Fixed PR13055 by getting procfs probes working on 3.1 kernels.

* runtime/procfs.c (_stp_rmdir_proc_module): Fix problem where
  '/proc/systemtap' wasn't getting removed correctly.
  (_stp_mkdir_proc_module): Add support for kernels where neither
  path_lookup() or kern_path_parent() are exported (such as the 3.1
  kernels).
* buildrun.cxx (compile_pass): Convert compile test for kern_path_parent()
  to an export test.  Add exports tests for path_lookup() and
  vfs_path_lookup().
* runtime/autoconf-kern-path-parent.c: Removed.

diff --git a/buildrun.cxx b/buildrun.cxx
index 60c7741290df97942abdebe7eb85d62d0d7566f9..b0dc070214782073230198cf483c306c8abb7770 100644 (file)
--- a/buildrun.cxx
+++ b/buildrun.cxx
@@ -249,8 +249,9 @@ compile_pass (systemtap_session& s)
                  "STAPCONF_PERF_COUNTER_CONTEXT", NULL);
   output_autoconf(s, o, "perf_probe_handler_nmi.c",
                  "STAPCONF_PERF_HANDLER_NMI", NULL);
-  output_autoconf(s, o, "autoconf-kern-path-parent.c",
-                 "STAPCONF_KERN_PATH_PARENT", NULL);
+  output_exportconf(s, o, "path_lookup", "STAPCONF_PATH_LOOKUP");
+  output_exportconf(s, o, "kern_path_parent", "STAPCONF_KERN_PATH_PARENT");
+  output_exportconf(s, o, "vfs_path_lookup", "STAPCONF_VFS_PATH_LOOKUP");
 
   // used by tapset/timestamp_monotonic.stp
   output_exportconf(s, o, "cpu_clock", "STAPCONF_CPU_CLOCK");

diff --git a/runtime/autoconf-kern-path-parent.c b/runtime/autoconf-kern-path-parent.c
deleted file mode 100644 (file)
index fad64d6..0000000
--- a/runtime/autoconf-kern-path-parent.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <linux/namei.h>
-
-/* kernel commit c9c6cac0c2bdbda */
-int ____autoconf_func(const char *name)
-{
-    return kern_path_parent(name, NULL);
-}

diff --git a/runtime/procfs.c b/runtime/procfs.c
index 3587f62d06d1596003e55ba42c073ea2bd1e1f9c..13712c46799aeecd722017d7339f159e23d4e725 100644 (file)
--- a/runtime/procfs.c
+++ b/runtime/procfs.c
@@ -12,6 +12,15 @@
 #ifndef _STP_PROCFS_C_
 #define _STP_PROCFS_C_
 
+#if (!defined(STAPCONF_PATH_LOOKUP) && !defined(STAPCONF_KERN_PATH_PARENT) \
+     && !defined(STAPCONF_VFS_PATH_LOOKUP))
+#error "Either path_lookup(), kern_path_parent(), or vfs_path_lookup() must be exported by the kernel."
+#endif
+
+#ifdef STAPCONF_VFS_PATH_LOOKUP
+#include <linux/pid_namespace.h>
+#endif
+
 /* The maximum number of files AND directories that can be opened.
  * It would be great if the translator would emit this based on the actual
  * number of needed files.
@@ -20,7 +29,7 @@
 #define STP_MAX_PROCFS_FILES 16
 #endif
 
-#ifndef STAPCONF_KERN_PATH_PARENT
+#if defined(STAPCONF_PATH_LOOKUP) && !defined(STAPCONF_KERN_PATH_PARENT)
 #define kern_path_parent(name, nameidata) \
        path_lookup(name, LOOKUP_PARENT, nameidata)
 #endif
@@ -67,7 +76,7 @@ static void _stp_rmdir_proc_module(void)
                 * though it will not show up in directory
                 * listings. */
 
-               if (atomic_read(&_stp_proc_stap->count) == 0) {
+               if (atomic_read(&_stp_proc_stap->count) == LAST_ENTRY_COUNT) {
                        remove_proc_entry("systemtap", NULL);
                        _stp_proc_stap = NULL;
                }
@@ -83,6 +92,7 @@ static void _stp_rmdir_proc_module(void)
 static int _stp_mkdir_proc_module(void)
 {      
         if (_stp_proc_root == NULL) {
+#if defined(STAPCONF_PATH_LOOKUP) || defined(STAPCONF_KERN_PATH_PARENT)
                struct nameidata nd;
 
                if (!_stp_lock_transport_dir()) {
@@ -119,7 +129,43 @@ static int _stp_mkdir_proc_module(void)
                        path_release (&nd);
                        #endif
                }
-               
+#else  /* STAPCONF_VFS_PATH_LOOKUP */
+               struct path path;
+               struct vfsmount *mnt;
+               int rc;
+
+               if (!_stp_lock_transport_dir()) {
+                       errk("Unable to lock transport directory.\n");
+                       goto done;
+               }
+
+               /* See if '/proc/systemtap' exists. */
+               if (! init_pid_ns.proc_mnt) {
+                       _stp_unlock_transport_dir();
+                       goto done;
+               }
+               mnt = init_pid_ns.proc_mnt;
+               rc = vfs_path_lookup(mnt->mnt_root, mnt, "systemtap", 0,
+                                    &path);
+
+               /* If '/proc/systemtap' exists, update
+                * _stp_proc_stap.  Otherwise create the directory. */
+               if (rc == 0) {
+                        _stp_proc_stap = PDE(path.dentry->d_inode);
+                        path_put (&path);
+               }
+               else if (rc == -ENOENT) {
+                       _stp_proc_stap = proc_mkdir ("systemtap", NULL);
+                       if (_stp_proc_stap == NULL) {
+                               _stp_unlock_transport_dir();
+                               goto done;
+                       }
+               }
+#endif /* STAPCONF_VFS_PATH_LOOKUP */
+
+               /* Now that we've found '/proc/systemtap', create the
+                * module specific directory
+                * '/proc/systemtap/MODULE_NAME'. */
                _stp_proc_root = proc_mkdir(THIS_MODULE->name, _stp_proc_stap);
 #ifdef STAPCONF_PROCFS_OWNER
                if (_stp_proc_root != NULL)