We assert that nullfd if not std{in,out,err} since that would result
in closing one of the just dup2'd fds. For this to happen
std{in,out,err} would have needed to be closed, at which point all
sorts of other things could go wrong.CID: 1130519 It was previously hypothesised[0] that fixing 1130516 would solve this too, but that appears to not have been the case. Compile tested only. [0] http://lists.xenproject.org/archives/html/xen-devel/2013-11/msg02931.html Signed-off-by: Ian Campbell <ian.campb...@citrix.com> Cc: andrew.coop...@citrix.com --- v2: Assert logfile and nullfd are not stdio fds --- tools/libxl/xl_cmdimpl.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c index 9958d8a..a377de1 100644 --- a/tools/libxl/xl_cmdimpl.c +++ b/tools/libxl/xl_cmdimpl.c @@ -499,12 +499,17 @@ static int do_daemonize(char *name, const char *pidfile) CHK_SYSCALL(logfile = open(fullname, O_WRONLY|O_CREAT|O_APPEND, 0644)); free(fullname); + assert(logfile >= 3); CHK_SYSCALL(nullfd = open("/dev/null", O_RDONLY)); + assert(nullfd >= 3); + dup2(nullfd, 0); dup2(logfile, 1); dup2(logfile, 2); + close(nullfd); + CHK_SYSCALL(daemon(0, 1)); if (pidfile) { -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
