src/dps8/utfile.c

/* */
This source file includes following definitions.
hash32s
utfile_mkstemps
   1 /*
   2  * vim: filetype=c:tabstop=4:ai:expandtab
   3  * SPDX-License-Identifier: ICU
   4  * scspell-id: 485f7d3b-f630-11ec-953b-80ee73e9b8e7
   5  *
   6  * ---------------------------------------------------------------------------
   7  *
   8  * Copyright (c) 2021-2025 The DPS8M Development Team
   9  *
  10  * This software is made available under the terms of the ICU License.
  11  * See the LICENSE.md file at the top-level directory of this distribution.
  12  *
  13  * ---------------------------------------------------------------------------
  14  */
  15 
  16 #include <ctype.h>
  17 #include <signal.h>
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #if defined(__sunos) && defined(SYSV)
  24 # include <sys/param.h>
  25 #endif /* if defined(__sunos) && defined(SYSV) */
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <time.h>
  29 #include <sys/time.h>
  30 #include <stdint.h>
  31 #include <unistd.h>
  32 #include "dps8_sir.h"
  33 
  34 #define MAX_MKSTEMPS_TRIES 10000
  35 
  36 #if defined(__MINGW64__) || defined(__MINGW32__)
  37 # include "bsd_random.h"
  38 # define random  bsd_random
  39 # define srandom bsd_srandom
  40 #endif /* if defined(__MINGW64__) || defined(__MINGW32__) */
  41 
  42 #if defined(FREE)
  43 # undef FREE
  44 #endif /* if defined(FREE) */
  45 #define FREE(p) do  \
  46   {                 \
  47     free((p));      \
  48     (p) = NULL;     \
  49   } while(0)
  50 
  51 static char valid_file_name_chars[]
  52   = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  53 
  54 static inline uint32_t
  55 hash32s(const void *buf, size_t len, uint32_t h)
     /*  */
  56 {
  57   const unsigned char *p = buf;
  58 
  59   for (size_t i = 0; i < len; i++)
  60     h = h * 31 + p[i];
  61 
  62   h ^= h >> 17;
  63   h *= UINT32_C(0xed5ad4bb);
  64   h ^= h >> 11;
  65   h *= UINT32_C(0xac4c1b51);
  66   h ^= h >> 15;
  67   h *= UINT32_C(0x31848bab);
  68   h ^= h >> 14;
  69 
  70   return h;
  71 }
  72 
  73  /*
  74   * This is a minimal portable replacement for the mkstemps
  75   * function, which is not available on all platforms.
  76   */
  77 
  78 int
  79 utfile_mkstemps(char *request_pattern, int suffix_length)
     /*  */
  80 {
  81   long pattern_length;
  82   int st1ret;
  83   char *mask_pointer;
  84   struct timespec st1;
  85 
  86   char *pattern = strdup(request_pattern);
  87   if (!pattern)
  88     {
  89       (void)fprintf (stderr, "\rFATAL: Out of memory! Aborting at %s[%s:%d]\r\n",
  90                      __func__, __FILE__, __LINE__);
  91 #if defined(USE_BACKTRACE)
  92 # if defined(SIGUSR2)
  93       (void)raise(SIGUSR2);
  94       /*NOTREACHED*/ /* unreachable */
  95 # endif /* if defined(SIGUSR2) */
  96 #endif /* if defined(USE_BACKTRACE) */
  97       abort();
  98     }
  99 
 100   pattern_length = (long) strlen(pattern);
 101 
 102   st1ret = clock_gettime(SIR_WALLCLOCK, &st1);
 103   if (st1ret != 0)
 104     {
 105       (void)fprintf (stderr, "\rFATAL: clock_gettime failure! Aborting at %s[%s:%d]\r\n",
 106                      __func__, __FILE__, __LINE__);
 107 #if defined(USE_BACKTRACE)
 108 # if defined(SIGUSR2)
 109       (void)raise(SIGUSR2);
 110       /*NOTREACHED*/ /* unreachable */
 111 # endif /* if defined(SIGUSR2) */
 112 #endif /* if defined(USE_BACKTRACE) */
 113       abort();
 114     }
 115 
 116   uint32_t h = 0;  /* initial hash value */
 117 #if __STDC_VERSION__ < 201112L
 118   /* LINTED E_OLD_STYLE_FUNC_DECL */
 119   void *(*mallocptr)() = malloc;
 120   h = hash32s(&mallocptr, sizeof(mallocptr), h);
 121 #endif /* if __STDC_VERSION__ < 201112L */
 122   void *ptr = &ptr;
 123   h = hash32s(&ptr, sizeof(ptr), h);
 124   time_t t = time(0);
 125   h = hash32s(&t, sizeof(t), h);
 126 #if !defined(_AIX) && !defined(__managarm__)
 127   for (int i = 0; i < 1000; i++)
 128     {
 129       unsigned long counter = 0;
 130       clock_t start = clock();
 131       while (clock() == start)
 132         {
 133           counter++;
 134         }
 135       h = hash32s(&start, sizeof(start), h);
 136       h = hash32s(&counter, sizeof(counter), h);
 137     }
 138 #endif /* if !defined(_AIX) */
 139   int mypid = (int)_sir_getpid();
 140   h = hash32s(&mypid, sizeof(mypid), h);
 141   char rnd[4];
 142   FILE *f = fopen("/dev/urandom", "rb");
 143   if (f)
 144     {
 145       if (fread(rnd, sizeof(rnd), 1, f))
 146         {
 147           h = hash32s(rnd, sizeof(rnd), h);
 148         }
 149       fclose(f);
 150     }
 151   srandom(h);
 152 
 153   if (( (long) pattern_length - 6 ) < (long) suffix_length)
 154   {
 155     FREE(pattern);
 156     return ( -1 );
 157   }
 158 
 159   long mask_offset = (long) pattern_length - ( 6 + (long) suffix_length );
 160 
 161   if (strncmp(&pattern[mask_offset], "XXXXXX", 6))
 162   {
 163     FREE(pattern);
 164     return ( -1 );
 165   }
 166 
 167   mask_pointer = &pattern[mask_offset];
 168 
 169   long valid_char_count = (long) strlen(valid_file_name_chars);
 170 
 171   if (valid_char_count < 1)
 172     {
 173       FREE(pattern);
 174       return ( -1 );
 175     }
 176 
 177   for (int count = 0; count < MAX_MKSTEMPS_TRIES; count++)
 178   {
 179     for (int mask_index = 0; mask_index < 6; mask_index++)
 180     {
 181       mask_pointer[mask_index]
 182         = valid_file_name_chars[random() % valid_char_count];
 183     }
 184 
 185     int fd = open(pattern, O_CREAT | O_RDWR | O_EXCL, S_IRUSR | S_IWUSR);
 186 
 187     if (fd >= 0)
 188     {
 189       FREE(pattern);
 190       return ( fd );
 191     }
 192 
 193     /*
 194      * If the error is not "file already exists",
 195      * or is a directory, then we just bail out.
 196      */
 197 
 198     if (( errno != EEXIST ) && ( errno != EISDIR ))
 199     {
 200       break;
 201     }
 202   }
 203 
 204   /*
 205    * If we get here, we were unable to create
 206    * a unique file name, despite many tries.
 207    */
 208 
 209   FREE(pattern);
 210   return ( -1 );
 211 }
/* */
root/src/dps8/utfile.c

DEFINITIONS
