libbb/appletlib.c

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