Add commands to print kernel commandline and version (#1434)

Co-authored-by: Gulshan Singh <gsgx@google.com>

pwndbg/commands/__init__.py

@@ -499,7 +499,9 @@ def load_commands():
     import pwndbg.commands.ida
     import pwndbg.commands.ignore
     import pwndbg.commands.ipython_interactive
+    import pwndbg.commands.kcmdline
     import pwndbg.commands.kconfig
+    import pwndbg.commands.kversion
     import pwndbg.commands.leakfind
     import pwndbg.commands.memoize
     import pwndbg.commands.misc

pwndbg/commands/kcmdline.py

@@ -0,0 +1,12 @@
+import argparse
+
+import pwndbg.commands
+import pwndbg.gdblib.kernel
+
+parser = argparse.ArgumentParser(description="Return the kernel commandline (/proc/cmdline)")
+
+
+@pwndbg.commands.ArgparsedCommand(parser)
+@pwndbg.commands.OnlyWhenQemuKernel
+def kcmdline():
+    print(pwndbg.gdblib.kernel.kcmdline())

pwndbg/commands/kversion.py

@@ -0,0 +1,12 @@
+import argparse
+
+import pwndbg.commands
+import pwndbg.gdblib.kernel
+
+parser = argparse.ArgumentParser(description="Outputs the kernel version (/proc/version)")
+
+
+@pwndbg.commands.ArgparsedCommand(parser)
+@pwndbg.commands.OnlyWhenQemuKernel
+def kversion():
+    print(pwndbg.gdblib.kernel.kversion())

pwndbg/gdblib/kernel/__init__.py

@@ -21,3 +21,15 @@ def kconfig():
     if _kconfig is None:
         _kconfig = load_kconfig()
     return _kconfig
+
+
+@pwndbg.lib.memoize.reset_on_start
+def kcmdline() -> str:
+    cmdline_addr = pwndbg.gdblib.memory.pvoid(pwndbg.gdblib.symbol.address("saved_command_line"))
+    return pwndbg.gdblib.memory.string(cmdline_addr).decode("ascii")
+
+
+@pwndbg.lib.memoize.reset_on_start
+def kversion() -> str:
+    version_addr = pwndbg.gdblib.symbol.address("linux_banner")
+    return pwndbg.gdblib.memory.string(version_addr).decode("ascii").strip()