Hurd Native (Debugging with GDB)

21.1.5 Commands Specific to GNU Hurd Systems

This subsection describes GDB commands specific to the GNU Hurd native debugging.

set signals set sigs

This command toggles the state of inferior signal interception by GDB. Mach exceptions, such as breakpoint traps, are not affected by this command. sigs is a shorthand alias for signals.

show signals show sigs

Show the current state of intercepting inferior’s signals.

set signal-thread set sigthread

This command tells GDB which thread is the libc signal thread. That thread is run when a signal is delivered to a running process. set sigthread is the shorthand alias of set signal-thread.

show signal-thread show sigthread

These two commands show which thread will run when the inferior is delivered a signal.

set stopped

This commands tells GDB that the inferior process is stopped, as with the SIGSTOP signal. The stopped process can be continued by delivering a signal to it.

show stopped

This command shows whether GDB thinks the debuggee is stopped.

set exceptions

Use this command to turn off trapping of exceptions in the inferior. When exception trapping is off, neither breakpoints nor single-stepping will work. To restore the default, set exception trapping on.

show exceptions

Show the current state of trapping exceptions in the inferior.

set task pause

This command toggles task suspension when GDB has control. Setting it to on takes effect immediately, and the task is suspended whenever GDB gets control. Setting it to off will take effect the next time the inferior is continued. If this option is set to off, you can use set thread default pause on or set thread pause on (see below) to pause individual threads.

show task pause

Show the current state of task suspension.

set task detach-suspend-count

This command sets the suspend count the task will be left with when GDB detaches from it.

show task detach-suspend-count

Show the suspend count the task will be left with when detaching.

set task exception-port set task excp

This command sets the task exception port to which GDB will forward exceptions. The argument should be the value of the send rights of the task. set task excp is a shorthand alias.

set noninvasive

This command switches GDB to a mode that is the least invasive as far as interfering with the inferior is concerned. This is the same as using set task pause, set exceptions, and set signals to values opposite to the defaults.

info send-rights info receive-rights info port-rights info port-sets info dead-names info ports info psets

These commands display information about, respectively, send rights, receive rights, port rights, port sets, and dead names of a task. There are also shorthand aliases: info ports for info port-rights and info psets for info port-sets.

set thread pause

This command toggles current thread suspension when GDB has control. Setting it to on takes effect immediately, and the current thread is suspended whenever GDB gets control. Setting it to off will take effect the next time the inferior is continued. Normally, this command has no effect, since when GDB has control, the whole task is suspended. However, if you used set task pause off (see above), this command comes in handy to suspend only the current thread.

show thread pause

This command shows the state of current thread suspension.

set thread run

This command sets whether the current thread is allowed to run.

show thread run

Show whether the current thread is allowed to run.

set thread detach-suspend-count

This command sets the suspend count GDB will leave on a thread when detaching. This number is relative to the suspend count found by GDB when it notices the thread; use set thread takeover-suspend-count to force it to an absolute value.

show thread detach-suspend-count

Show the suspend count GDB will leave on the thread when detaching.

set thread exception-port set thread excp

Set the thread exception port to which to forward exceptions. This overrides the port set by set task exception-port (see above). set thread excp is the shorthand alias.

set thread takeover-suspend-count

Normally, GDB’s thread suspend counts are relative to the value GDB finds when it notices each thread. This command changes the suspend counts to be absolute instead.

set thread default show thread default

Each of the above set thread commands has a set thread default counterpart (e.g., set thread default pause, set thread default exception-port, etc.). The thread default variety of commands sets the default thread properties for all threads; you can then change the properties of individual threads with the non-default commands.