string.c

   1 /*
   2  * Copyright (C) 2004-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file string.c Memory allocation and string handling functions. */
   8
   9 #include "para.h"
  10 #include "string.h"
  11
  12 #include <sys/time.h> /* gettimeofday */
  13 #include <pwd.h>
  14 #include <sys/utsname.h> /* uname() */
  15 #include <string.h>
  16
  17 #include "error.h"
  18
  19 /**
  20  * Paraslash's version of realloc().
  21  *
  22  * \param p Pointer to the memory block, may be \p NULL.
  23  * \param size The desired new size.
  24  *
  25  * A wrapper for realloc(3). It calls \p exit(\p EXIT_FAILURE) on errors,
  26  * i.e. there is no need to check the return value in the caller.
  27  *
  28  * \return A pointer to  the newly allocated memory, which is suitably aligned
  29  * for any kind of variable and may be different from \a p.
  30  *
  31  * \sa realloc(3).
  32  */
  33 __must_check __malloc void *para_realloc(void *p, size_t size)
  34 {
  35         /*
  36          * No need to check for NULL pointers: If p is NULL, the  call
  37          * to realloc is equivalent to malloc(size)
  38          */
  39         assert(size);
  40         if (!(p = realloc(p, size))) {
  41                 PARA_EMERG_LOG("realloc failed (size = %zu), aborting\n",
  42                         size);
  43                 exit(EXIT_FAILURE);
  44         }
  45         return p;
  46 }
  47
  48 /**
  49  * Paraslash's version of malloc().
  50  *
  51  * \param size The desired new size.
  52  *
  53  * A wrapper for malloc(3) which exits on errors.
  54  *
  55  * \return A pointer to the allocated memory, which is suitably aligned for any
  56  * kind of variable.
  57  *
  58  * \sa malloc(3).
  59  */
  60 __must_check __malloc void *para_malloc(size_t size)
  61 {
  62         assert(size);
  63         void *p = malloc(size);
  64
  65         if (!p) {
  66                 PARA_EMERG_LOG("malloc failed (size = %zu),  aborting\n",
  67                         size);
  68                 exit(EXIT_FAILURE);
  69         }
  70         return p;
  71 }
  72
  73 /**
  74  * Paraslash's version of calloc().
  75  *
  76  * \param size The desired new size.
  77  *
  78  * A wrapper for calloc(3) which exits on errors.
  79  *
  80  * \return A pointer to the allocated and zeroed-out memory, which is suitably
  81  * aligned for any kind of variable.
  82  *
  83  * \sa calloc(3)
  84  */
  85 __must_check __malloc void *para_calloc(size_t size)
  86 {
  87         void *ret = para_malloc(size);
  88
  89         memset(ret, 0, size);
  90         return ret;
  91 }
  92
  93 /**
  94  * Paraslash's version of strdup().
  95  *
  96  * \param s The string to be duplicated.
  97  *
  98  * A wrapper for strdup(3). It calls \p exit(EXIT_FAILURE) on errors, i.e.
  99  * there is no need to check the return value in the caller.
 100  *
 101  * \return A pointer to the duplicated string. If \p s was the NULL pointer,
 102  * an pointer to an empty string is returned.
 103  *
 104  * \sa strdup(3)
 105  */
 106 __must_check __malloc char *para_strdup(const char *s)
 107 {
 108         char *ret;
 109
 110         if ((ret = strdup(s? s: "")))
 111                 return ret;
 112         PARA_EMERG_LOG("strdup failed, aborting\n");
 113         exit(EXIT_FAILURE);
 114 }
 115
 116 /**
 117  * Allocate a sufficiently large string and print into it.
 118  *
 119  * \param fmt A usual format string.
 120  *
 121  * Produce output according to \p fmt. No artificial bound on the length of the
 122  * resulting string is imposed.
 123  *
 124  * \return This function either returns a pointer to a string that must be
 125  * freed by the caller or aborts without returning.
 126  *
 127  * \sa printf(3).
 128  */
 129 __must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
 130 {
 131         char *msg;
 132
 133         PARA_VSPRINTF(fmt, msg);
 134         return msg;
 135 }
 136
 137 /**
 138  * Paraslash's version of strcat().
 139  *
 140  * \param a String to be appended to.
 141  * \param b String to append.
 142  *
 143  * Append \p b to \p a.
 144  *
 145  * \return If \a a is \p NULL, return a pointer to a copy of \a b, i.e.
 146  * para_strcat(NULL, b) is equivalent to para_strdup(b). If \a b is \p NULL,
 147  * return \a a without making a copy of \a a.  Otherwise, construct the
 148  * concatenation \a c, free \a a (but not \a b) and return \a c.
 149  *
 150  * \sa strcat(3)
 151  */
 152 __must_check __malloc char *para_strcat(char *a, const char *b)
 153 {
 154         char *tmp;
 155
 156         if (!a)
 157                 return para_strdup(b);
 158         if (!b)
 159                 return a;
 160         tmp = make_message("%s%s", a, b);
 161         free(a);
 162         return tmp;
 163 }
 164
 165 /**
 166  * Paraslash's version of dirname().
 167  *
 168  * \param name Pointer to the full path.
 169  *
 170  * Compute the directory component of \p name.
 171  *
 172  * \return If \a name is \p NULL or the empty string, return \p NULL.
 173  * Otherwise, Make a copy of \a name and return its directory component. Caller
 174  * is responsible to free the result.
 175  */
 176 __must_check __malloc char *para_dirname(const char *name)
 177 {
 178         char *p, *ret;
 179
 180         if (!name || !*name)
 181                 return NULL;
 182         ret = para_strdup(name);
 183         p = strrchr(ret, '/');
 184         if (!p)
 185                 *ret = '\0';
 186         else
 187                 *p = '\0';
 188         return ret;
 189 }
 190
 191 /**
 192  * Paraslash's version of basename().
 193  *
 194  * \param name Pointer to the full path.
 195  *
 196  * Compute the filename component of \a name.
 197  *
 198  * \return \p NULL if (a) \a name is the empty string or \p NULL, or (b) name
 199  * ends with a slash.  Otherwise, a pointer within \a name is returned.  Caller
 200  * must not free the result.
 201  */
 202 __must_check const char *para_basename(const char *name)
 203 {
 204         const char *ret;
 205
 206         if (!name || !*name)
 207                 return NULL;
 208         ret = strrchr(name, '/');
 209         if (!ret)
 210                 return name;
 211         ret++;
 212         return ret;
 213 }
 214
 215 /**
 216  * Cut trailing newline.
 217  *
 218  * \param buf The string to be chopped.
 219  *
 220  * Replace the last character in \p buf by zero if it is euqal to
 221  * the newline character.
 222  */
 223 void chop(char *buf)
 224 {
 225         int n = strlen(buf);
 226         if (!n)
 227                 return;
 228         if (buf[n - 1] == '\n')
 229                 buf[n - 1] = '\0';
 230 }
 231
 232 /**
 233  * Get a random filename.
 234  *
 235  * This is by no means a secure way to create temporary files in a hostile
 236  * direcory like \p /tmp. However, it is OK to use for temp files, fifos,
 237  * sockets that are created in ~/.paraslash. Result must be freed by the
 238  * caller.
 239  *
 240  * \return A pointer to a random filename.
 241  */
 242 __must_check __malloc char *para_tmpname(void)
 243 {
 244         struct timeval now;
 245         unsigned int seed;
 246
 247         gettimeofday(&now, NULL);
 248         seed = now.tv_usec;
 249         srand(seed);
 250         return make_message("%08i", rand());
 251 }
 252
 253 /**
 254  * Get the logname of the current user.
 255  *
 256  * \return A dynammically allocated string that must be freed by the caller. On
 257  * errors, the string "unknown user" is returned, i.e. this function never
 258  * returns \p NULL.
 259  *
 260  * \sa getpwuid(3).
 261  */
 262 __must_check __malloc char *para_logname(void)
 263 {
 264         struct passwd *pw = getpwuid(getuid());
 265         return para_strdup(pw? pw->pw_name : "unknown_user");
 266 }
 267
 268 /**
 269  * Get the home directory of the current user.
 270  *
 271  * \return A dynammically allocated string that must be freed by the caller. If
 272  * the home directory could not be found, this function returns "/tmp".
 273  */
 274 __must_check __malloc char *para_homedir(void)
 275 {
 276         struct passwd *pw = getpwuid(getuid());
 277         return para_strdup(pw? pw->pw_dir : "/tmp");
 278 }
 279
 280 /**
 281  * Split string and return pointers to its parts.
 282  *
 283  * \param args The string to be split.
 284  * \param argv_ptr Pointer to the list of substrings.
 285  * \param delim Delimiter.
 286  *
 287  * This function modifies \a args by replacing each occurance of \a delim by
 288  * zero. A \p NULL-terminated array of pointers to char* is allocated dynamically
 289  * and these pointers are initialized to point to the broken-up substrings
 290  * within \a args. A pointer to this array is returned via \a argv_ptr.
 291  *
 292  * \return The number of substrings found in \a args.
 293  */
 294 __must_check unsigned split_args(char *args, char *** const argv_ptr, const char *delim)
 295 {
 296         char *p = args;
 297         char **argv;
 298         size_t n = 0, i, j;
 299
 300         p = args + strspn(args, delim);
 301         for (;;) {
 302                 i = strcspn(p, delim);
 303                 if (!i)
 304                         break;
 305                 p += i;
 306                 n++;
 307                 p += strspn(p, delim);
 308         }
 309         *argv_ptr = para_malloc((n + 1) * sizeof(char *));
 310         argv = *argv_ptr;
 311         i = 0;
 312         p = args + strspn(args, delim);
 313         while (p) {
 314                 argv[i] = p;
 315                 j = strcspn(p, delim);
 316                 if (!j)
 317                         break;
 318                 p += strcspn(p, delim);
 319                 if (*p) {
 320                         *p = '\0';
 321                         p++;
 322                         p += strspn(p, delim);
 323                 }
 324                 i++;
 325         }
 326         argv[n] = NULL;
 327         return n;
 328 }
 329
 330 /**
 331  * Ensure that file descriptors 0, 1, and 2 are valid.
 332  *
 333  * Common approach that opens /dev/null until it gets a file descriptor greater
 334  * than two.
 335  *
 336  * \sa okir's Black Hats Manual.
 337  */
 338 void valid_fd_012(void)
 339 {
 340         while (1) {
 341                 int fd = open("/dev/null", O_RDWR);
 342                 if (fd < 0)
 343                         exit(EXIT_FAILURE);
 344                 if (fd > 2) {
 345                         close(fd);
 346                         break;
 347                 }
 348         }
 349 }
 350
 351 /**
 352  * Get the own hostname.
 353  *
 354  * \return A dynammically allocated string containing the hostname.
 355  *
 356  * \sa uname(2).
 357  */
 358 __malloc char *para_hostname(void)
 359 {
 360         struct utsname u;
 361
 362         uname(&u);
 363         return para_strdup(u.nodename);
 364 }
 365
 366 /**
 367  * Used to distinguish between read-only and read-write mode.
 368  *
 369  * \sa for_each_line(), for_each_line_ro().
 370  */
 371 enum for_each_line_modes{
 372         /** Activate read-only mode. */
 373         LINE_MODE_RO,
 374         /** Activate read-write mode. */
 375         LINE_MODE_RW
 376 };
 377
 378 static int for_each_complete_line(enum for_each_line_modes mode, char *buf,
 379                 size_t size, line_handler_t *line_handler, void *private_data)
 380 {
 381         char *start = buf, *end;
 382         int ret, i, num_lines = 0;
 383
 384 //      PARA_NOTICE_LOG("buf: %s\n", buf);
 385         while (start < buf + size) {
 386                 char *next_null;
 387                 char *next_cr;
 388
 389                 next_cr = memchr(start, '\n', buf + size - start);
 390                 next_null = memchr(start, '\0', buf + size - start);
 391                 if (!next_cr && !next_null)
 392                         break;
 393                 if (next_cr && next_null) {
 394                         end = next_cr < next_null? next_cr : next_null;
 395                 } else if (next_null) {
 396                         end = next_null;
 397                 } else
 398                         end = next_cr;
 399                 num_lines++;
 400                 if (!line_handler) {
 401                         start = ++end;
 402                         continue;
 403                 }
 404                 if (mode == LINE_MODE_RO) {
 405                         size_t s = end - start;
 406                         char *b = para_malloc(s + 1);
 407                         memcpy(b, start, s);
 408                         b[s] = '\0';
 409 //                      PARA_NOTICE_LOG("b: %s, start: %s\n", b, start);
 410                         ret = line_handler(b, private_data);
 411                         free(b);
 412                 } else {
 413                         *end = '\0';
 414                         ret = line_handler(start, private_data);
 415                 }
 416                 if (ret < 0)
 417                         return ret;
 418                 start = ++end;
 419         }
 420         if (!line_handler || mode == LINE_MODE_RO)
 421                 return num_lines;
 422         i = buf + size - start;
 423         if (i && i != size)
 424                 memmove(buf, start, i);
 425         return i;
 426 }
 427
 428 /**
 429  * Call a custom function for each complete line.
 430  *
 431  * \param buf The buffer containing data seperated by newlines.
 432  * \param size The number of bytes in \a buf.
 433  * \param line_handler The custom function.
 434  * \param private_data Pointer passed to \a line_handler.
 435  *
 436  * If \p line_handler is \p NULL, the function returns the number of complete
 437  * lines in \p buf.  Otherwise, \p line_handler is called for each complete
 438  * line in \p buf.  The first argument to \p line_handler is the current line,
 439  * and \p private_data is passed as the second argument.  The function returns
 440  * if \p line_handler returns a negative value or no more lines are in the
 441  * buffer.  The rest of the buffer (last chunk containing an incomplete line)
 442  * is moved to the beginning of the buffer.
 443  *
 444  * \return If \p line_handler is not \p NULL, this function returns the number
 445  * of bytes not handled to \p line_handler on success, or the negative return
 446  * value of the \p line_handler on errors.
 447  *
 448  * \sa for_each_line_ro().
 449  */
 450 int for_each_line(char *buf, size_t size, line_handler_t *line_handler,
 451                 void *private_data)
 452 {
 453         return for_each_complete_line(LINE_MODE_RW, buf, size, line_handler,
 454                 private_data);
 455 }
 456
 457 /**
 458  * Call a custom function for each complete line.
 459  *
 460  * \param buf Same meaning as in \p for_each_line().
 461  * \param size Same meaning as in \p for_each_line().
 462  * \param line_handler Same meaning as in \p for_each_line().
 463  * \param private_data Same meaning as in \p for_each_line().
 464  *
 465  * This function behaves like \p for_each_line(), but \a buf is left unchanged.
 466  *
 467  * \return On success, the function returns the number of complete lines in \p
 468  * buf, otherwise the (negative) return value of \p line_handler is returned.
 469  *
 470  * \sa for_each_line().
 471  */
 472 int for_each_line_ro(char *buf, size_t size, line_handler_t *line_handler,
 473                 void *private_data)
 474 {
 475         return for_each_complete_line(LINE_MODE_RO, buf, size, line_handler,
 476                 private_data);
 477 }
 478
 479 /**
 480  * Safely print into a buffer at a given offset
 481  *
 482  * \param b Determines the buffer, its size, and the offset.
 483  * \param fmt The format string.
 484  *
 485  * This function prints into the buffer given by \a b at the offset which is
 486  * also given by \a b. If there is not enough space to hold the result, the
 487  * buffer size is doubled until the underlying call to vsnprintf() succeeds
 488  * or the size of the buffer exceeds the maximal size specified in \a pb.
 489  *
 490  * In the latter case the unmodified \a buf and \a offset values as well as the
 491  * private_data pointer of \a b are passed to the \a max_size_handler of \a b.
 492  * If this function succeeds, i.e. returns a non-negative value, the offset of
 493  * \a b is reset to zero and the given data is written to the beginning of the
 494  * buffer.
 495  *
 496  * Upon return, the offset of \a b is adjusted accordingly so that subsequent
 497  * calls to this function append data to what is already contained in the
 498  * buffer.
 499  *
 500  * It's OK to call this function with \p b->buf being \p NULL. In this case, an
 501  * initial buffer is allocated.
 502  *
 503  * \return The number of bytes printed into the buffer (not including the
 504  * therminating \p NULL byte).
 505  *
 506  * \sa make_message(), vsnprintf(3).
 507  */
 508 __printf_2_3 int para_printf(struct para_buffer *b, const char *fmt, ...)
 509 {
 510         int ret;
 511
 512         if (!b->buf) {
 513                 b->buf = para_malloc(128);
 514                 b->size = 128;
 515                 b->offset = 0;
 516         }
 517         while (1) {
 518                 char *p = b->buf + b->offset;
 519                 size_t size = b->size - b->offset;
 520                 va_list ap;
 521                 if (size) {
 522                         va_start(ap, fmt);
 523                         ret = vsnprintf(p, size, fmt, ap);
 524                         va_end(ap);
 525                         if (ret > -1 && ret < size) { /* success */
 526                                 b->offset += ret;
 527                                 return ret;
 528                         }
 529                 }
 530                 /* check if we may grow the buffer */
 531                 if (!b->max_size || 2 * b->size < b->max_size) { /* yes */
 532                         /* try again with more space */
 533                         b->size *= 2;
 534                         b->buf = para_realloc(b->buf, b->size);
 535                         continue;
 536                 }
 537                 /* can't grow buffer */
 538                 if (!b->offset || !b->max_size_handler) /* message too large */
 539                         return -ERRNO_TO_PARA_ERROR(ENOSPC);
 540                 ret = b->max_size_handler(b->buf, b->offset, b->private_data);
 541                 if (ret < 0)
 542                         return ret;
 543                 b->offset = 0;
 544         }
 545 }
 546
 547 /** \cond LLONG_MAX and LLONG_LIN might not be defined. */
 548 #ifndef LLONG_MAX
 549 #define LLONG_MAX (1 << (sizeof(long) - 1))
 550 #endif
 551 #ifndef LLONG_MIN
 552 #define LLONG_MIN (-LLONG_MAX - 1LL)
 553 #endif
 554 /** \endcond */
 555
 556 /**
 557  * Convert a string to a 64-bit signed integer value.
 558  *
 559  * \param str The string to be converted.
 560  * \param value Result pointer.
 561  *
 562  * \return Standard.
 563  *
 564  * \sa para_atoi32(), strtol(3), atoi(3).
 565  */
 566 int para_atoi64(const char *str, int64_t *value)
 567 {
 568         char *endptr;
 569         long long tmp;
 570
 571         errno = 0; /* To distinguish success/failure after call */
 572         tmp = strtoll(str, &endptr, 10);
 573         if (errno == ERANGE && (tmp == LLONG_MAX || tmp == LLONG_MIN))
 574                 return -E_ATOI_OVERFLOW;
 575         if (errno != 0 && tmp == 0) /* other error */
 576                 return -E_STRTOLL;
 577         if (endptr == str)
 578                 return -E_ATOI_NO_DIGITS;
 579         if (*endptr != '\0') /* Further characters after number */
 580                 return -E_ATOI_JUNK_AT_END;
 581         *value = tmp;
 582         return 1;
 583 }
 584
 585 /**
 586  * Convert a string to a 32-bit signed integer value.
 587  *
 588  * \param str The string to be converted.
 589  * \param value Result pointer.
 590  *
 591  * \return Standard.
 592  *
 593  * \sa para_atoi64().
 594 */
 595 int para_atoi32(const char *str, int32_t *value)
 596 {
 597         int64_t tmp;
 598         int ret;
 599         const int32_t max = 2147483647;
 600
 601         ret = para_atoi64(str, &tmp);
 602         if (ret < 0)
 603                 return ret;
 604         if (tmp > max || tmp < -max - 1)
 605                 return -E_ATOI_OVERFLOW;
 606         *value = tmp;
 607         return 1;
 608 }