kconfig: search for a config to base the local(mod|yes)config on

Instead of using the .config in the local directory. This patch
changes streamline_config.pl to search various locations for a config.

Here's the list and order of search:

  /proc/config.gz
  /boot/vmlinuz-`uname -r`
  vmlinux  # local to the directory
  /lib/modules/`uname -r`/kernel/kernel/configs.ko
  kernel/configs.ko
  kernel/configs.o
  .config

Once it finds a file that contains a config (it checks if the binary
objects have configs first) it then uses it to create the .config
with minimum modules needed.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 62 insertions, 1 deletions

diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl
index 233464185a92..9fa3f81b1ed9 100644
--- a/scripts/kconfig/streamline_config.pl
+++ b/scripts/kconfig/streamline_config.pl
@@ -45,7 +45,68 @@
 my $config = ".config";
 my $linuxpath = ".";
 
-open(CIN,$config) || die "Can't open current config file: $config";
+my $uname = `uname -r`;
+chomp $uname;
+
+my @searchconfigs = (
+        {
+            "file" => "/proc/config.gz",
+            "exec" => "zcat",
+        },
+        {
+            "file" => "/boot/vmlinuz-$uname",
+            "exec" => "scripts/extract-ikconfig",
+            "test" => "scripts/extract-ikconfig",
+        },
+        {
+            "file" => "vmlinux",
+            "exec" => "scripts/extract-ikconfig",
+            "test" => "scripts/extract-ikconfig",
+        },
+        {
+            "file" => "/lib/modules/$uname/kernel/kernel/configs.ko",
+            "exec" => "scripts/extract-ikconfig",
+            "test" => "scripts/extract-ikconfig",
+        },
+        {
+            "file" => "kernel/configs.ko",
+            "exec" => "scripts/extract-ikconfig",
+            "test" => "scripts/extract-ikconfig",
+        },
+        {
+            "file" => "kernel/configs.o",
+            "exec" => "scripts/extract-ikconfig",
+            "test" => "scripts/extract-ikconfig",
+        },
+        {
+            "file" => ".config",
+            "exec" => "cat",
+        },
+);
+
+sub find_config {
+    foreach my $conf (@searchconfigs) {
+        my $file = $conf->{"file"};
+
+        next if ( ! -f "$file");
+
+        if (defined($conf->{"test"})) {
+            `$conf->{"test"} $conf->{"file"} 2>/dev/null`;
+            next if ($?);
+        }
+
+        my $exec = $conf->{"exec"};
+
+        print STDERR "using config: '$file'\n";
+
+        open(CIN, "$exec $file |") || die "Failed to run $exec $file";
+        return;
+    }
+    die "No config file found";
+}
+
+find_config;
+
 my @makefiles = `find $linuxpath -name Makefile`;
 my %depends;
 my %selects;