qemu-file: pass errno from qemu_fflush via f->last_error

[qemu.git] / savevm.c

diff --git a/savevm.c b/savevm.c
index 4eb29b2ae23215a76bd25e2cfcb861706923753e..a6811779642ed9fc1a35224028a592180b217b16 100644 (file)
--- a/savevm.c
+++ b/savevm.c
@@ -140,6 +140,34 @@ typedef struct QEMUFileSocket
     QEMUFile *file;
 } QEMUFileSocket;
 
+typedef struct {
+    Coroutine *co;
+    int fd;
+} FDYieldUntilData;
+
+static void fd_coroutine_enter(void *opaque)
+{
+    FDYieldUntilData *data = opaque;
+    qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
+    qemu_coroutine_enter(data->co, NULL);
+}
+
+/**
+ * Yield until a file descriptor becomes readable
+ *
+ * Note that this function clobbers the handlers for the file descriptor.
+ */
+static void coroutine_fn yield_until_fd_readable(int fd)
+{
+    FDYieldUntilData data;
+
+    assert(qemu_in_coroutine());
+    data.co = qemu_coroutine_self();
+    data.fd = fd;
+    qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
+    qemu_coroutine_yield();
+}
+
 static int socket_get_fd(void *opaque)
 {
     QEMUFileSocket *s = opaque;
@@ -158,8 +186,7 @@ static int socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
             break;
         }
         if (socket_error() == EAGAIN) {
-            assert(qemu_in_coroutine());
-            qemu_coroutine_yield();
+            yield_until_fd_readable(s->fd);
         } else if (socket_error() != EINTR) {
             break;
         }
@@ -205,8 +232,7 @@ static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
             break;
         }
         if (errno == EAGAIN) {
-            assert(qemu_in_coroutine());
-            qemu_coroutine_yield();
+            yield_until_fd_readable(fileno(fp));
         } else if (errno != EINTR) {
             break;
         }
@@ -427,13 +453,13 @@ static void qemu_file_set_error(QEMUFile *f, int ret)
 /** Flushes QEMUFile buffer
  *
  */
-static int qemu_fflush(QEMUFile *f)
+static void qemu_fflush(QEMUFile *f)
 {
     int ret = 0;
 
-    if (!f->ops->put_buffer)
-        return 0;
-
+    if (!f->ops->put_buffer) {
+        return;
+    }
     if (f->is_write && f->buf_index > 0) {
         ret = f->ops->put_buffer(f->opaque, f->buf, f->buf_offset, f->buf_index);
         if (ret >= 0) {
@@ -441,7 +467,9 @@ static int qemu_fflush(QEMUFile *f)
         }
         f->buf_index = 0;
     }
-    return ret;
+    if (ret < 0) {
+        qemu_file_set_error(f, ret);
+    }
 }
 
 static void qemu_fill_buffer(QEMUFile *f)
@@ -492,7 +520,8 @@ int qemu_get_fd(QEMUFile *f)
 int qemu_fclose(QEMUFile *f)
 {
     int ret;
-    ret = qemu_fflush(f);
+    qemu_fflush(f);
+    ret = qemu_file_get_error(f);
 
     if (f->ops->close) {
         int ret2 = f->ops->close(f->opaque);
@@ -534,9 +563,8 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
         buf += l;
         size -= l;
         if (f->buf_index >= IO_BUF_SIZE) {
-            int ret = qemu_fflush(f);
-            if (ret < 0) {
-                qemu_file_set_error(f, ret);
+            qemu_fflush(f);
+            if (qemu_file_get_error(f)) {
                 break;
             }
         }
@@ -558,10 +586,7 @@ void qemu_put_byte(QEMUFile *f, int v)
     f->buf[f->buf_index++] = v;
     f->is_write = 1;
     if (f->buf_index >= IO_BUF_SIZE) {
-        int ret = qemu_fflush(f);
-        if (ret < 0) {
-            qemu_file_set_error(f, ret);
-        }
+        qemu_fflush(f);
     }
 }
 
@@ -647,9 +672,14 @@ int qemu_get_byte(QEMUFile *f)
     return result;
 }
 
-static int64_t qemu_ftell(QEMUFile *f)
+int64_t qemu_ftell(QEMUFile *f)
 {
-    return f->buf_offset - f->buf_size + f->buf_index;
+    /* buf_offset excludes buffer for writing but includes it for reading */
+    if (f->is_write) {
+        return f->buf_offset + f->buf_index;
+    } else {
+        return f->buf_offset - f->buf_size + f->buf_index;
+    }
 }
 
 int qemu_file_rate_limit(QEMUFile *f)
@@ -1590,17 +1620,11 @@ int qemu_savevm_state_begin(QEMUFile *f,
 
         ret = se->ops->save_live_setup(f, se->opaque);
         if (ret < 0) {
-            qemu_savevm_state_cancel();
             return ret;
         }
     }
     ret = qemu_file_get_error(f);
-    if (ret != 0) {
-        qemu_savevm_state_cancel();
-    }
-
     return ret;
-
 }
 
 /*
@@ -1646,9 +1670,6 @@ int qemu_savevm_state_iterate(QEMUFile *f)
         return ret;
     }
     ret = qemu_file_get_error(f);
-    if (ret != 0) {
-        qemu_savevm_state_cancel();
-    }
     return ret;
 }
 
@@ -1747,8 +1768,7 @@ static int qemu_savevm_state(QEMUFile *f)
     };
 
     if (qemu_savevm_state_blocked(NULL)) {
-        ret = -EINVAL;
-        goto out;
+        return -EINVAL;
     }
 
     ret = qemu_savevm_state_begin(f, &params);
@@ -1767,6 +1787,9 @@ out:
     if (ret == 0) {
         ret = qemu_file_get_error(f);
     }
+    if (ret != 0) {
+        qemu_savevm_state_cancel();
+    }
 
     return ret;
 }