use "alloc"use "env"use "errno"use "option"use "strfind"use "syswrap"use "slcp" pkg std = 	const execvp	: (cmd : byte[:], args : byte[:][:] -> errno)	const execvpe	: (cmd : byte[:], args : byte[:][:], env : byte[:][:] -> errno);; const execvp = {cmd, args	var i, j, paths, binpath	var buf : byte[512] 	match strfind(cmd, "/")	| `Some _:		-> execv(cmd, args)	| `None:		i = 0		j = 0		paths = std.getenvv("PATH", "/usr/local/bin:/bin:/usr/bin")		while j < paths.len			(i, j) = nextpath(paths, j)			binpath = mkpath(buf[:], paths[i:j], cmd)			execv(binpath, args)		;;	;;	-> -1} const execvpe = {cmd, args, env	var i, j, paths, binpath	var buf : byte[512] 	match strfind(cmd, "/")	| `Some _:		-> execve(cmd, args, env)	| `None:		i = 0		j = 0		paths = std.getenvv("PATH", "/usr/local/bin:/bin:/usr/bin")		while j < paths.len			(i, j) = nextpath(paths, j)			binpath = mkpath(buf[:], paths[i:j], cmd)			execve(binpath, args, env)		;;	;;	-> -1} const nextpath = {p, start	var i, j 	i = start	while i < p.len && p[i] == (':' : byte)		i++	;;	j = i	while j < p.len && p[j] != (':' : byte)		j++	;;	-> (i, j)} const mkpath = {buf, path, bin	var p, b 	p = path.len	b = bin.len	if buf.len < p + b + 1		-> ""	;;	std.slcp(buf[:p], path)	std.slcp(buf[p:p + 1], "/")	std.slcp(buf[p + 1:p + b + 1], bin)	-> buf[:p + b + 1]}