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.
18 /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
19 #if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
20 #warning Static linking against glibc produces buggy executables
21 #warning (glibc does not cope well with ld --gc-sections).
22 #warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
23 #warning Note that glibc is unsuitable for static linking anyway.
24 #warning If you still want to do it, remove -Wl,--gc-sections
25 #warning from top-level Makefile and remove this warning.
29 /* Declare <applet>_main() */
34 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
35 /* Define usage_messages[] */
36 static const char usage_messages[] = ""
43 #define usage_messages 0
44 #endif /* SHOW_USAGE */
46 /* Define struct bb_applet applets[] */
48 /* The -1 arises because of the {0,NULL,0,-1} entry. */
49 const unsigned short NUM_APPLETS = sizeof(applets) / sizeof(applets[0]) - 1;
51 const struct bb_applet *current_applet;
52 const char *applet_name ATTRIBUTE_EXTERNALLY_VISIBLE;
57 #if ENABLE_FEATURE_SUID
58 static uid_t ruid; /* real uid */
61 #if ENABLE_FEATURE_SUID_CONFIG
63 /* applets[] is const, so we have to define this "override" structure */
64 static struct BB_suid_config {
65 const struct bb_applet *m_applet;
69 struct BB_suid_config *m_next;
72 static bool suid_cfg_readable;
74 /* check if u is member of group g */
75 static int ingroup(uid_t u, gid_t g)
77 struct group *grp = getgrgid(g);
82 for (mem = grp->gr_mem; *mem; mem++) {
83 struct passwd *pwd = getpwnam(*mem);
85 if (pwd && (pwd->pw_uid == u))
92 /* This should probably be a libbb routine. In that case,
93 * I'd probably rename it to something like bb_trimmed_slice.
95 static char *get_trimmed_slice(char *s, char *e)
97 /* First, consider the value at e to be nul and back up until we
98 * reach a non-space char. Set the char after that (possibly at
99 * the original e) to nul. */
107 /* Next, advance past all leading space and return a ptr to the
108 * first non-space char; possibly the terminating nul. */
109 return skip_whitespace(s);
112 /* Don't depend on the tools to combine strings. */
113 static const char config_file[] = "/etc/busybox.conf";
115 /* There are 4 chars + 1 nul for each of user/group/other. */
116 static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
118 /* We don't supply a value for the nul, so an index adjustment is
119 * necessary below. Also, we use unsigned short here to save some
120 * space even though these are really mode_t values. */
121 static const unsigned short mode_mask[] = {
122 /* SST sst xxx --- */
123 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
124 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
125 0, S_IXOTH, S_IXOTH, 0 /* other */
128 #define parse_error(x) do { errmsg = x; goto pe_label; } while (0)
130 static void parse_config_file(void)
132 struct BB_suid_config *sct_head;
133 struct BB_suid_config *sct;
134 const struct bb_applet *applet;
145 assert(!suid_config); /* Should be set to NULL by bss init. */
148 if (ruid == 0) /* run by root - don't need to even read config file */
151 if ((stat(config_file, &st) != 0) /* No config file? */
152 || !S_ISREG(st.st_mode) /* Not a regular file? */
153 || (st.st_uid != 0) /* Not owned by root? */
154 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
155 || !(f = fopen(config_file, "r")) /* Cannot open? */
160 suid_cfg_readable = 1;
167 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
168 if (ferror(f)) { /* Make sure it wasn't a read error. */
169 parse_error("reading");
172 suid_config = sct_head; /* Success, so set the pointer. */
176 lc++; /* Got a (partial) line. */
178 /* If a line is too long for our buffer, we consider it an error.
179 * The following test does mistreat one corner case though.
180 * If the final line of the file does not end with a newline and
181 * yet exactly fills the buffer, it will be treated as too long
182 * even though there isn't really a problem. But it isn't really
183 * worth adding code to deal with such an unlikely situation, and
184 * we do err on the side of caution. Besides, the line would be
185 * too long if it did end with a newline. */
186 if (!strchr(s, '\n') && !feof(f)) {
187 parse_error("line too long");
190 /* Trim leading and trailing whitespace, ignoring comments, and
191 * check if the resulting string is empty. */
192 s = get_trimmed_slice(s, strchrnul(s, '#'));
197 /* Check for a section header. */
200 /* Unlike the old code, we ignore leading and trailing
201 * whitespace for the section name. We also require that
202 * there are no stray characters after the closing bracket. */
204 if (!e /* Missing right bracket? */
205 || e[1] /* Trailing characters? */
206 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
208 parse_error("section header");
210 /* Right now we only have one section so just check it.
211 * If more sections are added in the future, please don't
212 * resort to cascading ifs with multiple strcasecmp calls.
213 * That kind of bloated code is all too common. A loop
214 * and a string table would be a better choice unless the
215 * number of sections is very small. */
216 if (strcasecmp(s, "SUID") == 0) {
220 section = -1; /* Unknown section so set to skip. */
224 /* Process sections. */
226 if (section == 1) { /* SUID */
227 /* Since we trimmed leading and trailing space above, we're
228 * now looking for strings of the form
229 * <key>[::space::]*=[::space::]*<value>
230 * where both key and value could contain inner whitespace. */
232 /* First get the key (an applet name in our case). */
235 s = get_trimmed_slice(s, e);
237 if (!e || !*s) { /* Missing '=' or empty key. */
238 parse_error("keyword");
241 /* Ok, we have an applet name. Process the rhs if this
242 * applet is currently built in and ignore it otherwise.
243 * Note: this can hide config file bugs which only pop
244 * up when the busybox configuration is changed. */
245 applet = find_applet_by_name(s);
247 /* Note: We currently don't check for duplicates!
248 * The last config line for each applet will be the
249 * one used since we insert at the head of the list.
250 * I suppose this could be considered a feature. */
251 sct = xmalloc(sizeof(struct BB_suid_config));
252 sct->m_applet = applet;
254 sct->m_next = sct_head;
257 /* Get the specified mode. */
259 e = skip_whitespace(e+1);
261 for (i = 0; i < 3; i++) {
263 q = strchrnul(mode_chars + 5*i, *e++);
267 /* Adjust by -i to account for nul. */
268 sct->m_mode |= mode_mask[(q - mode_chars) - i];
271 /* Now get the the user/group info. */
273 s = skip_whitespace(e);
275 /* Note: we require whitespace between the mode and the
276 * user/group info. */
277 if ((s == e) || !(e = strchr(s, '.'))) {
278 parse_error("<uid>.<gid>");
282 /* We can't use get_ug_id here since it would exit()
283 * if a uid or gid was not found. Oh well... */
284 sct->m_uid = bb_strtoul(s, NULL, 10);
286 struct passwd *pwd = getpwnam(s);
290 sct->m_uid = pwd->pw_uid;
293 sct->m_gid = bb_strtoul(e, NULL, 10);
298 parse_error("group");
300 sct->m_gid = grp->gr_gid;
306 /* Unknown sections are ignored. */
308 /* Encountering configuration lines prior to seeing a
309 * section header is treated as an error. This is how
310 * the old code worked, but it may not be desirable.
311 * We may want to simply ignore such lines in case they
312 * are used in some future version of busybox. */
314 parse_error("keyword outside section");
320 fprintf(stderr, "Parse error in %s, line %d: %s\n",
321 config_file, lc, errmsg);
324 /* Release any allocated memory before returning. */
326 sct = sct_head->m_next;
332 static inline void parse_config_file(void)
336 #endif /* FEATURE_SUID_CONFIG */
339 #if ENABLE_FEATURE_SUID
340 static void check_suid(const struct bb_applet *applet)
342 uid_t rgid; /* real gid */
344 if (ruid == 0) /* set by parse_config_file() */
345 return; /* run by root - no need to check more */
348 #if ENABLE_FEATURE_SUID_CONFIG
349 if (suid_cfg_readable) {
350 struct BB_suid_config *sct;
353 for (sct = suid_config; sct; sct = sct->m_next) {
354 if (sct->m_applet == applet)
357 /* default: drop all privileges */
363 if (sct->m_uid == ruid)
366 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
367 /* same group / in group */
370 if (!(m & S_IXOTH)) /* is x bit not set ? */
371 bb_error_msg_and_die("you have no permission to run this applet!");
373 if (sct->m_gid != 0) {
374 /* _both_ have to be set for sgid */
375 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
377 } else xsetgid(rgid); /* no sgid -> drop */
379 if (sct->m_uid != 0) {
380 if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
381 else xsetuid(ruid); /* no suid -> drop */
385 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
387 static bool onetime = 0;
391 fprintf(stderr, "Using fallback suid method\n");
397 if (applet->need_suid == _BB_SUID_ALWAYS) {
399 bb_error_msg_and_die("applet requires root privileges!");
400 } else if (applet->need_suid == _BB_SUID_NEVER) {
401 xsetgid(rgid); /* drop all privileges */
406 #define check_suid(x) ((void)0)
407 #endif /* FEATURE_SUID */
410 #if ENABLE_FEATURE_COMPRESS_USAGE
412 #include "usage_compressed.h"
413 #include "unarchive.h"
415 static const char *unpack_usage_messages(void)
421 i = start_bunzip(&bd,
423 /* inbuf: */ packed_usage,
424 /* len: */ sizeof(packed_usage));
425 /* read_bunzip can longjmp to start_bunzip, and ultimately
426 * end up here with i != 0 on read data errors! Not trivial */
428 /* Cannot use xmalloc: will leak bd in NOFORK case! */
429 outbuf = malloc_or_warn(SIZEOF_usage_messages);
431 read_bunzip(bd, outbuf, SIZEOF_usage_messages);
436 #define dealloc_usage_messages(s) free(s)
440 #define unpack_usage_messages() usage_messages
441 #define dealloc_usage_messages(s) ((void)(s))
443 #endif /* FEATURE_COMPRESS_USAGE */
446 void bb_show_usage(void)
448 if (ENABLE_SHOW_USAGE) {
449 const char *format_string;
451 const char *usage_string = p = unpack_usage_messages();
454 i = current_applet - applets;
456 while (*p++) continue;
460 format_string = "%s\n\nUsage: %s %s\n\n";
462 format_string = "%s\n\nNo help available.\n\n";
463 fprintf(stderr, format_string, bb_msg_full_version,
465 dealloc_usage_messages((char*)usage_string);
471 static int applet_name_compare(const void *name, const void *vapplet)
473 const struct bb_applet *applet = vapplet;
475 return strcmp(name, applet->name);
478 const struct bb_applet *find_applet_by_name(const char *name)
480 /* Do a binary search to find the applet entry given the name. */
481 return bsearch(name, applets, NUM_APPLETS, sizeof(applets[0]),
482 applet_name_compare);
486 #if ENABLE_FEATURE_INSTALLER
487 /* create (sym)links for each applet */
488 static void install_links(const char *busybox, int use_symbolic_links)
491 * this should be consistent w/ the enum,
492 * busybox.h::bb_install_loc_t, or else... */
493 static const char usr_bin [] = "/usr/bin";
494 static const char usr_sbin[] = "/usr/sbin";
495 static const char *const install_dir[] = {
496 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
497 &usr_bin [4], /* "/bin" */
498 &usr_sbin[4], /* "/sbin" */
503 int (*lf)(const char *, const char *) = link;
508 if (use_symbolic_links)
511 for (i = 0; applets[i].name != NULL; i++) {
512 fpc = concat_path_file(
513 install_dir[applets[i].install_loc],
515 rc = lf(busybox, fpc);
516 if (rc != 0 && errno != EEXIST) {
517 bb_perror_msg("%s", fpc);
523 #define install_links(x,y) ((void)0)
524 #endif /* FEATURE_INSTALLER */
527 /* If we were called as "busybox..." */
528 static int busybox_main(char **argv)
530 if (ENABLE_FEATURE_INSTALLER && argv[1] && !strcmp(argv[1], "--install")) {
531 int use_symbolic_links = 0;
534 /* to use symlinks, or not to use symlinks... */
536 if (strcmp(argv[2], "-s") == 0)
537 use_symbolic_links = 1;
540 busybox = xmalloc_readlink_or_warn("/proc/self/exe");
543 install_links(busybox, use_symbolic_links);
544 if (ENABLE_FEATURE_CLEAN_UP)
549 /* Deal with --help. Also print help when called with no arguments */
551 if (!argv[1] || !strcmp(argv[1], "--help") ) {
553 /* set name for proper "<name>: applet not found" */
554 applet_name = argv[2];
556 run_applet_and_exit(applet_name, argv);
558 const struct bb_applet *a;
559 int col, output_width;
561 output_width = 80 - sizeof("start-stop-daemon, ") - 8;
562 if (ENABLE_FEATURE_AUTOWIDTH) {
563 /* Obtain the terminal width. */
564 get_terminal_width_height(0, &output_width, NULL);
565 /* leading tab and room to wrap */
566 output_width -= sizeof("start-stop-daemon, ") + 8;
570 "Copyright (C) 1998-2006 Erik Andersen, Rob Landley, and others.\n"
571 "Licensed under GPLv2. See source distribution for full notice.\n"
573 "Usage: busybox [function] [arguments]...\n"
574 " or: [function] [arguments]...\n"
576 "\tBusyBox is a multi-call binary that combines many common Unix\n"
577 "\tutilities into a single executable. Most people will create a\n"
578 "\tlink to busybox for each function they wish to use and BusyBox\n"
579 "\twill act like whatever it was invoked as!\n"
580 "\nCurrently defined functions:\n", bb_msg_full_version);
584 col += printf("%s%s", (col ? ", " : "\t"), a->name);
586 if (col > output_width && a->name) {
595 /* we want "<argv[1]>: applet not found", not "busybox: ..." */
596 applet_name = argv[1];
597 run_applet_and_exit(argv[1], argv + 1);
600 bb_error_msg_and_die("applet not found");
603 void run_current_applet_and_exit(char **argv)
610 /* Reinit some shared global data */
612 xfunc_error_retval = EXIT_FAILURE;
614 applet_name = current_applet->name;
615 if (argc == 2 && !strcmp(argv[1], "--help"))
617 if (ENABLE_FEATURE_SUID)
618 check_suid(current_applet);
619 exit(current_applet->main(argc, argv));
622 void run_applet_and_exit(const char *name, char **argv)
624 current_applet = find_applet_by_name(name);
626 run_current_applet_and_exit(argv);
627 if (!strncmp(name, "busybox", 7))
628 exit(busybox_main(argv));
632 int main(int argc, char **argv)
637 /* NOMMU re-exec trick sets high-order bit in first byte of name */
638 if (argv[0][0] & 0x80) {
643 applet_name = argv[0];
644 if (applet_name[0] == '-')
646 s = strrchr(applet_name, '/');
650 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
652 /* Set locale for everybody except 'init' */
653 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
654 setlocale(LC_ALL, "");
656 run_applet_and_exit(applet_name, argv);
657 bb_error_msg_and_die("applet not found");