podman

1
//go:build !go1.16
2
// +build !go1.16
3

4
/*
5
 * Copyright 2021 ByteDance Inc.
6
 *
7
 * Licensed under the Apache License, Version 2.0 (the "License");
8
 * you may not use this file except in compliance with the License.
9
 * You may obtain a copy of the License at
10
 *
11
 *     http://www.apache.org/licenses/LICENSE-2.0
12
 *
13
 * Unless required by applicable law or agreed to in writing, software
14
 * distributed under the License is distributed on an "AS IS" BASIS,
15
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16
 * See the License for the specific language governing permissions and
17
 * limitations under the License.
18
 */
19

20
package loader
21

22
import (
23
   `os`
24
   `unsafe`
25
   `sort`
26

27
   `github.com/bytedance/sonic/internal/rt`
28
)
29

30
const (
31
    _Magic uint32 = 0xfffffffa
32
)
33

34
type pcHeader struct {
35
    magic          uint32  // 0xFFFFFFF0
36
    pad1, pad2     uint8   // 0,0
37
    minLC          uint8   // min instruction size
38
    ptrSize        uint8   // size of a ptr in bytes
39
    nfunc          int     // number of functions in the module
40
    nfiles         uint    // number of entries in the file tab
41
    funcnameOffset uintptr // offset to the funcnametab variable from pcHeader
42
    cuOffset       uintptr // offset to the cutab variable from pcHeader
43
    filetabOffset  uintptr // offset to the filetab variable from pcHeader
44
    pctabOffset    uintptr // offset to the pctab variable from pcHeader
45
    pclnOffset     uintptr // offset to the pclntab variable from pcHeader
46
}
47

48
type moduledata struct {
49
    pcHeader     *pcHeader
50
    funcnametab  []byte
51
    cutab        []uint32
52
    filetab      []byte
53
    pctab        []byte
54
    pclntable    []byte
55
    ftab         []funcTab
56
    findfunctab  uintptr
57
    minpc, maxpc uintptr // first func address, last func address + last func size
58

59
    text, etext           uintptr // start/end of text, (etext-text) must be greater than MIN_FUNC
60
    noptrdata, enoptrdata uintptr
61
    data, edata           uintptr
62
    bss, ebss             uintptr
63
    noptrbss, enoptrbss   uintptr
64
    end, gcdata, gcbss    uintptr
65
    types, etypes         uintptr
66
    
67
    textsectmap []textSection // see runtime/symtab.go: textAddr()
68
    typelinks   []int32 // offsets from types
69
    itablinks   []*rt.GoItab
70

71
    ptab []ptabEntry
72

73
    pluginpath string
74
    pkghashes  []modulehash
75

76
    modulename   string
77
    modulehashes []modulehash
78

79
    hasmain uint8 // 1 if module contains the main function, 0 otherwise
80

81
    gcdatamask, gcbssmask bitVector
82

83
    typemap map[int32]*rt.GoType // offset to *_rtype in previous module
84

85
    bad bool // module failed to load and should be ignored
86

87
    next *moduledata
88
}
89

90
type _func struct {
91
    entry    uintptr // start pc, as offset from moduledata.text/pcHeader.textStart
92
    nameOff  int32  // function name, as index into moduledata.funcnametab.
93

94
    args        int32  // in/out args size
95
    deferreturn uint32 // offset of start of a deferreturn call instruction from entry, if any.
96

97
    pcsp      uint32 
98
    pcfile    uint32
99
    pcln      uint32
100
    npcdata   uint32
101
    cuOffset  uint32 // runtime.cutab offset of this function's CU
102
    funcID    uint8  // set for certain special runtime functions
103
    _         [2]byte // pad
104
    nfuncdata uint8   // 
105
    
106
    // The end of the struct is followed immediately by two variable-length
107
    // arrays that reference the pcdata and funcdata locations for this
108
    // function.
109

110
    // pcdata contains the offset into moduledata.pctab for the start of
111
    // that index's table. e.g.,
112
    // &moduledata.pctab[_func.pcdata[_PCDATA_UnsafePoint]] is the start of
113
    // the unsafe point table.
114
    //
115
    // An offset of 0 indicates that there is no table.
116
    //
117
    // pcdata [npcdata]uint32
118

119
    // funcdata contains the offset past moduledata.gofunc which contains a
120
    // pointer to that index's funcdata. e.g.,
121
    // *(moduledata.gofunc +  _func.funcdata[_FUNCDATA_ArgsPointerMaps]) is
122
    // the argument pointer map.
123
    //
124
    // An offset of ^uint32(0) indicates that there is no entry.
125
    //
126
    // funcdata [nfuncdata]uint32
127
}
128

129
type funcTab struct {
130
    entry   uintptr
131
    funcoff uintptr
132
}
133

134
type bitVector struct {
135
    n        int32 // # of bits
136
    bytedata *uint8
137
}
138

139
type ptabEntry struct {
140
    name int32
141
    typ  int32
142
}
143

144
type textSection struct {
145
    vaddr    uintptr // prelinked section vaddr
146
    end      uintptr // vaddr + section length
147
    baseaddr uintptr // relocated section address
148
}
149

150
type modulehash struct {
151
    modulename   string
152
    linktimehash string
153
    runtimehash  *string
154
}
155

156
// findfuncbucket is an array of these structures.
157
// Each bucket represents 4096 bytes of the text segment.
158
// Each subbucket represents 256 bytes of the text segment.
159
// To find a function given a pc, locate the bucket and subbucket for
160
// that pc. Add together the idx and subbucket value to obtain a
161
// function index. Then scan the functab array starting at that
162
// index to find the target function.
163
// This table uses 20 bytes for every 4096 bytes of code, or ~0.5% overhead.
164
type findfuncbucket struct {
165
    idx        uint32
166
    _SUBBUCKETS [16]byte
167
}
168

169

170
type compilationUnit struct {
171
    fileNames []string
172
}
173

174
func makeFtab(funcs []_func, maxpc uintptr) (ftab []funcTab, pclntabSize int64, startLocations []uint32) {
175
    // Allocate space for the pc->func table. This structure consists of a pc offset
176
    // and an offset to the func structure. After that, we have a single pc
177
    // value that marks the end of the last function in the binary.
178
    pclntabSize = int64(len(funcs)*2*int(_PtrSize) + int(_PtrSize))
179
    startLocations = make([]uint32, len(funcs))
180
    for i, f := range funcs {
181
        pclntabSize = rnd(pclntabSize, int64(_PtrSize))
182
        //writePCToFunc
183
        startLocations[i] = uint32(pclntabSize)
184
        pclntabSize += int64(uint8(_FUNC_SIZE) + f.nfuncdata*_PtrSize + uint8(f.npcdata)*4)
185
    }
186
    ftab = make([]funcTab, 0, len(funcs)+1)
187

188
    // write a map of pc->func info offsets 
189
    for i, f := range funcs {
190
        ftab = append(ftab, funcTab{uintptr(f.entry), uintptr(startLocations[i])})
191
    }
192

193
    // Final entry of table is just end pc offset.
194
    ftab = append(ftab, funcTab{maxpc, 0})
195
    return
196
}
197

198
// Pcln table format: [...]funcTab + [...]_Func
199
func makePclntable(size int64, startLocations []uint32, funcs []_func, maxpc uintptr, pcdataOffs [][]uint32, funcdataAddr uintptr, funcdataOffs [][]uint32) (pclntab []byte) {
200
    pclntab = make([]byte, size, size)
201

202
    // write a map of pc->func info offsets 
203
    offs := 0
204
    for i, f := range funcs {
205
        byteOrder.PutUint64(pclntab[offs:offs+8], uint64(f.entry))
206
        byteOrder.PutUint64(pclntab[offs+8:offs+16], uint64(startLocations[i]))
207
        offs += 16
208
    }
209
    // Final entry of table is just end pc offset.
210
    byteOrder.PutUint64(pclntab[offs:offs+8], uint64(maxpc))
211
    offs += 8
212

213
    // write func info table
214
    for i, f := range funcs {
215
        off := startLocations[i]
216

217
        // write _func structure to pclntab
218
        byteOrder.PutUint64(pclntab[off:off+8], uint64(f.entry))
219
        off += 8
220
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.nameOff))
221
        off += 4
222
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.args))
223
        off += 4
224
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.deferreturn))
225
        off += 4
226
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcsp))
227
        off += 4
228
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcfile))
229
        off += 4
230
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.pcln))
231
        off += 4
232
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.npcdata))
233
        off += 4
234
        byteOrder.PutUint32(pclntab[off:off+4], uint32(f.cuOffset))
235
        off += 4
236
        pclntab[off] = f.funcID
237
        // NOTICE: _[2]byte alignment
238
        off += 3
239
        pclntab[off] = f.nfuncdata
240
        off += 1
241

242
        // NOTICE: _func.pcdata always starts from PcUnsafePoint, which is index 3
243
        for j := 3; j < len(pcdataOffs[i]); j++ {
244
            byteOrder.PutUint32(pclntab[off:off+4], uint32(pcdataOffs[i][j]))
245
            off += 4
246
        }
247

248
        off = uint32(rnd(int64(off), int64(_PtrSize)))
249

250
        // funcdata refs as offsets from gofunc
251
        for _, funcdata := range funcdataOffs[i] {
252
            if funcdata == _INVALID_FUNCDATA_OFFSET {
253
                byteOrder.PutUint64(pclntab[off:off+8], 0)
254
            } else {
255
                byteOrder.PutUint64(pclntab[off:off+8], uint64(funcdataAddr)+uint64(funcdata))
256
            }
257
            off += 8
258
        }
259
    }
260

261
    return
262
}
263

264
// findfunc table used to map pc to belonging func, 
265
// returns the index in the func table.
266
//
267
// All text section are divided into buckets sized _BUCKETSIZE(4K):
268
//   every bucket is divided into _SUBBUCKETS sized _SUB_BUCKETSIZE(64),
269
//   and it has a base idx to plus the offset stored in jth subbucket.
270
// see findfunc() in runtime/symtab.go
271
func writeFindfunctab(out *[]byte, ftab []funcTab) (start int) {
272
    start = len(*out)
273

274
    max := ftab[len(ftab)-1].entry
275
    min := ftab[0].entry
276
    nbuckets := (max - min + _BUCKETSIZE - 1) / _BUCKETSIZE
277
    n := (max - min + _SUB_BUCKETSIZE - 1) / _SUB_BUCKETSIZE
278

279
    tab := make([]findfuncbucket, 0, nbuckets)
280
    var s, e = 0, 0
281
    for i := 0; i<int(nbuckets); i++ {
282
        // store the start func of the bucket
283
        var fb = findfuncbucket{idx: uint32(s)}
284

285
        // find the last e-th func of the bucket
286
        var pc = min + uintptr((i+1)*_BUCKETSIZE)
287
        for ; e < len(ftab)-1 && ftab[e+1].entry <= pc; e++ {}
288
        
289
        for j := 0; j<_SUBBUCKETS && (i*_SUBBUCKETS+j)<int(n); j++ {
290
            // store the start func of the subbucket
291
            fb._SUBBUCKETS[j] = byte(uint32(s) - fb.idx)
292
            
293
            // find the s-th end func of the subbucket
294
            pc = min + uintptr(i*_BUCKETSIZE) + uintptr((j+1)*_SUB_BUCKETSIZE)
295
            for ; s < len(ftab)-1 && ftab[s+1].entry <= pc; s++ {}            
296
        }
297

298
        s = e
299
        tab = append(tab, fb)
300
    }
301

302
    // write findfuncbucket
303
    if len(tab) > 0 {
304
        size := int(unsafe.Sizeof(findfuncbucket{}))*len(tab)
305
        *out = append(*out, rt.BytesFrom(unsafe.Pointer(&tab[0]), size, size)...)
306
    }
307
    return 
308
}
309

310
func makeModuledata(name string, filenames []string, funcsp *[]Func, text []byte) (mod *moduledata) {
311
    mod = new(moduledata)
312
    mod.modulename = name
313

314
    // sort funcs by entry
315
    funcs := *funcsp
316
    sort.Slice(funcs, func(i, j int) bool {
317
        return funcs[i].EntryOff < funcs[j].EntryOff
318
    })
319
    *funcsp = funcs
320

321
    // make filename table
322
    cu := make([]string, 0, len(filenames))
323
    cu = append(cu, filenames...)
324
    cutab, filetab, cuOffs := makeFilenametab([]compilationUnit{{cu}})
325
    mod.cutab = cutab
326
    mod.filetab = filetab
327

328
    // make funcname table
329
    funcnametab, nameOffs := makeFuncnameTab(funcs)
330
    mod.funcnametab = funcnametab
331

332
    // mmap() text and funcdata segements
333
    p := os.Getpagesize()
334
    size := int(rnd(int64(len(text)), int64(p)))
335
    addr := mmap(size)
336
    // copy the machine code
337
    s := rt.BytesFrom(unsafe.Pointer(addr), len(text), size)
338
    copy(s, text)
339
    // make it executable
340
    mprotect(addr, size)
341

342
    // assign addresses
343
    mod.text = addr
344
    mod.etext = addr + uintptr(size)
345
    mod.minpc = addr
346
    mod.maxpc = addr + uintptr(len(text))
347

348
    // make pcdata table
349
    // NOTICE: _func only use offset to index pcdata, thus no need mmap() pcdata 
350
    cuOff := cuOffs[0]
351
    pctab, pcdataOffs, _funcs := makePctab(funcs, addr, cuOff, nameOffs)
352
    mod.pctab = pctab
353

354
    // write func data
355
    // NOTICE: _func use mod.gofunc+offset to directly point funcdata, thus need cache funcdata
356
    // TODO: estimate accurate capacity
357
    cache := make([]byte, 0, len(funcs)*int(_PtrSize)) 
358
    fstart, funcdataOffs := writeFuncdata(&cache, funcs)
359

360
    // make pc->func (binary search) func table
361
    ftab, pclntSize, startLocations := makeFtab(_funcs, mod.maxpc)
362
    mod.ftab = ftab
363

364
    // write pc->func (modmap) findfunc table
365
    ffstart := writeFindfunctab(&cache, ftab)
366

367
    // cache funcdata and findfuncbucket
368
    moduleCache.Lock()
369
    moduleCache.m[mod] = cache
370
    moduleCache.Unlock()
371
    mod.findfunctab = uintptr(rt.IndexByte(cache, ffstart))
372
    funcdataAddr := uintptr(rt.IndexByte(cache, fstart))
373

374
    // make pclnt table
375
    pclntab := makePclntable(pclntSize, startLocations, _funcs, mod.maxpc, pcdataOffs, funcdataAddr, funcdataOffs)
376
    mod.pclntable = pclntab
377

378
    // make pc header
379
    mod.pcHeader = &pcHeader {
380
        magic   : _Magic,
381
        minLC   : _MinLC,
382
        ptrSize : _PtrSize,
383
        nfunc   : len(funcs),
384
        nfiles: uint(len(cu)),
385
        funcnameOffset: getOffsetOf(moduledata{}, "funcnametab"),
386
        cuOffset: getOffsetOf(moduledata{}, "cutab"),
387
        filetabOffset: getOffsetOf(moduledata{}, "filetab"),
388
        pctabOffset: getOffsetOf(moduledata{}, "pctab"),
389
        pclnOffset: getOffsetOf(moduledata{}, "pclntable"),
390
    }
391

392
    // sepecial case: gcdata and gcbss must by non-empty
393
    mod.gcdata = uintptr(unsafe.Pointer(&emptyByte))
394
    mod.gcbss = uintptr(unsafe.Pointer(&emptyByte))
395

396
    return
397
}
398

399
// makePctab generates pcdelta->valuedelta tables for functions,
400
// and returns the table and the entry offset of every kind pcdata in the table.
401
func makePctab(funcs []Func, addr uintptr, cuOffset uint32, nameOffset []int32) (pctab []byte, pcdataOffs [][]uint32, _funcs []_func) {
402
    _funcs = make([]_func, len(funcs))
403

404
    // Pctab offsets of 0 are considered invalid in the runtime. We respect
405
    // that by just padding a single byte at the beginning of runtime.pctab,
406
    // that way no real offsets can be zero.
407
    pctab = make([]byte, 1, 12*len(funcs)+1)
408
    pcdataOffs = make([][]uint32, len(funcs))
409

410
    for i, f := range funcs {
411
        _f := &_funcs[i]
412

413
        var writer = func(pc *Pcdata) {
414
            var ab []byte
415
            var err error
416
            if pc != nil {
417
                ab, err = pc.MarshalBinary()
418
                if err != nil {
419
                    panic(err)
420
                }
421
                pcdataOffs[i] = append(pcdataOffs[i], uint32(len(pctab)))
422
            } else {
423
                ab = []byte{0}
424
                pcdataOffs[i] = append(pcdataOffs[i], _PCDATA_INVALID_OFFSET)
425
            }
426
            pctab = append(pctab, ab...)
427
        }
428

429
        if f.Pcsp != nil {
430
            _f.pcsp = uint32(len(pctab))
431
        }
432
        writer(f.Pcsp)
433
        if f.Pcfile != nil {
434
            _f.pcfile = uint32(len(pctab))
435
        }
436
        writer(f.Pcfile)
437
        if f.Pcline != nil {
438
            _f.pcln = uint32(len(pctab))
439
        }
440
        writer(f.Pcline)
441
        writer(f.PcUnsafePoint)
442
        writer(f.PcStackMapIndex)
443
        writer(f.PcInlTreeIndex)
444
        writer(f.PcArgLiveIndex)
445
        
446
        _f.entry = addr + uintptr(f.EntryOff)
447
        _f.nameOff = nameOffset[i]
448
        _f.args = f.ArgsSize
449
        _f.deferreturn = f.DeferReturn
450
        // NOTICE: _func.pcdata is always as [PCDATA_UnsafePoint(0) : PCDATA_ArgLiveIndex(3)]
451
        _f.npcdata = uint32(_N_PCDATA)
452
        _f.cuOffset = cuOffset
453
        _f.funcID = f.ID
454
        _f.nfuncdata = uint8(_N_FUNCDATA)
455
    }
456

457
    return
458
}
459

460
func registerFunction(name string, pc uintptr, textSize uintptr, fp int, args int, size uintptr, argptrs uintptr, localptrs uintptr) {} 
461