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repair ELF fixup on native-library installation

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The fixup is not allowed to changed the virtual
address of a SHT_PROGBITS section, so a expanded
".dynstr" section might have to be moved to a
virtual address after everything else.
This commit is contained in:
Matthew Flatt 2014-10-11 14:08:26 -06:00
parent 2f351b626b
commit 608ac636eb
1 changed files with 54 additions and 15 deletions
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69
racket/collects/compiler/private/elf.rkt
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@ -11,7 +11,8 @@
(define LITTLEEND 1)
(define BIGEND 2)
(define SECTION-ALIGN 16) ; conservative?
(define SECTION-TABLE-ALIGN 16) ; conservative enough?
(define SECTION-ALIGN 16) ; conservative enough?
(define SHT_PROGBITS 1)
(define SHT_NOBITS 8)
@ -279,23 +280,35 @@
;; New state:
section-name ; #f or name of new section
get-data ; get data for new section (if any)
;; expansions must be after section headers, must
;; Expansions must be after section headers, must
;; not be at the version beginning of a section,
;; and beware of extending sections that need
;; ".dynamic" support (such as the ".dynstr" section,
;; which is currently supported here):
;; which is currently supported here); each
;; expansion element has the form
;; (list <offset> <expand-amt>)
expansions ; list of (list position delta)
;; If `vaddr-moves` is not supplied, then
;; virtual-address adjustments are derived from
;; `expansions` based on the way it overlaps with
;; section offets. If those adjustments would move
;; any SHT_PROGBITS sections, though, then the
;; expanded section(s) must be moved, instead,
;; as described by `vaddr-moves`. Each element
;; has the form
;; (list <old-vaddr> <length> <new-vaddr>)
#:vaddr-moves [vaddr-moves #f]
finish)
(define num-new-sections (if section-name 1 0))
(let ([new-sec-pos (+ (* num-new-sections (elf-sh-offset elf))
(* (elf-sh-esize elf) (elf-sh-ecount elf)))]
[new-sec-delta (round-up (* num-new-sections (elf-sh-esize elf))
SECTION-ALIGN)]
SECTION-TABLE-ALIGN)]
[new-str-pos (+ (section-offset str-section)
(section-size str-section))]
[new-str-delta (if section-name
(round-up (add1 (bytes-length section-name))
SECTION-ALIGN)
SECTION-TABLE-ALIGN)
0)]
[class (elf-class elf)]
[format (elf-format elf)])
@ -316,13 +329,25 @@
(if get-data
(get-data (+ total-size new-str-delta new-sec-delta))
(values #"" 0 0))])
(define vm-expansions (filter
values
(for/list ([expansion (in-list expansions)])
(define s (find-section-by-offset (car expansion) sections))
(and s (list (+ (section-addr s)
(- (car expansion) (section-offset s)))
(cadr expansion))))))
(define vm-expansions
(if vaddr-moves
(apply
append
(for/list ([move (in-list vaddr-moves)])
(list
;; shift at start of region:
(list (car move)
(- (caddr move) (car move)))
;; unshift at end of region:
(list (+ (car move) (cadr move))
(- (car move) (caddr move))))))
(filter
values
(for/list ([expansion (in-list expansions)])
(define s (find-section-by-offset (car expansion) sections))
(and s (list (+ (section-addr s)
(- (car expansion) (section-offset s)))
(cadr expansion)))))))
(call-with-output-file*
dest-file
#:exists 'truncate
@ -410,7 +435,12 @@
(file-position out (adjust (+ (elf-sh-offset elf)
(* i (elf-sh-esize elf))
(at-class 14 16))))
(write-addr (vm-adjust addr))
(define new-addr (vm-adjust addr))
(unless (or (= new-addr addr)
(not (= SHT_PROGBITS (section-type s))))
(error 'expand-elf "cannot move SHT_PROGBITS section"))
(write-addr new-addr)
(write-off (adjust offset))
(unless (= SHT_NOBITS (section-type s))
@ -586,13 +616,22 @@
;; New pos is just before last nul byte, to make sure it's
;; within the section:
(sub1 (+ (section-offset dynstr) (section-size dynstr))))
(define new-vm-addr
(for/fold ([addr (section-addr dynstr)]) ([s (in-list sections)])
(max addr (+ (section-addr s) (section-size s)))))
(expand-elf in dest-file
elf sections programs str-section strs (file-size src-file)
;; No new section:
#f #f
;; Add rpath at end of dynstrs:
;; Add rpath at end of dynstrs, use virtual address
;; past all allocated:
(list
(list new-str-pos (+ (bytes-length rpath) 1)))
(list new-str-pos
(round-up (+ (bytes-length rpath) 1) SECTION-ALIGN)))
#:vaddr-moves (list
(list (section-addr dynstr)
(section-size dynstr)
(round-up new-vm-addr SECTION-ALIGN)))
(lambda (out adjust adjust*)
;; Write new dynstr:
(file-position out (adjust* new-str-pos))