Make use of the new features of libdevstat to allow iostat to work on

crash dumps, and make it use sysctl for all data retrievals in the
"live" case (i.e. when not using iostat on a crash dump).
Remove setgid kmem for the iostat executable, it is not needed any
more after these changes.

Reviewed by:	ken

1 files changed, 107 insertions, 64 deletions

diff --git a/usr.sbin/iostat/iostat.c b/usr.sbin/iostat/iostat.c
index 6568824..8a8cdc8 100644
--- a/usr.sbin/iostat/iostat.c
+++ b/usr.sbin/iostat/iostat.c
@@ -103,6 +103,7 @@
 #include <sys/param.h>
 #include <sys/errno.h>
 #include <sys/dkstat.h>
+#include <sys/sysctl.h>
 
 #include <err.h>
 #include <ctype.h>
@@ -142,8 +143,9 @@ int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0;
 /* local function declarations */
 static void usage(void);
 static void phdr(int signo);
-static void devstats(int perf_select);
+static void devstats(int perf_select,double etime, int havelast);
 static void cpustats(void);
+static void getsysctl(const char *, void *, size_t);
 
 static void
 usage(void)
@@ -170,7 +172,7 @@ main(int argc, char **argv)
 	struct devstat_match *matches;
 	int num_matches = 0;
         char errbuf[_POSIX2_LINE_MAX];
-	kvm_t	 *kd;
+	kvm_t *kd = NULL;
 	int hz, stathz;
 	int headercount;
 	long generation;
@@ -179,6 +181,8 @@ main(int argc, char **argv)
 	long select_generation;
 	char **specified_devices;
 	devstat_select_mode select_mode;
+	int use_kvm, havelast = 0;
+	struct clockinfo clkinfo;
 
 	matches = NULL;
 	maxshowdevs = 3;
@@ -224,8 +228,8 @@ main(int argc, char **argv)
 				break;
 			case 't':
 				tflag++;
-				if (buildmatch(optarg, &matches, 
-					       &num_matches) != 0)
+				if (devstat_buildmatch(optarg, &matches, 
+						       &num_matches) != 0)
 					errx(1, "%s", devstat_errbuf);
 				break;
 			case 'T':
@@ -247,19 +251,32 @@ main(int argc, char **argv)
 	argc -= optind;
 	argv += optind;
 
-	/*
-	 * Discard setgid privileges if not the running kernel so that bad
-	 * guys can't print interesting stuff from kernel memory.
-	 */
-	if (nlistf != NULL || memf != NULL)
-		setgid(getgid());
+	if (nlistf == NULL && memf == NULL) {
+		use_kvm = 0;
+		getsysctl("kern.clockrate", &clkinfo, sizeof(clkinfo));
+		hz = clkinfo.hz;
+	} else {
+		use_kvm = 1;
+		kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
+		
+		if (kd == 0)
+			errx(1, "kvm_openfiles: %s", errbuf);
+		
+		if (kvm_nlist(kd, namelist) == -1)
+			errx(1, "kvm_nlist: %s", kvm_geterr(kd));
+
+		(void)nlread(X_HZ, hz);
+		(void)nlread(X_STATHZ, stathz);
+		if (stathz)
+			hz = stathz;
+	}
 
 	/*
 	 * Make sure that the userland devstat version matches the kernel
 	 * devstat version.  If not, exit and print a message informing 
 	 * the user of his mistake.
 	 */
-	if (checkversion() < 0)
+	if (devstat_checkversion(kd) < 0)
 		errx(1, "%s", devstat_errbuf);
 
 	/*
@@ -282,7 +299,7 @@ main(int argc, char **argv)
 	}
 
 	/* find out how many devices we have */
-	if ((num_devices = getnumdevs()) < 0)
+	if ((num_devices = devstat_getnumdevs(kd)) < 0)
 		err(1, "can't get number of devices");
 
 	if ((cur.dinfo = (struct devinfo *)malloc(sizeof(struct devinfo))) ==
@@ -299,7 +316,7 @@ main(int argc, char **argv)
 	 * changed here, since it almost certainly has.  We only look for
 	 * errors.
 	 */
-	if (getdevs(&cur) == -1)
+	if (devstat_getdevs(kd, &cur) == -1)
 		errx(1, "%s", devstat_errbuf);
 
 	num_devices = cur.dinfo->numdevs;
@@ -336,12 +353,12 @@ main(int argc, char **argv)
 	 * device list has changed, so we don't look for return values of 0
 	 * or 1.  If we get back -1, though, there is an error.
 	 */
-	if (selectdevs(&dev_select, &num_selected,
-		       &num_selections, &select_generation,
-		       generation, cur.dinfo->devices, num_devices,
-		       matches, num_matches,
-		       specified_devices, num_devices_specified,
-		       select_mode, maxshowdevs, hflag) == -1)
+	if (devstat_selectdevs(&dev_select, &num_selected,
+			       &num_selections, &select_generation, generation,
+			       cur.dinfo->devices, num_devices, matches,
+			       num_matches, specified_devices,
+			       num_devices_specified, select_mode, maxshowdevs,
+			       hflag) == -1)
 		errx(1, "%s", devstat_errbuf);
 
 	/*
@@ -382,19 +399,6 @@ main(int argc, char **argv)
 	if ((wflag > 0) && (cflag == 0))
 		count = -1;
 
-	kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
-
-	if (kd == 0)
-		errx(1, "kvm_openfiles: %s", errbuf);
-
-	if (kvm_nlist(kd, namelist) == -1)
-		errx(1, "kvm_nlist: %s", kvm_geterr(kd));
-
-	(void)nlread(X_HZ, hz);
-	(void)nlread(X_STATHZ, stathz);
-	if (stathz)
-		hz = stathz;
-
 	/*
 	 * If the user stops the program (control-Z) and then resumes it,
 	 * print out the header again.
@@ -410,12 +414,21 @@ main(int argc, char **argv)
 			phdr(0);
 			headercount = 20;
 		}
-		(void)kvm_read(kd, namelist[X_TK_NIN].n_value,
-		    &cur.tk_nin, sizeof(cur.tk_nin));
-		(void)kvm_read(kd, namelist[X_TK_NOUT].n_value,
-		    &cur.tk_nout, sizeof(cur.tk_nout));
-		(void)kvm_read(kd, namelist[X_CP_TIME].n_value,
-		    cur.cp_time, sizeof(cur.cp_time));
+		if (use_kvm) {
+			(void)kvm_read(kd, namelist[X_TK_NIN].n_value,
+			    &cur.tk_nin, sizeof(cur.tk_nin));
+			(void)kvm_read(kd, namelist[X_TK_NOUT].n_value,
+			    &cur.tk_nout, sizeof(cur.tk_nout));
+			(void)kvm_read(kd, namelist[X_CP_TIME].n_value,
+			    cur.cp_time, sizeof(cur.cp_time));
+		} else {
+			getsysctl("kern.tty_nin", &cur.tk_nin,
+			    sizeof(cur.tk_nin));
+			getsysctl("kern.tty_nout", &cur.tk_nout,
+			    sizeof(cur.tk_nout));
+			getsysctl("kern.cp_time", &cur.cp_time,
+			    sizeof(cur.cp_time));
+		}
 
 		tmp_dinfo = last.dinfo;
 		last.dinfo = cur.dinfo;
@@ -425,12 +438,12 @@ main(int argc, char **argv)
 
 		/*
 		 * Here what we want to do is refresh our device stats.
-		 * getdevs() returns 1 when the device list has changed.
+		 * devstat_getdevs() returns 1 when the device list has changed.
 		 * If the device list has changed, we want to go through
 		 * the selection process again, in case a device that we
 		 * were previously displaying has gone away.
 		 */
-		switch (getdevs(&cur)) {
+		switch (devstat_getdevs(kd, &cur)) {
 		case -1:
 			errx(1, "%s", devstat_errbuf);
 			break;
@@ -439,13 +452,17 @@ main(int argc, char **argv)
 
 			num_devices = cur.dinfo->numdevs;
 			generation = cur.dinfo->generation;
-			retval = selectdevs(&dev_select, &num_selected,
-					    &num_selections, &select_generation,
-					    generation, cur.dinfo->devices,
-					    num_devices, matches, num_matches,
-					    specified_devices,
-					    num_devices_specified,
-					    select_mode, maxshowdevs, hflag);
+			retval = devstat_selectdevs(&dev_select, &num_selected,
+						    &num_selections,
+						    &select_generation,
+						    generation,
+						    cur.dinfo->devices,
+						    num_devices, matches,
+						    num_matches,
+						    specified_devices,
+						    num_devices_specified,
+						    select_mode, maxshowdevs,
+						    hflag);
 			switch(retval) {
 			case -1:
 				errx(1, "%s", devstat_errbuf);
@@ -470,13 +487,17 @@ main(int argc, char **argv)
 		 */
 		if (hflag > 0) {
 			int retval;
-			retval = selectdevs(&dev_select, &num_selected,
-					    &num_selections, &select_generation,
-					    generation, cur.dinfo->devices,
-					    num_devices, matches, num_matches,
-					    specified_devices,
-					    num_devices_specified,
-					    select_mode, maxshowdevs, hflag);
+			retval = devstat_selectdevs(&dev_select, &num_selected,
+						    &num_selections,
+						    &select_generation,
+						    generation,
+						    cur.dinfo->devices,
+						    num_devices, matches,
+						    num_matches,
+						    specified_devices,
+						    num_devices_specified,
+						    select_mode, maxshowdevs,
+						    hflag);
 			switch(retval) {
 			case -1:
 				errx(1,"%s", devstat_errbuf);
@@ -505,13 +526,13 @@ main(int argc, char **argv)
 			X(cp_time);
 			etime += cur.cp_time[i];
 		}
+		etime /= (float)hz;
 		if (etime == 0.0)
 			etime = 1.0;
-		etime /= (float)hz;
 		if ((dflag == 0) || (Tflag > 0))
 			printf("%4.0f%5.0f", cur.tk_nin / etime, 
 				cur.tk_nout/etime);
-		devstats(hflag);
+		devstats(hflag, etime, havelast);
 		if ((dflag == 0) || (Cflag > 0))
 			cpustats();
 		printf("\n");
@@ -521,6 +542,7 @@ main(int argc, char **argv)
 			break;
 
 		sleep(waittime);
+		havelast = 1;
 	}
 
 	exit(0);
@@ -583,7 +605,7 @@ phdr(int signo)
 }
 
 static void
-devstats(int perf_select)
+devstats(int perf_select, double etime, int havelast)
 {
 	register int dn;
 	long double transfers_per_second;
@@ -597,7 +619,11 @@ devstats(int perf_select)
 	 * Calculate elapsed time up front, since it's the same for all
 	 * devices.
 	 */
-	busy_seconds = compute_etime(cur.busy_time, last.busy_time);
+	if (havelast)
+		busy_seconds = devstat_compute_etime(cur.busy_time,
+						     last.busy_time);
+	else
+		busy_seconds = etime;
 
 	for (dn = 0; dn < num_devices; dn++) {
 		int di;
@@ -608,12 +634,17 @@ devstats(int perf_select)
 
 		di = dev_select[dn].position;
 
-		if (compute_stats(&cur.dinfo->devices[di],
-				  &last.dinfo->devices[di], busy_seconds,
-				  &total_bytes, &total_transfers,
-				  &total_blocks, &kb_per_transfer,
-				  &transfers_per_second, &mb_per_second, 
-				  &blocks_per_second, &ms_per_transaction)!= 0)
+		if (devstat_compute_statistics(&cur.dinfo->devices[di],
+		    havelast ? &last.dinfo->devices[di] : NULL, busy_seconds,
+		    DSM_TOTAL_BYTES, &total_bytes,
+		    DSM_TOTAL_TRANSFERS, &total_transfers,
+		    DSM_TOTAL_BLOCKS, &total_blocks,
+		    DSM_KB_PER_TRANSFER, &kb_per_transfer,
+		    DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
+		    DSM_MB_PER_SECOND, &mb_per_second, 
+		    DSM_BLOCKS_PER_SECOND, &blocks_per_second,
+		    DSM_MS_PER_TRANSACTION, &ms_per_transaction,
+		    DSM_NONE) != 0)
 			errx(1, "%s", devstat_errbuf);
 
 		if (perf_select != 0) {
@@ -677,3 +708,15 @@ cpustats(void)
 		printf("%3.0f",
 		       100. * cur.cp_time[state] / (time ? time : 1));
 }
+
+static void
+getsysctl(const char *name, void *ptr, size_t len)
+{
+	size_t nlen = len;
+	
+	if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1)
+		err(1, "sysctl(%s...) failed", name);
+	if (nlen != len)
+		errx(1, "sysctl(%s...): expected %lu, got %lu", name,
+		     (unsigned long)len, (unsigned long)nlen);
+}