From 3cdb9b5426ef508c9220b4b0316954e3b7dff9ac Mon Sep 17 00:00:00 2001
From: Hajime Yoshimori <lugia.kun@gmail.com>
Date: Fri, 1 May 2020 21:14:32 +0900
Subject: [PATCH 03/12] check return value of dladdr

https://github.com/dex4er/fakechroot/pull/70
---
 src/dladdr.c           | 12 +++++++-----
 test/Makefile.am       |  1 +
 test/src/Makefile.am   |  1 +
 test/src/test-dladdr.c | 14 ++++++++++++++
 test/t/dladdr.t        | 14 ++++++++++++++
 5 files changed, 37 insertions(+), 5 deletions(-)
 create mode 100644 test/src/test-dladdr.c
 create mode 100755 test/t/dladdr.t

diff --git a/src/dladdr.c b/src/dladdr.c
index fef3257..3dffdb3 100644
--- a/src/dladdr.c
+++ b/src/dladdr.c
@@ -36,11 +36,13 @@ wrapper(dladdr, int, (const void * addr, Dl_info * info))
 
     ret = nextcall(dladdr)(addr, info);
 
-    if (info->dli_fname) {
-        narrow_chroot_path(info->dli_fname);
-    }
-    if (info->dli_sname) {
-        narrow_chroot_path(info->dli_sname);
+    if (ret != 0) {
+        if (info->dli_fname) {
+            narrow_chroot_path(info->dli_fname);
+        }
+        if (info->dli_sname) {
+            narrow_chroot_path(info->dli_sname);
+        }
     }
 
     return ret;
diff --git a/test/Makefile.am b/test/Makefile.am
index aba2953..0021b0a 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -9,6 +9,7 @@ TESTS = \
     t/cmd-subst.t \
     t/cp.t \
     t/dedotdot.t \
+    t/dladdr.t \
     t/execlp.t \
     t/execve-elfloader.t \
     t/execve-null-envp.t \
diff --git a/test/src/Makefile.am b/test/src/Makefile.am
index 7fb3075..5f5fde8 100644
--- a/test/src/Makefile.am
+++ b/test/src/Makefile.am
@@ -3,6 +3,7 @@ check_PROGRAMS = \
     test-chroot \
     test-clearenv \
     test-dedotdot \
+    test-dladdr \
     test-execlp \
     test-execve-null-envp \
     test-fts \
diff --git a/test/src/test-dladdr.c b/test/src/test-dladdr.c
new file mode 100644
index 0000000..5ec8d24
--- /dev/null
+++ b/test/src/test-dladdr.c
@@ -0,0 +1,14 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+  Dl_info info;
+  memset(&info, 0xfe, sizeof(info)); /* fill with inaccessible address */
+  int ret = dladdr(NULL, &info);
+  printf("%ld\n", ret);
+  return 0;
+}
diff --git a/test/t/dladdr.t b/test/t/dladdr.t
new file mode 100755
index 0000000..fc7f939
--- /dev/null
+++ b/test/t/dladdr.t
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+srcdir=${srcdir:-.}
+. $srcdir/common.inc.sh
+
+prepare 1
+
+PATH=$srcdir/bin:$PATH
+
+t=`$srcdir/fakechroot.sh $testtree /bin/test-dladdr`
+[ "$t" != "0" ] && not
+ok "dladdr returns" $t
+
+cleanup
-- 
2.37.2