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(struct BB_applet) - 1;
52 const struct BB_applet *current_applet;
53 const char *applet_name ATTRIBUTE_EXTERNALLY_VISIBLE;
60 #if ENABLE_FEATURE_SUID_CONFIG
62 /* applets[] is const, so we have to define this "override" structure */
63 static struct BB_suid_config {
64 const struct BB_applet *m_applet;
68 struct BB_suid_config *m_next;
71 static smallint suid_cfg_readable;
73 /* check if u is member of group g */
74 static int ingroup(uid_t u, gid_t g)
76 struct group *grp = getgrgid(g);
81 for (mem = grp->gr_mem; *mem; mem++) {
82 struct passwd *pwd = getpwnam(*mem);
84 if (pwd && (pwd->pw_uid == u))
91 /* This should probably be a libbb routine. In that case,
92 * I'd probably rename it to something like bb_trimmed_slice.
94 static char *get_trimmed_slice(char *s, char *e)
96 /* First, consider the value at e to be nul and back up until we
97 * reach a non-space char. Set the char after that (possibly at
98 * the original e) to nul. */
106 /* Next, advance past all leading space and return a ptr to the
107 * first non-space char; possibly the terminating nul. */
108 return skip_whitespace(s);
111 /* Don't depend on the tools to combine strings. */
112 static const char config_file[] = "/etc/busybox.conf";
114 /* There are 4 chars + 1 nul for each of user/group/other. */
115 static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
117 /* We don't supply a value for the nul, so an index adjustment is
118 * necessary below. Also, we use unsigned short here to save some
119 * space even though these are really mode_t values. */
120 static const unsigned short mode_mask[] = {
121 /* SST sst xxx --- */
122 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
123 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
124 0, S_IXOTH, S_IXOTH, 0 /* other */
127 #define parse_error(x) do { errmsg = x; goto pe_label; } while(0)
129 static void parse_config_file(void)
131 struct BB_suid_config *sct_head;
132 struct BB_suid_config *sct;
133 const struct BB_applet *applet;
142 assert(!suid_config); /* Should be set to NULL by bss init. */
144 if ((stat(config_file, &st) != 0) /* No config file? */
145 || !S_ISREG(st.st_mode) /* Not a regular file? */
146 || (st.st_uid != 0) /* Not owned by root? */
147 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
148 || !(f = fopen(config_file, "r")) /* Cannot open? */
153 suid_cfg_readable = 1;
160 if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
161 if (ferror(f)) { /* Make sure it wasn't a read error. */
162 parse_error("reading");
165 suid_config = sct_head; /* Success, so set the pointer. */
169 lc++; /* Got a (partial) line. */
171 /* If a line is too long for our buffer, we consider it an error.
172 * The following test does mistreat one corner case though.
173 * If the final line of the file does not end with a newline and
174 * yet exactly fills the buffer, it will be treated as too long
175 * even though there isn't really a problem. But it isn't really
176 * worth adding code to deal with such an unlikely situation, and
177 * we do err on the side of caution. Besides, the line would be
178 * too long if it did end with a newline. */
179 if (!strchr(s, '\n') && !feof(f)) {
180 parse_error("line too long");
183 /* Trim leading and trailing whitespace, ignoring comments, and
184 * check if the resulting string is empty. */
185 s = get_trimmed_slice(s, strchrnul(s, '#'));
190 /* Check for a section header. */
193 /* Unlike the old code, we ignore leading and trailing
194 * whitespace for the section name. We also require that
195 * there are no stray characters after the closing bracket. */
197 if (!e /* Missing right bracket? */
198 || e[1] /* Trailing characters? */
199 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
201 parse_error("section header");
203 /* Right now we only have one section so just check it.
204 * If more sections are added in the future, please don't
205 * resort to cascading ifs with multiple strcasecmp calls.
206 * That kind of bloated code is all too common. A loop
207 * and a string table would be a better choice unless the
208 * number of sections is very small. */
209 if (strcasecmp(s, "SUID") == 0) {
213 section = -1; /* Unknown section so set to skip. */
217 /* Process sections. */
219 if (section == 1) { /* SUID */
220 /* Since we trimmed leading and trailing space above, we're
221 * now looking for strings of the form
222 * <key>[::space::]*=[::space::]*<value>
223 * where both key and value could contain inner whitespace. */
225 /* First get the key (an applet name in our case). */
228 s = get_trimmed_slice(s, e);
230 if (!e || !*s) { /* Missing '=' or empty key. */
231 parse_error("keyword");
234 /* Ok, we have an applet name. Process the rhs if this
235 * applet is currently built in and ignore it otherwise.
236 * Note: this can hide config file bugs which only pop
237 * up when the busybox configuration is changed. */
238 applet = find_applet_by_name(s);
240 /* Note: We currently don't check for duplicates!
241 * The last config line for each applet will be the
242 * one used since we insert at the head of the list.
243 * I suppose this could be considered a feature. */
244 sct = xmalloc(sizeof(struct BB_suid_config));
245 sct->m_applet = applet;
247 sct->m_next = sct_head;
250 /* Get the specified mode. */
252 e = skip_whitespace(e+1);
254 for (i = 0; i < 3; i++) {
256 q = strchrnul(mode_chars + 5*i, *e++);
260 /* Adjust by -i to account for nul. */
261 sct->m_mode |= mode_mask[(q - mode_chars) - i];
264 /* Now get the the user/group info. */
266 s = skip_whitespace(e);
268 /* Note: we require whitespace between the mode and the
269 * user/group info. */
270 if ((s == e) || !(e = strchr(s, '.'))) {
271 parse_error("<uid>.<gid>");
275 /* We can't use get_ug_id here since it would exit()
276 * if a uid or gid was not found. Oh well... */
277 sct->m_uid = bb_strtoul(s, NULL, 10);
279 struct passwd *pwd = getpwnam(s);
283 sct->m_uid = pwd->pw_uid;
286 sct->m_gid = bb_strtoul(e, NULL, 10);
291 parse_error("group");
293 sct->m_gid = grp->gr_gid;
299 /* Unknown sections are ignored. */
301 /* Encountering configuration lines prior to seeing a
302 * section header is treated as an error. This is how
303 * the old code worked, but it may not be desirable.
304 * We may want to simply ignore such lines in case they
305 * are used in some future version of busybox. */
307 parse_error("keyword outside section");
313 fprintf(stderr, "Parse error in %s, line %d: %s\n",
314 config_file, lc, errmsg);
317 /* Release any allocated memory before returning. */
319 sct = sct_head->m_next;
325 #define parse_config_file() ((void)0)
326 #endif /* FEATURE_SUID_CONFIG */
329 #if ENABLE_FEATURE_SUID
330 static void check_suid(const struct BB_applet *applet)
332 uid_t ruid = getuid(); /* real [ug]id */
333 uid_t rgid = getgid();
335 #if ENABLE_FEATURE_SUID_CONFIG
336 if (suid_cfg_readable) {
337 struct BB_suid_config *sct;
340 for (sct = suid_config; sct; sct = sct->m_next) {
341 if (sct->m_applet == applet)
344 /* default: drop all privileges */
350 if (sct->m_uid == ruid)
353 else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
354 /* same group / in group */
357 if (!(m & S_IXOTH)) /* is x bit not set ? */
358 bb_error_msg_and_die("you have no permission to run this applet!");
360 if (sct->m_gid != 0) {
361 /* _both_ have to be set for sgid */
362 if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
364 } else xsetgid(rgid); /* no sgid -> drop */
366 if (sct->m_uid != 0) {
367 if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
368 else xsetuid(ruid); /* no suid -> drop */
372 #if !ENABLE_FEATURE_SUID_CONFIG_QUIET
374 static smallint onetime = 0;
378 fprintf(stderr, "Using fallback suid method\n");
384 if (applet->need_suid == _BB_SUID_ALWAYS) {
386 bb_error_msg_and_die("applet requires root privileges!");
387 } else if (applet->need_suid == _BB_SUID_NEVER) {
388 xsetgid(rgid); /* drop all privileges */
393 #define check_suid(x) ((void)0)
394 #endif /* FEATURE_SUID */
397 #if ENABLE_FEATURE_COMPRESS_USAGE
399 #include "usage_compressed.h"
400 #include "unarchive.h"
402 static const char *unpack_usage_messages(void)
404 int input[2], output[2], pid;
407 if (pipe(input) < 0 || pipe(output) < 0)
410 //TODO: not NOMMU friendly!
418 uncompressStream(input[0], output[1]);
430 full_write(input[1], packed_usage, sizeof(packed_usage));
436 buf = xmalloc(SIZEOF_usage_messages);
437 full_read(output[0], buf, SIZEOF_usage_messages);
441 #define unpack_usage_messages() usage_messages
442 #endif /* FEATURE_COMPRESS_USAGE */
445 void bb_show_usage(void)
447 if (ENABLE_SHOW_USAGE) {
448 const char *format_string;
449 const char *usage_string = unpack_usage_messages();
452 i = current_applet - applets;
454 while (*usage_string++) continue;
458 format_string = "%s\n\nUsage: %s %s\n\n";
459 if (*usage_string == '\b')
460 format_string = "%s\n\nNo help available.\n\n";
461 fprintf(stderr, format_string, bb_msg_full_version,
462 applet_name, usage_string);
465 exit(xfunc_error_retval);
469 static int applet_name_compare(const void *name, const void *vapplet)
471 const struct BB_applet *applet = vapplet;
473 return strcmp(name, applet->name);
476 const struct BB_applet *find_applet_by_name(const char *name)
478 /* Do a binary search to find the applet entry given the name. */
479 return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
480 applet_name_compare);
484 #if ENABLE_FEATURE_INSTALLER
487 * this should be consistent w/ the enum, busybox.h::Location,
490 static const char usr_bin [] = "/usr/bin";
491 static const char usr_sbin[] = "/usr/sbin";
493 static const char *const install_dir[] = {
494 &usr_bin [8], /* "", equivalent to "/" for concat_path_file() */
495 &usr_bin [4], /* "/bin" */
496 &usr_sbin[4], /* "/sbin" */
501 /* create (sym)links for each applet */
502 static void install_links(const char *busybox, int use_symbolic_links)
504 int (*lf)(const char *, const char *) = link;
509 if (use_symbolic_links)
512 for (i = 0; applets[i].name != NULL; i++) {
513 fpc = concat_path_file(
514 install_dir[applets[i].location],
516 rc = lf(busybox, fpc);
517 if (rc != 0 && errno != EEXIST) {
518 bb_perror_msg("%s", fpc);
524 #define install_links(x,y) ((void)0)
525 #endif /* FEATURE_INSTALLER */
528 /* If we were called as "busybox..." */
529 static int busybox_main(int argc, char **argv)
531 if (ENABLE_FEATURE_INSTALLER && argc > 1 && !strcmp(argv[1], "--install")) {
532 int use_symbolic_links = 0;
535 /* to use symlinks, or not to use symlinks... */
537 if (strcmp(argv[2], "-s") == 0)
538 use_symbolic_links = 1;
541 busybox = xmalloc_readlink_or_warn("/proc/self/exe");
544 install_links(busybox, use_symbolic_links);
545 if (ENABLE_FEATURE_CLEAN_UP)
550 /* Deal with --help. Also print help when called with no arguments */
552 if (argc == 1 || !strcmp(argv[1], "--help") ) {
554 /* set name for proper "<name>: applet not found" */
555 applet_name = argv[2];
556 run_applet_by_name(applet_name, 2, 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) {
594 } else run_applet_by_name(argv[1], argc - 1, argv + 1);
596 bb_error_msg_and_die("applet not found");
599 void run_current_applet_and_exit(int argc, char **argv)
601 applet_name = current_applet->name;
602 if (argc == 2 && !strcmp(argv[1], "--help"))
604 if (ENABLE_FEATURE_SUID)
605 check_suid(current_applet);
606 exit(current_applet->main(argc, argv));
609 void run_applet_by_name(const char *name, int argc, char **argv)
611 current_applet = find_applet_by_name(name);
613 run_current_applet_and_exit(argc, argv);
614 if (!strncmp(name, "busybox", 7))
615 exit(busybox_main(argc, argv));
619 int main(int argc, char **argv)
623 applet_name = argv[0];
625 /* NOMMU re-exec trick sets high-order bit in first byte of name */
626 if (applet_name[0] & 0x80) {
628 applet_name[0] &= 0x7f;
631 if (applet_name[0] == '-')
633 s = strrchr(applet_name, '/');
637 if (ENABLE_FEATURE_SUID_CONFIG)
640 /* Set locale for everybody except 'init' */
641 if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
642 setlocale(LC_ALL, "");
644 run_applet_by_name(applet_name, argc, argv);
645 bb_error_msg_and_die("applet not found");