lib/util/util.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2001-2002
   6    Copyright (C) Simo Sorce 2001-2011
   7    Copyright (C) Jim McDonough (jmcd@us.ibm.com)  2003.
   8    Copyright (C) James J Myers 2003
   9    Copyright (C) Volker Lendecke 2010
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "replace.h"
  26 #include <talloc.h>
  27 #include "system/network.h"
  28 #include "system/filesys.h"
  29 #include "system/locale.h"
  30 #include "system/shmem.h"
  31 #include "system/passwd.h"
  32 #include "system/time.h"
  33 #include "system/wait.h"
  34 #include "debug.h"
  35 #include "samba_util.h"
  36
  37 #undef malloc
  38 #undef strcasecmp
  39 #undef strncasecmp
  40 #undef strdup
  41 #undef realloc
  42 #undef calloc
  43
  44 /**
  45  * @file
  46  * @brief Misc utility functions
  47  */
  48
  49 /**
  50  Find a suitable temporary directory. The result should be copied immediately
  51  as it may be overwritten by a subsequent call.
  52 **/
  53 _PUBLIC_ const char *tmpdir(void)
  54 {
  55         char *p;
  56         if ((p = getenv("TMPDIR")))
  57                 return p;
  58         return "/tmp";
  59 }
  60
  61
  62 /**
  63  Create a tmp file, open it and immediately unlink it.
  64  If dir is NULL uses tmpdir()
  65  Returns the file descriptor or -1 on error.
  66 **/
  67 int create_unlink_tmp(const char *dir)
  68 {
  69         size_t len = strlen(dir ? dir : (dir = tmpdir()));
  70         char fname[len+25];
  71         int fd;
  72         mode_t mask;
  73
  74         len = snprintf(fname, sizeof(fname), "%s/listenerlock_XXXXXX", dir);
  75         if (len >= sizeof(fname)) {
  76                 errno = ENOMEM;
  77                 return -1;
  78         }
  79         mask = umask(S_IRWXO | S_IRWXG);
  80         fd = mkstemp(fname);
  81         umask(mask);
  82         if (fd == -1) {
  83                 return -1;
  84         }
  85         if (unlink(fname) == -1) {
  86                 int sys_errno = errno;
  87                 close(fd);
  88                 errno = sys_errno;
  89                 return -1;
  90         }
  91         return fd;
  92 }
  93
  94
  95 /**
  96  Check if a file exists - call vfs_file_exist for samba files.
  97 **/
  98 _PUBLIC_ bool file_exist(const char *fname)
  99 {
 100         struct stat st;
 101
 102         if (stat(fname, &st) != 0) {
 103                 return false;
 104         }
 105
 106         return ((S_ISREG(st.st_mode)) || (S_ISFIFO(st.st_mode)));
 107 }
 108
 109 /**
 110  Check a files mod time.
 111 **/
 112
 113 _PUBLIC_ time_t file_modtime(const char *fname)
 114 {
 115         struct stat st;
 116
 117         if (stat(fname,&st) != 0)
 118                 return(0);
 119
 120         return(st.st_mtime);
 121 }
 122
 123 /**
 124  Check file permissions.
 125 **/
 126
 127 _PUBLIC_ bool file_check_permissions(const char *fname,
 128                                      uid_t uid,
 129                                      mode_t file_perms,
 130                                      struct stat *pst)
 131 {
 132         int ret;
 133         struct stat st;
 134
 135         if (pst == NULL) {
 136                 pst = &st;
 137         }
 138
 139         ZERO_STRUCTP(pst);
 140
 141         ret = stat(fname, pst);
 142         if (ret != 0) {
 143                 DEBUG(0, ("stat failed on file '%s': %s\n",
 144                          fname, strerror(errno)));
 145                 return false;
 146         }
 147
 148         if (pst->st_uid != uid && !uid_wrapper_enabled()) {
 149                 DEBUG(0, ("invalid ownership of file '%s': "
 150                          "owned by uid %u, should be %u\n",
 151                          fname, (unsigned int)pst->st_uid,
 152                          (unsigned int)uid));
 153                 return false;
 154         }
 155
 156         if ((pst->st_mode & 0777) != file_perms) {
 157                 DEBUG(0, ("invalid permissions on file "
 158                          "'%s': has 0%o should be 0%o\n", fname,
 159                          (unsigned int)(pst->st_mode & 0777),
 160                          (unsigned int)file_perms));
 161                 return false;
 162         }
 163
 164         return true;
 165 }
 166
 167 /**
 168  Check if a directory exists.
 169 **/
 170
 171 _PUBLIC_ bool directory_exist(const char *dname)
 172 {
 173         struct stat st;
 174         bool ret;
 175
 176         if (stat(dname,&st) != 0) {
 177                 return false;
 178         }
 179
 180         ret = S_ISDIR(st.st_mode);
 181         if(!ret)
 182                 errno = ENOTDIR;
 183         return ret;
 184 }
 185
 186 /**
 187  * Try to create the specified directory if it didn't exist.
 188  *
 189  * @retval true if the directory already existed
 190  * or was successfully created.
 191  */
 192 _PUBLIC_ bool directory_create_or_exist(const char *dname,
 193                                         mode_t dir_perms)
 194 {
 195         int ret;
 196         struct stat st;
 197         mode_t old_umask;
 198
 199         ret = lstat(dname, &st);
 200         if (ret == 0) {
 201                 return true;
 202         }
 203
 204         if (errno != ENOENT) {
 205                 DBG_WARNING("lstat failed on directory %s: %s\n",
 206                             dname, strerror(errno));
 207                 return false;
 208         }
 209
 210         /* Create directory */
 211         old_umask = umask(0);
 212         ret = mkdir(dname, dir_perms);
 213         if (ret == -1 && errno != EEXIST) {
 214                 DEBUG(0, ("mkdir failed on directory "
 215                           "%s: %s\n", dname,
 216                           strerror(errno)));
 217                 umask(old_umask);
 218                 return false;
 219         }
 220         umask(old_umask);
 221
 222         ret = lstat(dname, &st);
 223         if (ret == -1) {
 224                 DEBUG(0, ("lstat failed on created directory %s: %s\n",
 225                           dname, strerror(errno)));
 226                 return false;
 227         }
 228
 229         return true;
 230 }
 231
 232 /**
 233  * @brief Try to create a specified directory if it doesn't exist.
 234  *
 235  * The function creates a directory with the given uid and permissions if it
 236  * doesn't exist. If it exists it makes sure the uid and permissions are
 237  * correct and it will fail if they are different.
 238  *
 239  * @param[in]  dname  The directory to create.
 240  *
 241  * @param[in]  uid    The uid the directory needs to belong too.
 242  *
 243  * @param[in]  dir_perms  The expected permissions of the directory.
 244  *
 245  * @return True on success, false on error.
 246  */
 247 _PUBLIC_ bool directory_create_or_exist_strict(const char *dname,
 248                                                uid_t uid,
 249                                                mode_t dir_perms)
 250 {
 251         struct stat st;
 252         bool ok;
 253         int rc;
 254
 255         ok = directory_create_or_exist(dname, dir_perms);
 256         if (!ok) {
 257                 return false;
 258         }
 259
 260         rc = lstat(dname, &st);
 261         if (rc == -1) {
 262                 DEBUG(0, ("lstat failed on created directory %s: %s\n",
 263                           dname, strerror(errno)));
 264                 return false;
 265         }
 266
 267         /* Check ownership and permission on existing directory */
 268         if (!S_ISDIR(st.st_mode)) {
 269                 DEBUG(0, ("directory %s isn't a directory\n",
 270                         dname));
 271                 return false;
 272         }
 273         if (st.st_uid != uid && !uid_wrapper_enabled()) {
 274                 DBG_NOTICE("invalid ownership on directory "
 275                           "%s\n", dname);
 276                 return false;
 277         }
 278         if ((st.st_mode & 0777) != dir_perms) {
 279                 DEBUG(0, ("invalid permissions on directory "
 280                           "'%s': has 0%o should be 0%o\n", dname,
 281                           (unsigned int)(st.st_mode & 0777), (unsigned int)dir_perms));
 282                 return false;
 283         }
 284
 285         return true;
 286 }
 287
 288
 289 /**
 290  Sleep for a specified number of milliseconds.
 291 **/
 292
 293 _PUBLIC_ void smb_msleep(unsigned int t)
 294 {
 295 #if defined(HAVE_NANOSLEEP)
 296         struct timespec ts;
 297         int ret;
 298
 299         ts.tv_sec = t/1000;
 300         ts.tv_nsec = 1000000*(t%1000);
 301
 302         do {
 303                 errno = 0;
 304                 ret = nanosleep(&ts, &ts);
 305         } while (ret < 0 && errno == EINTR && (ts.tv_sec > 0 || ts.tv_nsec > 0));
 306 #else
 307         unsigned int tdiff=0;
 308         struct timeval tval,t1,t2;
 309         fd_set fds;
 310
 311         GetTimeOfDay(&t1);
 312         t2 = t1;
 313
 314         while (tdiff < t) {
 315                 tval.tv_sec = (t-tdiff)/1000;
 316                 tval.tv_usec = 1000*((t-tdiff)%1000);
 317
 318                 /* Never wait for more than 1 sec. */
 319                 if (tval.tv_sec > 1) {
 320                         tval.tv_sec = 1;
 321                         tval.tv_usec = 0;
 322                 }
 323
 324                 FD_ZERO(&fds);
 325                 errno = 0;
 326                 select(0,&fds,NULL,NULL,&tval);
 327
 328                 GetTimeOfDay(&t2);
 329                 if (t2.tv_sec < t1.tv_sec) {
 330                         /* Someone adjusted time... */
 331                         t1 = t2;
 332                 }
 333
 334                 tdiff = usec_time_diff(&t2,&t1)/1000;
 335         }
 336 #endif
 337 }
 338
 339 /**
 340  Get my own name, return in talloc'ed storage.
 341 **/
 342
 343 _PUBLIC_ char *get_myname(TALLOC_CTX *ctx)
 344 {
 345         char *p;
 346         char hostname[HOST_NAME_MAX];
 347
 348         /* get my host name */
 349         if (gethostname(hostname, sizeof(hostname)) == -1) {
 350                 DEBUG(0,("gethostname failed\n"));
 351                 return NULL;
 352         }
 353
 354         /* Ensure null termination. */
 355         hostname[sizeof(hostname)-1] = '\0';
 356
 357         /* split off any parts after an initial . */
 358         p = strchr_m(hostname, '.');
 359         if (p) {
 360                 *p = 0;
 361         }
 362
 363         return talloc_strdup(ctx, hostname);
 364 }
 365
 366 /**
 367  Check if a process exists. Does this work on all unixes?
 368 **/
 369
 370 _PUBLIC_ bool process_exists_by_pid(pid_t pid)
 371 {
 372         /* Doing kill with a non-positive pid causes messages to be
 373          * sent to places we don't want. */
 374         if (pid <= 0) {
 375                 return false;
 376         }
 377         return(kill(pid,0) == 0 || errno != ESRCH);
 378 }
 379
 380 /**
 381  Simple routine to do POSIX file locking. Cruft in NFS and 64->32 bit mapping
 382  is dealt with in posix.c
 383 **/
 384
 385 _PUBLIC_ bool fcntl_lock(int fd, int op, off_t offset, off_t count, int type)
 386 {
 387         struct flock lock;
 388         int ret;
 389
 390         DEBUG(8,("fcntl_lock %d %d %.0f %.0f %d\n",fd,op,(double)offset,(double)count,type));
 391
 392         lock.l_type = type;
 393         lock.l_whence = SEEK_SET;
 394         lock.l_start = offset;
 395         lock.l_len = count;
 396         lock.l_pid = 0;
 397
 398         ret = fcntl(fd,op,&lock);
 399
 400         if (ret == -1 && errno != 0)
 401                 DEBUG(3,("fcntl_lock: fcntl lock gave errno %d (%s)\n",errno,strerror(errno)));
 402
 403         /* a lock query */
 404         if (op == F_GETLK) {
 405                 if ((ret != -1) &&
 406                                 (lock.l_type != F_UNLCK) &&
 407                                 (lock.l_pid != 0) &&
 408                                 (lock.l_pid != getpid())) {
 409                         DEBUG(3,("fcntl_lock: fd %d is locked by pid %d\n",fd,(int)lock.l_pid));
 410                         return true;
 411                 }
 412
 413                 /* it must be not locked or locked by me */
 414                 return false;
 415         }
 416
 417         /* a lock set or unset */
 418         if (ret == -1) {
 419                 DEBUG(3,("fcntl_lock: lock failed at offset %.0f count %.0f op %d type %d (%s)\n",
 420                         (double)offset,(double)count,op,type,strerror(errno)));
 421                 return false;
 422         }
 423
 424         /* everything went OK */
 425         DEBUG(8,("fcntl_lock: Lock call successful\n"));
 426
 427         return true;
 428 }
 429
 430 struct debug_channel_level {
 431         int channel;
 432         int level;
 433 };
 434
 435 static void debugadd_channel_cb(const char *buf, void *private_data)
 436 {
 437         struct debug_channel_level *dcl =
 438                 (struct debug_channel_level *)private_data;
 439
 440         DEBUGADDC(dcl->channel, dcl->level,("%s", buf));
 441 }
 442
 443 static void debugadd_cb(const char *buf, void *private_data)
 444 {
 445         int *plevel = (int *)private_data;
 446         DEBUGADD(*plevel, ("%s", buf));
 447 }
 448
 449 void print_asc_cb(const uint8_t *buf, int len,
 450                   void (*cb)(const char *buf, void *private_data),
 451                   void *private_data)
 452 {
 453         int i;
 454         char s[2];
 455         s[1] = 0;
 456
 457         for (i=0; i<len; i++) {
 458                 s[0] = isprint(buf[i]) ? buf[i] : '.';
 459                 cb(s, private_data);
 460         }
 461 }
 462
 463 void print_asc(int level, const uint8_t *buf,int len)
 464 {
 465         print_asc_cb(buf, len, debugadd_cb, &level);
 466 }
 467
 468 /**
 469  * Write dump of binary data to a callback
 470  */
 471 void dump_data_cb(const uint8_t *buf, int len,
 472                   bool omit_zero_bytes,
 473                   void (*cb)(const char *buf, void *private_data),
 474                   void *private_data)
 475 {
 476         int i=0;
 477         static const uint8_t empty[16] = { 0, };
 478         bool skipped = false;
 479         char tmp[16];
 480
 481         if (len<=0) return;
 482
 483         for (i=0;i<len;) {
 484
 485                 if (i%16 == 0) {
 486                         if ((omit_zero_bytes == true) &&
 487                             (i > 0) &&
 488                             (len > i+16) &&
 489                             (memcmp(&buf[i], &empty, 16) == 0))
 490                         {
 491                                 i +=16;
 492                                 continue;
 493                         }
 494
 495                         if (i<len)  {
 496                                 snprintf(tmp, sizeof(tmp), "[%04X] ", i);
 497                                 cb(tmp, private_data);
 498                         }
 499                 }
 500
 501                 snprintf(tmp, sizeof(tmp), "%02X ", (int)buf[i]);
 502                 cb(tmp, private_data);
 503                 i++;
 504                 if (i%8 == 0) {
 505                         cb("  ", private_data);
 506                 }
 507                 if (i%16 == 0) {
 508
 509                         print_asc_cb(&buf[i-16], 8, cb, private_data);
 510                         cb(" ", private_data);
 511                         print_asc_cb(&buf[i-8], 8, cb, private_data);
 512                         cb("\n", private_data);
 513
 514                         if ((omit_zero_bytes == true) &&
 515                             (len > i+16) &&
 516                             (memcmp(&buf[i], &empty, 16) == 0)) {
 517                                 if (!skipped) {
 518                                         cb("skipping zero buffer bytes\n",
 519                                            private_data);
 520                                         skipped = true;
 521                                 }
 522                         }
 523                 }
 524         }
 525
 526         if (i%16) {
 527                 int n;
 528                 n = 16 - (i%16);
 529                 cb("  ", private_data);
 530                 if (n>8) {
 531                         cb(" ", private_data);
 532                 }
 533                 while (n--) {
 534                         cb("   ", private_data);
 535                 }
 536                 n = MIN(8,i%16);
 537                 print_asc_cb(&buf[i-(i%16)], n, cb, private_data);
 538                 cb(" ", private_data);
 539                 n = (i%16) - n;
 540                 if (n>0) {
 541                         print_asc_cb(&buf[i-n], n, cb, private_data);
 542                 }
 543                 cb("\n", private_data);
 544         }
 545
 546 }
 547
 548 /**
 549  * Write dump of binary data to the log file.
 550  *
 551  * The data is only written if the log level is at least level.
 552  */
 553 _PUBLIC_ void dump_data(int level, const uint8_t *buf, int len)
 554 {
 555         if (!DEBUGLVL(level)) {
 556                 return;
 557         }
 558         dump_data_cb(buf, len, false, debugadd_cb, &level);
 559 }
 560
 561 /**
 562  * Write dump of binary data to the log file.
 563  *
 564  * The data is only written if the log level is at least level for
 565  * debug class dbgc_class.
 566  */
 567 _PUBLIC_ void dump_data_dbgc(int dbgc_class, int level, const uint8_t *buf, int len)
 568 {
 569         struct debug_channel_level dcl = { dbgc_class, level };
 570
 571         if (!DEBUGLVLC(dbgc_class, level)) {
 572                 return;
 573         }
 574         dump_data_cb(buf, len, false, debugadd_channel_cb, &dcl);
 575 }
 576
 577 /**
 578  * Write dump of binary data to the log file.
 579  *
 580  * The data is only written if the log level is at least level.
 581  * 16 zero bytes in a row are omitted
 582  */
 583 _PUBLIC_ void dump_data_skip_zeros(int level, const uint8_t *buf, int len)
 584 {
 585         if (!DEBUGLVL(level)) {
 586                 return;
 587         }
 588         dump_data_cb(buf, len, true, debugadd_cb, &level);
 589 }
 590
 591 static void fprintf_cb(const char *buf, void *private_data)
 592 {
 593         FILE *f = (FILE *)private_data;
 594         fprintf(f, "%s", buf);
 595 }
 596
 597 void dump_data_file(const uint8_t *buf, int len, bool omit_zero_bytes,
 598                     FILE *f)
 599 {
 600         dump_data_cb(buf, len, omit_zero_bytes, fprintf_cb, f);
 601 }
 602
 603 /**
 604  malloc that aborts with smb_panic on fail or zero size.
 605 **/
 606
 607 _PUBLIC_ void *smb_xmalloc(size_t size)
 608 {
 609         void *p;
 610         if (size == 0)
 611                 smb_panic("smb_xmalloc: called with zero size.\n");
 612         if ((p = malloc(size)) == NULL)
 613                 smb_panic("smb_xmalloc: malloc fail.\n");
 614         return p;
 615 }
 616
 617 /**
 618  Memdup with smb_panic on fail.
 619 **/
 620
 621 _PUBLIC_ void *smb_xmemdup(const void *p, size_t size)
 622 {
 623         void *p2;
 624         p2 = smb_xmalloc(size);
 625         memcpy(p2, p, size);
 626         return p2;
 627 }
 628
 629 /**
 630  strdup that aborts on malloc fail.
 631 **/
 632
 633 char *smb_xstrdup(const char *s)
 634 {
 635 #if defined(PARANOID_MALLOC_CHECKER)
 636 #ifdef strdup
 637 #undef strdup
 638 #endif
 639 #endif
 640
 641 #ifndef HAVE_STRDUP
 642 #define strdup rep_strdup
 643 #endif
 644
 645         char *s1 = strdup(s);
 646 #if defined(PARANOID_MALLOC_CHECKER)
 647 #ifdef strdup
 648 #undef strdup
 649 #endif
 650 #define strdup(s) __ERROR_DONT_USE_STRDUP_DIRECTLY
 651 #endif
 652         if (!s1) {
 653                 smb_panic("smb_xstrdup: malloc failed");
 654         }
 655         return s1;
 656
 657 }
 658
 659 /**
 660  strndup that aborts on malloc fail.
 661 **/
 662
 663 char *smb_xstrndup(const char *s, size_t n)
 664 {
 665 #if defined(PARANOID_MALLOC_CHECKER)
 666 #ifdef strndup
 667 #undef strndup
 668 #endif
 669 #endif
 670
 671 #if (defined(BROKEN_STRNDUP) || !defined(HAVE_STRNDUP))
 672 #undef HAVE_STRNDUP
 673 #define strndup rep_strndup
 674 #endif
 675
 676         char *s1 = strndup(s, n);
 677 #if defined(PARANOID_MALLOC_CHECKER)
 678 #ifdef strndup
 679 #undef strndup
 680 #endif
 681 #define strndup(s,n) __ERROR_DONT_USE_STRNDUP_DIRECTLY
 682 #endif
 683         if (!s1) {
 684                 smb_panic("smb_xstrndup: malloc failed");
 685         }
 686         return s1;
 687 }
 688
 689
 690
 691 /**
 692  Like strdup but for memory.
 693 **/
 694
 695 _PUBLIC_ void *smb_memdup(const void *p, size_t size)
 696 {
 697         void *p2;
 698         if (size == 0)
 699                 return NULL;
 700         p2 = malloc(size);
 701         if (!p2)
 702                 return NULL;
 703         memcpy(p2, p, size);
 704         return p2;
 705 }
 706
 707 /**
 708  * Write a password to the log file.
 709  *
 710  * @note Only actually does something if DEBUG_PASSWORD was defined during
 711  * compile-time.
 712  */
 713 _PUBLIC_ void dump_data_pw(const char *msg, const uint8_t * data, size_t len)
 714 {
 715 #ifdef DEBUG_PASSWORD
 716         DEBUG(11, ("%s", msg));
 717         if (data != NULL && len > 0)
 718         {
 719                 dump_data(11, data, len);
 720         }
 721 #endif
 722 }
 723
 724
 725 /**
 726  * see if a range of memory is all zero. A NULL pointer is considered
 727  * to be all zero
 728  */
 729 _PUBLIC_ bool all_zero(const uint8_t *ptr, size_t size)
 730 {
 731         size_t i;
 732         if (!ptr) return true;
 733         for (i=0;i<size;i++) {
 734                 if (ptr[i]) return false;
 735         }
 736         return true;
 737 }
 738
 739 /**
 740   realloc an array, checking for integer overflow in the array size
 741 */
 742 _PUBLIC_ void *realloc_array(void *ptr, size_t el_size, unsigned count, bool free_on_fail)
 743 {
 744 #define MAX_MALLOC_SIZE 0x7fffffff
 745         if (count == 0 ||
 746             count >= MAX_MALLOC_SIZE/el_size) {
 747                 if (free_on_fail)
 748                         SAFE_FREE(ptr);
 749                 return NULL;
 750         }
 751         if (!ptr) {
 752                 return malloc(el_size * count);
 753         }
 754         return realloc(ptr, el_size * count);
 755 }
 756
 757 /****************************************************************************
 758  Type-safe malloc.
 759 ****************************************************************************/
 760
 761 void *malloc_array(size_t el_size, unsigned int count)
 762 {
 763         return realloc_array(NULL, el_size, count, false);
 764 }
 765
 766 /****************************************************************************
 767  Type-safe memalign
 768 ****************************************************************************/
 769
 770 void *memalign_array(size_t el_size, size_t align, unsigned int count)
 771 {
 772         if (el_size == 0 || count >= MAX_MALLOC_SIZE/el_size) {
 773                 return NULL;
 774         }
 775
 776         return memalign(align, el_size*count);
 777 }
 778
 779 /****************************************************************************
 780  Type-safe calloc.
 781 ****************************************************************************/
 782
 783 void *calloc_array(size_t size, size_t nmemb)
 784 {
 785         if (nmemb >= MAX_MALLOC_SIZE/size) {
 786                 return NULL;
 787         }
 788         if (size == 0 || nmemb == 0) {
 789                 return NULL;
 790         }
 791         return calloc(nmemb, size);
 792 }
 793
 794 /**
 795  Trim the specified elements off the front and back of a string.
 796 **/
 797 _PUBLIC_ bool trim_string(char *s, const char *front, const char *back)
 798 {
 799         bool ret = false;
 800         size_t front_len;
 801         size_t back_len;
 802         size_t len;
 803
 804         /* Ignore null or empty strings. */
 805         if (!s || (s[0] == '\0')) {
 806                 return false;
 807         }
 808         len = strlen(s);
 809
 810         front_len       = front? strlen(front) : 0;
 811         back_len        = back? strlen(back) : 0;
 812
 813         if (front_len) {
 814                 size_t front_trim = 0;
 815
 816                 while (strncmp(s+front_trim, front, front_len)==0) {
 817                         front_trim += front_len;
 818                 }
 819                 if (front_trim > 0) {
 820                         /* Must use memmove here as src & dest can
 821                          * easily overlap. Found by valgrind. JRA. */
 822                         memmove(s, s+front_trim, (len-front_trim)+1);
 823                         len -= front_trim;
 824                         ret=true;
 825                 }
 826         }
 827
 828         if (back_len) {
 829                 while ((len >= back_len) && strncmp(s+len-back_len,back,back_len)==0) {
 830                         s[len-back_len]='\0';
 831                         len -= back_len;
 832                         ret=true;
 833                 }
 834         }
 835         return ret;
 836 }
 837
 838 /**
 839  Find the number of 'c' chars in a string
 840 **/
 841 _PUBLIC_ _PURE_ size_t count_chars(const char *s, char c)
 842 {
 843         size_t count = 0;
 844
 845         while (*s) {
 846                 if (*s == c) count++;
 847                 s ++;
 848         }
 849
 850         return count;
 851 }
 852
 853 /**
 854  * Routine to get hex characters and turn them into a byte array.
 855  * the array can be variable length.
 856  * -  "0xnn" or "0Xnn" is specially catered for.
 857  * - The first non-hex-digit character (apart from possibly leading "0x"
 858  *   finishes the conversion and skips the rest of the input.
 859  * - A single hex-digit character at the end of the string is skipped.
 860  *
 861  * valid examples: "0A5D15"; "0x123456"
 862  */
 863 _PUBLIC_ size_t strhex_to_str(char *p, size_t p_len, const char *strhex, size_t strhex_len)
 864 {
 865         size_t i = 0;
 866         size_t num_chars = 0;
 867         uint8_t   lonybble, hinybble;
 868         const char     *hexchars = "0123456789ABCDEF";
 869         char           *p1 = NULL, *p2 = NULL;
 870
 871         /* skip leading 0x prefix */
 872         if (strncasecmp(strhex, "0x", 2) == 0) {
 873                 i += 2; /* skip two chars */
 874         }
 875
 876         for (; i+1 < strhex_len && strhex[i] != 0 && strhex[i+1] != 0; i++) {
 877                 p1 = strchr(hexchars, toupper((unsigned char)strhex[i]));
 878                 if (p1 == NULL) {
 879                         break;
 880                 }
 881
 882                 i++; /* next hex digit */
 883
 884                 p2 = strchr(hexchars, toupper((unsigned char)strhex[i]));
 885                 if (p2 == NULL) {
 886                         break;
 887                 }
 888
 889                 /* get the two nybbles */
 890                 hinybble = PTR_DIFF(p1, hexchars);
 891                 lonybble = PTR_DIFF(p2, hexchars);
 892
 893                 if (num_chars >= p_len) {
 894                         break;
 895                 }
 896
 897                 p[num_chars] = (hinybble << 4) | lonybble;
 898                 num_chars++;
 899
 900                 p1 = NULL;
 901                 p2 = NULL;
 902         }
 903         return num_chars;
 904 }
 905
 906 /**
 907  * Parse a hex string and return a data blob.
 908  */
 909 _PUBLIC_ _PURE_ DATA_BLOB strhex_to_data_blob(TALLOC_CTX *mem_ctx, const char *strhex)
 910 {
 911         DATA_BLOB ret_blob = data_blob_talloc(mem_ctx, NULL, strlen(strhex)/2+1);
 912
 913         ret_blob.length = strhex_to_str((char *)ret_blob.data, ret_blob.length,
 914                                         strhex,
 915                                         strlen(strhex));
 916
 917         return ret_blob;
 918 }
 919
 920 /**
 921  * Print a buf in hex. Assumes dst is at least (srclen*2)+1 large.
 922  */
 923 _PUBLIC_ void hex_encode_buf(char *dst, const uint8_t *src, size_t srclen)
 924 {
 925         size_t i;
 926         for (i=0; i<srclen; i++) {
 927                 snprintf(dst + i*2, 3, "%02X", src[i]);
 928         }
 929         /*
 930          * Ensure 0-termination for 0-length buffers
 931          */
 932         dst[srclen*2] = '\0';
 933 }
 934
 935 /**
 936  * talloc version of hex_encode_buf()
 937  */
 938 _PUBLIC_ char *hex_encode_talloc(TALLOC_CTX *mem_ctx, const unsigned char *buff_in, size_t len)
 939 {
 940         char *hex_buffer;
 941
 942         hex_buffer = talloc_array(mem_ctx, char, (len*2)+1);
 943         if (!hex_buffer) {
 944                 return NULL;
 945         }
 946         hex_encode_buf(hex_buffer, buff_in, len);
 947         talloc_set_name_const(hex_buffer, hex_buffer);
 948         return hex_buffer;
 949 }
 950
 951 /**
 952   varient of strcmp() that handles NULL ptrs
 953 **/
 954 _PUBLIC_ int strcmp_safe(const char *s1, const char *s2)
 955 {
 956         if (s1 == s2) {
 957                 return 0;
 958         }
 959         if (s1 == NULL || s2 == NULL) {
 960                 return s1?-1:1;
 961         }
 962         return strcmp(s1, s2);
 963 }
 964
 965
 966 /**
 967 return the number of bytes occupied by a buffer in ASCII format
 968 the result includes the null termination
 969 limited by 'n' bytes
 970 **/
 971 _PUBLIC_ size_t ascii_len_n(const char *src, size_t n)
 972 {
 973         size_t len;
 974
 975         len = strnlen(src, n);
 976         if (len+1 <= n) {
 977                 len += 1;
 978         }
 979
 980         return len;
 981 }
 982
 983 struct anonymous_shared_header {
 984         union {
 985                 size_t length;
 986                 uint8_t pad[16];
 987         } u;
 988 };
 989
 990 /* Map a shared memory buffer of at least nelem counters. */
 991 void *anonymous_shared_allocate(size_t orig_bufsz)
 992 {
 993         void *ptr;
 994         void *buf;
 995         size_t pagesz = getpagesize();
 996         size_t pagecnt;
 997         size_t bufsz = orig_bufsz;
 998         struct anonymous_shared_header *hdr;
 999
1000         bufsz += sizeof(*hdr);
1001
1002         /* round up to full pages */
1003         pagecnt = bufsz / pagesz;
1004         if (bufsz % pagesz) {
1005                 pagecnt += 1;
1006         }
1007         bufsz = pagesz * pagecnt;
1008
1009         if (orig_bufsz >= bufsz) {
1010                 /* integer wrap */
1011                 errno = ENOMEM;
1012                 return NULL;
1013         }
1014
1015 #ifdef MAP_ANON
1016         /* BSD */
1017         buf = mmap(NULL, bufsz, PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED,
1018                         -1 /* fd */, 0 /* offset */);
1019 #else
1020 {
1021         int saved_errno;
1022         int fd;
1023
1024         fd = open("/dev/zero", O_RDWR);
1025         if (fd == -1) {
1026                 return NULL;
1027         }
1028
1029         buf = mmap(NULL, bufsz, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED,
1030                    fd, 0 /* offset */);
1031         saved_errno = errno;
1032         close(fd);
1033         errno = saved_errno;
1034 }
1035 #endif
1036
1037         if (buf == MAP_FAILED) {
1038                 return NULL;
1039         }
1040
1041         hdr = (struct anonymous_shared_header *)buf;
1042         hdr->u.length = bufsz;
1043
1044         ptr = (void *)(&hdr[1]);
1045
1046         return ptr;
1047 }
1048
1049 void *anonymous_shared_resize(void *ptr, size_t new_size, bool maymove)
1050 {
1051 #ifdef HAVE_MREMAP
1052         void *buf;
1053         size_t pagesz = getpagesize();
1054         size_t pagecnt;
1055         size_t bufsz;
1056         struct anonymous_shared_header *hdr;
1057         int flags = 0;
1058
1059         if (ptr == NULL) {
1060                 errno = EINVAL;
1061                 return NULL;
1062         }
1063
1064         hdr = (struct anonymous_shared_header *)ptr;
1065         hdr--;
1066         if (hdr->u.length > (new_size + sizeof(*hdr))) {
1067                 errno = EINVAL;
1068                 return NULL;
1069         }
1070
1071         bufsz = new_size + sizeof(*hdr);
1072
1073         /* round up to full pages */
1074         pagecnt = bufsz / pagesz;
1075         if (bufsz % pagesz) {
1076                 pagecnt += 1;
1077         }
1078         bufsz = pagesz * pagecnt;
1079
1080         if (new_size >= bufsz) {
1081                 /* integer wrap */
1082                 errno = ENOSPC;
1083                 return NULL;
1084         }
1085
1086         if (bufsz <= hdr->u.length) {
1087                 return ptr;
1088         }
1089
1090         if (maymove) {
1091                 flags = MREMAP_MAYMOVE;
1092         }
1093
1094         buf = mremap(hdr, hdr->u.length, bufsz, flags);
1095
1096         if (buf == MAP_FAILED) {
1097                 errno = ENOSPC;
1098                 return NULL;
1099         }
1100
1101         hdr = (struct anonymous_shared_header *)buf;
1102         hdr->u.length = bufsz;
1103
1104         ptr = (void *)(&hdr[1]);
1105
1106         return ptr;
1107 #else
1108         errno = ENOSPC;
1109         return NULL;
1110 #endif
1111 }
1112
1113 void anonymous_shared_free(void *ptr)
1114 {
1115         struct anonymous_shared_header *hdr;
1116
1117         if (ptr == NULL) {
1118                 return;
1119         }
1120
1121         hdr = (struct anonymous_shared_header *)ptr;
1122
1123         hdr--;
1124
1125         munmap(hdr, hdr->u.length);
1126 }
1127
1128 #ifdef DEVELOPER
1129 /* used when you want a debugger started at a particular point in the
1130    code. Mostly useful in code that runs as a child process, where
1131    normal gdb attach is harder to organise.
1132 */
1133 void samba_start_debugger(void)
1134 {
1135         char *cmd = NULL;
1136         if (asprintf(&cmd, "xterm -e \"gdb --pid %u\"&", getpid()) == -1) {
1137                 return;
1138         }
1139         if (system(cmd) == -1) {
1140                 free(cmd);
1141                 return;
1142         }
1143         free(cmd);
1144         sleep(2);
1145 }
1146 #endif