[Qemu-devel] [PULL v2 6/7] SMBIOS: Use bitmaps to prevent incompatible comand line options

[Gerd Hoffmann <kraxel@redhat.com>]

From: "Gabriel L. Somlo" <gsomlo@gmail.com>

Replace existing smbios_check_collision() functionality with
a pair of bitmaps: have_binfile_bitmap and have_fields_bitmap.
Bits corresponding to each smbios type are set by smbios_entry_add(),
which also uses the bitmaps to ensure that binary blobs and field
values are never accepted for the same type.

These bitmaps will also be used in the future to decide whether
or not to build a full table for a given smbios type.

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/i386/smbios.c         | 50 +++++++++++++++++++-----------------------------
 include/hw/i386/smbios.h |  2 ++
 2 files changed, 22 insertions(+), 30 deletions(-)

diff --git a/hw/i386/smbios.c b/hw/i386/smbios.c
index 9f83bfb..6bbfd15 100644
--- a/hw/i386/smbios.c
+++ b/hw/i386/smbios.c
@@ -51,11 +51,8 @@ static size_t smbios_entries_len;
 static int smbios_type4_count = 0;
 static bool smbios_immutable;
 
-static struct {
-    bool seen;
-    int headertype;
-    Location loc;
-} first_opt[2];
+static DECLARE_BITMAP(have_binfile_bitmap, SMBIOS_MAX_TYPE+1);
+static DECLARE_BITMAP(have_fields_bitmap, SMBIOS_MAX_TYPE+1);
 
 static struct {
     const char *vendor, *version, *date;
@@ -166,29 +163,6 @@ static void smbios_validate_table(void)
     }
 }
 
-/*
- * To avoid unresolvable overlaps in data, don't allow both
- * tables and fields for the same smbios type.
- */
-static void smbios_check_collision(int type, int entry)
-{
-    if (type < ARRAY_SIZE(first_opt)) {
-        if (first_opt[type].seen) {
-            if (first_opt[type].headertype != entry) {
-                error_report("Can't mix file= and type= for same type");
-                loc_push_restore(&first_opt[type].loc);
-                error_report("This is the conflicting setting");
-                loc_pop(&first_opt[type].loc);
-                exit(1);
-            }
-        } else {
-            first_opt[type].seen = true;
-            first_opt[type].headertype = entry;
-            loc_save(&first_opt[type].loc);
-        }
-    }
-}
-
 
 /* legacy setup functions for <= 2.0 machines */
 static void smbios_add_field(int type, int offset, const void *data, size_t len)
@@ -337,7 +311,14 @@ void smbios_entry_add(QemuOpts *opts)
         }
 
         header = (struct smbios_structure_header *)(table->data);
-        smbios_check_collision(header->type, SMBIOS_TABLE_ENTRY);
+
+        if (test_bit(header->type, have_fields_bitmap)) {
+            error_report("can't load type %d struct, fields already specified!",
+                         header->type);
+            exit(1);
+        }
+        set_bit(header->type, have_binfile_bitmap);
+
         if (header->type == 4) {
             smbios_type4_count++;
         }
@@ -352,7 +333,16 @@ void smbios_entry_add(QemuOpts *opts)
     if (val) {
         unsigned long type = strtoul(val, NULL, 0);
 
-        smbios_check_collision(type, SMBIOS_FIELD_ENTRY);
+        if (type > SMBIOS_MAX_TYPE) {
+            error_report("out of range!");
+            exit(1);
+        }
+
+        if (test_bit(type, have_binfile_bitmap)) {
+            error_report("can't add fields, binary file already loaded!");
+            exit(1);
+        }
+        set_bit(type, have_fields_bitmap);
 
         switch (type) {
         case 0:
diff --git a/include/hw/i386/smbios.h b/include/hw/i386/smbios.h
index 777e025..3a9361d 100644
--- a/include/hw/i386/smbios.h
+++ b/include/hw/i386/smbios.h
@@ -15,6 +15,8 @@
 
 #include "qemu/option.h"
 
+#define SMBIOS_MAX_TYPE 127
+
 void smbios_entry_add(QemuOpts *opts);
 void smbios_set_defaults(const char *manufacturer, const char *product,
                          const char *version);
-- 
1.8.3.1