svn commit: r336449 - in stable/11: include lib/libc/gen

[Konstantin Belousov]

Author: kib
Date: Wed Jul 18 09:54:32 2018
New Revision: 336449
URL: https://svnweb.freebsd.org/changeset/base/336449

Log:
  MFC r335939, r336088:
  Add setproctitle_fast(3) for frequent callers.

Modified:
  stable/11/include/unistd.h
  stable/11/lib/libc/gen/Symbol.map
  stable/11/lib/libc/gen/setproctitle.3
  stable/11/lib/libc/gen/setproctitle.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/include/unistd.h
==============================================================================
--- stable/11/include/unistd.h	Wed Jul 18 09:32:43 2018	(r336448)
+++ stable/11/include/unistd.h	Wed Jul 18 09:54:32 2018	(r336449)
@@ -569,6 +569,7 @@ int	 setloginclass(const char *);
 void	*setmode(const char *);
 int	 setpgrp(pid_t, pid_t);			/* obsoleted by setpgid() */
 void	 setproctitle(const char *_fmt, ...) __printf0like(1, 2);
+void	 setproctitle_fast(const char *_fmt, ...) __printf0like(1, 2);
 int	 setresgid(gid_t, gid_t, gid_t);
 int	 setresuid(uid_t, uid_t, uid_t);
 int	 setrgid(gid_t);

Modified: stable/11/lib/libc/gen/Symbol.map
==============================================================================
--- stable/11/lib/libc/gen/Symbol.map	Wed Jul 18 09:32:43 2018	(r336448)
+++ stable/11/lib/libc/gen/Symbol.map	Wed Jul 18 09:54:32 2018	(r336449)
@@ -420,6 +420,7 @@ FBSD_1.4 {
 
 FBSD_1.5 {
 	sem_clockwait_np;
+	setproctitle_fast;
 };
 
 FBSDprivate_1.0 {

Modified: stable/11/lib/libc/gen/setproctitle.3
==============================================================================
--- stable/11/lib/libc/gen/setproctitle.3	Wed Jul 18 09:32:43 2018	(r336448)
+++ stable/11/lib/libc/gen/setproctitle.3	Wed Jul 18 09:54:32 2018	(r336449)
@@ -20,7 +20,7 @@
 .\" $FreeBSD$
 .\"
 .\" The following requests are required for all man pages.
-.Dd December 16, 1995
+.Dd July 4, 2018
 .Dt SETPROCTITLE 3
 .Os
 .Sh NAME
@@ -31,12 +31,20 @@
 .In unistd.h
 .Ft void
 .Fn setproctitle "const char *fmt" "..."
+.Ft void
+.Fn setproctitle_fast "const char *fmt" "..."
 .Sh DESCRIPTION
 The
 .Fn setproctitle
 library routine sets the process title that appears on the
 .Xr ps 1
 command.
+The
+.Fn setproctitle_fast
+variant is optimized for high frequency updates, but may make the
+.Xr ps 1
+command slightly slower by not updating the kernel cache of the program
+arguments.
 .Pp
 The title is set from the executable's name, followed by the
 result of a
@@ -96,6 +104,10 @@ The
 function
 first appeared in
 .Fx 2.2 .
+The
+.Fn setproctitle_fast
+function first appeared in
+.Fx 12 .
 Other operating systems have
 similar functions.
 .Sh AUTHORS

Modified: stable/11/lib/libc/gen/setproctitle.c
==============================================================================
--- stable/11/lib/libc/gen/setproctitle.c	Wed Jul 18 09:32:43 2018	(r336448)
+++ stable/11/lib/libc/gen/setproctitle.c	Wed Jul 18 09:54:32 2018	(r336449)
@@ -55,8 +55,8 @@ struct old_ps_strings {
 
 #define SPT_BUFSIZE 2048	/* from other parts of sendmail */
 
-void
-setproctitle(const char *fmt, ...)
+static char *
+setproctitle_internal(const char *fmt, va_list ap)
 {
 	static struct ps_strings *ps_strings;
 	static char *buf = NULL;
@@ -67,27 +67,23 @@ setproctitle(const char *fmt, ...)
 	char **nargvp;
 	int nargc;
 	int i;
-	va_list ap;
 	size_t len;
 	unsigned long ul_ps_strings;
-	int oid[4];
 
 	if (buf == NULL) {
 		buf = malloc(SPT_BUFSIZE);
 		if (buf == NULL) 
-			return;
+			return (NULL);
 		nargv[0] = buf;
 	}
 
 	if (obuf == NULL ) {
 		obuf = malloc(SPT_BUFSIZE);
 		if (obuf == NULL)
-			return;
+			return (NULL);
 		*obuf = '\0';
 	}
 
-	va_start(ap, fmt);
-
 	if (fmt) {
 		buf[SPT_BUFSIZE - 1] = '\0';
 
@@ -114,22 +110,13 @@ setproctitle(const char *fmt, ...)
 		kbuf = obuf;
 	} else
 		/* Nothing to restore */
-		return;
+		return (NULL);
 
-	va_end(ap);
-
-	/* Set the title into the kernel cached command line */
-	oid[0] = CTL_KERN;
-	oid[1] = KERN_PROC;
-	oid[2] = KERN_PROC_ARGS;
-	oid[3] = getpid();
-	sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
-
 	if (ps_strings == NULL) {
 		len = sizeof(ul_ps_strings);
 		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
 		    0) == -1)
-			return;
+			return (NULL);
 		ps_strings = (struct ps_strings *)ul_ps_strings;
 	}
 
@@ -138,7 +125,7 @@ setproctitle(const char *fmt, ...)
 	 * Should not happen.
 	 */
 	if (ps_strings->ps_argvstr == NULL)
-		return;
+		return (NULL);
 
 	/* style #3 */
 	if (oargc == -1) {
@@ -167,4 +154,52 @@ setproctitle(const char *fmt, ...)
 	}
 	ps_strings->ps_nargvstr = nargc;
 	ps_strings->ps_argvstr = nargvp;
+
+	return (nargvp[0]);
+}
+
+static int fast_update = 0;
+
+void
+setproctitle_fast(const char *fmt, ...)
+{
+	va_list ap;
+	char *buf;
+	int oid[4];
+
+	va_start(ap, fmt);
+	buf = setproctitle_internal(fmt, ap);
+	va_end(ap);
+
+	if (buf && !fast_update) {
+		/* Tell the kernel to start looking in user-space */
+		oid[0] = CTL_KERN;
+		oid[1] = KERN_PROC;
+		oid[2] = KERN_PROC_ARGS;
+		oid[3] = getpid();
+		sysctl(oid, 4, 0, 0, "", 0);
+		fast_update = 1;
+	}
+}
+
+void
+setproctitle(const char *fmt, ...)
+{
+	va_list ap;
+	char *buf;
+	int oid[4];
+
+	va_start(ap, fmt);
+	buf = setproctitle_internal(fmt, ap);
+	va_end(ap);
+
+	if (buf != NULL) {
+		/* Set the title into the kernel cached command line */
+		oid[0] = CTL_KERN;
+		oid[1] = KERN_PROC;
+		oid[2] = KERN_PROC_ARGS;
+		oid[3] = getpid();
+		sysctl(oid, 4, 0, 0, buf, strlen(buf) + 1);
+		fast_update = 0;
+	}
 }