elf2dmp: rework PDB_STREAM_INDEXES::segments obtaining

PDB for Windows 11 kernel has slightly different structure compared to
previous versions. Since elf2dmp don't use the other fields, copy only
'segments' field from PDB_STREAM_INDEXES.

Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20230915170153.10959-6-viktor@daynix.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

contrib/elf2dmp/pdb.c

@@ -160,7 +160,7 @@ static void *pdb_ds_read_file(struct pdb_reader* r, uint32_t file_number)
 static int pdb_init_segments(struct pdb_reader *r)
 {
     char *segs;
-    unsigned stream_idx = r->sidx.segments;
+    unsigned stream_idx = r->segments;
 
     segs = pdb_ds_read_file(r, stream_idx);
     if (!segs) {
@@ -177,9 +177,6 @@ static int pdb_init_symbols(struct pdb_reader *r)
 {
     int err = 0;
     PDB_SYMBOLS *symbols;
-    PDB_STREAM_INDEXES *sidx = &r->sidx;
-
-    memset(sidx, -1, sizeof(*sidx));
 
     symbols = pdb_ds_read_file(r, 3);
     if (!symbols) {
@@ -188,15 +185,11 @@ static int pdb_init_symbols(struct pdb_reader *r)
 
     r->symbols = symbols;
 
-    if (symbols->stream_index_size != sizeof(PDB_STREAM_INDEXES)) {
-        err = 1;
-        goto out_symbols;
-    }
-
-    memcpy(sidx, (const char *)symbols + sizeof(PDB_SYMBOLS) +
+    r->segments = *(uint16_t *)((const char *)symbols + sizeof(PDB_SYMBOLS) +
             symbols->module_size + symbols->offset_size +
             symbols->hash_size + symbols->srcmodule_size +
-            symbols->pdbimport_size + symbols->unknown2_size, sizeof(*sidx));
+            symbols->pdbimport_size + symbols->unknown2_size +
+            offsetof(PDB_STREAM_INDEXES, segments));
 
     /* Read global symbol table */
     r->modimage = pdb_ds_read_file(r, symbols->gsym_file);

contrib/elf2dmp/pdb.h

@@ -227,7 +227,7 @@ struct pdb_reader {
     } ds;
     uint32_t file_used[1024];
     PDB_SYMBOLS *symbols;
-    PDB_STREAM_INDEXES sidx;
+    uint16_t segments;
     uint8_t *modimage;
     char *segs;
     size_t segs_size;