x86 __vdso_gettc: add O_CLOEXEC flag to open

[kib]

Summary

of the /dev/hpet and /dev/hv_tsc devices, to not leak internal libc filedescriptors on exec.

[markj]

BTW, there are a couple of _opens() in the locale code which should use O_CLOEXEC as well:

diff --git a/lib/libc/locale/collate.c b/lib/libc/locale/collate.c
index c992d2299ab7..7afb2043e6a4 100644
--- a/lib/libc/locale/collate.c
+++ b/lib/libc/locale/collate.c
@@ -131,7 +131,7 @@ __collate_load_tables_l(const char *encoding, struct xlocale_collate *table)
        if (asprintf(&buf, "%s/%s/LC_COLLATE", _PathLocale, encoding) == -1)
                return (_LDP_ERROR);
 
-       if ((fd = _open(buf, O_RDONLY)) < 0) {
+       if ((fd = _open(buf, O_RDONLY | O_CLOEXEC)) < 0) {
                free(buf);
                return (_LDP_ERROR);
        }
diff --git a/lib/libc/locale/rune.c b/lib/libc/locale/rune.c
index b7334636f654..ce2095763eba 100644
--- a/lib/libc/locale/rune.c
+++ b/lib/libc/locale/rune.c
@@ -74,7 +74,7 @@ _Read_RuneMagi(const char *fname)
        int runetype_ext_len = 0;
        int fd;
 
-       if ((fd = _open(fname, O_RDONLY)) < 0) {
+       if ((fd = _open(fname, O_RDONLY | O_CLOEXEC)) < 0) {
                errno = EINVAL;
                return (NULL);
        }

[kib]

In D31344#706245, @markj wrote:

BTW, there are a couple of _opens() in the locale code which should use O_CLOEXEC as well:

This looks fine, but should be a separate change (yours).