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freebsd-skq/bin/sh/jobs.c
Jilles Tjoelker 6bc7175f31 sh: Fix double INTON with vfork 
The shell maintains a count of the number of times SIGINT processing has
been disabled via INTOFF, so SIGINT processing resumes when all disables
have enabled again (INTON).

If an error occurs in a vfork() child, the processing of the error enables
SIGINT processing again, and the INTON in vforkexecshell() causes the count
to become negative.

As a result, a later INTOFF may not actually disable SIGINT processing. This
might cause memory corruption if a SIGINT arrives at an inopportune time. As
of r360452, it causes the shell to abort when it would unsafely allocate or
free memory in certain ways.

Note that various places such as errors in non-special builtins
unconditionally reset the count to 0, so the problem might still not always
be visible.

PR:		246497
Reported by:	jbeich
MFC after:	2 weeks
2020-05-16 16:29:23 +00:00

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/*-
* 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. 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)jobs.c 8.5 (Berkeley) 5/4/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include "shell.h"
#if JOBS
#include <termios.h>
#undef CEOF /* syntax.h redefines this */
#endif
#include "redir.h"
#include "exec.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"
#include "var.h"
#include "builtins.h"
#include "eval.h"
/*
* A job structure contains information about a job. A job is either a
* single process or a set of processes contained in a pipeline. In the
* latter case, pidlist will be non-NULL, and will point to a -1 terminated
* array of pids.
*/
struct procstat {
pid_t pid; /* process id */
int status; /* status flags (defined above) */
char *cmd; /* text of command being run */
};
/* states */
#define JOBSTOPPED 1 /* all procs are stopped */
#define JOBDONE 2 /* all procs are completed */
struct job {
struct procstat ps0; /* status of process */
struct procstat *ps; /* status or processes when more than one */
short nprocs; /* number of processes */
pid_t pgrp; /* process group of this job */
char state; /* true if job is finished */
char used; /* true if this entry is in used */
char changed; /* true if status has changed */
char foreground; /* true if running in the foreground */
char remembered; /* true if $! referenced */
char pipefail; /* pass any non-zero status */
#if JOBS
char jobctl; /* job running under job control */
struct job *next; /* job used after this one */
#endif
};
static struct job *jobtab; /* array of jobs */
static int njobs; /* size of array */
static pid_t backgndpid = -1; /* pid of last background process */
static struct job *bgjob = NULL; /* last background process */
#if JOBS
static struct job *jobmru; /* most recently used job list */
static pid_t initialpgrp; /* pgrp of shell on invocation */
#endif
static int ttyfd = -1;
/* mode flags for dowait */
#define DOWAIT_BLOCK 0x1 /* wait until a child exits */
#define DOWAIT_SIG 0x2 /* if DOWAIT_BLOCK, abort on signal */
#define DOWAIT_SIG_TRAP 0x4 /* if DOWAIT_SIG, abort on trapped signal only */
#if JOBS
static void restartjob(struct job *);
#endif
static void freejob(struct job *);
static int waitcmdloop(struct job *);
static struct job *getjob_nonotfound(const char *);
static struct job *getjob(const char *);
pid_t killjob(const char *, int);
static pid_t dowait(int, struct job *);
static void checkzombies(void);
static void cmdtxt(union node *);
static void cmdputs(const char *);
#if JOBS
static void setcurjob(struct job *);
static void deljob(struct job *);
static struct job *getcurjob(struct job *);
#endif
static int getjobstatus(const struct job *);
static void printjobcmd(struct job *);
static void showjob(struct job *, int);
/*
* Turn job control on and off.
*/
static int jobctl;
#if JOBS
static void
jobctl_notty(void)
{
if (ttyfd >= 0) {
close(ttyfd);
ttyfd = -1;
}
if (!iflag) {
setsignal(SIGTSTP);
setsignal(SIGTTOU);
setsignal(SIGTTIN);
jobctl = 1;
return;
}
out2fmt_flush("sh: can't access tty; job control turned off\n");
mflag = 0;
}
void
setjobctl(int on)
{
int i;
if (on == jobctl || rootshell == 0)
return;
if (on) {
if (ttyfd != -1)
close(ttyfd);
if ((ttyfd = open(_PATH_TTY, O_RDWR | O_CLOEXEC)) < 0) {
i = 0;
while (i <= 2 && !isatty(i))
i++;
if (i > 2 ||
(ttyfd = fcntl(i, F_DUPFD_CLOEXEC, 10)) < 0) {
jobctl_notty();
return;
}
}
if (ttyfd < 10) {
/*
* Keep our TTY file descriptor out of the way of
* the user's redirections.
*/
if ((i = fcntl(ttyfd, F_DUPFD_CLOEXEC, 10)) < 0) {
jobctl_notty();
return;
}
close(ttyfd);
ttyfd = i;
}
do { /* while we are in the background */
initialpgrp = tcgetpgrp(ttyfd);
if (initialpgrp < 0) {
jobctl_notty();
return;
}
if (initialpgrp != getpgrp()) {
if (!iflag) {
initialpgrp = -1;
jobctl_notty();
return;
}
kill(0, SIGTTIN);
continue;
}
} while (0);
setsignal(SIGTSTP);
setsignal(SIGTTOU);
setsignal(SIGTTIN);
setpgid(0, rootpid);
tcsetpgrp(ttyfd, rootpid);
} else { /* turning job control off */
setpgid(0, initialpgrp);
if (ttyfd >= 0) {
tcsetpgrp(ttyfd, initialpgrp);
close(ttyfd);
ttyfd = -1;
}
setsignal(SIGTSTP);
setsignal(SIGTTOU);
setsignal(SIGTTIN);
}
jobctl = on;
}
#endif
#if JOBS
int
fgcmd(int argc __unused, char **argv __unused)
{
struct job *jp;
pid_t pgrp;
int status;
nextopt("");
jp = getjob(*argptr);
if (jp->jobctl == 0)
error("job not created under job control");
printjobcmd(jp);
flushout(&output);
pgrp = jp->ps[0].pid;
if (ttyfd >= 0)
tcsetpgrp(ttyfd, pgrp);
restartjob(jp);
jp->foreground = 1;
INTOFF;
status = waitforjob(jp, (int *)NULL);
INTON;
return status;
}
int
bgcmd(int argc __unused, char **argv __unused)
{
struct job *jp;
nextopt("");
do {
jp = getjob(*argptr);
if (jp->jobctl == 0)
error("job not created under job control");
if (jp->state == JOBDONE)
continue;
restartjob(jp);
jp->foreground = 0;
out1fmt("[%td] ", jp - jobtab + 1);
printjobcmd(jp);
} while (*argptr != NULL && *++argptr != NULL);
return 0;
}
static void
restartjob(struct job *jp)
{
struct procstat *ps;
int i;
if (jp->state == JOBDONE)
return;
setcurjob(jp);
INTOFF;
kill(-jp->ps[0].pid, SIGCONT);
for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
if (WIFSTOPPED(ps->status)) {
ps->status = -1;
jp->state = 0;
}
}
INTON;
}
#endif
int
jobscmd(int argc __unused, char *argv[] __unused)
{
char *id;
int ch, mode;
mode = SHOWJOBS_DEFAULT;
while ((ch = nextopt("lps")) != '\0') {
switch (ch) {
case 'l':
mode = SHOWJOBS_VERBOSE;
break;
case 'p':
mode = SHOWJOBS_PGIDS;
break;
case 's':
mode = SHOWJOBS_PIDS;
break;
}
}
if (*argptr == NULL)
showjobs(0, mode);
else
while ((id = *argptr++) != NULL)
showjob(getjob(id), mode);
return (0);
}
static int getjobstatus(const struct job *jp)
{
int i, status;
if (!jp->pipefail)
return (jp->ps[jp->nprocs - 1].status);
for (i = jp->nprocs - 1; i >= 0; i--) {
status = jp->ps[i].status;
if (status != 0)
return (status);
}
return (0);
}
static void
printjobcmd(struct job *jp)
{
struct procstat *ps;
int i;
for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
out1str(ps->cmd);
if (i > 0)
out1str(" | ");
}
out1c('\n');
}
static void
showjob(struct job *jp, int mode)
{
char s[64];
char statebuf[16];
const char *statestr, *coredump;
struct procstat *ps;
struct job *j;
int col, curr, i, jobno, prev, procno, status;
char c;
procno = (mode == SHOWJOBS_PGIDS) ? 1 : jp->nprocs;
jobno = jp - jobtab + 1;
curr = prev = 0;
#if JOBS
if ((j = getcurjob(NULL)) != NULL) {
curr = j - jobtab + 1;
if ((j = getcurjob(j)) != NULL)
prev = j - jobtab + 1;
}
#endif
coredump = "";
status = getjobstatus(jp);
if (jp->state == 0) {
statestr = "Running";
#if JOBS
} else if (jp->state == JOBSTOPPED) {
ps = jp->ps + jp->nprocs - 1;
while (!WIFSTOPPED(ps->status) && ps > jp->ps)
ps--;
if (WIFSTOPPED(ps->status))
i = WSTOPSIG(ps->status);
else
i = -1;
statestr = strsignal(i);
if (statestr == NULL)
statestr = "Suspended";
#endif
} else if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == 0)
statestr = "Done";
else {
fmtstr(statebuf, sizeof(statebuf), "Done(%d)",
WEXITSTATUS(status));
statestr = statebuf;
}
} else {
i = WTERMSIG(status);
statestr = strsignal(i);
if (statestr == NULL)
statestr = "Unknown signal";
if (WCOREDUMP(status))
coredump = " (core dumped)";
}
for (ps = jp->ps ; procno > 0 ; ps++, procno--) { /* for each process */
if (mode == SHOWJOBS_PIDS || mode == SHOWJOBS_PGIDS) {
out1fmt("%d\n", (int)ps->pid);
continue;
}
if (mode != SHOWJOBS_VERBOSE && ps != jp->ps)
continue;
if (jobno == curr && ps == jp->ps)
c = '+';
else if (jobno == prev && ps == jp->ps)
c = '-';
else
c = ' ';
if (ps == jp->ps)
fmtstr(s, 64, "[%d] %c ", jobno, c);
else
fmtstr(s, 64, " %c ", c);
out1str(s);
col = strlen(s);
if (mode == SHOWJOBS_VERBOSE) {
fmtstr(s, 64, "%d ", (int)ps->pid);
out1str(s);
col += strlen(s);
}
if (ps == jp->ps) {
out1str(statestr);
out1str(coredump);
col += strlen(statestr) + strlen(coredump);
}
do {
out1c(' ');
col++;
} while (col < 30);
if (mode == SHOWJOBS_VERBOSE) {
out1str(ps->cmd);
out1c('\n');
} else
printjobcmd(jp);
}
}
/*
* 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(int change, int mode)
{
int jobno;
struct job *jp;
TRACE(("showjobs(%d) called\n", change));
checkzombies();
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;
showjob(jp, mode);
if (mode == SHOWJOBS_DEFAULT || mode == SHOWJOBS_VERBOSE) {
jp->changed = 0;
/* Hack: discard jobs for which $! has not been
* referenced in interactive mode when they terminate.
*/
if (jp->state == JOBDONE && !jp->remembered &&
(iflag || jp != bgjob)) {
freejob(jp);
}
}
}
}
/*
* Mark a job structure as unused.
*/
static void
freejob(struct job *jp)
{
struct procstat *ps;
int i;
INTOFF;
if (bgjob == jp)
bgjob = NULL;
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
deljob(jp);
#endif
INTON;
}
int
waitcmd(int argc __unused, char **argv __unused)
{
struct job *job;
int retval;
nextopt("");
if (*argptr == NULL)
return (waitcmdloop(NULL));
do {
job = getjob_nonotfound(*argptr);
if (job == NULL)
retval = 127;
else
retval = waitcmdloop(job);
argptr++;
} while (*argptr != NULL);
return (retval);
}
static int
waitcmdloop(struct job *job)
{
int status, retval, sig;
struct job *jp;
/*
* Loop until a process is terminated or stopped, or a SIGINT is
* received.
*/
do {
if (job != NULL) {
if (job->state == JOBDONE) {
status = getjobstatus(job);
if (WIFEXITED(status))
retval = WEXITSTATUS(status);
else
retval = WTERMSIG(status) + 128;
if (! iflag || ! job->changed)
freejob(job);
else {
job->remembered = 0;
if (job == bgjob)
bgjob = NULL;
}
return retval;
}
} else {
for (jp = jobtab ; jp < jobtab + njobs; jp++)
if (jp->used && jp->state == JOBDONE) {
if (! iflag || ! jp->changed)
freejob(jp);
else {
jp->remembered = 0;
if (jp == bgjob)
bgjob = NULL;
}
}
for (jp = jobtab ; ; jp++) {
if (jp >= jobtab + njobs) { /* no running procs */
return 0;
}
if (jp->used && jp->state == 0)
break;
}
}
} while (dowait(DOWAIT_BLOCK | DOWAIT_SIG, (struct job *)NULL) != -1);
sig = pendingsig_waitcmd;
pendingsig_waitcmd = 0;
return sig + 128;
}
int
jobidcmd(int argc __unused, char **argv __unused)
{
struct job *jp;
int i;
nextopt("");
jp = getjob(*argptr);
for (i = 0 ; i < jp->nprocs ; ) {
out1fmt("%d", (int)jp->ps[i].pid);
out1c(++i < jp->nprocs? ' ' : '\n');
}
return 0;
}
/*
* Convert a job name to a job structure.
*/
static struct job *
getjob_nonotfound(const char *name)
{
int jobno;
struct job *found, *jp;
size_t namelen;
pid_t pid;
int i;
if (name == NULL) {
#if JOBS
name = "%+";
#else
error("No current job");
#endif
}
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[1] == '+') &&
name[2] == '\0') {
if ((jp = getcurjob(NULL)) == NULL)
error("No current job");
return (jp);
} else if (name[1] == '-' && name[2] == '\0') {
if ((jp = getcurjob(NULL)) == NULL ||
(jp = getcurjob(jp)) == NULL)
error("No previous job");
return (jp);
#endif
} else if (name[1] == '?') {
found = NULL;
for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
if (jp->used && jp->nprocs > 0
&& strstr(jp->ps[0].cmd, name + 2) != NULL) {
if (found)
error("%s: ambiguous", name);
found = jp;
}
}
if (found != NULL)
return (found);
} else {
namelen = strlen(name);
found = NULL;
for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
if (jp->used && jp->nprocs > 0
&& strncmp(jp->ps[0].cmd, name + 1,
namelen - 1) == 0) {
if (found)
error("%s: ambiguous", name);
found = jp;
}
}
if (found)
return found;
}
} else if (is_number(name)) {
pid = (pid_t)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;
}
}
return NULL;
}
static struct job *
getjob(const char *name)
{
struct job *jp;
jp = getjob_nonotfound(name);
if (jp == NULL)
error("No such job: %s", name);
return (jp);
}
int
killjob(const char *name, int sig)
{
struct job *jp;
int i, ret;
jp = getjob(name);
if (jp->state == JOBDONE)
return 0;
if (jp->jobctl)
return kill(-jp->ps[0].pid, sig);
ret = -1;
errno = ESRCH;
for (i = 0; i < jp->nprocs; i++)
if (jp->ps[i].status == -1 || WIFSTOPPED(jp->ps[i].status)) {
if (kill(jp->ps[i].pid, sig) == 0)
ret = 0;
} else
ret = 0;
return ret;
}
/*
* Return a new job structure,
*/
struct job *
makejob(union node *node __unused, 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]);
#if JOBS
jobmru = NULL;
#endif
} else {
jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
memcpy(jp, jobtab, njobs * sizeof jp[0]);
#if JOBS
/* Relocate `next' pointers and list head */
if (jobmru != NULL)
jobmru = &jp[jobmru - jobtab];
for (i = 0; i < njobs; i++)
if (jp[i].next != NULL)
jp[i].next = &jp[jp[i].next -
jobtab];
#endif
if (bgjob != NULL)
bgjob = &jp[bgjob - jobtab];
/* 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;
jp->foreground = 0;
jp->remembered = 0;
jp->pipefail = pipefailflag;
#if JOBS
jp->jobctl = jobctl;
jp->next = NULL;
#endif
if (nprocs > 1) {
jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
} else {
jp->ps = &jp->ps0;
}
INTON;
TRACE(("makejob(%p, %d) returns %%%td\n", (void *)node, nprocs,
jp - jobtab + 1));
return jp;
}
#if JOBS
static void
setcurjob(struct job *cj)
{
struct job *jp, *prev;
for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
if (jp == cj) {
if (prev != NULL)
prev->next = jp->next;
else
jobmru = jp->next;
jp->next = jobmru;
jobmru = cj;
return;
}
}
cj->next = jobmru;
jobmru = cj;
}
static void
deljob(struct job *j)
{
struct job *jp, *prev;
for (prev = NULL, jp = jobmru; jp != NULL; prev = jp, jp = jp->next) {
if (jp == j) {
if (prev != NULL)
prev->next = jp->next;
else
jobmru = jp->next;
return;
}
}
}
/*
* Return the most recently used job that isn't `nj', and preferably one
* that is stopped.
*/
static struct job *
getcurjob(struct job *nj)
{
struct job *jp;
/* Try to find a stopped one.. */
for (jp = jobmru; jp != NULL; jp = jp->next)
if (jp->used && jp != nj && jp->state == JOBSTOPPED)
return (jp);
/* Otherwise the most recently used job that isn't `nj' */
for (jp = jobmru; jp != NULL; jp = jp->next)
if (jp->used && jp != nj)
return (jp);
return (NULL);
}
#endif
/*
* 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).
*/
pid_t
forkshell(struct job *jp, union node *n, int mode)
{
pid_t pid;
pid_t pgrp;
TRACE(("forkshell(%%%td, %p, %d) called\n", jp - jobtab, (void *)n,
mode));
INTOFF;
if (mode == FORK_BG && (jp == NULL || jp->nprocs == 0))
checkzombies();
flushall();
pid = fork();
if (pid == -1) {
TRACE(("Fork failed, errno=%d\n", errno));
INTON;
error("Cannot fork: %s", strerror(errno));
}
if (pid == 0) {
struct job *p;
int wasroot;
int i;
TRACE(("Child shell %d\n", (int)getpid()));
wasroot = rootshell;
rootshell = 0;
handler = &main_handler;
closescript();
INTON;
forcelocal = 0;
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 &&
ttyfd >= 0) {
/*** this causes superfluous TIOCSPGRPS ***/
if (tcsetpgrp(ttyfd, pgrp) < 0)
error("tcsetpgrp failed, errno=%d", errno);
}
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(_PATH_DEVNULL, O_RDONLY) != 0)
error("cannot open %s: %s",
_PATH_DEVNULL, strerror(errno));
}
}
#else
if (mode == FORK_BG) {
ignoresig(SIGINT);
ignoresig(SIGQUIT);
if ((jp == NULL || jp->nprocs == 0) &&
! fd0_redirected_p ()) {
close(0);
if (open(_PATH_DEVNULL, O_RDONLY) != 0)
error("cannot open %s: %s",
_PATH_DEVNULL, strerror(errno));
}
}
#endif
INTOFF;
for (i = njobs, p = jobtab ; --i >= 0 ; p++)
if (p->used)
freejob(p);
INTON;
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) {
if (bgjob != NULL && bgjob->state == JOBDONE &&
!bgjob->remembered && !iflag)
freejob(bgjob);
backgndpid = pid; /* set $! */
bgjob = jp;
}
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);
jp->foreground = mode == FORK_FG;
#if JOBS
setcurjob(jp);
#endif
}
INTON;
TRACE(("In parent shell: child = %d\n", (int)pid));
return pid;
}
pid_t
vforkexecshell(struct job *jp, char **argv, char **envp, const char *path, int idx, int pip[2])
{
pid_t pid;
struct jmploc jmploc;
struct jmploc *savehandler;
int inton;
TRACE(("vforkexecshell(%%%td, %s, %p) called\n", jp - jobtab, argv[0],
(void *)pip));
inton = is_int_on();
INTOFF;
flushall();
savehandler = handler;
pid = vfork();
if (pid == -1) {
TRACE(("Vfork failed, errno=%d\n", errno));
INTON;
error("Cannot fork: %s", strerror(errno));
}
if (pid == 0) {
TRACE(("Child shell %d\n", (int)getpid()));
if (setjmp(jmploc.loc))
_exit(exitstatus);
if (pip != NULL) {
close(pip[0]);
if (pip[1] != 1) {
dup2(pip[1], 1);
close(pip[1]);
}
}
handler = &jmploc;
shellexec(argv, envp, path, idx);
}
handler = savehandler;
if (jp) {
struct procstat *ps = &jp->ps[jp->nprocs++];
ps->pid = pid;
ps->status = -1;
ps->cmd = nullstr;
jp->foreground = 1;
#if JOBS
setcurjob(jp);
#endif
}
SETINTON(inton);
TRACE(("In parent shell: child = %d\n", (int)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
* foreground 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(struct job *jp, int *signaled)
{
#if JOBS
int propagate_int = jp->jobctl && jp->foreground;
#endif
int status;
int st;
INTOFF;
TRACE(("waitforjob(%%%td) called\n", jp - jobtab + 1));
while (jp->state == 0)
if (dowait(DOWAIT_BLOCK | (Tflag ? DOWAIT_SIG |
DOWAIT_SIG_TRAP : 0), jp) == -1)
dotrap();
#if JOBS
if (jp->jobctl) {
if (ttyfd >= 0 && tcsetpgrp(ttyfd, rootpid) < 0)
error("tcsetpgrp failed, errno=%d\n", errno);
}
if (jp->state == JOBSTOPPED)
setcurjob(jp);
#endif
status = getjobstatus(jp);
if (signaled != NULL)
*signaled = WIFSIGNALED(status);
/* convert to 8 bits */
if (WIFEXITED(status))
st = WEXITSTATUS(status);
#if JOBS
else if (WIFSTOPPED(status))
st = WSTOPSIG(status) + 128;
#endif
else
st = WTERMSIG(status) + 128;
if (! JOBS || jp->state == JOBDONE)
freejob(jp);
if (int_pending()) {
if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGINT)
CLEAR_PENDING_INT;
}
#if JOBS
else if (rootshell && propagate_int &&
WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
kill(getpid(), SIGINT);
#endif
INTON;
return st;
}
static void
dummy_handler(int sig __unused)
{
}
/*
* Wait for a process to terminate.
*/
static pid_t
dowait(int mode, struct job *job)
{
struct sigaction sa, osa;
sigset_t mask, omask;
pid_t pid;
int status;
struct procstat *sp;
struct job *jp;
struct job *thisjob;
const char *sigstr;
int done;
int stopped;
int sig;
int coredump;
int wflags;
int restore_sigchld;
TRACE(("dowait(%d, %p) called\n", mode, job));
restore_sigchld = 0;
if ((mode & DOWAIT_SIG) != 0) {
sigfillset(&mask);
sigprocmask(SIG_BLOCK, &mask, &omask);
INTOFF;
if (!issigchldtrapped()) {
restore_sigchld = 1;
sa.sa_handler = dummy_handler;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sigaction(SIGCHLD, &sa, &osa);
}
}
do {
#if JOBS
if (iflag)
wflags = WUNTRACED | WCONTINUED;
else
#endif
wflags = 0;
if ((mode & (DOWAIT_BLOCK | DOWAIT_SIG)) != DOWAIT_BLOCK)
wflags |= WNOHANG;
pid = wait3(&status, wflags, (struct rusage *)NULL);
TRACE(("wait returns %d, status=%d\n", (int)pid, status));
if (pid == 0 && (mode & DOWAIT_SIG) != 0) {
pid = -1;
if (((mode & DOWAIT_SIG_TRAP) != 0 ?
pendingsig : pendingsig_waitcmd) != 0) {
errno = EINTR;
break;
}
sigsuspend(&omask);
if (int_pending())
break;
}
} while (pid == -1 && errno == EINTR);
if (pid == -1 && errno == ECHILD && job != NULL)
job->state = JOBDONE;
if ((mode & DOWAIT_SIG) != 0) {
if (restore_sigchld)
sigaction(SIGCHLD, &osa, NULL);
sigprocmask(SIG_SETMASK, &omask, NULL);
INTON;
}
if (pid <= 0)
return pid;
INTOFF;
thisjob = NULL;
for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
if (jp->used && jp->nprocs > 0) {
done = 1;
stopped = 1;
for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
if (sp->pid == -1)
continue;
if (sp->pid == pid && (sp->status == -1 ||
WIFSTOPPED(sp->status))) {
TRACE(("Changing status of proc %d from 0x%x to 0x%x\n",
(int)pid, sp->status,
status));
if (WIFCONTINUED(status)) {
sp->status = -1;
jp->state = 0;
} else
sp->status = status;
thisjob = jp;
}
if (sp->status == -1)
stopped = 0;
else if (WIFSTOPPED(sp->status))
done = 0;
}
if (stopped) { /* stopped or done */
int state = done? JOBDONE : JOBSTOPPED;
if (jp->state != state) {
TRACE(("Job %td: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
jp->state = state;
if (jp != job) {
if (done && !jp->remembered &&
!iflag && jp != bgjob)
freejob(jp);
#if JOBS
else if (done)
deljob(jp);
#endif
}
}
}
}
}
INTON;
if (!thisjob || thisjob->state == 0)
;
else if ((!rootshell || !iflag || thisjob == job) &&
thisjob->foreground && thisjob->state != JOBSTOPPED) {
sig = 0;
coredump = 0;
for (sp = thisjob->ps; sp < thisjob->ps + thisjob->nprocs; sp++)
if (WIFSIGNALED(sp->status)) {
sig = WTERMSIG(sp->status);
coredump = WCOREDUMP(sp->status);
}
if (sig > 0 && sig != SIGINT && sig != SIGPIPE) {
sigstr = strsignal(sig);
if (sigstr != NULL)
out2str(sigstr);
else
out2str("Unknown signal");
if (coredump)
out2str(" (core dumped)");
out2c('\n');
flushout(out2);
}
} else {
TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
thisjob->changed = 1;
}
return pid;
}
/*
* return 1 if there are stopped jobs, otherwise 0
*/
int job_warning = 0;
int
stoppedjobs(void)
{
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) {
out2fmt_flush("You have stopped jobs.\n");
job_warning = 2;
return (1);
}
}
return (0);
}
static void
checkzombies(void)
{
while (njobs > 0 && dowait(0, NULL) > 0)
;
}
int
backgndpidset(void)
{
return backgndpid != -1;
}
pid_t
backgndpidval(void)
{
if (bgjob != NULL && !forcelocal)
bgjob->remembered = 1;
return backgndpid;
}
/*
* Return a string identifying a command (to be printed by the
* jobs command.
*/
static char *cmdnextc;
static int cmdnleft;
#define MAXCMDTEXT 200
char *
commandtext(union node *n)
{
char *name;
cmdnextc = name = ckmalloc(MAXCMDTEXT);
cmdnleft = MAXCMDTEXT - 4;
cmdtxt(n);
*cmdnextc = '\0';
return name;
}
static void
cmdtxtdogroup(union node *n)
{
cmdputs("; do ");
cmdtxt(n);
cmdputs("; done");
}
static void
cmdtxtredir(union node *n, const char *op, int deffd)
{
char s[2];
if (n->nfile.fd != deffd) {
s[0] = n->nfile.fd + '0';
s[1] = '\0';
cmdputs(s);
}
cmdputs(op);
if (n->type == NTOFD || n->type == NFROMFD) {
if (n->ndup.dupfd >= 0)
s[0] = n->ndup.dupfd + '0';
else
s[0] = '-';
s[1] = '\0';
cmdputs(s);
} else {
cmdtxt(n->nfile.fname);
}
}
static void
cmdtxt(union node *n)
{
union node *np;
struct nodelist *lp;
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 ");
cmdtxt(n->nbinary.ch1);
cmdtxtdogroup(n->nbinary.ch2);
break;
case NUNTIL:
cmdputs("until ");
cmdtxt(n->nbinary.ch1);
cmdtxtdogroup(n->nbinary.ch2);
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 NNOT:
cmdputs("! ");
cmdtxt(n->nnot.com);
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:
cmdtxtredir(n, ">", 1);
break;
case NAPPEND:
cmdtxtredir(n, ">>", 1);
break;
case NTOFD:
cmdtxtredir(n, ">&", 1);
break;
case NCLOBBER:
cmdtxtredir(n, ">|", 1);
break;
case NFROM:
cmdtxtredir(n, "<", 0);
break;
case NFROMTO:
cmdtxtredir(n, "<>", 0);
break;
case NFROMFD:
cmdtxtredir(n, "<&", 0);
break;
case NHERE:
case NXHERE:
cmdputs("<<...");
break;
default:
cmdputs("???");
break;
}
}
static void
cmdputs(const char *s)
{
const char *p;
char *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++;
if ((subtype & VSTYPE) == VSLENGTH && --cmdnleft > 0)
*q++ = '#';
} else if (c == '=' && subtype != 0) {
*q = "}-+?=##%%\0X"[(subtype & VSTYPE) - VSNORMAL];
if (*q)
q++;
else
cmdnleft++;
if (((subtype & VSTYPE) == VSTRIMLEFTMAX ||
(subtype & VSTYPE) == VSTRIMRIGHTMAX) &&
--cmdnleft > 0)
*q = q[-1], q++;
subtype = 0;
} else if (c == CTLENDVAR) {
*q++ = '}';
} else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE) {
cmdnleft -= 5;
if (cmdnleft > 0) {
*q++ = '$';
*q++ = '(';
*q++ = '.';
*q++ = '.';
*q++ = '.';
*q++ = ')';
}
} else if (c == CTLARI) {
cmdnleft -= 2;
if (cmdnleft > 0) {
*q++ = '$';
*q++ = '(';
*q++ = '(';
}
p++;
} else if (c == CTLENDARI) {
if (--cmdnleft > 0) {
*q++ = ')';
*q++ = ')';
}
} else if (c == CTLQUOTEMARK || c == CTLQUOTEEND)
cmdnleft++; /* ignore */
else
*q++ = c;
if (--cmdnleft <= 0) {
*q++ = '.';
*q++ = '.';
*q++ = '.';
break;
}
}
cmdnextc = q;
}
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