common/sh/subshell.c

	subshell.c revision da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/***********************************************************************
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                                                                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*               This software is part of the ast package               *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*           Copyright (c) 1982-2007 AT&T Knowledge Ventures            *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                      and is licensed under the                       *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                  Common Public License, Version 1.0                  *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                      by AT&T Knowledge Ventures                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                                                                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                A copy of the License is available at                 *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*            http://www.opensource.org/licenses/cpl1.0.txt             *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                                                                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*              Information and Software Systems Research               *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                            AT&T Research                             *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                           Florham Park NJ                            *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                                                                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                  David Korn <dgk@research.att.com>                   *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*                                                                      *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin***********************************************************************/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#pragma prototyped
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *   Create and manage subshells avoiding forks when possible
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *   David Korn
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *   AT&T Labs
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "defs.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    <ls.h>
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "io.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "fault.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "shnodes.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "shlex.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "jobs.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "variables.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include    "path.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifndef PIPE_BUF
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#   define PIPE_BUF 512
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * Note that the following structure must be the same
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * size as the Dtlink_t structure
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstruct Link
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct Link *next;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Namval_t    *node;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin};
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * The following structure is used for command substitution and (...)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic struct subshell
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct subshell *prev;  /* previous subshell data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct subshell *pipe;  /* subshell where output goes to pipe on fork */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Dt_t        *var;   /* variable table at time of subshell */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct Link *svar;  /* save shell variable table */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Dt_t        *sfun;  /* function scope for subshell */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Dt_t        *salias;/* alias scope for subshell */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifdef PATH_BFPATH
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Pathcomp_t  *pathlist; /* for PATH variable */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if (ERROR_VERSION >= 20030214L)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct Error_context_s *errcontext;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct errorcontext *errcontext;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Shopt_t     options;/* save shell options */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    pid_t       subpid; /* child process id */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Sfio_t* saveout;/*saved standard output */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    char        *pwd;   /* present working directory */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    const char  *shpwd; /* saved pointer to sh.pwd */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    void        *jobs;  /* save job info */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    mode_t      mask;   /* saved umask */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    short       tmpfd;  /* saved tmp file descriptor */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    short       pipefd; /* read fd if pipe is created */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    char        jobcontrol;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    char        monitor;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    unsigned char   fdstatus;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int     fdsaved; /* bit make for saved files */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int     bckpid;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin} *subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic int subenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * This routine will turn the sftmp() file into a real /tmp file or pipe
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * if the /tmp file create fails
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinvoid    sh_subtmpfile(void)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(sfset(sfstdout,0,0)&SF_STRING)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        register int fd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        register struct checkpt *pp = (struct checkpt*)sh.jmplist;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        register struct subshell *sp = subshell_data->pipe;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* save file descriptor 1 if open */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if((sp->tmpfd = fd = fcntl(1,F_DUPFD,10)) >= 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            fcntl(fd,F_SETFD,FD_CLOEXEC);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh.fdstatus[fd] = sh.fdstatus[1]|IOCLEX;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            close(1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else if(errno!=EBADF)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            errormsg(SH_DICT,ERROR_system(1),e_toomany);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* popping a discipline forces a /tmp file create */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sfdisc(sfstdout,SF_POPDISC);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if((fd=sffileno(sfstdout))<0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* unable to create the /tmp file so use a pipe */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            int fds[2];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            Sfoff_t off;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_pipe(fds);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->pipefd = fds[0];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_fcntl(sp->pipefd,F_SETFD,FD_CLOEXEC);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* write the data to the pipe */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(off = sftell(sfstdout))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                write(fds[1],sfsetbuf(sfstdout,(Void_t*)sfstdout,0),(size_t)off);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfclose(sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if((sh_fcntl(fds[1],F_DUPFD, 1)) != 1)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                errormsg(SH_DICT,ERROR_system(1),e_file+4);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_close(fds[1]);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh.fdstatus[fd] = IOREAD|IOWRITE;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfsync(sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(fd==1)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                fcntl(1,F_SETFD,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                sfsetfd(sfstdout,1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                sh.fdstatus[1] = sh.fdstatus[fd];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                sh.fdstatus[fd] = IOCLOSE;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_iostream(1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sfset(sfstdout,SF_SHARE|SF_PUBLIC,1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sfpool(sfstdout,sh.outpool,SF_WRITE);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(pp && pp->olist  && pp->olist->strm == sfstdout)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            pp->olist->strm = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * This routine creates a temp file if necessary and creates a subshell.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * The parent routine longjmps back to sh_subshell()
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * The child continues possibly with its standard output replaced by temp file
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinvoid sh_subfork(void)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    pid_t pid;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    /* see whether inside $(...) */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(sp->pipe)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_subtmpfile();
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(pid = sh_fork(0,NIL(int*)))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* this is the parent part of the fork */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->subpid==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->subpid = pid;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        siglongjmp(*sh.jmplist,SH_JMPSUB);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        int16_t subshell;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* this is the child part of the fork */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* setting subpid to 1 causes subshell to exit when reached */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_onstate(SH_FORKED);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_onstate(SH_NOLOG);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_offstate(SH_MONITOR);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        subshell_data = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        subshell = sh.subshell = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        nv_putval(SH_SUBSHELLNOD, (char*)&subshell, NV_INT16);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->subpid=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * This routine will make a copy of the given node in the
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * layer created by the most recent subshell_fork if the
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * node hasn't already been copied
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinNamval_t *sh_assignok(register Namval_t *np,int add)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register Namval_t *mp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct Link *lp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = (struct subshell*)subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int save;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    /* don't bother with this */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!sp->shpwd || (nv_isnull(np) && !add))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        return(np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    /* don't bother to save if in newer scope */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(nv_search((char*)np,sp->var,HASH_BUCKET)!=np)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        return(np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    for(lp=subshell_data->svar; lp; lp = lp->next)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(lp->node==np)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            return(np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    mp =  newof(0,Namval_t,1,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    lp = (struct Link*)mp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    lp->node = np;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    lp->next = subshell_data->svar;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    subshell_data->svar = lp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    save = sh.subshell;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sh.subshell = 0;;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    nv_clone(np,mp,NV_NOFREE);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sh.subshell = save;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    return(np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * restore the variables
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic void nv_restore(struct subshell *sp)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct Link *lp, *lq;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register Namval_t *mp, *np;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    const char *save = sp->shpwd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->shpwd = 0;  /* make sure sh_assignok doesn't save with nv_unset() */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    for(lp=sp->svar; lp; lp=lq)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        np = (Namval_t*)lp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        mp = lp->node;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        lq = lp->next;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(nv_isarray(mp))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin             nv_putsub(mp,NIL(char*),ARRAY_SCAN);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        _nv_unset(mp,NV_RDONLY);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        nv_setsize(mp,nv_size(np));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(!nv_isattr(np,NV_MINIMAL) || nv_isattr(np,NV_EXPORT))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            mp->nvenv = np->nvenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        mp->nvfun = np->nvfun;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        mp->nvflag = np->nvflag;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if((mp==nv_scoped(PATHNOD)) || (mp==nv_scoped(IFSNOD)))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            nv_putval(mp, np->nvalue.cp,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            mp->nvalue.cp = np->nvalue.cp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        np->nvfun = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(nv_isattr(mp,NV_EXPORT))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            char *name = nv_name(mp);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_envput(sh.env,mp);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(*name=='_' && strcmp(name,"_AST_FEATURES")==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                astconf(NiL, NiL, NiL);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else if(nv_isattr(np,NV_EXPORT))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            env_delete(sh.env,nv_name(mp));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        free((void*)np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->shpwd=save;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * return pointer to alias tree
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * create new one if in a subshell and one doesn't exist and create is non-zero
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinDt_t *sh_subaliastree(int create)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!sp || sh.curenv==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        return(sh.alias_tree);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!sp->salias && create)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->salias = dtopen(&_Nvdisc,Dtoset);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        dtview(sp->salias,sh.alias_tree);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh.alias_tree = sp->salias;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    return(sp->salias);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * return pointer to function tree
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * create new one if in a subshell and one doesn't exist and create is non-zero
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinDt_t *sh_subfuntree(int create)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!sp || sh.curenv==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        return(sh.fun_tree);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!sp->sfun && create)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->sfun = dtopen(&_Nvdisc,Dtoset);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        dtview(sp->sfun,sh.fun_tree);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh.fun_tree = sp->sfun;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    return(sp->sfun);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinstatic void table_unset(register Dt_t *root)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register Namval_t *np,*nq;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    for(np=(Namval_t*)dtfirst(root);np;np=nq)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        _nv_unset(np,NV_RDONLY);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        nq = (Namval_t*)dtnext(root,np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        dtdelete(root,np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        free((void*)np);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinint sh_subsavefd(register int fd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register int old=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(sp)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        old = !(sp->fdsaved&(1<<(fd-1)));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->fdsaved |= (1<<(fd-1));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    return(old);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/*
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * Run command tree <t> in a virtual sub-shell
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * If comsub is not null, then output will be placed in temp file (or buffer)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * If comsub is not null, the return value will be a stream consisting of
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * output of command <t>.  Otherwise, NULL will be returned.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinSfio_t *sh_subshell(Shnode_t *t, int flags, int comsub)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Shell_t *shp = &sh;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct subshell sub_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    register struct subshell *sp = &sub_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int jmpval,nsig;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int savecurenv = shp->curenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    int16_t subshell;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    char *savsig;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    Sfio_t *iop=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct checkpt buff;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct sh_scoped savst;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    struct dolnod   *argsav=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    memset((char*)sp, 0, sizeof(*sp));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sfsync(shp->outpool);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    argsav = sh_arguse();
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(shp->curenv==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        subshell_data=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        subenv = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->curenv = ++subenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    savst = shp->st;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sh_pushcontext(&buff,SH_JMPSUB);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    subshell = shp->subshell+1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    nv_putval(SH_SUBSHELLNOD, (char*)&subshell, NV_INT16);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->subshell = subshell;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->prev = subshell_data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    subshell_data = sp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->errcontext = &buff.err;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->var = shp->var_tree;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->options = shp->options;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->jobs = job_subsave();
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifdef PATH_BFPATH
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    /* make sure initialization has occurred */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!shp->pathlist)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        path_get(".");
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->pathlist = path_dup((Pathcomp_t*)shp->pathlist);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!shp->pwd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        path_pwd(0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sp->bckpid = shp->bckpid;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(!comsub || !sh_isoption(SH_SUBSHARE))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->shpwd = shp->pwd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->pwd = (shp->pwd?strdup(shp->pwd):0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sp->mask = shp->mask;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* save trap table */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->st.otrapcom = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if((nsig=shp->st.trapmax*sizeof(char*))>0 || shp->st.trapcom[0])
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            nsig += sizeof(char*);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            memcpy(savsig=malloc(nsig),(char*)&shp->st.trapcom[0],nsig);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* this nonsense needed for $(trap) */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            shp->st.otrapcom = (char**)savsig;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_sigreset(0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    jmpval = sigsetjmp(buff.buff,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(jmpval==0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(comsub)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* disable job control */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->jobcontrol = job.jobcontrol;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->monitor = (sh_isstate(SH_MONITOR)!=0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            job.jobcontrol=0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_offstate(SH_MONITOR);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->pipe = sp;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* save sfstdout and status */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->saveout = sfswap(sfstdout,NIL(Sfio_t*));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->fdstatus = shp->fdstatus[1];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->tmpfd = -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->pipefd = -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* use sftmp() file for standard output */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(!(iop = sftmp(PIPE_BUF)))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                sfswap(sp->saveout,sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                errormsg(SH_DICT,ERROR_system(1),e_tmpcreate);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfswap(iop,sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfset(sfstdout,SF_READ,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            shp->fdstatus[1] = IOWRITE;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else if(sp->prev)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sp->pipe = sp->prev->pipe;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            flags &= ~sh_state(SH_NOFORK);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_exec(t,flags);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(jmpval!=SH_JMPSUB && shp->st.trapcom[0] && shp->subshell)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* trap on EXIT not handled by child */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        char *trap=shp->st.trapcom[0];
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->st.trapcom[0] = 0; /* prevent recursion */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->oldexit = shp->exitval;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_trap(trap,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        free(trap);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sh_popcontext(&buff);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(shp->subshell==0)    /* must be child process */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        subshell_data = sp->prev;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(jmpval==SH_JMPSCRIPT)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            siglongjmp(*shp->jmplist,jmpval);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_done(0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(comsub)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /* re-enable job control */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        job.jobcontrol = sp->jobcontrol;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->monitor)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_onstate(SH_MONITOR);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->pipefd>=0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* sftmp() file has been returned into pipe */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            iop = sh_iostream(sp->pipefd);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfdisc(iop,SF_POPDISC);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfclose(sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* move tmp file to iop and restore sfstdout */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            iop = sfswap(sfstdout,NIL(Sfio_t*));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(!iop)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                /* maybe locked try again */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                sfclrlock(sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                iop = sfswap(sfstdout,NIL(Sfio_t*));
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(iop && sffileno(iop)==1)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                int fd=sfsetfd(iop,3);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                if(fd<0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                    errormsg(SH_DICT,ERROR_system(1),e_toomany);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                shp->sftable[fd] = iop;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                fcntl(fd,F_SETFD,FD_CLOEXEC);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                shp->fdstatus[fd] = (shp->fdstatus[1]|IOCLEX);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                shp->fdstatus[1] = IOCLOSE;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sfset(iop,SF_READ,1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sfswap(sp->saveout,sfstdout);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        /*  check if standard output was preserved */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->tmpfd>=0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            close(1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            fcntl(sp->tmpfd,F_DUPFD,1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_close(sp->tmpfd);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->fdstatus[1] = sp->fdstatus;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(sp->subpid)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        job_wait(sp->subpid);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(comsub && iop)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sfseek(iop,(off_t)0,SEEK_SET);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(shp->subshell)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->subshell--;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    subshell = shp->subshell;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    nv_putval(SH_SUBSHELLNOD, (char*)&subshell, NV_INT16);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifdef PATH_BFPATH
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    path_delete((Pathcomp_t*)shp->pathlist);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->pathlist = (void*)sp->pathlist;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    job_subrestore(sp->jobs);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->jobenv = savecurenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->bckpid = sp->bckpid;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(sp->shpwd)   /* restore environment if saved */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->options = sp->options;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        nv_restore(sp);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->salias)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            shp->alias_tree = dtview(sp->salias,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            table_unset(sp->salias);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            dtclose(sp->salias);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->sfun)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            shp->fun_tree = dtview(sp->sfun,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            table_unset(sp->sfun);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            dtclose(sp->sfun);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_sigreset(1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->st = savst;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->curenv = savecurenv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(nsig)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            memcpy((char*)&shp->st.trapcom[0],savsig,nsig);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            free((void*)savsig);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        shp->options = sp->options;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(!shp->pwd || strcmp(sp->pwd,shp->pwd))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            /* restore PWDNOD */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            Namval_t *pwdnod = nv_scoped(PWDNOD);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(shp->pwd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                chdir(shp->pwd=sp->pwd);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifdef PATH_BFPATH
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                path_newdir(shp->pathlist);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(nv_isattr(pwdnod,NV_NOFREE))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                pwdnod->nvalue.cp = (const char*)sp->pwd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else if(sp->shpwd != shp->pwd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            shp->pwd = sp->pwd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            if(PWDNOD->nvalue.cp==sp->shpwd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin                PWDNOD->nvalue.cp = sp->pwd;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            free((void*)sp->pwd);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sp->mask!=shp->mask)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            umask(shp->mask);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    subshell_data = sp->prev;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    sh_argfree(argsav,0);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    shp->trapnote = 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(shp->topfd != buff.topfd)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        sh_iorestore(buff.topfd|IOSUBSHELL,jmpval);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    if(shp->exitval > SH_EXITSIG)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    {
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        int sig = shp->exitval&SH_EXITMASK;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin        if(sig==SIGINT || sig== SIGQUIT)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin            sh_fault(sig);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin    return(iop);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}