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
127 USE_FEATURE_INDIVIDUAL(, char **argv))
130 (*(int **)&bb_errno) = __errno_location();
133 applet_name = applet;
135 /* Set locale for everybody except 'init' */
136 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
137 setlocale(LC_ALL, "");
139 #if ENABLE_FEATURE_INDIVIDUAL
140 /* Redundant for busybox (run_applet_and_exit covers that case)
141 * but needed for "individual applet" mode */
142 if (argv[1] && strcmp(argv[1], "--help") == 0)
147 /* The code below can well be in applets/applets.c, as it is used only
148 * for busybox binary, not "individual" binaries.
149 * However, keeping it here and linking it into libbusybox.so
150 * (together with remaining tiny applets/applets.o)
151 * makes it possible to avoid --whole-archive at link time.
152 * This makes (shared busybox) + libbusybox smaller.
153 * (--gc-sections would be even better....)
156 const char *applet_name;
161 USE_FEATURE_SUID(static uid_t ruid;) /* real uid */
163 #if ENABLE_FEATURE_SUID_CONFIG
165 /* applets[] is const, so we have to define this "override" structure */
166 static struct BB_suid_config {
171 struct BB_suid_config *m_next;
174 static bool suid_cfg_readable;
176 /* check if u is member of group g */
177 static int ingroup(uid_t u, gid_t g)
179 struct group *grp = getgrgid(g);
184 for (mem = grp->gr_mem; *mem; mem++) {
185 struct passwd *pwd = getpwnam(*mem);
187 if (pwd && (pwd->pw_uid == u))
194 /* This should probably be a libbb routine. In that case,
195 * I'd probably rename it to something like bb_trimmed_slice.
197 static char *get_trimmed_slice(char *s, char *e)
199 /* First, consider the value at e to be nul and back up until we
200 * reach a non-space char. Set the char after that (possibly at
201 * the original e) to nul. */
209 /* Next, advance past all leading space and return a ptr to the
210 * first non-space char; possibly the terminating nul. */
211 return skip_whitespace(s);
214 /* Don't depend on the tools to combine strings. */
215 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
217 /* We don't supply a value for the nul, so an index adjustment is
218 * necessary below. Also, we use unsigned short here to save some
219 * space even though these are really mode_t values. */
220 static const unsigned short mode_mask[] ALIGN2 = {
221 /* SST sst xxx --- */
222 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
223 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
224 0, S_IXOTH, S_IXOTH, 0 /* other */
227 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
229 static void parse_config_file(void)
231 struct BB_suid_config *sct_head;
232 struct BB_suid_config *sct;
244 assert(!suid_config); /* Should be set to NULL by bss init. */
247 if (ruid == 0) /* run by root - don't need to even read config file */
250 if ((stat(config_file, &st) != 0) /* No config file? */
251 || !S_ISREG(st.st_mode) /* Not a regular file? */
252 || (st.st_uid != 0) /* Not owned by root? */
253 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
254 || !(f = fopen(config_file, "r")) /* Cannot open? */
259 suid_cfg_readable = 1;
266 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
268 if (ferror(f)) { /* Make sure it wasn't a read error. */
269 parse_error("reading");
272 suid_config = sct_head; /* Success, so set the pointer. */
276 lc++; /* Got a (partial) line. */
278 /* If a line is too long for our buffer, we consider it an error.
279 * The following test does mistreat one corner case though.
280 * If the final line of the file does not end with a newline and
281 * yet exactly fills the buffer, it will be treated as too long
282 * even though there isn't really a problem. But it isn't really
283 * worth adding code to deal with such an unlikely situation, and
284 * we do err on the side of caution. Besides, the line would be
285 * too long if it did end with a newline. */
286 if (!strchr(s, '\n') && !feof(f)) {
287 parse_error("line too long");
290 /* Trim leading and trailing whitespace, ignoring comments, and
291 * check if the resulting string is empty. */
292 s = get_trimmed_slice(s, strchrnul(s, '#'));
297 /* Check for a section header. */
300 /* Unlike the old code, we ignore leading and trailing
301 * whitespace for the section name. We also require that
302 * there are no stray characters after the closing bracket. */
304 if (!e /* Missing right bracket? */
305 || e[1] /* Trailing characters? */
306 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
308 parse_error("section header");
310 /* Right now we only have one section so just check it.
311 * If more sections are added in the future, please don't
312 * resort to cascading ifs with multiple strcasecmp calls.
313 * That kind of bloated code is all too common. A loop
314 * and a string table would be a better choice unless the
315 * number of sections is very small. */
316 if (strcasecmp(s, "SUID") == 0) {
320 section = -1; /* Unknown section so set to skip. */
324 /* Process sections. */
326 if (section == 1) { /* SUID */
327 /* Since we trimmed leading and trailing space above, we're
328 * now looking for strings of the form
329 * <key>[::space::]*=[::space::]*<value>
330 * where both key and value could contain inner whitespace. */
332 /* First get the key (an applet name in our case). */
335 s = get_trimmed_slice(s, e);
337 if (!e || !*s) { /* Missing '=' or empty key. */
338 parse_error("keyword");
341 /* Ok, we have an applet name. Process the rhs if this
342 * applet is currently built in and ignore it otherwise.
343 * Note: this can hide config file bugs which only pop
344 * up when the busybox configuration is changed. */
345 applet_no = find_applet_by_name(s);
346 if (applet_no >= 0) {
347 /* Note: We currently don't check for duplicates!
348 * The last config line for each applet will be the
349 * one used since we insert at the head of the list.
350 * I suppose this could be considered a feature. */
351 sct = xmalloc(sizeof(struct BB_suid_config));
352 sct->m_applet = applet_no;
354 sct->m_next = sct_head;
357 /* Get the specified mode. */
359 e = skip_whitespace(e+1);
361 for (i = 0; i < 3; i++) {
362 /* There are 4 chars + 1 nul for each of user/group/other. */
363 static const char mode_chars[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-";
366 q = strchrnul(mode_chars + 5*i, *e++);
370 /* Adjust by -i to account for nul. */
371 sct->m_mode |= mode_mask[(q - mode_chars) - i];
374 /* Now get the the user/group info. */
376 s = skip_whitespace(e);
378 /* Note: we require whitespace between the mode and the
379 * user/group info. */
380 if ((s == e) || !(e = strchr(s, '.'))) {
381 parse_error("<uid>.<gid>");
385 /* We can't use get_ug_id here since it would exit()
386 * if a uid or gid was not found. Oh well... */
387 sct->m_uid = bb_strtoul(s, NULL, 10);
389 struct passwd *pwd = getpwnam(s);
393 sct->m_uid = pwd->pw_uid;
396 sct->m_gid = bb_strtoul(e, NULL, 10);
401 parse_error("group");
403 sct->m_gid = grp->gr_gid;
409 /* Unknown sections are ignored. */
411 /* Encountering configuration lines prior to seeing a
412 * section header is treated as an error. This is how
413 * the old code worked, but it may not be desirable.
414 * We may want to simply ignore such lines in case they
415 * are used in some future version of busybox. */
417 parse_error("keyword outside section");
423 fprintf(stderr, "Parse error in %s, line %d: %s\n",
424 config_file, lc, errmsg);
427 /* Release any allocated memory before returning. */
429 sct = sct_head->m_next;
435 static inline void parse_config_file(void)
437 USE_FEATURE_SUID(ruid = getuid();)
439 #endif /* FEATURE_SUID_CONFIG */
442 #if ENABLE_FEATURE_SUID
443 static void check_suid(int applet_no)
445 gid_t rgid; /* real gid */
447 if (ruid == 0) /* set by parse_config_file() */
448 return; /* run by root - no need to check more */
451 #if ENABLE_FEATURE_SUID_CONFIG
452 if (suid_cfg_readable) {
454 struct BB_suid_config *sct;
457 for (sct = suid_config; sct; sct = sct->m_next) {
458 if (sct->m_applet == applet_no)
461 goto check_need_suid;
464 if (sct->m_uid == ruid)
467 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
468 /* same group / in group */
471 if (!(m & S_IXOTH)) /* is x bit not set ? */
472 bb_error_msg_and_die("you have no permission to run this applet!");
474 /* _both_ sgid and group_exec have to be set for setegid */
475 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
477 /* else (no setegid) we will set egid = rgid */
479 /* We set effective AND saved ids. If saved-id is not set
480 * like we do below, seteiud(0) can still later succeed! */
481 if (setresgid(-1, rgid, rgid))
482 bb_perror_msg_and_die("setresgid");
484 /* do we have to set effective uid? */
486 if (sct->m_mode & S_ISUID)
488 /* else (no seteuid) we will set euid = ruid */
490 if (setresuid(-1, uid, uid))
491 bb_perror_msg_and_die("setresuid");
494 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
496 static bool onetime = 0;
500 fprintf(stderr, "Using fallback suid method\n");
506 if (APPLET_SUID(applet_no) == _BB_SUID_ALWAYS) {
507 /* Real uid is not 0. If euid isn't 0 too, suid bit
508 * is most probably not set on our executable */
510 bb_error_msg_and_die("must be suid to work properly");
511 } else if (APPLET_SUID(applet_no) == _BB_SUID_NEVER) {
512 xsetgid(rgid); /* drop all privileges */
517 #define check_suid(x) ((void)0)
518 #endif /* FEATURE_SUID */
521 #if ENABLE_FEATURE_INSTALLER
522 /* create (sym)links for each applet */
523 static void install_links(const char *busybox, int use_symbolic_links)
526 * this should be consistent w/ the enum,
527 * busybox.h::bb_install_loc_t, or else... */
528 static const char usr_bin [] ALIGN1 = "/usr/bin";
529 static const char usr_sbin[] ALIGN1 = "/usr/sbin";
530 static const char *const install_dir[] = {
531 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
532 &usr_bin [4], /* "/bin" */
533 &usr_sbin[4], /* "/sbin" */
538 int (*lf)(const char *, const char *);
544 if (use_symbolic_links)
547 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
548 fpc = concat_path_file(
549 install_dir[APPLET_INSTALL_LOC(i)],
551 // debug: bb_error_msg("%slinking %s to busybox",
552 // use_symbolic_links ? "sym" : "", fpc);
553 rc = lf(busybox, fpc);
554 if (rc != 0 && errno != EEXIST) {
555 bb_simple_perror_msg(fpc);
561 #define install_links(x,y) ((void)0)
562 #endif /* FEATURE_INSTALLER */
564 /* If we were called as "busybox..." */
565 static int busybox_main(char **argv)
568 /* Called without arguments */
570 int col, output_width;
573 if (ENABLE_FEATURE_AUTOWIDTH) {
574 /* Obtain the terminal width */
575 get_terminal_width_height(0, &output_width, NULL);
577 /* leading tab and room to wrap */
578 output_width -= sizeof("start-stop-daemon, ") + 8;
580 printf("%s multi-call binary\n", bb_banner); /* reuse const string... */
581 printf("Copyright (C) 1998-2007 Erik Andersen, Rob Landley, Denys Vlasenko\n"
582 "and others. Licensed under GPLv2.\n"
583 "See source distribution for full notice.\n"
585 "Usage: busybox [function] [arguments]...\n"
586 " or: function [arguments]...\n"
588 "\tBusyBox is a multi-call binary that combines many common Unix\n"
589 "\tutilities into a single executable. Most people will create a\n"
590 "\tlink to busybox for each function they wish to use and BusyBox\n"
591 "\twill act like whatever it was invoked as!\n"
593 "Currently defined functions:\n");
597 if (col > output_width) {
601 col += printf("%s%s", (col ? ", " : "\t"), a);
608 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
610 busybox = xmalloc_readlink(bb_busybox_exec_path);
612 busybox = bb_busybox_exec_path;
613 /* -s makes symlinks */
614 install_links(busybox, argv[2] && strcmp(argv[2], "-s") == 0);
618 if (strcmp(argv[1], "--help") == 0) {
619 /* "busybox --help [<applet>]" */
622 /* convert to "<applet> --help" */
626 /* "busybox <applet> arg1 arg2 ..." */
629 /* We support "busybox /a/path/to/applet args..." too. Allows for
630 * "#!/bin/busybox"-style wrappers */
631 applet_name = bb_get_last_path_component_nostrip(argv[0]);
632 run_applet_and_exit(applet_name, argv);
633 bb_error_msg_and_die("applet not found");
636 void run_applet_no_and_exit(int applet_no, char **argv)
643 /* Reinit some shared global data */
644 xfunc_error_retval = EXIT_FAILURE;
646 applet_name = APPLET_NAME(applet_no);
647 if (argc == 2 && !strcmp(argv[1], "--help"))
649 if (ENABLE_FEATURE_SUID)
650 check_suid(applet_no);
651 exit(applet_main[applet_no](argc, argv));
654 void run_applet_and_exit(const char *name, char **argv)
656 int applet = find_applet_by_name(name);
658 run_applet_no_and_exit(applet, argv);
659 if (!strncmp(name, "busybox", 7))
660 exit(busybox_main(argv));
664 #if ENABLE_BUILD_LIBBUSYBOX
665 int lbb_main(char **argv)
667 int main(int argc ATTRIBUTE_UNUSED, char **argv)
670 lbb_prepare("busybox" USE_FEATURE_INDIVIDUAL(, argv));
673 /* NOMMU re-exec trick sets high-order bit in first byte of name */
674 if (argv[0][0] & 0x80) {
679 applet_name = argv[0];
680 if (applet_name[0] == '-')
682 applet_name = bb_basename(applet_name);
684 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
686 run_applet_and_exit(applet_name, argv);
687 bb_error_msg_and_die("applet not found");