compiler/clib/waitpid.c

   1 /*
   2     Copyright © 2004-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #define DEBUG 0
   7
   8 #include <aros/debug.h>
   9 #include <proto/exec.h>
  10 #include <exec/lists.h>
  11 #include <aros/startup.h>
  12
  13 #include <sys/types.h>
  14 #include <errno.h>
  15
  16 #include "__arosc_privdata.h"
  17
  18 /*****************************************************************************
  19
  20     NAME */
  21 #include <sys/wait.h>
  22
  23         pid_t waitpid(
  24
  25 /*  SYNOPSIS */
  26         pid_t pid,
  27         int *status,
  28         int options)
  29
  30 /*  FUNCTION
  31         Waits for child process with given process id to change state. State
  32         change is one of the following events: child has exited, child was
  33         terminated by a signal, child was stopped by a signal, child was
  34         resumed by a signal.
  35
  36         The function stores status of the process that changed state in the
  37         pointer given as status argument.
  38
  39         The following macros can be used to extract information from the
  40         status value:
  41
  42         WIFEXITED(status)    - true if the process has exited
  43         WEXITSTATUS(status)  - exit status of the exited process
  44         WIFSIGNALED(status)  - true if the child process was terminated by a
  45                                signal
  46         WTERMSIG(status)     - number of the signal that caused process
  47                                termination
  48         WIFSTOPPED(status)   - true if the child process was stopped by a
  49                                signal
  50         WSTOPSIG(status)     - number of the signal that caused child process
  51                                stop
  52         WIFCONTINUED(status) - true if the child process was resumed by the
  53                                SIGCONT signal.
  54
  55         Unless WNOHANG option is set, parent process will be suspended until a
  56         child changes state. If a child process has already changed state,
  57         function returns immediately.
  58
  59     INPUTS
  60         pid - Process id of the process you want to wait for or -1 to wait for
  61                 any child process
  62         status - Pointer to int where child status will be stored or NULL if
  63                 you don't want to store status.
  64         options - ORed zero or more of the following constants:
  65
  66             WNOHANG - return immediately if no child process changed state
  67
  68     RESULT
  69         Process id of the child process on success or -1 on error. If an error
  70         occurred, the global variable errno is set.
  71
  72     NOTES
  73         This function will work only for child processeses notifying parent
  74         process of their death, for example processes created by vfork() call.
  75         If you want to use it for other processes, remember to set the
  76         NP_NotifyOnDeath tag value to TRUE during child process creation.
  77
  78     EXAMPLE
  79
  80     BUGS
  81
  82     SEE ALSO
  83         wait()
  84
  85     INTERNALS
  86         Since POSIX signals are not yet implemented, WIFSIGNALED, WIFSTOPPED
  87         and WIFCONTINUED macros always return 0. WIFEXITED always returns 1.
  88
  89         The et_UniqueID field of the ETask structure is used as process id.
  90
  91 ******************************************************************************/
  92 {
  93     struct ETask *et;
  94     ULONG tid = pid;
  95     pid_t ret = -1;
  96     int exchildno;
  97
  98     D(bug("waitpid(%d, %p, %d)\n", pid, status, options));
  99
 100     et = GetETask(FindTask(NULL));
 101     if(!et)
 102     {
 103         /* only ETasks are fertile */
 104         errno = ECHILD;
 105         return -1;
 106     }
 107
 108     if (pid < -1 || pid == 0)
 109     {
 110         /* process groups not yet supported */
 111         errno = EINVAL;
 112         return -1;
 113     }
 114
 115     if (pid == -1)
 116         tid = 0;
 117
 118     if(tid != 0 && ChildStatus(tid) == CHILD_NOTFOUND)
 119     {
 120         /* error if there's no such child */
 121         errno = ECHILD;
 122         return -1;
 123     }
 124
 125     if (options & ~WNOHANG)
 126     {
 127         /* option not yet supported */
 128         errno = EINVAL;
 129         return -1;
 130     }
 131
 132     /* not very pretty, perhaps we need a function for counting dead
 133        children? */
 134     ListLength(&et->et_TaskMsgPort.mp_MsgList, exchildno);
 135     if ((options & WNOHANG) && (
 136         (tid != 0 && ChildStatus(tid) != CHILD_EXITED) ||
 137         (tid == 0 && exchildno == 0)
 138     ))
 139     {
 140         D(bug("waitpid: no dead children\n"));
 141         /* no dead children atm */
 142         return 0;
 143     }
 144
 145     D(bug("waitpid: wait for %d to die\n", tid));
 146     et = (struct ETask *)ChildWait(tid);
 147     if (et != (struct ETask *)CHILD_NOTNEW)
 148     {
 149         if(status)
 150         {
 151             *status = et->et_Result1;
 152         }
 153         ret = et->et_UniqueID;
 154         ChildFree(et->et_UniqueID);
 155     }
 156     else
 157         errno = ECHILD;
 158
 159     D(bug("waitpid: leaving (%d)\n", ret));
 160
 161     return ret;
 162 }