* unix/tclUnixFCmd.c (TclUnixOpenTemporaryFile): [Bug 2933003]: Factor

	out all the code to do temporary file creation so that it is possible
	to make it correct in one place. 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, 56 insertions, 41 deletions

diff --git a/unix/tclUnixFCmd.c b/unix/tclUnixFCmd.c
index d3cc6bf..559992f 100644
--- a/unix/tclUnixFCmd.c
+++ b/unix/tclUnixFCmd.c
@@ -62,6 +62,16 @@
 #define DOTREE_F	3	/* regular file */
 
 /*
+ * 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
+
+/*
  * Callbacks for file attributes code.
  */
 
@@ -2093,7 +2103,7 @@ TclpObjNormalizePath(
 /*
  *----------------------------------------------------------------------
  *
- * TclpOpenTemporaryFile --
+ * TclpOpenTemporaryFile, TclUnixOpenTemporaryFile --
  *
  *	Creates a temporary file, possibly based on the supplied bits and
  *	pieces of template supplied in the first three arguments. If the
@@ -2103,7 +2113,12 @@ TclpObjNormalizePath(
  *	file to go away once it is no longer needed.
  *
  * Results:
- *	A read-write Tcl Channel open on the file.
+ *	A read-write Tcl Channel open on the file for TclpOpenTemporaryFile,
+ *	or a file descriptor (or -1 on failure) for TclUnixOpenTemporaryFile.
+ *
+ * Side effects:
+ *	Accesses the filesystem. Will set the contents of the Tcl_Obj fourth
+ *	argument (if that is non-NULL).
  *
  *----------------------------------------------------------------------
  */
@@ -2115,11 +2130,30 @@ TclpOpenTemporaryFile(
     Tcl_Obj *extensionObj,
     Tcl_Obj *resultingNameObj)
 {
-    Tcl_Channel chan;
+    int fd = TclUnixOpenTemporaryFile(dirObj, basenameObj, extensionObj,
+	    resultingNameObj);
+
+    if (fd == -1) {
+	return NULL;
+    }
+    return Tcl_MakeFileChannel(INT2PTR(fd), TCL_READABLE|TCL_WRITABLE);
+}
+
+int
+TclUnixOpenTemporaryFile(
+    Tcl_Obj *dirObj,
+    Tcl_Obj *basenameObj,
+    Tcl_Obj *extensionObj,
+    Tcl_Obj *resultingNameObj)
+{
     Tcl_DString template, tmp;
     const char *string;
     int len, fd;
 
+    /*
+     * We should also check against making more then TMP_MAX of these.
+     */
+
     if (dirObj) {
 	string = Tcl_GetStringFromObj(dirObj, &len);
 	Tcl_UtfToExternalDString(NULL, string, len, &template);
@@ -2155,9 +2189,10 @@ TclpOpenTemporaryFile(
     }
 
     if (fd == -1) {
-	return NULL;
+	Tcl_DStringFree(&template);
+	return -1;
     }
-    chan = Tcl_MakeFileChannel(INT2PTR(fd), TCL_READABLE|TCL_WRITABLE);
+
     if (resultingNameObj) {
 	Tcl_ExternalToUtfDString(NULL, Tcl_DStringValue(&template),
 		Tcl_DStringLength(&template), &tmp);
@@ -2176,7 +2211,7 @@ TclpOpenTemporaryFile(
     }
     Tcl_DStringFree(&template);
 
-    return chan;
+    return fd;
 }
 
 /*
@@ -2203,11 +2238,12 @@ DefaultTempDir(void)
 #endif
 
     /*
-     * Assume that "/tmp" is always an existing writable directory; we've no
-     * recovery mechanism if it isn't.
+     * 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 "/tmp";
+    return TCL_TEMPORARY_FILE_DIRECTORY;
 }
 
 #if defined(HAVE_CHFLAGS) && defined(UF_IMMUTABLE)
diff --git a/unix/tclUnixPipe.c b/unix/tclUnixPipe.c
index 654c9d8..9c21b28 100644
--- a/unix/tclUnixPipe.c
+++ b/unix/tclUnixPipe.c
@@ -188,28 +188,16 @@ TclFile
 TclpCreateTempFile(
     const char *contents)	/* String to write into temp file, or NULL. */
 {
-    char fileName[L_tmpnam + 9];
-    const char *native;
-    Tcl_DString dstring;
-    int fd;
+    int fd = TclUnixOpenTemporaryFile(NULL, NULL, NULL, NULL);
 
-    /*
-     * We should also check against making more then TMP_MAX of these.
-     */
-
-    strcpy(fileName, P_tmpdir);				/* INTL: Native. */
-    if (fileName[strlen(fileName) - 1] != '/') {
-	strcat(fileName, "/");				/* INTL: Native. */
-    }
-    strcat(fileName, "tclXXXXXX");
-    fd = mkstemp(fileName);				/* INTL: Native. */
     if (fd == -1) {
 	return NULL;
     }
     fcntl(fd, F_SETFD, FD_CLOEXEC);
-    unlink(fileName);					/* INTL: Native. */
-
     if (contents != NULL) {
+	Tcl_DString dstring;
+	char *native;
+
 	native = Tcl_UtfToExternalDString(NULL, contents, -1, &dstring);
 	if (write(fd, native, Tcl_DStringLength(&dstring)) == -1) {
 	    close(fd);
@@ -241,29 +229,20 @@ TclpCreateTempFile(
 Tcl_Obj *
 TclpTempFileName(void)
 {
-    char fileName[L_tmpnam + 9];
-    Tcl_Obj *result = NULL;
+    Tcl_Obj *nameObj = Tcl_NewObj();
     int fd;
 
-    /*
-     * We should also check against making more then TMP_MAX of these.
-     */
-
-    strcpy(fileName, P_tmpdir);		/* INTL: Native. */
-    if (fileName[strlen(fileName) - 1] != '/') {
-	strcat(fileName, "/");		/* INTL: Native. */
-    }
-    strcat(fileName, "tclXXXXXX");
-    fd = mkstemp(fileName);		/* INTL: Native. */
+    Tcl_IncrRefCount(nameObj);
+    fd = TclUnixOpenTemporaryFile(NULL, NULL, NULL, nameObj);
     if (fd == -1) {
+	Tcl_DecrRefCount(nameObj);
 	return NULL;
     }
-    fcntl(fd, F_SETFD, FD_CLOEXEC);
-    unlink(fileName);			/* INTL: Native. */
 
-    result = TclpNativeToNormalized(fileName);
+    fcntl(fd, F_SETFD, FD_CLOEXEC);
+    TclpObjDeleteFile(nameObj);
     close(fd);
-    return result;
+    return nameObj;
 }
 
 /*