1 /*
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 2023 Baptiste Daroussin <bapt@FreeBSD.org>
5 * Copyright (C) 2025 Kyle Evans <kevans@FreeBSD.org>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted providing that the following conditions~
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
25 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/wait.h>
30
31 #include <errno.h>
32 #include <fcntl.h>
33 #include <spawn.h>
34 #include <stdbool.h>
35 #include <string.h>
36 #include <stdio.h>
37 #include <unistd.h>
38
39 #include <lua.h>
40 #include "lauxlib.h"
41 #include "lfbsd.h"
42
43 #define FBSD_PROCESSHANDLE "fbsd_process_t*"
44
45 struct fbsd_process {
46 int pid;
47 int stdin_fileno;
48 int stdout_fileno;
49 };
50
51 extern char **environ;
52
53 static const char**
luaL_checkarraystrings(lua_State * L,int arg)54 luaL_checkarraystrings(lua_State *L, int arg)
55 {
56 const char **ret;
57 lua_Integer n, i;
58 int t;
59 int abs_arg = lua_absindex(L, arg);
60 luaL_checktype(L, abs_arg, LUA_TTABLE);
61 n = lua_rawlen(L, abs_arg);
62 ret = lua_newuserdata(L, (n+1)*sizeof(char*));
63 for (i=0; i<n; i++) {
64 t = lua_rawgeti(L, abs_arg, i+1);
65 if (t == LUA_TNIL)
66 break;
67 luaL_argcheck(L, t == LUA_TSTRING, arg, "expected array of strings");
68 ret[i] = lua_tostring(L, -1);
69 lua_pop(L, 1);
70 }
71 ret[i] = NULL;
72 return ret;
73 }
74
75 static void
close_pipes(int pipes[2])76 close_pipes(int pipes[2])
77 {
78
79 if (pipes[0] != -1)
80 close(pipes[0]);
81 if (pipes[1] != -1)
82 close(pipes[1]);
83 }
84
85 static int
lua_exec(lua_State * L)86 lua_exec(lua_State *L)
87 {
88 struct fbsd_process *proc;
89 int r;
90 posix_spawn_file_actions_t action;
91 int stdin_pipe[2] = {-1, -1};
92 int stdout_pipe[2] = {-1, -1};
93 pid_t pid;
94 const char **argv;
95 int n = lua_gettop(L);
96 bool capture_stdout;
97 luaL_argcheck(L, n > 0 && n <= 2, n >= 2 ? 2 : n,
98 "fbsd.exec takes exactly one or two arguments");
99
100 capture_stdout = lua_toboolean(L, 2);
101 if (pipe(stdin_pipe) < 0) {
102 lua_pushnil(L);
103 lua_pushstring(L, strerror(errno));
104 lua_pushinteger(L, errno);
105 return (3);
106 }
107 if (capture_stdout && pipe(stdout_pipe) < 0) {
108 close_pipes(stdin_pipe);
109 lua_pushnil(L);
110 lua_pushstring(L, strerror(errno));
111 lua_pushinteger(L, errno);
112 return (3);
113 }
114
115 proc = lua_newuserdata(L, sizeof(*proc));
116 proc->stdin_fileno = stdin_pipe[1];
117 proc->stdout_fileno = stdout_pipe[1];
118 posix_spawn_file_actions_init(&action);
119 posix_spawn_file_actions_adddup2(&action, stdin_pipe[0], STDIN_FILENO);
120 posix_spawn_file_actions_addclose(&action, stdin_pipe[1]);
121 if (stdin_pipe[0] != STDIN_FILENO)
122 posix_spawn_file_actions_addclose(&action, stdin_pipe[0]);
123
124 /*
125 * Setup stdout to be captured if requested. Otherwise, we just let it
126 * go to our own stdout.
127 */
128 if (stdout_pipe[0] != -1) {
129 posix_spawn_file_actions_adddup2(&action, stdout_pipe[0],
130 STDOUT_FILENO);
131 posix_spawn_file_actions_addclose(&action, stdout_pipe[1]);
132 if (stdout_pipe[0] != STDOUT_FILENO) {
133 posix_spawn_file_actions_addclose(&action,
134 stdout_pipe[0]);
135 }
136 }
137
138 argv = luaL_checkarraystrings(L, 1);
139 if (0 != (r = posix_spawnp(&pid, argv[0], &action, NULL,
140 (char*const*)argv, environ))) {
141 close_pipes(stdin_pipe);
142 close_pipes(stdout_pipe);
143 posix_spawn_file_actions_destroy(&action);
144 lua_pop(L, 2); /* Pop off the process handle and args. */
145
146 lua_pushnil(L);
147 lua_pushstring(L, strerror(r));
148 lua_pushinteger(L, r);
149 return (3);
150 }
151
152 lua_pop(L, 1);
153
154 close(stdin_pipe[0]);
155 if (stdout_pipe[0] != -1)
156 close(stdout_pipe[0]);
157 posix_spawn_file_actions_destroy(&action);
158
159 proc->pid = pid;
160 luaL_setmetatable(L, FBSD_PROCESSHANDLE);
161
162 return (1);
163 }
164
165 static int
lua_process_close(lua_State * L)166 lua_process_close(lua_State *L)
167 {
168 struct fbsd_process *proc;
169 int pstat, r;
170
171 proc = luaL_checkudata(L, 1, FBSD_PROCESSHANDLE);
172 while (waitpid(proc->pid, &pstat, 0) == -1) {
173 if ((r = errno) != EINTR) {
174 lua_pushnil(L);
175 lua_pushstring(L, strerror(r));
176 lua_pushinteger(L, r);
177 return (3);
178 }
179 }
180
181 if (!WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0) {
182 lua_pushnil(L);
183 lua_pushstring(L, "Abnormal termination");
184 return (2);
185 }
186
187 if (proc->stdin_fileno >= 0) {
188 close(proc->stdin_fileno);
189 proc->stdin_fileno = -1;
190 }
191
192 if (proc->stdout_fileno >= 0) {
193 close(proc->stdout_fileno);
194 proc->stdout_fileno = -1;
195 }
196
197 lua_pushboolean(L, 1);
198 return (1);
199 }
200
201 static int
lua_process_makestdio(lua_State * L,int fd,const char * mode)202 lua_process_makestdio(lua_State *L, int fd, const char *mode)
203 {
204 luaL_Stream *p;
205 FILE *fp;
206 int r;
207
208 if (fd == -1) {
209 lua_pushnil(L);
210 lua_pushstring(L, "Stream not captured");
211 return (2);
212 }
213
214 fp = fdopen(fd, mode);
215 if (fp == NULL) {
216 r = errno;
217
218 lua_pushnil(L);
219 lua_pushstring(L, strerror(r));
220 lua_pushinteger(L, r);
221 return (3);
222 }
223
224 p = lua_newuserdata(L, sizeof(*p));
225 p->closef = &lua_process_close;
226 p->f = fp;
227 luaL_setmetatable(L, LUA_FILEHANDLE);
228 return (1);
229 }
230
231 static int
lua_process_stdin(lua_State * L)232 lua_process_stdin(lua_State *L)
233 {
234 struct fbsd_process *proc;
235
236 proc = luaL_checkudata(L, 1, FBSD_PROCESSHANDLE);
237 return (lua_process_makestdio(L, proc->stdin_fileno, "w"));
238 }
239
240 static int
lua_process_stdout(lua_State * L)241 lua_process_stdout(lua_State *L)
242 {
243 struct fbsd_process *proc;
244
245 proc = luaL_checkudata(L, 1, FBSD_PROCESSHANDLE);
246 return (lua_process_makestdio(L, proc->stdout_fileno, "r"));
247 }
248
249 #define PROCESS_SIMPLE(n) { #n, lua_process_ ## n }
250 static const struct luaL_Reg fbsd_process[] = {
251 PROCESS_SIMPLE(close),
252 PROCESS_SIMPLE(stdin),
253 PROCESS_SIMPLE(stdout),
254 { NULL, NULL },
255 };
256
257 static const struct luaL_Reg fbsd_process_meta[] = {
258 { "__index", NULL },
259 { "__gc", lua_process_close },
260 { "__close", lua_process_close },
261 { NULL, NULL },
262 };
263
264 #define REG_SIMPLE(n) { #n, lua_ ## n }
265 static const struct luaL_Reg fbsd_lib[] = {
266 REG_SIMPLE(exec),
267 { NULL, NULL },
268 };
269 #undef REG_SIMPLE
270
271 int
luaopen_fbsd(lua_State * L)272 luaopen_fbsd(lua_State *L)
273 {
274 luaL_newlib(L, fbsd_lib);
275
276 luaL_newmetatable(L, FBSD_PROCESSHANDLE);
277 luaL_setfuncs(L, fbsd_process_meta, 0);
278
279 luaL_newlibtable(L, fbsd_process);
280 luaL_setfuncs(L, fbsd_process, 0);
281 lua_setfield(L, -2, "__index");
282 lua_pop(L, 1);
283
284 return (1);
285 }
286