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Fix go:linkname for mmap #107

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merged 2 commits into from
Jun 25, 2024
Merged

Fix go:linkname for mmap #107

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1009e64
Unsafe mmap
ncruces Jun 13, 2024
462fbc7
More.
ncruces Jun 25, 2024
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2 changes: 1 addition & 1 deletion go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ require (
github.com/tetratelabs/wazero v1.7.3
golang.org/x/crypto v0.24.0
golang.org/x/sync v0.7.0
golang.org/x/sys v0.21.0
golang.org/x/sys v0.21.1-0.20240625003756-daa239428c2d
golang.org/x/text v0.16.0
lukechampine.com/adiantum v1.1.1
)
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4 changes: 2 additions & 2 deletions go.sum
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Expand Up @@ -10,8 +10,8 @@ golang.org/x/crypto v0.24.0 h1:mnl8DM0o513X8fdIkmyFE/5hTYxbwYOjDS/+rK6qpRI=
golang.org/x/crypto v0.24.0/go.mod h1:Z1PMYSOR5nyMcyAVAIQSKCDwalqy85Aqn1x3Ws4L5DM=
golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
golang.org/x/sys v0.21.1-0.20240625003756-daa239428c2d h1:+oefiaQuWDtgsRTCSGwaYzgW+OElRO3uOsTt564+/N8=
golang.org/x/sys v0.21.1-0.20240625003756-daa239428c2d/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
lukechampine.com/adiantum v1.1.1 h1:4fp6gTxWCqpEbLy40ExiYDDED3oUNWx5cTqBCtPdZqA=
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20 changes: 6 additions & 14 deletions internal/util/mmap.go
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Expand Up @@ -46,7 +46,7 @@ func (s *mmapState) new(ctx context.Context, mod api.Module, size int32) *Mapped
// Save the newly allocated region.
ptr := uint32(stack[0])
buf := View(mod, ptr, uint64(size))
addr := uintptr(unsafe.Pointer(&buf[0]))
addr := unsafe.Pointer(&buf[0])
s.regions = append(s.regions, &MappedRegion{
Ptr: ptr,
addr: addr,
Expand All @@ -56,7 +56,7 @@ func (s *mmapState) new(ctx context.Context, mod api.Module, size int32) *Mapped
}

type MappedRegion struct {
addr uintptr
addr unsafe.Pointer
Ptr uint32
size int32
used bool
Expand All @@ -76,23 +76,15 @@ func (r *MappedRegion) Unmap() error {
// We can't munmap the region, otherwise it could be remaped.
// Instead, convert it to a protected, private, anonymous mapping.
// If successful, it can be reused for a subsequent mmap.
_, err := mmap(r.addr, uintptr(r.size),
unix.PROT_NONE, unix.MAP_PRIVATE|unix.MAP_ANON|unix.MAP_FIXED,
-1, 0)
_, err := unix.MmapPtr(-1, 0, r.addr, uintptr(r.size),
unix.PROT_NONE, unix.MAP_PRIVATE|unix.MAP_FIXED|unix.MAP_ANON)
r.used = err != nil
return err
}

func (r *MappedRegion) mmap(f *os.File, offset int64, prot int) error {
_, err := mmap(r.addr, uintptr(r.size),
prot, unix.MAP_SHARED|unix.MAP_FIXED,
int(f.Fd()), offset)
_, err := unix.MmapPtr(int(f.Fd()), offset, r.addr, uintptr(r.size),
prot, unix.MAP_SHARED|unix.MAP_FIXED)
r.used = err == nil
return err
}

// We need the low level mmap for MAP_FIXED to work.
// Bind the syscall version hoping that it is more stable.

//go:linkname mmap syscall.mmap
func mmap(addr, length uintptr, prot, flag, fd int, pos int64) (*byte, error)