/*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $Id: jobs.c,v 1.12 1997/02/22 13:58:29 peter Exp $ */ #ifndef lint static char const sccsid[] = "@(#)jobs.c 8.5 (Berkeley) 5/4/95"; #endif /* not lint */ #include #include #include #include #include #include #include #ifdef BSD #include #include #include #endif #include #include "shell.h" #if JOBS #if OLD_TTY_DRIVER #include "sgtty.h" #else #include #endif #undef CEOF /* syntax.h redefines this */ #endif #include "redir.h" #include "show.h" #include "main.h" #include "parser.h" #include "nodes.h" #include "jobs.h" #include "options.h" #include "trap.h" #include "syntax.h" #include "input.h" #include "output.h" #include "memalloc.h" #include "error.h" #include "mystring.h" struct job *jobtab; /* array of jobs */ int njobs; /* size of array */ MKINIT short backgndpid = -1; /* pid of last background process */ #if JOBS int initialpgrp; /* pgrp of shell on invocation */ short curjob; /* current job */ #endif #if JOBS STATIC void restartjob __P((struct job *)); #endif STATIC void freejob __P((struct job *)); STATIC struct job *getjob __P((char *)); STATIC int dowait __P((int, struct job *)); #if SYSV STATIC int onsigchild __P((void)); #endif STATIC int waitproc __P((int, int *)); STATIC void cmdtxt __P((union node *)); STATIC void cmdputs __P((char *)); /* * Turn job control on and off. * * Note: This code assumes that the third arg to ioctl is a character * pointer, which is true on Berkeley systems but not System V. Since * System V doesn't have job control yet, this isn't a problem now. */ MKINIT int jobctl; #if JOBS void setjobctl(on) int on; { #ifdef OLD_TTY_DRIVER int ldisc; #endif if (on == jobctl || rootshell == 0) return; if (on) { do { /* while we are in the background */ #ifdef OLD_TTY_DRIVER if (ioctl(2, TIOCGPGRP, (char *)&initialpgrp) < 0) { #else initialpgrp = tcgetpgrp(2); if (initialpgrp < 0) { #endif out2str("sh: can't access tty; job control turned off\n"); mflag = 0; return; } if (initialpgrp == -1) initialpgrp = getpgrp(); else if (initialpgrp != getpgrp()) { killpg(initialpgrp, SIGTTIN); continue; } } while (0); #ifdef OLD_TTY_DRIVER if (ioctl(2, TIOCGETD, (char *)&ldisc) < 0 || ldisc != NTTYDISC) { out2str("sh: need new tty driver to run job control; job control turned off\n"); mflag = 0; return; } #endif setsignal(SIGTSTP); setsignal(SIGTTOU); setsignal(SIGTTIN); setpgid(0, rootpid); #ifdef OLD_TTY_DRIVER ioctl(2, TIOCSPGRP, (char *)&rootpid); #else tcsetpgrp(2, rootpid); #endif } else { /* turning job control off */ setpgid(0, initialpgrp); #ifdef OLD_TTY_DRIVER ioctl(2, TIOCSPGRP, (char *)&initialpgrp); #else tcsetpgrp(2, initialpgrp); #endif setsignal(SIGTSTP); setsignal(SIGTTOU); setsignal(SIGTTIN); } jobctl = on; } #endif #ifdef mkinit INCLUDE SHELLPROC { backgndpid = -1; #if JOBS jobctl = 0; #endif } #endif #if JOBS int fgcmd(argc, argv) int argc; char **argv; { struct job *jp; int pgrp; int status; jp = getjob(argv[1]); if (jp->jobctl == 0) error("job not created under job control"); pgrp = jp->ps[0].pid; #ifdef OLD_TTY_DRIVER ioctl(2, TIOCSPGRP, (char *)&pgrp); #else tcsetpgrp(2, pgrp); #endif restartjob(jp); INTOFF; status = waitforjob(jp); INTON; return status; } int bgcmd(argc, argv) int argc; char **argv; { struct job *jp; do { jp = getjob(*++argv); if (jp->jobctl == 0) error("job not created under job control"); restartjob(jp); } while (--argc > 1); return 0; } STATIC void restartjob(jp) struct job *jp; { struct procstat *ps; int i; if (jp->state == JOBDONE) return; INTOFF; killpg(jp->ps[0].pid, SIGCONT); for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) { if ((ps->status & 0377) == 0177) { ps->status = -1; jp->state = 0; } } INTON; } #endif int jobscmd(argc, argv) int argc; char **argv; { showjobs(0); return 0; } /* * Print a list of jobs. If "change" is nonzero, only print jobs whose * statuses have changed since the last call to showjobs. * * If the shell is interrupted in the process of creating a job, the * result may be a job structure containing zero processes. Such structures * will be freed here. */ void showjobs(change) int change; { int jobno; int procno; int i; struct job *jp; struct procstat *ps; int col; char s[64]; TRACE(("showjobs(%d) called\n", change)); while (dowait(0, (struct job *)NULL) > 0); for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) { if (! jp->used) continue; if (jp->nprocs == 0) { freejob(jp); continue; } if (change && ! jp->changed) continue; procno = jp->nprocs; for (ps = jp->ps ; ; ps++) { /* for each process */ if (ps == jp->ps) fmtstr(s, 64, "[%d] %d ", jobno, ps->pid); else fmtstr(s, 64, " %d ", ps->pid); out1str(s); col = strlen(s); s[0] = '\0'; if (ps->status == -1) { /* don't print anything */ } else if ((ps->status & 0xFF) == 0) { fmtstr(s, 64, "Exit %d", ps->status >> 8); } else { i = ps->status; #if JOBS if ((i & 0xFF) == 0177) i >>= 8; #endif if ((i & 0x7F) < NSIG && sys_siglist[i & 0x7F]) scopy(sys_siglist[i & 0x7F], s); else fmtstr(s, 64, "Signal %d", i & 0x7F); if (i & 0x80) strcat(s, " (core dumped)"); } out1str(s); col += strlen(s); do { out1c(' '); col++; } while (col < 30); out1str(ps->cmd); out1c('\n'); if (--procno <= 0) break; } jp->changed = 0; if (jp->state == JOBDONE) { freejob(jp); } } } /* * Mark a job structure as unused. */ STATIC void freejob(jp) struct job *jp; { struct procstat *ps; int i; INTOFF; for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) { if (ps->cmd != nullstr) ckfree(ps->cmd); } if (jp->ps != &jp->ps0) ckfree(jp->ps); jp->used = 0; #if JOBS if (curjob == jp - jobtab + 1) curjob = 0; #endif INTON; } int waitcmd(argc, argv) int argc; char **argv; { struct job *job; int status; struct job *jp; if (argc > 1) { job = getjob(argv[1]); } else { job = NULL; } for (;;) { /* loop until process terminated or stopped */ if (job != NULL) { if (job->state) { status = job->ps[job->nprocs - 1].status; if ((status & 0xFF) == 0) status = status >> 8 & 0xFF; #if JOBS else if ((status & 0xFF) == 0177) status = (status >> 8 & 0x7F) + 128; #endif else status = (status & 0x7F) + 128; if (! iflag) freejob(job); return status; } } else { for (jp = jobtab ; ; jp++) { if (jp >= jobtab + njobs) { /* no running procs */ return 0; } if (jp->used && jp->state == 0) break; } } dowait(1, (struct job *)NULL); } } int jobidcmd(argc, argv) int argc; char **argv; { struct job *jp; int i; jp = getjob(argv[1]); for (i = 0 ; i < jp->nprocs ; ) { out1fmt("%d", jp->ps[i].pid); out1c(++i < jp->nprocs? ' ' : '\n'); } return 0; } /* * Convert a job name to a job structure. */ STATIC struct job * getjob(name) char *name; { int jobno; struct job *jp; int pid; int i; if (name == NULL) { #if JOBS currentjob: if ((jobno = curjob) == 0 || jobtab[jobno - 1].used == 0) error("No current job"); return &jobtab[jobno - 1]; #else error("No current job"); #endif } else if (name[0] == '%') { if (is_digit(name[1])) { jobno = number(name + 1); if (jobno > 0 && jobno <= njobs && jobtab[jobno - 1].used != 0) return &jobtab[jobno - 1]; #if JOBS } else if (name[1] == '%' && name[2] == '\0') { goto currentjob; #endif } else { struct job *found = NULL; for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) { if (jp->used && jp->nprocs > 0 && prefix(name + 1, jp->ps[0].cmd)) { if (found) error("%s: ambiguous", name); found = jp; } } if (found) return found; } } else if (is_number(name)) { pid = number(name); for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) { if (jp->used && jp->nprocs > 0 && jp->ps[jp->nprocs - 1].pid == pid) return jp; } } error("No such job: %s", name); /*NOTREACHED*/ return NULL; } /* * Return a new job structure, */ struct job * makejob(node, nprocs) union node *node; int nprocs; { int i; struct job *jp; for (i = njobs, jp = jobtab ; ; jp++) { if (--i < 0) { INTOFF; if (njobs == 0) { jobtab = ckmalloc(4 * sizeof jobtab[0]); } else { jp = ckmalloc((njobs + 4) * sizeof jobtab[0]); memcpy(jp, jobtab, njobs * sizeof jp[0]); /* Relocate `ps' pointers */ for (i = 0; i < njobs; i++) if (jp[i].ps == &jobtab[i].ps0) jp[i].ps = &jp[i].ps0; ckfree(jobtab); jobtab = jp; } jp = jobtab + njobs; for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0); INTON; break; } if (jp->used == 0) break; } INTOFF; jp->state = 0; jp->used = 1; jp->changed = 0; jp->nprocs = 0; #if JOBS jp->jobctl = jobctl; #endif if (nprocs > 1) { jp->ps = ckmalloc(nprocs * sizeof (struct procstat)); } else { jp->ps = &jp->ps0; } INTON; TRACE(("makejob(0x%lx, %d) returns %%%d\n", (long)node, nprocs, jp - jobtab + 1)); return jp; } /* * Fork of a subshell. If we are doing job control, give the subshell its * own process group. Jp is a job structure that the job is to be added to. * N is the command that will be evaluated by the child. Both jp and n may * be NULL. The mode parameter can be one of the following: * FORK_FG - Fork off a foreground process. * FORK_BG - Fork off a background process. * FORK_NOJOB - Like FORK_FG, but don't give the process its own * process group even if job control is on. * * When job control is turned off, background processes have their standard * input redirected to /dev/null (except for the second and later processes * in a pipeline). */ int forkshell(jp, n, mode) union node *n; struct job *jp; int mode; { int pid; int pgrp; TRACE(("forkshell(%%%d, 0x%lx, %d) called\n", jp - jobtab, (long)n, mode)); INTOFF; pid = fork(); if (pid == -1) { TRACE(("Fork failed, errno=%d\n", errno)); INTON; error("Cannot fork"); } if (pid == 0) { struct job *p; int wasroot; int i; TRACE(("Child shell %d\n", getpid())); wasroot = rootshell; rootshell = 0; for (i = njobs, p = jobtab ; --i >= 0 ; p++) if (p->used) freejob(p); closescript(); INTON; clear_traps(); #if JOBS jobctl = 0; /* do job control only in root shell */ if (wasroot && mode != FORK_NOJOB && mflag) { if (jp == NULL || jp->nprocs == 0) pgrp = getpid(); else pgrp = jp->ps[0].pid; if (setpgid(0, pgrp) == 0 && mode == FORK_FG) { /*** this causes superfluous TIOCSPGRPS ***/ #ifdef OLD_TTY_DRIVER if (ioctl(2, TIOCSPGRP, (char *)&pgrp) < 0) error("TIOCSPGRP failed, errno=%d", errno); #else if (tcsetpgrp(2, pgrp) < 0) error("tcsetpgrp failed, errno=%d", errno); #endif } setsignal(SIGTSTP); setsignal(SIGTTOU); } else if (mode == FORK_BG) { ignoresig(SIGINT); ignoresig(SIGQUIT); if ((jp == NULL || jp->nprocs == 0) && ! fd0_redirected_p ()) { close(0); if (open("/dev/null", O_RDONLY) != 0) error("Can't open /dev/null"); } } #else if (mode == FORK_BG) { ignoresig(SIGINT); ignoresig(SIGQUIT); if ((jp == NULL || jp->nprocs == 0) && ! fd0_redirected_p ()) { close(0); if (open("/dev/null", O_RDONLY) != 0) error("Can't open /dev/null"); } } #endif if (wasroot && iflag) { setsignal(SIGINT); setsignal(SIGQUIT); setsignal(SIGTERM); } return pid; } if (rootshell && mode != FORK_NOJOB && mflag) { if (jp == NULL || jp->nprocs == 0) pgrp = pid; else pgrp = jp->ps[0].pid; setpgid(pid, pgrp); } if (mode == FORK_BG) backgndpid = pid; /* set $! */ if (jp) { struct procstat *ps = &jp->ps[jp->nprocs++]; ps->pid = pid; ps->status = -1; ps->cmd = nullstr; if (iflag && rootshell && n) ps->cmd = commandtext(n); } INTON; TRACE(("In parent shell: child = %d\n", pid)); return pid; } /* * Wait for job to finish. * * Under job control we have the problem that while a child process is * running interrupts generated by the user are sent to the child but not * to the shell. This means that an infinite loop started by an inter- * active user may be hard to kill. With job control turned off, an * interactive user may place an interactive program inside a loop. If * the interactive program catches interrupts, the user doesn't want * these interrupts to also abort the loop. The approach we take here * is to have the shell ignore interrupt signals while waiting for a * forground process to terminate, and then send itself an interrupt * signal if the child process was terminated by an interrupt signal. * Unfortunately, some programs want to do a bit of cleanup and then * exit on interrupt; unless these processes terminate themselves by * sending a signal to themselves (instead of calling exit) they will * confuse this approach. */ int waitforjob(jp) struct job *jp; { #if JOBS int mypgrp = getpgrp(); #endif int status; int st; INTOFF; TRACE(("waitforjob(%%%d) called\n", jp - jobtab + 1)); while (jp->state == 0) { dowait(1, jp); } #if JOBS if (jp->jobctl) { #ifdef OLD_TTY_DRIVER if (ioctl(2, TIOCSPGRP, (char *)&mypgrp) < 0) error("TIOCSPGRP failed, errno=%d\n", errno); #else if (tcsetpgrp(2, mypgrp) < 0) error("tcsetpgrp failed, errno=%d\n", errno); #endif } if (jp->state == JOBSTOPPED) curjob = jp - jobtab + 1; #endif status = jp->ps[jp->nprocs - 1].status; /* convert to 8 bits */ if ((status & 0xFF) == 0) st = status >> 8 & 0xFF; #if JOBS else if ((status & 0xFF) == 0177) st = (status >> 8 & 0x7F) + 128; #endif else st = (status & 0x7F) + 128; if (! JOBS || jp->state == JOBDONE) freejob(jp); CLEAR_PENDING_INT; if ((status & 0x7F) == SIGINT) kill(getpid(), SIGINT); INTON; return st; } /* * Wait for a process to terminate. */ STATIC int dowait(block, job) int block; struct job *job; { int pid; int status; struct procstat *sp; struct job *jp; struct job *thisjob; int done; int stopped; int core; TRACE(("dowait(%d) called\n", block)); do { pid = waitproc(block, &status); TRACE(("wait returns %d, status=%d\n", pid, status)); } while (pid == -1 && errno == EINTR); if (pid <= 0) return pid; INTOFF; thisjob = NULL; for (jp = jobtab ; jp < jobtab + njobs ; jp++) { if (jp->used) { done = 1; stopped = 1; for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) { if (sp->pid == -1) continue; if (sp->pid == pid) { TRACE(("Changin status of proc %d from 0x%x to 0x%x\n", pid, sp->status, status)); sp->status = status; thisjob = jp; } if (sp->status == -1) stopped = 0; else if ((sp->status & 0377) == 0177) done = 0; } if (stopped) { /* stopped or done */ int state = done? JOBDONE : JOBSTOPPED; if (jp->state != state) { TRACE(("Job %d: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state)); jp->state = state; #if JOBS if (done && curjob == jp - jobtab + 1) curjob = 0; /* no current job */ #endif } } } } INTON; if (! rootshell || ! iflag || (job && thisjob == job)) { #if JOBS if ((status & 0xFF) == 0177) status >>= 8; #endif core = status & 0x80; status &= 0x7F; if (status != 0 && status != SIGINT && status != SIGPIPE) { if (thisjob != job) outfmt(out2, "%d: ", pid); #if JOBS if (status == SIGTSTP && rootshell && iflag) outfmt(out2, "%%%d ", job - jobtab + 1); #endif if (status < NSIG && sys_siglist[status]) out2str(sys_siglist[status]); else outfmt(out2, "Signal %d", status); if (core) out2str(" - core dumped"); out2c('\n'); flushout(&errout); } else { TRACE(("Not printing status: status=%d\n", status)); } } else { TRACE(("Not printing status, rootshell=%d, job=0x%x\n", rootshell, job)); if (thisjob) thisjob->changed = 1; } return pid; } /* * Do a wait system call. If job control is compiled in, we accept * stopped processes. If block is zero, we return a value of zero * rather than blocking. * * System V doesn't have a non-blocking wait system call. It does * have a SIGCLD signal that is sent to a process when one of it's * children dies. The obvious way to use SIGCLD would be to install * a handler for SIGCLD which simply bumped a counter when a SIGCLD * was received, and have waitproc bump another counter when it got * the status of a process. Waitproc would then know that a wait * system call would not block if the two counters were different. * This approach doesn't work because if a process has children that * have not been waited for, System V will send it a SIGCLD when it * installs a signal handler for SIGCLD. What this means is that when * a child exits, the shell will be sent SIGCLD signals continuously * until is runs out of stack space, unless it does a wait call before * restoring the signal handler. The code below takes advantage of * this (mis)feature by installing a signal handler for SIGCLD and * then checking to see whether it was called. If there are any * children to be waited for, it will be. * * If neither SYSV nor BSD is defined, we don't implement nonblocking * waits at all. In this case, the user will not be informed when * a background process until the next time she runs a real program * (as opposed to running a builtin command or just typing return), * and the jobs command may give out of date information. */ #ifdef SYSV STATIC int gotsigchild; STATIC int onsigchild() { gotsigchild = 1; } #endif STATIC int waitproc(block, status) int block; int *status; { #ifdef BSD int flags; #if JOBS flags = WUNTRACED; #else flags = 0; #endif if (block == 0) flags |= WNOHANG; return wait3(status, flags, (struct rusage *)NULL); #else #ifdef SYSV int (*save)(); if (block == 0) { gotsigchild = 0; save = signal(SIGCLD, onsigchild); signal(SIGCLD, save); if (gotsigchild == 0) return 0; } return wait(status); #else if (block == 0) return 0; return wait(status); #endif #endif } /* * return 1 if there are stopped jobs, otherwise 0 */ int job_warning = 0; int stoppedjobs() { int jobno; struct job *jp; if (job_warning) return (0); for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) { if (jp->used == 0) continue; if (jp->state == JOBSTOPPED) { out2str("You have stopped jobs.\n"); job_warning = 2; return (1); } } return (0); } /* * Return a string identifying a command (to be printed by the * jobs command. */ STATIC char *cmdnextc; STATIC int cmdnleft; STATIC void cmdtxt(), cmdputs(); #define MAXCMDTEXT 200 char * commandtext(n) union node *n; { char *name; cmdnextc = name = ckmalloc(MAXCMDTEXT); cmdnleft = MAXCMDTEXT - 4; cmdtxt(n); *cmdnextc = '\0'; return name; } STATIC void cmdtxt(n) union node *n; { union node *np; struct nodelist *lp; char *p; int i; char s[2]; if (n == NULL) return; switch (n->type) { case NSEMI: cmdtxt(n->nbinary.ch1); cmdputs("; "); cmdtxt(n->nbinary.ch2); break; case NAND: cmdtxt(n->nbinary.ch1); cmdputs(" && "); cmdtxt(n->nbinary.ch2); break; case NOR: cmdtxt(n->nbinary.ch1); cmdputs(" || "); cmdtxt(n->nbinary.ch2); break; case NPIPE: for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) { cmdtxt(lp->n); if (lp->next) cmdputs(" | "); } break; case NSUBSHELL: cmdputs("("); cmdtxt(n->nredir.n); cmdputs(")"); break; case NREDIR: case NBACKGND: cmdtxt(n->nredir.n); break; case NIF: cmdputs("if "); cmdtxt(n->nif.test); cmdputs("; then "); cmdtxt(n->nif.ifpart); cmdputs("..."); break; case NWHILE: cmdputs("while "); goto until; case NUNTIL: cmdputs("until "); until: cmdtxt(n->nbinary.ch1); cmdputs("; do "); cmdtxt(n->nbinary.ch2); cmdputs("; done"); break; case NFOR: cmdputs("for "); cmdputs(n->nfor.var); cmdputs(" in ..."); break; case NCASE: cmdputs("case "); cmdputs(n->ncase.expr->narg.text); cmdputs(" in ..."); break; case NDEFUN: cmdputs(n->narg.text); cmdputs("() ..."); break; case NCMD: for (np = n->ncmd.args ; np ; np = np->narg.next) { cmdtxt(np); if (np->narg.next) cmdputs(" "); } for (np = n->ncmd.redirect ; np ; np = np->nfile.next) { cmdputs(" "); cmdtxt(np); } break; case NARG: cmdputs(n->narg.text); break; case NTO: p = ">"; i = 1; goto redir; case NAPPEND: p = ">>"; i = 1; goto redir; case NTOFD: p = ">&"; i = 1; goto redir; case NFROM: p = "<"; i = 0; goto redir; case NFROMFD: p = "<&"; i = 0; goto redir; redir: if (n->nfile.fd != i) { s[0] = n->nfile.fd + '0'; s[1] = '\0'; cmdputs(s); } cmdputs(p); if (n->type == NTOFD || n->type == NFROMFD) { s[0] = n->ndup.dupfd + '0'; s[1] = '\0'; cmdputs(s); } else { cmdtxt(n->nfile.fname); } break; case NHERE: case NXHERE: cmdputs("<<..."); break; default: cmdputs("???"); break; } } STATIC void cmdputs(s) char *s; { char *p, *q; char c; int subtype = 0; if (cmdnleft <= 0) return; p = s; q = cmdnextc; while ((c = *p++) != '\0') { if (c == CTLESC) *q++ = *p++; else if (c == CTLVAR) { *q++ = '$'; if (--cmdnleft > 0) *q++ = '{'; subtype = *p++; } else if (c == '=' && subtype != 0) { *q++ = "}-+?="[(subtype & VSTYPE) - VSNORMAL]; subtype = 0; } else if (c == CTLENDVAR) { *q++ = '}'; } else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) cmdnleft++; /* ignore it */ else *q++ = c; if (--cmdnleft <= 0) { *q++ = '.'; *q++ = '.'; *q++ = '.'; break; } } cmdnextc = q; }