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.
19 /* Declare <applet>_main() */
24 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
25 /* Define usage_messages[] */
26 static const char usage_messages[] ALIGN1 = ""
33 #define usage_messages 0
34 #endif /* SHOW_USAGE */
37 /* Include generated applet names, pointers to <applet>_main, etc */
38 #include "applet_tables.h"
41 #if ENABLE_FEATURE_COMPRESS_USAGE
43 #include "usage_compressed.h"
44 #include "unarchive.h"
46 static const char *unpack_usage_messages(void)
54 /* inbuf: */ packed_usage,
55 /* len: */ sizeof(packed_usage));
56 /* read_bunzip can longjmp to start_bunzip, and ultimately
57 * end up here with i != 0 on read data errors! Not trivial */
59 /* Cannot use xmalloc: will leak bd in NOFORK case! */
60 outbuf = malloc_or_warn(SIZEOF_usage_messages);
62 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
67 #define dealloc_usage_messages(s) free(s)
71 #define unpack_usage_messages() usage_messages
72 #define dealloc_usage_messages(s) ((void)(s))
74 #endif /* FEATURE_COMPRESS_USAGE */
77 void bb_show_usage(void)
79 if (ENABLE_SHOW_USAGE) {
80 const char *format_string;
82 const char *usage_string = p = unpack_usage_messages();
83 int ap = find_applet_by_name(applet_name);
85 if (ap < 0) /* never happens, paranoia */
89 while (*p++) continue;
93 fprintf(stderr, "%s multi-call binary\n", bb_banner);
94 format_string = "\nUsage: %s %s\n\n";
96 format_string = "\nNo help available.\n\n";
97 fprintf(stderr, format_string, applet_name, p);
98 dealloc_usage_messages((char*)usage_string);
104 /* NB: any char pointer will work as well, not necessarily applet_names */
105 static int applet_name_compare(const void *name, const void *v)
107 int i = (const char *)v - applet_names;
108 return strcmp(name, APPLET_NAME(i));
110 int find_applet_by_name(const char *name)
112 /* Do a binary search to find the applet entry given the name. */
114 p = bsearch(name, applet_names, ARRAY_SIZE(applet_main), 1, applet_name_compare);
117 return p - applet_names;
122 /* Make it reside in R/W memory: */
123 int *const bb_errno __attribute__ ((section (".data")));
126 void lbb_prepare(const char *applet, char **argv)
129 (*(int **)&bb_errno) = __errno_location();
132 applet_name = applet;
134 /* Set locale for everybody except 'init' */
135 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
136 setlocale(LC_ALL, "");
138 #if ENABLE_FEATURE_INDIVIDUAL
139 /* Redundant for busybox (run_applet_and_exit covers that case)
140 * but needed for "individual applet" mode */
141 if (argv[1] && strcmp(argv[1], "--help") == 0)
146 /* The code below can well be in applets/applets.c, as it is used only
147 * for busybox binary, not "individual" binaries.
148 * However, keeping it here and linking it into libbusybox.so
149 * (together with remaining tiny applets/applets.o)
150 * makes it possible to avoid --whole-archive at link time.
151 * This makes (shared busybox) + libbusybox smaller.
152 * (--gc-sections would be even better....)
155 const char *applet_name;
160 USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
162 #if ENABLE_FEATURE_SUID_CONFIG
164 /* applets[] is const, so we have to define this "override" structure */
165 static struct BB_suid_config {
170 struct BB_suid_config *m_next;
173 static bool suid_cfg_readable;
175 /* check if u is member of group g */
176 static int ingroup(uid_t u, gid_t g)
178 struct group *grp = getgrgid(g);
183 for (mem = grp->gr_mem; *mem; mem++) {
184 struct passwd *pwd = getpwnam(*mem);
186 if (pwd && (pwd->pw_uid == u))
193 /* This should probably be a libbb routine. In that case,
194 * I'd probably rename it to something like bb_trimmed_slice.
196 static char *get_trimmed_slice(char *s, char *e)
198 /* First, consider the value at e to be nul and back up until we
199 * reach a non-space char. Set the char after that (possibly at
200 * the original e) to nul. */
208 /* Next, advance past all leading space and return a ptr to the
209 * first non-space char; possibly the terminating nul. */
210 return skip_whitespace(s);
213 /* Don't depend on the tools to combine strings. */
214 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
216 /* We don't supply a value for the nul, so an index adjustment is
217 * necessary below. Also, we use unsigned short here to save some
218 * space even though these are really mode_t values. */
219 static const unsigned short mode_mask[] ALIGN2 = {
220 /* SST sst xxx --- */
221 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
222 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
223 0, S_IXOTH, S_IXOTH, 0 /* other */
226 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
228 static void parse_config_file(void)
230 struct BB_suid_config *sct_head;
231 struct BB_suid_config *sct;
243 assert(!suid_config); /* Should be set to NULL by bss init. */
246 if (ruid == 0) /* run by root - don't need to even read config file */
249 if ((stat(config_file, &st) != 0) /* No config file? */
250 || !S_ISREG(st.st_mode) /* Not a regular file? */
251 || (st.st_uid != 0) /* Not owned by root? */
252 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
253 || !(f = fopen(config_file, "r")) /* Cannot open? */
258 suid_cfg_readable = 1;
265 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
266 if (ferror(f)) { /* Make sure it wasn't a read error. */
267 parse_error("reading");
270 suid_config = sct_head; /* Success, so set the pointer. */
274 lc++; /* Got a (partial) line. */
276 /* If a line is too long for our buffer, we consider it an error.
277 * The following test does mistreat one corner case though.
278 * If the final line of the file does not end with a newline and
279 * yet exactly fills the buffer, it will be treated as too long
280 * even though there isn't really a problem. But it isn't really
281 * worth adding code to deal with such an unlikely situation, and
282 * we do err on the side of caution. Besides, the line would be
283 * too long if it did end with a newline. */
284 if (!strchr(s, '\n') && !feof(f)) {
285 parse_error("line too long");
288 /* Trim leading and trailing whitespace, ignoring comments, and
289 * check if the resulting string is empty. */
290 s = get_trimmed_slice(s, strchrnul(s, '#'));
295 /* Check for a section header. */
298 /* Unlike the old code, we ignore leading and trailing
299 * whitespace for the section name. We also require that
300 * there are no stray characters after the closing bracket. */
302 if (!e /* Missing right bracket? */
303 || e[1] /* Trailing characters? */
304 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
306 parse_error("section header");
308 /* Right now we only have one section so just check it.
309 * If more sections are added in the future, please don't
310 * resort to cascading ifs with multiple strcasecmp calls.
311 * That kind of bloated code is all too common. A loop
312 * and a string table would be a better choice unless the
313 * number of sections is very small. */
314 if (strcasecmp(s, "SUID") == 0) {
318 section = -1; /* Unknown section so set to skip. */
322 /* Process sections. */
324 if (section == 1) { /* SUID */
325 /* Since we trimmed leading and trailing space above, we're
326 * now looking for strings of the form
327 * <key>[::space::]*=[::space::]*<value>
328 * where both key and value could contain inner whitespace. */
330 /* First get the key (an applet name in our case). */
333 s = get_trimmed_slice(s, e);
335 if (!e || !*s) { /* Missing '=' or empty key. */
336 parse_error("keyword");
339 /* Ok, we have an applet name. Process the rhs if this
340 * applet is currently built in and ignore it otherwise.
341 * Note: this can hide config file bugs which only pop
342 * up when the busybox configuration is changed. */
343 applet_no = find_applet_by_name(s);
344 if (applet_no >= 0) {
345 /* Note: We currently don't check for duplicates!
346 * The last config line for each applet will be the
347 * one used since we insert at the head of the list.
348 * I suppose this could be considered a feature. */
349 sct = xmalloc(sizeof(struct BB_suid_config));
350 sct->m_applet = applet_no;
352 sct->m_next = sct_head;
355 /* Get the specified mode. */
357 e = skip_whitespace(e+1);
359 for (i = 0; i < 3; i++) {
360 /* There are 4 chars + 1 nul for each of user/group/other. */
361 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
364 q = strchrnul(mode_chars + 5*i, *e++);
368 /* Adjust by -i to account for nul. */
369 sct->m_mode |= mode_mask[(q - mode_chars) - i];
372 /* Now get the the user/group info. */
374 s = skip_whitespace(e);
376 /* Note: we require whitespace between the mode and the
377 * user/group info. */
378 if ((s == e) || !(e = strchr(s, '.'))) {
379 parse_error("<uid>.<gid>");
383 /* We can't use get_ug_id here since it would exit()
384 * if a uid or gid was not found. Oh well... */
385 sct->m_uid = bb_strtoul(s, NULL, 10);
387 struct passwd *pwd = getpwnam(s);
391 sct->m_uid = pwd->pw_uid;
394 sct->m_gid = bb_strtoul(e, NULL, 10);
399 parse_error("group");
401 sct->m_gid = grp->gr_gid;
407 /* Unknown sections are ignored. */
409 /* Encountering configuration lines prior to seeing a
410 * section header is treated as an error. This is how
411 * the old code worked, but it may not be desirable.
412 * We may want to simply ignore such lines in case they
413 * are used in some future version of busybox. */
415 parse_error("keyword outside section");
421 fprintf(stderr, "Parse error in %s, line %d: %s\n",
422 config_file, lc, errmsg);
425 /* Release any allocated memory before returning. */
427 sct = sct_head->m_next;
433 static inline void parse_config_file(void)
435 USE_FEATURE_SUID(ruid = getuid();)
437 #endif /* FEATURE_SUID_CONFIG */
440 #if ENABLE_FEATURE_SUID
441 static void check_suid(int applet_no)
443 gid_t rgid; /* real gid */
445 if (ruid == 0) /* set by parse_config_file() */
446 return; /* run by root - no need to check more */
449 #if ENABLE_FEATURE_SUID_CONFIG
450 if (suid_cfg_readable) {
452 struct BB_suid_config *sct;
455 for (sct = suid_config; sct; sct = sct->m_next) {
456 if (sct->m_applet == applet_no)
459 goto check_need_suid;
462 if (sct->m_uid == ruid)
465 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
466 /* same group / in group */
469 if (!(m & S_IXOTH)) /* is x bit not set ? */
470 bb_error_msg_and_die("you have no permission to run this applet!");
472 /* _both_ sgid and group_exec have to be set for setegid */
473 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
475 /* else (no setegid) we will set egid = rgid */
477 /* We set effective AND saved ids. If saved-id is not set
478 * like we do below, seteiud(0) can still later succeed! */
479 if (setresgid(-1, rgid, rgid))
480 bb_perror_msg_and_die("setresgid");
482 /* do we have to set effective uid? */
484 if (sct->m_mode & S_ISUID)
486 /* else (no seteuid) we will set euid = ruid */
488 if (setresuid(-1, uid, uid))
489 bb_perror_msg_and_die("setresuid");
492 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
494 static bool onetime = 0;
498 fprintf(stderr, "Using fallback suid method\n");
504 if (APPLET_SUID(applet_no) == _BB_SUID_ALWAYS) {
505 /* Real uid is not 0. If euid isn't 0 too, suid bit
506 * is most probably not set on our executable */
508 bb_error_msg_and_die("must be suid to work properly");
509 } else if (APPLET_SUID(applet_no) == _BB_SUID_NEVER) {
510 xsetgid(rgid); /* drop all privileges */
515 #define check_suid(x) ((void)0)
516 #endif /* FEATURE_SUID */
519 #if ENABLE_FEATURE_INSTALLER
520 /* create (sym)links for each applet */
521 static void install_links(const char *busybox, int use_symbolic_links)
524 * this should be consistent w/ the enum,
525 * busybox.h::bb_install_loc_t, or else... */
526 static const char usr_bin [] ALIGN1 = "/usr/bin";
527 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
528 static const char *const install_dir[] = {
529 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
530 &usr_bin [4], /* "/bin" */
531 &usr_sbin[4], /* "/sbin" */
536 int (*lf)(const char *, const char *);
542 if (use_symbolic_links)
545 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
546 fpc = concat_path_file(
547 install_dir[APPLET_INSTALL_LOC(i)],
549 // debug: bb_error_msg("%slinking %s to busybox",
550 // use_symbolic_links ? "sym" : "", fpc);
551 rc = lf(busybox, fpc);
552 if (rc != 0 && errno != EEXIST) {
553 bb_simple_perror_msg(fpc);
559 #define install_links(x,y) ((void)0)
560 #endif /* FEATURE_INSTALLER */
562 /* If we were called as "busybox..." */
563 static int busybox_main(char **argv)
566 /* Called without arguments */
568 int col, output_width;
571 if (ENABLE_FEATURE_AUTOWIDTH) {
572 /* Obtain the terminal width */
573 get_terminal_width_height(0, &output_width, NULL);
575 /* leading tab and room to wrap */
576 output_width -= sizeof("start-stop-daemon, ") + 8;
578 printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
579 printf("Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n"
580 "and others. Licensed under GPLv2.\n"
581 "See source distribution for full notice.\n"
583 "Usage: busybox [function] [arguments]...\n"
584 " or: function [arguments]...\n"
586 "\tBusyBox is a multi-call binary that combines many common Unix\n"
587 "\tutilities into a single executable. Most people will create a\n"
588 "\tlink to busybox for each function they wish to use and BusyBox\n"
589 "\twill act like whatever it was invoked as!\n"
591 "Currently defined functions:\n");
595 if (col > output_width) {
599 col += printf("%s%s", (col ? ", " : "\t"), a);
606 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
608 busybox = xmalloc_readlink(bb_busybox_exec_path);
610 busybox = bb_busybox_exec_path;
611 /* -s makes symlinks */
612 install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
616 if (strcmp(argv[1], "--help") == 0) {
617 /* "busybox --help [<applet>]" */
620 /* convert to "<applet> --help" */
624 /* "busybox <applet> arg1 arg2 ..." */
627 /* We support "busybox /a/path/to/applet args..." too. Allows for
628 * "#!/bin/busybox"-style wrappers */
629 applet_name = bb_get_last_path_component_nostrip(argv[0]);
630 run_applet_and_exit(applet_name, argv);
631 bb_error_msg_and_die("applet not found");
634 void run_applet_no_and_exit(int applet_no, char **argv)
641 /* Reinit some shared global data */
642 xfunc_error_retval = EXIT_FAILURE;
644 applet_name = APPLET_NAME(applet_no);
645 if (argc == 2 && !strcmp(argv[1], "--help"))
647 if (ENABLE_FEATURE_SUID)
648 check_suid(applet_no);
649 exit(applet_main[applet_no](argc, argv));
652 void run_applet_and_exit(const char *name, char **argv)
654 int applet = find_applet_by_name(name);
656 run_applet_no_and_exit(applet, argv);
657 if (!strncmp(name, "busybox", 7))
658 exit(busybox_main(argv));
662 #if ENABLE_BUILD_LIBBUSYBOX
663 int lbb_main(int argc, char **argv)
665 int main(int argc, char **argv)
668 lbb_prepare("busybox", argv);
671 /* NOMMU re-exec trick sets high-order bit in first byte of name */
672 if (argv[0][0] & 0x80) {
677 applet_name = argv[0];
678 if (applet_name[0] == '-')
680 applet_name = bb_basename(applet_name);
682 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
684 run_applet_and_exit(applet_name, argv);
685 bb_error_msg_and_die("applet not found");