migration: use ERROR_INT() (#432)

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

4 files changed, 35 insertions, 31 deletions

diff --git a/include/libvfio-user.h b/include/libvfio-user.h
index fa21bc2..d1c30e4 100644
--- a/include/libvfio-user.h
+++ b/include/libvfio-user.h
@@ -495,7 +495,7 @@ typedef struct {
     /*
      * Migration state transition callback.
      *
-     * Returns -1 on error, setting errno.
+     * The callback should return -1 on error, setting errno.
      *
      * TODO rename to vfu_migration_state_transition_callback
      * FIXME maybe we should create a single callback and pass the state?
@@ -524,6 +524,8 @@ typedef struct {
      *
      * When in resuming state, @offset must be set to where migration data must
      * written. @size points to NULL.
+     *
+     * The callback should return -1 on error, setting errno.
      */
     int (*prepare_data)(vfu_ctx_t *vfu_ctx, uint64_t *offset, uint64_t *size);
 
@@ -554,6 +556,8 @@ typedef struct {
     /*
      * Function that is called when client has written some previously stored
      * device state.
+     *
+     * The callback should return -1 on error, setting errno.
      */
     int (*data_written)(vfu_ctx_t *vfu_ctx, uint64_t count);
 
diff --git a/lib/libvfio-user.c b/lib/libvfio-user.c
index 47d0651..0d8a310 100644
--- a/lib/libvfio-user.c
+++ b/lib/libvfio-user.c
@@ -221,6 +221,9 @@ region_access(vfu_ctx_t *vfu_ctx, size_t region_index, char *buf,
         }
     } else if (is_migr_reg(vfu_ctx, region_index) && vfu_ctx->migration != NULL) {
         ret = migration_region_access(vfu_ctx, buf, count, offset, is_write);
+        if (ret == -1) {
+            ret = -errno;
+        }
     } else {
         vfu_region_access_cb_t *cb = vfu_ctx->reg_info[region_index].cb;
 
diff --git a/lib/migration.c b/lib/migration.c
index ff6913b..899a8c4 100644
--- a/lib/migration.c
+++ b/lib/migration.c
@@ -122,7 +122,7 @@ handle_device_state(vfu_ctx_t *vfu_ctx, struct migration *migr,
 
     if (*device_state & ~VFIO_DEVICE_STATE_MASK) {
         vfu_log(vfu_ctx, LOG_ERR, "bad device state %#x", *device_state);
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     if (!vfio_migr_state_transition_is_valid(migr->info.device_state,
@@ -130,7 +130,7 @@ handle_device_state(vfu_ctx_t *vfu_ctx, struct migration *migr,
         vfu_log(vfu_ctx, LOG_ERR, "bad transition from state %s to state %s",
                migr_states[migr->info.device_state].name,
                migr_states[*device_state].name);
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     switch (*device_state) {
@@ -164,8 +164,8 @@ handle_device_state(vfu_ctx_t *vfu_ctx, struct migration *migr,
         migr->info.device_state = *device_state;
         migr_state_transition(migr, VFIO_USER_MIGR_ITER_STATE_INITIAL);
     } else if (ret < 0) {
-        vfu_log(vfu_ctx, LOG_ERR, "failed to transition to state %d: %s",
-                *device_state, strerror(-ret));
+        vfu_log(vfu_ctx, LOG_ERR, "failed to transition to state %d: %m",
+                *device_state);
     }
 
     return ret;
@@ -181,7 +181,7 @@ handle_pending_bytes(vfu_ctx_t *vfu_ctx, struct migration *migr,
     assert(pending_bytes != NULL);
 
     if (is_write) {
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     if (migr->iter.state == VFIO_USER_MIGR_ITER_STATE_FINISHED) {
@@ -213,7 +213,7 @@ handle_pending_bytes(vfu_ctx_t *vfu_ctx, struct migration *migr,
             *pending_bytes = migr->iter.pending_bytes;
             break;
         default:
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
     }
     return 0;
 }
@@ -235,7 +235,7 @@ handle_data_offset_when_saving(vfu_ctx_t *vfu_ctx, struct migration *migr,
 
     if (is_write) {
         vfu_log(vfu_ctx, LOG_ERR, "data_offset is RO when saving");
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     switch (migr->iter.state) {
@@ -262,7 +262,7 @@ handle_data_offset_when_saving(vfu_ctx_t *vfu_ctx, struct migration *migr,
     default:
         vfu_log(vfu_ctx, LOG_ERR,
                 "reading data_offset out of sequence is undefined");
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     return 0;
@@ -289,7 +289,7 @@ handle_data_offset(vfu_ctx_t *vfu_ctx, struct migration *migr,
         if (is_write) {
             /* TODO writing to read-only registers should be simply ignored */
             vfu_log(vfu_ctx, LOG_ERR, "bad write to migration data_offset");
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
         ret = migr->callbacks.prepare_data(vfu_ctx, offset, NULL);
         if (ret < 0) {
@@ -302,7 +302,7 @@ handle_data_offset(vfu_ctx_t *vfu_ctx, struct migration *migr,
     vfu_log(vfu_ctx, LOG_ERR,
             "bad access to migration data_offset in state %s",
             migr_states[migr->info.device_state].name);
-    return -EINVAL;
+    return ERROR_INT(EINVAL);
 }
 
 static ssize_t
@@ -314,14 +314,14 @@ handle_data_size_when_saving(vfu_ctx_t *vfu_ctx, struct migration *migr,
     if (is_write) {
         /* TODO improve error message */
         vfu_log(vfu_ctx, LOG_ERR, "data_size is RO when saving");
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     if (migr->iter.state != VFIO_USER_MIGR_ITER_STATE_STARTED &&
         migr->iter.state != VFIO_USER_MIGR_ITER_STATE_DATA_PREPARED) {
         vfu_log(vfu_ctx, LOG_ERR,
                 "reading data_size ouf of sequence is undefined");
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
     return 0;
 }
@@ -360,7 +360,7 @@ handle_data_size(vfu_ctx_t *vfu_ctx, struct migration *migr,
     }
     /* TODO improve error message */
     vfu_log(vfu_ctx, LOG_ERR, "bad access to data_size");
-    return -EINVAL;
+    return ERROR_INT(EINVAL);
 }
 
 static ssize_t
@@ -377,7 +377,7 @@ migration_region_access_registers(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
         if (count != sizeof(migr->info.device_state)) {
             vfu_log(vfu_ctx, LOG_ERR,
                     "bad device_state access size %ld", count);
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
         ret = handle_device_state(vfu_ctx, migr, (uint32_t *)buf, is_write);
         break;
@@ -385,7 +385,7 @@ migration_region_access_registers(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
         if (count != sizeof(migr->info.pending_bytes)) {
             vfu_log(vfu_ctx, LOG_ERR,
                     "bad pending_bytes access size %ld", count);
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
         ret = handle_pending_bytes(vfu_ctx, migr, (uint64_t *)buf, is_write);
         break;
@@ -393,7 +393,7 @@ migration_region_access_registers(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
         if (count != sizeof(migr->info.data_offset)) {
             vfu_log(vfu_ctx, LOG_ERR,
                     "bad data_offset access size %ld", count);
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
         ret = handle_data_offset(vfu_ctx, migr, (uint64_t *)buf, is_write);
         break;
@@ -401,14 +401,14 @@ migration_region_access_registers(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
         if (count != sizeof(migr->info.data_size)) {
             vfu_log(vfu_ctx, LOG_ERR,
                     "bad data_size access size %ld", count);
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
         ret = handle_data_size(vfu_ctx, migr, (uint64_t *)buf, is_write);
         break;
     default:
         vfu_log(vfu_ctx, LOG_ERR, "bad migration region register offset %#lx",
                pos);
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
     return ret;
 }
@@ -418,7 +418,7 @@ migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
                         loff_t pos, bool is_write)
 {
     struct migration *migr = vfu_ctx->migration;
-    ssize_t ret = -EINVAL;
+    ssize_t ret;
 
     assert(migr != NULL);
     assert(buf != NULL);
@@ -442,14 +442,14 @@ migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
             vfu_log(vfu_ctx, LOG_WARNING,
                     "bad access to dead space %#lx-%#lx in migration region",
                     pos, pos + count - 1);
-            return -EINVAL;
+            return ERROR_INT(EINVAL);
         }
 
         pos -= migr->data_offset;
         if (is_write) {
             ret = migr->callbacks.write_data(vfu_ctx, buf, count, pos);
-            if (ret == -1) {
-                ret = -errno;
+            if (ret < 0) {
+                return -1;
             }
         } else {
             /*
@@ -461,16 +461,13 @@ migration_region_access(vfu_ctx_t *vfu_ctx, char *buf, size_t count,
              * Does this mean that partial reads are not allowed?
              */
             ret = migr->callbacks.read_data(vfu_ctx, buf, count, pos);
-            if (ret == -1) {
-                ret = -errno;
+            if (ret < 0) {
+                return -1;
             }
         }
     }
 
-    if (ret == 0) {
-        ret = count;
-    }
-    return ret;
+    return count;
 }
 
 bool
@@ -500,7 +497,7 @@ migration_set_pgsize(struct migration *migr, size_t pgsize)
 
     // FIXME?
     if (pgsize != PAGE_SIZE) {
-        return -EINVAL;
+        return ERROR_INT(EINVAL);
     }
 
     migr->pgsize = pgsize;
diff --git a/lib/tran_sock.c b/lib/tran_sock.c
index 868a5be..3785e67 100644
--- a/lib/tran_sock.c
+++ b/lib/tran_sock.c
@@ -620,7 +620,7 @@ recv_version(vfu_ctx_t *vfu_ctx, int sock, uint16_t *msg_idp,
             if (ret != 0) {
                 vfu_log(vfu_ctx, LOG_ERR, "refusing client page size of %zu",
                         pgsize);
-                ret = -ret;
+                ret = errno;
                 goto out;
             }
         }