vminfo_darwin.go

     1  // Copyright 2023 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package pprof
     6  
     7  import (
     8  	"internal/byteorder"
     9  	"os"
    10  	"unsafe"
    11  )
    12  
    13  func isExecutable(protection int32) bool {
    14  	return (protection&_VM_PROT_EXECUTE) != 0 && (protection&_VM_PROT_READ) != 0
    15  }
    16  
    17  // machVMInfo uses the mach_vm_region region system call to add mapping entries
    18  // for the text region of the running process.
    19  func machVMInfo(addMapping func(lo, hi, offset uint64, file, buildID string)) bool {
    20  	added := false
    21  	var addr uint64 = 0x1
    22  	for {
    23  		var memRegionSize uint64
    24  		var info machVMRegionBasicInfoData
    25  		// Get the first address and page size.
    26  		kr := mach_vm_region(
    27  			&addr,
    28  			&memRegionSize,
    29  			unsafe.Pointer(&info))
    30  		if kr != 0 {
    31  			if kr == _MACH_SEND_INVALID_DEST {
    32  				// No more memory regions.
    33  				return true
    34  			}
    35  			return added // return true if at least one mapping was added
    36  		}
    37  		if isExecutable(info.Protection) {
    38  			// NOTE: the meaning/value of Offset is unclear. However,
    39  			// this likely doesn't matter as the text segment's file
    40  			// offset is usually 0.
    41  			addMapping(addr,
    42  				addr+memRegionSize,
    43  				byteorder.LEUint64(info.Offset[:]),
    44  				regionFilename(addr),
    45  				"")
    46  			added = true
    47  		}
    48  		addr += memRegionSize
    49  	}
    50  }
    51  
    52  func regionFilename(address uint64) string {
    53  	buf := make([]byte, _MAXPATHLEN)
    54  	r := proc_regionfilename(
    55  		os.Getpid(),
    56  		address,
    57  		unsafe.SliceData(buf),
    58  		int64(cap(buf)))
    59  	if r == 0 {
    60  		return ""
    61  	}
    62  	return string(buf[:r])
    63  }
    64  
    65  // mach_vm_region and proc_regionfilename are implemented by
    66  // the runtime package (runtime/sys_darwin.go).
    67  //
    68  //go:noescape
    69  func mach_vm_region(address, region_size *uint64, info unsafe.Pointer) int32
    70  
    71  //go:noescape
    72  func proc_regionfilename(pid int, address uint64, buf *byte, buflen int64) int32
    73
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