From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Keith Seitz <keiths@redhat.com>

Date: Mon, 27 Jul 2020 19:21:54 -0400

Subject: gdb-rhbz1842691-corefile-mem-access-9of15.patch

;; Add test for accessing read-only mmapped data in a core file

;; Kevin Buettner, RH BZ 1842691

   Author: Kevin Buettner <kevinb@redhat.com>

   Date:   Tue Jun 16 11:39:22 2020 -0700

    Add test for accessing read-only mmapped data in a core file

    This test passes when run using a GDB with my corefile patches.  When

    run against a GDB without my patches, I see the following failures,

    the first of which is due to the test added by this commit:

    FAIL: gdb.base/corefile.exp: accessing read-only mmapped data in core file (

    FAIL: gdb.base/corefile.exp: accessing anonymous, unwritten-to mmap data

    gdb/testsuite/ChangeLog:

        * gdb.base/corefile.exp: Add test "accessing read-only mmapped

        data in core file".

        * gdb.base/coremaker.c (buf2ro): New global.

        (mmapdata): Add a read-only mmap mapping.

diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp

--- a/gdb/testsuite/gdb.base/corefile.exp

+++ b/gdb/testsuite/gdb.base/corefile.exp

@@ -34,7 +34,10 @@ if {[build_executable $testfile.exp $testfile $srcfile debug] == -1} {

     return -1

 }

-set corefile [core_find $binfile {coremmap.data}]

+# Do not delete coremap.data when calling core_find.  This file is

+# required for GDB to find mmap'd data in the "accessing read-only

+# mmapped data in core file" test.

+set corefile [core_find $binfile {}]

 if {$corefile == ""} {

     return 0

 }

@@ -175,6 +178,19 @@ gdb_test_multiple "x/8bd buf2" "$test" {

     }

 }

+set test "accessing read-only mmapped data in core file"

+gdb_test_multiple "x/8bd buf2ro" "$test" {

+    -re ".*:.*0.*1.*2.*3.*4.*5.*6.*7.*$gdb_prompt $" {

+	pass "$test"

+    }

+    -re "0x\[f\]*:.*Cannot access memory at address 0x\[f\]*.*$gdb_prompt $" {

+	fail "$test (mapping failed at runtime)"

+    }

+    -re "0x.*:.*Cannot access memory at address 0x.*$gdb_prompt $" {

+	fail "$test (mapping address not found in core file)"

+    }

+}

+

 # Test ability to read anonymous and, more importantly, unwritten-to

 # mmap'd data.

diff --git a/gdb/testsuite/gdb.base/coremaker.c b/gdb/testsuite/gdb.base/coremaker.c

--- a/gdb/testsuite/gdb.base/coremaker.c

+++ b/gdb/testsuite/gdb.base/coremaker.c

@@ -38,6 +38,7 @@

 char *buf1;

 char *buf2;

+char *buf2ro;

 char *buf3;

 int coremaker_data = 1;	/* In Data section */

@@ -90,16 +91,25 @@ mmapdata ()

       return;

     }

+  /* Map in another copy, read-only.  We won't write to this copy so it

+     will likely not end up in the core file.  */

+  buf2ro = (char *) mmap (0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);

+  if (buf2ro == (char *) -1)

+    {

+      perror ("mmap failed");

+      return;

+    }

+

   /* Verify that the original data and the mapped data are identical.

      If not, we'd rather fail now than when trying to access the mapped

      data from the core file. */

   for (j = 0; j < MAPSIZE; ++j)

     {

-      if (buf1[j] != buf2[j])

+      if (buf1[j] != buf2[j] || buf1[j] != buf2ro[j])

 	{

 	  fprintf (stderr, "mapped data is incorrect");

-	  buf2 = (char *) -1;

+	  buf2 = buf2ro = (char *) -1;

 	  return;

 	}

     }