compiler/clib/__spawnv.c

   1 /*
   2     Copyright © 1995-2009, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     spavnv() function, used to spawn new processes.
   6 */
   7 #define DEBUG 0
   8 #include "__arosc_privdata.h"
   9
  10 #include <proto/dos.h>
  11 #include <proto/exec.h>
  12 #include <dos/dos.h>
  13 #include <dos/dosextens.h>
  14 #include <dos/filesystem.h>
  15 #include <aros/debug.h>
  16
  17 #include <unistd.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <errno.h>
  21 #include <assert.h>
  22 #include <sys/syscall.h>
  23 #include <sys/wait.h>
  24
  25 /*****************************************************************************
  26
  27     NAME */
  28 #include <process.h>
  29
  30         int __spawnv(
  31
  32 /*  SYNOPSIS */
  33          int         mode,
  34          const char *filename,
  35          int         searchpath,
  36          char *const argv[])
  37
  38 /*  FUNCTION
  39         Spawn a child process, given a vector of arguments and an already LoadSeg()'d executable.
  40
  41     INPUTS
  42         mode - the way the child process has to be loaded, and how the parent has to behave
  43                after the child process is initiated. Specify one of the following values:
  44
  45                P_WAIT    - the child program is loaded into memory, then it's executed while
  46                            the parent process waits for it to terminate, at which point the
  47                            patent process resumes execution.
  48
  49                P_NOWAIT  - the parent program is executed concurrently with the new child process.
  50
  51                P_OVERLAY - teplace the parent program with the child program in memory and then
  52                            execute the child. The parent program will never be resumed. This
  53                            mode is equivalent to calling one of the exec*() functions.
  54
  55         filename  - command to execute
  56
  57         searchpath - boolean to indicate if path should be searched for command
  58
  59         argv - a pointer to a NULL terminated array of strings representing arguments to pass
  60                to the child process. The first entry in the array is conventionally the name of
  61                the program to spawn, but in any case it must _never_ be NULL, and the argv
  62                pointer itself must never be NULL either.
  63
  64     RESULT
  65
  66         If P_WAIT is specified, then the return code of the child program is returned.
  67         If instead P_NOWAIT is used, then the pid of the newly created process is returned.
  68         Finally, if P_OVERLAY is used, the function doesn't return unless an error has occurred,
  69         in which case -1 is returned also for the other modes and the global errno variable will
  70         hold the proper error code.
  71
  72     NOTES
  73
  74         The way the child process behaves regarding parent's file descriptors, signal handlers
  75         and so on is the same way it would behave with one of the exec*(3) functions.
  76         This, for one, means that all filedescriptors are inherited except the ones which have
  77         the close-on-exec flag set.
  78
  79     EXAMPLE
  80
  81     BUGS
  82
  83     SEE ALSO
  84         execl(), execle(), execlp(), execlpe(), execv(), execve(), execvp(), execvpe(), getenv(),
  85         putenv(), setenv(), spawn(), spawnl(), spawnle(), spawnlp(), spawnlpe(), spawnp(),
  86         spawnve(), spawnvp(), spawnvpe(), wait(), waitpid()
  87
  88     INTERNALS
  89
  90         For now only the stdin, stout and stderr file descriptors are inherited, and signals
  91         are not handled yet.
  92
  93 ******************************************************************************/
  94 {
  95     switch (mode)
  96     {
  97         case P_NOWAIT:
  98         case P_WAIT:
  99         {
 100             pid_t pid;
 101             int ret = 0;
 102
 103             pid = vfork();
 104
 105             D(bug("__spawnv: vfork pid = %d\n", pid));
 106
 107             if (pid > 0)
 108             {
 109                 if (ret != 0)
 110                 {
 111                     D(bug("__spawnv: From parent child returned %d from execv,\n"
 112                           "          errno = %d\n", ret, errno));
 113                     /* Child exec did return => error */
 114                     return -1;
 115                 }
 116
 117                 if (mode == P_WAIT)
 118                 {
 119                     int status;
 120
 121                     D(bug("__spawnv: waiting for child with waitpid\n", ret));
 122
 123                     waitpid(pid, &status, 0);
 124
 125                     D(bug("__spawnv: child exited\n", ret));
 126
 127                     if (WIFEXITED(status))
 128                         return WEXITSTATUS(status);
 129                     else
 130                         /* FIXME: Is this the right thing to do ? */
 131                         return -1;
 132                 }
 133                 else /* mode == P_NOWAIT */
 134                     return pid;
 135             }
 136             else if (pid == 0)
 137             {
 138                 if (searchpath)
 139                     ret = execvp(filename, argv);
 140                 else
 141                     ret = execv(filename, argv);
 142
 143                 D(bug("__spawnv: Child exec returned %d\n", ret));
 144
 145                 _exit(0);
 146             }
 147             else /* Error in vfork */
 148                 return -1;
 149         }
 150         break;
 151
 152         case P_OVERLAY:
 153         {
 154             if (searchpath)
 155                 return execvp(filename, argv);
 156             else
 157                 return execv(filename, argv);
 158
 159             assert(0);
 160         }
 161         break;
 162
 163         default:
 164         errno = EINVAL;
 165         return -1;
 166     }
 167
 168     assert(0); /* Should not be reached */
 169     errno = ENOSYS;
 170     return -1;
 171 }