* unix/tclUnixPipe.c (DefaultTempDir): [Bug 2933003]: Allow overriding

	of the back-stop default temporary file location at compile time by
	setting the TCL_TEMPORARY_FILE_DIRECTORY #def to a string containing
	the directory name (defaults to "/tmp" as that is the most common
	default).

2 files changed, 59 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index ee34c44..9a4d5340 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2012-11-14  Donal K. Fellows  <dkf@users.sf.net>
+
+	* unix/tclUnixPipe.c (DefaultTempDir): [Bug 2933003]: Allow overriding
+	of the back-stop default temporary file location at compile time by
+	setting the TCL_TEMPORARY_FILE_DIRECTORY #def to a string containing
+	the directory name (defaults to "/tmp" as that is the most common
+	default).
+
 2012-11-13  Joe Mistachkin  <joe@mistachkin.com>
 
 	* win/tclWinInit.c: also search for the library directory (init.tcl,
diff --git a/unix/tclUnixPipe.c b/unix/tclUnixPipe.c
index 105f032..d0a5e53 100644
--- a/unix/tclUnixPipe.c
+++ b/unix/tclUnixPipe.c
@@ -18,6 +18,16 @@
 #endif
 
 /*
+ * Fallback temporary file location the temporary file generation code. Can be
+ * overridden at compile time for when it is known that temp files can't be
+ * written to /tmp (hello, iOS!).
+ */
+
+#ifndef TCL_TEMPORARY_FILE_DIRECTORY
+#define TCL_TEMPORARY_FILE_DIRECTORY	"/tmp"
+#endif
+
+/*
  * The following macros convert between TclFile's and fd's. The conversion
  * simple involves shifting fd's up by one to ensure that no valid fd is ever
  * the same as NULL.
@@ -48,6 +58,7 @@ typedef struct PipeState {
  * Declarations for local functions defined in this file:
  */
 
+static const char *	DefaultTempDir(void);
 static int		PipeBlockModeProc(ClientData instanceData, int mode);
 static int		PipeCloseProc(ClientData instanceData,
 			    Tcl_Interp *interp);
@@ -198,7 +209,7 @@ TclpCreateTempFile(
      * We should also check against making more then TMP_MAX of these.
      */
 
-    strcpy(fileName, P_tmpdir);				/* INTL: Native. */
+    strcpy(fileName, DefaultTempDir());			/* INTL: Native. */
     if (fileName[strlen(fileName) - 1] != '/') {
 	strcat(fileName, "/");				/* INTL: Native. */
     }
@@ -250,7 +261,7 @@ TclpTempFileName(void)
      * We should also check against making more then TMP_MAX of these.
      */
 
-    strcpy(fileName, P_tmpdir);		/* INTL: Native. */
+    strcpy(fileName, DefaultTempDir());	/* INTL: Native. */
     if (fileName[strlen(fileName) - 1] != '/') {
 	strcat(fileName, "/");		/* INTL: Native. */
     }
@@ -270,6 +281,44 @@ TclpTempFileName(void)
 /*
  *----------------------------------------------------------------------
  *
+ * DefaultTempDir --
+ *
+ *	Helper that does *part* of what tempnam() does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static const char *
+DefaultTempDir(void)
+{
+    const char *dir;
+    struct stat buf;
+
+    dir = getenv("TMPDIR");
+    if (dir && dir[0] && stat(dir, &buf) == 0 && S_ISDIR(buf.st_mode)
+	    && access(dir, W_OK)) {
+	return dir;
+    }
+
+#ifdef P_tmpdir
+    dir = P_tmpdir;
+    if (stat(dir, &buf) == 0 && S_ISDIR(buf.st_mode) && access(dir, W_OK)) {
+	return dir;
+    }
+#endif
+
+    /*
+     * Assume that the default location ("/tmp" if not overridden) is always
+     * an existing writable directory; we've no recovery mechanism if it
+     * isn't.
+     */
+
+    return TCL_TEMPORARY_FILE_DIRECTORY;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * TclpCreatePipe --
  *
  *	Creates a pipe - simply calls the pipe() function.