syscall: replace lstat, lchown, stat to please Android O

Implement Lstat with fstatat and Lchown with Fchownat on
linux/amd64, linux/arm and linux/386. Furthermore, implement Stat
with fstatat on linux/arm and linux/386. Linux/arm64 already had
similar replacements.

The fstatat and fchownat system calls were added in kernel 2.6.16,
which is before the Go minimum, 2.6.23.

The three syscalls then match the android bionic implementation
and avoids the Android O seccomp filter.

Fixes #27797

Change-Id: I07fd5506955d454a1a660fef5af0e1ac1ecb0959
Reviewed-on: https://go-review.googlesource.com/136795
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/syscall/syscall_linux_386.go b/src/syscall/syscall_linux_386.go
index 49db72450fbb7d47d0c0e4dcd378a36d8897d775..6e162ebb41f34d454b891158abe0d4b7dde4c7f9 100644 (file)
--- a/src/syscall/syscall_linux_386.go
+++ b/src/syscall/syscall_linux_386.go
@@ -62,8 +62,6 @@ func Pipe2(p []int, flags int) (err error) {
 //sysnb        InotifyInit() (fd int, err error)
 //sys  Ioperm(from int, num int, on int) (err error)
 //sys  Iopl(level int) (err error)
-//sys  Lchown(path string, uid int, gid int) (err error) = SYS_LCHOWN32
-//sys  Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys  Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys  Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
 //sys  sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
@@ -74,7 +72,6 @@ func Pipe2(p []int, flags int) (err error) {
 //sysnb        Setresuid(ruid int, euid int, suid int) (err error) = SYS_SETRESUID32
 //sysnb        Setreuid(ruid int, euid int) (err error) = SYS_SETREUID32
 //sys  Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
-//sys  Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
 //sys  SyncFileRange(fd int, off int64, n int64, flags int) (err error)
 //sys  Truncate(path string, length int64) (err error) = SYS_TRUNCATE64
 //sysnb        getgroups(n int, list *_Gid_t) (nn int, err error) = SYS_GETGROUPS32
@@ -84,6 +81,18 @@ func Pipe2(p []int, flags int) (err error) {
 //sys  mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
 //sys  EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 
+func Stat(path string, stat *Stat_t) (err error) {
+       return fstatat(_AT_FDCWD, path, stat, 0)
+}
+
+func Lchown(path string, uid int, gid int) (err error) {
+       return Fchownat(_AT_FDCWD, path, uid, gid, _AT_SYMLINK_NOFOLLOW)
+}
+
+func Lstat(path string, stat *Stat_t) (err error) {
+       return fstatat(_AT_FDCWD, path, stat, _AT_SYMLINK_NOFOLLOW)
+}
+
 func mmap(addr uintptr, length uintptr, prot int, flags int, fd int, offset int64) (xaddr uintptr, err error) {
        page := uintptr(offset / 4096)
        if offset != int64(page)*4096 {

diff --git a/src/syscall/syscall_linux_amd64.go b/src/syscall/syscall_linux_amd64.go
index 1a21d9db6f2b494465253d8baae9a5abf94e0b6f..f740ab4e72d1a5bb1ec5857a55044995759ff032 100644 (file)
--- a/src/syscall/syscall_linux_amd64.go
+++ b/src/syscall/syscall_linux_amd64.go
@@ -22,9 +22,7 @@ const (
 //sysnb        InotifyInit() (fd int, err error)
 //sys  Ioperm(from int, num int, on int) (err error)
 //sys  Iopl(level int) (err error)
-//sys  Lchown(path string, uid int, gid int) (err error)
 //sys  Listen(s int, n int) (err error)
-//sys  Lstat(path string, stat *Stat_t) (err error)
 //sys  Pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
 //sys  Pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
 //sys  Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
@@ -66,6 +64,14 @@ func Stat(path string, stat *Stat_t) (err error) {
        return fstatat(_AT_FDCWD, path, stat, 0)
 }
 
+func Lchown(path string, uid int, gid int) (err error) {
+       return Fchownat(_AT_FDCWD, path, uid, gid, _AT_SYMLINK_NOFOLLOW)
+}
+
+func Lstat(path string, stat *Stat_t) (err error) {
+       return fstatat(_AT_FDCWD, path, stat, _AT_SYMLINK_NOFOLLOW)
+}
+
 //go:noescape
 func gettimeofday(tv *Timeval) (err Errno)
 

diff --git a/src/syscall/syscall_linux_arm.go b/src/syscall/syscall_linux_arm.go
index b0c0ac7c4fae66ad79d2af7cb73f307f5d857d31..65543193e15ebef0eb7b2c4bc84d3f405c94ed4b 100644 (file)
--- a/src/syscall/syscall_linux_arm.go
+++ b/src/syscall/syscall_linux_arm.go
@@ -83,9 +83,7 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sysnb        Getgid() (gid int) = SYS_GETGID32
 //sysnb        Getuid() (uid int) = SYS_GETUID32
 //sysnb        InotifyInit() (fd int, err error)
-//sys  Lchown(path string, uid int, gid int) (err error) = SYS_LCHOWN32
 //sys  Listen(s int, n int) (err error)
-//sys  Lstat(path string, stat *Stat_t) (err error) = SYS_LSTAT64
 //sys  sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) = SYS_SENDFILE64
 //sys  Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) = SYS__NEWSELECT
 //sys  Setfsgid(gid int) (err error) = SYS_SETFSGID32
@@ -96,7 +94,6 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sysnb        Setreuid(ruid int, euid int) (err error) = SYS_SETREUID32
 //sys  Shutdown(fd int, how int) (err error)
 //sys  Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error)
-//sys  Stat(path string, stat *Stat_t) (err error) = SYS_STAT64
 
 // Vsyscalls on amd64.
 //sysnb        Gettimeofday(tv *Timeval) (err error)
@@ -110,6 +107,18 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 //sys  mmap2(addr uintptr, length uintptr, prot int, flags int, fd int, pageOffset uintptr) (xaddr uintptr, err error)
 //sys  EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 
+func Stat(path string, stat *Stat_t) (err error) {
+       return fstatat(_AT_FDCWD, path, stat, 0)
+}
+
+func Lchown(path string, uid int, gid int) (err error) {
+       return Fchownat(_AT_FDCWD, path, uid, gid, _AT_SYMLINK_NOFOLLOW)
+}
+
+func Lstat(path string, stat *Stat_t) (err error) {
+       return fstatat(_AT_FDCWD, path, stat, _AT_SYMLINK_NOFOLLOW)
+}
+
 func Fstatfs(fd int, buf *Statfs_t) (err error) {
        _, _, e := Syscall(SYS_FSTATFS64, uintptr(fd), unsafe.Sizeof(*buf), uintptr(unsafe.Pointer(buf)))
        if e != 0 {

diff --git a/src/syscall/zsyscall_linux_386.go b/src/syscall/zsyscall_linux_386.go
index 62827f16dc34683dde8f4ebc84f53c86183f9faa..0882494c470dde6c0c4638bdea7a87ffca66be4f 100644 (file)
--- a/src/syscall/zsyscall_linux_386.go
+++ b/src/syscall/zsyscall_linux_386.go
@@ -1276,36 +1276,6 @@ func Iopl(level int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Lchown(path string, uid int, gid int) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LCHOWN32, uintptr(unsafe.Pointer(_p0)), uintptr(uid), uintptr(gid))
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
-func Lstat(path string, stat *Stat_t) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LSTAT64, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Pread(fd int, p []byte, offset int64) (n int, err error) {
        var _p0 unsafe.Pointer
        if len(p) > 0 {
@@ -1422,21 +1392,6 @@ func Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Stat(path string, stat *Stat_t) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_STAT64, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func SyncFileRange(fd int, off int64, n int64, flags int) (err error) {
        _, _, e1 := Syscall6(SYS_SYNC_FILE_RANGE, uintptr(fd), uintptr(off), uintptr(off>>32), uintptr(n), uintptr(n>>32), uintptr(flags))
        if e1 != 0 {

diff --git a/src/syscall/zsyscall_linux_amd64.go b/src/syscall/zsyscall_linux_amd64.go
index b6638269bebb8cdc59dfc50f278ce2693d233585..9f2046bf93fee0a45bb4fa4693d0e4811d2da80e 100644 (file)
--- a/src/syscall/zsyscall_linux_amd64.go
+++ b/src/syscall/zsyscall_linux_amd64.go
@@ -1261,21 +1261,6 @@ func Iopl(level int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Lchown(path string, uid int, gid int) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LCHOWN, uintptr(unsafe.Pointer(_p0)), uintptr(uid), uintptr(gid))
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Listen(s int, n int) (err error) {
        _, _, e1 := Syscall(SYS_LISTEN, uintptr(s), uintptr(n), 0)
        if e1 != 0 {
@@ -1286,21 +1271,6 @@ func Listen(s int, n int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Lstat(path string, stat *Stat_t) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LSTAT, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Pread(fd int, p []byte, offset int64) (n int, err error) {
        var _p0 unsafe.Pointer
        if len(p) > 0 {

diff --git a/src/syscall/zsyscall_linux_arm.go b/src/syscall/zsyscall_linux_arm.go
index bb20d6e9463ea4feb7717bc8edf326a3a9c11209..3d099aa16df65f3043d1e9a47289b1802a9e8675 100644 (file)
--- a/src/syscall/zsyscall_linux_arm.go
+++ b/src/syscall/zsyscall_linux_arm.go
@@ -1415,21 +1415,6 @@ func InotifyInit() (fd int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Lchown(path string, uid int, gid int) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LCHOWN32, uintptr(unsafe.Pointer(_p0)), uintptr(uid), uintptr(gid))
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Listen(s int, n int) (err error) {
        _, _, e1 := Syscall(SYS_LISTEN, uintptr(s), uintptr(n), 0)
        if e1 != 0 {
@@ -1440,21 +1425,6 @@ func Listen(s int, n int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Lstat(path string, stat *Stat_t) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_LSTAT64, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
        r0, _, e1 := Syscall6(SYS_SENDFILE64, uintptr(outfd), uintptr(infd), uintptr(unsafe.Pointer(offset)), uintptr(count), 0, 0)
        written = int(r0)
@@ -1558,21 +1528,6 @@ func Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Stat(path string, stat *Stat_t) (err error) {
-       var _p0 *byte
-       _p0, err = BytePtrFromString(path)
-       if err != nil {
-               return
-       }
-       _, _, e1 := Syscall(SYS_STAT64, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-       if e1 != 0 {
-               err = errnoErr(e1)
-       }
-       return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Gettimeofday(tv *Timeval) (err error) {
        _, _, e1 := RawSyscall(SYS_GETTIMEOFDAY, uintptr(unsafe.Pointer(tv)), 0, 0)
        if e1 != 0 {