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freebsd/usr.bin/gcore/gcore.1
Attilio Rao 2e7ecbfbc8 Change gcore in order to get rid of the procfs accesses and use FreeBSD's
specific sysctls and ptrace interfaces.
This change switches a bit gcore POLA that is summarized here:
- now gcore can recognize threads within the process and handle dumps
  on thread-scope
- the process to be analyzed will be stopped during its gcore run
- gcore may not work with processes which are actively being analyzed
  by gdb or truss
- the ptrace interface may cause syscalls to return EINTR, thus
  interferring with signals handling within the process

Side note: <janitor task> the interface can be further lifted in order to
get rid of the very last procfs interfaces remnants and made more
suitable for copying with sysctl/ptrace interface </janitor task>.

Obtained from:	Sandvine Incorporated
Reviewed by:	emaste, rwatson
Sponsored by:	Sandvine Incorporated
MFC:		1 month
2009-11-25 15:23:14 +00:00

100 lines
3.1 KiB
Groff

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.\" @(#)gcore.1 8.2 (Berkeley) 4/18/94
.\" $FreeBSD$
.\"
.Dd November 18, 2009
.Dt GCORE 1
.Os
.Sh NAME
.Nm gcore
.Nd get core images of running process
.Sh SYNOPSIS
.Nm
.Op Fl s
.Op Fl c Ar core
.Op Ar executable
.Ar pid
.Sh DESCRIPTION
The
.Nm
utility creates a core image of the specified process,
suitable for use with
.Xr gdb 1 .
By default, the core is written to the file
.Dq Pa core.<pid> .
The process identifier,
.Ar pid ,
must be given on the command line.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl c
Write the core file to the specified file instead of
.Dq Pa core.<pid> .
.It Fl s
Stop the process while gathering the core image, and resume it
when done.
This guarantees that the resulting core dump will
be in a consistent state.
The process is resumed even if it was
already stopped.
The same effect can be achieved manually with
.Xr kill 1 .
.El
.Sh FILES
.Bl -tag -width /var/log/messages -compact
.It Pa core.<pid>
the core image
.El
.Sh HISTORY
A
.Nm
utility appeared in
.Bx 4.2 .
.Sh BUGS
Because of the
.Xr ptrace 2
usage
.Nm
may not work with processes which are actively investigated with
.Xr truss 1
or
.Xr gdb 1 .
Additionally, interruptable sleeps may exit with EINTR.
.Pp
The
.Nm
utility is not compatible with the original
.Bx 4.2
version.