Add a new trace point, KTRFAC_CAPFAIL, which traces capability check

failures.  It is included in the default set for ktrace(1) and kdump(1).

4 files changed, 53 insertions, 11 deletions

diff --git a/usr.bin/kdump/kdump.c b/usr.bin/kdump/kdump.c
index 7e1c08d..8f2f4db 100644
--- a/usr.bin/kdump/kdump.c
+++ b/usr.bin/kdump/kdump.c
@@ -99,6 +99,7 @@ void ktruser(int, unsigned char *);
 void ktrsockaddr(struct sockaddr *);
 void ktrstat(struct stat *);
 void ktrstruct(char *, size_t);
+void ktrcapfail(struct ktr_cap_fail *);
 void usage(void);
 void ioctlname(unsigned long, int);
 
@@ -301,6 +302,8 @@ main(int argc, char *argv[])
 		case KTR_STRUCT:
 			ktrstruct(m, ktrlen);
 			break;
+		case KTR_CAPFAIL:
+			ktrcapfail((struct ktr_cap_fail *)m);
 		default:
 			printf("\n");
 			break;
@@ -440,6 +443,9 @@ dumpheader(struct ktr_header *kth)
 		/* FALLTHROUGH */
 	case KTR_PROCDTOR:
 		return;
+	case KTR_CAPFAIL:
+		type = "CAP ";
+		break;
 	default:
 		sprintf(unknown, "UNKNOWN(%d)", kth->ktr_type);
 		type = unknown;
@@ -488,6 +494,7 @@ ktrsyscall(struct ktr_syscall *ktr, u_int flags)
 {
 	int narg = ktr->ktr_narg;
 	register_t *ip;
+	intmax_t arg;
 
 	if ((flags != 0 && ((flags & SV_ABI_MASK) != SV_ABI_FREEBSD)) ||
 	    (ktr->ktr_code >= nsyscalls || ktr->ktr_code < 0))
@@ -978,12 +985,33 @@ ktrsyscall(struct ktr_syscall *ktr, u_int flags)
 				ip++;
 				narg--;
 				break;
-                        case SYS_cap_new:
-                                print_number(ip, narg, c);
-                                putchar(',');
-                                capname(*ip);
-                                ip++;
-                                narg--;
+			case SYS_cap_new:
+				print_number(ip, narg, c);
+				putchar(',');
+				arg = *ip;
+				ip++;
+				narg--;
+				/*
+				 * Hack: the second argument is a
+				 * cap_rights_t, which 64 bits wide, so on
+				 * 32-bit systems, it is split between two
+				 * registers.
+				 *
+				 * Since sizeof() is not evaluated by the
+				 * preprocessor, we can't use an #ifdef,
+				 * but the compiler will probably optimize
+				 * the code out anyway.
+				 */
+				if (sizeof(cap_rights_t) > sizeof(register_t)) {
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+					arg = ((intmax_t)*ip << 32) + arg;
+#else
+					arg = (arg << 32) + *ip;
+#endif
+					ip++;
+					narg--;
+				}
+				capname(arg);
 				break;
 			}
 		}
@@ -1554,6 +1582,15 @@ invalid:
 	printf("invalid record\n");
 }
 
+void
+ktrcapfail(struct ktr_cap_fail *ktr)
+{
+	printf("needed ");
+	capname((intmax_t)ktr->cap_needed);
+	printf(" held ");
+	capname((intmax_t)ktr->cap_held);
+}
+
 #if defined(__amd64__) || defined(__i386__)
 void
 linux_ktrsyscall(struct ktr_syscall *ktr)
diff --git a/usr.bin/ktrace/ktrace.1 b/usr.bin/ktrace/ktrace.1
index 9cff05b..86f23ef 100644
--- a/usr.bin/ktrace/ktrace.1
+++ b/usr.bin/ktrace/ktrace.1
@@ -28,7 +28,7 @@
 .\"	@(#)ktrace.1	8.1 (Berkeley) 6/6/93
 .\" $FreeBSD$
 .\"
-.Dd February 23, 2008
+.Dd October 10, 2011
 .Dt KTRACE 1
 .Os
 .Sh NAME
@@ -113,6 +113,8 @@ trace
 .Tn I/O
 .It Cm n
 trace namei translations
+.It Cm p
+trace capability check failures
 .It Cm s
 trace signal processing
 .It Cm t
@@ -127,7 +129,7 @@ trace
 requests
 .It Cm +
 trace the default set of trace points -
-.Cm c , i , n , s , t , u , y
+.Cm c , i , n , p , s , t , u , y
 .El
 .It Ar command
 Execute
diff --git a/usr.bin/ktrace/ktrace.h b/usr.bin/ktrace/ktrace.h
index 5e38d68..e4e4dbf 100644
--- a/usr.bin/ktrace/ktrace.h
+++ b/usr.bin/ktrace/ktrace.h
@@ -32,7 +32,7 @@
 
 #define DEF_POINTS (KTRFAC_SYSCALL | KTRFAC_SYSRET | KTRFAC_NAMEI | \
 		    KTRFAC_GENIO | KTRFAC_PSIG | KTRFAC_USER | \
-		    KTRFAC_STRUCT | KTRFAC_SYSCTL)
+		    KTRFAC_STRUCT | KTRFAC_SYSCTL | KTRFAC_CAPFAIL)
 
 #define PROC_ABI_POINTS (KTRFAC_PROCCTOR | KTRFAC_PROCDTOR)
 
diff --git a/usr.bin/ktrace/subr.c b/usr.bin/ktrace/subr.c
index 30b6b4d..5051de8 100644
--- a/usr.bin/ktrace/subr.c
+++ b/usr.bin/ktrace/subr.c
@@ -61,11 +61,14 @@ getpoints(char *s)
 		case 'c':
 			facs |= KTRFAC_SYSCALL | KTRFAC_SYSRET;
 			break;
+		case 'i':
+			facs |= KTRFAC_GENIO;
+			break;
 		case 'n':
 			facs |= KTRFAC_NAMEI;
 			break;
-		case 'i':
-			facs |= KTRFAC_GENIO;
+		case 'p':
+			facs |= KTRFAC_CAPFAIL;
 			break;
 		case 's':
 			facs |= KTRFAC_PSIG;