- djm@cvs.openbsd.org 2006/04/16 00:52:55

     [atomicio.c atomicio.h]
     introduce atomiciov() function that wraps readv/writev to retry
     interrupted transfers like atomicio() does for read/write;
     feedback deraadt@ dtucker@ stevesk@ ok deraadt@

1 files changed, 54 insertions, 1 deletions

diff --git a/atomicio.c b/atomicio.c
index 996beff2f..de5363aa3 100644
--- a/atomicio.c
+++ b/atomicio.c
@@ -1,5 +1,6 @@
-/* $OpenBSD: atomicio.c,v 1.17 2006/04/01 05:51:34 djm Exp $ */
+/* $OpenBSD: atomicio.c,v 1.18 2006/04/16 00:52:55 djm Exp $ */
 /*
+ * Copyright (c) 2006 Damien Miller. All rights reserved.
  * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
  * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
  * All rights reserved.
@@ -59,3 +60,55 @@ atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
         }
         return (pos);
 }
+
+/*
+ * ensure all of data on socket comes through. f==readv || f==writev
+ */
+size_t
+atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
+    const struct iovec *_iov, int iovcnt)
+{
+        size_t pos = 0, rem;
+        ssize_t res;
+        struct iovec iov_array[IOV_MAX], *iov = iov_array;
+
+        if (iovcnt > IOV_MAX) {
+                errno = EINVAL;
+                return 0;
+        }
+        /* Make a copy of the iov array because we may modify it below */
+        memcpy(iov, _iov, iovcnt * sizeof(*_iov));
+
+        for (; iovcnt > 0 && iov[0].iov_len > 0;) {
+                res = (f) (fd, iov, iovcnt);
+                switch (res) {
+                case -1:
+                        if (errno == EINTR || errno == EAGAIN)
+                                continue;
+                        return 0;
+                case 0:
+                        errno = EPIPE;
+                        return pos;
+                default:
+                        rem = (size_t)res;
+                        pos += rem;
+                        /* skip completed iov entries */
+                        while (iovcnt > 0 && rem >= iov[0].iov_len) {
+                                rem -= iov[0].iov_len;
+                                iov++;
+                                iovcnt--;
+                        }
+                        /* This shouldn't happen... */
+                        if (rem > iov[0].iov_len || (rem > 0 && iovcnt <= 0)) {
+                                errno = EFAULT;
+                                return 0;
+                        }
+                        if (iovcnt == 0)
+                                break;
+                        /* update pointer in partially complete iov */
+                        iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
+                        iov[0].iov_len -= rem;
+                }
+        }
+        return pos;
+}