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loader.c uses AT_FLAGS to communicate literally #1168

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loader.c uses AT_FLAGS to communicate literally #1168

wants to merge 5 commits into from

Commits on May 6, 2024

  1. loader.c uses AT_FLAGS to communicate literally 

    Now the `ape - prog args...` form communicates to the loaded binary that
argv[0] is preserved. This is done via either editing the previous flags
passed in auxv, or adding a new AT_FLAGS value at the end if one was not
found.

I decided to always insert an AT_FLAGS entry, although another option is
to only insert one if literally is true. This would change the value for
`n` to `... + 2 * (!flags && literally) + ...` and add another branch to
the if statement. I guessed that the extra branch was not worth saving 2
words on the stack sometimes.
    @mrdomino
    mrdomino committed May 6, 2024
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  2. Add TODO in test 

    We should be measuring the AT_FLAGS of the child process, since it may
be true even if it is false for the parent process.
    @mrdomino
    mrdomino committed May 6, 2024
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  3. Zero out end-of-auxv 

    I haven’t actually thought extremely carefully about exactly which value
gets zeroed by the previously-mentioned loop, but it varies by one word,
so it’s wrong half the time.
    @mrdomino
    mrdomino committed May 6, 2024
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  4. Set flags correctly

    @mrdomino
    mrdomino committed May 6, 2024
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  5. Only take the first flags

    @mrdomino
    mrdomino committed May 6, 2024
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