From: Daniel Shahaf <danielsh@apache.org>
To: zsh-workers@zsh.org
Subject: [PATCH 1/3] Fix the mktemp() warning, in debug builds only.
Date: Tue, 17 Dec 2019 07:44:26 +0000 [thread overview]
Message-ID: <20191217074428.3699-1-danielsh@apache.org> (raw)
On Linux, linking to mktemp() generates the following warning:
.
utils.o: In function `gettempname':
./Src/utils.c:2229: warning: the use of `mktemp' is dangerous, better use `mkstemp' or `mkdtemp'
The warning cannot be disabled.
Work around that by using mkstemp() instead, and massage its output so
it behaves like mktemp(). See the new comment for further details.
---
The purpose of this patch is to eliminate the spurious warning from the
edit-compile-test cycle.
Cheers,
Daniel
Src/utils.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/Src/utils.c b/Src/utils.c
index 1d916e71f..086c0dfcb 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -2201,6 +2201,31 @@ gettempname(const char *prefix, int use_heap)
#ifdef HAVE__MKTEMP
/* Zsh uses mktemp() safely, so silence the warnings */
ret = (char *) _mktemp(ret);
+#elif HAVE_MKSTEMP && defined(DEBUG)
+ {
+ /* zsh uses mktemp() safely (all callers use O_EXCL, and one of them
+ * uses mkfifo()/mknod(), as opposed to open()), but some compilers
+ * warn about this anyway and give no way to disable the warning. To
+ * appease them, use mkstemp() and then close the fd and unlink the
+ * filename, to match callers' expectations.
+ *
+ * But do this in debug builds only, because we don't want to suffer
+ * x3 the disk access (touch, unlink, touch again) in production.
+ */
+ int fd;
+ errno = 0;
+ fd = mkstemp(ret);
+ if (fd < 0)
+ zwarn("can't get a temporary filename: %e", errno);
+ else {
+ close(fd);
+ ret = ztrdup(ret);
+
+ errno = 0;
+ if (unlink(ret) < 0)
+ zwarn("unlinking a temporary filename failed: %e", errno);
+ }
+ }
#else
ret = (char *) mktemp(ret);
#endif
next reply other threads:[~2019-12-17 7:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 7:44 Daniel Shahaf [this message]
2019-12-17 7:44 ` [PATCH 2/3] Make 'make -s' print nothing when it does nothing Daniel Shahaf
2019-12-17 7:44 ` [PATCH 3/3] internal: Document forklevel, locallevel, and exit_pending Daniel Shahaf
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