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 <apllet>_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();
131 applet_name = applet;
133 /* Set locale for everybody except 'init' */
134 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
135 setlocale(LC_ALL, "");
137 #if ENABLE_FEATURE_INDIVIDUAL
138 /* Redundant for busybox (run_applet_and_exit covers that case)
139 * but needed for "individual applet" mode */
140 if (argv[1] && strcmp(argv[1], "--help") == 0)
145 /* The code below can well be in applets/applets.c, as it is used only
146 * for busybox binary, not "individual" binaries.
147 * However, keeping it here and linking it into libbusybox.so
148 * (together with remaining tiny applets/applets.o)
149 * makes it possible to avoid --whole-archive at link time.
150 * This makes (shared busybox) + libbusybox smaller.
151 * (--gc-sections would be even better....)
154 const char *applet_name;
159 USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
161 #if ENABLE_FEATURE_SUID_CONFIG
163 /* applets[] is const, so we have to define this "override" structure */
164 static struct BB_suid_config {
169 struct BB_suid_config *m_next;
172 static bool suid_cfg_readable;
174 /* check if u is member of group g */
175 static int ingroup(uid_t u, gid_t g)
177 struct group *grp = getgrgid(g);
182 for (mem = grp->gr_mem; *mem; mem++) {
183 struct passwd *pwd = getpwnam(*mem);
185 if (pwd && (pwd->pw_uid == u))
192 /* This should probably be a libbb routine. In that case,
193 * I'd probably rename it to something like bb_trimmed_slice.
195 static char *get_trimmed_slice(char *s, char *e)
197 /* First, consider the value at e to be nul and back up until we
198 * reach a non-space char. Set the char after that (possibly at
199 * the original e) to nul. */
207 /* Next, advance past all leading space and return a ptr to the
208 * first non-space char; possibly the terminating nul. */
209 return skip_whitespace(s);
212 /* Don't depend on the tools to combine strings. */
213 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
215 /* We don't supply a value for the nul, so an index adjustment is
216 * necessary below. Also, we use unsigned short here to save some
217 * space even though these are really mode_t values. */
218 static const unsigned short mode_mask[] ALIGN2 = {
219 /* SST sst xxx --- */
220 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
221 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
222 0, S_IXOTH, S_IXOTH, 0 /* other */
225 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
227 static void parse_config_file(void)
229 struct BB_suid_config *sct_head;
230 struct BB_suid_config *sct;
242 assert(!suid_config); /* Should be set to NULL by bss init. */
245 if (ruid == 0) /* run by root - don't need to even read config file */
248 if ((stat(config_file, &st) != 0) /* No config file? */
249 || !S_ISREG(st.st_mode) /* Not a regular file? */
250 || (st.st_uid != 0) /* Not owned by root? */
251 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
252 || !(f = fopen(config_file, "r")) /* Cannot open? */
257 suid_cfg_readable = 1;
264 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
265 if (ferror(f)) { /* Make sure it wasn't a read error. */
266 parse_error("reading");
269 suid_config = sct_head; /* Success, so set the pointer. */
273 lc++; /* Got a (partial) line. */
275 /* If a line is too long for our buffer, we consider it an error.
276 * The following test does mistreat one corner case though.
277 * If the final line of the file does not end with a newline and
278 * yet exactly fills the buffer, it will be treated as too long
279 * even though there isn't really a problem. But it isn't really
280 * worth adding code to deal with such an unlikely situation, and
281 * we do err on the side of caution. Besides, the line would be
282 * too long if it did end with a newline. */
283 if (!strchr(s, '\n') && !feof(f)) {
284 parse_error("line too long");
287 /* Trim leading and trailing whitespace, ignoring comments, and
288 * check if the resulting string is empty. */
289 s = get_trimmed_slice(s, strchrnul(s, '#'));
294 /* Check for a section header. */
297 /* Unlike the old code, we ignore leading and trailing
298 * whitespace for the section name. We also require that
299 * there are no stray characters after the closing bracket. */
301 if (!e /* Missing right bracket? */
302 || e[1] /* Trailing characters? */
303 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
305 parse_error("section header");
307 /* Right now we only have one section so just check it.
308 * If more sections are added in the future, please don't
309 * resort to cascading ifs with multiple strcasecmp calls.
310 * That kind of bloated code is all too common. A loop
311 * and a string table would be a better choice unless the
312 * number of sections is very small. */
313 if (strcasecmp(s, "SUID") == 0) {
317 section = -1; /* Unknown section so set to skip. */
321 /* Process sections. */
323 if (section == 1) { /* SUID */
324 /* Since we trimmed leading and trailing space above, we're
325 * now looking for strings of the form
326 * <key>[::space::]*=[::space::]*<value>
327 * where both key and value could contain inner whitespace. */
329 /* First get the key (an applet name in our case). */
332 s = get_trimmed_slice(s, e);
334 if (!e || !*s) { /* Missing '=' or empty key. */
335 parse_error("keyword");
338 /* Ok, we have an applet name. Process the rhs if this
339 * applet is currently built in and ignore it otherwise.
340 * Note: this can hide config file bugs which only pop
341 * up when the busybox configuration is changed. */
342 applet_no = find_applet_by_name(s);
343 if (applet_no >= 0) {
344 /* Note: We currently don't check for duplicates!
345 * The last config line for each applet will be the
346 * one used since we insert at the head of the list.
347 * I suppose this could be considered a feature. */
348 sct = xmalloc(sizeof(struct BB_suid_config));
349 sct->m_applet = applet_no;
351 sct->m_next = sct_head;
354 /* Get the specified mode. */
356 e = skip_whitespace(e+1);
358 for (i = 0; i < 3; i++) {
359 /* There are 4 chars + 1 nul for each of user/group/other. */
360 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
363 q = strchrnul(mode_chars + 5*i, *e++);
367 /* Adjust by -i to account for nul. */
368 sct->m_mode |= mode_mask[(q - mode_chars) - i];
371 /* Now get the the user/group info. */
373 s = skip_whitespace(e);
375 /* Note: we require whitespace between the mode and the
376 * user/group info. */
377 if ((s == e) || !(e = strchr(s, '.'))) {
378 parse_error("<uid>.<gid>");
382 /* We can't use get_ug_id here since it would exit()
383 * if a uid or gid was not found. Oh well... */
384 sct->m_uid = bb_strtoul(s, NULL, 10);
386 struct passwd *pwd = getpwnam(s);
390 sct->m_uid = pwd->pw_uid;
393 sct->m_gid = bb_strtoul(e, NULL, 10);
398 parse_error("group");
400 sct->m_gid = grp->gr_gid;
406 /* Unknown sections are ignored. */
408 /* Encountering configuration lines prior to seeing a
409 * section header is treated as an error. This is how
410 * the old code worked, but it may not be desirable.
411 * We may want to simply ignore such lines in case they
412 * are used in some future version of busybox. */
414 parse_error("keyword outside section");
420 fprintf(stderr, "Parse error in %s, line %d: %s\n",
421 config_file, lc, errmsg);
424 /* Release any allocated memory before returning. */
426 sct = sct_head->m_next;
432 static inline void parse_config_file(void)
434 USE_FEATURE_SUID(ruid = getuid();)
436 #endif /* FEATURE_SUID_CONFIG */
439 #if ENABLE_FEATURE_SUID
440 static void check_suid(int applet_no)
442 gid_t rgid; /* real gid */
444 if (ruid == 0) /* set by parse_config_file() */
445 return; /* run by root - no need to check more */
448 #if ENABLE_FEATURE_SUID_CONFIG
449 if (suid_cfg_readable) {
451 struct BB_suid_config *sct;
454 for (sct = suid_config; sct; sct = sct->m_next) {
455 if (sct->m_applet == applet_no)
458 goto check_need_suid;
461 if (sct->m_uid == ruid)
464 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
465 /* same group / in group */
468 if (!(m & S_IXOTH)) /* is x bit not set ? */
469 bb_error_msg_and_die("you have no permission to run this applet!");
471 /* _both_ sgid and group_exec have to be set for setegid */
472 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
474 /* else (no setegid) we will set egid = rgid */
476 /* We set effective AND saved ids. If saved-id is not set
477 * like we do below, seteiud(0) can still later succeed! */
478 if (setresgid(-1, rgid, rgid))
479 bb_perror_msg_and_die("setresgid");
481 /* do we have to set effective uid? */
483 if (sct->m_mode & S_ISUID)
485 /* else (no seteuid) we will set euid = ruid */
487 if (setresuid(-1, uid, uid))
488 bb_perror_msg_and_die("setresuid");
491 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
493 static bool onetime = 0;
497 fprintf(stderr, "Using fallback suid method\n");
503 if (APPLET_SUID(applet_no) == _BB_SUID_ALWAYS) {
504 /* Real uid is not 0. If euid isn't 0 too, suid bit
505 * is most probably not set on our executable */
507 bb_error_msg_and_die("must be suid to work properly");
508 } else if (APPLET_SUID(applet_no) == _BB_SUID_NEVER) {
509 xsetgid(rgid); /* drop all privileges */
514 #define check_suid(x) ((void)0)
515 #endif /* FEATURE_SUID */
518 #if ENABLE_FEATURE_INSTALLER
519 /* create (sym)links for each applet */
520 static void install_links(const char *busybox, int use_symbolic_links)
523 * this should be consistent w/ the enum,
524 * busybox.h::bb_install_loc_t, or else... */
525 static const char usr_bin [] ALIGN1 = "/usr/bin";
526 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
527 static const char *const install_dir[] = {
528 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
529 &usr_bin [4], /* "/bin" */
530 &usr_sbin[4], /* "/sbin" */
535 int (*lf)(const char *, const char *);
541 if (use_symbolic_links)
544 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
545 fpc = concat_path_file(
546 install_dir[APPLET_INSTALL_LOC(i)],
548 // debug: bb_error_msg("%slinking %s to busybox",
549 // use_symbolic_links ? "sym" : "", fpc);
550 rc = lf(busybox, fpc);
551 if (rc != 0 && errno != EEXIST) {
552 bb_simple_perror_msg(fpc);
558 #define install_links(x,y) ((void)0)
559 #endif /* FEATURE_INSTALLER */
561 /* If we were called as "busybox..." */
562 static int busybox_main(char **argv)
565 /* Called without arguments */
567 int col, output_width;
570 if (ENABLE_FEATURE_AUTOWIDTH) {
571 /* Obtain the terminal width */
572 get_terminal_width_height(0, &output_width, NULL);
574 /* leading tab and room to wrap */
575 output_width -= sizeof("start-stop-daemon, ") + 8;
577 printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
578 printf("Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n"
579 "and others. Licensed under GPLv2.\n"
580 "See source distribution for full notice.\n"
582 "Usage: busybox [function] [arguments]...\n"
583 " or: function [arguments]...\n"
585 "\tBusyBox is a multi-call binary that combines many common Unix\n"
586 "\tutilities into a single executable. Most people will create a\n"
587 "\tlink to busybox for each function they wish to use and BusyBox\n"
588 "\twill act like whatever it was invoked as!\n"
590 "Currently defined functions:\n");
594 if (col > output_width) {
598 col += printf("%s%s", (col ? ", " : "\t"), a);
605 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
607 busybox = xmalloc_readlink(bb_busybox_exec_path);
609 busybox = bb_busybox_exec_path;
610 /* -s makes symlinks */
611 install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
615 if (strcmp(argv[1], "--help") == 0) {
616 /* "busybox --help [<applet>]" */
619 /* convert to "<applet> --help" */
623 /* "busybox <applet> arg1 arg2 ..." */
626 /* We support "busybox /a/path/to/applet args..." too. Allows for
627 * "#!/bin/busybox"-style wrappers */
628 applet_name = bb_get_last_path_component_nostrip(argv[0]);
629 run_applet_and_exit(applet_name, argv);
630 bb_error_msg_and_die("applet not found");
633 void run_applet_no_and_exit(int applet_no, char **argv)
640 /* 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");