cancellation support for a large amount of the required syscalls

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/common/writev.c b/libc/sysdeps/linux/common/writev.c
index 99de7e43d..bd0e4077d 100644
--- a/libc/sysdeps/linux/common/writev.c
+++ b/libc/sysdeps/linux/common/writev.c
@@ -10,5 +10,41 @@
 #include <sys/syscall.h>
 #include <sys/uio.h>
 
+#ifdef __UCLIBC_HAS_THREADS_NATIVE__
+#include <errno.h>
+#include <sysdep-cancel.h>
+
+/* We should deal with kernel which have a smaller UIO_FASTIOV as well
+   as a very big count.  */
+static ssize_t __writev (int fd, const struct iovec *vector, int count)
+{
+  ssize_t bytes_written;
+
+  bytes_written = INLINE_SYSCALL (writev, 3, fd, vector, count);
+
+  if (bytes_written >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
+    return bytes_written;
+
+  /* glibc tries again, but we do not. */
+  /* return __atomic_writev_replacement (fd, vector, count); */
+
+  return -1;
+}
+
+ssize_t writev (int fd, const struct iovec *vector, int count)
+{
+  if (SINGLE_THREAD_P)
+    return __writev (fd, vector, count);
+
+  int oldtype = LIBC_CANCEL_ASYNC ();
+
+  ssize_t result = __writev (fd, vector, count);
+
+  LIBC_CANCEL_RESET (oldtype);
+
+  return result;
+}
+#else
 _syscall3(ssize_t, writev, int, filedes, const struct iovec *, vector,
 		  int, count)
+#endif