um: Use race-free temporary file creation

Open the memory mapped file with the O_TMPFILE flag when available.

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Acked-by: Tristan Schmelcher <tschmelcher@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Mickaël Salaün 2015-12-22 22:15:10 +01:00 committed by Richard Weinberger
parent 571d2f0c34
commit 3e46b25376

View File

@ -106,6 +106,17 @@ static int __init make_tempfile(const char *template)
}
}
#ifdef O_TMPFILE
fd = open(tempdir, O_CLOEXEC | O_RDWR | O_EXCL | O_TMPFILE, 0700);
/*
* If the running system does not support O_TMPFILE flag then retry
* without it.
*/
if (fd != -1 || (errno != EINVAL && errno != EISDIR &&
errno != EOPNOTSUPP))
return fd;
#endif
tempname = malloc(strlen(tempdir) + strlen(template) + 1);
if (tempname == NULL)
return -1;