1  /* Wait for process to change state.  Linux version.
       2     Copyright (C) 2019-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <sys/wait.h>
      20  #include <sys/resource.h>
      21  #include <sys/types.h>
      22  #include <sysdep-cancel.h>
      23  #include <tv32-compat.h>
      24  
      25  pid_t
      26  __wait4_time64 (pid_t pid, int *stat_loc, int options, struct __rusage64 *usage)
      27  {
      28  #ifdef __NR_wait4
      29  # if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
      30    return SYSCALL_CANCEL (wait4, pid, stat_loc, options, usage);
      31  # else
      32    pid_t ret;
      33    struct __rusage32 usage32;
      34  
      35    ret = SYSCALL_CANCEL (wait4, pid, stat_loc, options,
      36                          usage != NULL ? &usage32 : NULL);
      37  
      38    if (ret > 0 && usage != NULL)
      39      rusage32_to_rusage64 (&usage32, usage);
      40  
      41    return ret;
      42  # endif
      43  #elif defined (__ASSUME_WAITID_PID0_P_PGID)
      44    idtype_t idtype = P_PID;
      45  
      46    if (pid < -1)
      47      {
      48        idtype = P_PGID;
      49        pid *= -1;
      50      }
      51    else if (pid == -1)
      52      idtype = P_ALL;
      53    else if (pid == 0)
      54      idtype = P_PGID;
      55  
      56    options |= WEXITED;
      57  
      58    siginfo_t infop;
      59  
      60  # if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
      61    if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, usage) < 0)
      62      return -1;
      63  # else
      64    {
      65      struct __rusage32 usage32;
      66      if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, &usage32) < 0)
      67        return -1;
      68      if (usage != NULL)
      69        rusage32_to_rusage64 (&usage32, usage);
      70    }
      71  # endif
      72  
      73    if (stat_loc)
      74      {
      75        switch (infop.si_code)
      76          {
      77          case CLD_EXITED:
      78            *stat_loc = W_EXITCODE (infop.si_status, 0);
      79            break;
      80          case CLD_DUMPED:
      81            *stat_loc = WCOREFLAG | infop.si_status;
      82  	  break;
      83          case CLD_KILLED:
      84            *stat_loc = infop.si_status;
      85            break;
      86          case CLD_TRAPPED:
      87          case CLD_STOPPED:
      88            *stat_loc = W_STOPCODE (infop.si_status);
      89            break;
      90          case CLD_CONTINUED:
      91            *stat_loc = __W_CONTINUED;
      92            break;
      93  	default:
      94  	  *stat_loc = 0;
      95  	  break;
      96          }
      97      }
      98  
      99    return infop.si_pid;
     100  #else
     101  /* Linux waitid prior kernel 5.4 does not support waiting for the current
     102     process.  It is possible to emulate wait4 it by calling getpgid for
     103     PID 0, however, it would require an additional syscall and it is inherent
     104     racy: after the current process group is received and before it is passed
     105     to waitid a signal could arrive causing the current process group to
     106     change.  */
     107  # error "The kernel ABI does not provide a way to implement wait4"
     108  #endif
     109  }
     110  
     111  #if __TIMESIZE != 64
     112  libc_hidden_def (__wait4_time64)
     113  
     114  pid_t
     115  __wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
     116  {
     117    pid_t ret;
     118    struct __rusage64 usage64;
     119  
     120    ret = __wait4_time64 (pid, stat_loc, options,
     121                          usage != NULL ? &usage64 : NULL);
     122  
     123    if (ret > 0 && usage != 0)
     124      rusage64_to_rusage (&usage64, usage);
     125  
     126    return ret;
     127  }
     128  #endif
     129  libc_hidden_def (__wait4);
     130  weak_alias (__wait4, wait4)