move all our stuff into /lkmc in guest

Motivation: userland is getting several new subdirectories, it would be
too insane to just dump all of that in the guest root filesystem.

To alleviate the cd pain, .profile puts user inside /lkmc by default.

.gitignore

@@ -2,8 +2,8 @@
 *.tmp
 tmp.*
 *~
-?*.gitignore
+*.gitignore
-gitignore*
+gitignore.*
 
 # Specific files.
 /data

build-linux

@@ -209,7 +209,7 @@ Run `make modules_install` after `make`.
                     (
                         common_make_args +
                         [
-                            'INSTALL_MOD_PATH={}'.format(self.env['out_rootfs_overlay_dir']), LF,
+                            'INSTALL_MOD_PATH={}'.format(self.env['out_rootfs_overlay_lkmc_dir']), LF,
                             'modules_install', LF,
                         ]
                     ),

build-modules

@@ -108,7 +108,7 @@ Place the modules on a separate magic directory from non --host builds.
         if not self.env['host']:
             self.sh.copy_dir_if_update_non_recursive(
                 srcdir=self.env['kernel_modules_build_subdir'],
-                destdir=self.env['out_rootfs_overlay_dir'],
+                destdir=self.env['out_rootfs_overlay_lkmc_dir'],
                 filter_ext=self.env['kernel_module_ext'],
             )
 

build-userland

@@ -335,7 +335,7 @@ Default: build all examples that have their package dependencies met, e.g.:
             return 1
         self.sh.copy_dir_if_update(
             srcdir=build_dir,
-            destdir=self.env['out_rootfs_overlay_dir'],
+            destdir=self.env['out_rootfs_overlay_lkmc_dir'],
             filter_ext=self.env['userland_build_ext'],
         )
         return 0

common.py

@@ -724,8 +724,12 @@ Valid emulators: {}
         env['kernel_modules_build_subdir'] = join(env['kernel_modules_build_dir'], env['kernel_modules_subdir'])
         env['kernel_modules_build_host_dir'] = join(env['kernel_modules_build_base_dir'], 'host')
         env['kernel_modules_build_host_subdir'] = join(env['kernel_modules_build_host_dir'], env['kernel_modules_subdir'])
+
+        # Overlay.
         env['out_rootfs_overlay_dir'] = join(env['out_dir'], 'rootfs_overlay', env['arch'])
-        env['out_rootfs_overlay_bin_dir'] = join(env['out_rootfs_overlay_dir'], 'bin')
+        env['out_rootfs_overlay_lkmc_dir'] = join(env['out_rootfs_overlay_dir'], 'lkmc')
+        env['out_rootfs_overlay_bin_dir'] = join(env['out_rootfs_overlay_lkmc_dir'], 'bin')
+        env['guest_lkmc_home'] = os.sep + 'lkmc'
 
         # Baremetal.
         env['baremetal_source_dir'] = join(env['root_dir'], 'baremetal')

copy-overlay

@@ -15,12 +15,9 @@ https://github.com/cirosantilli/linux-kernel-module-cheat#rootfs_overlay
 ''')
 
     def build(self):
-        # TODO: print rsync equivalent, move into shell_helpers.
+        self.sh.copy_dir_if_update(
-        distutils.dir_util.copy_tree(
+            srcdir=self.env['rootfs_overlay_dir'],
-            self.env['rootfs_overlay_dir'],
+            destdir=self.env['out_rootfs_overlay_dir'],
-            self.env['out_rootfs_overlay_dir'],
-            preserve_symlinks=True,
-            update=1,
         )
 
 if __name__ == '__main__':

rootfs_overlay/.profile

@@ -0,0 +1,4 @@
+# https://github.com/cirosantilli/linux-kernel-module-cheat#busybox-shell-initrc-files
+echo "hello .profile"
+export PS1='\w\n\u@\h# '
+cd /lkmc

rootfs_overlay/conf.sh

@@ -1,2 +0,0 @@
-#!/bin/sh
-zcat /proc/config.gz | grep -Ei "${1:-}"

rootfs_overlay/etc/init.d/S98

@@ -1,5 +1,7 @@
 #!/bin/sh
+# https://github.com/cirosantilli/linux-kernel-module-cheat#init-busybox
 echo "hello S98"
+cd "$lkmc_home"
 if [ -n "$lkmc_eval" ]; then
   eval "$lkmc_eval"
 elif [ -n "$lkmc_eval_base64" ]; then

rootfs_overlay/eval.sh

@@ -1,18 +0,0 @@
-#!/bin/sh
-echo "$lkmc_eval"
-eval "$lkmc_eval"
-
-# Ideally, this script would do just:
-#
-## Get rid of the '-'.
-#shift
-#echo "$@"
-#
-# However, the kernel CLI parsing is crap, and the 4.14 docs lie.
-#
-# In particular, not all that is passed after "-" goes to an argument to init,
-# e.g. stuff with dots like "- ./poweroff.out" still gets treated specially and
-# does not go to init.
-#
-# This also likely means that the above solution is also unreliable in some cases,
-# and that in the end you just have to add a script to the root filesystem.

rootfs_overlay/eval_base64.sh

@@ -1,2 +0,0 @@
-#!/bin/sh
-eval "$(printf "$lkmc_eval" | base64 -d)"

rootfs_overlay/lkmc/conf.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+# https://github.com/cirosantilli/linux-kernel-module-cheat#find-the-kernel-config
+zcat /proc/config.gz | grep -Ei "${1:-}"

rootfs_overlay/lkmc/count.sh

@@ -1,4 +1,5 @@
 #!/bin/sh
+# Count to infinity with 1 second sleep between each increment.
 # Generate infinitely many system calls :-)
 i=0
 while true; do

rootfs_overlay/lkmc/eval_base64.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+# https://github.com/cirosantilli/linux-kernel-module-cheat#replace-init
+cd "$lkmc_home"
+eval "$(printf "$lkmc_eval" | base64 -d)"

rootfs_overlay/lkmc/loginroot.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+# https://github.com/cirosantilli/linux-kernel-module-cheat#tty
+exec /bin/login root

rootfs_overlay/lkmc/test_all.sh

@@ -20,7 +20,7 @@ for test in \
 ; do
   if ! "${test_dir}/${test}"; then
     echo "Test failed: ${test}"
-    test_fail.sh
+    ./test_fail.sh
     exit 1
   fi
 done

rootfs_overlay/loginroot.sh

@@ -1,2 +0,0 @@
-#!/bin/sh
-exec /bin/login root

rootfs_overlay/root/.profile

@@ -1,4 +0,0 @@
-# https://unix.stackexchange.com/questions/176027/ash-profile-configuration-file
-echo "hello $(pwd)/.profile"
-# Does not inherit init environment variables.
-#env

run

@@ -58,15 +58,8 @@ which is what you usually want.
             help='''\
 Replace the normal init with a minimal init that just evals the given string.
 See: https://github.com/cirosantilli/linux-kernel-module-cheat#replace-init
-'''
+chdir into lkmc_home before running the command:
-        )
+https://github.com/cirosantilli/linux-kernel-module-cheat#lkmc_home
-        self.add_argument(
-            '--kernel-cli',
-            help='''\
-Pass an extra Linux kernel command line options, and place them before
-the dash separator `-`. Only options that come before the `-`, i.e.
-"standard" options, should be passed with this option.
-Example: `./run --arch arm --kernel-cli 'init=/poweroff.out'`
 '''
         )
         self.add_argument(
@@ -75,16 +68,8 @@ Example: `./run --arch arm --kernel-cli 'init=/poweroff.out'`
 Pass a base64 encoded command line parameter that gets evalled at the end of
 the normal init.
 See: https://github.com/cirosantilli/linux-kernel-module-cheat#init-busybox
-'''
+chdir into lkmc_home before running the command:
-        )
+https://github.com/cirosantilli/linux-kernel-module-cheat#lkmc_home
-        self.add_argument(
-            '--kernel-cli-after-dash',
-            help='''\
-Pass an extra Linux kernel command line options, add a dash `-`
-separator, and place the options after the dash. Intended for custom
-options understood by our `init` scripts, most of which are prefixed
-by `lkmc_`.
-Example: `./run --kernel-cli-after-dash 'lkmc_eval="wget google.com" lkmc_lala=y'`
 '''
         )
         self.add_argument(
@@ -108,16 +93,6 @@ gem.op5 --debug-flags=Exec fs.py --cpu-type=HPI --caches
             '--gem5-readfile', default='',
             help='Set the contents of m5 readfile to this string.'
         )
-        self.add_argument(
-            '-K', '--kvm', default=False,
-            help='Use KVM. Only works if guest arch == host arch'
-        )
-        self.add_argument(
-            '--kgdb', default=False,
-        )
-        self.add_argument(
-            '--kdb', default=False,
-        )
         self.add_argument(
             '--gem5-restore', type=int,
             help='''\
@@ -125,6 +100,35 @@ Restore the nth most recently taken gem5 checkpoint according to directory
 timestamps.
 '''
         )
+        self.add_argument(
+            '--kdb', default=False,
+        )
+        self.add_argument(
+            '--kernel-cli',
+            help='''\
+Pass an extra Linux kernel command line options, and place them before
+the dash separator `-`. Only options that come before the `-`, i.e.
+"standard" options, should be passed with this option.
+Example: `./run --arch arm --kernel-cli 'init=/poweroff.out'`
+'''
+        )
+        self.add_argument(
+            '--kernel-cli-after-dash',
+            help='''\
+Pass an extra Linux kernel command line options, add a dash `-`
+separator, and place the options after the dash. Intended for custom
+options understood by our `init` scripts, most of which are prefixed
+by `lkmc_`.
+Example: `./run --kernel-cli-after-dash 'lkmc_eval="wget google.com" lkmc_lala=y'`
+'''
+        )
+        self.add_argument(
+            '--kgdb', default=False,
+        )
+        self.add_argument(
+            '-K', '--kvm', default=False,
+            help='Use KVM. Only works if guest arch == host arch'
+        )
         self.add_argument(
             '-m', '--memory', default='256M',
             help='''\
@@ -149,6 +153,15 @@ Setup a kernel init parameter that makes the emulator quit immediately after boo
             '-r', '--record', default=False,
             help='Record a QEMU run record for later replay with `-R`'
         )
+        self.add_argument(
+            '--terminal', default=False,
+            help='''\
+Output to the terminal, don't pipe to tee as the default.
+Does not save the output to a file, but allows you to use debuggers.
+Set automatically by --debug-vm, but you still need this option to debug
+gem5 Python scripts with pdb.
+'''
+        )
         self.add_argument(
             '-T', '--trace',
             help='''\
@@ -171,15 +184,6 @@ Output trace to stdout instead of a file. Only works for gem5 currently.
             default=False,
             help='''\
 Trace instructions run to stdout. Shortcut for --trace --trace-stdout.
-'''
-        )
-        self.add_argument(
-            '--terminal', default=False,
-            help='''\
-Output to the terminal, don't pipe to tee as the default.
-Does not save the output to a file, but allows you to use debuggers.
-Set automatically by --debug-vm, but you still need this option to debug
-gem5 Python scripts with pdb.
 '''
         )
         self.add_argument(
@@ -232,7 +236,7 @@ Run QEMU with VNC instead of the default SDL. Connect to it with:
             kernel_cli += ' {}'.format(self.env['kernel_cli'])
         if self.env['quit_after_boot']:
             kernel_cli += ' {}'.format(self.env['quit_init'])
-        kernel_cli_after_dash = ''
+        kernel_cli_after_dash = ' lkmc_home={}'.format(self.env['guest_lkmc_home'])
         extra_emulator_args = []
         extra_qemu_args = []
         if self.env['tmux_args'] is not None:
@@ -252,7 +256,7 @@ Run QEMU with VNC instead of the default SDL. Connect to it with:
         else:
             vnc = []
         if self.env['eval'] is not None:
-            kernel_cli += ' {}=/eval_base64.sh'.format(self.env['initarg'])
+            kernel_cli += ' {}=/lkmc/eval_base64.sh'.format(self.env['initarg'])
             kernel_cli_after_dash += ' lkmc_eval="{}"'.format(self.sh.base64_encode(self.env['eval']))
         if not self.env['graphic']:
             extra_qemu_args.extend(['-nographic', LF])

shell_helpers.py

@@ -124,12 +124,12 @@ class ShellHelpers:
         os.makedirs(destdir, exist_ok=True)
         for basename in sorted(os.listdir(srcdir)):
             src = os.path.join(srcdir, basename)
-            if os.path.isfile(src):
+            if os.path.isfile(src) or os.path.islink(src):
                 noext, ext = os.path.splitext(basename)
                 dest = os.path.join(destdir, basename)
                 if (
-                    (filter_ext is not None and ext == filter_ext) and
+                    (filter_ext is None or ext == filter_ext) and
-                    (os.path.exists(dest) and os.path.getmtime(src) > os.path.getmtime(dest))
+                    (not os.path.exists(dest) or os.path.getmtime(src) > os.path.getmtime(dest))
                 ):
                     self.cp(src, dest)
 
@@ -151,7 +151,13 @@ class ShellHelpers:
     def cp(self, src, dest, **kwargs):
         self.print_cmd(['cp', src, dest])
         if not self.dry_run:
-            shutil.copy2(src, dest)
+            if os.path.islink(src):
+                if os.path.lexists(dest):
+                    os.unlink(dest)
+                linkto = os.readlink(src)
+                os.symlink(linkto, dest)
+            else:
+                shutil.copy2(src, dest)
 
     def print_cmd(self, cmd, cwd=None, cmd_file=None, extra_env=None, extra_paths=None):
         '''

userland/c/false.c

@@ -0,0 +1,17 @@
+/* Exit with status 1.
+ *
+ * Can be uesd to test that emulators forward the exit status properly.
+ * https://github.com/cirosantilli/linux-kernel-module-cheat#gem5-syscall-emulation-exit-status
+ */
+
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    int ret;
+    if (argc == 1) {
+        ret = 1;
+    } else {
+        ret = strtoull(argv[1], NULL, 0);
+    }
+	return ret;
+}

userland/count.c

@@ -1,3 +1,5 @@
+/* Count to infinity with 1 second sleep between each increment. */
+
 #define _XOPEN_SOURCE 700
 #include <limits.h>
 #include <stdio.h>

userland/false.c

@@ -1,13 +0,0 @@
-/* Test that emulators forward the exit status properly. */
-
-#include <stdlib.h>
-
-int main(int argc, char **argv) {
-    int ret;
-    if (argc == 1) {
-        ret = 1;
-    } else {
-        ret = strtoull(argv[1], NULL, 0);
-    }
-	return ret;
-}