_show_usage(void)
106 if (ENABLE_SHOW_USAGE) {
107 #ifdef SINGLE_APPLET_STR
108 /* Imagine that this applet is "true". Dont suck in printf! */
110 const char *usage_string = p = unpack_usage_messages();
113 full_write2_str("\nNo help available.\n\n");
115 full_write2_str("\nUsage: "SINGLE_APPLET_STR" ");
117 full_write2_str("\n\n");
119 dealloc_usage_messages((char*)usage_string);
122 const char *usage_string = p = unpack_usage_messages();
123 int ap = find_applet_by_name(applet_name);
125 if (ap < 0) /* never happens, paranoia */
128 while (*p++) continue;
131 full_write2_str(bb_banner);
132 full_write2_str(" multi-call binary\n");
134 full_write2_str("\nNo help available.\n\n");
136 full_write2_str("\nUsage: ");
137 full_write2_str(applet_name);
138 full_write2_str(" ");
140 full_write2_str("\n\n");
142 dealloc_usage_messages((char*)usage_string);
149 /* NB: any char pointer will work as well, not necessarily applet_names */
150 static int applet_name_compare(const void *name, const void *v)
152 int i = (const char *)v - applet_names;
153 return strcmp(name, APPLET_NAME(i));
156 int FAST_FUNC find_applet_by_name(const char *name)
159 /* Do a binary search to find the applet entry given the name. */
161 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
164 return p - applet_names;
166 /* A version which does not pull in bsearch */
168 const char *p = applet_names;
169 while (i < NUM_APPLETS) {
170 if (strcmp(name, p) == 0)
180 void lbb_prepare(const char *applet
181 USE_FEATURE_INDIVIDUAL(, char **argv))
182 MAIN_EXTERNALLY_VISIBLE;
183 void lbb_prepare(const char *applet
184 USE_FEATURE_INDIVIDUAL(, char **argv))
187 (*(int **)&bb_errno) = __errno_location();
190 applet_name = applet;
192 /* Set locale for everybody except 'init' */
193 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
194 setlocale(LC_ALL, "");
196 #if ENABLE_FEATURE_INDIVIDUAL
197 /* Redundant for busybox (run_applet_and_exit covers that case)
198 * but needed for "individual applet" mode */
199 if (argv[1] && strcmp(argv[1], "--help") == 0)
204 /* The code below can well be in applets/applets.c, as it is used only
205 * for busybox binary, not "individual" binaries.
206 * However, keeping it here and linking it into libbusybox.so
207 * (together with remaining tiny applets/applets.o)
208 * makes it possible to avoid --whole-archive at link time.
209 * This makes (shared busybox) + libbusybox smaller.
210 * (--gc-sections would be even better....)
213 const char *applet_name;
219 /* If not built as a single-applet executable... */
220 #if !defined(SINGLE_APPLET_MAIN)
222 USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
224 #if ENABLE_FEATURE_SUID_CONFIG
226 /* applets[] is const, so we have to define this "override" structure */
227 static struct BB_suid_config {
232 struct BB_suid_config *m_next;
235 static bool suid_cfg_readable;
237 /* check if u is member of group g */
238 static int ingroup(uid_t u, gid_t g)
240 struct group *grp = getgrgid(g);
245 for (mem = grp->gr_mem; *mem; mem++) {
246 struct passwd *pwd = getpwnam(*mem);
248 if (pwd && (pwd->pw_uid == u))
255 /* This should probably be a libbb routine. In that case,
256 * I'd probably rename it to something like bb_trimmed_slice.
258 static char *get_trimmed_slice(char *s, char *e)
260 /* First, consider the value at e to be nul and back up until we
261 * reach a non-space char. Set the char after that (possibly at
262 * the original e) to nul. */
270 /* Next, advance past all leading space and return a ptr to the
271 * first non-space char; possibly the terminating nul. */
272 return skip_whitespace(s);
275 /* Don't depend on the tools to combine strings. */
276 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
278 /* We don't supply a value for the nul, so an index adjustment is
279 * necessary below. Also, we use unsigned short here to save some
280 * space even though these are really mode_t values. */
281 static const unsigned short mode_mask[] ALIGN2 = {
282 /* SST sst xxx --- */
283 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
284 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
285 0, S_IXOTH, S_IXOTH, 0 /* other */
288 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
290 static void parse_config_file(void)
292 struct BB_suid_config *sct_head;
293 struct BB_suid_config *sct;
305 assert(!suid_config); /* Should be set to NULL by bss init. */
308 if (ruid == 0) /* run by root - don't need to even read config file */
311 if ((stat(config_file, &st) != 0) /* No config file? */
312 || !S_ISREG(st.st_mode) /* Not a regular file? */
313 || (st.st_uid != 0) /* Not owned by root? */
314 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
315 || !(f = fopen(config_file, "r")) /* Cannot open? */
320 suid_cfg_readable = 1;
327 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
329 if (ferror(f)) { /* Make sure it wasn't a read error. */
330 parse_error("reading");
333 suid_config = sct_head; /* Success, so set the pointer. */
337 lc++; /* Got a (partial) line. */
339 /* If a line is too long for our buffer, we consider it an error.
340 * The following test does mistreat one corner case though.
341 * If the final line of the file does not end with a newline and
342 * yet exactly fills the buffer, it will be treated as too long
343 * even though there isn't really a problem. But it isn't really
344 * worth adding code to deal with such an unlikely situation, and
345 * we do err on the side of caution. Besides, the line would be
346 * too long if it did end with a newline. */
347 if (!strchr(s, '\n') && !feof(f)) {
348 parse_error("line too long");
351 /* Trim leading and trailing whitespace, ignoring comments, and
352 * check if the resulting string is empty. */
353 s = get_trimmed_slice(s, strchrnul(s, '#'));
358 /* Check for a section header. */
361 /* Unlike the old code, we ignore leading and trailing
362 * whitespace for the section name. We also require that
363 * there are no stray characters after the closing bracket. */
365 if (!e /* Missing right bracket? */
366 || e[1] /* Trailing characters? */
367 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
369 parse_error("section header");
371 /* Right now we only have one section so just check it.
372 * If more sections are added in the future, please don't
373 * resort to cascading ifs with multiple strcasecmp calls.
374 * That kind of bloated code is all too common. A loop
375 * and a string table would be a better choice unless the
376 * number of sections is very small. */
377 if (strcasecmp(s, "SUID") == 0) {
381 section = -1; /* Unknown section so set to skip. */
385 /* Process sections. */
387 if (section == 1) { /* SUID */
388 /* Since we trimmed leading and trailing space above, we're
389 * now looking for strings of the form
390 * <key>[::space::]*=[::space::]*<value>
391 * where both key and value could contain inner whitespace. */
393 /* First get the key (an applet name in our case). */
396 s = get_trimmed_slice(s, e);
398 if (!e || !*s) { /* Missing '=' or empty key. */
399 parse_error("keyword");
402 /* Ok, we have an applet name. Process the rhs if this
403 * applet is currently built in and ignore it otherwise.
404 * Note: this can hide config file bugs which only pop
405 * up when the busybox configuration is changed. */
406 applet_no = find_applet_by_name(s);
407 if (applet_no >= 0) {
408 /* Note: We currently don't check for duplicates!
409 * The last config line for each applet will be the
410 * one used since we insert at the head of the list.
411 * I suppose this could be considered a feature. */
412 sct = xmalloc(sizeof(struct BB_suid_config));
413 sct->m_applet = applet_no;
415 sct->m_next = sct_head;
418 /* Get the specified mode. */
420 e = skip_whitespace(e+1);
422 for (i = 0; i < 3; i++) {
423 /* There are 4 chars + 1 nul for each of user/group/other. */
424 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
427 q = strchrnul(mode_chars + 5*i, *e++);
431 /* Adjust by -i to account for nul. */
432 sct->m_mode |= mode_mask[(q - mode_chars) - i];
435 /* Now get the the user/group info. */
437 s = skip_whitespace(e);
439 /* Note: we require whitespace between the mode and the
440 * user/group info. */
441 if ((s == e) || !(e = strchr(s, '.'))) {
442 parse_error("<uid>.<gid>");
446 /* We can't use get_ug_id here since it would exit()
447 * if a uid or gid was not found. Oh well... */
448 sct->m_uid = bb_strtoul(s, NULL, 10);
450 struct passwd *pwd = getpwnam(s);
454 sct->m_uid = pwd->pw_uid;
457 sct->m_gid = bb_strtoul(e, NULL, 10);
462 parse_error("group");
464 sct->m_gid = grp->gr_gid;
470 /* Unknown sections are ignored. */
472 /* Encountering configuration lines prior to seeing a
473 * section header is treated as an error. This is how
474 * the old code worked, but it may not be desirable.
475 * We may want to simply ignore such lines in case they
476 * are used in some future version of busybox. */
478 parse_error("keyword outside section");
484 fprintf(stderr, "Parse error in %s, line %d: %s\n",
485 config_file, lc, errmsg);
488 /* Release any allocated memory before returning. */
490 sct = sct_head->m_next;
496 static inline void parse_config_file(void)
498 USE_FEATURE_SUID(ruid = getuid();)
500 #endif /* FEATURE_SUID_CONFIG */
503 #if ENABLE_FEATURE_SUID
504 static void check_suid(int applet_no)
506 gid_t rgid; /* real gid */
508 if (ruid == 0) /* set by parse_config_file() */
509 return; /* run by root - no need to check more */
512 #if ENABLE_FEATURE_SUID_CONFIG
513 if (suid_cfg_readable) {
515 struct BB_suid_config *sct;
518 for (sct = suid_config; sct; sct = sct->m_next) {
519 if (sct->m_applet == applet_no)
522 goto check_need_suid;
525 if (sct->m_uid == ruid)
528 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
529 /* same group / in group */
532 if (!(m & S_IXOTH)) /* is x bit not set ? */
533 bb_error_msg_and_die("you have no permission to run this applet!");
535 /* _both_ sgid and group_exec have to be set for setegid */
536 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
538 /* else (no setegid) we will set egid = rgid */
540 /* We set effective AND saved ids. If saved-id is not set
541 * like we do below, seteiud(0) can still later succeed! */
542 if (setresgid(-1, rgid, rgid))
543 bb_perror_msg_and_die("setresgid");
545 /* do we have to set effective uid? */
547 if (sct->m_mode & S_ISUID)
549 /* else (no seteuid) we will set euid = ruid */
551 if (setresuid(-1, uid, uid))
552 bb_perror_msg_and_die("setresuid");
555 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
557 static bool onetime = 0;
561 fprintf(stderr, "Using fallback suid method\n");
567 if (APPLET_SUID(applet_no) == _BB_SUID_ALWAYS) {
568 /* Real uid is not 0. If euid isn't 0 too, suid bit
569 * is most probably not set on our executable */
571 bb_error_msg_and_die("must be suid to work properly");
572 } else if (APPLET_SUID(applet_no) == _BB_SUID_NEVER) {
573 xsetgid(rgid); /* drop all privileges */
578 #define check_suid(x) ((void)0)
579 #endif /* FEATURE_SUID */
582 #if ENABLE_FEATURE_INSTALLER
583 /* create (sym)links for each applet */
584 static void install_links(const char *busybox, int use_symbolic_links)
587 * this should be consistent w/ the enum,
588 * busybox.h::bb_install_loc_t, or else... */
589 static const char usr_bin [] ALIGN1 = "/usr/bin";
590 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
591 static const char *const install_dir[] = {
592 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
593 &usr_bin [4], /* "/bin" */
594 &usr_sbin[4], /* "/sbin" */
599 int (*lf)(const char *, const char *);
605 if (use_symbolic_links)
608 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
609 fpc = concat_path_file(
610 install_dir[APPLET_INSTALL_LOC(i)],
612 // debug: bb_error_msg("%slinking %s to busybox",
613 // use_symbolic_links ? "sym" : "", fpc);
614 rc = lf(busybox, fpc);
615 if (rc != 0 && errno != EEXIST) {
616 bb_simple_perror_msg(fpc);
622 #define install_links(x,y) ((void)0)
623 #endif /* FEATURE_INSTALLER */
625 /* If we were called as "busybox..." */
626 static int busybox_main(char **argv)
629 /* Called without arguments */
631 unsigned col, output_width;
634 if (ENABLE_FEATURE_AUTOWIDTH) {
635 /* Obtain the terminal width */
636 get_terminal_width_height(0, &output_width, NULL);
638 /* leading tab and room to wrap */
639 output_width -= MAX_APPLET_NAME_LEN + 8;
642 full_write2_str(bb_banner); /* reuse const string... */
643 full_write2_str(" multi-call binary\n"
644 "Copyright (C) 1998-2008 Erik Andersen, Rob Landley, Denys Vlasenko\n"
645 "and others. Licensed under GPLv2.\n"
646 "See source distribution for full notice.\n"
648 "Usage: busybox [function] [arguments]...\n"
649 " or: function [arguments]...\n"
651 "\tBusyBox is a multi-call binary that combines many common Unix\n"
652 "\tutilities into a single executable. Most people will create a\n"
653 "\tlink to busybox for each function they wish to use and BusyBox\n"
654 "\twill act like whatever it was invoked as!\n"
656 "Currently defined functions:\n");
661 if (col > output_width) {
662 full_write2_str(",\n");
665 full_write2_str(col ? ", " : "\t");
671 full_write2_str("\n\n");
675 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
677 busybox = xmalloc_readlink(bb_busybox_exec_path);
679 busybox = bb_busybox_exec_path;
680 /* -s makes symlinks */
681 install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
685 if (strcmp(argv[1], "--help") == 0) {
686 /* "busybox --help [<applet>]" */
689 /* convert to "<applet> --help" */
693 /* "busybox <applet> arg1 arg2 ..." */
696 /* We support "busybox /a/path/to/applet args..." too. Allows for
697 * "#!/bin/busybox"-style wrappers */
698 applet_name = bb_get_last_path_component_nostrip(argv[0]);
699 run_applet_and_exit(applet_name, argv);
701 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
702 full_write2_str(applet_name);
703 full_write2_str(": applet not found\n");
707 void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
714 /* Reinit some shared global data */
715 xfunc_error_retval = EXIT_FAILURE;
717 applet_name = APPLET_NAME(applet_no);
718 if (argc == 2 && !strcmp(argv[1], "--help"))
720 if (ENABLE_FEATURE_SUID)
721 check_suid(applet_no);
722 exit(applet_main[applet_no](argc, argv));
725 void FAST_FUNC run_applet_and_exit(const char *name, char **argv)
727 int applet = find_applet_by_name(name);
729 run_applet_no_and_exit(applet, argv);
730 if (!strncmp(name, "busybox", 7))
731 exit(busybox_main(argv));
734 #endif /* !defined(SINGLE_APPLET_MAIN) */
738 #if ENABLE_BUILD_LIBBUSYBOX
739 int lbb_main(char **argv)
741 int main(int argc UNUSED_PARAM, char **argv)
744 #if defined(SINGLE_APPLET_MAIN)
745 /* Only one applet is selected by the user! */
746 /* applet_names in this case is just "applet\0\0" */
747 lbb_prepare(applet_names USE_FEATURE_INDIVIDUAL(, argv));
748 return SINGLE_APPLET_MAIN(argc, argv);
750 lbb_prepare("busybox" USE_FEATURE_INDIVIDUAL(, argv));
753 /* NOMMU re-exec trick sets high-order bit in first byte of name */
754 if (argv[0][0] & 0x80) {
759 applet_name = argv[0];
760 if (applet_name[0] == '-')
762 applet_name = bb_basename(applet_name);
764 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
766 run_applet_and_exit(applet_name, argv);
768 /*bb_error_msg_and_die("applet not found"); - sucks in printf */
769 full_write2_str(applet_name);
770 full_write2_str(": applet not found\n");