Add a simple utility to send control messages

The svrctl utility allows you to send control messages to VFS or PM.
This way you can retrieve runtime information or alter behavior.

commands/Makefile

@@ -26,7 +26,7 @@ SUBDIR=	add_route arp ash at awk \
 	reboot remsync rev rget rlogin \
 	rotate rsh rshd sed service setup shar acksize \
 	sleep slip sort spell split srccrc \
-	stty sum svclog swifi sync synctree sysenv \
+	stty sum svclog svrctl swifi sync synctree sysenv \
 	syslogd tail tar tcpd tcpdp tcpstat tee telnet \
 	telnetd term termcap tget time touch tr \
 	truncate tsort tty udpstat umount uname unexpand \

commands/svrctl/Makefile

@@ -0,0 +1,5 @@
+PROG=	svrctl
+BINDIR=	/usr/bin
+MAN=
+
+.include <bsd.prog.mk>

commands/svrctl/svrctl.c

@@ -0,0 +1,118 @@
+#include <sys/svrctl.h>
+#include <sys/types.h>
+#include <ctype.h>
+#include <lib.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static void usage(void);
+
+#define VFS			"vfs"
+#define PM			"pm"
+#define SET			"set"
+#define GET			"get"
+
+static char *bin_name;
+
+int main (int argc, char *argv[])
+{
+  int r, param;
+  endpoint_t proc_e = NONE;
+  struct sysgetenv sysgetenv;
+  message m;
+  char *to_whom, *operation, *what, *value;
+  unsigned i;
+
+  bin_name = argv[0];
+  if (argc < 4 || argc > 5) usage();
+  if (geteuid() != 0) {
+	fprintf(stderr, "You have to be root to run this utility\n");
+	exit(EXIT_FAILURE);
+  }
+
+  /* Make some parameters lower case to ease comparing */
+  to_whom = argv[1];
+  operation = argv[2];
+  what = argv[3];
+  for (i = 0; i < strlen(to_whom); ++i)   to_whom[i] = tolower(to_whom[i]);
+  for (i = 0; i < strlen(operation); ++i) operation[i] = tolower(operation[i]);
+  for (i = 0; i < strlen(what); ++i)      what[i] = tolower(what[i]);
+
+  if (!strncmp(to_whom, VFS, strlen(VFS)+1)) proc_e = VFS_PROC_NR;
+  else if (!strncmp(to_whom, PM, strlen(PM)+1)) proc_e = PM_PROC_NR;
+  else usage();
+
+  sysgetenv.key = what;
+  sysgetenv.keylen = strlen(what) + 1;
+
+  if (!strncmp(operation, SET, strlen(SET)+1)) {
+	if (argc != 5) usage();
+	value = argv[4];
+	sysgetenv.val = value;
+	sysgetenv.vallen = strlen(value) + 1;
+
+	if (proc_e == VFS_PROC_NR)
+		param = VFSSETPARAM;
+	else if (proc_e == PM_PROC_NR)
+		param = PMSETPARAM;
+	else
+		usage();
+
+	m.m2_i1 = param;
+	m.m2_p1 = (char *) &sysgetenv;
+	r = _syscall(proc_e, SVRCTL, &m);
+	if (r != 0) {
+		if (errno == ESRCH)
+			fprintf(stderr, "invalid parameter: %s\n", what);
+		else if (errno == EINVAL)
+			fprintf(stderr, "invalid value: %s\n", value);
+		else
+			perror("");
+		exit(EXIT_FAILURE);
+	}
+	return(EXIT_SUCCESS);
+  } else if (!strncmp(operation, GET, strlen(GET)+1)) {
+	char get_param_buffer[4096];
+
+	memset(get_param_buffer, '\0', sizeof(get_param_buffer));
+	sysgetenv.val = get_param_buffer;
+	sysgetenv.vallen = sizeof(get_param_buffer) - 1;
+
+	if (proc_e == VFS_PROC_NR)
+		param = VFSGETPARAM;
+	else if (proc_e == PM_PROC_NR)
+		param = PMGETPARAM;
+	else
+		usage();
+
+	m.m2_i1 = param;
+	m.m2_p1 = (char *) &sysgetenv;
+	r = _syscall(proc_e, SVRCTL, &m);
+	if (r != 0) {
+		if (errno == ESRCH)
+			fprintf(stderr, "invalid parameter: %s\n", what);
+		else
+			perror("");
+		return(EXIT_FAILURE);
+	} else {
+		if (sysgetenv.vallen > 0) {
+			get_param_buffer[sysgetenv.vallen] = '\0';
+			printf("%s\n", get_param_buffer);
+		}
+	}
+	return(EXIT_SUCCESS);
+  } else
+	usage();
+
+  return(EXIT_FAILURE);
+}
+
+static void usage()
+{
+  fprintf(stderr, "Usage:\n");
+  fprintf(stderr, "  %s <vfs|pm> set <request> <value>\n", bin_name);
+  fprintf(stderr, "  %s <vfs|pm> get <request>\n", bin_name);
+  exit(EXIT_FAILURE);
+}

man/man1/Makefile

@@ -16,7 +16,7 @@ MAN=	ash.1 at.1 banner.1 basename.1 \
 	profile.1 ps.1 pwd.1 rcp.1 readall.1 recwave.1 \
 	ref.1 remsync.1 rget.1 rlogin.1 rsh.1 rz.1 \
 	shar.1 acksize.1 sleep.1 sort.1   spell.1 \
-	split.1 stty.1 sum.1 svc.1 \
+	split.1 stty.1 sum.1 svc.1 svrctl.1 \
 	synctree.1 sysenv.1 sz.1 tail.1 tee.1 telnet.1 template.1 \
 	term.1 termcap.1 tget.1 time.1 tr.1 true.1 \
 	truncate.1 tsort.1 tty.1 umount.1 uname.1 unexpand.1 \

man/man1/svrctl.1

@@ -0,0 +1,65 @@
+.Dd $April 5, 2012$
+.Dt SVRCTL 1
+.Os
+.Sh NAME
+.Nm svrctl
+.Nd send servers control messages
+.Sh SYNOPSIS
+.Nm
+.Ar <vfs|pm> Ar get Ar <request>
+.Nm
+.Ar <vfs|pm> Ar set Ar <request> Ar <value>
+.Sh DESCRIPTION
+The
+.Nm
+utility allows to override the values of variables inside VFS or PM or to
+retrieve the values of variables. The variables that are allowed to be
+overridden are hard coded in the servers.
+.Sh EXAMPLES
+To retrieve how many threads are currently actively carrying out work in VFS:
+.Bd -literal -offset indent
+svrctl vfs get active_threads
+.Ed
+.Pp
+To generate a stack trace of all threads in VFS:
+.Bd -literal -offset indent
+svrctl vfs get print_traces
+.Ed
+.Pp
+To set verbosity level of VFS (allowed values range from 0 to 4)
+.Bd -literal -offset indent
+svrctl vfs set verbose 1
+.Ed
+.Pp
+To retrieve boot monitor parameters (note that these are also available through
+.Xr sysenv 1
+) such as
+.Va rootdevname
+,
+.Va memory
+,
+.Va hz
+, and if set,
+.Va bootopts
+,
+.Va cttyline
+,
+.Va cttybaud
+:
+.Bd -literal -offset indent
+svrctl pm get rootdevname
+svrctl pm get memory
+svrctl pm get hz
+svrctl pm get bootopts
+svrctl pm get cttyline
+svrctl pm get cttybaud
+.Ed
+.Sh EXIT STATUS
+In case
+.Nm
+is not properly invoked or the provided
+.Va request
+is not valid 1 is returned, otherwise 0.
+.Sh AUTHORS
+.An Thomas Veerman
+.Aq thomas@minix3.org