// +build linux

package main

import (
	"fmt"
	"strconv"
	"strings"
	"syscall"

	"golang.org/x/sys/unix"

	"github.com/urfave/cli"
)

var signalMap = map[string]syscall.Signal{
	"ABRT":   unix.SIGABRT,
	"ALRM":   unix.SIGALRM,
	"BUS":    unix.SIGBUS,
	"CHLD":   unix.SIGCHLD,
	"CLD":    unix.SIGCLD,
	"CONT":   unix.SIGCONT,
	"FPE":    unix.SIGFPE,
	"HUP":    unix.SIGHUP,
	"ILL":    unix.SIGILL,
	"INT":    unix.SIGINT,
	"IO":     unix.SIGIO,
	"IOT":    unix.SIGIOT,
	"KILL":   unix.SIGKILL,
	"PIPE":   unix.SIGPIPE,
	"POLL":   unix.SIGPOLL,
	"PROF":   unix.SIGPROF,
	"PWR":    unix.SIGPWR,
	"QUIT":   unix.SIGQUIT,
	"SEGV":   unix.SIGSEGV,
	"STKFLT": unix.SIGSTKFLT,
	"STOP":   unix.SIGSTOP,
	"SYS":    unix.SIGSYS,
	"TERM":   unix.SIGTERM,
	"TRAP":   unix.SIGTRAP,
	"TSTP":   unix.SIGTSTP,
	"TTIN":   unix.SIGTTIN,
	"TTOU":   unix.SIGTTOU,
	"UNUSED": unix.SIGUNUSED,
	"URG":    unix.SIGURG,
	"USR1":   unix.SIGUSR1,
	"USR2":   unix.SIGUSR2,
	"VTALRM": unix.SIGVTALRM,
	"WINCH":  unix.SIGWINCH,
	"XCPU":   unix.SIGXCPU,
	"XFSZ":   unix.SIGXFSZ,
}

var killCommand = cli.Command{
	Name:  "kill",
	Usage: "kill sends the specified signal (default: SIGTERM) to the container's init process",
	ArgsUsage: `<container-id> [signal]

Where "<container-id>" is the name for the instance of the container and
"[signal]" is the signal to be sent to the init process.

EXAMPLE:
For example, if the container id is "ubuntu01" the following will send a "KILL"
signal to the init process of the "ubuntu01" container:
	 
       # runc kill ubuntu01 KILL`,
	Flags: []cli.Flag{
		cli.BoolFlag{
			Name:  "all, a",
			Usage: "send the specified signal to all processes inside the container",
		},
	},
	Action: func(context *cli.Context) error {
		if err := checkArgs(context, 1, minArgs); err != nil {
			return err
		}
		if err := checkArgs(context, 2, maxArgs); err != nil {
			return err
		}
		container, err := getContainer(context)
		if err != nil {
			return err
		}

		sigstr := context.Args().Get(1)
		if sigstr == "" {
			sigstr = "SIGTERM"
		}

		signal, err := parseSignal(sigstr)
		if err != nil {
			return err
		}
		if err := container.Signal(signal, context.Bool("all")); err != nil {
			return err
		}
		return nil
	},
}

func parseSignal(rawSignal string) (syscall.Signal, error) {
	s, err := strconv.Atoi(rawSignal)
	if err == nil {
		sig := syscall.Signal(s)
		for _, msig := range signalMap {
			if sig == msig {
				return sig, nil
			}
		}
		return -1, fmt.Errorf("unknown signal %q", rawSignal)
	}
	signal, ok := signalMap[strings.TrimPrefix(strings.ToUpper(rawSignal), "SIG")]
	if !ok {
		return -1, fmt.Errorf("unknown signal %q", rawSignal)
	}
	return signal, nil
}