Function HeaderForFileOffset

internal/elfexec/elfexec.go:358–377

HeaderForFileOffset attempts to identify a unique program header that includes the given file offset. It returns an error if it cannot identify a unique header.

(headers []*elf.ProgHeader, fileOffset uint64)

// includes the given file offset. It returns an error if it cannot identify a
// unique header.
func HeaderForFileOffset(headers []*elf.ProgHeader, fileOffset uint64) (*elf.ProgHeader, error) {
	var ph *elf.ProgHeader
	for _, h := range headers {
		if fileOffset >= h.Off && fileOffset < h.Off+h.Memsz {
			if ph != nil {
				// Assuming no other bugs, this can only happen if we have two or
				// more small program segments that fit on the same page, and a
				// segment other than the last one includes uninitialized data, or
				// if the debug binary used for symbolization is stripped of some
				// sections, so segment file sizes are smaller than memory sizes.
				return nil, fmt.Errorf("found second program header (%#v) that matches file offset %x, first program header is %#v. Is this a stripped binary, or does the first program segment contain uninitialized data?", *h, fileOffset, *ph)
			}
			ph = h
		}
	}
	if ph == nil {
		return nil, fmt.Errorf("no program header matches file offset %x", fileOffset)
	}
	return ph, nil
}