debug/elf: Read ELF Program headers.

NewFile has been fixed to read ELF Program headers into the structs.
Added test coverage.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4628062

src/pkg/debug/elf/file.go

@@ -93,6 +93,7 @@ func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<
 type ProgHeader struct {
 	Type   ProgType
 	Flags  ProgFlag
+	Off    uint64
 	Vaddr  uint64
 	Paddr  uint64
 	Filesz uint64
@@ -224,6 +225,8 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 	f.ABIVersion = ident[EI_ABIVERSION]
 
 	// Read ELF file header
+	var phoff int64
+	var phentsize, phnum int
 	var shoff int64
 	var shentsize, shnum, shstrndx int
 	shstrndx = -1
@@ -239,6 +242,9 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 		if v := Version(hdr.Version); v != f.Version {
 			return nil, &FormatError{0, "mismatched ELF version", v}
 		}
+		phoff = int64(hdr.Phoff)
+		phentsize = int(hdr.Phentsize)
+		phnum = int(hdr.Phnum)
 		shoff = int64(hdr.Shoff)
 		shentsize = int(hdr.Shentsize)
 		shnum = int(hdr.Shnum)
@@ -254,6 +260,9 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 		if v := Version(hdr.Version); v != f.Version {
 			return nil, &FormatError{0, "mismatched ELF version", v}
 		}
+		phoff = int64(hdr.Phoff)
+		phentsize = int(hdr.Phentsize)
+		phnum = int(hdr.Phnum)
 		shoff = int64(hdr.Shoff)
 		shentsize = int(hdr.Shentsize)
 		shnum = int(hdr.Shnum)
@@ -264,7 +273,47 @@ func NewFile(r io.ReaderAt) (*File, os.Error) {
 	}
 
 	// Read program headers
-	// TODO
+	f.Progs = make([]*Prog, phnum)
+	for i := 0; i < phnum; i++ {
+		off := phoff + int64(i)*int64(phentsize)
+		sr.Seek(off, os.SEEK_SET)
+		p := new(Prog)
+		switch f.Class {
+		case ELFCLASS32:
+			ph := new(Prog32)
+			if err := binary.Read(sr, f.ByteOrder, ph); err != nil {
+				return nil, err
+			}
+			p.ProgHeader = ProgHeader{
+				Type:   ProgType(ph.Type),
+				Flags:  ProgFlag(ph.Flags),
+				Off:    uint64(ph.Off),
+				Vaddr:  uint64(ph.Vaddr),
+				Paddr:  uint64(ph.Paddr),
+				Filesz: uint64(ph.Filesz),
+				Memsz:  uint64(ph.Memsz),
+				Align:  uint64(ph.Align),
+			}
+		case ELFCLASS64:
+			ph := new(Prog64)
+			if err := binary.Read(sr, f.ByteOrder, ph); err != nil {
+				return nil, err
+			}
+			p.ProgHeader = ProgHeader{
+				Type:   ProgType(ph.Type),
+				Flags:  ProgFlag(ph.Flags),
+				Off:    uint64(ph.Off),
+				Vaddr:  uint64(ph.Vaddr),
+				Paddr:  uint64(ph.Paddr),
+				Filesz: uint64(ph.Filesz),
+				Memsz:  uint64(ph.Memsz),
+				Align:  uint64(ph.Align),
+			}
+		}
+		p.sr = io.NewSectionReader(r, int64(p.Off), int64(p.Filesz))
+		p.ReaderAt = p.sr
+		f.Progs[i] = p
+	}
 
 	// Read section headers
 	f.Sections = make([]*Section, shnum)

src/pkg/debug/elf/file_test.go

@@ -15,6 +15,7 @@ type fileTest struct {
 	file     string
 	hdr      FileHeader
 	sections []SectionHeader
+	progs    []ProgHeader
 }
 
 var fileTests = []fileTest{
@@ -53,6 +54,13 @@ var fileTests = []fileTest{
 			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0xfb8, 0x4b0, 0x1d, 0x38, 0x4, 0x10},
 			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x1468, 0x206, 0x0, 0x0, 0x1, 0x0},
 		},
+		[]ProgHeader{
+			{PT_PHDR, PF_R + PF_X, 0x34, 0x8048034, 0x8048034, 0xa0, 0xa0, 0x4},
+			{PT_INTERP, PF_R, 0xd4, 0x80480d4, 0x80480d4, 0x15, 0x15, 0x1},
+			{PT_LOAD, PF_R + PF_X, 0x0, 0x8048000, 0x8048000, 0x5fb, 0x5fb, 0x1000},
+			{PT_LOAD, PF_R + PF_W, 0x5fc, 0x80495fc, 0x80495fc, 0xd8, 0xf8, 0x1000},
+			{PT_DYNAMIC, PF_R + PF_W, 0x60c, 0x804960c, 0x804960c, 0x98, 0x98, 0x4},
+		},
 	},
 	{
 		"testdata/gcc-amd64-linux-exec",
@@ -96,6 +104,16 @@ var fileTests = []fileTest{
 			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x19a0, 0x6f0, 0x24, 0x39, 0x8, 0x18},
 			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x2090, 0x1fc, 0x0, 0x0, 0x1, 0x0},
 		},
+		[]ProgHeader{
+			{PT_PHDR, PF_R + PF_X, 0x40, 0x400040, 0x400040, 0x1c0, 0x1c0, 0x8},
+			{PT_INTERP, PF_R, 0x200, 0x400200, 0x400200, 0x1c, 0x1c, 1},
+			{PT_LOAD, PF_R + PF_X, 0x0, 0x400000, 0x400000, 0x684, 0x684, 0x200000},
+			{PT_LOAD, PF_R + PF_W, 0x688, 0x600688, 0x600688, 0x210, 0x218, 0x200000},
+			{PT_DYNAMIC, PF_R + PF_W, 0x6b0, 0x6006b0, 0x6006b0, 0x1a0, 0x1a0, 0x8},
+			{PT_NOTE, PF_R, 0x21c, 0x40021c, 0x40021c, 0x20, 0x20, 0x4},
+			{PT_LOOS + 0x474E550, PF_R, 0x5b8, 0x4005b8, 0x4005b8, 0x24, 0x24, 0x4},
+			{PT_LOOS + 0x474E551, PF_R + PF_W, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8},
+		},
 	},
 }
 
@@ -121,11 +139,25 @@ func TestOpen(t *testing.T) {
 				t.Errorf("open %s, section %d:\n\thave %#v\n\twant %#v\n", tt.file, i, &s.SectionHeader, sh)
 			}
 		}
+		for i, p := range f.Progs {
+			if i >= len(tt.progs) {
+				break
+			}
+			ph := &tt.progs[i]
+			if !reflect.DeepEqual(&p.ProgHeader, ph) {
+				t.Errorf("open %s, program %d:\n\thave %#v\n\twant %#v\n", tt.file, i, &p.ProgHeader, ph)
+			}
+		}
 		tn := len(tt.sections)
 		fn := len(f.Sections)
 		if tn != fn {
 			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
 		}
+		tn = len(tt.progs)
+		fn = len(f.Progs)
+		if tn != fn {
+			t.Errorf("open %s: len(Progs) = %d, want %d", tt.file, fn, tn)
+		}
 	}
 }