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os, syscall: add ProcAttr type. Change StartProcess etc. to use it.

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The Windows code is untested.

R=rsc, gri, brainman, rsc1
CC=golang-dev
https://golang.org/cl/4253052
This commit is contained in:
Roger Peppe 2011-03-15 14:41:19 -04:00 • committed by Russ Cox
parent a34f1bbb22
commit aa55c05213
9 changed files with 115 additions and 54 deletions
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62
src/pkg/syscall/exec_unix.go
View file

@ -96,13 +96,16 @@ func SetNonblock(fd int, nonblocking bool) (errno int) {
// no rescheduling, no malloc calls, and no new stack segments.
// The calls to RawSyscall are okay because they are assembly
// functions that do not grow the stack.
func forkAndExecInChild(argv0 *byte, argv []*byte, envv []*byte, traceme bool, dir *byte, fd []int, pipe int) (pid int, err int) {
func forkAndExecInChild(argv0 *byte, argv, envv []*byte, dir *byte, attr *ProcAttr, pipe int) (pid int, err int) {
// Declare all variables at top in case any
// declarations require heap allocation (e.g., err1).
var r1, r2, err1 uintptr
var nextfd int
var i int
// guard against side effects of shuffling fds below.
fd := append([]int(nil), attr.Files...)
darwin := OS == "darwin"
// About to call fork.
@ -128,13 +131,21 @@ func forkAndExecInChild(argv0 *byte, argv []*byte, envv []*byte, traceme bool, d
// Fork succeeded, now in child.
// Enable tracing if requested.
if traceme {
if attr.Ptrace {
_, _, err1 = RawSyscall(SYS_PTRACE, uintptr(PTRACE_TRACEME), 0, 0)
if err1 != 0 {
goto childerror
}
}
// Session ID
if attr.Setsid {
_, _, err1 = RawSyscall(SYS_SETSID, 0, 0, 0)
if err1 != 0 {
goto childerror
}
}
// Chdir
if dir != nil {
_, _, err1 = RawSyscall(SYS_CHDIR, uintptr(unsafe.Pointer(dir)), 0, 0)
@ -220,28 +231,44 @@ childerror:
panic("unreached")
}
func forkExec(argv0 string, argv []string, envv []string, traceme bool, dir string, fd []int) (pid int, err int) {
type ProcAttr struct {
Setsid bool // Create session.
Ptrace bool // Enable tracing.
Dir string // Current working directory.
Env []string // Environment.
Files []int // File descriptors.
}
var zeroAttributes ProcAttr
func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err int) {
var p [2]int
var n int
var err1 uintptr
var wstatus WaitStatus
if attr == nil {
attr = &zeroAttributes
}
p[0] = -1
p[1] = -1
// Convert args to C form.
argv0p := StringBytePtr(argv0)
argvp := StringArrayPtr(argv)
envvp := StringArrayPtr(envv)
var dirp *byte
if len(dir) > 0 {
dirp = StringBytePtr(dir)
}
envvp := StringArrayPtr(attr.Env)
if OS == "freebsd" && len(argv[0]) > len(argv0) {
argvp[0] = argv0p
}
var dir *byte
if attr.Dir != "" {
dir = StringBytePtr(attr.Dir)
}
// Acquire the fork lock so that no other threads
// create new fds that are not yet close-on-exec
// before we fork.
@ -259,7 +286,7 @@ func forkExec(argv0 string, argv []string, envv []string, traceme bool, dir stri
}
// Kick off child.
pid, err = forkAndExecInChild(argv0p, argvp, envvp, traceme, dirp, fd, p[1])
pid, err = forkAndExecInChild(argv0p, argvp, envvp, dir, attr, p[1])
if err != 0 {
error:
if p[0] >= 0 {
@ -297,13 +324,14 @@ func forkExec(argv0 string, argv []string, envv []string, traceme bool, dir stri
}
// Combination of fork and exec, careful to be thread safe.
func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []int) (pid int, err int) {
return forkExec(argv0, argv, envv, false, dir, fd)
func ForkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err int) {
return forkExec(argv0, argv, attr)
}
// PtraceForkExec is like ForkExec, but starts the child in a traced state.
func PtraceForkExec(argv0 string, argv []string, envv []string, dir string, fd []int) (pid int, err int) {
return forkExec(argv0, argv, envv, true, dir, fd)
// StartProcess wraps ForkExec for package os.
func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid, handle int, err int) {
pid, err = forkExec(argv0, argv, attr)
return pid, 0, err
}
// Ordinary exec.
@ -314,9 +342,3 @@ func Exec(argv0 string, argv []string, envv []string) (err int) {
uintptr(unsafe.Pointer(&StringArrayPtr(envv)[0])))
return int(err1)
}
// StartProcess wraps ForkExec for package os.
func StartProcess(argv0 string, argv []string, envv []string, dir string, fd []int) (pid, handle int, err int) {
pid, err = forkExec(argv0, argv, envv, false, dir, fd)
return pid, 0, err
}