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452 lines
11 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <spawn.h>
#include <sys/wait.h>
/* Generally useful function -- what luaL_checkudata() should do */
static void *luaL_checkuserdata(lua_State *L, int idx, const char *tname)
{
void *ud;
luaL_argcheck(L, ud = luaL_checkudata(L, idx, tname), idx, tname);
return ud;
}
/* -- nil error */
static int push_error(lua_State *L)
{
lua_pushnil(L);
lua_pushstring(L, strerror(errno));
return 2;
}
/* name -- value/nil */
static int ex_getenv(lua_State *L)
{
const char *nam = luaL_checkstring(L, 1);
char *val = getenv(nam);
if (val)
lua_pushstring(L, val);
else
lua_pushnil(L);
return 1;
}
/* name value -- true/nil error */
static int ex_setenv(lua_State *L)
{
const char *nam = luaL_checkstring(L, 1);
const char *val = luaL_checkstring(L, 2);
if (-1 == setenv(nam, val, 1))
return push_error(L);
lua_pushboolean(L, 1);
return 1;
}
/* name -- true/nil error */
static int ex_unsetenv(lua_State *L)
{
const char *nam = luaL_checkstring(L, 1);
if (-1 == unsetenv(nam))
return push_error(L);
lua_pushboolean(L, 1);
return 1;
}
/* -- environment-table */
static int ex_environ(lua_State *L)
{
const char *nam, *val, *end;
const char **env;
lua_newtable(L);
for (env = (const char **)environ; (nam = *env); env++) {
end = strchr(val = strchr(nam, '=') + 1, '\0');
lua_pushlstring(L, nam, val - nam - 1);
lua_pushlstring(L, val, end - val);
lua_settable(L, -3);
}
return 1;
}
/* seconds -- */
static int ex_sleep(lua_State *L)
{
lua_Number seconds = luaL_checknumber(L, 1);
usleep(1e6 * seconds);
return 0;
}
/* pathname -- true/nil error */
static int ex_chdir(lua_State *L)
{
const char *pathname = luaL_checkstring(L, 1);
if (-1 == chdir(pathname))
return push_error(L);
lua_pushboolean(L, 1);
return 1;
}
/* pathname -- true/nil error */
static int ex_mkdir(lua_State *L)
{
const char *pathname = luaL_checkstring(L, 1);
if (-1 == mkdir(pathname, 0777))
return push_error(L);
lua_pushboolean(L, 1);
return 1;
}
/* -- pathname/nil error */
static int ex_currentdir(lua_State *L)
{
char pathname[PATH_MAX + 1];
if (!getcwd(pathname, sizeof pathname))
return push_error(L);
lua_pushstring(L, pathname);
return 1;
}
/* pathname -- iter state nil */
static int ex_dir(lua_State *L) { return luaL_error(L, "not yet implemented"); }
/* pathname/file -- entry */
static int ex_dirent(lua_State *L) { return luaL_error(L, "not yet implemented"); }
static int file_lock(lua_State *L, FILE *f, const char *mode, long offset, long length)
{
struct flock k;
switch (*mode) {
case 'w': k.l_type = F_WRLCK; break;
case 'r': k.l_type = F_RDLCK; break;
case 'u': k.l_type = F_UNLCK; break;
default: return luaL_error(L, "invalid mode");
}
k.l_whence = SEEK_SET;
k.l_start = offset;
k.l_len = length;
if (-1 == fcntl(fileno(f), F_SETLK, &k))
return push_error(L);
lua_pushboolean(L, 1);
return 1;
}
/* file mode [offset [length]] -- true/nil error */
static int ex_lock(lua_State *L)
{
FILE **pf = luaL_checkuserdata(L, 1, LUA_FILEHANDLE);
const char *mode = luaL_checkstring(L, 2);
long offset = luaL_optnumber(L, 3, 0);
long length = luaL_optnumber(L, 4, 0);
return file_lock(L, *pf, mode, offset, length);
}
/* file [offset [length]] -- true/nil error */
static int ex_unlock(lua_State *L)
{
lua_pushliteral(L, "u");
lua_insert(L, 2);
return ex_lock(L);
}
/* -- LUA_FILEHANDLE file file */
static int make_pipe(lua_State *L, FILE *i, FILE *o)
{
FILE **pf;
luaL_getmetatable(L, LUA_FILEHANDLE);
*(pf = lua_newuserdata(L, sizeof *pf)) = i;
lua_pushvalue(L, -2);
lua_setmetatable(L, -2);
*(pf = lua_newuserdata(L, sizeof *pf)) = o;
lua_pushvalue(L, -2);
lua_setmetatable(L, -2);
return 2;
}
/* -- in out/nil error */
static int ex_pipe(lua_State *L)
{
int fd[2];
if (-1 == pipe(fd))
return push_error(L);
return make_pipe(L, fdopen(fd[0], "r"), fdopen(fd[1], "w"));
}
/* ... argtab -- ... */
static const char **build_vector(lua_State *L)
{
size_t i, n = lua_objlen(L, -1);
const char **vec = lua_newuserdata(L, (n + 2) * sizeof *vec);
/* ... arr vec */
for (i = 0; i <= n; i++) {
lua_rawgeti(L, -2, i); /* ... arr vec elem */
vec[i] = lua_tostring(L, -1);
lua_pop(L, 1); /* ... arr vec */
}
vec[n + 1] = 0;
lua_replace(L, -2); /* ... vector */
return vec;
}
struct spawn_params {
lua_State *L;
const char *command, **argv, **envp;
posix_spawn_file_actions_t file_actions;
int has_actions;
};
/* filename ... */
static void spawn_param_filename(struct spawn_params *p)
{
/* XXX confusing */
p->command = luaL_checkstring(p->L, 1);
}
static void spawn_param_defaults(struct spawn_params *p)
{
p->argv = lua_newuserdata(p->L, 2 * sizeof *p->argv);
p->argv[0] = p->command;
p->argv[1] = 0;
p->envp = (const char **)environ;
p->has_actions = 0;
}
/* ... argtab */
static void spawn_param_args(struct spawn_params *p)
{
const char **argv = build_vector(p->L);
if (!argv[0]) argv[0] = p->command;
p->argv = argv;
}
/* ... envtab/nil */
static void spawn_param_env(struct spawn_params *p)
{
size_t i = 0;
luaL_Buffer estr;
if (lua_isnil(p->L, -1)) {
p->envp = (const char **)environ;
return;
}
luaL_buffinit(p->L, &estr);
lua_newtable(p->L); /* ... envtab arr */
lua_pushnil(p->L); /* ... envtab arr nil */
for (i = 0; lua_next(p->L, -3); i++) { /* ... envtab arr k v */
luaL_prepbuffer(&estr);
lua_pushvalue(p->L, -2); /* ... envtab arr k v k */
luaL_addvalue(&estr);
luaL_putchar(&estr, '=');
lua_pop(p->L, 1); /* ... envtab arr k v */
luaL_addvalue(&estr);
lua_pop(p->L, 1); /* ... envtab arr k */
luaL_pushresult(&estr); /* ... envtab arr k estr */
lua_rawseti(p->L, -3, i); /* ... envtab arr[n]=estr k */
} /* ... envtab arr */
lua_replace(p->L, -2); /* ... arr */
build_vector(p->L); /* ... arr */
}
/* _ opts ... */
static int get_redirect(lua_State *L, posix_spawn_file_actions_t *file_actions,
const char *stdname, int descriptor)
{
int ret;
lua_getfield(L, 2, stdname);
if ((ret = !lua_isnil(L, -1)))
posix_spawn_file_actions_adddup2(file_actions,
fileno(luaL_checkudata(L, -1, LUA_FILEHANDLE)), descriptor);
lua_pop(L, 1);
return ret;
}
/* _ opts ... */
static void spawn_param_redirects(struct spawn_params *p)
{
posix_spawn_file_actions_init(&p->file_actions);
p->has_actions = 1;
get_redirect(p->L, &p->file_actions, "stdin", STDIN_FILENO);
get_redirect(p->L, &p->file_actions, "stdout", STDOUT_FILENO);
get_redirect(p->L, &p->file_actions, "stderr", STDERR_FILENO);
}
#define PROCESS_HANDLE "process"
struct process {
int status;
pid_t pid;
};
static int spawn_param_execute(struct spawn_params *p, struct process *proc)
{
int ret;
proc->status = -1;
ret = posix_spawnp(&proc->pid, p->command, &p->file_actions, 0, (char *const *)p->argv, (char *const *)p->envp);
if (p->has_actions)
posix_spawn_file_actions_destroy(&p->file_actions);
return ret == 0;
}
/* filename [args-opts] -- true/nil,error */
/* args-opts -- true/nil,error */
static int ex_spawn(lua_State *L)
{
struct spawn_params params = {L};
struct process *proc;
if (lua_type(L, 1) == LUA_TTABLE) {
lua_getfield(L, 1, "command"); /* opts ... cmd */
if (!lua_isnil(L, -1)) {
/* convert {command=command,arg1,...} to command {arg1,...} */
lua_insert(L, 1); /* cmd opts ... */
}
else {
/* convert {arg0,arg1,...} to arg0 {arg1,...} */
size_t i, n = lua_objlen(L, 1);
lua_rawgeti(L, 1, 1); /* opts ... nil cmd */
if (lua_isnil(L, -1))
luaL_error(L, "no command specified");
/* XXX check LUA_TSTRING */
lua_insert(L, 1); /* cmd opts ... nil */
for (i = 2; i <= n; i++) {
lua_rawgeti(L, 2, i); /* cmd opts ... nil argi */
lua_rawseti(L, 2, i - 1); /* cmd opts ... nil */
}
lua_rawseti(L, 2, n); /* cmd opts ... */
}
}
/* get filename to execute */
spawn_param_filename(&params);
/* get arguments, environment, and redirections */
switch (lua_type(L, 2)) {
default: luaL_argerror(L, 2, "expected options table"); break;
case LUA_TNONE:
spawn_param_defaults(&params);
break;
case LUA_TTABLE:
lua_getfield(L, 2, "args"); /* cmd opts ... argtab */
switch (lua_type(L, -1)) {
default: luaL_error(L, "args option must be an array"); break;
case LUA_TNIL:
lua_pop(L, 1); /* cmd opts ... */
lua_pushvalue(L, 2); /* cmd opts ... opts */
if (0) /*FALLTHRU*/
case LUA_TTABLE:
if (lua_objlen(L, 2) > 0)
luaL_error(L, "cannot specify both the args option and array values");
spawn_param_args(&params); /* cmd opts ... */
break;
}
lua_getfield(L, 2, "env"); /* cmd opts ... envtab */
switch (lua_type(L, -1)) {
default: luaL_error(L, "env option must be a table"); break;
case LUA_TNIL:
case LUA_TTABLE:
spawn_param_env(&params); /* cmd opts ... */
break;
}
spawn_param_redirects(&params);
}
proc = lua_newuserdata(L, sizeof *proc); /* cmd opts ... proc */
luaL_getmetatable(L, PROCESS_HANDLE); /* cmd opts ... proc M */
lua_setmetatable(L, -2); /* cmd opts ... proc */
if (!spawn_param_execute(&params, proc))
return push_error(L);
return 1; /* ... proc */
}
/* proc -- exitcode/nil error */
static int process_wait(lua_State *L)
{
struct process *p = luaL_checkudata(L, 1, PROCESS_HANDLE);
if (p->status == -1) {
int status;
if (-1 == waitpid(p->pid, &status, 0))
return push_error(L);
p->status = WEXITSTATUS(status);
}
lua_pushnumber(L, p->status);
return 1;
}
static const luaL_reg ex_iolib[] = {
{"pipe", ex_pipe},
{0,0}
};
static const luaL_reg ex_iofile_methods[] = {
{"lock", ex_lock},
{"unlock", ex_unlock},
{0,0}
};
static const luaL_reg ex_oslib[] = {
{"getenv", ex_getenv},
{"setenv", ex_setenv},
{"unsetenv", ex_unsetenv},
{"environ", ex_environ},
{"sleep", ex_sleep},
{"chdir", ex_chdir},
{"mkdir", ex_mkdir},
{"currentdir", ex_currentdir},
{"dir", ex_dir},
{"dirent", ex_dirent},
{"spawn", ex_spawn},
{0,0}
};
static const luaL_reg ex_process_methods[] = {
{"wait", process_wait},
{0,0}
};
int luaopen_ex(lua_State *L)
{
/* extend the io table */
lua_getglobal(L, "io");
if (lua_isnil(L, -1)) luaL_error(L, "io not loaded");
luaL_openlib(L, 0, ex_iolib, 0);
/* extend the os table */
lua_getglobal(L, "os");
if (lua_isnil(L, -1)) luaL_error(L, "os not loaded");
luaL_openlib(L, "os", ex_oslib, 0);
/* extend the io.file metatable */
luaL_getmetatable(L, LUA_FILEHANDLE);
if (lua_isnil(L, -1)) luaL_error(L, "can't find FILE* metatable");
luaL_openlib(L, 0, ex_iofile_methods, 0);
/* proc metatable */
luaL_newmetatable(L, PROCESS_HANDLE); /* proc */
luaL_openlib(L, 0, ex_process_methods, 0); /* proc */
lua_pushliteral(L, "__index"); /* proc __index */
lua_pushvalue(L, -2); /* proc __index proc */
lua_settable(L, -3); /* proc */
/* for lack of a better thing to return */
lua_pushboolean(L, 1);
return 1;
}