Strip trailing garbage in tar files to avoid SIGPIPEs

4 files changed, 118 insertions, 6 deletions

diff --git a/.gitignore b/.gitignore
index 5160765..f17dfc9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -328,6 +328,7 @@ paludis-*.*.*.tar.bz2
 /paludis/repositories/e/ebuild/utils/prepman
 /paludis/repositories/e/ebuild/utils/prepstrip
 /paludis/repositories/e/ebuild/utils/print_exports
+/paludis/repositories/e/ebuild/utils/strip_tar_corruption
 /paludis/repositories/e/ebuild/utils/unpaxinate
 /paludis/repositories/e/exndbam_repository_TEST
 /paludis/repositories/e/fetch_visitor_TEST
diff --git a/paludis/repositories/e/ebuild/utils/Makefile.am b/paludis/repositories/e/ebuild/utils/Makefile.am
index 934337a..53c3135 100644
--- a/paludis/repositories/e/ebuild/utils/Makefile.am
+++ b/paludis/repositories/e/ebuild/utils/Makefile.am
@@ -59,7 +59,8 @@ libexecprog_SCRIPTS = \
 libexecbindir = $(libexecdir)/paludis/utils
 libexecbin_PROGRAMS = \
 	print_exports \
-	locked_pipe_command
+	locked_pipe_command \
+	strip_tar_corruption
 
 if ENABLE_PBINS
 libexecbin_PROGRAMS += \
@@ -73,6 +74,7 @@ endif
 
 print_exports_SOURCES = print_exports.cc
 locked_pipe_command_SOURCES = locked_pipe_command.cc
+strip_tar_corruption_SOURCES = strip_tar_corruption.cc
 
 AM_CXXFLAGS = -I$(top_srcdir) @PALUDIS_CXXFLAGS@
 
diff --git a/paludis/repositories/e/ebuild/utils/strip_tar_corruption.cc b/paludis/repositories/e/ebuild/utils/strip_tar_corruption.cc
new file mode 100644
index 0000000..46ac176
--- /dev/null
+++ b/paludis/repositories/e/ebuild/utils/strip_tar_corruption.cc
@@ -0,0 +1,108 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2012 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <cstdlib>
+
+int main(int, char * argv[])
+{
+    char buf[512];
+    uint64_t records_to_skip(0);
+    int zero_records(0);
+    while (std::cin.read(buf, 512))
+    {
+        int bufn(std::cin.gcount());
+        if (bufn < 512)
+        {
+            std::cout.write(buf, bufn);
+            std::cerr << argv[0] << ": Unexpectedly short tar file" << std::endl;
+            return EXIT_FAILURE;
+        }
+
+        if (records_to_skip > 0)
+        {
+            --records_to_skip;
+            std::cout.write(buf, 512);
+            continue;
+        }
+
+        if (std::string::npos == std::string(buf, 512).find_first_not_of(std::string("\0", 1)))
+        {
+            if (zero_records < 2)
+                std::cout.write(buf, 512);
+            ++zero_records;
+            continue;
+        }
+
+        if (zero_records > 0)
+        {
+            if (zero_records >= 2)
+            {
+                if (std::string(buf, 8) == std::string("\xa6\x4c\x32\x2e\xd6\x14\xae\xdb"))
+                    std::cerr << argv[0] << ": Found trailing corruption from pixz after "
+                        << zero_records << " zero records, discarding it" << std::endl;
+                else
+                    std::cerr << argv[0] << ": Found trailing corruption in an unrecognised format after "
+                        << zero_records << " zero records, discarding it" << std::endl;
+            }
+            else
+                std::cerr << argv[0] << ": Found trailing corruption after a single zero record, discarding it" << std::endl;
+
+            while (std::cin.read(buf, 512))
+            {
+                /* nothing */
+            }
+
+            return EXIT_SUCCESS;
+        }
+
+        zero_records = 0;
+
+        switch (buf[156])
+        {
+            case '2': case '3': case '4': case '5': case '6':
+                records_to_skip = 0;
+                break;
+
+            default:
+                {
+                    std::string s(&buf[124], 12);
+                    std::stringstream ss(s);
+                    if (! (ss >> std::oct >> records_to_skip))
+                    {
+                        std::cerr << argv[0] << ": Unable to determine how many records to skip from '" << s << "'" << std::endl;
+                        return EXIT_FAILURE;
+                    }
+
+                    records_to_skip = (records_to_skip + 511) / 512;
+                }
+        }
+
+        std::cout.write(buf, 512);
+    }
+
+    if (zero_records < 2)
+        std::cerr << argv[0] << ": tar file does not include an EOF marker" << std::endl;
+
+    return EXIT_SUCCESS;
+}
+
+
diff --git a/paludis/repositories/e/ebuild/utils/unpack b/paludis/repositories/e/ebuild/utils/unpack
index 45ff590..aebe57c 100755
--- a/paludis/repositories/e/ebuild/utils/unpack
+++ b/paludis/repositories/e/ebuild/utils/unpack
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # vim: set sw=4 sts=4 et :
 
-# Copyright (c) 2006, 2007, 2008 Ciaran McCreesh
+# Copyright (c) 2006, 2007, 2008, 2011 Ciaran McCreesh
 #
 # Based in part upon ebuild.sh from Portage, which is Copyright 1995-2005
 # Gentoo Foundation and distributed under the terms of the GNU General
@@ -30,6 +30,7 @@ die()
     fi
     exit 123
 }
+
 assert()
 {
     local _pipestatus="${PIPESTATUS[*]}"
@@ -82,8 +83,8 @@ unpack_a() {
 }
 
 unpack_tar.lzma() {
-    echo lzma -dc "${1}" \| tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
-    lzma -dc "${1}" | tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
+    echo lzma -dc "${1}" \| strip_tar_corruption \| tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
+    lzma -dc "${1}" | strip_tar_corruption | tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
     assert "Couldn't unpack ${1}"
 }
 
@@ -98,8 +99,8 @@ unpack_7z() {
 }
 
 unpack_tar.xz() {
-    echo xz -dc "${1}" \| tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
-    xz -dc "${1}" | tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
+    echo xz -dc "${1}" \| strip_tar_corruption \| tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
+    xz -dc "${1}" | strip_tar_corruption | tar xf - --no-same-owner "${TAR_OPTIONS[@]}"
     assert "Couldn't unpack ${1}"
 }