truss: Add support for utrace(2).

This uses the kdump(1) utrace support code directly until a common library
is created.

This allows malloc(3) tracing with MALLOC_CONF=utrace:true and rtld tracing
with LD_UTRACE=1.  Unknown utrace(2) data is just printed as hex.

PR:		43819 [inspired by]
Reviewed by:	jhb
MFC after:	2 weeks
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D3819

4 files changed, 45 insertions, 3 deletions

diff --git a/usr.bin/truss/Makefile b/usr.bin/truss/Makefile
index 1cd0a9c..8c78196 100644
--- a/usr.bin/truss/Makefile
+++ b/usr.bin/truss/Makefile
@@ -10,6 +10,9 @@ SRCS+= ${MACHINE_ARCH}-fbsd.c
 SRCS+= ${MACHINE_CPUARCH}-fbsd.c
 .endif
 
+.PATH:	${.CURDIR:H}/kdump
+SRCS+=	utrace.c
+
 CFLAGS+= -I${.CURDIR} -I.
 CLEANFILES= syscalls.master syscalls.h ioctl.c
 
diff --git a/usr.bin/truss/syscall.h b/usr.bin/truss/syscall.h
index 3e3a1b9..a870810 100644
--- a/usr.bin/truss/syscall.h
+++ b/usr.bin/truss/syscall.h
@@ -27,6 +27,7 @@
  * Sigprocmask -- the first argument to sigprocmask().  Prints the name.
  * Kevent -- a pointer to an array of struct kevents.  Prints all elements.
  * Pathconf -- the 2nd argument of pathconf().
+ * Utrace -- utrace(2) buffer.
  *
  * In addition, the pointer types (String, Ptr) may have OUT masked in --
  * this means that the data is set on *return* from the system call -- or
@@ -43,7 +44,7 @@ enum Argtype { None = 1, Hex, Octal, Int, LongHex, Name, Ptr, Stat, Ioctl, Quad,
 	Fcntlflag, Rusage, BinString, Shutdown, Resource, Rlimit, Timeval2,
 	Pathconf, Rforkflags, ExitStatus, Waitoptions, Idtype, Procctl,
 	LinuxSockArgs, Umtxop, Atfd, Atflags, Timespec2, Accessmode, Long,
-	Sysarch, ExecArgs, ExecEnv, PipeFds, QuadHex };
+	Sysarch, ExecArgs, ExecEnv, PipeFds, QuadHex, Utrace };
 
 #define	ARG_MASK	0xff
 #define	OUT	0x100
diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c
index 540138d..d14fa86 100644
--- a/usr.bin/truss/syscalls.c
+++ b/usr.bin/truss/syscalls.c
@@ -72,6 +72,9 @@ __FBSDID("$FreeBSD$");
 #include "extern.h"
 #include "syscall.h"
 
+/* usr.bin/kdump/utrace.c */
+int kdump_print_utrace(FILE *, void *, size_t, int);
+
 /* 64-bit alignment on 32-bit platforms. */
 #if !defined(__LP64__) && defined(__powerpc__)
 #define	QUAD_ALIGN	1
@@ -342,6 +345,8 @@ static struct syscall decoded_syscalls[] = {
 		    { Atflags, 3 } } },
 	{ .name = "utimes", .ret_type = 1, .nargs = 2,
 	  .args = { { Name | IN, 0 }, { Timeval2 | IN, 1 } } },
+	{ .name = "utrace", .ret_type = 1, .nargs = 1,
+	  .args = { { Utrace, 0 } } },
 	{ .name = "wait4", .ret_type = 1, .nargs = 4,
 	  .args = { { Int, 0 }, { ExitStatus | OUT, 1 }, { Waitoptions, 2 },
 		    { Rusage | OUT, 3 } } },
@@ -860,6 +865,24 @@ print_kevent(FILE *fp, struct kevent *ke, int input)
 	fprintf(fp, ",%p,%p", (void *)ke->data, (void *)ke->udata);
 }
 
+static void
+print_utrace(FILE *fp, void *utrace_addr, size_t len)
+{
+	unsigned char *utrace_buffer;
+
+	fprintf(fp, "{ ");
+	if (kdump_print_utrace(fp, utrace_addr, len, 0)) {
+		fprintf(fp, " }");
+		return;
+	}
+
+	utrace_buffer = utrace_addr;
+	fprintf(fp, "%zu:", len);
+	while (len--)
+		fprintf(fp, " %02x", *utrace_buffer++);
+	fprintf(fp, " }");
+}
+
 /*
  * Converts a syscall argument into a string.  Said string is
  * allocated via malloc(), so needs to be free()'d.  sc is
@@ -1601,6 +1624,20 @@ print_arg(struct syscall_args *sc, unsigned long *args, long *retval,
 		fprintf(fp, "{ %ld, %ld }", retval[0], retval[1]);
 		retval[0] = 0;
 		break;
+	case Utrace: {
+		size_t len;
+		void *utrace_addr;
+
+		len = args[sc->offset + 1];
+		utrace_addr = calloc(1, len);
+		if (get_struct(pid, (void *)args[sc->offset],
+		    (void *)utrace_addr, len) != -1)
+			print_utrace(fp, utrace_addr, len);
+		else
+			fprintf(fp, "0x%lx", args[sc->offset]);
+		free(utrace_addr);
+		break;
+	}
 	default:
 		errx(1, "Invalid argument type %d\n", sc->type & ARG_MASK);
 	}
diff --git a/usr.bin/truss/truss.1 b/usr.bin/truss/truss.1
index 6a01451..7c148df 100644
--- a/usr.bin/truss/truss.1
+++ b/usr.bin/truss/truss.1
@@ -1,6 +1,6 @@
 .\" $FreeBSD$
 .\"
-.Dd May 12, 2009
+.Dd October 5, 2015
 .Dt TRUSS 1
 .Os
 .Sh NAME
@@ -95,7 +95,8 @@ options are mutually exclusive.)
 .Sh SEE ALSO
 .Xr kdump 1 ,
 .Xr ktrace 1 ,
-.Xr ptrace 2
+.Xr ptrace 2 ,
+.Xr utrace 2
 .Sh HISTORY
 The
 .Nm