Read a batch of iovec's.
In the common case of short reads, finish individual iov's with read_exact.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
Users will follow, next month probably.
tools/libs/ctrl/xc_private.c | 54 +++++++++++++++++++++++++++++++++++-
tools/libs/ctrl/xc_private.h | 1 +
2 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/tools/libs/ctrl/xc_private.c b/tools/libs/ctrl/xc_private.c
index d94f846686..a86ed213a5 100644
--- a/tools/libs/ctrl/xc_private.c
+++ b/tools/libs/ctrl/xc_private.c
@@ -659,8 +659,22 @@ int write_exact(int fd, const void *data, size_t size)
#if defined(__MINIOS__)
/*
- * MiniOS's libc doesn't know about writev(). Implement it as multiple write()s.
+ * MiniOS's libc doesn't know about readv/writev(). Implement it as multiple write()s.
*/
+int readv_exact(int fd, const struct iovec *iov, int iovcnt)
+{
+ int rc, i;
+
+ for ( i = 0; i < iovcnt; ++i )
+ {
+ rc = read_exact(fd, iov[i].iov_base, iov[i].iov_len);
+ if ( rc )
+ return rc;
+ }
+
+ return 0;
+}
+
int writev_exact(int fd, const struct iovec *iov, int iovcnt)
{
int rc, i;
@@ -675,6 +689,44 @@ int writev_exact(int fd, const struct iovec *iov, int iovcnt)
return 0;
}
#else
+int readv_exact(int fd, const struct iovec *iov, int iovcnt)
+{
+ int rc = 0, idx = 0;
+ ssize_t len;
+
+ while ( idx < iovcnt )
+ {
+ len = readv(fd, &iov[idx], min(iovcnt - idx, IOV_MAX));
+ if ( len == -1 && errno == EINTR )
+ continue;
+ if ( len <= 0 )
+ {
+ rc = -1;
+ goto out;
+ }
+ while ( len > 0 && idx < iovcnt )
+ {
+ if ( len >= iov[idx].iov_len )
+ {
+ len -= iov[idx].iov_len;
+ }
+ else
+ {
+ void *p = iov[idx].iov_base + len;
+ size_t l = iov[idx].iov_len - len;
+
+ rc = read_exact(fd, p, l);
+ if ( rc )
+ goto out;
+ len = 0;
+ }
+ idx++;
+ }
+ }
+out:
+ return rc;
+}
+
int writev_exact(int fd, const struct iovec *iov, int iovcnt)
{
struct iovec *local_iov = NULL;
diff --git a/tools/libs/ctrl/xc_private.h b/tools/libs/ctrl/xc_private.h
index f0b5f83ac8..5d2c7274fb 100644
--- a/tools/libs/ctrl/xc_private.h
+++ b/tools/libs/ctrl/xc_private.h
@@ -441,6 +441,7 @@ int xc_flush_mmu_updates(xc_interface *xch, struct xc_mmu *mmu);
/* Return 0 on success; -1 on error setting errno. */
int read_exact(int fd, void *data, size_t size); /* EOF => -1, errno=0 */
+int readv_exact(int fd, const struct iovec *iov, int iovcnt);
int write_exact(int fd, const void *data, size_t size);
int writev_exact(int fd, const struct iovec *iov, int iovcnt);