admin/llgo
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

syscall: exec linux

Browse Source
This commit is contained in:
xushiwei
2024-07-12 01:07:12 +08:00
parent 68f70af2f3
commit 452ee7a103
1 changed files with 733 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

733
internal/lib/syscall/exec_linux.go Normal file
View File

@@ -0,0 +1,733 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build linux
package syscall
// Linux unshare/clone/clone2/clone3 flags, architecture-independent,
// copied from linux/sched.h.
const (
CLONE_VM = 0x00000100 // set if VM shared between processes
CLONE_FS = 0x00000200 // set if fs info shared between processes
CLONE_FILES = 0x00000400 // set if open files shared between processes
CLONE_SIGHAND = 0x00000800 // set if signal handlers and blocked signals shared
CLONE_PIDFD = 0x00001000 // set if a pidfd should be placed in parent
CLONE_PTRACE = 0x00002000 // set if we want to let tracing continue on the child too
CLONE_VFORK = 0x00004000 // set if the parent wants the child to wake it up on mm_release
CLONE_PARENT = 0x00008000 // set if we want to have the same parent as the cloner
CLONE_THREAD = 0x00010000 // Same thread group?
CLONE_NEWNS = 0x00020000 // New mount namespace group
CLONE_SYSVSEM = 0x00040000 // share system V SEM_UNDO semantics
CLONE_SETTLS = 0x00080000 // create a new TLS for the child
CLONE_PARENT_SETTID = 0x00100000 // set the TID in the parent
CLONE_CHILD_CLEARTID = 0x00200000 // clear the TID in the child
CLONE_DETACHED = 0x00400000 // Unused, ignored
CLONE_UNTRACED = 0x00800000 // set if the tracing process can't force CLONE_PTRACE on this clone
CLONE_CHILD_SETTID = 0x01000000 // set the TID in the child
CLONE_NEWCGROUP = 0x02000000 // New cgroup namespace
CLONE_NEWUTS = 0x04000000 // New utsname namespace
CLONE_NEWIPC = 0x08000000 // New ipc namespace
CLONE_NEWUSER = 0x10000000 // New user namespace
CLONE_NEWPID = 0x20000000 // New pid namespace
CLONE_NEWNET = 0x40000000 // New network namespace
CLONE_IO = 0x80000000 // Clone io context
// Flags for the clone3() syscall.
CLONE_CLEAR_SIGHAND = 0x100000000 // Clear any signal handler and reset to SIG_DFL.
CLONE_INTO_CGROUP = 0x200000000 // Clone into a specific cgroup given the right permissions.
// Cloning flags intersect with CSIGNAL so can be used with unshare and clone3
// syscalls only:
CLONE_NEWTIME = 0x00000080 // New time namespace
)
// SysProcIDMap holds Container ID to Host ID mappings used for User Namespaces in Linux.
// See user_namespaces(7).
type SysProcIDMap struct {
ContainerID int // Container ID.
HostID int // Host ID.
Size int // Size.
}
type SysProcAttr struct {
Chroot string // Chroot.
Credential *Credential // Credential.
// Ptrace tells the child to call ptrace(PTRACE_TRACEME).
// Call runtime.LockOSThread before starting a process with this set,
// and don't call UnlockOSThread until done with PtraceSyscall calls.
Ptrace bool
Setsid bool // Create session.
// Setpgid sets the process group ID of the child to Pgid,
// or, if Pgid == 0, to the new child's process ID.
Setpgid bool
// Setctty sets the controlling terminal of the child to
// file descriptor Ctty. Ctty must be a descriptor number
// in the child process: an index into ProcAttr.Files.
// This is only meaningful if Setsid is true.
Setctty bool
Noctty bool // Detach fd 0 from controlling terminal
Ctty int // Controlling TTY fd
// Foreground places the child process group in the foreground.
// This implies Setpgid. The Ctty field must be set to
// the descriptor of the controlling TTY.
// Unlike Setctty, in this case Ctty must be a descriptor
// number in the parent process.
Foreground bool
Pgid int // Child's process group ID if Setpgid.
// Pdeathsig, if non-zero, is a signal that the kernel will send to
// the child process when the creating thread dies. Note that the signal
// is sent on thread termination, which may happen before process termination.
// There are more details at https://go.dev/issue/27505.
Pdeathsig Signal
Cloneflags uintptr // Flags for clone calls (Linux only)
Unshareflags uintptr // Flags for unshare calls (Linux only)
UidMappings []SysProcIDMap // User ID mappings for user namespaces.
GidMappings []SysProcIDMap // Group ID mappings for user namespaces.
// GidMappingsEnableSetgroups enabling setgroups syscall.
// If false, then setgroups syscall will be disabled for the child process.
// This parameter is no-op if GidMappings == nil. Otherwise for unprivileged
// users this should be set to false for mappings work.
GidMappingsEnableSetgroups bool
AmbientCaps []uintptr // Ambient capabilities (Linux only)
UseCgroupFD bool // Whether to make use of the CgroupFD field.
CgroupFD int // File descriptor of a cgroup to put the new process into.
}
var (
none = [...]byte{'n', 'o', 'n', 'e', 0}
slash = [...]byte{'/', 0}
)
/* TODO(xsw):
// Implemented in runtime package.
func runtime_BeforeFork()
func runtime_AfterFork()
func runtime_AfterForkInChild()
*/
// Fork, dup fd onto 0..len(fd), and exec(argv0, argvv, envv) in child.
// If a dup or exec fails, write the errno error to pipe.
// (Pipe is close-on-exec so if exec succeeds, it will be closed.)
// In the child, this function must not acquire any locks, because
// they might have been locked at the time of the fork. This means
// no rescheduling, no malloc calls, and no new stack segments.
// For the same reason compiler does not race instrument it.
// The calls to RawSyscall are okay because they are assembly
// functions that do not grow the stack.
//
//go:norace
func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr *ProcAttr, sys *SysProcAttr, pipe int) (pid int, err Errno) {
/* TODO(xsw):
// Set up and fork. This returns immediately in the parent or
// if there's an error.
upid, err, mapPipe, locked := forkAndExecInChild1(argv0, argv, envv, chroot, dir, attr, sys, pipe)
if locked {
runtime_AfterFork()
}
if err != 0 {
return 0, err
}
// parent; return PID
pid = int(upid)
if sys.UidMappings != nil || sys.GidMappings != nil {
Close(mapPipe[0])
var err2 Errno
// uid/gid mappings will be written after fork and unshare(2) for user
// namespaces.
if sys.Unshareflags&CLONE_NEWUSER == 0 {
if err := writeUidGidMappings(pid, sys); err != nil {
err2 = err.(Errno)
}
}
RawSyscall(SYS_WRITE, uintptr(mapPipe[1]), uintptr(unsafe.Pointer(&err2)), unsafe.Sizeof(err2))
Close(mapPipe[1])
}
return pid, 0
*/
panic("todo: syscall.forkAndExecInChild")
}
const _LINUX_CAPABILITY_VERSION_3 = 0x20080522
type capHeader struct {
version uint32
pid int32
}
type capData struct {
effective uint32
permitted uint32
inheritable uint32
}
type caps struct {
hdr capHeader
data [2]capData
}
// See CAP_TO_INDEX in linux/capability.h:
func capToIndex(cap uintptr) uintptr { return cap >> 5 }
// See CAP_TO_MASK in linux/capability.h:
func capToMask(cap uintptr) uint32 { return 1 << uint(cap&31) }
// cloneArgs holds arguments for clone3 Linux syscall.
type cloneArgs struct {
flags uint64 // Flags bit mask
pidFD uint64 // Where to store PID file descriptor (int *)
childTID uint64 // Where to store child TID, in child's memory (pid_t *)
parentTID uint64 // Where to store child TID, in parent's memory (pid_t *)
exitSignal uint64 // Signal to deliver to parent on child termination
stack uint64 // Pointer to lowest byte of stack
stackSize uint64 // Size of stack
tls uint64 // Location of new TLS
setTID uint64 // Pointer to a pid_t array (since Linux 5.5)
setTIDSize uint64 // Number of elements in set_tid (since Linux 5.5)
cgroup uint64 // File descriptor for target cgroup of child (since Linux 5.7)
}
// forkAndExecInChild1 implements the body of forkAndExecInChild up to
// the parent's post-fork path. This is a separate function so we can
// separate the child's and parent's stack frames if we're using
// vfork.
//
// This is go:noinline because the point is to keep the stack frames
// of this and forkAndExecInChild separate.
//
//go:noinline
//go:norace
//go:nocheckptr
func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr *ProcAttr, sys *SysProcAttr, pipe int) (pid uintptr, err1 Errno, mapPipe [2]int, locked bool) {
/* TODO(xsw):
// Defined in linux/prctl.h starting with Linux 4.3.
const (
PR_CAP_AMBIENT = 0x2f
PR_CAP_AMBIENT_RAISE = 0x2
)
// vfork requires that the child not touch any of the parent's
// active stack frames. Hence, the child does all post-fork
// processing in this stack frame and never returns, while the
// parent returns immediately from this frame and does all
// post-fork processing in the outer frame.
//
// Declare all variables at top in case any
// declarations require heap allocation (e.g., err2).
// ":=" should not be used to declare any variable after
// the call to runtime_BeforeFork.
//
// NOTE(bcmills): The allocation behavior described in the above comment
// seems to lack a corresponding test, and it may be rendered invalid
// by an otherwise-correct change in the compiler.
var (
err2 Errno
nextfd int
i int
caps caps
fd1, flags uintptr
puid, psetgroups, pgid []byte
uidmap, setgroups, gidmap []byte
clone3 *cloneArgs
pgrp int32
dirfd int
cred *Credential
ngroups, groups uintptr
c uintptr
)
rlim, rlimOK := origRlimitNofile.Load().(Rlimit)
if sys.UidMappings != nil {
puid = []byte("/proc/self/uid_map\000")
uidmap = formatIDMappings(sys.UidMappings)
}
if sys.GidMappings != nil {
psetgroups = []byte("/proc/self/setgroups\000")
pgid = []byte("/proc/self/gid_map\000")
if sys.GidMappingsEnableSetgroups {
setgroups = []byte("allow\000")
} else {
setgroups = []byte("deny\000")
}
gidmap = formatIDMappings(sys.GidMappings)
}
// Record parent PID so child can test if it has died.
ppid, _ := rawSyscallNoError(SYS_GETPID, 0, 0, 0)
// Guard against side effects of shuffling fds below.
// Make sure that nextfd is beyond any currently open files so
// that we can't run the risk of overwriting any of them.
fd := make([]int, len(attr.Files))
nextfd = len(attr.Files)
for i, ufd := range attr.Files {
if nextfd < int(ufd) {
nextfd = int(ufd)
}
fd[i] = int(ufd)
}
nextfd++
// Allocate another pipe for parent to child communication for
// synchronizing writing of User ID/Group ID mappings.
if sys.UidMappings != nil || sys.GidMappings != nil {
if err := forkExecPipe(mapPipe[:]); err != nil {
err1 = err.(Errno)
return
}
}
flags = sys.Cloneflags
if sys.Cloneflags&CLONE_NEWUSER == 0 && sys.Unshareflags&CLONE_NEWUSER == 0 {
flags |= CLONE_VFORK | CLONE_VM
}
// Whether to use clone3.
if sys.UseCgroupFD {
clone3 = &cloneArgs{
flags: uint64(flags) | CLONE_INTO_CGROUP,
exitSignal: uint64(SIGCHLD),
cgroup: uint64(sys.CgroupFD),
}
} else if flags&CLONE_NEWTIME != 0 {
clone3 = &cloneArgs{
flags: uint64(flags),
exitSignal: uint64(SIGCHLD),
}
}
// About to call fork.
// No more allocation or calls of non-assembly functions.
runtime_BeforeFork()
locked = true
if clone3 != nil {
pid, err1 = rawVforkSyscall(_SYS_clone3, uintptr(unsafe.Pointer(clone3)), unsafe.Sizeof(*clone3))
} else {
flags |= uintptr(SIGCHLD)
if runtime.GOARCH == "s390x" {
// On Linux/s390, the first two arguments of clone(2) are swapped.
pid, err1 = rawVforkSyscall(SYS_CLONE, 0, flags)
} else {
pid, err1 = rawVforkSyscall(SYS_CLONE, flags, 0)
}
}
if err1 != 0 || pid != 0 {
// If we're in the parent, we must return immediately
// so we're not in the same stack frame as the child.
// This can at most use the return PC, which the child
// will not modify, and the results of
// rawVforkSyscall, which must have been written after
// the child was replaced.
return
}
// Fork succeeded, now in child.
// Enable the "keep capabilities" flag to set ambient capabilities later.
if len(sys.AmbientCaps) > 0 {
_, _, err1 = RawSyscall6(SYS_PRCTL, PR_SET_KEEPCAPS, 1, 0, 0, 0, 0)
if err1 != 0 {
goto childerror
}
}
// Wait for User ID/Group ID mappings to be written.
if sys.UidMappings != nil || sys.GidMappings != nil {
if _, _, err1 = RawSyscall(SYS_CLOSE, uintptr(mapPipe[1]), 0, 0); err1 != 0 {
goto childerror
}
pid, _, err1 = RawSyscall(SYS_READ, uintptr(mapPipe[0]), uintptr(unsafe.Pointer(&err2)), unsafe.Sizeof(err2))
if err1 != 0 {
goto childerror
}
if pid != unsafe.Sizeof(err2) {
err1 = EINVAL
goto childerror
}
if err2 != 0 {
err1 = err2
goto childerror
}
}
// Session ID
if sys.Setsid {
_, _, err1 = RawSyscall(SYS_SETSID, 0, 0, 0)
if err1 != 0 {
goto childerror
}
}
// Set process group
if sys.Setpgid || sys.Foreground {
// Place child in process group.
_, _, err1 = RawSyscall(SYS_SETPGID, 0, uintptr(sys.Pgid), 0)
if err1 != 0 {
goto childerror
}
}
if sys.Foreground {
pgrp = int32(sys.Pgid)
if pgrp == 0 {
pid, _ = rawSyscallNoError(SYS_GETPID, 0, 0, 0)
pgrp = int32(pid)
}
// Place process group in foreground.
_, _, err1 = RawSyscall(SYS_IOCTL, uintptr(sys.Ctty), uintptr(TIOCSPGRP), uintptr(unsafe.Pointer(&pgrp)))
if err1 != 0 {
goto childerror
}
}
// Restore the signal mask. We do this after TIOCSPGRP to avoid
// having the kernel send a SIGTTOU signal to the process group.
runtime_AfterForkInChild()
// Unshare
if sys.Unshareflags != 0 {
_, _, err1 = RawSyscall(SYS_UNSHARE, sys.Unshareflags, 0, 0)
if err1 != 0 {
goto childerror
}
if sys.Unshareflags&CLONE_NEWUSER != 0 && sys.GidMappings != nil {
dirfd = int(_AT_FDCWD)
if fd1, _, err1 = RawSyscall6(SYS_OPENAT, uintptr(dirfd), uintptr(unsafe.Pointer(&psetgroups[0])), uintptr(O_WRONLY), 0, 0, 0); err1 != 0 {
goto childerror
}
pid, _, err1 = RawSyscall(SYS_WRITE, uintptr(fd1), uintptr(unsafe.Pointer(&setgroups[0])), uintptr(len(setgroups)))
if err1 != 0 {
goto childerror
}
if _, _, err1 = RawSyscall(SYS_CLOSE, uintptr(fd1), 0, 0); err1 != 0 {
goto childerror
}
if fd1, _, err1 = RawSyscall6(SYS_OPENAT, uintptr(dirfd), uintptr(unsafe.Pointer(&pgid[0])), uintptr(O_WRONLY), 0, 0, 0); err1 != 0 {
goto childerror
}
pid, _, err1 = RawSyscall(SYS_WRITE, uintptr(fd1), uintptr(unsafe.Pointer(&gidmap[0])), uintptr(len(gidmap)))
if err1 != 0 {
goto childerror
}
if _, _, err1 = RawSyscall(SYS_CLOSE, uintptr(fd1), 0, 0); err1 != 0 {
goto childerror
}
}
if sys.Unshareflags&CLONE_NEWUSER != 0 && sys.UidMappings != nil {
dirfd = int(_AT_FDCWD)
if fd1, _, err1 = RawSyscall6(SYS_OPENAT, uintptr(dirfd), uintptr(unsafe.Pointer(&puid[0])), uintptr(O_WRONLY), 0, 0, 0); err1 != 0 {
goto childerror
}
pid, _, err1 = RawSyscall(SYS_WRITE, uintptr(fd1), uintptr(unsafe.Pointer(&uidmap[0])), uintptr(len(uidmap)))
if err1 != 0 {
goto childerror
}
if _, _, err1 = RawSyscall(SYS_CLOSE, uintptr(fd1), 0, 0); err1 != 0 {
goto childerror
}
}
// The unshare system call in Linux doesn't unshare mount points
// mounted with --shared. Systemd mounts / with --shared. For a
// long discussion of the pros and cons of this see debian bug 739593.
// The Go model of unsharing is more like Plan 9, where you ask
// to unshare and the namespaces are unconditionally unshared.
// To make this model work we must further mark / as MS_PRIVATE.
// This is what the standard unshare command does.
if sys.Unshareflags&CLONE_NEWNS == CLONE_NEWNS {
_, _, err1 = RawSyscall6(SYS_MOUNT, uintptr(unsafe.Pointer(&none[0])), uintptr(unsafe.Pointer(&slash[0])), 0, MS_REC|MS_PRIVATE, 0, 0)
if err1 != 0 {
goto childerror
}
}
}
// Chroot
if chroot != nil {
_, _, err1 = RawSyscall(SYS_CHROOT, uintptr(unsafe.Pointer(chroot)), 0, 0)
if err1 != 0 {
goto childerror
}
}
// User and groups
if cred = sys.Credential; cred != nil {
ngroups = uintptr(len(cred.Groups))
groups = uintptr(0)
if ngroups > 0 {
groups = uintptr(unsafe.Pointer(&cred.Groups[0]))
}
if !(sys.GidMappings != nil && !sys.GidMappingsEnableSetgroups && ngroups == 0) && !cred.NoSetGroups {
_, _, err1 = RawSyscall(_SYS_setgroups, ngroups, groups, 0)
if err1 != 0 {
goto childerror
}
}
_, _, err1 = RawSyscall(sys_SETGID, uintptr(cred.Gid), 0, 0)
if err1 != 0 {
goto childerror
}
_, _, err1 = RawSyscall(sys_SETUID, uintptr(cred.Uid), 0, 0)
if err1 != 0 {
goto childerror
}
}
if len(sys.AmbientCaps) != 0 {
// Ambient capabilities were added in the 4.3 kernel,
// so it is safe to always use _LINUX_CAPABILITY_VERSION_3.
caps.hdr.version = _LINUX_CAPABILITY_VERSION_3
if _, _, err1 = RawSyscall(SYS_CAPGET, uintptr(unsafe.Pointer(&caps.hdr)), uintptr(unsafe.Pointer(&caps.data[0])), 0); err1 != 0 {
goto childerror
}
for _, c = range sys.AmbientCaps {
// Add the c capability to the permitted and inheritable capability mask,
// otherwise we will not be able to add it to the ambient capability mask.
caps.data[capToIndex(c)].permitted |= capToMask(c)
caps.data[capToIndex(c)].inheritable |= capToMask(c)
}
if _, _, err1 = RawSyscall(SYS_CAPSET, uintptr(unsafe.Pointer(&caps.hdr)), uintptr(unsafe.Pointer(&caps.data[0])), 0); err1 != 0 {
goto childerror
}
for _, c = range sys.AmbientCaps {
_, _, err1 = RawSyscall6(SYS_PRCTL, PR_CAP_AMBIENT, uintptr(PR_CAP_AMBIENT_RAISE), c, 0, 0, 0)
if err1 != 0 {
goto childerror
}
}
}
// Chdir
if dir != nil {
_, _, err1 = RawSyscall(SYS_CHDIR, uintptr(unsafe.Pointer(dir)), 0, 0)
if err1 != 0 {
goto childerror
}
}
// Parent death signal
if sys.Pdeathsig != 0 {
_, _, err1 = RawSyscall6(SYS_PRCTL, PR_SET_PDEATHSIG, uintptr(sys.Pdeathsig), 0, 0, 0, 0)
if err1 != 0 {
goto childerror
}
// Signal self if parent is already dead. This might cause a
// duplicate signal in rare cases, but it won't matter when
// using SIGKILL.
pid, _ = rawSyscallNoError(SYS_GETPPID, 0, 0, 0)
if pid != ppid {
pid, _ = rawSyscallNoError(SYS_GETPID, 0, 0, 0)
_, _, err1 = RawSyscall(SYS_KILL, pid, uintptr(sys.Pdeathsig), 0)
if err1 != 0 {
goto childerror
}
}
}
// Pass 1: look for fd[i] < i and move those up above len(fd)
// so that pass 2 won't stomp on an fd it needs later.
if pipe < nextfd {
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(pipe), uintptr(nextfd), O_CLOEXEC)
if err1 != 0 {
goto childerror
}
pipe = nextfd
nextfd++
}
for i = 0; i < len(fd); i++ {
if fd[i] >= 0 && fd[i] < i {
if nextfd == pipe { // don't stomp on pipe
nextfd++
}
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(fd[i]), uintptr(nextfd), O_CLOEXEC)
if err1 != 0 {
goto childerror
}
fd[i] = nextfd
nextfd++
}
}
// Pass 2: dup fd[i] down onto i.
for i = 0; i < len(fd); i++ {
if fd[i] == -1 {
RawSyscall(SYS_CLOSE, uintptr(i), 0, 0)
continue
}
if fd[i] == i {
// dup2(i, i) won't clear close-on-exec flag on Linux,
// probably not elsewhere either.
_, _, err1 = RawSyscall(fcntl64Syscall, uintptr(fd[i]), F_SETFD, 0)
if err1 != 0 {
goto childerror
}
continue
}
// The new fd is created NOT close-on-exec,
// which is exactly what we want.
_, _, err1 = RawSyscall(SYS_DUP3, uintptr(fd[i]), uintptr(i), 0)
if err1 != 0 {
goto childerror
}
}
// By convention, we don't close-on-exec the fds we are
// started with, so if len(fd) < 3, close 0, 1, 2 as needed.
// Programs that know they inherit fds >= 3 will need
// to set them close-on-exec.
for i = len(fd); i < 3; i++ {
RawSyscall(SYS_CLOSE, uintptr(i), 0, 0)
}
// Detach fd 0 from tty
if sys.Noctty {
_, _, err1 = RawSyscall(SYS_IOCTL, 0, uintptr(TIOCNOTTY), 0)
if err1 != 0 {
goto childerror
}
}
// Set the controlling TTY to Ctty
if sys.Setctty {
_, _, err1 = RawSyscall(SYS_IOCTL, uintptr(sys.Ctty), uintptr(TIOCSCTTY), 1)
if err1 != 0 {
goto childerror
}
}
// Restore original rlimit.
if rlimOK && rlim.Cur != 0 {
rawSetrlimit(RLIMIT_NOFILE, &rlim)
}
// Enable tracing if requested.
// Do this right before exec so that we don't unnecessarily trace the runtime
// setting up after the fork. See issue #21428.
if sys.Ptrace {
_, _, err1 = RawSyscall(SYS_PTRACE, uintptr(PTRACE_TRACEME), 0, 0)
if err1 != 0 {
goto childerror
}
}
// Time to exec.
_, _, err1 = RawSyscall(SYS_EXECVE,
uintptr(unsafe.Pointer(argv0)),
uintptr(unsafe.Pointer(&argv[0])),
uintptr(unsafe.Pointer(&envv[0])))
childerror:
// send error code on pipe
RawSyscall(SYS_WRITE, uintptr(pipe), uintptr(unsafe.Pointer(&err1)), unsafe.Sizeof(err1))
for {
RawSyscall(SYS_EXIT, 253, 0, 0)
}
*/
panic("todo: syscall.forkAndExecInChild1")
}
func formatIDMappings(idMap []SysProcIDMap) []byte {
/* TODO(xsw):
var data []byte
for _, im := range idMap {
data = append(data, itoa.Itoa(im.ContainerID)+" "+itoa.Itoa(im.HostID)+" "+itoa.Itoa(im.Size)+"\n"...)
}
return data
*/
panic("todo: syscall.formatIDMappings")
}
// writeIDMappings writes the user namespace User ID or Group ID mappings to the specified path.
func writeIDMappings(path string, idMap []SysProcIDMap) error {
/* TODO(xsw):
fd, err := Open(path, O_RDWR, 0)
if err != nil {
return err
}
if _, err := Write(fd, formatIDMappings(idMap)); err != nil {
Close(fd)
return err
}
if err := Close(fd); err != nil {
return err
}
return nil
*/
panic("todo: syscall.writeIDMappings")
}
// writeSetgroups writes to /proc/PID/setgroups "deny" if enable is false
// and "allow" if enable is true.
// This is needed since kernel 3.19, because you can't write gid_map without
// disabling setgroups() system call.
func writeSetgroups(pid int, enable bool) error {
/* TODO(xsw):
sgf := "/proc/" + itoa.Itoa(pid) + "/setgroups"
fd, err := Open(sgf, O_RDWR, 0)
if err != nil {
return err
}
var data []byte
if enable {
data = []byte("allow")
} else {
data = []byte("deny")
}
if _, err := Write(fd, data); err != nil {
Close(fd)
return err
}
return Close(fd)
*/
panic("todo: syscall.writeSetgroups")
}
// writeUidGidMappings writes User ID and Group ID mappings for user namespaces
// for a process and it is called from the parent process.
func writeUidGidMappings(pid int, sys *SysProcAttr) error {
/* TODO(xsw):
if sys.UidMappings != nil {
uidf := "/proc/" + itoa.Itoa(pid) + "/uid_map"
if err := writeIDMappings(uidf, sys.UidMappings); err != nil {
return err
}
}
if sys.GidMappings != nil {
// If the kernel is too old to support /proc/PID/setgroups, writeSetGroups will return ENOENT; this is OK.
if err := writeSetgroups(pid, sys.GidMappingsEnableSetgroups); err != nil && err != ENOENT {
return err
}
gidf := "/proc/" + itoa.Itoa(pid) + "/gid_map"
if err := writeIDMappings(gidf, sys.GidMappings); err != nil {
return err
}
}
return nil
*/
panic("todo: syscall.writeUidGidMappings")
}