[Qemu-devel] [PATCH v2 1/2] accomodate OpenFirmware device paths in sufficient storage

[Laszlo Ersek <lersek@redhat.com>]

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/qdev.c |   54 +++++++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/hw/qdev.c b/hw/qdev.c
index af54467..59cc0c2 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -25,6 +25,8 @@
    inherit from a particular bus (e.g. PCI or I2C) rather than
    this API directly.  */
 
+#include <stdarg.h>
+
 #include "net.h"
 #include "qdev.h"
 #include "sysemu.h"
@@ -495,36 +497,66 @@ static char *bus_get_fw_dev_path(BusState *bus, DeviceState *dev)
     return NULL;
 }
 
+static int snprintf_helper(char *p, int size, int len, const char *format, ...)
+{
+    char *target;
+    int free_sz;
+    va_list args;
+    int ret;
+
+    if (len < size) {
+        target = p + len;
+        free_sz = size - len;
+    }
+    else {
+        target = NULL;
+        free_sz = 0;
+    }
+
+    va_start(args, format);
+    ret = vsnprintf(target, free_sz, format, args);
+    va_end(args);
+
+    assert(ret >= 0);
+    return ret;
+}
+
+
 static int qdev_get_fw_dev_path_helper(DeviceState *dev, char *p, int size)
 {
-    int l = 0;
+    int len = 0;
 
     if (dev && dev->parent_bus) {
         char *d;
-        l = qdev_get_fw_dev_path_helper(dev->parent_bus->parent, p, size);
+        len = qdev_get_fw_dev_path_helper(dev->parent_bus->parent, p, size);
         d = bus_get_fw_dev_path(dev->parent_bus, dev);
         if (d) {
-            l += snprintf(p + l, size - l, "%s", d);
+            len += snprintf_helper(p, size, len, "%s", d);
             g_free(d);
         } else {
-            l += snprintf(p + l, size - l, "%s", object_get_typename(OBJECT(dev)));
+            len += snprintf_helper(p, size, len, "%s",
+                                   object_get_typename(OBJECT(dev)));
         }
     }
-    l += snprintf(p + l , size - l, "/");
+    len += snprintf_helper(p, size, len, "/");
 
-    return l;
+    return len;
 }
 
 char* qdev_get_fw_dev_path(DeviceState *dev)
 {
-    char path[128];
-    int l;
+    int len, len2;
+    char *path;
 
-    l = qdev_get_fw_dev_path_helper(dev, path, 128);
+    len = qdev_get_fw_dev_path_helper(dev, NULL, 0);
+    path = g_malloc(len + 1);
 
-    path[l-1] = '\0';
+    len2 = qdev_get_fw_dev_path_helper(dev, path, len + 1);
+    assert(len2 == len);
 
-    return strdup(path);
+    assert(len > 0);
+    path[len - 1] = '\0';
+    return path;
 }
 
 char *qdev_get_dev_path(DeviceState *dev)
-- 
1.7.1