forked from elves/elvish
/
main.go
274 lines (247 loc) · 7.01 KB
/
main.go
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// Elvish is an experimental Unix shell. It tries to incorporate a powerful
// programming language with an extensible, friendly user interface.
package main
// This package sets up the basic environment and calls the appropriate
// "subprogram", one of the daemon, the terminal interface, or the web
// interface.
import (
"errors"
"flag"
"fmt"
"log"
"os"
"path"
"runtime/pprof"
"strconv"
"syscall"
"time"
"github.com/elves/elvish/daemon"
"github.com/elves/elvish/daemon/api"
"github.com/elves/elvish/daemon/service"
"github.com/elves/elvish/eval"
"github.com/elves/elvish/eval/re"
"github.com/elves/elvish/shell"
"github.com/elves/elvish/store/storedefs"
"github.com/elves/elvish/util"
"github.com/elves/elvish/web"
)
// defaultPort is the default port on which the web interface runs. The number
// is chosen because it resembles "elvi".
const defaultWebPort = 3171
var logger = util.GetLogger("[main] ")
var (
// Flags handled in this package, or common to shell and daemon.
help = flag.Bool("help", false, "show usage help and quit")
logpath = flag.String("log", "", "a file to write debug log to")
cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
dbpath = flag.String("db", "", "path to the database")
sockpath = flag.String("sock", "", "path to the daemon socket")
isdaemon = flag.Bool("daemon", false, "run daemon instead of shell")
isweb = flag.Bool("web", false, "run backend of web interface")
webport = flag.Int("port", defaultWebPort, "the port of the web backend")
// Flags for shell and web.
cmd = flag.Bool("c", false, "take first argument as a command to execute")
// Flags for daemon.
forked = flag.Int("forked", 0, "how many times the daemon has forked")
binpath = flag.String("bin", "", "path to the elvish binary")
logpathprefix = flag.String("logprefix", "", "the prefix for the daemon log file")
)
func usage() {
fmt.Println("usage: elvish [flags] [script]")
fmt.Println("flags:")
flag.PrintDefaults()
}
func main() {
// This is needed for defers to be honored.
ret := 0
defer os.Exit(ret)
// Parse and check flags.
flag.Usage = usage
flag.Parse()
args := flag.Args()
if *help {
usage()
return
}
if *isdaemon && len(args) > 0 {
// The daemon takes no argument.
usage()
ret = 2
return
}
// Flags common to all sub-programs: log and CPU profile.
if *isdaemon {
if *forked == 2 && *logpathprefix != "" {
// Honor logpathprefix.
pid := syscall.Getpid()
err := util.SetOutputFile(*logpathprefix + strconv.Itoa(pid))
if err != nil {
fmt.Fprintln(os.Stderr, err)
}
} else {
util.SetOutputFile("/dev/stderr")
}
} else if *logpath != "" {
err := util.SetOutputFile(*logpath)
if err != nil {
fmt.Fprintln(os.Stderr, err)
}
}
if *cpuprofile != "" {
f, err := os.Create(*cpuprofile)
if err != nil {
log.Fatal(err)
}
pprof.StartCPUProfile(f)
defer pprof.StopCPUProfile()
}
// Pick a sub-program to run.
if *isdaemon {
d := daemon.Daemon{
Forked: *forked,
BinPath: *binpath,
DbPath: *dbpath,
SockPath: *sockpath,
LogPathPrefix: *logpathprefix,
}
ret = d.Main(service.Serve)
} else {
// Shell or web. Set up common runtime components.
ev, cl := initRuntime()
defer func() {
err := cl.Close()
if err != nil {
fmt.Fprintln(os.Stderr, "warning: failed to close connection to daemon:", err)
}
}()
if *isweb {
if *cmd {
fmt.Fprintln(os.Stderr, "-c -web not yet supported")
ret = 2
return
}
w := web.NewWeb(ev, *webport)
ret = w.Run(args)
} else {
sh := shell.NewShell(ev, cl, *cmd)
ret = sh.Run(args)
}
}
}
const (
daemonWaitOneLoop = 10 * time.Millisecond
daemonWaitLoops = 100
daemonWaitTotal = daemonWaitOneLoop * daemonWaitLoops
)
func initRuntime() (*eval.Evaler, *api.Client) {
var dataDir string
var err error
// Determine data directory.
dataDir, err = storedefs.EnsureDataDir()
if err != nil {
fmt.Fprintln(os.Stderr, "warning: cannot create data directory ~/.elvish")
} else {
if *dbpath == "" {
*dbpath = dataDir + "/db"
}
}
// Determine runtime directory.
runDir, err := getSecureRunDir()
if err != nil {
fmt.Fprintln(os.Stderr, "cannot get runtime dir /tmp/elvish-$uid, falling back to data dir ~/.elvish:", err)
runDir = dataDir
}
if *sockpath == "" {
*sockpath = runDir + "/sock"
}
toSpawn := &daemon.Daemon{
Forked: *forked,
BinPath: *binpath,
DbPath: *dbpath,
SockPath: *sockpath,
LogPathPrefix: runDir + "/daemon.log.",
}
var cl *api.Client
if *sockpath != "" && *dbpath != "" {
cl = api.NewClient(*sockpath)
_, statErr := os.Stat(*sockpath)
killed := false
if statErr == nil {
// Kill the daemon if it is outdated.
version, err := cl.Version()
if err != nil {
fmt.Fprintln(os.Stderr, "warning: socket exists but not responding version RPC:", err)
goto spawnDaemonEnd
}
logger.Printf("daemon serving version %d, want version %d", version, api.Version)
if version < api.Version {
pid, err := cl.Pid()
if err != nil {
fmt.Fprintln(os.Stderr, "warning: socket exists but not responding pid RPC:", err)
goto spawnDaemonEnd
}
logger.Printf("killing outdated daemon with pid %d", pid)
err = syscall.Kill(pid, syscall.SIGTERM)
if err != nil {
fmt.Fprintln(os.Stderr, "warning: failed to kill outdated daemon process:", err)
goto spawnDaemonEnd
}
logger.Println("killed outdated daemon")
killed = true
}
}
if os.IsNotExist(statErr) || killed {
logger.Println("socket does not exists, starting daemon")
err := toSpawn.Spawn()
if err != nil {
fmt.Fprintln(os.Stderr, "warning: cannot start daemon:", err)
} else {
logger.Println("started daemon")
}
for i := 0; i < daemonWaitLoops; i++ {
_, err := cl.Version()
if err == nil {
logger.Println("daemon online")
goto spawnDaemonEnd
} else if i == daemonWaitLoops-1 {
fmt.Fprintf(os.Stderr, "cannot connect to daemon after %v: %v\n", daemonWaitTotal, err)
cl = nil
goto spawnDaemonEnd
}
time.Sleep(daemonWaitOneLoop)
}
}
}
spawnDaemonEnd:
// TODO(xiaq): This information might belong somewhere else.
extraModules := map[string]eval.Namespace{
"re": re.Namespace(),
}
return eval.NewEvaler(cl, toSpawn, dataDir, extraModules), cl
}
var (
ErrBadOwner = errors.New("bad owner")
ErrBadPermission = errors.New("bad permission")
)
// getSecureRunDir stats /tmp/elvish-$uid, creating it if it doesn't yet exist,
// and return the directory name if it has the correct owner and permission.
func getSecureRunDir() (string, error) {
uid := syscall.Getuid()
runDir := path.Join(os.TempDir(), fmt.Sprintf("elvish-%d", uid))
err := os.MkdirAll(runDir, 0700)
if err != nil {
return "", fmt.Errorf("mkdir: %v", err)
}
var stat syscall.Stat_t
err = syscall.Stat(runDir, &stat)
if err != nil {
return "", fmt.Errorf("stat: %v", err)
}
if int(stat.Uid) != uid {
return "", ErrBadOwner
}
if stat.Mode&077 != 0 {
return "", ErrBadPermission
}
return runDir, err
}