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 *small = malloc(1);
 123   h = hash32s(&small, sizeof(small), h);
 124   FREE(small);
 125   void *big = malloc(1UL << 20);
 126   h = hash32s(&big, sizeof(big), h);
 127   FREE(big);
 128   void *ptr = &ptr;
 129   h = hash32s(&ptr, sizeof(ptr), h);
 130   time_t t = time(0);
 131   h = hash32s(&t, sizeof(t), h);
 132 #if !defined(_AIX)
 133   for (int i = 0; i < 1000; i++)
 134     {
 135       unsigned long counter = 0;
 136       clock_t start = clock();
 137       while (clock() == start)
 138         {
 139           counter++;
 140         }
 141       h = hash32s(&start, sizeof(start), h);
 142       h = hash32s(&counter, sizeof(counter), h);
 143     }
 144 #endif /* if !defined(_AIX) */
 145   int mypid = (int)getpid();
 146   h = hash32s(&mypid, sizeof(mypid), h);
 147   char rnd[4];
 148   FILE *f = fopen("/dev/urandom", "rb");
 149   if (f)
 150     {
 151       if (fread(rnd, sizeof(rnd), 1, f))
 152         {
 153           h = hash32s(rnd, sizeof(rnd), h);
 154         }
 155       fclose(f);
 156     }
 157   srandom(h);
 158 
 159   if (( (long) pattern_length - 6 ) < (long) suffix_length)
 160   {
 161     FREE(pattern);
 162     return ( -1 );
 163   }
 164 
 165   long mask_offset = (long) pattern_length - ( 6 + (long) suffix_length );
 166 
 167   if (strncmp(&pattern[mask_offset], "XXXXXX", 6))
 168   {
 169     FREE(pattern);
 170     return ( -1 );
 171   }
 172 
 173   mask_pointer = &pattern[mask_offset];
 174 
 175   long valid_char_count = (long) strlen(valid_file_name_chars);
 176 
 177   if (valid_char_count < 1)
 178     {
 179       FREE(pattern);
 180       return ( -1 );
 181     }
 182 
 183   for (int count = 0; count < MAX_MKSTEMPS_TRIES; count++)
 184   {
 185     for (int mask_index = 0; mask_index < 6; mask_index++)
 186     {
 187       mask_pointer[mask_index]
 188         = valid_file_name_chars[random() % valid_char_count];
 189     }
 190 
 191     int fd = open(pattern, O_CREAT | O_RDWR | O_EXCL, S_IRUSR | S_IWUSR);
 192 
 193     if (fd >= 0)
 194     {
 195       FREE(pattern);
 196       return ( fd );
 197     }
 198 
 199     /*
 200      * If the error is not "file already exists",
 201      * or is a directory, then we just bail out.
 202      */
 203 
 204     if (( errno != EEXIST ) && ( errno != EISDIR ))
 205     {
 206       break;
 207     }
 208   }
 209 
 210   /*
 211    * If we get here, we were unable to create
 212    * a unique file name, despite many tries.
 213    */
 214 
 215   FREE(pattern);
 216   return ( -1 );
 217 }
/* */
root/src/dps8/utfile.c

DEFINITIONS
