libs/nixio/src/process.c

   1 /*
   2  * nixio - Linux I/O library for lua
   3  *
   4  *   Copyright (C) 2009 Steven Barth <steven@midlink.org>
   5  *
   6  *  Licensed under the Apache License, Version 2.0 (the "License");
   7  *  you may not use this file except in compliance with the License.
   8  *  You may obtain a copy of the License at
   9  *
  10  *      http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  *  Unless required by applicable law or agreed to in writing, software
  13  *  distributed under the License is distributed on an "AS IS" BASIS,
  14  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  *  See the License for the specific language governing permissions and
  16  *  limitations under the License.
  17  */
  18
  19 #include "nixio.h"
  20 #include <unistd.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <sys/wait.h>
  24
  25 static int nixio_fork(lua_State *L) {
  26         pid_t pid = fork();
  27         if (pid == -1) {
  28                 return nixio__perror(L);
  29         } else {
  30                 lua_pushinteger(L, pid);
  31                 return 1;
  32         }
  33 }
  34
  35 static int nixio_wait(lua_State *L) {
  36         pid_t pidin = luaL_optinteger(L, 1, -1), pidout;
  37         int options = 0, status;
  38
  39         const int j = lua_gettop(L);
  40         for (int i=2; i<=j; i++) {
  41                 const char *flag = luaL_checkstring(L, i);
  42                 if (!strcmp(flag, "nohang")) {
  43                         options |= WNOHANG;
  44                 } else if (!strcmp(flag, "untraced")) {
  45                         options |= WUNTRACED;
  46                 } else if (!strcmp(flag, "continued")) {
  47                         options |= WCONTINUED;
  48                 } else {
  49                         return luaL_argerror(L, i,
  50                                         "supported values: nohang, untraced, continued");
  51                 }
  52         }
  53
  54         do {
  55                 pidout = waitpid(pidin, &status, options);
  56         } while (pidout == -1 && errno == EINTR);
  57
  58         if (pidout == -1) {
  59                 return nixio__perror(L);
  60         } else {
  61                 lua_pushinteger(L, pidout);
  62         }
  63
  64         if (WIFEXITED(status)) {
  65                 lua_pushliteral(L, "exited");
  66                 lua_pushinteger(L, WEXITSTATUS(status));
  67     } else if (WIFSIGNALED(status)) {
  68         lua_pushliteral(L, "signaled");
  69         lua_pushinteger(L, WTERMSIG(status));
  70     } else if (WIFSTOPPED(status)) {
  71         lua_pushliteral(L, "stopped");
  72         lua_pushinteger(L, WSTOPSIG(status));
  73     } else {
  74         return 1;
  75     }
  76
  77     return 3;
  78 }
  79
  80 static int nixio_kill(lua_State *L) {
  81         return nixio__pstatus(L, !kill(luaL_checkint(L, 1), luaL_checkint(L, 2)));
  82 }
  83
  84
  85 /* module table */
  86 static const luaL_reg R[] = {
  87         {"fork",                nixio_fork},
  88         {"wait",                nixio_wait},
  89         {"kill",                nixio_kill},
  90         {NULL,                  NULL}
  91 };
  92
  93 void nixio_open_process(lua_State *L) {
  94         luaL_register(L, NULL, R);
  95 }