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d547e711a8
Currently it's not possible to use gdbstub for debugging linux-user code that runs in a forked child, which is normally done using the `set follow-fork-mode child` GDB command. Purely on the protocol level, the missing piece is the fork-events feature. However, a deeper problem is supporting $Hg switching between different processes - right now it can do only threads. Implementing this for the general case would be quite complicated, but, fortunately, for the follow-fork-mode case there are a few factors that greatly simplify things: fork() happens in the exclusive section, there are only two processes involved, and before one of them is resumed, the second one is detached. This makes it possible to implement a simplified scheme: the parent and the child share the gdbserver socket, it's used only by one of them at any given time, which is coordinated through a separate socketpair. The processes can read from the gdbserver socket only one byte at a time, which is not great for performance, but, fortunately, the follow-fork-mode handling involves only a few messages. Advertise the fork-events support, and remember whether GDB has it as well. Implement the state machine that is initialized on fork(), decides the current owner of the gdbserver socket, and is terminated when one of the two processes is detached. The logic for the parent and the child is the same, only the initial state is different. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-Id: <20240219141628.246823-12-iii@linux.ibm.com> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20240305121005.3528075-13-alex.bennee@linaro.org> |
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| .. | ||
| gdbstub.c | ||
| internals.h | ||
| meson.build | ||
| syscalls.c | ||
| system.c | ||
| trace-events | ||
| trace.h | ||
| user-target.c | ||
| user.c | ||