dynamic: Refactor patch pattern logic #1703
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This was referenced May 11, 2023
Originally, when the user asks to only unpatch functions, uftrace would patch all other functions by default. This is counter-intuitive, especially when using the agent to unpatch at runtime. The user doesn't expect functions to be patched when they only unpatch funtions. This commit removes this behavior, and requires the user to explicitly define functions to patch. Co-authored-by: Gabriel-Andrew Pollo-Guilbert <gabrielpolloguilbert@gmail.com> Signed-off-by: Clément Guidi <cguidi@ciena.com>
Libmcount would try to unpatch by default any function that is not matched by the user patch or unpatch options. We remove this implicit behavior, so the user explicitly choses which function to unpatch. Signed-off-by: Clément Guidi <cguidi@ciena.com>
Return whether a symbol is positively or negatively matched against a pattern list, or not matched at all. Co-authored-by: Gabriel-Andrew Pollo-Guilbert <gabrielpolloguilbert@gmail.com> Signed-off-by: Clément Guidi <cguidi@ciena.com>
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This was referenced Jul 7, 2023
namhyung
approved these changes
Jul 9, 2023
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I thought it should work similar to -F and -N so patch all functions when -U is given. But I think it's different and we don't usually use -P and -U at the same time. For example, -pg and -mfentry only needs -U option since all functions are already enabled (traceable). While regular binary and -fpatchable-function-entry only needs -P.
So I think it's ok to change.
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This is the second PR in a series of patches intended to bring runtime dynamic tracing on x86_64 to uftrace.
We redefine the pattern handling logic to remove default behaviors that conflict with runtime dynamic patching. We adapt it to runtime dynamic unpatching.
Related: #1698