[PATCH] STDCXX-1019 __rw_mkstemp in file.cpp should honor TMPDIR environment variable

[Scott Zhong]

Changelog:

* src/file.cpp (__rw_mkstemp): use TMPDIR variable from environment if
defined.

here is the patch:

Index: src/file.cpp
===================================================================
--- src/file.cpp        (revision 702657)
+++ src/file.cpp        (working copy)
@@ -42,6 +42,7 @@
 #include <stdio.h>    // for P_tmpdir, std{err,in,out}, tmpnam()
 #include <stdlib.h>   // for mkstemp(), strtoul(), size_t
 #include <ctype.h>    // for isalpha(), isspace(), toupper()
+#include <string.h>   // for memcpy()
 
 
 #if defined (_WIN32) && !defined (__CYGWIN__) @@ -58,6 +59,9 @@  #
define _BINARY 0  #endif
 
+#ifndef PATH_MAX
+#  define PATH_MAX   1024
+#endif
 
 #include <rw/_file.h>
 #include <rw/_defs.h>
@@ -257,8 +261,18 @@
 #    define P_tmpdir "/tmp"
 #  endif   // P_tmpdir
 
-    char fnamebuf[] = P_tmpdir "/.rwtmpXXXXXX";
+    const char *tmpdir = getenv ("TMPDIR");
+    if (tmpdir == NULL) { 
+        tmpdir = P_tmpdir;
+    }
 
+    char fnamebuf [PATH_MAX];
+
+    size_t len = strlen (tmpdir) - 1;
+ 
+    memcpy (fnamebuf, tmpdir, len);
+    memcpy (fnamebuf+len, "/.rwtmpXXXXXX", sizeof ("/.rwtmpXXXXXX"));
+
     fd = mkstemp (fnamebuf);
 
     if (fd >= 0)
@@ -294,7 +308,7 @@
     // names that have no extension. tempnam uses malloc to allocate
     // space for the filename; the program is responsible for freeing
     // this space when it is no longer needed. 
-    char* const fname = tempnam (P_tmpdir, ".rwtmp");
+    char* const fname = tempnam (tmpdir, ".rwtmp");
 
     if (!fname)
         return -1;