diff mbox series

[v14,RESEND,09/21] multi-process: add qio channel read function

Message ID 2db8d84f89fc7263a886eab482040507b1fb6a5d.1608263018.git.elena.ufimtseva@oracle.com (mailing list archive)
State New, archived
Headers show
Series Initial support for multi-process Qemu | expand

Commit Message

Elena Ufimtseva Dec. 18, 2020, 5:40 a.m. UTC 
From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Adds qio_channel_readv_full_all() to read both data and FDs.
Refactors existing code to use this function.

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
---
 include/io/channel.h | 25 ++++++++++++++++
 io/channel.c         | 71 ++++++++++++++++++++++++++++----------------
 2 files changed, 71 insertions(+), 25 deletions(-)

Comments

Stefan Hajnoczi Dec. 22, 2020, 10:29 a.m. UTC | #1 
On Thu, Dec 17, 2020 at 09:40:39PM -0800, elena.ufimtseva@oracle.com wrote:
> +int qio_channel_readv_full_all(QIOChannel *ioc,
> +                                const struct iovec *iov,
> +                                size_t niov,
> +                                int **fds, size_t *nfds,
> +                                Error **errp)
>  {
>      int ret = -1;
>      struct iovec *local_iov = g_new(struct iovec, niov);
>      struct iovec *local_iov_head = local_iov;
>      unsigned int nlocal_iov = niov;
> +    int **local_fds = fds;
> +    size_t *local_nfds = nfds;
>      bool partial = false;
>  
>      nlocal_iov = iov_copy(local_iov, nlocal_iov,
> @@ -104,7 +140,8 @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
>  
>      while (nlocal_iov > 0) {
>          ssize_t len;
> -        len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
> +        len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds,
> +                                     local_nfds, errp);
>          if (len == QIO_CHANNEL_ERR_BLOCK) {
>              if (qemu_in_coroutine()) {
>                  qio_channel_yield(ioc, G_IO_IN);
> @@ -112,20 +149,21 @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
>                  qio_channel_wait(ioc, G_IO_IN);
>              }
>              continue;
> -        } else if (len < 0) {
> -            goto cleanup;
> -        } else if (len == 0) {
> -            if (partial) {
> -                error_setg(errp,
> -                           "Unexpected end-of-file before all bytes were read");
> +        }
> +        if (len <= 0) {
> +            if (partial && (len == 0)) {
> +                ret = -ECANCELED;

Do callers expect fds to be non-NULL when an error is returned? This
could lead to file descriptor and memory leaks.
diff mbox series

Patch

diff --git a/include/io/channel.h b/include/io/channel.h
index 2378567d4b..429ece9a05 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -774,6 +774,31 @@  void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
                                     IOHandler *io_write,
                                     void *opaque);
 
+/**
+ * qio_channel_readv_full_all:
+ * @ioc: the channel object
+ * @iov: the array of memory regions to read data to
+ * @niov: the length of the @iov array
+ * @fds: an array of file handles to read
+ * @nfds: number of file handles in @fds
+ * @errp: pointer to a NULL-initialized error object
+ *
+ *
+ * Behaves like qio_channel_readv_full but will attempt
+ * to read all data specified (file handles and memory regions).
+ * The function will wait for all requested data
+ * to be read, yielding from the current coroutine
+ * if required.
+ *
+ * Returns: 0 if all bytes were read, or -1 on error
+ */
+
+int qio_channel_readv_full_all(QIOChannel *ioc,
+                                const struct iovec *iov,
+                                size_t niov,
+                                int **fds, size_t *nfds,
+                                Error **errp);
+
 /**
  * qio_channel_writev_full_all:
  * @ioc: the channel object
diff --git a/io/channel.c b/io/channel.c
index bde1f6d0f4..0b084e343f 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -91,11 +91,47 @@  int qio_channel_readv_all_eof(QIOChannel *ioc,
                               const struct iovec *iov,
                               size_t niov,
                               Error **errp)
+{
+    int ret = qio_channel_readv_full_all(ioc, iov, niov, NULL, NULL, errp);
+
+    if (ret == -ECANCELED) {
+        error_prepend(errp,
+                      "Unexpected end-of-file before all bytes were read: ");
+        ret = -1;
+    }
+
+    return ret;
+}
+
+int qio_channel_readv_all(QIOChannel *ioc,
+                          const struct iovec *iov,
+                          size_t niov,
+                          Error **errp)
+{
+    int ret = qio_channel_readv_all_eof(ioc, iov, niov, errp);
+
+    if (ret == 0) {
+        ret = -1;
+        error_setg(errp,
+                   "Unexpected end-of-file before all bytes were read");
+    } else if (ret == 1) {
+        ret = 0;
+    }
+    return ret;
+}
+
+int qio_channel_readv_full_all(QIOChannel *ioc,
+                                const struct iovec *iov,
+                                size_t niov,
+                                int **fds, size_t *nfds,
+                                Error **errp)
 {
     int ret = -1;
     struct iovec *local_iov = g_new(struct iovec, niov);
     struct iovec *local_iov_head = local_iov;
     unsigned int nlocal_iov = niov;
+    int **local_fds = fds;
+    size_t *local_nfds = nfds;
     bool partial = false;
 
     nlocal_iov = iov_copy(local_iov, nlocal_iov,
@@ -104,7 +140,8 @@  int qio_channel_readv_all_eof(QIOChannel *ioc,
 
     while (nlocal_iov > 0) {
         ssize_t len;
-        len = qio_channel_readv(ioc, local_iov, nlocal_iov, errp);
+        len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds,
+                                     local_nfds, errp);
         if (len == QIO_CHANNEL_ERR_BLOCK) {
             if (qemu_in_coroutine()) {
                 qio_channel_yield(ioc, G_IO_IN);
@@ -112,20 +149,21 @@  int qio_channel_readv_all_eof(QIOChannel *ioc,
                 qio_channel_wait(ioc, G_IO_IN);
             }
             continue;
-        } else if (len < 0) {
-            goto cleanup;
-        } else if (len == 0) {
-            if (partial) {
-                error_setg(errp,
-                           "Unexpected end-of-file before all bytes were read");
+        }
+        if (len <= 0) {
+            if (partial && (len == 0)) {
+                ret = -ECANCELED;
             } else {
-                ret = 0;
+                ret = len;
             }
             goto cleanup;
         }
 
         partial = true;
         iov_discard_front(&local_iov, &nlocal_iov, len);
+
+        local_fds = NULL;
+        local_nfds = 0;
     }
 
     ret = 1;
@@ -135,23 +173,6 @@  int qio_channel_readv_all_eof(QIOChannel *ioc,
     return ret;
 }
 
-int qio_channel_readv_all(QIOChannel *ioc,
-                          const struct iovec *iov,
-                          size_t niov,
-                          Error **errp)
-{
-    int ret = qio_channel_readv_all_eof(ioc, iov, niov, errp);
-
-    if (ret == 0) {
-        ret = -1;
-        error_setg(errp,
-                   "Unexpected end-of-file before all bytes were read");
-    } else if (ret == 1) {
-        ret = 0;
-    }
-    return ret;
-}
-
 int qio_channel_writev_all(QIOChannel *ioc,
                            const struct iovec *iov,
                            size_t niov,