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nixpkgs/pkgs/development/tools/profiling/systemtap/nixos-kernel-store-path.patch
Ludovic Courtès 085bf1f2f1 Add SystemTap.
svn path=/nixpkgs/trunk/; revision=21596
2010-05-04 13:32:09 +00:00

48 lines
1.6 KiB
Diff

This patch makes stap(1) know about the kernel store path on NixOS.
--- systemtap-1.2/main.cxx 2010-03-22 22:51:49.000000000 +0100
+++ systemtap-1.2/main.cxx 2010-05-04 14:56:19.000000000 +0200
@@ -528,6 +528,32 @@ getmemusage ()
return oss.str();
}
+/* Read `/proc/cmdline' and extract the store path. The assumption is that
+ `/proc/cmdline' looks like this:
+
+ BOOT_IMAGE=/nix/store/sxjd69wfcr6w8jlbcc5bc20nwjliq872-linux-2.6.32.8/bzImage systemConfig=/nix/store/kiicqkjwgfvkwrg4fp3dnhwldh7dq7is-system init=/nix/store/czgncihjwx3n58xij6i1rlnz8wv6ym4j-stage-2-init.sh splash=verbose vga=0x317
+
+ This is the case on NixOS GNU/Linux. */
+static string
+kernel_store_path (void)
+{
+ ifstream proc_cmdline ("/proc/cmdline");
+ string variable_name, store_path;
+
+ getline (proc_cmdline, variable_name, '=');
+ if (variable_name == "BOOT_IMAGE")
+ {
+ string boot_image_path;
+ size_t slash_pos;
+
+ getline (proc_cmdline, boot_image_path, ' ');
+ slash_pos = boot_image_path.find_last_of ('/');
+ store_path = boot_image_path.substr (0, slash_pos);
+ }
+
+ return store_path;
+}
+
int
main (int argc, char * const argv [])
{
@@ -541,7 +567,8 @@ main (int argc, char * const argv [])
struct utsname buf;
(void) uname (& buf);
s.kernel_release = string (buf.release);
- s.kernel_build_tree = "/lib/modules/" + s.kernel_release + "/build";
+ s.kernel_build_tree =
+ kernel_store_path () + "/lib/modules/" + s.kernel_release + "/build";
// PR4186: Copy logic from coreutils uname (uname -i) to squash
// i?86->i386. Actually, copy logic from linux top-level Makefile