gl/lib/tempname.c.diff

   1 diff --git c/lib/tempname.c i/lib/tempname.c
   2 index 2da5afe..562955a 100644
   3 --- c/lib/tempname.c
   4 +++ i/lib/tempname.c
   5 @@ -22,6 +22,7 @@
   6  #if !_LIBC
   7  # include <config.h>
   8  # include "tempname.h"
   9 +# include "randint.h"
  10  #endif
  11
  12  #include <sys/types.h>
  13 @@ -49,6 +50,7 @@
  14  # error report this to bug-gnulib@gnu.org
  15  #endif
  16
  17 +#include <stdbool.h>
  18  #include <stddef.h>
  19  #include <stdlib.h>
  20  #include <string.h>
  21 @@ -179,14 +181,21 @@ __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
  22  }
  23  #endif /* _LIBC */
  24
  25 +static inline bool _GL_ATTRIBUTE_PURE
  26 +check_x_suffix (char const *s, size_t len)
  27 +{
  28 +  return len <= strspn (s, "X");
  29 +}
  30 +
  31  /* These are the characters used in temporary file names.  */
  32  static const char letters[] =
  33  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
  34
  35  /* Generate a temporary file name based on TMPL.  TMPL must match the
  36 -   rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
  37 +   rules for mk[s]temp (i.e. end in at least X_SUFFIX_LEN "X"s,
  38 +   possibly with a suffix).
  39     The name constructed does not exist at the time of the call to
  40 -   __gen_tempname.  TMPL is overwritten with the result.
  41 +   this function.  TMPL is overwritten with the result.
  42
  43     KIND may be one of:
  44     __GT_NOCREATE:      simply verify that the name does not exist
  45 @@ -197,23 +206,24 @@ static const char letters[] =
  46
  47     We use a clever algorithm to get hard-to-predict names. */
  48  int
  49 -__gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
  50 +gen_tempname_len (char *tmpl, int suffixlen, int flags, int kind,
  51 +                  size_t x_suffix_len)
  52  {
  53 -  int len;
  54 +  size_t len;
  55    char *XXXXXX;
  56 -  static uint64_t value;
  57 -  uint64_t random_time_bits;
  58    unsigned int count;
  59    int fd = -1;
  60    int save_errno = errno;
  61    struct_stat64 st;
  62 +  struct randint_source *rand_src;
  63
  64    /* A lower bound on the number of temporary files to attempt to
  65       generate.  The maximum total number of temporary file names that
  66       can exist for a given template is 62**6.  It should never be
  67       necessary to try all these combinations.  Instead if a reasonable
  68       number of names is tried (we define reasonable as 62**3) fail to
  69 -     give the system administrator the chance to remove the problems.  */
  70 +     give the system administrator the chance to remove the problems.
  71 +     This value requires that X_SUFFIX_LEN be at least 3.  */
  72  #define ATTEMPTS_MIN (62 * 62 * 62)
  73
  74    /* The number of times to attempt to generate a temporary file.  To
  75 @@ -225,43 +235,28 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
  76  #endif
  77
  78    len = strlen (tmpl);
  79 -  if (len < 6 + suffixlen || memcmp (&tmpl[len - 6 - suffixlen], "XXXXXX", 6))
  80 +  if (len < x_suffix_len + suffixlen
  81 +      || ! check_x_suffix (&tmpl[len - x_suffix_len - suffixlen],
  82 +                           x_suffix_len))
  83      {
  84        __set_errno (EINVAL);
  85        return -1;
  86      }
  87
  88    /* This is where the Xs start.  */
  89 -  XXXXXX = &tmpl[len - 6 - suffixlen];
  90 +  XXXXXX = &tmpl[len - x_suffix_len - suffixlen];
  91
  92    /* Get some more or less random data.  */
  93 -#ifdef RANDOM_BITS
  94 -  RANDOM_BITS (random_time_bits);
  95 -#else
  96 -  {
  97 -    struct timeval tv;
  98 -    __gettimeofday (&tv, NULL);
  99 -    random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
 100 -  }
 101 -#endif
 102 -  value += random_time_bits ^ __getpid ();
 103 +  rand_src = randint_all_new (NULL, x_suffix_len);
 104 +  if (! rand_src)
 105 +    return -1;
 106
 107 -  for (count = 0; count < attempts; value += 7777, ++count)
 108 +  for (count = 0; count < attempts; ++count)
 109      {
 110 -      uint64_t v = value;
 111 -
 112 -      /* Fill in the random bits.  */
 113 -      XXXXXX[0] = letters[v % 62];
 114 -      v /= 62;
 115 -      XXXXXX[1] = letters[v % 62];
 116 -      v /= 62;
 117 -      XXXXXX[2] = letters[v % 62];
 118 -      v /= 62;
 119 -      XXXXXX[3] = letters[v % 62];
 120 -      v /= 62;
 121 -      XXXXXX[4] = letters[v % 62];
 122 -      v /= 62;
 123 -      XXXXXX[5] = letters[v % 62];
 124 +      size_t i;
 125 +
 126 +      for (i = 0; i < x_suffix_len; i++)
 127 +        XXXXXX[i] = letters[randint_genmax (rand_src, sizeof letters - 2)];
 128
 129        switch (kind)
 130          {
 131 @@ -276,7 +271,7 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
 132            break;
 133
 134          case __GT_NOCREATE:
 135 -          /* This case is backward from the other three.  __gen_tempname
 136 +          /* This case is backward from the other three.  This function
 137               succeeds if __xstat fails because the name does not exist.
 138               Note the continue to bypass the common logic at the bottom
 139               of the loop.  */
 140 @@ -285,11 +280,15 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
 141                if (errno == ENOENT)
 142                  {
 143                    __set_errno (save_errno);
 144 -                  return 0;
 145 +                  fd = 0;
 146 +                  goto done;
 147                  }
 148                else
 149 -                /* Give up now. */
 150 -                return -1;
 151 +                {
 152 +                  /* Give up now. */
 153 +                  fd = -1;
 154 +                  goto done;
 155 +                }
 156              }
 157            continue;
 158
 159 @@ -301,13 +300,32 @@ __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
 160        if (fd >= 0)
 161          {
 162            __set_errno (save_errno);
 163 -          return fd;
 164 +          goto done;
 165          }
 166        else if (errno != EEXIST)
 167 -        return -1;
 168 +        {
 169 +          fd = -1;
 170 +          goto done;
 171 +        }
 172      }
 173
 174 +  randint_all_free (rand_src);
 175 +
 176    /* We got out of the loop because we ran out of combinations to try.  */
 177    __set_errno (EEXIST);
 178    return -1;
 179 +
 180 + done:
 181 +  {
 182 +    int saved_errno = errno;
 183 +    randint_all_free (rand_src);
 184 +    __set_errno (saved_errno);
 185 +  }
 186 +  return fd;
 187 +}
 188 +
 189 +int
 190 +__gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
 191 +{
 192 +  return gen_tempname_len (tmpl, suffixlen, flags, kind, 6);
 193  }