diff options
Diffstat (limited to 'sysdeps/posix/mktemp.c')
| -rw-r--r-- | sysdeps/posix/mktemp.c | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/sysdeps/posix/mktemp.c b/sysdeps/posix/mktemp.c index f7a1783..6bbc4c0 100644 --- a/sysdeps/posix/mktemp.c +++ b/sysdeps/posix/mktemp.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1993, 1996 Free Software Foundation, Inc. +/* Copyright (C) 1991, 1992, 1993, 1996, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,13 +16,15 @@ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ +#include <errno.h> +#include <stdint.h> +#include <stdio.h> #include <stdlib.h> #include <string.h> -#include <errno.h> #include <unistd.h> -#include <stdio.h> -#include <sys/types.h> #include <sys/stat.h> +#include <sys/time.h> +#include <sys/types.h> /* Generate a unique temporary file name from TEMPLATE. The last six characters of TEMPLATE must be "XXXXXX"; @@ -33,8 +35,11 @@ mktemp (template) { static const char letters[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; + static uint32_t value; + struct timeval tv; + char *XXXXXX; size_t len; - size_t i; + int count; len = strlen (template); if (len < 6 || strcmp (&template[len - 6], "XXXXXX")) @@ -43,20 +48,39 @@ mktemp (template) return NULL; } - if (sprintf (&template[len - 5], "%.5u", - (unsigned int) getpid () % 100000) != 5) - /* Inconceivable lossage. */ - return NULL; + /* This is where the Xs start. */ + XXXXXX = &template[len - 6]; - for (i = 0; i < sizeof (letters); ++i) + /* Get some more or less random data. */ + __gettimeofday (&tv, NULL); + value += tv.tv_usec | getpid (); + + for (count = 0; count < TMP_MAX; ++count) { struct stat ignored; + uint32_t v = value; - template[len - 6] = letters[i]; + /* Fill in the random bits. */ + XXXXXX[0] = letters[v % 62]; + v /= 62; + XXXXXX[1] = letters[v % 62]; + v /= 62; + XXXXXX[2] = letters[v % 62]; + v /= 62; + XXXXXX[3] = letters[v % 62]; + v /= 62; + XXXXXX[4] = letters[v % 62]; + v /= 62; + XXXXXX[5] = letters[v % 62]; if (stat (template, &ignored) < 0 && errno == ENOENT) /* The file does not exist. So return this name. */ return template; + + /* This is a random value. It is only necessary that the next + TMP_MAX values generated by adding 7777 to VALUE are different + with (module 2^32). */ + value += 7777; } /* We return the null string if we can't find a unique file name. */ |