svn commit: r278479 - in head: etc sys/kern

[Rui Paulo]

Author: rpaulo
Date: Mon Feb  9 23:13:50 2015
New Revision: 278479
URL: https://svnweb.freebsd.org/changeset/base/278479

Log:
  Notify devd(8) when a process crashed.
  
  This change implements a notification (via devctl) to userland when
  the kernel produces coredumps after a process has crashed.
  devd can then run a specific command to produce a human readable crash
  report.  The command is most usually a helper that runs gdb/lldb
  commands on the file/coredump pair.  It's possible to use this
  functionality for implementing automatic generation of crash reports.
  
  devd(8) will be notified of the full path of the binary that crashed and
  the full path of the coredump file.

Modified:
  head/etc/devd.conf
  head/sys/kern/kern_sig.c

Modified: head/etc/devd.conf
==============================================================================
--- head/etc/devd.conf	Mon Feb  9 23:04:30 2015	(r278478)
+++ head/etc/devd.conf	Mon Feb  9 23:13:50 2015	(r278479)
@@ -325,4 +325,16 @@ notify 100 {
 	action "/usr/sbin/automount -c";
 };
 
+# Handle userland coredumps.
+# This commented out handler makes it possible to run an
+# automated debugging session after the core dump is generated.
+# Replace action with a proper coredump handler, but be aware that
+# it will run with elevated privileges.
+notify 10 {
+	match "system"          "kernel";
+	match "subsystem"       "signal";
+	match "type"            "coredump";
+	action "logger $comm $core";
+};
+
 */

Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c	Mon Feb  9 23:04:30 2015	(r278478)
+++ head/sys/kern/kern_sig.c	Mon Feb  9 23:13:50 2015	(r278479)
@@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/signalvar.h>
 #include <sys/vnode.h>
 #include <sys/acct.h>
+#include <sys/bus.h>
 #include <sys/capsicum.h>
 #include <sys/condvar.h>
 #include <sys/event.h>
@@ -3237,6 +3238,9 @@ coredump(struct thread *td)
 	void *rl_cookie;
 	off_t limit;
 	int compress;
+	char *data = NULL;
+	size_t len;
+	char *fullpath, *freepath = NULL;
 
 #ifdef COMPRESS_USER_CORES
 	compress = compress_user_cores;
@@ -3322,9 +3326,36 @@ close:
 	error1 = vn_close(vp, FWRITE, cred, td);
 	if (error == 0)
 		error = error1;
+	else
+		goto out;
+	/*
+	 * Notify the userland helper that a process triggered a core dump.
+	 * This allows the helper to run an automated debugging session.
+	 */
+	len = MAXPATHLEN * 2 + 5 /* comm= */ + 5 /* core= */ + 1;
+	data = malloc(len, M_TEMP, M_NOWAIT);
+	if (data == NULL)
+		goto out;
+	if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
+		goto out;
+	snprintf(data, len, "comm=%s", fullpath);
+	if (freepath != NULL) {
+		free(freepath, M_TEMP);
+		freepath = NULL;
+	}
+	if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
+		goto out;
+	snprintf(data, len, "%s core=%s", data, fullpath);
+	devctl_notify("kernel", "signal", "coredump", data);
+	free(name, M_TEMP);
+out:
 #ifdef AUDIT
 	audit_proc_coredump(td, name, error);
 #endif
+	if (freepath != NULL)
+		free(freepath, M_TEMP);
+	if (data != NULL)
+		free(data, M_TEMP);
 	free(name, M_TEMP);
 	return (error);
 }