Introduce commandline caching in the kernel.

This fixes some nasty procfs problems for SMP, makes ps(1) run much faster,
and makes ps(1) even less dependent on /proc which will aid chroot and
jails alike.

To disable this facility and revert to previous behaviour:
        sysctl -w kern.ps_arg_cache_limit=0

For full details see the current@FreeBSD.org mail-archives.

3 files changed, 66 insertions, 0 deletions

diff --git a/lib/libc/gen/setproctitle.c b/lib/libc/gen/setproctitle.c
index a5cf234..36c21db 100644
--- a/lib/libc/gen/setproctitle.c
+++ b/lib/libc/gen/setproctitle.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 /*
  * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
@@ -74,6 +75,7 @@ setproctitle(fmt, va_alist)
 	va_list ap;
 	size_t len;
 	unsigned long ul_ps_strings;
+	int oid[4];
 
 #if defined(__STDC__)
 	va_start(ap, fmt);
@@ -103,6 +105,13 @@ setproctitle(fmt, va_alist)
 
 	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, buf, strlen(buf) + 1);
+
 	if (ps_strings == NULL) {
 		len = sizeof(ul_ps_strings);
 		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
diff --git a/lib/libkvm/kvm_proc.c b/lib/libkvm/kvm_proc.c
index 9543fee..feba974 100644
--- a/lib/libkvm/kvm_proc.c
+++ b/lib/libkvm/kvm_proc.c
@@ -33,6 +33,8 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
+ *
+ * $FreeBSD$
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
@@ -666,6 +668,52 @@ kvm_getargv(kd, kp, nchr)
 	const struct kinfo_proc *kp;
 	int nchr;
 {
+	int oid[4];
+	int i, l;
+	static int buflen;
+	static char *buf, *p;
+	static char **bufp;
+	static int argc;
+
+	if (!buflen) {
+		l = sizeof(buflen);
+		i = sysctlbyname("kern.ps_arg_cache_limit", 
+		    &buflen, &l, NULL, 0);
+		if (i == -1) {
+			buflen == 0;
+		} else {
+			buf = malloc(buflen);
+			if (buf == NULL)
+				buflen = 0;
+			argc = 32;
+			bufp = malloc(sizeof(char *) * argc);
+		}
+	}
+	if (buf != NULL) {
+		oid[0] = CTL_KERN;
+		oid[1] = KERN_PROC;
+		oid[2] = KERN_PROC_ARGS;
+		oid[3] = kp->kp_proc.p_pid;
+		l = buflen;
+		i = sysctl(oid, 4, buf, &l, 0, 0);
+		if (i == 0 && l > 0) {
+			i = 0;
+			p = buf;
+			do {
+				bufp[i++] = p;
+				p += strlen(p) + 1;
+				if (i >= argc) {
+					argc += argc;
+					bufp = realloc(bufp,
+					    sizeof(char *) * argc);
+				}
+			} while (p < buf + l);
+			bufp[i++] = 0;
+			return (bufp);
+		}
+	}
+	if (kp->kp_proc.p_flag & P_SYSTEM)
+		return (NULL);
 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
 }
 
diff --git a/lib/libutil/setproctitle.c b/lib/libutil/setproctitle.c
index a5cf234..36c21db 100644
--- a/lib/libutil/setproctitle.c
+++ b/lib/libutil/setproctitle.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 /*
  * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
@@ -74,6 +75,7 @@ setproctitle(fmt, va_alist)
 	va_list ap;
 	size_t len;
 	unsigned long ul_ps_strings;
+	int oid[4];
 
 #if defined(__STDC__)
 	va_start(ap, fmt);
@@ -103,6 +105,13 @@ setproctitle(fmt, va_alist)
 
 	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, buf, strlen(buf) + 1);
+
 	if (ps_strings == NULL) {
 		len = sizeof(ul_ps_strings);
 		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,