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path: root/libbb/appletlib.c (plain)
blob: 9425c7bd4de05712b6e4f0edab641af76d5684f6
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
15/* We are trying to not use printf, this benefits the case when selected
16 * applets are really simple. Example:
17 *
18 * $ ./busybox
19 * ...
20 * Currently defined functions:
21 * basename, false, true
22 *
23 * $ size busybox
24 * text data bss dec hex filename
25 * 4473 52 72 4597 11f5 busybox
26 *
27 * FEATURE_INSTALLER or FEATURE_SUID will still link printf routines in. :(
28 */
29#include "busybox.h"
30
31#if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
32 || defined(__APPLE__) \
33 )
34# include <malloc.h> /* for mallopt */
35#endif
36
37
38/* Declare <applet>_main() */
39#define PROTOTYPES
40#include "applets.h"
41#undef PROTOTYPES
42
43/* Include generated applet names, pointers to <applet>_main, etc */
44#include "applet_tables.h"
45/* ...and if applet_tables generator says we have only one applet... */
46#ifdef SINGLE_APPLET_MAIN
47# undef ENABLE_FEATURE_INDIVIDUAL
48# define ENABLE_FEATURE_INDIVIDUAL 1
49# undef IF_FEATURE_INDIVIDUAL
50# define IF_FEATURE_INDIVIDUAL(...) __VA_ARGS__
51#endif
52
53#include "usage_compressed.h"
54
55#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
56static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
57#else
58# define usage_messages 0
59#endif
60
61#if ENABLE_FEATURE_COMPRESS_USAGE
62
63static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
64# include "bb_archive.h"
65static const char *unpack_usage_messages(void)
66{
67 char *outbuf = NULL;
68 bunzip_data *bd;
69 int i;
70
71 i = start_bunzip(&bd,
72 /* src_fd: */ -1,
73 /* inbuf: */ packed_usage,
74 /* len: */ sizeof(packed_usage));
75 /* read_bunzip can longjmp to start_bunzip, and ultimately
76 * end up here with i != 0 on read data errors! Not trivial */
77 if (!i) {
78 /* Cannot use xmalloc: will leak bd in NOFORK case! */
79 outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
80 if (outbuf)
81 read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
82 }
83 dealloc_bunzip(bd);
84 return outbuf;
85}
86# define dealloc_usage_messages(s) free(s)
87
88#else
89
90# define unpack_usage_messages() usage_messages
91# define dealloc_usage_messages(s) ((void)(s))
92
93#endif /* FEATURE_COMPRESS_USAGE */
94
95
96void FAST_FUNC bb_show_usage(void)
97{
98 if (ENABLE_SHOW_USAGE) {
99#ifdef SINGLE_APPLET_STR
100 /* Imagine that this applet is "true". Dont suck in printf! */
101 const char *usage_string = unpack_usage_messages();
102
103 if (*usage_string == '\b') {
104 full_write2_str("No help available.\n\n");
105 } else {
106 full_write2_str("Usage: "SINGLE_APPLET_STR" ");
107 full_write2_str(usage_string);
108 full_write2_str("\n\n");
109 }
110 if (ENABLE_FEATURE_CLEAN_UP)
111 dealloc_usage_messages((char*)usage_string);
112#else
113 const char *p;
114 const char *usage_string = p = unpack_usage_messages();
115 int ap = find_applet_by_name(applet_name);
116
117 if (ap < 0) /* never happens, paranoia */
118 xfunc_die();
119 while (ap) {
120 while (*p++) continue;
121 ap--;
122 }
123 full_write2_str(bb_banner);
124 full_write2_str(" multi-call binary.\n");
125 if (*p == '\b')
126 full_write2_str("\nNo help available.\n\n");
127 else {
128 full_write2_str("\nUsage: ");
129 full_write2_str(applet_name);
130 full_write2_str(" ");
131 full_write2_str(p);
132 full_write2_str("\n");
133 }
134 if (ENABLE_FEATURE_CLEAN_UP)
135 dealloc_usage_messages((char*)usage_string);
136#endif
137 }
138 xfunc_die();
139}
140
141int FAST_FUNC find_applet_by_name(const char *name)
142{
143 unsigned i, max;
144 int j;
145 const char *p;
146
147/* The commented-out word-at-a-time code is ~40% faster, but +160 bytes.
148 * "Faster" here saves ~0.5 microsecond of real time - not worth it.
149 */
150#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
151 uint32_t n32;
152
153 /* Handle all names < 2 chars long early */
154 if (name[0] == '\0')
155 return -1; /* "" is not a valid applet name */
156 if (name[1] == '\0') {
157 if (!ENABLE_TEST)
158 return -1; /* 1-char name is not valid */
159 if (name[0] != ']')
160 return -1; /* 1-char name which isn't "[" is not valid */
161 /* applet "[" is always applet #0: */
162 return 0;
163 }
164#endif
165
166 p = applet_names;
167 i = 0;
168#if KNOWN_APPNAME_OFFSETS <= 0
169 max = NUM_APPLETS;
170#else
171 max = NUM_APPLETS * KNOWN_APPNAME_OFFSETS;
172 for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
173 const char *pp = applet_names + applet_nameofs[j];
174 if (strcmp(name, pp) >= 0) {
175 //bb_error_msg("name:'%s' >= pp:'%s'", name, pp);
176 p = pp;
177 i = max - NUM_APPLETS;
178 break;
179 }
180 max -= NUM_APPLETS;
181 }
182 max /= (unsigned)KNOWN_APPNAME_OFFSETS;
183 i /= (unsigned)KNOWN_APPNAME_OFFSETS;
184 //bb_error_msg("name:'%s' starting from:'%s' i:%u max:%u", name, p, i, max);
185#endif
186
187 /* Open-coded linear search without strcmp/strlen calls for speed */
188
189#if 0 /*BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN*/
190 /* skip "[\0" name, it's surely not it */
191 if (ENABLE_TEST && LONE_CHAR(p, '['))
192 i++, p += 2;
193 /* All remaining applet names in p[] are at least 2 chars long */
194 /* name[] is also at least 2 chars long */
195
196 n32 = (name[0] << 0) | (name[1] << 8) | (name[2] << 16);
197 while (i < max) {
198 uint32_t p32;
199 char ch;
200
201 /* Quickly check match of the first 3 bytes */
202 move_from_unaligned32(p32, p);
203 p += 3;
204 if ((p32 & 0x00ffffff) != n32) {
205 /* Most likely case: 3 first bytes do not match */
206 i++;
207 if ((p32 & 0x00ff0000) == '\0')
208 continue; // p[2] was NUL
209 p++;
210 if ((p32 & 0xff000000) == '\0')
211 continue; // p[3] was NUL
212 /* p[0..3] aren't matching and none is NUL, check the rest */
213 while (*p++ != '\0')
214 continue;
215 continue;
216 }
217
218 /* Unlikely branch: first 3 bytes ([0..2]) match */
219 if ((p32 & 0x00ff0000) == '\0') {
220 /* name is 2-byte long, it is full match */
221 //bb_error_msg("found:'%s' i:%u", name, i);
222 return i;
223 }
224 /* Check remaining bytes [3..NUL] */
225 ch = (p32 >> 24);
226 j = 3;
227 while (ch == name[j]) {
228 if (ch == '\0') {
229 //bb_error_msg("found:'%s' i:%u", name, i);
230 return i;
231 }
232 ch = *++p;
233 j++;
234 }
235 /* Not a match. Skip it, including NUL */
236 while (ch != '\0')
237 ch = *++p;
238 p++;
239 i++;
240 }
241 return -1;
242#else
243 while (i < max) {
244 char ch;
245 j = 0;
246 /* Do we see "name\0" in applet_names[p] position? */
247 while ((ch = *p) == name[j]) {
248 if (ch == '\0') {
249 //bb_error_msg("found:'%s' i:%u", name, i);
250 return i; /* yes */
251 }
252 p++;
253 j++;
254 }
255 /* No.
256 * p => 1st non-matching char in applet_names[],
257 * skip to and including NUL.
258 */
259 while (ch != '\0')
260 ch = *++p;
261 p++;
262 i++;
263 }
264 return -1;
265#endif
266}
267
268
269void lbb_prepare(const char *applet
270 IF_FEATURE_INDIVIDUAL(, char **argv))
271 MAIN_EXTERNALLY_VISIBLE;
272void lbb_prepare(const char *applet
273 IF_FEATURE_INDIVIDUAL(, char **argv))
274{
275#ifdef __GLIBC__
276 (*(int **)&bb_errno) = __errno_location();
277 barrier();
278#endif
279 applet_name = applet;
280
281 if (ENABLE_LOCALE_SUPPORT)
282 setlocale(LC_ALL, "");
283
284#if ENABLE_FEATURE_INDIVIDUAL
285 /* Redundant for busybox (run_applet_and_exit covers that case)
286 * but needed for "individual applet" mode */
287 if (argv[1]
288 && !argv[2]
289 && strcmp(argv[1], "--help") == 0
290 && !is_prefixed_with(applet, "busybox")
291 ) {
292 /* Special case. POSIX says "test --help"
293 * should be no different from e.g. "test --foo". */
294 if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
295 bb_show_usage();
296 }
297#endif
298}
299
300/* The code below can well be in applets/applets.c, as it is used only
301 * for busybox binary, not "individual" binaries.
302 * However, keeping it here and linking it into libbusybox.so
303 * (together with remaining tiny applets/applets.o)
304 * makes it possible to avoid --whole-archive at link time.
305 * This makes (shared busybox) + libbusybox smaller.
306 * (--gc-sections would be even better....)
307 */
308
309const char *applet_name;
310#if !BB_MMU
311bool re_execed;
312#endif
313
314
315/* If not built as a single-applet executable... */
316#if !defined(SINGLE_APPLET_MAIN)
317
318IF_FEATURE_SUID(static uid_t ruid;) /* real uid */
319
320# if ENABLE_FEATURE_SUID_CONFIG
321
322static struct suid_config_t {
323 /* next ptr must be first: this struct needs to be llist-compatible */
324 struct suid_config_t *m_next;
325 struct bb_uidgid_t m_ugid;
326 int m_applet;
327 mode_t m_mode;
328} *suid_config;
329
330static bool suid_cfg_readable;
331
332/* check if u is member of group g */
333static int ingroup(uid_t u, gid_t g)
334{
335 struct group *grp = getgrgid(g);
336 if (grp) {
337 char **mem;
338 for (mem = grp->gr_mem; *mem; mem++) {
339 struct passwd *pwd = getpwnam(*mem);
340 if (pwd && (pwd->pw_uid == u))
341 return 1;
342 }
343 }
344 return 0;
345}
346
347/* libbb candidate */
348static char *get_trimmed_slice(char *s, char *e)
349{
350 /* First, consider the value at e to be nul and back up until we
351 * reach a non-space char. Set the char after that (possibly at
352 * the original e) to nul. */
353 while (e-- > s) {
354 if (!isspace(*e)) {
355 break;
356 }
357 }
358 e[1] = '\0';
359
360 /* Next, advance past all leading space and return a ptr to the
361 * first non-space char; possibly the terminating nul. */
362 return skip_whitespace(s);
363}
364
365static void parse_config_file(void)
366{
367 /* Don't depend on the tools to combine strings. */
368 static const char config_file[] ALIGN1 = "/etc/busybox.conf";
369
370 struct suid_config_t *sct_head;
371 int applet_no;
372 FILE *f;
373 const char *errmsg;
374 unsigned lc;
375 smallint section;
376 struct stat st;
377
378 ruid = getuid();
379 if (ruid == 0) /* run by root - don't need to even read config file */
380 return;
381
382 if ((stat(config_file, &st) != 0) /* No config file? */
383 || !S_ISREG(st.st_mode) /* Not a regular file? */
384 || (st.st_uid != 0) /* Not owned by root? */
385 || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
386 || !(f = fopen_for_read(config_file)) /* Cannot open? */
387 ) {
388 return;
389 }
390
391 suid_cfg_readable = 1;
392 sct_head = NULL;
393 section = lc = 0;
394
395 while (1) {
396 char buffer[256];
397 char *s;
398
399 if (!fgets(buffer, sizeof(buffer), f)) { /* Are we done? */
400 // Looks like bloat
401 //if (ferror(f)) { /* Make sure it wasn't a read error. */
402 // errmsg = "reading";
403 // goto pe_label;
404 //}
405 fclose(f);
406 suid_config = sct_head; /* Success, so set the pointer. */
407 return;
408 }
409
410 s = buffer;
411 lc++; /* Got a (partial) line. */
412
413 /* If a line is too long for our buffer, we consider it an error.
414 * The following test does mistreat one corner case though.
415 * If the final line of the file does not end with a newline and
416 * yet exactly fills the buffer, it will be treated as too long
417 * even though there isn't really a problem. But it isn't really
418 * worth adding code to deal with such an unlikely situation, and
419 * we do err on the side of caution. Besides, the line would be
420 * too long if it did end with a newline. */
421 if (!strchr(s, '\n') && !feof(f)) {
422 errmsg = "line too long";
423 goto pe_label;
424 }
425
426 /* Trim leading and trailing whitespace, ignoring comments, and
427 * check if the resulting string is empty. */
428 s = get_trimmed_slice(s, strchrnul(s, '#'));
429 if (!*s) {
430 continue;
431 }
432
433 /* Check for a section header. */
434
435 if (*s == '[') {
436 /* Unlike the old code, we ignore leading and trailing
437 * whitespace for the section name. We also require that
438 * there are no stray characters after the closing bracket. */
439 char *e = strchr(s, ']');
440 if (!e /* Missing right bracket? */
441 || e[1] /* Trailing characters? */
442 || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
443 ) {
444 errmsg = "section header";
445 goto pe_label;
446 }
447 /* Right now we only have one section so just check it.
448 * If more sections are added in the future, please don't
449 * resort to cascading ifs with multiple strcasecmp calls.
450 * That kind of bloated code is all too common. A loop
451 * and a string table would be a better choice unless the
452 * number of sections is very small. */
453 if (strcasecmp(s, "SUID") == 0) {
454 section = 1;
455 continue;
456 }
457 section = -1; /* Unknown section so set to skip. */
458 continue;
459 }
460
461 /* Process sections. */
462
463 if (section == 1) { /* SUID */
464 /* Since we trimmed leading and trailing space above, we're
465 * now looking for strings of the form
466 * <key>[::space::]*=[::space::]*<value>
467 * where both key and value could contain inner whitespace. */
468
469 /* First get the key (an applet name in our case). */
470 char *e = strchr(s, '=');
471 if (e) {
472 s = get_trimmed_slice(s, e);
473 }
474 if (!e || !*s) { /* Missing '=' or empty key. */
475 errmsg = "keyword";
476 goto pe_label;
477 }
478
479 /* Ok, we have an applet name. Process the rhs if this
480 * applet is currently built in and ignore it otherwise.
481 * Note: this can hide config file bugs which only pop
482 * up when the busybox configuration is changed. */
483 applet_no = find_applet_by_name(s);
484 if (applet_no >= 0) {
485 unsigned i;
486 struct suid_config_t *sct;
487
488 /* Note: We currently don't check for duplicates!
489 * The last config line for each applet will be the
490 * one used since we insert at the head of the list.
491 * I suppose this could be considered a feature. */
492 sct = xzalloc(sizeof(*sct));
493 sct->m_applet = applet_no;
494 /*sct->m_mode = 0;*/
495 sct->m_next = sct_head;
496 sct_head = sct;
497
498 /* Get the specified mode. */
499
500 e = skip_whitespace(e+1);
501
502 for (i = 0; i < 3; i++) {
503 /* There are 4 chars for each of user/group/other.
504 * "x-xx" instead of "x-" are to make
505 * "idx > 3" check catch invalid chars.
506 */
507 static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx";
508 static const unsigned short mode_mask[] ALIGN2 = {
509 S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */
510 S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */
511 S_IXOTH, 0 /* x- */
512 };
513 const char *q = strchrnul(mode_chars + 4*i, *e);
514 unsigned idx = q - (mode_chars + 4*i);
515 if (idx > 3) {
516 errmsg = "mode";
517 goto pe_label;
518 }
519 sct->m_mode |= mode_mask[q - mode_chars];
520 e++;
521 }
522
523 /* Now get the user/group info. */
524
525 s = skip_whitespace(e);
526 /* Default is 0.0, else parse USER.GROUP: */
527 if (*s) {
528 /* We require whitespace between mode and USER.GROUP */
529 if ((s == e) || !(e = strchr(s, '.'))) {
530 errmsg = "uid.gid";
531 goto pe_label;
532 }
533 *e = ':'; /* get_uidgid needs USER:GROUP syntax */
534 if (get_uidgid(&sct->m_ugid, s) == 0) {
535 errmsg = "unknown user/group";
536 goto pe_label;
537 }
538 }
539 }
540 continue;
541 }
542
543 /* Unknown sections are ignored. */
544
545 /* Encountering configuration lines prior to seeing a
546 * section header is treated as an error. This is how
547 * the old code worked, but it may not be desirable.
548 * We may want to simply ignore such lines in case they
549 * are used in some future version of busybox. */
550 if (!section) {
551 errmsg = "keyword outside section";
552 goto pe_label;
553 }
554 } /* while (1) */
555
556 pe_label:
557 fclose(f);
558 bb_error_msg("parse error in %s, line %u: %s", config_file, lc, errmsg);
559
560 /* Release any allocated memory before returning. */
561 llist_free((llist_t*)sct_head, NULL);
562}
563# else
564static inline void parse_config_file(void)
565{
566 IF_FEATURE_SUID(ruid = getuid();)
567}
568# endif /* FEATURE_SUID_CONFIG */
569
570
571# if ENABLE_FEATURE_SUID
572static void check_suid(int applet_no)
573{
574 gid_t rgid; /* real gid */
575
576 if (ruid == 0) /* set by parse_config_file() */
577 return; /* run by root - no need to check more */
578 rgid = getgid();
579
580# if ENABLE_FEATURE_SUID_CONFIG
581 if (suid_cfg_readable) {
582 uid_t uid;
583 struct suid_config_t *sct;
584 mode_t m;
585
586 for (sct = suid_config; sct; sct = sct->m_next) {
587 if (sct->m_applet == applet_no)
588 goto found;
589 }
590 goto check_need_suid;
591 found:
592 /* Is this user allowed to run this applet? */
593 m = sct->m_mode;
594 if (sct->m_ugid.uid == ruid)
595 /* same uid */
596 m >>= 6;
597 else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid))
598 /* same group / in group */
599 m >>= 3;
600 if (!(m & S_IXOTH)) /* is x bit not set? */
601 bb_error_msg_and_die("you have no permission to run this applet");
602
603 /* We set effective AND saved ids. If saved-id is not set
604 * like we do below, seteuid(0) can still later succeed! */
605
606 /* Are we directed to change gid
607 * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)?
608 */
609 if (sct->m_mode & S_ISGID)
610 rgid = sct->m_ugid.gid;
611 /* else: we will set egid = rgid, thus dropping sgid effect */
612 if (setresgid(-1, rgid, rgid))
613 bb_perror_msg_and_die("setresgid");
614
615 /* Are we directed to change uid
616 * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)?
617 */
618 uid = ruid;
619 if (sct->m_mode & S_ISUID)
620 uid = sct->m_ugid.uid;
621 /* else: we will set euid = ruid, thus dropping suid effect */
622 if (setresuid(-1, uid, uid))
623 bb_perror_msg_and_die("setresuid");
624
625 goto ret;
626 }
627# if !ENABLE_FEATURE_SUID_CONFIG_QUIET
628 {
629 static bool onetime = 0;
630
631 if (!onetime) {
632 onetime = 1;
633 bb_error_msg("using fallback suid method");
634 }
635 }
636# endif
637 check_need_suid:
638# endif
639 if (APPLET_SUID(applet_no) == BB_SUID_REQUIRE) {
640 /* Real uid is not 0. If euid isn't 0 too, suid bit
641 * is most probably not set on our executable */
642 if (geteuid())
643 bb_error_msg_and_die("must be suid to work properly");
644 } else if (APPLET_SUID(applet_no) == BB_SUID_DROP) {
645 xsetgid(rgid); /* drop all privileges */
646 xsetuid(ruid);
647 }
648# if ENABLE_FEATURE_SUID_CONFIG
649 ret: ;
650 llist_free((llist_t*)suid_config, NULL);
651# endif
652}
653# else
654# define check_suid(x) ((void)0)
655# endif /* FEATURE_SUID */
656
657
658# if ENABLE_FEATURE_INSTALLER
659static const char usr_bin [] ALIGN1 = "/usr/bin/";
660static const char usr_sbin[] ALIGN1 = "/usr/sbin/";
661static const char *const install_dir[] = {
662 &usr_bin [8], /* "/" */
663 &usr_bin [4], /* "/bin/" */
664 &usr_sbin[4] /* "/sbin/" */
665# if !ENABLE_INSTALL_NO_USR
666 ,usr_bin
667 ,usr_sbin
668# endif
669};
670
671/* create (sym)links for each applet */
672static void install_links(const char *busybox, int use_symbolic_links,
673 char *custom_install_dir)
674{
675 /* directory table
676 * this should be consistent w/ the enum,
677 * busybox.h::bb_install_loc_t, or else... */
678 int (*lf)(const char *, const char *);
679 char *fpc;
680 const char *appname = applet_names;
681 unsigned i;
682 int rc;
683
684 lf = link;
685 if (use_symbolic_links)
686 lf = symlink;
687
688 for (i = 0; i < ARRAY_SIZE(applet_main); i++) {
689 fpc = concat_path_file(
690 custom_install_dir ? custom_install_dir : install_dir[APPLET_INSTALL_LOC(i)],
691 appname);
692 // debug: bb_error_msg("%slinking %s to busybox",
693 // use_symbolic_links ? "sym" : "", fpc);
694 rc = lf(busybox, fpc);
695 if (rc != 0 && errno != EEXIST) {
696 bb_simple_perror_msg(fpc);
697 }
698 free(fpc);
699 while (*appname++ != '\0')
700 continue;
701 }
702}
703# elif ENABLE_BUSYBOX
704static void install_links(const char *busybox UNUSED_PARAM,
705 int use_symbolic_links UNUSED_PARAM,
706 char *custom_install_dir UNUSED_PARAM)
707{
708}
709# endif
710
711# if ENABLE_BUSYBOX
712static void run_applet_and_exit(const char *name, char **argv) NORETURN;
713
714/* If we were called as "busybox..." */
715static int busybox_main(char **argv)
716{
717 if (!argv[1]) {
718 /* Called without arguments */
719 const char *a;
720 int col;
721 unsigned output_width;
722 help:
723 output_width = 80;
724 if (ENABLE_FEATURE_AUTOWIDTH) {
725 /* Obtain the terminal width */
726 output_width = get_terminal_width(2);
727 }
728
729 dup2(1, 2);
730 full_write2_str(bb_banner); /* reuse const string */
731 full_write2_str(" multi-call binary.\n"); /* reuse */
732 full_write2_str(
733 "BusyBox is copyrighted by many authors between 1998-2015.\n"
734 "Licensed under GPLv2. See source distribution for detailed\n"
735 "copyright notices.\n"
736 "\n"
737 "Usage: busybox [function [arguments]...]\n"
738 " or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
739 IF_FEATURE_INSTALLER(
740 " or: busybox --install [-s] [DIR]\n"
741 )
742 " or: function [arguments]...\n"
743 "\n"
744 IF_NOT_FEATURE_SH_STANDALONE(
745 "\tBusyBox is a multi-call binary that combines many common Unix\n"
746 "\tutilities into a single executable. Most people will create a\n"
747 "\tlink to busybox for each function they wish to use and BusyBox\n"
748 "\twill act like whatever it was invoked as.\n"
749 )
750 IF_FEATURE_SH_STANDALONE(
751 "\tBusyBox is a multi-call binary that combines many common Unix\n"
752 "\tutilities into a single executable. The shell in this build\n"
753 "\tis configured to run built-in utilities without $PATH search.\n"
754 "\tYou don't need to install a link to busybox for each utility.\n"
755 "\tTo run external program, use full path (/sbin/ip instead of ip).\n"
756 )
757 "\n"
758 "Currently defined functions:\n"
759 );
760 col = 0;
761 a = applet_names;
762 /* prevent last comma to be in the very last pos */
763 output_width--;
764 while (*a) {
765 int len2 = strlen(a) + 2;
766 if (col >= (int)output_width - len2) {
767 full_write2_str(",\n");
768 col = 0;
769 }
770 if (col == 0) {
771 col = 6;
772 full_write2_str("\t");
773 } else {
774 full_write2_str(", ");
775 }
776 full_write2_str(a);
777 col += len2;
778 a += len2 - 1;
779 }
780 full_write2_str("\n");
781 return 0;
782 }
783
784 if (is_prefixed_with(argv[1], "--list")) {
785 unsigned i = 0;
786 const char *a = applet_names;
787 dup2(1, 2);
788 while (*a) {
789# if ENABLE_FEATURE_INSTALLER
790 if (argv[1][6]) /* --list-full? */
791 full_write2_str(install_dir[APPLET_INSTALL_LOC(i)] + 1);
792# endif
793 full_write2_str(a);
794 full_write2_str("\n");
795 i++;
796 while (*a++ != '\0')
797 continue;
798 }
799 return 0;
800 }
801
802 if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
803 int use_symbolic_links;
804 const char *busybox;
805
806 busybox = xmalloc_readlink(bb_busybox_exec_path);
807 if (!busybox) {
808 /* bb_busybox_exec_path is usually "/proc/self/exe".
809 * In chroot, readlink("/proc/self/exe") usually fails.
810 * In such case, better use argv[0] as symlink target
811 * if it is a full path name.
812 */
813 if (argv[0][0] != '/')
814 bb_error_msg_and_die("'%s' is not an absolute path", argv[0]);
815 busybox = argv[0];
816 }
817 /* busybox --install [-s] [DIR]:
818 * -s: make symlinks
819 * DIR: directory to install links to
820 */
821 use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && ++argv);
822 install_links(busybox, use_symbolic_links, argv[2]);
823 return 0;
824 }
825
826 if (strcmp(argv[1], "--help") == 0) {
827 /* "busybox --help [<applet>]" */
828 if (!argv[2])
829 goto help;
830 /* convert to "<applet> --help" */
831 argv[0] = argv[2];
832 argv[2] = NULL;
833 } else {
834 /* "busybox <applet> arg1 arg2 ..." */
835 argv++;
836 }
837 /* We support "busybox /a/path/to/applet args..." too. Allows for
838 * "#!/bin/busybox"-style wrappers */
839 applet_name = bb_get_last_path_component_nostrip(argv[0]);
840 run_applet_and_exit(applet_name, argv);
841}
842# endif
843
844# if NUM_APPLETS > 0
845void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
846{
847 int argc = 1;
848
849 while (argv[argc])
850 argc++;
851
852 /* Reinit some shared global data */
853 xfunc_error_retval = EXIT_FAILURE;
854 applet_name = bb_get_last_path_component_nostrip(argv[0]);
855
856 /* Special case. POSIX says "test --help"
857 * should be no different from e.g. "test --foo".
858 * Thus for "test", we skip --help check.
859 * "true" and "false" are also special.
860 */
861 if (1
862# if defined APPLET_NO_test
863 && applet_no != APPLET_NO_test
864# endif
865# if defined APPLET_NO_true
866 && applet_no != APPLET_NO_true
867# endif
868# if defined APPLET_NO_false
869 && applet_no != APPLET_NO_false
870# endif
871 ) {
872 if (argc == 2 && strcmp(argv[1], "--help") == 0) {
873 /* Make "foo --help" exit with 0: */
874 xfunc_error_retval = 0;
875 bb_show_usage();
876 }
877 }
878 if (ENABLE_FEATURE_SUID)
879 check_suid(applet_no);
880 xfunc_error_retval = applet_main[applet_no](argc, argv);
881 /* Note: applet_main() may also not return (die on a xfunc or such) */
882 xfunc_die();
883}
884# endif /* NUM_APPLETS > 0 */
885
886# if ENABLE_BUSYBOX || NUM_APPLETS > 0
887static NORETURN void run_applet_and_exit(const char *name, char **argv)
888{
889# if ENABLE_BUSYBOX
890 if (is_prefixed_with(name, "busybox"))
891 exit(busybox_main(argv));
892# endif
893# if NUM_APPLETS > 0
894 /* find_applet_by_name() search is more expensive, so goes second */
895 {
896 int applet = find_applet_by_name(name);
897 if (applet >= 0)
898 run_applet_no_and_exit(applet, argv);
899 }
900# endif
901
902 /*bb_error_msg_and_die("applet not found"); - links in printf */
903 full_write2_str(applet_name);
904 full_write2_str(": applet not found\n");
905 /* POSIX: "If a command is not found, the exit status shall be 127" */
906 exit(127);
907}
908# endif
909
910#endif /* !defined(SINGLE_APPLET_MAIN) */
911
912
913#if ENABLE_BUILD_LIBBUSYBOX
914int lbb_main(char **argv)
915#else
916int main(int argc UNUSED_PARAM, char **argv)
917#endif
918{
919#if 0
920 /* TODO: find a use for a block of memory between end of .bss
921 * and end of page. For example, I'm getting "_end:0x812e698 2408 bytes"
922 * - more than 2k of wasted memory (in this particular build)
923 * *per each running process*!
924 * (If your linker does not generate "_end" name, weak attribute
925 * makes &_end == NULL, end_len == 0 here.)
926 */
927 extern char _end[] __attribute__((weak));
928 unsigned end_len = (-(int)_end) & 0xfff;
929 printf("_end:%p %u bytes\n", &_end, end_len);
930#endif
931
932 /* Tweak malloc for reduced memory consumption */
933#ifdef M_TRIM_THRESHOLD
934 /* M_TRIM_THRESHOLD is the maximum amount of freed top-most memory
935 * to keep before releasing to the OS
936 * Default is way too big: 256k
937 */
938 mallopt(M_TRIM_THRESHOLD, 8 * 1024);
939#endif
940#ifdef M_MMAP_THRESHOLD
941 /* M_MMAP_THRESHOLD is the request size threshold for using mmap()
942 * Default is too big: 256k
943 */
944 mallopt(M_MMAP_THRESHOLD, 32 * 1024 - 256);
945#endif
946#if 0 /*def M_TOP_PAD*/
947 /* When the program break is increased, then M_TOP_PAD bytes are added
948 * to the sbrk(2) request. When the heap is trimmed because of free(3),
949 * this much free space is preserved at the top of the heap.
950 * glibc default seems to be way too big: 128k, but need to verify.
951 */
952 mallopt(M_TOP_PAD, 8 * 1024);
953#endif
954
955#if !BB_MMU
956 /* NOMMU re-exec trick sets high-order bit in first byte of name */
957 if (argv[0][0] & 0x80) {
958 re_execed = 1;
959 argv[0][0] &= 0x7f;
960 }
961#endif
962
963#if defined(SINGLE_APPLET_MAIN)
964
965 /* Only one applet is selected in .config */
966 if (argv[1] && is_prefixed_with(argv[0], "busybox")) {
967 /* "busybox <applet> <params>" should still work as expected */
968 argv++;
969 }
970 /* applet_names in this case is just "applet\0\0" */
971 lbb_prepare(applet_names IF_FEATURE_INDIVIDUAL(, argv));
972 return SINGLE_APPLET_MAIN(argc, argv);
973
974#elif !ENABLE_BUSYBOX && NUM_APPLETS == 0
975
976 full_write2_str(bb_basename(argv[0]));
977 full_write2_str(": no applets enabled\n");
978 exit(127);
979
980#else
981
982 lbb_prepare("busybox" IF_FEATURE_INDIVIDUAL(, argv));
983# if !ENABLE_BUSYBOX
984 if (argv[1] && is_prefixed_with(bb_basename(argv[0]), "busybox"))
985 argv++;
986# endif
987 applet_name = argv[0];
988 if (applet_name[0] == '-')
989 applet_name++;
990 applet_name = bb_basename(applet_name);
991 parse_config_file(); /* ...maybe, if FEATURE_SUID_CONFIG */
992 run_applet_and_exit(applet_name, argv);
993
994#endif
995}
996
generated by cgit at 2024-05-14 16:38:20 (GMT)