Don't do unsafe activities in the syscall handler.

MFC after:	2 weeks

1 files changed, 18 insertions, 4 deletions

diff --git a/usr.sbin/iostat/iostat.c b/usr.sbin/iostat/iostat.c
index 3611968..672c468 100644
--- a/usr.sbin/iostat/iostat.c
+++ b/usr.sbin/iostat/iostat.c
@@ -109,6 +109,7 @@
 #include <ctype.h>
 #include <fcntl.h>
 #include <kvm.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -135,10 +136,12 @@ int num_devices;
 struct device_selection *dev_select;
 int maxshowdevs;
 int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0;
+volatile sig_atomic_t phdr_flag = 0;
 
 /* local function declarations */
 static void usage(void);
 static void phdr(int signo);
+static void do_phdr();
 static void devstats(int perf_select, long double etime, int havelast);
 static void cpustats(void);
 static int readvar(kvm_t *kd, const char *name, int nlid, void *ptr,
@@ -433,6 +436,11 @@ main(int argc, char **argv)
 			}
 		 }
 
+		if (phdr_flag) {
+			phdr_flag = 0;
+			do_phdr();
+		}
+		
 		if (Cflag > 0) {
 			if (readvar(kd, "kern.cp_time", X_CP_TIME,
 			    &cur.cp_time, sizeof(cur.cp_time)) != 0) {
@@ -442,7 +450,7 @@ main(int argc, char **argv)
 		}
 
 		if (!--headercount) {
-			phdr(0);
+			do_phdr();
 			headercount = 20;
 		}
 
@@ -484,7 +492,7 @@ main(int argc, char **argv)
 				errx(1, "%s", devstat_errbuf);
 				break;
 			case 1:
-				phdr(0);
+				do_phdr();
 				headercount = 20;
 				break;
 			default:
@@ -519,7 +527,7 @@ main(int argc, char **argv)
 				errx(1,"%s", devstat_errbuf);
 				break;
 			case 1:
-				phdr(0);
+				do_phdr();
 				headercount = 20;
 				break;
 			default:
@@ -572,6 +580,13 @@ main(int argc, char **argv)
 static void
 phdr(int signo)
 {
+
+	phdr_flag = 1;	
+}
+
+static void
+do_phdr() 
+{
 	register int i;
 	int printed;
 
@@ -622,7 +637,6 @@ phdr(int signo)
 		(void)printf(" us ni sy in id\n");
 	else
 		printf("\n");
-
 }
 
 static void