fix signalfd not to ignore flags

also include fallback code for broken kernels that don't support the
flags. as usual, the fallback has a race condition that can leak file
descriptors.

diff --git a/src/linux/signalfd.c b/src/linux/signalfd.c
index 94de36278bea1f6385325a2812ea657fc3a158d9..da6bcedb3f905ce00659f1b0e68855669541bce8 100644 (file)
--- a/src/linux/signalfd.c
+++ b/src/linux/signalfd.c
@@ -1,8 +1,19 @@
 #include <sys/signalfd.h>
 #include <signal.h>
+#include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 int signalfd(int fd, const sigset_t *sigs, int flags)
 {
-       return syscall(SYS_signalfd, fd, sigs, _NSIG/8);
+       int ret = __syscall(SYS_signalfd4, fd, sigs, _NSIG/8, flags);
+       if (ret != -ENOSYS) return __syscall_ret(ret);
+       ret = __syscall(SYS_signalfd, fd, sigs, _NSIG/8);
+       if (ret >= 0) {
+               if (flags & SFD_CLOEXEC)
+                       __syscall(SYS_fcntl, ret, F_SETFD, FD_CLOEXEC);
+               if (flags & SFD_NONBLOCK)
+                       __syscall(SYS_fcntl, ret, F_SETFL, O_NONBLOCK);
+       }
+       return __syscall_ret(ret);
 }