| // 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. |
| |
| // +build linux |
| |
| package syscall |
| |
| import ( |
| "runtime" |
| "unsafe" |
| ) |
| |
| // 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 bool // Set process group ID to Pgid, or, if Pgid == 0, to new pid. |
| Setctty bool // Set controlling terminal to fd Ctty (only meaningful if Setsid is set) |
| Noctty bool // Detach fd 0 from controlling terminal |
| Ctty int // Controlling TTY fd |
| Foreground bool // Place child's process group in foreground. (Implies Setpgid. Uses Ctty as fd of controlling TTY) |
| Pgid int // Child's process group ID if Setpgid. |
| Pdeathsig Signal // Signal that the process will get when its parent dies (Linux only) |
| 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) |
| } |
| |
| var ( |
| none = [...]byte{'n', 'o', 'n', 'e', 0} |
| slash = [...]byte{'/', 0} |
| ) |
| |
| // 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) { |
| // Set up and fork. This returns immediately in the parent or |
| // if there's an error. |
| r1, err1, p, locked := forkAndExecInChild1(argv0, argv, envv, chroot, dir, attr, sys, pipe) |
| if locked { |
| runtime_AfterFork() |
| } |
| if err1 != 0 { |
| return 0, err1 |
| } |
| |
| // parent; return PID |
| pid = int(r1) |
| |
| if sys.UidMappings != nil || sys.GidMappings != nil { |
| Close(p[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(p[1]), uintptr(unsafe.Pointer(&err2)), unsafe.Sizeof(err2)) |
| Close(p[1]) |
| } |
| |
| return pid, 0 |
| } |
| |
| 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) } |
| |
| // 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 |
| func forkAndExecInChild1(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr *ProcAttr, sys *SysProcAttr, pipe int) (r1 uintptr, err1 Errno, p [2]int, locked bool) { |
| // 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., err1). |
| var ( |
| err2 Errno |
| nextfd int |
| i int |
| caps caps |
| fd1 uintptr |
| puid, psetgroups, pgid []byte |
| uidmap, setgroups, gidmap []byte |
| ) |
| |
| 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(p[:]); err != nil { |
| err1 = err.(Errno) |
| return |
| } |
| } |
| |
| hasRawVforkSyscall := runtime.GOARCH == "amd64" || runtime.GOARCH == "ppc64" || runtime.GOARCH == "s390x" || runtime.GOARCH == "arm64" |
| |
| // About to call fork. |
| // No more allocation or calls of non-assembly functions. |
| runtime_BeforeFork() |
| locked = true |
| switch { |
| case hasRawVforkSyscall && (sys.Cloneflags&CLONE_NEWUSER == 0 && sys.Unshareflags&CLONE_NEWUSER == 0): |
| r1, err1 = rawVforkSyscall(SYS_CLONE, uintptr(SIGCHLD|CLONE_VFORK|CLONE_VM)|sys.Cloneflags) |
| case runtime.GOARCH == "s390x": |
| r1, _, err1 = RawSyscall6(SYS_CLONE, 0, uintptr(SIGCHLD)|sys.Cloneflags, 0, 0, 0, 0) |
| default: |
| r1, _, err1 = RawSyscall6(SYS_CLONE, uintptr(SIGCHLD)|sys.Cloneflags, 0, 0, 0, 0, 0) |
| } |
| if err1 != 0 || r1 != 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. |
| |
| runtime_AfterForkInChild() |
| |
| // 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(p[1]), 0, 0); err1 != 0 { |
| goto childerror |
| } |
| r1, _, err1 = RawSyscall(SYS_READ, uintptr(p[0]), uintptr(unsafe.Pointer(&err2)), unsafe.Sizeof(err2)) |
| if err1 != 0 { |
| goto childerror |
| } |
| if r1 != 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 { |
| r1, _ = rawSyscallNoError(SYS_GETPID, 0, 0, 0) |
| |
| pgrp = int32(r1) |
| } |
| |
| // Place process group in foreground. |
| _, _, err1 = RawSyscall(SYS_IOCTL, uintptr(sys.Ctty), uintptr(TIOCSPGRP), uintptr(unsafe.Pointer(&pgrp))) |
| if err1 != 0 { |
| goto childerror |
| } |
| } |
| |
| // 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 |
| } |
| r1, _, 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 |
| } |
| r1, _, 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 |
| } |
| r1, _, 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. |
| r1, _ = rawSyscallNoError(SYS_GETPPID, 0, 0, 0) |
| if r1 != 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_dup, uintptr(pipe), uintptr(nextfd), 0) |
| if err1 != 0 { |
| goto childerror |
| } |
| RawSyscall(SYS_FCNTL, uintptr(nextfd), F_SETFD, FD_CLOEXEC) |
| pipe = nextfd |
| nextfd++ |
| } |
| for i = 0; i < len(fd); i++ { |
| if fd[i] >= 0 && fd[i] < int(i) { |
| if nextfd == pipe { // don't stomp on pipe |
| nextfd++ |
| } |
| _, _, err1 = RawSyscall(_SYS_dup, uintptr(fd[i]), uintptr(nextfd), 0) |
| if err1 != 0 { |
| goto childerror |
| } |
| RawSyscall(SYS_FCNTL, uintptr(nextfd), F_SETFD, FD_CLOEXEC) |
| 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] == int(i) { |
| // dup2(i, i) won't clear close-on-exec flag on Linux, |
| // probably not elsewhere either. |
| _, _, err1 = RawSyscall(SYS_FCNTL, 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_dup, 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 |
| } |
| } |
| |
| // 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) |
| } |
| } |
| |
| // Try to open a pipe with O_CLOEXEC set on both file descriptors. |
| func forkExecPipe(p []int) (err error) { |
| err = Pipe2(p, O_CLOEXEC) |
| // pipe2 was added in 2.6.27 and our minimum requirement is 2.6.23, so it |
| // might not be implemented. |
| if err == ENOSYS { |
| if err = Pipe(p); err != nil { |
| return |
| } |
| if _, err = fcntl(p[0], F_SETFD, FD_CLOEXEC); err != nil { |
| return |
| } |
| _, err = fcntl(p[1], F_SETFD, FD_CLOEXEC) |
| } |
| return |
| } |
| |
| func formatIDMappings(idMap []SysProcIDMap) []byte { |
| var data []byte |
| for _, im := range idMap { |
| data = append(data, []byte(itoa(im.ContainerID)+" "+itoa(im.HostID)+" "+itoa(im.Size)+"\n")...) |
| } |
| return data |
| } |
| |
| // writeIDMappings writes the user namespace User ID or Group ID mappings to the specified path. |
| func writeIDMappings(path string, idMap []SysProcIDMap) error { |
| 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 |
| } |
| |
| // 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 { |
| sgf := "/proc/" + 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) |
| } |
| |
| // 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 { |
| if sys.UidMappings != nil { |
| uidf := "/proc/" + 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(pid) + "/gid_map" |
| if err := writeIDMappings(gidf, sys.GidMappings); err != nil { |
| return err |
| } |
| } |
| |
| return nil |
| } |
