From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 31 Jul 2024 12:56:14 +0000 (+0100)
Subject: libstdc++: Handle strerror returning null
X-Git-Tag: basepoints/gcc-16~7102
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee4cc961ce399f2f3ac92fd711551677d61771da;p=thirdparty%2Fgcc.git

libstdc++: Handle strerror returning null

The linux man page for strerror says that some systems return NULL for
an unknown error number. That violates the C and POSIX standards, but we
can esily handle it to avoid a segfault.

libstdc++-v3/ChangeLog:

	* src/c++11/system_error.cc (strerror_string): Handle
	non-conforming NULL return from strerror.
---

diff --git a/libstdc++-v3/src/c++11/system_error.cc b/libstdc++-v3/src/c++11/system_error.cc
index d01451ba1ef..38bc0446110 100644
--- a/libstdc++-v3/src/c++11/system_error.cc
+++ b/libstdc++-v3/src/c++11/system_error.cc
@@ -110,7 +110,11 @@ namespace
 #else
   string strerror_string(int err)
   {
-    return strerror(err); // XXX Not thread-safe.
+    auto str = strerror(err); // XXX Not thread-safe.
+    if (str) [[__likely__]]
+      return str;
+    // strerror should not return NULL, but some implementations do.
+    return "Unknown error";
   }
 #endif