btfdump: Allow to dump from /sys/kernel/btf/vmlinux #16
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Support dumping BTF not only from ELF files, but also from raw BTF information (which starts directly with BTF magic number) like the one peresent in /sys/kernel/btf/vmlinux. This way, btfdump can be used for generating the vmlinux.h for the given kernel. Also, don't use mmap, since it doesn't work on sysfs.
| // Read the magic number first. | ||
| let mut buffer = [0u8; 2]; | ||
| file.read_exact(&mut buffer)?; | ||
| let magic_number: u16 = u16::from_le_bytes(buffer); |
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this should take into account host endianness, no?
| } else { | ||
| // Otherwise, assume it's an object file and parse BTF from | ||
| // the `.BTF` section. | ||
| let file = object::File::parse(contents.as_slice())?; |
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can you please keep mmap way for ELF case? ELF file can potentially be very big, there is no need to allocate so much memory for the buffer
| let magic_number: u16 = u16::from_le_bytes(buffer); | ||
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| // And then the full file content. | ||
| let mut contents = Vec::with_capacity(usize::try_from(file.metadata()?.len())?); |
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can you add BTF::load_file() API which would detect raw vs ELF internally and just return BTF? And then use that at least for Stat command below as well. Both dump and state are frequently used (by me, at least), so would be good to keep them both in sync in terms of what they support.
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@vadorovsky do you plan on posting an update for this? |
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@anakryiko Yes, sorry, I will address your comments later today. |
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(still working on that - I will try to wrap during during holidays) |
Support dumping BTF not only from ELF files, but also from raw BTF information (which starts directly with BTF magic number) like the one peresent in /sys/kernel/btf/vmlinux.
This way, btfdump can be used for generating the vmlinux.h for the given kernel.
Also, don't use mmap, since it doesn't work on sysfs.