.fi
.sp
..
+.\" Macro IX is not defined in the groff macros
+.if \n(.g \{\
+. de IX
+..
+.\}
.TH STRACE 1 "2010-03-30"
.SH NAME
strace \- trace system calls and signals
.SH SYNOPSIS
.B strace
-[\fB-CdffhiqrtttTvVxxy\fR]
+[\fB-CdffhikqrtttTvVxxy\fR]
[\fB-I\fIn\fR]
[\fB-b\fIexecve\fR]
[\fB-e\fIexpr\fR]...
Errors (typically a return value of \-1) have the errno symbol
and error string appended.
.CW
-open("/foo/bar", O_RDONLY) = -1 ENOENT (No such file or directory)
+open("/foo/bar", O_RDONLY) = \-1 ENOENT (No such file or directory)
.CE
Signals are printed as signal symbol and decoded siginfo structure.
An excerpt from stracing and interrupting the command "sleep 666" is:
always be dereferenced. For example, retrying the "ls \-l" example
with a non-existent file produces the following line:
.CW
-lstat("/foo/bar", 0xb004) = -1 ENOENT (No such file or directory)
+lstat("/foo/bar", 0xb004) = \-1 ENOENT (No such file or directory)
.CE
In this case the porch light is on but nobody is home.
.LP
.BR vfork (2)
and
.BR clone (2)
-system calls. Note that
+system calls. Note that
.B \-p
.I PID
.B \-f
.B \-i
Print the instruction pointer at the time of the system call.
.TP
+.B \-k
+Print the execution stack trace of the traced processes after each system call (experimental).
+.TP
.B \-q
Suppress messages about attaching, detaching etc. This happens
automatically when output is redirected to a file and the command
of seconds since the epoch.
.TP
.B \-T
-Show the time spent in system calls. This records the time
+Show the time spent in system calls. This records the time
difference between the beginning and the end of each system call.
.TP
+.B \-w
+Summarise the time difference between the beginning and end of
+each system call. The default is to summarise the system time.
+.TP
.B \-v
Print unabbreviated versions of environment, stat, termios, etc.
calls. These structures are very common in calls and so the default
.B \-y
Print paths associated with file descriptor arguments.
.TP
+.B \-yy
+Print ip:port pairs associated with socket file descriptors.
+.TP
.BI "\-a " column
Align return values in a specific column (default column 40).
.TP
If specified syscall is reached, detach from traced process.
Currently, only
.I execve
-syscall is supported. This option is useful if you want to trace
+syscall is supported. This option is useful if you want to trace
multi-threaded process and therefore require -f, but don't want
to trace its (potentially very complex) children.
.TP
or how to trace them. The format of the expression is:
.RS 15
.IP
-[\fIqualifier\fB=\fR][\fB!\fR]\fIvalue1\fR[\fB,\fIvalue2\fR]...
+[\,\fIqualifier\/\fB=\fR][\fB!\fR]\,\fIvalue1\/\fR[\fB,\,\fIvalue2\/\fR]...
.RE
.IP
where
expansion even inside quoted arguments. If so, you must escape
the exclamation point with a backslash.
.TP
-\fB\-e\ trace\fR=\fIset\fR
+\fB\-e\ trace\fR=\,\fIset\fR
Trace only the specified set of system calls. The
.B \-c
option is useful for determining which system calls might be useful
.BR "\-e\ trace" = memory
Trace all memory mapping related system calls.
.TP
-\fB\-e\ abbrev\fR=\fIset\fR
+\fB\-e\ abbrev\fR=\,\fIset\fR
Abbreviate the output from printing each member of large structures.
The default is
.BR abbrev = all .
option has the effect of
.BR abbrev = none .
.TP
-\fB\-e\ verbose\fR=\fIset\fR
+\fB\-e\ verbose\fR=\,\fIset\fR
Dereference structures for the specified set of system calls. The
default is
.BR verbose = all .
.TP
-\fB\-e\ raw\fR=\fIset\fR
+\fB\-e\ raw\fR=\,\fIset\fR
Print raw, undecoded arguments for the specified set of system calls.
This option has the effect of causing all arguments to be printed
in hexadecimal. This is mostly useful if you don't trust the
decoding or you need to know the actual numeric value of an
argument.
.TP
-\fB\-e\ signal\fR=\fIset\fR
+\fB\-e\ signal\fR=\,\fIset\fR
Trace only the specified subset of signals. The default is
.BR signal = all .
For example,
.BR signal "=!" io )
causes SIGIO signals not to be traced.
.TP
-\fB\-e\ read\fR=\fIset\fR
+\fB\-e\ read\fR=\,\fIset\fR
Perform a full hexadecimal and ASCII dump of all the data read from
file descriptors listed in the specified set. For example, to see
all input activity on file descriptors
and
.I 5
use
-\fB\-e\ read\fR=\fI3\fR,\fI5\fR.
+\fB\-e\ read\fR=\,\fI3\fR,\fI5\fR.
Note that this is independent from the normal tracing of the
.BR read (2)
system call which is controlled by the option
.BR -e "\ " trace = read .
.TP
-\fB\-e\ write\fR=\fIset\fR
+\fB\-e\ write\fR=\,\fIset\fR
Perform a full hexadecimal and ASCII dump of all the data written to
file descriptors listed in the specified set. For example, to see
all output activity on file descriptors
and
.I 5
use
-\fB\-e\ write\fR=\fI3\fR,\fI5\fR.
+\fB\-e\ write\fR=\,\fI3\fR,\,\fI5\fR.
Note that this is independent from the normal tracing of the
.BR write (2)
system call which is controlled by the option
Unless this option is used setuid and setgid programs are executed
without effective privileges.
.TP
-\fB\-E\ \fIvar\fR=\fIval\fR
+\fB\-E\ \fIvar\fR=\,\fIval\fR
Run command with
.IR var = val
in its list of environment variables.
On some platforms a process that is attached to with the
.B \-p
option may observe a spurious EINTR return from the current
-system call that is not restartable. (Ideally, all system calls
+system call that is not restartable. (Ideally, all system calls
should be restarted on strace attach, making the attach invisible
to the traced process, but a few system calls aren't.
Arguably, every instance of such behavior is a kernel bug.)
.B \-i
option is weakly supported.
.SH HISTORY
-.B strace
The original
.B strace
was written by Paul Kranenburg
projects / strace / blobdiff