Annotation of src/usr.bin/ktrace/ltrace.1, Revision 1.8
1.8 ! jmc 1: .\" $OpenBSD: ltrace.1,v 1.7 2015/09/07 15:38:45 guenther Exp $
1.1 miod 2: .\"
3: .\" Copyright (c) 2013 Miodrag Vallat.
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44: .\" from: @(#)ktrace.1 8.1 (Berkeley) 6/6/93
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1.8 ! jmc 46: .Dd $Mdocdate: September 7 2015 $
1.1 miod 47: .Dt LTRACE 1
48: .Os
49: .Sh NAME
50: .Nm ltrace
51: .Nd shared library function call tracer
52: .Sh SYNOPSIS
53: .Nm ltrace
54: .Op Fl ai
55: .Op Fl f Ar trfile
1.5 miod 56: .Op Fl t Ar trstr
1.1 miod 57: .Op Fl u Ar trspec
58: .Ar command
59: .Sh DESCRIPTION
60: .Nm ltrace
61: enables shared library function calls issued by the specified processes
62: to be traced using the
63: .Xr utrace 2
64: user tracing facility.
65: By default, call trace data is logged to the file
66: .Pa ktrace.out ,
67: unless overridden by the
68: .Fl f
69: option.
70: Each function call is traced as a pair of
71: .Dv KTRFAC_USER
72: entries;
73: the first entry contains the shared library containing the symbol being
74: called, and the second entry contains the symbol name.
75: .Pp
76: Once tracing is enabled on a process, trace data will be logged until
77: either the process exits or the trace point is cleared with
78: .Xr ktrace 1 .
79: A traced process can generate enormous amounts of log data quickly;
80: it is strongly suggested that users memorize how to disable tracing before
81: attempting to trace a process.
82: The following command is sufficient to disable tracing on all user owned
1.6 jmc 83: processes and, if executed by root, all processes:
1.1 miod 84: .Pp
85: .Dl $ ktrace -C
86: .Pp
87: The trace file is not human-readable; use
88: .Xr kdump 1
89: to decode it.
90: .Pp
91: The options are as follows:
92: .Bl -tag -width 9n
93: .It Fl a
94: Append to the trace file instead of recreating it.
95: .It Fl f Ar trfile
96: Log trace records to
97: .Ar trfile
98: instead of
99: .Pa ktrace.out .
100: .It Fl i
101: Inherit; pass the trace flags to all future children of the designated
102: processes.
1.5 miod 103: .It Fl t Ar trstr
104: The string argument represents the kernel trace points, one per letter.
105: The default flags are
106: .Cm c ,
107: .Cm e ,
108: .Cm i ,
109: .Cm n ,
110: .Cm s ,
111: .Cm t ,
112: and
113: .Cm u .
114: The following table equates the letters with the tracepoints:
115: .Pp
116: .Bl -tag -width flag -offset indent -compact
117: .It Cm c
118: trace system calls
119: .It Cm e
120: trace emulation changes
121: .It Cm i
122: trace I/O
123: .It Cm n
124: trace namei translations
125: .It Cm s
126: trace signal processing
127: .It Cm t
128: trace various structures
129: .It Cm u
130: trace user data coming from
131: .Xr utrace 2
1.8 ! jmc 132: .El
1.5 miod 133: .It Cm +
134: trace the default points
1.1 miod 135: .It Fl u Ar trspec
136: Restrict the trace to a list of shared objects and/or function names, as
137: specified by the
138: .Ar trspec
139: argument.
140: The trace specification is a comma-separated list of library names,
141: followed by a colon
1.2 jmc 142: .Pq :\& ,
143: and a comma-separated list of function names.
1.1 miod 144: Each list can be empty.
1.2 jmc 145: Each list member may end with a star
1.1 miod 146: .Pq *
147: to only match the beginning of a name.
1.4 jmc 148: An exclamation mark at the beginning of a list turns it into a rejection list,
1.1 miod 149: causing all unmatched names to be traced.
150: Library names are compared without their version number and
151: .Sq .so
152: suffix.
1.2 jmc 153: .It Ar command
154: Execute
155: .Ar command
156: with the specified trace flags.
1.1 miod 157: .El
158: .Sh FILES
1.2 jmc 159: .Bl -tag -width ktrace.outXXX -compact
1.1 miod 160: .It Pa ktrace.out
1.2 jmc 161: Default
162: .Nm
163: dump file.
1.1 miod 164: .El
165: .Sh EXAMPLES
166: Trace all shared library function calls from
167: .Xr wc 1
168: reading the message of the day:
169: .Dl $ ltrace wc -lh /etc/motd
170: .Pp
171: Trace only the shared library function calls in
172: .Pa libutil.so :
173: .Dl $ ltrace -u libutil wc -lh /etc/motd
174: .Pp
175: Trace all the shared library function calls but those in
176: .Pa libc.so :
177: .Dl $ ltrace -u \(dq!libc\(dq wc -lh /etc/motd
178: .Pp
1.2 jmc 179: Trace all the shared library function calls with names starting
1.3 jmc 180: .Qq fmt :
1.1 miod 181: .Dl $ ltrace -u \(dq:fmt*\(dq wc -lh /etc/motd
1.5 miod 182: .Pp
183: Trace all shared library function calls, as well as all system calls:
184: .Dl $ ltrace -t cu wc -lh /etc/motd
1.1 miod 185: .Sh SEE ALSO
186: .Xr kdump 1 ,
187: .Xr ktrace 1 ,
188: .Xr ktrace 2 ,
189: .Xr utrace 2
1.5 miod 190: .Sh HISTORY
191: The
192: .Nm ltrace
193: command appeared in
194: .Ox 5.4 .