1 /* vi: set sw=4 ts=4: */
2 /*
3 * Utility routines.
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.
8 *
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 GPL.
11 *
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 */
14 /* We are trying to not use printf, this benefits the case when selected
15 * applets are really simple. Example:
16 *
17 * $ ./busybox
18 * ...
19 * Currently defined functions:
20 * basename, false, true
21 *
22 * $ size busybox
23 * text data bss dec hex filename
24 * 4473 52 72 4597 11f5 busybox
25 *
26 * FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
27 */
28
29 /* Define this accessor before we #define "errno" our way */
30 #include <errno.h>
get_perrno(void)31 static inline int *get_perrno(void) { return &errno; }
32
33 #include "busybox.h"
34
35 #if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
36 || defined(__APPLE__) \
37 )
38 # include <malloc.h> /* for mallopt */
39 #endif
40
41 /* Declare <applet>_main() */
42 #define PROTOTYPES
43 #include "applets.h"
44 #undef PROTOTYPES
45
46 /* Include generated applet names, pointers to <applet>_main, etc */
47 #include "applet_tables.h"
48 /* ...and if applet_tables generator says we have only one applet... */
49 #ifdef SINGLE_APPLET_MAIN
50 # undef ENABLE_FEATURE_INDIVIDUAL
51 # define ENABLE_FEATURE_INDIVIDUAL 1
52 # undef IF_FEATURE_INDIVIDUAL
53 # define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
54 #endif
55
56 #include "usage_compressed.h"
57
58 #if ENABLE_FEATURE_SH_EMBEDDED_SCRIPTS
59 # define DEFINE_SCRIPT_DATA 1
60 # include "embedded_scripts.h"
61 #else
62 # define NUM_SCRIPTS 0
63 #endif
64 #if NUM_SCRIPTS > 0
65 # include "bb_archive.h"
66 static const char packed_scripts[] ALIGN1 = { PACKED_SCRIPTS };
67 #endif
68
69 /* "Do not compress usage text if uncompressed text is small
70 * and we don't include bunzip2 code for other reasons"
71 *
72 * Useful for mass one-applet rebuild (bunzip2 code is ~2.7k).
73 *
74 * Unlike BUNZIP2, if FEATURE_SEAMLESS_BZ2 is on, bunzip2 code is built but
75 * still may be unused if none of the selected applets calls open_zipped()
76 * or its friends; we test for (FEATURE_SEAMLESS_BZ2 && <APPLET>) instead.
77 * For example, only if TAR and FEATURE_SEAMLESS_BZ2 are both selected,
78 * then bunzip2 code will be linked in anyway, and disabling help compression
79 * would be not optimal:
80 */
81 #if UNPACKED_USAGE_LENGTH < 4*1024 \
82 && !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_TAR) \
83 && !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_MODPROBE) \
84 && !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_INSMOD) \
85 && !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_DEPMOD) \
86 && !(ENABLE_FEATURE_SEAMLESS_BZ2 && ENABLE_MAN) \
87 && !ENABLE_BUNZIP2 \
88 && !ENABLE_BZCAT
89 # undef ENABLE_FEATURE_COMPRESS_USAGE
90 # define ENABLE_FEATURE_COMPRESS_USAGE 0
91 #endif
92
93
string_array_len(char ** argv)94 unsigned FAST_FUNC string_array_len(char **argv)
95 {
96 char **start = argv;
97
98 while (*argv)
99 argv++;
100
101 return argv - start;
102 }
103
104
105 #if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
106 static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
107 #else
108 # define usage_messages 0
109 #endif
110
111 #if ENABLE_FEATURE_COMPRESS_USAGE
112
113 static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
114 # include "bb_archive.h"
115 # define unpack_usage_messages() \
116 unpack_bz2_data(packed_usage, sizeof(packed_usage), sizeof(UNPACKED_USAGE))
117 # define dealloc_usage_messages(s) free(s)
118
119 #else
120
121 # define unpack_usage_messages() usage_messages
122 # define dealloc_usage_messages(s) ((void)(s))
123
124 #endif /* FEATURE_COMPRESS_USAGE */
125
126
bb_show_usage(void)127 void FAST_FUNC bb_show_usage(void)
128 {
129 if (ENABLE_SHOW_USAGE) {
130 #ifdef SINGLE_APPLET_STR
131 /* Imagine that this applet is "true". Dont link in printf! */
132 const char *usage_string = unpack_usage_messages();
133
134 if (usage_string) {
135 if (*usage_string == '\b') {
136 full_write2_str("No help available\n");
137 } else {
138 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
139 full_write2_str(usage_string);
140 full_write2_str("\n");
141 }
142 if (ENABLE_FEATURE_CLEAN_UP)
143 dealloc_usage_messages((char*)usage_string);
144 }
145 #else
146 const char *p;
147 const char *usage_string = p = unpack_usage_messages();
148 int ap = find_applet_by_name(applet_name);
149
150 if (ap < 0 || usage_string == NULL)
151 xfunc_die();
152 while (ap) {
153 while (*p++) continue;
154 ap--;
155 }
156 full_write2_str(bb_banner);
157 full_write2_str(" multi-call binary.\n"); /* common string */
158 if (*p == '\b')
159 full_write2_str("\nNo help available\n");
160 else {
161 full_write2_str("\nUsage: ");
162 full_write2_str(applet_name);
163 if (p[0]) {
164 if (p[0] != '\n')
165 full_write2_str(" ");
166 full_write2_str(p);
167 }
168 full_write2_str("\n");
169 }
170 if (ENABLE_FEATURE_CLEAN_UP)
171 dealloc_usage_messages((char*)usage_string);
172 #endif
173 }
174 xfunc_die();
175 }
176
find_applet_by_name(const char * name)177 int FAST_FUNC find_applet_by_name(const char *name)
178 {
179 unsigned i;
180 int j;
181 const char *p;
182
183 /* The commented-out word-at-a-time code is ~40% faster, but +160 bytes.
184 * "Faster" here saves ~0.5 microsecond of real time - not worth it.
185 */
186 #if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
187 uint32_t n32;
188
189 /* Handle all names < 2 chars long early */
190 if (name[0] == '\0')
191 return -1; /* "" is not a valid applet name */
192 if (name[1] == '\0') {
193 if (!ENABLE_TEST)
194 return -1; /* 1-char name is not valid */
195 if (name[0] != ']')
196 return -1; /* 1-char name which isn't "[" is not valid */
197 /* applet "[" is always applet #0: */
198 return 0;
199 }
200 #endif
201
202 p = applet_names;
203 #if KNOWN_APPNAME_OFFSETS <= 0
204 i = 0;
205 #else
206 i = NUM_APPLETS * (KNOWN_APPNAME_OFFSETS - 1);
207 for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
208 const char *pp = applet_names + applet_nameofs[j];
209 if (strcmp(name, pp) >= 0) {
210 //bb_error_msg("name:'%s' >= pp:'%s'", name, pp);
211 p = pp;
212 break;
213 }
214 i -= NUM_APPLETS;
215 }
216 i /= (unsigned)KNOWN_APPNAME_OFFSETS;
217 //bb_error_msg("name:'%s' starting from:'%s' i:%u", name, p, i);
218 #endif
219
220 /* Open-coded linear search without strcmp/strlen calls for speed */
221 while (*p) {
222 /* Do we see "name\0" at current position in applet_names? */
223 for (j = 0; *p == name[j]; ++j) {
224 if (*p++ == '\0') {
225 //bb_error_msg("found:'%s' i:%u", name, i);
226 return i; /* yes */
227 }
228 }
229 /* No. Have we gone too far, alphabetically? */
230 if (*p > name[j]) {
231 //bb_error_msg("break:'%s' i:%u", name, i);
232 break;
233 }
234 /* No. Move to the start of the next applet name. */
235 while (*p++ != '\0')
236 continue;
237 i++;
238 }
239 return -1;
240 }
241
242
243 void lbb_prepare(const char *applet
244 IF_FEATURE_INDIVIDUAL(, char **argv))
245 MAIN_EXTERNALLY_VISIBLE;
lbb_prepare(const char * applet IF_FEATURE_INDIVIDUAL (,char ** argv))246 void lbb_prepare(const char *applet
247 IF_FEATURE_INDIVIDUAL(, char **argv))
248 {
249 #ifdef bb_cached_errno_ptr
250 ASSIGN_CONST_PTR(&bb_errno, get_perrno());
251 #endif
252 applet_name = applet;
253
254 if (ENABLE_LOCALE_SUPPORT)
255 setlocale(LC_ALL, "");
256
257 #if ENABLE_FEATURE_INDIVIDUAL
258 /* Redundant for busybox (run_applet_and_exit covers that case)
259 * but needed for "individual applet" mode */
260 if (argv[1]
261 && !argv[2]
262 && strcmp(argv[1], "--help") == 0
263 && !is_prefixed_with(applet, "busybox")
264 ) {
265 /* Special cases. POSIX says "test --help"
266 * should be no different from e.g. "test --foo".
267 */
268 if (!(ENABLE_TEST && strcmp(applet_name, "test") == 0)
269 && !(ENABLE_TRUE && strcmp(applet_name, "true") == 0)
270 && !(ENABLE_FALSE && strcmp(applet_name, "false") == 0)
271 && !(ENABLE_ECHO && strcmp(applet_name, "echo") == 0)
272 )
273 bb_show_usage();
274 }
275 #endif
276 }
277
278 /* The code below can well be in applets/applets.c, as it is used only
279 * for busybox binary, not "individual" binaries.
280 * However, keeping it here and linking it into libbusybox.so
281 * (together with remaining tiny applets/applets.o)
282 * makes it possible to avoid --whole-archive at link time.
283 * This makes (shared busybox) + libbusybox smaller.
284 * (--gc-sections would be even better....)
285 */
286
287 const char *applet_name;
288 #if !BB_MMU
289 bool re_execed;
290 #endif
291
292
293 /* If not built as a single-applet executable... */
294 #if !defined(SINGLE_APPLET_MAIN)
295
296 IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
297
298 # if ENABLE_FEATURE_SUID_CONFIG
299
300 static struct suid_config_t {
301 /* next ptr must be first: this struct needs to be llist-compatible */
302 struct suid_config_t *m_next;
303 struct bb_uidgid_t m_ugid;
304 int m_applet;
305 mode_t m_mode;
306 } *suid_config;
307
308 static bool suid_cfg_readable;
309
310 /* libbb candidate */
get_trimmed_slice(char * s,char * e)311 static char *get_trimmed_slice(char *s, char *e)
312 {
313 /* First, consider the value at e to be nul and back up until we
314 * reach a non-space char. Set the char after that (possibly at
315 * the original e) to nul. */
316 while (e-- > s) {
317 if (!isspace(*e)) {
318 break;
319 }
320 }
321 e[1] = '\0';
322
323 /* Next, advance past all leading space and return a ptr to the
324 * first non-space char; possibly the terminating nul. */
325 return skip_whitespace(s);
326 }
327
parse_config_file(void)328 static void parse_config_file(void)
329 {
330 /* Don't depend on the tools to combine strings. */
331 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
332
333 struct suid_config_t *sct_head;
334 int applet_no;
335 FILE *f;
336 const char *errmsg;
337 unsigned lc;
338 smallint section;
339 struct stat st;
340
341 ruid = getuid();
342 if (ruid == 0) /* run by root - don't need to even read config file */
343 return;
344
345 if ((stat(config_file, &st) != 0) /* No config file? */
346 || !S_ISREG(st.st_mode) /* Not a regular file? */
347 || (st.st_uid != 0) /* Not owned by root? */
348 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
349 || !(f = fopen_for_read(config_file)) /* Cannot open? */
350 ) {
351 return;
352 }
353
354 suid_cfg_readable = 1;
355 sct_head = NULL;
356 section = lc = 0;
357
358 while (1) {
359 char buffer[256];
360 char *s;
361
362 if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
363 // Looks like bloat
364 //if (ferror(f)) { /* Make sure it wasn't a read error. */
365 // errmsg = "reading";
366 // goto pe_label;
367 //}
368 fclose(f);
369 suid_config = sct_head; /* Success, so set the pointer. */
370 return;
371 }
372
373 s = buffer;
374 lc++; /* Got a (partial) line. */
375
376 /* If a line is too long for our buffer, we consider it an error.
377 * The following test does mistreat one corner case though.
378 * If the final line of the file does not end with a newline and
379 * yet exactly fills the buffer, it will be treated as too long
380 * even though there isn't really a problem. But it isn't really
381 * worth adding code to deal with such an unlikely situation, and
382 * we do err on the side of caution. Besides, the line would be
383 * too long if it did end with a newline. */
384 if (!strchr(s, '\n') && !feof(f)) {
385 errmsg = "line too long";
386 goto pe_label;
387 }
388
389 /* Trim leading and trailing whitespace, ignoring comments, and
390 * check if the resulting string is empty. */
391 s = get_trimmed_slice(s, strchrnul(s, '#'));
392 if (!*s) {
393 continue;
394 }
395
396 /* Check for a section header. */
397
398 if (*s == '[') {
399 /* Unlike the old code, we ignore leading and trailing
400 * whitespace for the section name. We also require that
401 * there are no stray characters after the closing bracket. */
402 char *e = strchr(s, ']');
403 if (!e /* Missing right bracket? */
404 || e[1] /* Trailing characters? */
405 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
406 ) {
407 errmsg = "section header";
408 goto pe_label;
409 }
410 /* Right now we only have one section so just check it.
411 * If more sections are added in the future, please don't
412 * resort to cascading ifs with multiple strcasecmp calls.
413 * That kind of bloated code is all too common. A loop
414 * and a string table would be a better choice unless the
415 * number of sections is very small. */
416 if (strcasecmp(s, "SUID") == 0) {
417 section = 1;
418 continue;
419 }
420 section = -1; /* Unknown section so set to skip. */
421 continue;
422 }
423
424 /* Process sections. */
425
426 if (section == 1) { /* SUID */
427 /* Since we trimmed leading and trailing space above, we're
428 * now looking for strings of the form
429 * <key>[::space::]*=[::space::]*<value>
430 * where both key and value could contain inner whitespace. */
431
432 /* First get the key (an applet name in our case). */
433 char *e = strchr(s, '=');
434 if (e) {
435 s = get_trimmed_slice(s, e);
436 }
437 if (!e || !*s) { /* Missing '=' or empty key. */
438 errmsg = "keyword";
439 goto pe_label;
440 }
441
442 /* Ok, we have an applet name. Process the rhs if this
443 * applet is currently built in and ignore it otherwise.
444 * Note: this can hide config file bugs which only pop
445 * up when the busybox configuration is changed. */
446 applet_no = find_applet_by_name(s);
447 if (applet_no >= 0) {
448 unsigned i;
449 struct suid_config_t *sct;
450
451 /* Note: We currently don't check for duplicates!
452 * The last config line for each applet will be the
453 * one used since we insert at the head of the list.
454 * I suppose this could be considered a feature. */
455 sct = xzalloc(sizeof(*sct));
456 sct->m_applet = applet_no;
457 /*sct->m_mode = 0;*/
458 sct->m_next = sct_head;
459 sct_head = sct;
460
461 /* Get the specified mode. */
462
463 e = skip_whitespace(e+1);
464
465 for (i = 0; i < 3; i++) {
466 /* There are 4 chars for each of user/group/other.
467 * "x-xx" instead of "x-" are to make
468 * "idx > 3" check catch invalid chars.
469 */
470 static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
471 static const unsigned short mode_mask[] ALIGN2 = {
472 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
473 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
474 S_IXOTH, 0 /* x- */
475 };
476 const char *q = strchrnul(mode_chars + 4*i, *e);
477 unsigned idx = q - (mode_chars + 4*i);
478 if (idx > 3) {
479 errmsg = "mode";
480 goto pe_label;
481 }
482 sct->m_mode |= mode_mask[q - mode_chars];
483 e++;
484 }
485
486 /* Now get the user/group info. */
487
488 s = skip_whitespace(e);
489 /* Default is 0.0, else parse USER.GROUP: */
490 if (*s) {
491 /* We require whitespace between mode and USER.GROUP */
492 if ((s == e) || !(e = strchr(s, '.'))) {
493 errmsg = "uid.gid";
494 goto pe_label;
495 }
496 *e = ':'; /* get_uidgid needs USER:GROUP syntax */
497 if (get_uidgid(&sct->m_ugid, s) == 0) {
498 errmsg = "unknown user/group";
499 goto pe_label;
500 }
501 }
502 }
503 continue;
504 }
505
506 /* Unknown sections are ignored. */
507
508 /* Encountering configuration lines prior to seeing a
509 * section header is treated as an error. This is how
510 * the old code worked, but it may not be desirable.
511 * We may want to simply ignore such lines in case they
512 * are used in some future version of busybox. */
513 if (!section) {
514 errmsg = "keyword outside section";
515 goto pe_label;
516 }
517 } /* while (1) */
518
519 pe_label:
520 fclose(f);
521 bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
522
523 /* Release any allocated memory before returning. */
524 llist_free((llist_t*)sct_head, NULL);
525 }
526 # else
527 static inline void parse_config_file(void)
528 {
529 IF_FEATURE_SUID(ruid = getuid();)
530 }
531 # endif /* FEATURE_SUID_CONFIG */
532
533
534 # if ENABLE_FEATURE_SUID && NUM_APPLETS > 0
535 # if ENABLE_FEATURE_SUID_CONFIG
536 /* check if u is member of group g */
ingroup(uid_t u,gid_t g)537 static int ingroup(uid_t u, gid_t g)
538 {
539 struct group *grp = getgrgid(g);
540 if (grp) {
541 char **mem;
542 for (mem = grp->gr_mem; *mem; mem++) {
543 struct passwd *pwd = getpwnam(*mem);
544 if (pwd && (pwd->pw_uid == u))
545 return 1;
546 }
547 }
548 return 0;
549 }
550 # endif
551
check_suid(int applet_no)552 static void check_suid(int applet_no)
553 {
554 gid_t rgid; /* real gid */
555
556 if (ruid == 0) /* set by parse_config_file() */
557 return; /* run by root - no need to check more */
558 rgid = getgid();
559
560 # if ENABLE_FEATURE_SUID_CONFIG
561 if (suid_cfg_readable) {
562 uid_t uid;
563 struct suid_config_t *sct;
564 mode_t m;
565
566 for (sct = suid_config; sct; sct = sct->m_next) {
567 if (sct->m_applet == applet_no)
568 goto found;
569 }
570 goto check_need_suid;
571 found:
572 /* Is this user allowed to run this applet? */
573 m = sct->m_mode;
574 if (sct->m_ugid.uid == ruid)
575 /* same uid */
576 m >>= 6;
577 else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
578 /* same group / in group */
579 m >>= 3;
580 if (!(m & S_IXOTH)) /* is x bit not set? */
581 bb_simple_error_msg_and_die("you have no permission to run this applet");
582
583 /* We set effective AND saved ids. If saved-id is not set
584 * like we do below, seteuid(0) can still later succeed! */
585
586 /* Are we directed to change gid
587 * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
588 */
589 if (sct->m_mode & S_ISGID)
590 rgid = sct->m_ugid.gid;
591 /* else: we will set egid = rgid, thus dropping sgid effect */
592 if (setresgid(-1, rgid, rgid))
593 bb_simple_perror_msg_and_die("setresgid");
594
595 /* Are we directed to change uid
596 * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
597 */
598 uid = ruid;
599 if (sct->m_mode & S_ISUID)
600 uid = sct->m_ugid.uid;
601 /* else: we will set euid = ruid, thus dropping suid effect */
602 if (setresuid(-1, uid, uid))
603 bb_simple_perror_msg_and_die("setresuid");
604
605 goto ret;
606 }
607 # if !ENABLE_FEATURE_SUID_CONFIG_QUIET
608 {
609 static bool onetime = 0;
610
611 if (!onetime) {
612 onetime = 1;
613 bb_simple_error_msg("using fallback suid method");
614 }
615 }
616 # endif
617 check_need_suid:
618 # endif
619 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
620 /* Real uid is not 0. If euid isn't 0 too, suid bit
621 * is most probably not set on our executable */
622 if (geteuid())
623 bb_simple_error_msg_and_die("must be suid to work properly");
624 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
625 /*
626 * Drop all privileges.
627 *
628 * Don't check for errors: in normal use, they are impossible,
629 * and in special cases, exiting is harmful. Example:
630 * 'unshare --user' when user's shell is also from busybox.
631 *
632 * 'unshare --user' creates a new user namespace without any
633 * uid mappings. Thus, busybox binary is setuid nobody:nogroup
634 * within the namespace, as that is the only user. However,
635 * since no uids are mapped, calls to setgid/setuid
636 * fail (even though they would do nothing).
637 */
638 setgid(rgid);
639 setuid(ruid);
640 }
641 # if ENABLE_FEATURE_SUID_CONFIG
642 ret: ;
643 llist_free((llist_t*)suid_config, NULL);
644 # endif
645 }
646 # else
647 # define check_suid(x) ((void)0)
648 # endif /* FEATURE_SUID */
649
650
651 # if ENABLE_FEATURE_INSTALLER
652 static const char usr_bin [] ALIGN1 = "/usr/bin/";
653 static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
654 static const char *const install_dir[] = {
655 &usr_bin [8], /* "/" */
656 &usr_bin [4], /* "/bin/" */
657 &usr_sbin[4] /* "/sbin/" */
658 # if !ENABLE_INSTALL_NO_USR
659 ,usr_bin
660 ,usr_sbin
661 # endif
662 };
663
664 /* create (sym)links for each applet */
install_links(const char * busybox,int use_symbolic_links,char * custom_install_dir)665 static void install_links(const char *busybox, int use_symbolic_links,
666 char *custom_install_dir)
667 {
668 /* directory table
669 * this should be consistent w/ the enum,
670 * busybox.h::bb_install_loc_t, or else... */
671 int (*lf)(const char *, const char *);
672 char *fpc;
673 const char *appname = applet_names;
674 unsigned i;
675 int rc;
676
677 lf = link;
678 if (use_symbolic_links)
679 lf = symlink;
680
681 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
682 fpc = concat_path_file(
683 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
684 appname);
685 // debug: bb_error_msg("%slinking %s to busybox",
686 // use_symbolic_links ? "sym" : "", fpc);
687 rc = lf(busybox, fpc);
688 if (rc != 0 && errno != EEXIST) {
689 bb_simple_perror_msg(fpc);
690 }
691 free(fpc);
692 while (*appname++ != '\0')
693 continue;
694 }
695 }
696 # elif ENABLE_BUSYBOX
install_links(const char * busybox UNUSED_PARAM,int use_symbolic_links UNUSED_PARAM,char * custom_install_dir UNUSED_PARAM)697 static void install_links(const char *busybox UNUSED_PARAM,
698 int use_symbolic_links UNUSED_PARAM,
699 char *custom_install_dir UNUSED_PARAM)
700 {
701 }
702 # endif
703
704 # if ENABLE_BUSYBOX || NUM_APPLETS > 0
705 static void run_applet_and_exit(const char *name, char **argv) NORETURN;
706 #endif
707
708 # if NUM_SCRIPTS > 0
find_script_by_name(const char * name)709 static int find_script_by_name(const char *name)
710 {
711 int i;
712 int applet = find_applet_by_name(name);
713
714 if (applet >= 0) {
715 for (i = 0; i < NUM_SCRIPTS; ++i)
716 if (applet_numbers[i] == applet)
717 return i;
718 }
719 return -1;
720 }
721
722 int scripted_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
scripted_main(int argc UNUSED_PARAM,char ** argv)723 int scripted_main(int argc UNUSED_PARAM, char **argv)
724 {
725 int script = find_script_by_name(applet_name);
726 if (script >= 0)
727 # if ENABLE_SHELL_ASH
728 return ash_main(-script - 1, argv);
729 # elif ENABLE_SHELL_HUSH
730 return hush_main(-script - 1, argv);
731 # else
732 return 1;
733 # endif
734 return 0;
735 }
736
737 char* FAST_FUNC
get_script_content(unsigned n)738 get_script_content(unsigned n)
739 {
740 char *t = unpack_bz2_data(packed_scripts, sizeof(packed_scripts),
741 UNPACKED_SCRIPTS_LENGTH);
742 if (t) {
743 while (n != 0) {
744 while (*t++ != '\0')
745 continue;
746 n--;
747 }
748 }
749 return t;
750 }
751 # endif /* NUM_SCRIPTS > 0 */
752
753 # if ENABLE_BUSYBOX
754 # if ENABLE_FEATURE_SH_STANDALONE && ENABLE_FEATURE_TAB_COMPLETION
755 /*
756 * Insert "busybox" into applet table as well.
757 * This makes standalone shell tab-complete this name too.
758 * (Otherwise having "busybox" in applet table is not necessary,
759 * there is other code which routes "busyboxANY_SUFFIX" name
760 * to busybox_main()).
761 */
762 //usage:#define busybox_trivial_usage NOUSAGE_STR
763 //usage:#define busybox_full_usage ""
764 //applet:IF_BUSYBOX(IF_FEATURE_SH_STANDALONE(IF_FEATURE_TAB_COMPLETION(APPLET(busybox, BB_DIR_BIN, BB_SUID_MAYBE))))
765 int busybox_main(int argc, char *argv[]) MAIN_EXTERNALLY_VISIBLE;
766 # else
767 # define busybox_main(argc,argv) busybox_main(argv)
768 static
769 # endif
busybox_main(int argc UNUSED_PARAM,char ** argv)770 int busybox_main(int argc UNUSED_PARAM, char **argv)
771 {
772 if (!argv[1]) {
773 /* Called without arguments */
774 const char *a;
775 int col;
776 unsigned output_width;
777 help:
778 output_width = get_terminal_width(2);
779
780 dup2(1, 2);
781 full_write2_str(bb_banner); /* reuse const string */
782 full_write2_str(" multi-call binary.\n"); /* reuse */
783 full_write2_str(
784 "BusyBox is copyrighted by many authors between 1998-2015.\n"
785 "Licensed under GPLv2. See source distribution for detailed\n"
786 "copyright notices.\n"
787 "\n"
788 "Usage: busybox [function [arguments]...]\n"
789 " or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
790 # if ENABLE_FEATURE_SHOW_SCRIPT && NUM_SCRIPTS > 0
791 " or: busybox --show SCRIPT\n"
792 # endif
793 IF_FEATURE_INSTALLER(
794 " or: busybox --install [-s] [DIR]\n"
795 )
796 " or: function [arguments]...\n"
797 "\n"
798 IF_NOT_FEATURE_SH_STANDALONE(
799 "\tBusyBox is a multi-call binary that combines many common Unix\n"
800 "\tutilities into a single executable. Most people will create a\n"
801 "\tlink to busybox for each function they wish to use and BusyBox\n"
802 "\twill act like whatever it was invoked as.\n"
803 )
804 IF_FEATURE_SH_STANDALONE(
805 "\tBusyBox is a multi-call binary that combines many common Unix\n"
806 "\tutilities into a single executable. The shell in this build\n"
807 "\tis configured to run built-in utilities without $PATH search.\n"
808 "\tYou don't need to install a link to busybox for each utility.\n"
809 "\tTo run external program, use full path (/sbin/ip instead of ip).\n"
810 )
811 "\n"
812 "Currently defined functions:\n"
813 );
814 col = 0;
815 /* prevent last comma to be in the very last pos */
816 output_width--;
817 a = applet_names;
818 while (*a) {
819 int len2 = strlen(a) + 2;
820 if (col >= (int)output_width - len2) {
821 full_write2_str(",\n");
822 col = 0;
823 }
824 if (col == 0) {
825 col = 6;
826 full_write2_str("\t");
827 } else {
828 full_write2_str(", ");
829 }
830 full_write2_str(a);
831 col += len2;
832 a += len2 - 1;
833 }
834 full_write2_str("\n");
835 return 0;
836 }
837
838 # if ENABLE_FEATURE_SHOW_SCRIPT && NUM_SCRIPTS > 0
839 if (strcmp(argv[1], "--show") == 0) {
840 int n;
841 if (!argv[2])
842 bb_error_msg_and_die(bb_msg_requires_arg, "--show");
843 n = find_script_by_name(argv[2]);
844 if (n < 0)
845 bb_error_msg_and_die("script '%s' not found", argv[2]);
846 full_write1_str(get_script_content(n));
847 return 0;
848 }
849 # endif
850
851 if (is_prefixed_with(argv[1], "--list")) {
852 unsigned i = 0;
853 const char *a = applet_names;
854 dup2(1, 2);
855 while (*a) {
856 # if ENABLE_FEATURE_INSTALLER
857 if (argv[1][6]) /* --list-full? */
858 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
859 # endif
860 full_write2_str(a);
861 full_write2_str("\n");
862 i++;
863 while (*a++ != '\0')
864 continue;
865 }
866 return 0;
867 }
868
869 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
870 int use_symbolic_links;
871 const char *busybox;
872
873 busybox = xmalloc_readlink(bb_busybox_exec_path);
874 if (!busybox) {
875 /* bb_busybox_exec_path is usually "/proc/self/exe".
876 * In chroot, readlink("/proc/self/exe") usually fails.
877 * In such case, better use argv[0] as symlink target
878 * if it is a full path name.
879 */
880 if (argv[0][0] != '/')
881 bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
882 busybox = argv[0];
883 }
884 /* busybox --install [-s] [DIR]:
885 * -s: make symlinks
886 * DIR: directory to install links to
887 */
888 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
889 install_links(busybox, use_symbolic_links, argv[2]);
890 return 0;
891 }
892
893 if (strcmp(argv[1], "--help") == 0) {
894 /* "busybox --help [<applet>]" */
895 if (!argv[2]
896 # if ENABLE_FEATURE_SH_STANDALONE && ENABLE_FEATURE_TAB_COMPLETION
897 || strcmp(argv[2], "busybox") == 0 /* prevent getting "No help available" */
898 # endif
899 )
900 goto help;
901 /* convert to "<applet> --help" */
902 applet_name = argv[0] = argv[2];
903 argv[2] = NULL;
904 if (find_applet_by_name(applet_name) >= 0) {
905 /* Make "--help foo" exit with 0: */
906 xfunc_error_retval = 0;
907 bb_show_usage();
908 } /* else: unknown applet, fall through (causes "applet not found" later) */
909 } else {
910 /* "busybox <applet> arg1 arg2 ..." */
911 argv++;
912 /* We support "busybox /a/path/to/applet args..." too. Allows for
913 * "#!/bin/busybox"-style wrappers
914 */
915 applet_name = bb_get_last_path_component_nostrip(argv[0]);
916 }
917 run_applet_and_exit(applet_name, argv);
918 }
919 # endif
920
921 # if NUM_APPLETS > 0
show_usage_if_dash_dash_help(int applet_no,char ** argv)922 void FAST_FUNC show_usage_if_dash_dash_help(int applet_no, char **argv)
923 {
924 /* Special case. POSIX says "test --help"
925 * should be no different from e.g. "test --foo".
926 * Thus for "test", we skip --help check.
927 * "true", "false", "echo" are also special.
928 */
929 if (1
930 # if defined APPLET_NO_test
931 && applet_no != APPLET_NO_test
932 # endif
933 # if defined APPLET_NO_true
934 && applet_no != APPLET_NO_true
935 # endif
936 # if defined APPLET_NO_false
937 && applet_no != APPLET_NO_false
938 # endif
939 # if defined APPLET_NO_echo
940 && applet_no != APPLET_NO_echo
941 # endif
942 ) {
943 if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
944 /* Make "foo --help" exit with 0: */
945 xfunc_error_retval = 0;
946 bb_show_usage();
947 }
948 }
949 }
950
run_applet_no_and_exit(int applet_no,const char * name,char ** argv)951 void FAST_FUNC run_applet_no_and_exit(int applet_no, const char *name, char **argv)
952 {
953 int argc;
954
955 /*
956 * We do not use argv[0]: do not want to repeat massaging of
957 * "-/sbin/halt" -> "halt", for example.
958 */
959 applet_name = name;
960
961 show_usage_if_dash_dash_help(applet_no, argv);
962
963 if (ENABLE_FEATURE_SUID)
964 check_suid(applet_no);
965
966 argc = string_array_len(argv);
967 xfunc_error_retval = applet_main[applet_no](argc, argv);
968
969 /* Note: applet_main() may also not return (die on a xfunc or such) */
970 xfunc_die();
971 }
972 # endif /* NUM_APPLETS > 0 */
973
974 # if ENABLE_BUSYBOX || NUM_APPLETS > 0
run_applet_and_exit(const char * name,char ** argv)975 static NORETURN void run_applet_and_exit(const char *name, char **argv)
976 {
977 # if ENABLE_BUSYBOX
978 if (is_prefixed_with(name, "busybox"))
979 exit(busybox_main(/*unused:*/ 0, argv));
980 # endif
981 # if NUM_APPLETS > 0
982 /* find_applet_by_name() search is more expensive, so goes second */
983 {
984 int applet = find_applet_by_name(name);
985 if (applet >= 0)
986 run_applet_no_and_exit(applet, name, argv);
987 }
988 # endif
989
990 /*bb_error_msg_and_die("applet not found"); - links in printf */
991 full_write2_str(applet_name);
992 full_write2_str(": applet not found\n");
993 /* POSIX: "If a command is not found, the exit status shall be 127" */
994 exit(127);
995 }
996 # endif
997
998 #else /* defined(SINGLE_APPLET_MAIN) */
999
1000 # if NUM_SCRIPTS > 0
1001 /* if SINGLE_APPLET_MAIN, these two functions are simpler: */
1002 int scripted_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
scripted_main(int argc UNUSED_PARAM,char ** argv)1003 int scripted_main(int argc UNUSED_PARAM, char **argv)
1004 {
1005 # if ENABLE_SHELL_ASH
1006 int script = 0;
1007 return ash_main(-script - 1, argv);
1008 # elif ENABLE_SHELL_HUSH
1009 int script = 0;
1010 return hush_main(-script - 1, argv);
1011 # else
1012 return 1;
1013 # endif
1014 }
1015 char* FAST_FUNC
get_script_content(unsigned n UNUSED_PARAM)1016 get_script_content(unsigned n UNUSED_PARAM)
1017 {
1018 char *t = unpack_bz2_data(packed_scripts, sizeof(packed_scripts),
1019 UNPACKED_SCRIPTS_LENGTH);
1020 return t;
1021 }
1022 # endif /* NUM_SCRIPTS > 0 */
1023
1024 #endif /* defined(SINGLE_APPLET_MAIN) */
1025
1026
1027 #if ENABLE_BUILD_LIBBUSYBOX
lbb_main(char ** argv)1028 int lbb_main(char **argv)
1029 #else
1030 int main(int argc UNUSED_PARAM, char **argv)
1031 #endif
1032 {
1033 #if 0
1034 /* TODO: find a use for a block of memory between end of .bss
1035 * and end of page. For example, I'm getting "_end:0x812e698 2408 bytes"
1036 * - more than 2k of wasted memory (in this particular build)
1037 * *per each running process*!
1038 * (If your linker does not generate "_end" name, weak attribute
1039 * makes &_end == NULL, end_len == 0 here.)
1040 */
1041 extern char _end[] __attribute__((weak));
1042 unsigned end_len = (-(int)_end) & 0xfff;
1043 printf("_end:%p %u bytes\n", &_end, end_len);
1044 #endif
1045
1046 /* Tweak malloc for reduced memory consumption */
1047 #ifdef M_TRIM_THRESHOLD
1048 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
1049 * to keep before releasing to the OS
1050 * Default is way too big: 256k
1051 */
1052 mallopt(M_TRIM_THRESHOLD, 8 * 1024);
1053 #endif
1054 #ifdef M_MMAP_THRESHOLD
1055 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
1056 * Default is too big: 256k
1057 */
1058 mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
1059 #endif
1060 #if 0 /*def M_TOP_PAD*/
1061 /* When the program break is increased, then M_TOP_PAD bytes are added
1062 * to the sbrk(2) request. When the heap is trimmed because of free(3),
1063 * this much free space is preserved at the top of the heap.
1064 * glibc default seems to be way too big: 128k, but need to verify.
1065 */
1066 mallopt(M_TOP_PAD, 8 * 1024);
1067 #endif
1068
1069 #if !BB_MMU
1070 /* NOMMU re-exec trick sets high-order bit in first byte of name */
1071 if (argv[0][0] & 0x80) {
1072 re_execed = 1;
1073 argv[0][0] &= 0x7f;
1074 }
1075 #endif
1076
1077 #if defined(SINGLE_APPLET_MAIN)
1078
1079 /* Only one applet is selected in .config */
1080 if (argv[1] && is_prefixed_with(argv[0], "busybox")) {
1081 /* "busybox <applet> <params>" should still work as expected */
1082 argv++;
1083 }
1084 /* applet_names in this case is just "applet\0\0" */
1085 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
1086 # if ENABLE_BUILD_LIBBUSYBOX
1087 return SINGLE_APPLET_MAIN(string_array_len(argv), argv);
1088 # else
1089 return SINGLE_APPLET_MAIN(argc, argv);
1090 # endif
1091
1092 #elif !ENABLE_BUSYBOX && NUM_APPLETS == 0
1093
1094 full_write2_str(bb_basename(argv[0]));
1095 full_write2_str(": no applets enabled\n");
1096 return 127;
1097
1098 #else
1099
1100 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
1101 # if !ENABLE_BUSYBOX
1102 if (argv[1] && is_prefixed_with(bb_basename(argv[0]), "busybox"))
1103 argv++;
1104 # endif
1105 applet_name = argv[0];
1106 if (applet_name[0] == '-')
1107 applet_name++;
1108 applet_name = bb_basename(applet_name);
1109
1110 /* If we are a result of execv("/proc/self/exe"), fix ugly comm of "exe" */
1111 if (ENABLE_FEATURE_SH_STANDALONE
1112 || ENABLE_FEATURE_PREFER_APPLETS
1113 || !BB_MMU
1114 ) {
1115 if (NUM_APPLETS > 1) {
1116 /* Careful, do not trash comm of "SCRIPT.sh" -
1117 * the case when started from e.g. #!/bin/ash script.
1118 * (not limited to shells - #!/bin/awk scripts also exist)
1119 */
1120 if (re_execed_comm())
1121 set_task_comm(applet_name);
1122 }
1123 }
1124
1125 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
1126 run_applet_and_exit(applet_name, argv);
1127
1128 #endif
1129 }
1130