filemon: Trace fork via process_fork event.

This avoids needing ugly hooks and needing both a vfork and fork
handler.

MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 14 insertions, 47 deletions

diff --git a/sys/dev/filemon/filemon_wrapper.c b/sys/dev/filemon/filemon_wrapper.c
index fcf459d7d394..ea44175c8bcc 100644
--- a/sys/dev/filemon/filemon_wrapper.c
+++ b/sys/dev/filemon/filemon_wrapper.c
@@ -45,20 +45,19 @@ __FBSDID("$FreeBSD$");
 				   9-CURRENT September 10th-16th. */
 #define sys_chdir	chdir
 #define sys_execve	execve
-#define sys_fork	fork
 #define sys_link	link
 #define sys_open	open
 #define sys_rename	rename
 #define sys_stat	stat
 #define sys_symlink	symlink
 #define sys_unlink	unlink
-#define sys_vfork	vfork
 #ifdef FILEMON_HAS_LINKAT
 #define sys_linkat	linkat
 #endif
 #endif	/* __FreeBSD_version */
 
 static eventhandler_tag filemon_exit_tag;
+static eventhandler_tag filemon_fork_tag;
 
 static void
 filemon_output(struct filemon *filemon, char *msg, size_t len)
@@ -196,29 +195,6 @@ filemon_wrapper_freebsd32_execve(struct thread *td,
 #endif
 
 static int
-filemon_wrapper_fork(struct thread *td, struct fork_args *uap)
-{
-	int ret;
-	size_t len;
-	struct filemon *filemon;
-
-	if ((ret = sys_fork(td, uap)) == 0) {
-		if ((filemon = filemon_pid_check(curproc)) != NULL) {
-			len = snprintf(filemon->msgbufr,
-			    sizeof(filemon->msgbufr), "F %d %ld\n",
-			    curproc->p_pid, (long)curthread->td_retval[0]);
-
-			filemon_output(filemon, filemon->msgbufr, len);
-
-			/* Unlock the found filemon structure. */
-			filemon_filemon_unlock(filemon);
-		}
-	}
-
-	return (ret);
-}
-
-static int
 filemon_wrapper_open(struct thread *td, struct open_args *uap)
 {
 	int ret;
@@ -545,27 +521,23 @@ filemon_wrapper_unlink(struct thread *td, struct unlink_args *uap)
 	return (ret);
 }
 
-static int
-filemon_wrapper_vfork(struct thread *td, struct vfork_args *uap)
+static void
+filemon_event_process_fork(void *arg __unused, struct proc *p1,
+    struct proc *p2, int flags)
 {
-	int ret;
 	size_t len;
 	struct filemon *filemon;
 
-	if ((ret = sys_vfork(td, uap)) == 0) {
-		if ((filemon = filemon_pid_check(curproc)) != NULL) {
-			len = snprintf(filemon->msgbufr,
-			    sizeof(filemon->msgbufr), "F %d %ld\n",
-			    curproc->p_pid, (long)curthread->td_retval[0]);
+	if ((filemon = filemon_pid_check(p1)) != NULL) {
+		len = snprintf(filemon->msgbufr,
+		    sizeof(filemon->msgbufr), "F %d %d\n",
+		    p1->p_pid, p2->p_pid);
 
-			filemon_output(filemon, filemon->msgbufr, len);
+		filemon_output(filemon, filemon->msgbufr, len);
 
-			/* Unlock the found filemon structure. */
-			filemon_filemon_unlock(filemon);
-		}
+		/* Unlock the found filemon structure. */
+		filemon_filemon_unlock(filemon);
 	}
-
-	return (ret);
 }
 
 static void
@@ -579,13 +551,11 @@ filemon_wrapper_install(void)
 
 	sv_table[SYS_chdir].sy_call = (sy_call_t *) filemon_wrapper_chdir;
 	sv_table[SYS_execve].sy_call = (sy_call_t *) filemon_wrapper_execve;
-	sv_table[SYS_fork].sy_call = (sy_call_t *) filemon_wrapper_fork;
 	sv_table[SYS_open].sy_call = (sy_call_t *) filemon_wrapper_open;
 	sv_table[SYS_openat].sy_call = (sy_call_t *) filemon_wrapper_openat;
 	sv_table[SYS_rename].sy_call = (sy_call_t *) filemon_wrapper_rename;
 	sv_table[SYS_stat].sy_call = (sy_call_t *) filemon_wrapper_stat;
 	sv_table[SYS_unlink].sy_call = (sy_call_t *) filemon_wrapper_unlink;
-	sv_table[SYS_vfork].sy_call = (sy_call_t *) filemon_wrapper_vfork;
 	sv_table[SYS_link].sy_call = (sy_call_t *) filemon_wrapper_link;
 	sv_table[SYS_symlink].sy_call = (sy_call_t *) filemon_wrapper_symlink;
 #ifdef FILEMON_HAS_LINKAT
@@ -597,13 +567,11 @@ filemon_wrapper_install(void)
 
 	sv_table[FREEBSD32_SYS_chdir].sy_call = (sy_call_t *) filemon_wrapper_chdir;
 	sv_table[FREEBSD32_SYS_freebsd32_execve].sy_call = (sy_call_t *) filemon_wrapper_freebsd32_execve;
-	sv_table[FREEBSD32_SYS_fork].sy_call = (sy_call_t *) filemon_wrapper_fork;
 	sv_table[FREEBSD32_SYS_open].sy_call = (sy_call_t *) filemon_wrapper_open;
 	sv_table[FREEBSD32_SYS_openat].sy_call = (sy_call_t *) filemon_wrapper_openat;
 	sv_table[FREEBSD32_SYS_rename].sy_call = (sy_call_t *) filemon_wrapper_rename;
 	sv_table[FREEBSD32_SYS_freebsd32_stat].sy_call = (sy_call_t *) filemon_wrapper_freebsd32_stat;
 	sv_table[FREEBSD32_SYS_unlink].sy_call = (sy_call_t *) filemon_wrapper_unlink;
-	sv_table[FREEBSD32_SYS_vfork].sy_call = (sy_call_t *) filemon_wrapper_vfork;
 	sv_table[FREEBSD32_SYS_link].sy_call = (sy_call_t *) filemon_wrapper_link;
 	sv_table[FREEBSD32_SYS_symlink].sy_call = (sy_call_t *) filemon_wrapper_symlink;
 #ifdef FILEMON_HAS_LINKAT
@@ -613,6 +581,8 @@ filemon_wrapper_install(void)
 
 	filemon_exit_tag = EVENTHANDLER_REGISTER(process_exit,
 	    filemon_event_process_exit, NULL, EVENTHANDLER_PRI_LAST);
+	filemon_fork_tag = EVENTHANDLER_REGISTER(process_fork,
+	    filemon_event_process_fork, NULL, EVENTHANDLER_PRI_LAST);
 }
 
 static void
@@ -626,13 +596,11 @@ filemon_wrapper_deinstall(void)
 
 	sv_table[SYS_chdir].sy_call = (sy_call_t *)sys_chdir;
 	sv_table[SYS_execve].sy_call = (sy_call_t *)sys_execve;
-	sv_table[SYS_fork].sy_call = (sy_call_t *)sys_fork;
 	sv_table[SYS_open].sy_call = (sy_call_t *)sys_open;
 	sv_table[SYS_openat].sy_call = (sy_call_t *)sys_openat;
 	sv_table[SYS_rename].sy_call = (sy_call_t *)sys_rename;
 	sv_table[SYS_stat].sy_call = (sy_call_t *)sys_stat;
 	sv_table[SYS_unlink].sy_call = (sy_call_t *)sys_unlink;
-	sv_table[SYS_vfork].sy_call = (sy_call_t *)sys_vfork;
 	sv_table[SYS_link].sy_call = (sy_call_t *)sys_link;
 	sv_table[SYS_symlink].sy_call = (sy_call_t *)sys_symlink;
 #ifdef FILEMON_HAS_LINKAT
@@ -644,13 +612,11 @@ filemon_wrapper_deinstall(void)
 
 	sv_table[FREEBSD32_SYS_chdir].sy_call = (sy_call_t *)sys_chdir;
 	sv_table[FREEBSD32_SYS_freebsd32_execve].sy_call = (sy_call_t *)freebsd32_execve;
-	sv_table[FREEBSD32_SYS_fork].sy_call = (sy_call_t *)sys_fork;
 	sv_table[FREEBSD32_SYS_open].sy_call = (sy_call_t *)sys_open;
 	sv_table[FREEBSD32_SYS_openat].sy_call = (sy_call_t *)sys_openat;
 	sv_table[FREEBSD32_SYS_rename].sy_call = (sy_call_t *)sys_rename;
 	sv_table[FREEBSD32_SYS_freebsd32_stat].sy_call = (sy_call_t *)freebsd32_stat;
 	sv_table[FREEBSD32_SYS_unlink].sy_call = (sy_call_t *)sys_unlink;
-	sv_table[FREEBSD32_SYS_vfork].sy_call = (sy_call_t *)sys_vfork;
 	sv_table[FREEBSD32_SYS_link].sy_call = (sy_call_t *)sys_link;
 	sv_table[FREEBSD32_SYS_symlink].sy_call = (sy_call_t *)sys_symlink;
 #ifdef FILEMON_HAS_LINKAT
@@ -659,4 +625,5 @@ filemon_wrapper_deinstall(void)
 #endif	/* COMPAT_ARCH32 */
 
 	EVENTHANDLER_DEREGISTER(process_exit, filemon_exit_tag);
+	EVENTHANDLER_DEREGISTER(process_fork, filemon_fork_tag);
 }