crashpad/tools/mac/catch_exception_tool.ad

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:doctype: manpage

= catch_exception_tool(1)

== Name

catch_exception_tool - Catch Mach exceptions and display information about them

== Synopsis

[verse]
*catch_exception_tool* *-m* 'SERVICE' ['OPTION…']

== Description

Runs a Mach exception server registered with the bootstrap server under the name
'SERVICE'. The exception server is capable of receiving exceptions for
“behavior” values of +EXCEPTION_DEFAULT+, +EXCEPTION_STATE+, and
+EXCEPTION_STATE_IDENTITY+, with or without +MACH_EXCEPTION_CODES+ set.

== Options

*-f*, *--file*='FILE'::
Information about the exception will be appended to 'FILE' instead of the
standard output stream.

*-m*, *--mach-service*='SERVICE'::
Check in with the bootstrap server under the name 'SERVICE'. This service name
may already be reserved with the bootstrap server in cases where this tool is
started by launchd(8) as a result of a message being sent to a service declared
in a job’s +MachServices+ dictionary (see launchd.plist(5)). The service name
may also be completely unknown to the system.

*-p*, *--persistent*::
Continue processing exceptions after the first one. The default mode is
one-shot, where this tool exits after processing the first exception.

*-t*, *--timeout*='TIMEOUT'::
Run for a maximum of 'TIMEOUT' seconds. Specify +0+ to request non-blocking
operation, in which the tool exits immediately if no exception is received. In
*--persistent* mode, 'TIMEOUT' applies to the overall duration that this tool
will run, not to the processing of individual exceptions. When *--timeout* is
not specified, this tool will block indefinitely while waiting for an exception.

*--help*::
Display help and exit.

*--version*::
Output version information and exit.

== Examples

Run a one-shot blocking exception server registered with the bootstrap server
under the name +svc+:
[subs="quotes"]
----
$ *catch_exception_tool --mach-service=svc --file=out &*
[1] 1233
$ *exception_port_tool --set-handler=handler=bootstrap:svc crasher*
Illegal instruction: 4
[1]+  Done    catch_exception_tool --mach-service=svc --file=out
$ *cat out*
catch_exception_tool:
behavior EXCEPTION_DEFAULT|MACH_EXCEPTION_CODES,
pid 1234, thread 56789, exception EXC_CRASH, codes[2] 0x4200001, 0,
original exception EXC_BAD_INSTRUCTION, original code[0] 1,
signal SIGILL
----

Run an on-demand exception server started by launchd(5) available via the
bootstrap server under the name +svc+:
[subs="quotes"]
----
$ *on_demand_service_tool --load --label=catch_exception \
      --mach-service=svc \
      $(which catch_exception_tool) --mach-service=svc \
      --file=/tmp/out --persistent --timeout=0*
$ *exception_port_tool --set-handler=handler=bootstrap:svc crasher*
Illegal instruction: 4
$ *on_demand_service_tool --unload --label=catch_exception*
$ *cat /tmp/out*
catch_exception_tool:
behavior EXCEPTION_DEFAULT|MACH_EXCEPTION_CODES,
pid 2468, thread 13579, exception EXC_CRASH, codes[2] 0x4200001, 0,
original exception EXC_BAD_INSTRUCTION, original code[0] 1,
signal SIGILL
----

== Exit Status

*0*::
Success. In *--persistent* mode with a *--timeout* set, it is considered
successful if at least one exception was caught when the timer expires.

*1*::
Failure, with a message printed to the standard error stream.

== See Also

exception_port_tool(1),
on_demand_service_tool(1)

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