Return an empty file range for SHT_NOBITS sections #253
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ELF sections with type SHT_NOBITS only exist in memory, and don't contain any data in the ELF file itself. Fixes m4b#252.
src/elf/section_header.rs
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| // Sections with type SHT_NOBITS have no data in the file itself, | ||
| // they only exist in memory. | ||
| if self.sh_type == SHT_NOBITS { | ||
| self.sh_offset as usize..self.sh_offset as usize |
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is returning a 0 range going to cause issues? ideally we'd return an Option<Range<usize>> i think, but that would be breaking change. Might be worth it though?
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ok i don't think this should be self.sh_offset..self.sh_offset; if sh_offset is non-zero you can get e.g., 10..10 or whatever, that is an empty range but will cause a panic if it's larger than buffer, i.e., this panics:
let foo = [1, 2, 3];
let x = &foo[10..10];So i think it's better to return 0..0 ? or Option.
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Oh, I didn't expect the empty range to panic when it's out of bounds.
I think 0..0would be confusing as well, if someone looks at the start field of the range to decide where the data in the file starts.
An Option would be the solution, in my opinion.
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Ok let's make it option, it's the right thing to do :) this will be a breaking change so unless you are in urgent need of a release, i may wait a bit to roll up other potential changes, or make other breaking changes
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I don't need it urgently, manually checking the section type is an easy workaround.
Some sections don't occupy any space in the file, for these sections we now return None instead of a range.
| pub fn file_range(&self) -> Range<usize> { | ||
| self.sh_offset as usize..(self.sh_offset as usize).saturating_add(self.sh_size as usize) | ||
| /// Returns this section header's file offset range, | ||
| /// if the section occupies space in fhe file. |
|
thanks for this PR ! :) |
ELF sections with type SHT_NOBITS only exist in memory, and
don't contain any data in the ELF file itself. The range
returned by
file_range()should be empty for such sections.The previously returned range was wrong, and overlapped
the file range of the next section.
Fixes #252.