spawn.c

   1 /*
   2  * spawn.c - Lua configuration management
   3  *
   4  * Copyright © 2009 Julien Danjou <julien@danjou.info>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  */
  21
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26
  27 #include "structs.h"
  28 #include "spawn.h"
  29 #include "luaa.h"
  30
  31 /** Spawn a program.
  32  * This function is multi-head (Zaphod) aware and will set display to
  33  * the right screen according to mouse position.
  34  * \param L The Lua VM state.
  35  * \return The number of elements pushed on stack
  36  * \luastack
  37  * \lparam The command to launch.
  38  * \lparam The optional screen number to spawn the command on.
  39  */
  40 int
  41 luaA_spawn(lua_State *L)
  42 {
  43     char *host, newdisplay[128];
  44     const char *cmd;
  45     int screen = 0, screenp, displayp;
  46
  47     if(lua_gettop(L) == 2)
  48     {
  49         screen = luaL_checknumber(L, 2) - 1;
  50         luaA_checkscreen(screen);
  51     }
  52
  53     cmd = luaL_checkstring(L, 1);
  54
  55     if(!globalconf.xinerama_is_active)
  56     {
  57         xcb_parse_display(NULL, &host, &displayp, &screenp);
  58         snprintf(newdisplay, sizeof(newdisplay), "%s:%d.%d", host, displayp, screen);
  59         setenv("DISPLAY", newdisplay, 1);
  60         p_delete(&host);
  61     }
  62
  63     /* The double-fork construct avoids zombie processes and keeps the code
  64      * clean from stupid signal handlers. */
  65     if(fork() == 0)
  66     {
  67         if(fork() == 0)
  68         {
  69             if(globalconf.connection)
  70                 xcb_disconnect(globalconf.connection);
  71             setsid();
  72             a_exec(cmd);
  73             warn("execl '%s' failed: %s\n", cmd, strerror(errno));
  74         }
  75         exit(EXIT_SUCCESS);
  76     }
  77     wait(0);
  78
  79     return 0;
  80 }
  81
  82 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80