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child_process.zig
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child_process.zig
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const std = @import("std.zig");
const cstr = std.cstr;
const unicode = std.unicode;
const io = std.io;
const fs = std.fs;
const os = std.os;
const process = std.process;
const File = std.fs.File;
const windows = os.windows;
const mem = std.mem;
const debug = std.debug;
const BufMap = std.BufMap;
const ArrayListSentineled = std.ArrayListSentineled;
const builtin = @import("builtin");
const Os = builtin.Os;
const TailQueue = std.TailQueue;
const maxInt = std.math.maxInt;
pub const ChildProcess = struct {
pid: if (builtin.os.tag == .windows) void else i32,
handle: if (builtin.os.tag == .windows) windows.HANDLE else void,
thread_handle: if (builtin.os.tag == .windows) windows.HANDLE else void,
allocator: *mem.Allocator,
stdin: ?File,
stdout: ?File,
stderr: ?File,
term: ?(SpawnError!Term),
argv: []const []const u8,
/// Leave as null to use the current env map using the supplied allocator.
env_map: ?*const BufMap,
stdin_behavior: StdIo,
stdout_behavior: StdIo,
stderr_behavior: StdIo,
/// Set to change the user id when spawning the child process.
uid: if (builtin.os.tag == .windows) void else ?u32,
/// Set to change the group id when spawning the child process.
gid: if (builtin.os.tag == .windows) void else ?u32,
/// Set to change the current working directory when spawning the child process.
cwd: ?[]const u8,
/// Set to change the current working directory when spawning the child process.
/// This is not yet implemented for Windows. See https://github.com/ziglang/zig/issues/5190
/// Once that is done, `cwd` will be deprecated in favor of this field.
cwd_dir: ?fs.Dir = null,
err_pipe: if (builtin.os.tag == .windows) void else [2]os.fd_t,
expand_arg0: Arg0Expand,
pub const Arg0Expand = os.Arg0Expand;
pub const SpawnError = error{
OutOfMemory,
/// POSIX-only. `StdIo.Ignore` was selected and opening `/dev/null` returned ENODEV.
NoDevice,
/// Windows-only. One of:
/// * `cwd` was provided and it could not be re-encoded into UTF16LE, or
/// * The `PATH` or `PATHEXT` environment variable contained invalid UTF-8.
InvalidUtf8,
/// Windows-only. `cwd` was provided, but the path did not exist when spawning the child process.
CurrentWorkingDirectoryUnlinked,
} || os.ExecveError || os.SetIdError || os.ChangeCurDirError || windows.CreateProcessError || windows.WaitForSingleObjectError;
pub const Term = union(enum) {
Exited: u32,
Signal: u32,
Stopped: u32,
Unknown: u32,
};
pub const StdIo = enum {
Inherit,
Ignore,
Pipe,
Close,
};
/// First argument in argv is the executable.
/// On success must call deinit.
pub fn init(argv: []const []const u8, allocator: *mem.Allocator) !*ChildProcess {
const child = try allocator.create(ChildProcess);
child.* = ChildProcess{
.allocator = allocator,
.argv = argv,
.pid = undefined,
.handle = undefined,
.thread_handle = undefined,
.err_pipe = undefined,
.term = null,
.env_map = null,
.cwd = null,
.uid = if (builtin.os.tag == .windows) {} else null,
.gid = if (builtin.os.tag == .windows) {} else null,
.stdin = null,
.stdout = null,
.stderr = null,
.stdin_behavior = StdIo.Inherit,
.stdout_behavior = StdIo.Inherit,
.stderr_behavior = StdIo.Inherit,
.expand_arg0 = .no_expand,
};
errdefer allocator.destroy(child);
return child;
}
pub fn setUserName(self: *ChildProcess, name: []const u8) !void {
const user_info = try os.getUserInfo(name);
self.uid = user_info.uid;
self.gid = user_info.gid;
}
/// On success must call `kill` or `wait`.
pub fn spawn(self: *ChildProcess) SpawnError!void {
if (builtin.os.tag == .windows) {
return self.spawnWindows();
} else {
return self.spawnPosix();
}
}
pub fn spawnAndWait(self: *ChildProcess) SpawnError!Term {
try self.spawn();
return self.wait();
}
/// Forcibly terminates child process and then cleans up all resources.
pub fn kill(self: *ChildProcess) !Term {
if (builtin.os.tag == .windows) {
return self.killWindows(1);
} else {
return self.killPosix();
}
}
pub fn killWindows(self: *ChildProcess, exit_code: windows.UINT) !Term {
if (self.term) |term| {
self.cleanupStreams();
return term;
}
try windows.TerminateProcess(self.handle, exit_code);
try self.waitUnwrappedWindows();
return self.term.?;
}
pub fn killPosix(self: *ChildProcess) !Term {
if (self.term) |term| {
self.cleanupStreams();
return term;
}
try os.kill(self.pid, os.SIGTERM);
self.waitUnwrapped();
return self.term.?;
}
/// Blocks until child process terminates and then cleans up all resources.
pub fn wait(self: *ChildProcess) !Term {
if (builtin.os.tag == .windows) {
return self.waitWindows();
} else {
return self.waitPosix();
}
}
pub const ExecResult = struct {
term: Term,
stdout: []u8,
stderr: []u8,
};
pub const exec2 = @compileError("deprecated: exec2 is renamed to exec");
/// Spawns a child process, waits for it, collecting stdout and stderr, and then returns.
/// If it succeeds, the caller owns result.stdout and result.stderr memory.
pub fn exec(args: struct {
allocator: *mem.Allocator,
argv: []const []const u8,
cwd: ?[]const u8 = null,
cwd_dir: ?fs.Dir = null,
env_map: ?*const BufMap = null,
max_output_bytes: usize = 50 * 1024,
expand_arg0: Arg0Expand = .no_expand,
}) !ExecResult {
const child = try ChildProcess.init(args.argv, args.allocator);
defer child.deinit();
child.stdin_behavior = .Ignore;
child.stdout_behavior = .Pipe;
child.stderr_behavior = .Pipe;
child.cwd = args.cwd;
child.cwd_dir = args.cwd_dir;
child.env_map = args.env_map;
child.expand_arg0 = args.expand_arg0;
try child.spawn();
const stdout_in = child.stdout.?.inStream();
const stderr_in = child.stderr.?.inStream();
// TODO need to poll to read these streams to prevent a deadlock (or rely on evented I/O).
const stdout = try stdout_in.readAllAlloc(args.allocator, args.max_output_bytes);
errdefer args.allocator.free(stdout);
const stderr = try stderr_in.readAllAlloc(args.allocator, args.max_output_bytes);
errdefer args.allocator.free(stderr);
return ExecResult{
.term = try child.wait(),
.stdout = stdout,
.stderr = stderr,
};
}
fn waitWindows(self: *ChildProcess) !Term {
if (self.term) |term| {
self.cleanupStreams();
return term;
}
try self.waitUnwrappedWindows();
return self.term.?;
}
fn waitPosix(self: *ChildProcess) !Term {
if (self.term) |term| {
self.cleanupStreams();
return term;
}
self.waitUnwrapped();
return self.term.?;
}
pub fn deinit(self: *ChildProcess) void {
self.allocator.destroy(self);
}
fn waitUnwrappedWindows(self: *ChildProcess) !void {
const result = windows.WaitForSingleObjectEx(self.handle, windows.INFINITE, false);
self.term = @as(SpawnError!Term, x: {
var exit_code: windows.DWORD = undefined;
if (windows.kernel32.GetExitCodeProcess(self.handle, &exit_code) == 0) {
break :x Term{ .Unknown = 0 };
} else {
break :x Term{ .Exited = exit_code };
}
});
os.close(self.handle);
os.close(self.thread_handle);
self.cleanupStreams();
return result;
}
fn waitUnwrapped(self: *ChildProcess) void {
const status = os.waitpid(self.pid, 0);
self.cleanupStreams();
self.handleWaitResult(status);
}
fn handleWaitResult(self: *ChildProcess, status: u32) void {
// TODO https://github.com/ziglang/zig/issues/3190
var term = self.cleanupAfterWait(status);
self.term = term;
}
fn cleanupStreams(self: *ChildProcess) void {
if (self.stdin) |*stdin| {
stdin.close();
self.stdin = null;
}
if (self.stdout) |*stdout| {
stdout.close();
self.stdout = null;
}
if (self.stderr) |*stderr| {
stderr.close();
self.stderr = null;
}
}
fn cleanupAfterWait(self: *ChildProcess, status: u32) !Term {
defer destroyPipe(self.err_pipe);
if (builtin.os.tag == .linux) {
var fd = [1]std.os.pollfd{std.os.pollfd{
.fd = self.err_pipe[0],
.events = std.os.POLLIN,
.revents = undefined,
}};
// Check if the eventfd buffer stores a non-zero value by polling
// it, that's the error code returned by the child process.
_ = std.os.poll(&fd, 0) catch unreachable;
// According to eventfd(2) the descriptro is readable if the counter
// has a value greater than 0
if ((fd[0].revents & std.os.POLLIN) != 0) {
const err_int = try readIntFd(self.err_pipe[0]);
return @errSetCast(SpawnError, @intToError(err_int));
}
} else {
// Write maxInt(ErrInt) to the write end of the err_pipe. This is after
// waitpid, so this write is guaranteed to be after the child
// pid potentially wrote an error. This way we can do a blocking
// read on the error pipe and either get maxInt(ErrInt) (no error) or
// an error code.
try writeIntFd(self.err_pipe[1], maxInt(ErrInt));
const err_int = try readIntFd(self.err_pipe[0]);
// Here we potentially return the fork child's error from the parent
// pid.
if (err_int != maxInt(ErrInt)) {
return @errSetCast(SpawnError, @intToError(err_int));
}
}
return statusToTerm(status);
}
fn statusToTerm(status: u32) Term {
return if (os.WIFEXITED(status))
Term{ .Exited = os.WEXITSTATUS(status) }
else if (os.WIFSIGNALED(status))
Term{ .Signal = os.WTERMSIG(status) }
else if (os.WIFSTOPPED(status))
Term{ .Stopped = os.WSTOPSIG(status) }
else
Term{ .Unknown = status };
}
fn spawnPosix(self: *ChildProcess) SpawnError!void {
const pipe_flags = if (io.is_async) os.O_NONBLOCK else 0;
const stdin_pipe = if (self.stdin_behavior == StdIo.Pipe) try os.pipe2(pipe_flags) else undefined;
errdefer if (self.stdin_behavior == StdIo.Pipe) {
destroyPipe(stdin_pipe);
};
const stdout_pipe = if (self.stdout_behavior == StdIo.Pipe) try os.pipe2(pipe_flags) else undefined;
errdefer if (self.stdout_behavior == StdIo.Pipe) {
destroyPipe(stdout_pipe);
};
const stderr_pipe = if (self.stderr_behavior == StdIo.Pipe) try os.pipe2(pipe_flags) else undefined;
errdefer if (self.stderr_behavior == StdIo.Pipe) {
destroyPipe(stderr_pipe);
};
const any_ignore = (self.stdin_behavior == StdIo.Ignore or self.stdout_behavior == StdIo.Ignore or self.stderr_behavior == StdIo.Ignore);
const dev_null_fd = if (any_ignore)
os.openZ("/dev/null", os.O_RDWR, 0) catch |err| switch (err) {
error.PathAlreadyExists => unreachable,
error.NoSpaceLeft => unreachable,
error.FileTooBig => unreachable,
error.DeviceBusy => unreachable,
error.FileLocksNotSupported => unreachable,
else => |e| return e,
}
else
undefined;
defer {
if (any_ignore) os.close(dev_null_fd);
}
var env_map_owned: BufMap = undefined;
var we_own_env_map: bool = undefined;
const env_map = if (self.env_map) |env_map| x: {
we_own_env_map = false;
break :x env_map;
} else x: {
we_own_env_map = true;
env_map_owned = try process.getEnvMap(self.allocator);
break :x &env_map_owned;
};
defer {
if (we_own_env_map) env_map_owned.deinit();
}
// This pipe is used to communicate errors between the time of fork
// and execve from the child process to the parent process.
const err_pipe = blk: {
if (builtin.os.tag == .linux) {
const fd = try os.eventfd(0, 0);
// There's no distinction between the readable and the writeable
// end with eventfd
break :blk [2]os.fd_t{ fd, fd };
} else {
break :blk try os.pipe();
}
};
errdefer destroyPipe(err_pipe);
const pid_result = try os.fork();
if (pid_result == 0) {
// we are the child
setUpChildIo(self.stdin_behavior, stdin_pipe[0], os.STDIN_FILENO, dev_null_fd) catch |err| forkChildErrReport(err_pipe[1], err);
setUpChildIo(self.stdout_behavior, stdout_pipe[1], os.STDOUT_FILENO, dev_null_fd) catch |err| forkChildErrReport(err_pipe[1], err);
setUpChildIo(self.stderr_behavior, stderr_pipe[1], os.STDERR_FILENO, dev_null_fd) catch |err| forkChildErrReport(err_pipe[1], err);
if (self.stdin_behavior == .Pipe) {
os.close(stdin_pipe[0]);
os.close(stdin_pipe[1]);
}
if (self.stdout_behavior == .Pipe) {
os.close(stdout_pipe[0]);
os.close(stdout_pipe[1]);
}
if (self.stderr_behavior == .Pipe) {
os.close(stderr_pipe[0]);
os.close(stderr_pipe[1]);
}
if (self.cwd_dir) |cwd| {
os.fchdir(cwd.fd) catch |err| forkChildErrReport(err_pipe[1], err);
} else if (self.cwd) |cwd| {
os.chdir(cwd) catch |err| forkChildErrReport(err_pipe[1], err);
}
if (self.gid) |gid| {
os.setregid(gid, gid) catch |err| forkChildErrReport(err_pipe[1], err);
}
if (self.uid) |uid| {
os.setreuid(uid, uid) catch |err| forkChildErrReport(err_pipe[1], err);
}
const err = os.execvpe_expandArg0(self.allocator, self.expand_arg0, self.argv, env_map);
forkChildErrReport(err_pipe[1], err);
}
// we are the parent
const pid = @intCast(i32, pid_result);
if (self.stdin_behavior == StdIo.Pipe) {
self.stdin = File{ .handle = stdin_pipe[1] };
} else {
self.stdin = null;
}
if (self.stdout_behavior == StdIo.Pipe) {
self.stdout = File{ .handle = stdout_pipe[0] };
} else {
self.stdout = null;
}
if (self.stderr_behavior == StdIo.Pipe) {
self.stderr = File{ .handle = stderr_pipe[0] };
} else {
self.stderr = null;
}
self.pid = pid;
self.err_pipe = err_pipe;
self.term = null;
if (self.stdin_behavior == StdIo.Pipe) {
os.close(stdin_pipe[0]);
}
if (self.stdout_behavior == StdIo.Pipe) {
os.close(stdout_pipe[1]);
}
if (self.stderr_behavior == StdIo.Pipe) {
os.close(stderr_pipe[1]);
}
}
fn spawnWindows(self: *ChildProcess) SpawnError!void {
const saAttr = windows.SECURITY_ATTRIBUTES{
.nLength = @sizeOf(windows.SECURITY_ATTRIBUTES),
.bInheritHandle = windows.TRUE,
.lpSecurityDescriptor = null,
};
const any_ignore = (self.stdin_behavior == StdIo.Ignore or self.stdout_behavior == StdIo.Ignore or self.stderr_behavior == StdIo.Ignore);
// TODO use CreateFileW here since we are using a string literal for the path
const nul_handle = if (any_ignore)
windows.CreateFile(
"NUL",
windows.GENERIC_READ,
windows.FILE_SHARE_READ,
null,
windows.OPEN_EXISTING,
windows.FILE_ATTRIBUTE_NORMAL,
null,
) catch |err| switch (err) {
error.SharingViolation => unreachable, // not possible for "NUL"
error.PathAlreadyExists => unreachable, // not possible for "NUL"
error.PipeBusy => unreachable, // not possible for "NUL"
error.InvalidUtf8 => unreachable, // not possible for "NUL"
error.BadPathName => unreachable, // not possible for "NUL"
error.FileNotFound => unreachable, // not possible for "NUL"
error.AccessDenied => unreachable, // not possible for "NUL"
error.NameTooLong => unreachable, // not possible for "NUL"
else => |e| return e,
}
else
undefined;
defer {
if (any_ignore) os.close(nul_handle);
}
if (any_ignore) {
try windows.SetHandleInformation(nul_handle, windows.HANDLE_FLAG_INHERIT, 0);
}
var g_hChildStd_IN_Rd: ?windows.HANDLE = null;
var g_hChildStd_IN_Wr: ?windows.HANDLE = null;
switch (self.stdin_behavior) {
StdIo.Pipe => {
try windowsMakePipeIn(&g_hChildStd_IN_Rd, &g_hChildStd_IN_Wr, &saAttr);
},
StdIo.Ignore => {
g_hChildStd_IN_Rd = nul_handle;
},
StdIo.Inherit => {
g_hChildStd_IN_Rd = windows.GetStdHandle(windows.STD_INPUT_HANDLE) catch null;
},
StdIo.Close => {
g_hChildStd_IN_Rd = null;
},
}
errdefer if (self.stdin_behavior == StdIo.Pipe) {
windowsDestroyPipe(g_hChildStd_IN_Rd, g_hChildStd_IN_Wr);
};
var g_hChildStd_OUT_Rd: ?windows.HANDLE = null;
var g_hChildStd_OUT_Wr: ?windows.HANDLE = null;
switch (self.stdout_behavior) {
StdIo.Pipe => {
try windowsMakePipeOut(&g_hChildStd_OUT_Rd, &g_hChildStd_OUT_Wr, &saAttr);
},
StdIo.Ignore => {
g_hChildStd_OUT_Wr = nul_handle;
},
StdIo.Inherit => {
g_hChildStd_OUT_Wr = windows.GetStdHandle(windows.STD_OUTPUT_HANDLE) catch null;
},
StdIo.Close => {
g_hChildStd_OUT_Wr = null;
},
}
errdefer if (self.stdin_behavior == StdIo.Pipe) {
windowsDestroyPipe(g_hChildStd_OUT_Rd, g_hChildStd_OUT_Wr);
};
var g_hChildStd_ERR_Rd: ?windows.HANDLE = null;
var g_hChildStd_ERR_Wr: ?windows.HANDLE = null;
switch (self.stderr_behavior) {
StdIo.Pipe => {
try windowsMakePipeOut(&g_hChildStd_ERR_Rd, &g_hChildStd_ERR_Wr, &saAttr);
},
StdIo.Ignore => {
g_hChildStd_ERR_Wr = nul_handle;
},
StdIo.Inherit => {
g_hChildStd_ERR_Wr = windows.GetStdHandle(windows.STD_ERROR_HANDLE) catch null;
},
StdIo.Close => {
g_hChildStd_ERR_Wr = null;
},
}
errdefer if (self.stdin_behavior == StdIo.Pipe) {
windowsDestroyPipe(g_hChildStd_ERR_Rd, g_hChildStd_ERR_Wr);
};
const cmd_line = try windowsCreateCommandLine(self.allocator, self.argv);
defer self.allocator.free(cmd_line);
var siStartInfo = windows.STARTUPINFOW{
.cb = @sizeOf(windows.STARTUPINFOW),
.hStdError = g_hChildStd_ERR_Wr,
.hStdOutput = g_hChildStd_OUT_Wr,
.hStdInput = g_hChildStd_IN_Rd,
.dwFlags = windows.STARTF_USESTDHANDLES,
.lpReserved = null,
.lpDesktop = null,
.lpTitle = null,
.dwX = 0,
.dwY = 0,
.dwXSize = 0,
.dwYSize = 0,
.dwXCountChars = 0,
.dwYCountChars = 0,
.dwFillAttribute = 0,
.wShowWindow = 0,
.cbReserved2 = 0,
.lpReserved2 = null,
};
var piProcInfo: windows.PROCESS_INFORMATION = undefined;
const cwd_w = if (self.cwd) |cwd| try unicode.utf8ToUtf16LeWithNull(self.allocator, cwd) else null;
defer if (cwd_w) |cwd| self.allocator.free(cwd);
const cwd_w_ptr = if (cwd_w) |cwd| cwd.ptr else null;
const maybe_envp_buf = if (self.env_map) |env_map| try createWindowsEnvBlock(self.allocator, env_map) else null;
defer if (maybe_envp_buf) |envp_buf| self.allocator.free(envp_buf);
const envp_ptr = if (maybe_envp_buf) |envp_buf| envp_buf.ptr else null;
// the cwd set in ChildProcess is in effect when choosing the executable path
// to match posix semantics
const app_path = x: {
if (self.cwd) |cwd| {
const resolved = try fs.path.resolve(self.allocator, &[_][]const u8{ cwd, self.argv[0] });
defer self.allocator.free(resolved);
break :x try cstr.addNullByte(self.allocator, resolved);
} else {
break :x try cstr.addNullByte(self.allocator, self.argv[0]);
}
};
defer self.allocator.free(app_path);
const app_path_w = try unicode.utf8ToUtf16LeWithNull(self.allocator, app_path);
defer self.allocator.free(app_path_w);
const cmd_line_w = try unicode.utf8ToUtf16LeWithNull(self.allocator, cmd_line);
defer self.allocator.free(cmd_line_w);
windowsCreateProcess(app_path_w.ptr, cmd_line_w.ptr, envp_ptr, cwd_w_ptr, &siStartInfo, &piProcInfo) catch |no_path_err| {
if (no_path_err != error.FileNotFound) return no_path_err;
var free_path = true;
const PATH = process.getEnvVarOwned(self.allocator, "PATH") catch |err| switch (err) {
error.EnvironmentVariableNotFound => blk: {
free_path = false;
break :blk "";
},
else => |e| return e,
};
defer if (free_path) self.allocator.free(PATH);
var free_path_ext = true;
const PATHEXT = process.getEnvVarOwned(self.allocator, "PATHEXT") catch |err| switch (err) {
error.EnvironmentVariableNotFound => blk: {
free_path_ext = false;
break :blk "";
},
else => |e| return e,
};
defer if (free_path_ext) self.allocator.free(PATHEXT);
const app_name = self.argv[0];
var it = mem.tokenize(PATH, ";");
retry: while (it.next()) |search_path| {
const path_no_ext = try fs.path.join(self.allocator, &[_][]const u8{ search_path, app_name });
defer self.allocator.free(path_no_ext);
var ext_it = mem.tokenize(PATHEXT, ";");
while (ext_it.next()) |app_ext| {
const joined_path = try mem.concat(self.allocator, u8, &[_][]const u8{ path_no_ext, app_ext });
defer self.allocator.free(joined_path);
const joined_path_w = try unicode.utf8ToUtf16LeWithNull(self.allocator, joined_path);
defer self.allocator.free(joined_path_w);
if (windowsCreateProcess(joined_path_w.ptr, cmd_line_w.ptr, envp_ptr, cwd_w_ptr, &siStartInfo, &piProcInfo)) |_| {
break :retry;
} else |err| switch (err) {
error.FileNotFound => continue,
error.AccessDenied => continue,
else => return err,
}
}
} else {
return no_path_err; // return the original error
}
};
if (g_hChildStd_IN_Wr) |h| {
self.stdin = File{ .handle = h };
} else {
self.stdin = null;
}
if (g_hChildStd_OUT_Rd) |h| {
self.stdout = File{ .handle = h };
} else {
self.stdout = null;
}
if (g_hChildStd_ERR_Rd) |h| {
self.stderr = File{ .handle = h };
} else {
self.stderr = null;
}
self.handle = piProcInfo.hProcess;
self.thread_handle = piProcInfo.hThread;
self.term = null;
if (self.stdin_behavior == StdIo.Pipe) {
os.close(g_hChildStd_IN_Rd.?);
}
if (self.stderr_behavior == StdIo.Pipe) {
os.close(g_hChildStd_ERR_Wr.?);
}
if (self.stdout_behavior == StdIo.Pipe) {
os.close(g_hChildStd_OUT_Wr.?);
}
}
fn setUpChildIo(stdio: StdIo, pipe_fd: i32, std_fileno: i32, dev_null_fd: i32) !void {
switch (stdio) {
.Pipe => try os.dup2(pipe_fd, std_fileno),
.Close => os.close(std_fileno),
.Inherit => {},
.Ignore => try os.dup2(dev_null_fd, std_fileno),
}
}
};
fn windowsCreateProcess(app_name: [*:0]u16, cmd_line: [*:0]u16, envp_ptr: ?[*]u16, cwd_ptr: ?[*:0]u16, lpStartupInfo: *windows.STARTUPINFOW, lpProcessInformation: *windows.PROCESS_INFORMATION) !void {
// TODO the docs for environment pointer say:
// > A pointer to the environment block for the new process. If this parameter
// > is NULL, the new process uses the environment of the calling process.
// > ...
// > An environment block can contain either Unicode or ANSI characters. If
// > the environment block pointed to by lpEnvironment contains Unicode
// > characters, be sure that dwCreationFlags includes CREATE_UNICODE_ENVIRONMENT.
// > If this parameter is NULL and the environment block of the parent process
// > contains Unicode characters, you must also ensure that dwCreationFlags
// > includes CREATE_UNICODE_ENVIRONMENT.
// This seems to imply that we have to somehow know whether our process parent passed
// CREATE_UNICODE_ENVIRONMENT if we want to pass NULL for the environment parameter.
// Since we do not know this information that would imply that we must not pass NULL
// for the parameter.
// However this would imply that programs compiled with -DUNICODE could not pass
// environment variables to programs that were not, which seems unlikely.
// More investigation is needed.
return windows.CreateProcessW(
app_name,
cmd_line,
null,
null,
windows.TRUE,
windows.CREATE_UNICODE_ENVIRONMENT,
@ptrCast(?*c_void, envp_ptr),
cwd_ptr,
lpStartupInfo,
lpProcessInformation,
);
}
/// Caller must dealloc.
fn windowsCreateCommandLine(allocator: *mem.Allocator, argv: []const []const u8) ![:0]u8 {
var buf = try ArrayListSentineled(u8, 0).initSize(allocator, 0);
defer buf.deinit();
const buf_stream = buf.outStream();
for (argv) |arg, arg_i| {
if (arg_i != 0) try buf_stream.writeByte(' ');
if (mem.indexOfAny(u8, arg, " \t\n\"") == null) {
try buf_stream.writeAll(arg);
continue;
}
try buf_stream.writeByte('"');
var backslash_count: usize = 0;
for (arg) |byte| {
switch (byte) {
'\\' => backslash_count += 1,
'"' => {
try buf_stream.writeByteNTimes('\\', backslash_count * 2 + 1);
try buf_stream.writeByte('"');
backslash_count = 0;
},
else => {
try buf_stream.writeByteNTimes('\\', backslash_count);
try buf_stream.writeByte(byte);
backslash_count = 0;
},
}
}
try buf_stream.writeByteNTimes('\\', backslash_count * 2);
try buf_stream.writeByte('"');
}
return buf.toOwnedSlice();
}
fn windowsDestroyPipe(rd: ?windows.HANDLE, wr: ?windows.HANDLE) void {
if (rd) |h| os.close(h);
if (wr) |h| os.close(h);
}
fn windowsMakePipeIn(rd: *?windows.HANDLE, wr: *?windows.HANDLE, sattr: *const windows.SECURITY_ATTRIBUTES) !void {
var rd_h: windows.HANDLE = undefined;
var wr_h: windows.HANDLE = undefined;
try windows.CreatePipe(&rd_h, &wr_h, sattr);
errdefer windowsDestroyPipe(rd_h, wr_h);
try windows.SetHandleInformation(wr_h, windows.HANDLE_FLAG_INHERIT, 0);
rd.* = rd_h;
wr.* = wr_h;
}
fn windowsMakePipeOut(rd: *?windows.HANDLE, wr: *?windows.HANDLE, sattr: *const windows.SECURITY_ATTRIBUTES) !void {
var rd_h: windows.HANDLE = undefined;
var wr_h: windows.HANDLE = undefined;
try windows.CreatePipe(&rd_h, &wr_h, sattr);
errdefer windowsDestroyPipe(rd_h, wr_h);
try windows.SetHandleInformation(rd_h, windows.HANDLE_FLAG_INHERIT, 0);
rd.* = rd_h;
wr.* = wr_h;
}
fn destroyPipe(pipe: [2]os.fd_t) void {
os.close(pipe[0]);
if (pipe[0] != pipe[1]) os.close(pipe[1]);
}
// Child of fork calls this to report an error to the fork parent.
// Then the child exits.
fn forkChildErrReport(fd: i32, err: ChildProcess.SpawnError) noreturn {
writeIntFd(fd, @as(ErrInt, @errorToInt(err))) catch {};
os.exit(1);
}
const ErrInt = std.meta.Int(false, @sizeOf(anyerror) * 8);
fn writeIntFd(fd: i32, value: ErrInt) !void {
const file = File{
.handle = fd,
.capable_io_mode = .blocking,
.intended_io_mode = .blocking,
};
file.outStream().writeIntNative(u64, @intCast(u64, value)) catch return error.SystemResources;
}
fn readIntFd(fd: i32) !ErrInt {
const file = File{
.handle = fd,
.capable_io_mode = .blocking,
.intended_io_mode = .blocking,
};
return @intCast(ErrInt, file.inStream().readIntNative(u64) catch return error.SystemResources);
}
/// Caller must free result.
pub fn createWindowsEnvBlock(allocator: *mem.Allocator, env_map: *const BufMap) ![]u16 {
// count bytes needed
const max_chars_needed = x: {
var max_chars_needed: usize = 4; // 4 for the final 4 null bytes
var it = env_map.iterator();
while (it.next()) |pair| {
// +1 for '='
// +1 for null byte
max_chars_needed += pair.key.len + pair.value.len + 2;
}
break :x max_chars_needed;
};
const result = try allocator.alloc(u16, max_chars_needed);
errdefer allocator.free(result);
var it = env_map.iterator();
var i: usize = 0;
while (it.next()) |pair| {
i += try unicode.utf8ToUtf16Le(result[i..], pair.key);
result[i] = '=';
i += 1;
i += try unicode.utf8ToUtf16Le(result[i..], pair.value);
result[i] = 0;
i += 1;
}
result[i] = 0;
i += 1;
result[i] = 0;
i += 1;
result[i] = 0;
i += 1;
result[i] = 0;
i += 1;
return allocator.shrink(result, i);
}