From a5d029ea6474db4f7edf8e9b6d73afd2ae583250 Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Tue, 22 Oct 2024 14:30:34 +0200
Subject: extracttar: Move large buffer to heap for valgrind

valgrind has some trouble on ppc64el with the large buffer, and
also on armhf where it seems to not understand the resulting
stack clash protector, so let's move it to the heap using simple
STL std::array in a std::unique_ptr.
---
 apt-pkg/contrib/extracttar.cc | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/apt-pkg/contrib/extracttar.cc b/apt-pkg/contrib/extracttar.cc
index 96cc513f0..dff9326a1 100644
--- a/apt-pkg/contrib/extracttar.cc
+++ b/apt-pkg/contrib/extracttar.cc
@@ -25,9 +25,11 @@
 #include <apt-pkg/strutl.h>
 
 #include <algorithm>
+#include <array>
 #include <csignal>
 #include <cstring>
 #include <iostream>
+#include <memory>
 #include <string>
 #include <fcntl.h>
 #include <unistd.h>
@@ -130,6 +132,7 @@ bool ExtractTar::Go(pkgDirStream &Stream)
    // Loop over all blocks
    string LastLongLink, ItemLink;
    string LastLongName, ItemName;
+   auto Junk = std::make_unique<std::array<unsigned char, 32*1024>>();
    while (1)
    {
       bool BadRecord = false;      
@@ -290,22 +293,21 @@ bool ExtractTar::Go(pkgDirStream &Stream)
       {
 	 // Copy the file over the FD
 	 auto Size = Itm.Size;
-	 unsigned char Junk[32*1024];
 	 do
 	 {
-	    auto const Read = std::min<unsigned long long>(Size, sizeof(Junk));
-	    if (not InFd.Read(Junk, ((Read + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	    auto const Read = std::min<unsigned long long>(Size, Junk->size());
+	    if (not InFd.Read(Junk->data(), ((Read + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
 	       return false;
 
 	    if (Fd > 0)
 	    {
-	       if (not FileFd::Write(Fd, Junk, Read))
+	       if (not FileFd::Write(Fd, Junk->data(), Read))
 		  return Stream.Fail(Itm, Fd);
 	    }
 	    // An Fd of -2 means to send to a special processing function
 	    else if (Fd == -2)
 	    {
-	       if (not Stream.Process(Itm, Junk, Read, Itm.Size - Size))
+	       if (not Stream.Process(Itm, Junk->data(), Read, Itm.Size - Size))
 		  return Stream.Fail(Itm, Fd);
 	    }
 
-- 
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