Ignore ownership and permissions of files in OTP source archives

When run as root in some environments (such as Kaniko build in Docker
executor in GitLab CI), Tar tries to set extracted files' uid, gid,
suid, sgid, etc exactly as in the archive. This process can fail,
because the build system might not have them.

kerl

@@ -466,6 +466,12 @@ _curl() {
     \curl -q --silent --location --fail $2 $3 $_curl_extra
 }
 
+unpack() {
+    # $1: <file> to extract to current directory
+
+    tar -x --no-same-owner --no-same-permissions -zf "$1"
+}
+
 get_tarball_releases() {
     tmp="$(mktemp "$TMP_DIR"/kerl.XXXXXX)"
     notice "Getting releases from erlang.org..."
@@ -818,7 +824,7 @@ do_normal_build() {
         # github tarballs have a directory in the form of "otp[_-]TAGNAME"
         # Ericsson tarballs have the classic otp_src_RELEASE pattern
         # Standardize on Ericsson format because that's what the rest of the script expects
-        (cd "$UNTARDIRNAME" && tar xzf "$KERL_DOWNLOAD_DIR/$FILENAME".tar.gz &&
+        (cd "$UNTARDIRNAME" && unpack "$KERL_DOWNLOAD_DIR/$FILENAME".tar.gz &&
             cp -rfp ./* "$_KERL_BUILD_DIR/otp_src_$1")
         rm -rf "$UNTARDIRNAME"
     fi
@@ -1786,7 +1792,7 @@ download_manpages() {
         return 1
     fi
     notice "Extracting man pages..."
-    (cd "$absdir" && tar xzf "$KERL_DOWNLOAD_DIR/$FILENAME")
+    (cd "$absdir" && unpack "$KERL_DOWNLOAD_DIR/$FILENAME")
 }
 
 download_htmldocs() {
@@ -1795,7 +1801,7 @@ download_htmldocs() {
         return 1
     fi
     notice "Extracting HTML docs..."
-    (cd "$absdir" && mkdir -p html && tar -C "$absdir"/html -xzf "$KERL_DOWNLOAD_DIR/$FILENAME")
+    (cd "$absdir" && mkdir -p html && cd html && unpack "$KERL_DOWNLOAD_DIR/$FILENAME")
 }
 
 build_plt() {