opensnoop.bt(8)

NAME
opensnoop.bt - Trace open(),openat(),openat2() syscalls. Uses bpftrace/eBPF.

SYNOPSIS
opensnoop.bt -- [--depth=<N>] [--errname]

DESCRIPTION
opensnoop traces the open(),openat(),openat2() syscall, showing which processes are attempting to open which files. This can be useful for determining the location of config and log files, or for troubleshooting applications that are failing, specially on startup. This works by tracing the open(),openat(),openat2() syscall tracepoint. Since this uses BPF, only the root user can use this tool.

OPTIONS

--depth=<N>
    Used to set the maximum supported path depth, default is 35.

--errname
    Show error message instead of errno.

REQUIREMENTS
CONFIG_BPF and bcc.

EXAMPLES

Trace all open(),openat(),openat2() syscalls:
    # opensnoop.bt

FIELDS
PID Process ID

COMM
    Process name

FD  File descriptor (if success), or -1 (if failed)

ERR Error number (see the system's errno.h)

PATH
    Open path

OVERHEAD
This traces the open tracepoint and prints output for each event. As the rate of this is generally expected to be low (< 1000/s), the overhead is also expected to be negligible. If you have an application that is calling a high rate of open()s, then test and understand overhead before use.

SOURCE
This is from bpftrace.

    https://github.com/bpftrace/bpftrace

Also look in the bpftrace distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool. This is a bpftrace version of the bcc tool of the same name. The bcc tool may provide more options and customizations.

    https://github.com/iovisor/bcc

OS
Linux

STABILITY
Unstable - in development.

AUTHORS
Brendan Gregg, Rong Tao <rongtao@cestc.cn>

SEE ALSO
statsnoop.bt(8), execsnoop.bt(8)