Add support for displaying thread IDs to truss(1).

- Consolidate duplicate code for printing the metadata at the start of
  each line into a shared function.
- Add an -H option which will log the thread ID of the relevant thread
  for each event.

While here, remove some extraneous calls to clock_gettime() in
print_syscall() and print_syscall_ret().  The caller of print_syscall_ret()
always updates the current thread's "after" time before it is called.

Reviewed by:	kib
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D5363

1 files changed, 9 insertions, 3 deletions

diff --git a/usr.bin/truss/truss.1 b/usr.bin/truss/truss.1
index fb02cb4e75ab..0246fa933928 100644
--- a/usr.bin/truss/truss.1
+++ b/usr.bin/truss/truss.1
@@ -1,6 +1,6 @@
 .\" $FreeBSD$
 .\"
-.Dd October 9, 2015
+.Dd February 23, 2016
 .Dt TRUSS 1
 .Os
 .Sh NAME
@@ -8,12 +8,12 @@
 .Nd trace system calls
 .Sh SYNOPSIS
 .Nm
-.Op Fl facedDS
+.Op Fl facedDHS
 .Op Fl o Ar file
 .Op Fl s Ar strsize
 .Fl p Ar pid
 .Nm
-.Op Fl facedDS
+.Op Fl facedDHS
 .Op Fl o Ar file
 .Op Fl s Ar strsize
 .Ar command Op Ar args
@@ -32,6 +32,10 @@ Trace descendants of the original traced process created by
 .Xr fork 2 ,
 .Xr vfork 2 ,
 etc.
+To distinguish events between processes,
+the process ID
+.Pq PID
+of the process is included in the output of each event.
 .It Fl a
 Show the argument strings that are passed in each
 .Xr execve 2
@@ -52,6 +56,8 @@ since the trace was started.
 .It Fl D
 Include timestamps in the output showing the time elapsed
 since the last recorded event.
+.It Fl H
+Include the thread ID of in the output of each event.
 .It Fl S
 Do not display information about signals received by the process.
 (Normally,