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Make shell script magic less prone to breakage (#643)

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The metal boot sector code was wrapped in a single-quoted
string, like so:

    MZqFpD='
    ...MZ HEADER...
    ...E_LFANEW...
    ...BIOS BOOT SECTOR...'

This might break the shell code loader if the boot sector code
contains a 0x27 (single quote) byte.  This patch wraps the
boot sector code in a here-document instead:

    MZqFpD='
    ...MZ HEADER...' <<'@'
    ...E_LFANEW...
    ...BIOS BOOT SECTOR...
    @

This is harder to break — when interpreted as a shell script,
the code can only accidentally terminate the here-document
if there is a "\n@\n" sequence inside the BIOS boot portion.
This commit is contained in:
tkchia 2022-10-02 15:45:25 +08:00 • committed by GitHub
parent 5005f2e446
commit 3e0ddf70e9
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2 changed files with 3 additions and 7 deletions
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5
ape/ape.lds
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@ -565,10 +565,7 @@ SHSTUB2(ape_loader_dd_count,
#if SupportsMetal()
HIDDEN(v_ape_realsectors =
MIN(0x70000 - IMAGE_BASE_REAL,
ROUNDUP(RVA(_edata), 4096)) / 512);
HIDDEN(v_ape_realslacksectors =
v_ape_realsectors - MIN(0x70000 - IMAGE_BASE_REAL,
ROUNDUP(RVA(_edata), 512)) / 512);
ROUNDUP(RVA(_edata), 512)) / 512);
HIDDEN(v_ape_realpages = v_ape_realsectors / (4096 / 512));
HIDDEN(v_ape_highsectors =
(ROUNDUP(RVA(_edata), 512) / 512) - v_ape_realsectors);