qemu-nbd: print error messages from the daemon through a pipe

[qemu.git] / savevm.c

diff --git a/savevm.c b/savevm.c
index ca9e233c9af972c73a1490e12b27e7520b6077ad..bee16c0b7b5ad88d3784b019d4eb7e62df95d933 100644 (file)
--- a/savevm.c
+++ b/savevm.c
@@ -81,6 +81,7 @@
 #include "migration.h"
 #include "qemu_socket.h"
 #include "qemu-queue.h"
+#include "qemu-timer.h"
 #include "cpus.h"
 
 #define SELF_ANNOUNCE_ROUNDS 5
@@ -173,7 +174,7 @@ struct QEMUFile {
     int buf_size; /* 0 when writing */
     uint8_t buf[IO_BUF_SIZE];
 
-    int has_error;
+    int last_error;
 };
 
 typedef struct QEMUFileStdio
@@ -425,14 +426,14 @@ QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,
     return f;
 }
 
-int qemu_file_has_error(QEMUFile *f)
+int qemu_file_get_error(QEMUFile *f)
 {
-    return f->has_error;
+    return f->last_error;
 }
 
-void qemu_file_set_error(QEMUFile *f)
+void qemu_file_set_error(QEMUFile *f, int ret)
 {
-    f->has_error = 1;
+    f->last_error = ret;
 }
 
 void qemu_fflush(QEMUFile *f)
@@ -447,7 +448,7 @@ void qemu_fflush(QEMUFile *f)
         if (len > 0)
             f->buf_offset += f->buf_index;
         else
-            f->has_error = 1;
+            f->last_error = -EINVAL;
         f->buf_index = 0;
     }
 }
@@ -475,8 +476,10 @@ static void qemu_fill_buffer(QEMUFile *f)
     if (len > 0) {
         f->buf_size += len;
         f->buf_offset += len;
+    } else if (len == 0) {
+        f->last_error = -EIO;
     } else if (len != -EAGAIN)
-        f->has_error = 1;
+        f->last_error = len;
 }
 
 int qemu_fclose(QEMUFile *f)
@@ -498,13 +501,13 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
 {
     int l;
 
-    if (!f->has_error && f->is_write == 0 && f->buf_index > 0) {
+    if (!f->last_error && f->is_write == 0 && f->buf_index > 0) {
         fprintf(stderr,
                 "Attempted to write to buffer while read buffer is not empty\n");
         abort();
     }
 
-    while (!f->has_error && size > 0) {
+    while (!f->last_error && size > 0) {
         l = IO_BUF_SIZE - f->buf_index;
         if (l > size)
             l = size;
@@ -520,7 +523,7 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
 
 void qemu_put_byte(QEMUFile *f, int v)
 {
-    if (!f->has_error && f->is_write == 0 && f->buf_index > 0) {
+    if (!f->last_error && f->is_write == 0 && f->buf_index > 0) {
         fprintf(stderr,
                 "Attempted to write to buffer while read buffer is not empty\n");
         abort();
@@ -712,6 +715,30 @@ uint64_t qemu_get_be64(QEMUFile *f)
     return v;
 }
 
+
+/* timer */
+
+void qemu_put_timer(QEMUFile *f, QEMUTimer *ts)
+{
+    uint64_t expire_time;
+
+    expire_time = qemu_timer_expire_time_ns(ts);
+    qemu_put_be64(f, expire_time);
+}
+
+void qemu_get_timer(QEMUFile *f, QEMUTimer *ts)
+{
+    uint64_t expire_time;
+
+    expire_time = qemu_get_be64(f);
+    if (expire_time != -1) {
+        qemu_mod_timer_ns(ts, expire_time);
+    } else {
+        qemu_del_timer(ts);
+    }
+}
+
+
 /* bool */
 
 static int get_bool(QEMUFile *f, void *pv, size_t size)
@@ -1504,6 +1531,7 @@ int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
                             int shared)
 {
     SaveStateEntry *se;
+    int ret;
 
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {
         if(se->set_params == NULL) {
@@ -1533,17 +1561,27 @@ int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
         qemu_put_be32(f, se->instance_id);
         qemu_put_be32(f, se->version_id);
 
-        se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
+        ret = se->save_live_state(mon, f, QEMU_VM_SECTION_START, se->opaque);
+        if (ret < 0) {
+            qemu_savevm_state_cancel(mon, f);
+            return ret;
+        }
     }
-
-    if (qemu_file_has_error(f)) {
+    ret = qemu_file_get_error(f);
+    if (ret != 0) {
         qemu_savevm_state_cancel(mon, f);
-        return -EIO;
     }
 
-    return 0;
+    return ret;
+
 }
 
+/*
+ * this funtion has three return values:
+ *   negative: there was one error, and we have -errno.
+ *   0 : We haven't finished, caller have to go again
+ *   1 : We have finished, we can go to complete phase
+ */
 int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
 {
     SaveStateEntry *se;
@@ -1558,7 +1596,7 @@ int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
         qemu_put_be32(f, se->section_id);
 
         ret = se->save_live_state(mon, f, QEMU_VM_SECTION_PART, se->opaque);
-        if (!ret) {
+        if (ret <= 0) {
             /* Do not proceed to the next vmstate before this one reported
                completion of the current stage. This serializes the migration
                and reduces the probability that a faster changing state is
@@ -1566,21 +1604,20 @@ int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
             break;
         }
     }
-
-    if (ret)
-        return 1;
-
-    if (qemu_file_has_error(f)) {
+    if (ret != 0) {
+        return ret;
+    }
+    ret = qemu_file_get_error(f);
+    if (ret != 0) {
         qemu_savevm_state_cancel(mon, f);
-        return -EIO;
     }
-
-    return 0;
+    return ret;
 }
 
 int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
 {
     SaveStateEntry *se;
+    int ret;
 
     cpu_synchronize_all_states();
 
@@ -1592,7 +1629,10 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
         qemu_put_byte(f, QEMU_VM_SECTION_END);
         qemu_put_be32(f, se->section_id);
 
-        se->save_live_state(mon, f, QEMU_VM_SECTION_END, se->opaque);
+        ret = se->save_live_state(mon, f, QEMU_VM_SECTION_END, se->opaque);
+        if (ret < 0) {
+            return ret;
+        }
     }
 
     QTAILQ_FOREACH(se, &savevm_handlers, entry) {
@@ -1618,10 +1658,7 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
 
     qemu_put_byte(f, QEMU_VM_EOF);
 
-    if (qemu_file_has_error(f))
-        return -EIO;
-
-    return 0;
+    return qemu_file_get_error(f);
 }
 
 void qemu_savevm_state_cancel(Monitor *mon, QEMUFile *f)
@@ -1637,12 +1674,8 @@ void qemu_savevm_state_cancel(Monitor *mon, QEMUFile *f)
 
 static int qemu_savevm_state(Monitor *mon, QEMUFile *f)
 {
-    int saved_vm_running;
     int ret;
 
-    saved_vm_running = runstate_is_running();
-    vm_stop(RUN_STATE_SAVE_VM);
-
     if (qemu_savevm_state_blocked(mon)) {
         ret = -EINVAL;
         goto out;
@@ -1661,11 +1694,9 @@ static int qemu_savevm_state(Monitor *mon, QEMUFile *f)
     ret = qemu_savevm_state_complete(mon, f);
 
 out:
-    if (qemu_file_has_error(f))
-        ret = -EIO;
-
-    if (!ret && saved_vm_running)
-        vm_start();
+    if (ret == 0) {
+        ret = qemu_file_get_error(f);
+    }
 
     return ret;
 }
@@ -1882,8 +1913,9 @@ out:
         g_free(le);
     }
 
-    if (qemu_file_has_error(f))
-        ret = -EIO;
+    if (ret == 0) {
+        ret = qemu_file_get_error(f);
+    }
 
     return ret;
 }