From d24a36cc4caf51c88082c9b17201b6088b9bfc86 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Thu, 5 Oct 2017 10:06:30 -0400 Subject: [PATCH] debug/elf: make safe for Go 1.4 compilers We're going to start building cmd/cgo as part of the bootstrap, and with it debug/elf, so the copy here needs to work with Go 1.4. It does except for the use of the new io.SeekStart etc constants, so remove that use. Change-Id: Ib7fcf46e1e9060f96d2bacaaf349c9b0df347550 Reviewed-on: https://go-review.googlesource.com/68337 Run-TryBot: Russ Cox Reviewed-by: David Crawshaw --- src/debug/elf/file.go | 19 +++++++++++++++---- src/debug/elf/reader.go | 6 +++--- 2 files changed, 18 insertions(+), 7 deletions(-) diff --git a/src/debug/elf/file.go b/src/debug/elf/file.go index 8eeab65df8..95c0606f80 100644 --- a/src/debug/elf/file.go +++ b/src/debug/elf/file.go @@ -17,6 +17,17 @@ import ( "strings" ) +// seekStart, seekCurrent, seekEnd are copies of +// io.SeekStart, io.SeekCurrent, and io.SeekEnd. +// We can't use the ones from package io because +// we want this code to build with Go 1.4 during +// cmd/dist bootstrap. +const ( + seekStart int = 0 + seekCurrent int = 1 + seekEnd int = 2 +) + // TODO: error reporting detail /* @@ -269,7 +280,7 @@ func NewFile(r io.ReaderAt) (*File, error) { switch f.Class { case ELFCLASS32: hdr := new(Header32) - sr.Seek(0, io.SeekStart) + sr.Seek(0, seekStart) if err := binary.Read(sr, f.ByteOrder, hdr); err != nil { return nil, err } @@ -288,7 +299,7 @@ func NewFile(r io.ReaderAt) (*File, error) { shstrndx = int(hdr.Shstrndx) case ELFCLASS64: hdr := new(Header64) - sr.Seek(0, io.SeekStart) + sr.Seek(0, seekStart) if err := binary.Read(sr, f.ByteOrder, hdr); err != nil { return nil, err } @@ -315,7 +326,7 @@ func NewFile(r io.ReaderAt) (*File, error) { f.Progs = make([]*Prog, phnum) for i := 0; i < phnum; i++ { off := phoff + int64(i)*int64(phentsize) - sr.Seek(off, io.SeekStart) + sr.Seek(off, seekStart) p := new(Prog) switch f.Class { case ELFCLASS32: @@ -359,7 +370,7 @@ func NewFile(r io.ReaderAt) (*File, error) { names := make([]uint32, shnum) for i := 0; i < shnum; i++ { off := shoff + int64(i)*int64(shentsize) - sr.Seek(off, io.SeekStart) + sr.Seek(off, seekStart) s := new(Section) switch f.Class { case ELFCLASS32: diff --git a/src/debug/elf/reader.go b/src/debug/elf/reader.go index eab437318d..a45843619e 100644 --- a/src/debug/elf/reader.go +++ b/src/debug/elf/reader.go @@ -63,11 +63,11 @@ func (r *readSeekerFromReader) Read(p []byte) (n int, err error) { func (r *readSeekerFromReader) Seek(offset int64, whence int) (int64, error) { var newOffset int64 switch whence { - case io.SeekStart: + case seekStart: newOffset = offset - case io.SeekCurrent: + case seekCurrent: newOffset = r.offset + offset - case io.SeekEnd: + case seekEnd: newOffset = r.size + offset default: return 0, os.ErrInvalid -- 2.48.1