compiler/clib/waitpid.c

   1 /*
   2     Copyright © 2004-2009, 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 <sys/wait.h>
  15 #include <errno.h>
  16
  17 #include "etask.h"
  18 #include "__arosc_privdata.h"
  19
  20 /*****************************************************************************
  21
  22     NAME */
  23
  24         pid_t waitpid(
  25
  26 /*  SYNOPSIS */
  27         pid_t pid,
  28         int *status,
  29         int options)
  30
  31 /*  FUNCTION
  32         Waits for child process with given process id to change state. State
  33         change is one of the following events: child has exited, child was
  34         terminated by a signal, child was stopped by a signal, child was
  35         resumed by a signal.
  36
  37         The function stores status of the process that changed state in the
  38         pointer given as status argument.
  39
  40         The following macros can be used to extract information from the
  41         status value:
  42
  43         WIFEXITED(status)    - true if the process has exited
  44         WEXITSTATUS(status)  - exit status of the exited process
  45         WIFSIGNALED(status)  - true if the child process was terminated by a
  46                                signal
  47         WTERMSIG(status)     - number of the signal that caused process
  48                                termination
  49         WIFSTOPPED(status)   - true if the child process was stopped by a
  50                                signal
  51         WSTOPSIG(status)     - number of the signal that caused child process
  52                                stop
  53         WIFCONTINUED(status) - true if the child process was resumed by the
  54                                SIGCONT signal.
  55
  56         Unless WNOHANG option is set, parent process will be suspended until a
  57         child changes state. If a child process has already changed state,
  58         function returns immediately.
  59
  60     INPUTS
  61         pid - Process id of the process you want to wait for or -1 to wait for
  62                 any child process
  63         status - Pointer to int where child status will be stored or NULL if
  64                 you don't want to store status.
  65         options - ORed zero or more of the following constants:
  66
  67             WNOHANG - return immediately if no child process changed state
  68
  69     RESULT
  70         Process id of the child process on success or -1 on error. If an error
  71         occurred, the global variable errno is set.
  72
  73     NOTES
  74         This function will work only for child processeses notifying parent
  75         process of their death, for example processes created by vfork() call.
  76         If you want to use it for other processes, remember to set the
  77         NP_NotifyOnDeath tag value to TRUE during child process creation.
  78
  79     EXAMPLE
  80
  81     BUGS
  82
  83     SEE ALSO
  84         wait()
  85
  86     INTERNALS
  87         Since POSIX signals are not yet implemented, WIFSIGNALED, WIFSTOPPED
  88         and WIFCONTINUED macros always return 0. WIFEXITED always returns 1.
  89
  90         The et_UniqueID field of the ETask structure is used as process id.
  91
  92 ******************************************************************************/
  93 {
  94     struct ETask *et;
  95     ULONG tid = pid;
  96     pid_t ret = -1;
  97     int exchildno;
  98
  99     D(bug("waitpid(%d, %p, %d)\n", pid, status, options));
 100
 101     et = GetETask(FindTask(NULL));
 102     if(!et)
 103     {
 104         /* only ETasks are fertile */
 105         errno = ECHILD;
 106         return -1;
 107     }
 108
 109     if (pid < -1 || pid == 0)
 110     {
 111         /* process groups not yet supported */
 112         errno = EINVAL;
 113         return -1;
 114     }
 115
 116     if (pid == -1)
 117         tid = 0;
 118
 119     if(tid != 0 && ChildStatus(tid) == CHILD_NOTFOUND)
 120     {
 121         /* error if there's no such child */
 122         errno = ECHILD;
 123         return -1;
 124     }
 125
 126     if (options & ~WNOHANG)
 127     {
 128         /* option not yet supported */
 129         errno = EINVAL;
 130         return -1;
 131     }
 132
 133     /* not very pretty, perhaps we need a function for counting dead
 134        children? */
 135     ListLength(&et->et_TaskMsgPort.mp_MsgList, exchildno);
 136     if ((options & WNOHANG) && (
 137         (tid != 0 && ChildStatus(tid) != CHILD_EXITED) ||
 138         (tid == 0 && exchildno == 0)
 139     ))
 140     {
 141         D(bug("waitpid: no dead children\n"));
 142         /* no dead children atm */
 143         return 0;
 144     }
 145
 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 }