jobs.c

android-w.song.android.widget

/* jobs.c - functions that make children, remember them, and handle their termination. */

/* This file works with both POSIX and BSD systems.  It implements job
   control. */

/* Copyright (C) 1989-2010 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Bash is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "config.h"

#include "bashtypes.h"
#include "trap.h"
#include <stdio.h>
#include <signal.h>
#include <errno.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include "posixtime.h"

#if defined (HAVE_SYS_RESOURCE_H) && defined (HAVE_WAIT3) && !defined (_POSIX_VERSION) && !defined (RLIMTYPE)
#  include <sys/resource.h>
#endif /* !_POSIX_VERSION && HAVE_SYS_RESOURCE_H && HAVE_WAIT3 && !RLIMTYPE */

#if defined (HAVE_SYS_FILE_H)
#  include <sys/file.h>
#endif

#include "filecntl.h"
#include <sys/ioctl.h>
#include <sys/param.h>

#if defined (BUFFERED_INPUT)
#  include "input.h"
#endif

/* Need to include this up here for *_TTY_DRIVER definitions. */
#include "shtty.h"

/* Define this if your output is getting swallowed.  It's a no-op on
   machines with the termio or termios tty drivers. */
/* #define DRAIN_OUTPUT */

/* For the TIOCGPGRP and TIOCSPGRP ioctl parameters on HP-UX */
#if defined (hpux) && !defined (TERMIOS_TTY_DRIVER)
#  include <bsdtty.h>
#endif /* hpux && !TERMIOS_TTY_DRIVER */

#include "bashansi.h"
#include "bashintl.h"
#include "shell.h"
#include "jobs.h"
#include "execute_cmd.h"
#include "flags.h"

#include "builtins/builtext.h"
#include "builtins/common.h"

#if !defined (errno)
extern int errno;
#endif /* !errno */

#if !defined (HAVE_KILLPG)
extern int killpg __P((pid_t, int));
#endif

#define DEFAULT_CHILD_MAX 32
#if !defined (DEBUG)
#define MAX_JOBS_IN_ARRAY 4096		/* production */
#else
#define MAX_JOBS_IN_ARRAY 128		/* testing */
#endif

/* Flag values for second argument to delete_job */
#define DEL_WARNSTOPPED		1	/* warn about deleting stopped jobs */
#define DEL_NOBGPID		2	/* don't add pgrp leader to bgpids */

/* Take care of system dependencies that must be handled when waiting for
   children.  The arguments to the WAITPID macro match those to the Posix.1
   waitpid() function. */

#if defined (ultrix) && defined (mips) && defined (_POSIX_VERSION)
#  define WAITPID(pid, statusp, options) \
	wait3 ((union wait *)statusp, options, (struct rusage *)0)
#else
#  if defined (_POSIX_VERSION) || defined (HAVE_WAITPID)
#    define WAITPID(pid, statusp, options) \
	waitpid ((pid_t)pid, statusp, options)
#  else
#    if defined (HAVE_WAIT3)
#      define WAITPID(pid, statusp, options) \
	wait3 (statusp, options, (struct rusage *)0)
#    else
#      define WAITPID(pid, statusp, options) \
	wait3 (statusp, options, (int *)0)
#    endif /* HAVE_WAIT3 */
#  endif /* !_POSIX_VERSION && !HAVE_WAITPID*/
#endif /* !(Ultrix && mips && _POSIX_VERSION) */

/* getpgrp () varies between systems.  Even systems that claim to be
   Posix.1 compatible lie sometimes (Ultrix, SunOS4, apollo). */
#if defined (GETPGRP_VOID)
#  define getpgid(p) getpgrp ()
#else
#  define getpgid(p) getpgrp (p)
#endif /* !GETPGRP_VOID */

/* If the system needs it, REINSTALL_SIGCHLD_HANDLER will reinstall the
   handler for SIGCHLD. */
#if defined (MUST_REINSTALL_SIGHANDLERS)
#  define REINSTALL_SIGCHLD_HANDLER signal (SIGCHLD, sigchld_handler)
#else
#  define REINSTALL_SIGCHLD_HANDLER
#endif /* !MUST_REINSTALL_SIGHANDLERS */

/* Some systems let waitpid(2) tell callers about stopped children. */
#if !defined (WCONTINUED) || defined (WCONTINUED_BROKEN)
#  undef WCONTINUED
#  define WCONTINUED 0
#endif
#if !defined (WIFCONTINUED)
#  define WIFCONTINUED(s)	(0)
#endif

/* The number of additional slots to allocate when we run out. */
#define JOB_SLOTS 8

typedef int sh_job_map_func_t __P((JOB *, int, int, int));

/* Variables used here but defined in other files. */
extern int subshell_environment, line_number;
extern int posixly_correct, shell_level;
extern int last_command_exit_value, last_command_exit_signal;
extern int loop_level, breaking;
extern int executing_list;
extern int sourcelevel;
extern int running_trap;
extern sh_builtin_func_t *this_shell_builtin;
extern char *shell_name, *this_command_name;
extern sigset_t top_level_mask;
extern procenv_t wait_intr_buf;
extern int wait_signal_received;
extern WORD_LIST *subst_assign_varlist;

static struct jobstats zerojs = { -1L, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, NO_JOB, NO_JOB, 0, 0 };
struct jobstats js = { -1L, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, NO_JOB, NO_JOB, 0, 0 };

struct bgpids bgpids = { 0, 0, 0 };

/* The array of known jobs. */
JOB **jobs = (JOB **)NULL;

#if 0
/* The number of slots currently allocated to JOBS. */
int job_slots = 0;
#endif

/* The controlling tty for this shell. */
int shell_tty = -1;

/* The shell's process group. */
pid_t shell_pgrp = NO_PID;

/* The terminal's process group. */
pid_t terminal_pgrp = NO_PID;

/* The process group of the shell's parent. */
pid_t original_pgrp = NO_PID;

/* The process group of the pipeline currently being made. */
pid_t pipeline_pgrp = (pid_t)0;

#if defined (PGRP_PIPE)
/* Pipes which each shell uses to communicate with the process group leader
   until all of the processes in a pipeline have been started.  Then the
   process leader is allowed to continue. */
int pgrp_pipe[2] = { -1, -1 };
#endif

#if 0
/* The job which is current; i.e. the one that `%+' stands for. */
int current_job = NO_JOB;

/* The previous job; i.e. the one that `%-' stands for. */
int previous_job = NO_JOB;
#endif

/* Last child made by the shell.  */
pid_t last_made_pid = NO_PID;

/* Pid of the last asynchronous child. */
pid_t last_asynchronous_pid = NO_PID;

/* The pipeline currently being built. */
PROCESS *the_pipeline = (PROCESS *)NULL;

/* If this is non-zero, do job control. */
int job_control = 1;

/* Call this when you start making children. */
int already_making_children = 0;

/* If this is non-zero, $LINES and $COLUMNS are reset after every process
   exits from get_tty_state(). */
int check_window_size;

/* Functions local to this file. */

static sighandler wait_sigint_handler __P((int));
static sighandler sigchld_handler __P((int));
static sighandler sigcont_sighandler __P((int));
static sighandler sigstop_sighandler __P((int));

static int waitchld __P((pid_t, int));

static PROCESS *find_pipeline __P((pid_t, int, int *));
static PROCESS *find_process __P((pid_t, int, int *));

static char *current_working_directory __P((void));
static char *job_working_directory __P((void));
static char *j_strsignal __P((int));
static char *printable_job_status __P((int, PROCESS *, int));

static PROCESS *find_last_proc __P((int, int));
static pid_t find_last_pid __P((int, int));

static int set_new_line_discipline __P((int));
static int map_over_jobs __P((sh_job_map_func_t *, int, int));
static int job_last_stopped __P((int));
static int job_last_running __P((int));
static int most_recent_job_in_state __P((int, JOB_STATE));
static int find_job __P((pid_t, int, PROCESS **));
static int print_job __P((JOB *, int, int, int));
static int process_exit_status __P((WAIT));
static int process_exit_signal __P((WAIT));
static int set_job_status_and_cleanup __P((int));

static WAIT job_signal_status __P((int));
static WAIT raw_job_exit_status __P((int));

static void notify_of_job_status __P((void));
static void reset_job_indices __P((void));
static void cleanup_dead_jobs __P((void));
static int processes_in_job __P((int));
static void realloc_jobs_list __P((void));
static int compact_jobs_list __P((int));
static int discard_pipeline __P((PROCESS *));
static void add_process __P((char *, pid_t));
static void print_pipeline __P((PROCESS *, int, int, FILE *));
static void pretty_print_job __P((int, int, FILE *));
static void set_current_job __P((int));
static void reset_current __P((void));
static void set_job_running __P((int));
static void setjstatus __P((int));
static int maybe_give_terminal_to __P((pid_t, pid_t, int));
static void mark_all_jobs_as_dead __P((void));
static void mark_dead_jobs_as_notified __P((int));
static void restore_sigint_handler __P((void));
#if defined (PGRP_PIPE)
static void pipe_read __P((int *));
#endif

static struct pidstat *bgp_alloc __P((pid_t, int));
static struct pidstat *bgp_add __P((pid_t, int));
static int bgp_delete __P((pid_t));
static void bgp_clear __P((void));
static int bgp_search __P((pid_t));
static void bgp_prune __P((void));

#if defined (ARRAY_VARS)
static int *pstatuses;		/* list of pipeline statuses */
static int statsize;
#endif

/* Used to synchronize between wait_for and other functions and the SIGCHLD
   signal handler. */
static int sigchld;
static int queue_sigchld;

#define QUEUE_SIGCHLD(os)	(os) = sigchld, queue_sigchld++

#define UNQUEUE_SIGCHLD(os) \
	do { \
	  queue_sigchld--; \
	  if (queue_sigchld == 0 && os != sigchld) \
	    waitchld (-1, 0); \
	} while (0)

static SigHandler *old_tstp, *old_ttou, *old_ttin;
static SigHandler *old_cont = (SigHandler *)SIG_DFL;

/* A place to temporarily save the current pipeline. */
static PROCESS *saved_pipeline;
static int saved_already_making_children;

/* Set this to non-zero whenever you don't want the jobs list to change at
   all: no jobs deleted and no status change notifications.  This is used,
   for example, when executing SIGCHLD traps, which may run arbitrary
   commands. */
static int jobs_list_frozen;

static char retcode_name_buffer[64];

/* flags to detect pid wraparound */
static pid_t first_pid = NO_PID;
static int pid_wrap = -1;

#if !defined (_POSIX_VERSION)

/* These are definitions to map POSIX 1003.1 functions onto existing BSD
   library functions and system calls. */
#define setpgid(pid, pgrp)	setpgrp (pid, pgrp)
#define tcsetpgrp(fd, pgrp)	ioctl ((fd), TIOCSPGRP, &(pgrp))

pid_t
tcgetpgrp (fd)
     int fd;
{
  pid_t pgrp;

  /* ioctl will handle setting errno correctly. */
  if (ioctl (fd, TIOCGPGRP, &pgrp) < 0)
    return (-1);
  return (pgrp);
}

#endif /* !_POSIX_VERSION */

/* Initialize the global job stats structure and other bookkeeping variables */
void
init_job_stats ()
{
  js = zerojs;
  first_pid = NO_PID;
  pid_wrap = -1;
}

/* Return the working directory for the current process.  Unlike
   job_working_directory, this does not call malloc (), nor do any
   of the functions it calls.  This is so that it can safely be called
   from a signal handler. */
static char *
current_working_directory ()
{
  char *dir;
  static char d[PATH_MAX];

  dir = get_string_value ("PWD");

  if (dir == 0 && the_current_working_directory && no_symbolic_links)
    dir = the_current_working_directory;

  if (dir == 0)
    {
      dir = getcwd (d, sizeof(d));
      if (dir)
	dir = d;
    }

  return (dir == 0) ? "<unknown>" : dir;
}

/* Return the working directory for the current process. */
static char *
job_working_directory ()
{
  char *dir;

  dir = get_string_value ("PWD");
  if (dir)
    return (savestring (dir));

  dir = get_working_directory ("job-working-directory");
  if (dir)
    return (dir);

  return (savestring ("<unknown>"));
}

void
making_children ()
{
  if (already_making_children)
    return;

  already_making_children = 1;
  start_pipeline ();
}

void
stop_making_children ()
{
  already_making_children = 0;
}

void
cleanup_the_pipeline ()
{
  PROCESS *disposer;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);
  disposer = the_pipeline;
  the_pipeline = (PROCESS *)NULL;
  UNBLOCK_CHILD (oset);

  if (disposer)
    discard_pipeline (disposer);
}

void
save_pipeline (clear)
     int clear;
{
  saved_pipeline = the_pipeline;
  if (clear)
    the_pipeline = (PROCESS *)NULL;
  saved_already_making_children = already_making_children;
}

void
restore_pipeline (discard)
     int discard;
{
  PROCESS *old_pipeline;

  old_pipeline = the_pipeline;
  the_pipeline = saved_pipeline;
  already_making_children = saved_already_making_children;
  if (discard && old_pipeline)
    discard_pipeline (old_pipeline);
}

/* Start building a pipeline.  */
void
start_pipeline ()
{
  if (the_pipeline)
    {
      cleanup_the_pipeline ();
      pipeline_pgrp = 0;
#if defined (PGRP_PIPE)
      sh_closepipe (pgrp_pipe);
#endif
    }

#if defined (PGRP_PIPE)
  if (job_control)
    {
      if (pipe (pgrp_pipe) == -1)
	sys_error (_("start_pipeline: pgrp pipe"));
    }
#endif
}

/* Stop building a pipeline.  Install the process list in the job array.
   This returns the index of the newly installed job.
   DEFERRED is a command structure to be executed upon satisfactory
   execution exit of this pipeline. */
int
stop_pipeline (async, deferred)
     int async;
     COMMAND *deferred;
{
  register int i, j;
  JOB *newjob;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

#if defined (PGRP_PIPE)
  /* The parent closes the process group synchronization pipe. */
  sh_closepipe (pgrp_pipe);
#endif

  cleanup_dead_jobs ();

  if (js.j_jobslots == 0)
    {
      js.j_jobslots = JOB_SLOTS;
      jobs = (JOB **)xmalloc (js.j_jobslots * sizeof (JOB *));

      /* Now blank out these new entries. */
      for (i = 0; i < js.j_jobslots; i++)
	jobs[i] = (JOB *)NULL;

      js.j_firstj = js.j_lastj = js.j_njobs = 0;
    }

  /* Scan from the last slot backward, looking for the next free one. */
  /* XXX - revisit this interactive assumption */
  /* XXX - this way for now */
  if (interactive)
    {