disas: use result of ->read_memory_func

This gets especially confusing if you start plugging in host addresses
from a trace and you wonder why the output keeps changing. Report when
read_memory_func fails instead of blindly disassembling the buffer
contents.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220929114231.583801-35-alex.bennee@linaro.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/disas.c b/disas.c
index f07b6e760b..94d3b45042 100644
--- a/disas.c
+++ b/disas.c
@@ -83,18 +83,18 @@ static int print_insn_objdump(bfd_vma pc, disassemble_info *info,
                               const char *prefix)
 {
     int i, n = info->buffer_length;
-    uint8_t *buf = g_malloc(n);
-
-    info->read_memory_func(pc, buf, n, info);
-
-    for (i = 0; i < n; ++i) {
-        if (i % 32 == 0) {
-            info->fprintf_func(info->stream, "\n%s: ", prefix);
+    g_autofree uint8_t *buf = g_malloc(n);
+
+    if (info->read_memory_func(pc, buf, n, info) == 0) {
+        for (i = 0; i < n; ++i) {
+            if (i % 32 == 0) {
+                info->fprintf_func(info->stream, "\n%s: ", prefix);
+            }
+            info->fprintf_func(info->stream, "%02x", buf[i]);
         }
-        info->fprintf_func(info->stream, "%02x", buf[i]);
+    } else {
+        info->fprintf_func(info->stream, "unable to read memory");
     }
-
-    g_free(buf);
     return n;
 }