Re: patch: fix usage of mkstemp() in rdistd

[Todd C. Miller]

On Mon, 28 Mar 2016 10:19:12 +0200, Paul Kelly wrote:

> On 03/28/16 04:05, Todd C. Miller wrote:
>  > I think it's best to just check the parent directories first and
>  > then create the temp name.
>  >
>  >   - todd
> 
> This works for me and avoids my hacking around with new. I added a few 
> extra destination directories and it seems to hold up OK. Thanks!

Another option is to just open the file directly after creating the
intermediate directories.  This is effectively what used to happen
before mkstemp(3) was changed to return an error when no Xs are
found in the format.  That way you still save a stat call when there
directories already exist (the common case).

 - todd

Index: server.c
===================================================================
RCS file: /cvs/src/usr.bin/rdistd/server.c,v
retrieving revision 1.40
diff -u -p -u -r1.40 server.c
--- server.c    22 Dec 2015 08:48:39 -0000      1.40
+++ server.c    28 Mar 2016 12:35:53 -0000
@@ -752,7 +752,7 @@ recvfile(char *new, opt_t opts, int mode
         */
        if ((f = mkstemp(new)) < 0) {
                if (errno != ENOENT || chkparent(new, opts) < 0 ||
-                   (f = mkstemp(new)) < 0) {
+                   (f = open(new, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR)) < 
0) {
                        error("%s: create failed: %s", new, SYSERR);
                        return;
                }
@@ -1163,7 +1163,7 @@ recvlink(char *new, opt_t opts, int mode
         */
        if (mktemp(new) == NULL || symlink(dbuf, new) < 0) {
                if (errno != ENOENT || chkparent(new, opts) < 0 ||
-                   mktemp(new) == NULL || symlink(dbuf, new) < 0) {
+                   symlink(dbuf, new) < 0) {
                        error("%s -> %s: symlink failed: %s", new, dbuf,
                            SYSERR);
                        return;