jdx/mise · error · eyre::Report

unexpected ELF e_phentsize {e_phentsize}

Error message

unexpected ELF e_phentsize {e_phentsize}

What it means

While pouring a Linux bottle, the ELF rewriter (elf::patch) walks the program header table and requires e_phentsize to equal 56 (sizeof Elf64_Phdr for 64-bit). Any other value means the file is corrupt, truncated, or produced by nonstandard tooling, and the parser refuses to continue rather than compute bogus offsets.

Source

Thrown at src/system/packages/brew/elf.rs:114

    b[off..off + 8].copy_from_slice(&v.to_le_bytes());
}

#[derive(Clone, Copy)]
struct Phdr {
    p_type: u32,
    p_offset: u64,
    p_vaddr: u64,
    p_filesz: u64,
    p_memsz: u64,
    p_align: u64,
}

fn read_phdrs(content: &[u8]) -> Result<Vec<Phdr>> {
    let e_phoff = rd_u64(content, 32)? as usize;
    let e_phentsize = rd_u16(content, 54)? as usize;
    let e_phnum = rd_u16(content, 56)? as usize;
    if e_phentsize != PHDR_SIZE {
        bail!("unexpected ELF e_phentsize {e_phentsize}");
    }
    if e_phnum >= 0xffff {
        bail!("ELF uses PN_XNUM program header counts");
    }
    let mut phdrs = Vec::with_capacity(e_phnum);
    for i in 0..e_phnum {
        let off = e_phoff + i * PHDR_SIZE;
        phdrs.push(Phdr {
            p_type: rd_u32(content, off)?,
            p_offset: rd_u64(content, off + 8)?,
            p_vaddr: rd_u64(content, off + 16)?,
            p_filesz: rd_u64(content, off + 32)?,
            p_memsz: rd_u64(content, off + 40)?,
            p_align: rd_u64(content, off + 48)?,
        });
    }
    Ok(phdrs)
}

View on GitHub (pinned to 9dcfcaa0dc)

Solutions

1. Clear the cached bottle and re-download it, verifying the sha256 matches the API manifest
2. Inspect the file with readelf -h <file> — if e_phentsize is not 56 outside this tool, the binary itself is broken
3. If readelf shows a valid file, report the binary to the project — the parser may need extending for this producer

// Cheap pre-check before relocation: sane ELF64 header fields.
fn elf_phentsize_ok(content: &[u8]) -> bool {
    content.len() >= 56
        && content[..4] == [0x7f, b'E', b'L', b'F']
        && content[4] == 2 && content[5] == 1
        && u16::from_le_bytes(content[54..56].try_into().unwrap()) == 56
}

fn is_wellformed_elf64(content: &[u8]) -> bool {
    content.len() >= 64 && content[..4] == [0x7f, b'E', b'L', b'F']
        && content[4] == 2 && content[5] == 1
        && u16::from_le_bytes(content[54..56].try_into().unwrap()) == 56
        && u16::from_le_bytes(content[56..58].try_into().unwrap()) < 0xffff
}

// Treat per-file patch failures as fatal for that formula but report the path:
match elf::patch(&mut content, &opts, &path) {
    Ok(changed) => { /* ... */ }
    Err(err) => return Err(err.wrap_err_with(|| format!("relocating {}", path.display()))),
}

When it happens

Trigger: elf::patch -> read_phdrs after the 64-bit LE checks pass: rd_u16(content, 54) != PHDR_SIZE (56). Triggered by a truncated/corrupted bottle download, a file with forged ELF magic, or an ELF built by a linker emitting nonstandard program header entry sizes.

Common situations: Broken bottle cache after an interrupted download; upstream bottle built with experimental tooling; disk corruption; a text file accidentally named as the binary.

Related errors

• ELF uses PN_XNUM program header counts
• cannot relocate {}: rpath must grow but the dynamic string t
• malformed Mach-O in {}
• malformed load command table in {}
• malformed load command in {}

AI-assisted analysis of jdx/mise@9dcfcaa0dc (2026-08-17). Data as JSON: /api/errors/e28cad677a9768c8. Report an issue: GitHub.