/*********************************************************************** * * * This software is part of the ast package * * Copyright (c) 1985-2007 AT&T Knowledge Ventures * * and is licensed under the * * Common Public License, Version 1.0 * * by AT&T Knowledge Ventures * * * * A copy of the License is available at * * http://www.opensource.org/licenses/cpl1.0.txt * * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * * * * Information and Software Systems Research * * AT&T Research * * Florham Park NJ * * * * Glenn Fowler * * David Korn * * Phong Vo * * * ***********************************************************************/ #pragma prototyped /* * POSIX waitpid() * * pid < -1 WUNTRACED may not be fully supported * process group specifics ignored by non-{waitpid,wait4} */ #include #include #if _lib_waitpid NoN(waitpid) #else #if _lib_wait4 struct rusage; extern int wait4(int, int*, int, struct rusage*); pid_t waitpid(pid_t pid, int* status, int flags) { return(wait4(pid, status, flags, NiL)); } #else #undef SIGCLD #if _lib_wait3 extern int wait3(int*, int, struct rusage*); #else #if _lib_wait2 #define wait3(s,f,u) wait2(s,f) extern int wait2(int*, int); #else #include #define wait3(s,f,u) wait(s) static int caught; static void catch(sig) int sig; { NoP(sig); caught = 1; } #endif #endif #include struct zombie { struct zombie* next; int status; pid_t pid; }; pid_t waitpid(pid_t pid, int* status, int flags) { register struct zombie* zp; register struct zombie* pp; register int p; int s; #if !_lib_wait2 && !_lib_wait3 #if !defined(SIGCLD) int n; int oerrno; #endif Sig_handler_t handler; #endif static struct zombie* zombies; pp = 0; zp = zombies; while (zp) { if (zp->pid >= 0 && (zp->pid == pid || pid <= 0)) { if (pp) pp->next = zp->next; else zombies = zp->next; if (status) *status = zp->status; pid = zp->pid; free(zp); return(pid); } } if (pid > 0 && kill(pid, 0) < 0) return(-1); for (;;) { #if !_lib_wait2 && !_lib_wait3 #if !defined(SIGCLD) oerrno = errno; #endif if (flags & WNOHANG) { caught = 0; #if defined(SIGCLD) handler = signal(SIGCLD, catch); if (!caught) { signal(SIGCLD, handler); return(0); } #else #if defined(SIGALRM) handler = signal(SIGALRM, catch); n = alarm(1); #endif #endif } #endif p = wait3(&s, flags, NiL); #if !_lib_wait3 #if !_lib_wait2 #if defined(SIGCLD) if (flags & WNOHANG) signal(SIGCLD, handler); #else #if defined(SIGALRM) if (flags & WNOHANG) { if (n == 0 && !caught || n == 1) alarm(n); else if (n > 1) alarm(n - caught); signal(SIGALRM, handler); } if (p == -1 && errno == EINTR) { errno = oerrno; p = 0; s = 0; } #endif #endif #else if (p == -1 && errno == EINVAL && (flags & ~WNOHANG)) p = wait3(&s, flags & WNOHANG, NiL); #endif #endif if (p <= 0) { if (p == 0 && status) *status = s; return(p); } if (pid <= 0 || p == pid) { if (status) *status = s; return(p); } if (!(zp = newof(0, struct zombie, 1, 0))) return(-1); zp->pid = p; zp->status = s; zp->next = zombies; zombies = zp; } /*NOTREACHED*/ } #endif #endif