- Introduce '-S' option which allows to match system processes (pgrep only).

- Rename IS_KERNPROC() macro to PSKIP() and extend its functionality.
  Now it'll skip calling process and system processes when -S is not given.
  As a side effect it fixes '-n' option. Before it was always matching
  calling process (because of missing 'if (kp->ki_pid == mypid)' check)
  and after that, calling process was ignored.
- When '-l' option is given and there are no arguments, use p_comm as an
  arguments list (this is helpful for kernel threads matching).

Reviewed by:	gad
MFC after:	3 days

2 files changed, 21 insertions, 21 deletions

diff --git a/usr.bin/pkill/pkill.1 b/usr.bin/pkill/pkill.1
index b870458..7a272b2 100644
--- a/usr.bin/pkill/pkill.1
+++ b/usr.bin/pkill/pkill.1
@@ -44,7 +44,7 @@
 .Nd find or signal processes by name
 .Sh SYNOPSIS
 .Nm pgrep
-.Op Fl filnvx
+.Op Fl Sfilnvx
 .Op Fl F Ar pidfile
 .Op Fl G Ar gid
 .Op Fl M Ar core
@@ -105,6 +105,8 @@ which is the kernel image the system has booted from.
 Restrict matches to processes with a parent process ID in the
 comma-separated list
 .Ar ppid .
+.It Fl S
+Search also in system processes (kernel threads).
 .It Fl U Ar uid
 Restrict matches to processes with a real user ID in the comma-separated
 list
diff --git a/usr.bin/pkill/pkill.c b/usr.bin/pkill/pkill.c
index 07eb1a2..132de3e 100644
--- a/usr.bin/pkill/pkill.c
+++ b/usr.bin/pkill/pkill.c
@@ -72,8 +72,9 @@ __FBSDID("$FreeBSD$");
 #define	MIN_PID	5
 #define	MAX_PID	99999
 
-/* Check for system-processes which should always be ignored. */
-#define	IS_KERNPROC(kp)	((kp)->ki_flag & P_KTHREAD)
+/* Ignore system-processes (if '-S' flag is not specified) and myself. */
+#define	PSKIP(kp)	((kp)->ki_pid == mypid ||			\
+			 (!kthreads && ((kp)->ki_flag & P_KTHREAD) != 0))
 
 enum listtype {
 	LT_GENERIC,
@@ -102,6 +103,7 @@ int	inverse;
 int	longfmt;
 int	matchargs;
 int	fullmatch;
+int	kthreads;
 int	cflags = REG_EXTENDED;
 kvm_t	*kd;
 pid_t	mypid;
@@ -175,7 +177,7 @@ main(int argc, char **argv)
 	pidfromfile = -1;
 	execf = coref = _PATH_DEVNULL;
 
-	while ((ch = getopt(argc, argv, "DF:G:M:N:P:U:d:fg:ij:lns:t:u:vx")) != -1)
+	while ((ch = getopt(argc, argv, "DF:G:M:N:P:SU:d:fg:ij:lns:t:u:vx")) != -1)
 		switch (ch) {
 		case 'D':
 			debug_opt++;
@@ -198,6 +200,11 @@ main(int argc, char **argv)
 			makelist(&ppidlist, LT_GENERIC, optarg);
 			criteria = 1;
 			break;
+		case 'S':
+			if (!pgrep)
+				usage();
+			kthreads = 1;
+			break;
 		case 'U':
 			makelist(&ruidlist, LT_USER, optarg);
 			criteria = 1;
@@ -295,17 +302,15 @@ main(int argc, char **argv)
 		}
 
 		for (i = 0, kp = plist; i < nproc; i++, kp++) {
-			if (IS_KERNPROC(kp) != 0) {
+			if (PSKIP(kp)) {
 				if (debug_opt > 0)
 				    fprintf(stderr, "* Skipped %5d %3d %s\n",
 					kp->ki_pid, kp->ki_uid, kp->ki_comm);
 				continue;
 			}
 
-			if (matchargs) {
-				if ((pargv = kvm_getargv(kd, kp, 0)) == NULL)
-					continue;
-
+			if (matchargs &&
+			    (pargv = kvm_getargv(kd, kp, 0)) != NULL) {
 				jsz = 0;
 				while (jsz < sizeof(buf) && *pargv != NULL) {
 					jsz += snprintf(buf + jsz,
@@ -314,7 +319,6 @@ main(int argc, char **argv)
 					    pargv[0]);
 					pargv++;
 				}
-
 				mstr = buf;
 			} else
 				mstr = kp->ki_comm;
@@ -345,7 +349,7 @@ main(int argc, char **argv)
 	}
 
 	for (i = 0, kp = plist; i < nproc; i++, kp++) {
-		if (IS_KERNPROC(kp) != 0)
+		if (PSKIP(kp))
 			continue;
 
 		if (pidfromfile >= 0 && kp->ki_pid != pidfromfile) {
@@ -457,17 +461,13 @@ main(int argc, char **argv)
 	 * Take the appropriate action for each matched process, if any.
 	 */
 	for (i = 0, rv = 0, kp = plist; i < nproc; i++, kp++) {
-		if (kp->ki_pid == mypid)
+		if (PSKIP(kp))
 			continue;
 		if (selected[i]) {
 			if (inverse)
 				continue;
 		} else if (!inverse)
 			continue;
-
-		if (IS_KERNPROC(kp) != 0)
-			continue;
-
 		rv = 1;
 		(*action)(kp);
 	}
@@ -481,7 +481,7 @@ usage(void)
 	const char *ustr;
 
 	if (pgrep)
-		ustr = "[-filnvx] [-d delim]";
+		ustr = "[-Sfilnvx] [-d delim]";
 	else
 		ustr = "[-signal] [-finvx]";
 
@@ -507,10 +507,8 @@ grepact(struct kinfo_proc *kp)
 {
 	char **argv;
 
-	if (longfmt && matchargs) {
-		if ((argv = kvm_getargv(kd, kp, 0)) == NULL)
-			return;
-
+	if (longfmt && matchargs &&
+	    (argv = kvm_getargv(kd, kp, 0)) != NULL) {
 		printf("%d ", (int)kp->ki_pid);
 		for (; *argv != NULL; argv++) {
 			printf("%s", *argv);