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jobs.c
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jobs.c
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/* 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) 1989-2022 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>
#if defined (HAVE_SYS_PARAM_H)
#include <sys/param.h>
#endif
#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 "parser.h"
#include "jobs.h"
#include "execute_cmd.h"
#include "flags.h"
#include "typemax.h"
#include "builtins/builtext.h"
#include "builtins/common.h"
#if defined (READLINE)
# include <readline/readline.h>
#endif
#if !defined (errno)
extern int errno;
#endif /* !errno */
#if !defined (HAVE_KILLPG)
extern int killpg PARAMS((pid_t, int));
#endif
#if !DEFAULT_CHILD_MAX
# define DEFAULT_CHILD_MAX 4096
#endif
#if !MAX_CHILD_MAX
# define MAX_CHILD_MAX 32768
#endif
#if !defined (DEBUG)
#define MAX_JOBS_IN_ARRAY 4096 /* production */
#else
#define MAX_JOBS_IN_ARRAY 128 /* testing */
#endif
/* XXX for now */
#define PIDSTAT_TABLE_SZ 4096
#define BGPIDS_TABLE_SZ 512
/* 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 PARAMS((JOB *, int, int, int));
/* Variables used here but defined in other files. */
extern WORD_LIST *subst_assign_varlist;
extern SigHandler **original_signals;
extern void set_original_signal PARAMS((int, SigHandler *));
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 };
ps_index_t pidstat_table[PIDSTAT_TABLE_SZ];
struct bgpids bgpids = { 0, 0, 0, 0 };
struct procchain procsubs = { 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
/* Last child made by the shell. */
volatile pid_t last_made_pid = NO_PID;
/* Pid of the last asynchronous child. */
volatile 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;
/* Are we running in background? (terminal_pgrp != shell_pgrp) */
int running_in_background = 0;
/* 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 = CHECKWINSIZE_DEFAULT;
PROCESS *last_procsub_child = (PROCESS *)NULL;
/* Functions local to this file. */
void debug_print_pgrps (void);
static sighandler wait_sigint_handler PARAMS((int));
static sighandler sigchld_handler PARAMS((int));
static sighandler sigcont_sighandler PARAMS((int));
static sighandler sigstop_sighandler PARAMS((int));
static int waitchld PARAMS((pid_t, int));
static PROCESS *find_pid_in_pipeline PARAMS((pid_t, PROCESS *, int));
static PROCESS *find_pipeline PARAMS((pid_t, int, int *));
static PROCESS *find_process PARAMS((pid_t, int, int *));
static char *current_working_directory PARAMS((void));
static char *job_working_directory PARAMS((void));
static char *j_strsignal PARAMS((int));
static char *printable_job_status PARAMS((int, PROCESS *, int));
static PROCESS *find_last_proc PARAMS((int, int));
static pid_t find_last_pid PARAMS((int, int));
static int set_new_line_discipline PARAMS((int));
static int map_over_jobs PARAMS((sh_job_map_func_t *, int, int));
static int job_last_stopped PARAMS((int));
static int job_last_running PARAMS((int));
static int most_recent_job_in_state PARAMS((int, JOB_STATE));
static int find_job PARAMS((pid_t, int, PROCESS **));
static int print_job PARAMS((JOB *, int, int, int));
static int process_exit_status PARAMS((WAIT));
static int process_exit_signal PARAMS((WAIT));
static int set_job_status_and_cleanup PARAMS((int));
static WAIT job_signal_status PARAMS((int));
static WAIT raw_job_exit_status PARAMS((int));
static void notify_of_job_status PARAMS((void));
static void reset_job_indices PARAMS((void));
static void cleanup_dead_jobs PARAMS((void));
static int processes_in_job PARAMS((int));
static void realloc_jobs_list PARAMS((void));
static int compact_jobs_list PARAMS((int));
static void add_process PARAMS((char *, pid_t));
static void print_pipeline PARAMS((PROCESS *, int, int, FILE *));
static void pretty_print_job PARAMS((int, int, FILE *));
static void set_current_job PARAMS((int));
static void reset_current PARAMS((void));
static void set_job_running PARAMS((int));
static void setjstatus PARAMS((int));
static int maybe_give_terminal_to PARAMS((pid_t, pid_t, int));
static void mark_all_jobs_as_dead PARAMS((void));
static void mark_dead_jobs_as_notified PARAMS((int));
static void restore_sigint_handler PARAMS((void));
#if defined (PGRP_PIPE)
static void pipe_read PARAMS((int *));
#endif
/* Hash table manipulation */
static ps_index_t *pshash_getbucket PARAMS((pid_t));
static void pshash_delindex PARAMS((ps_index_t));
/* Saved background process status management */
static struct pidstat *bgp_add PARAMS((pid_t, int));
static int bgp_delete PARAMS((pid_t));
static void bgp_clear PARAMS((void));
static int bgp_search PARAMS((pid_t));
static struct pipeline_saver *alloc_pipeline_saver PARAMS((void));
static ps_index_t bgp_getindex PARAMS((void));
static void bgp_resize PARAMS((void)); /* XXX */
#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++
/* We set queue_sigchld around the call to waitchld to protect data structures
from a SIGCHLD arriving while waitchld is executing. */
#define UNQUEUE_SIGCHLD(os) \
do { \
queue_sigchld--; \
if (queue_sigchld == 0 && os != sigchld) \
{ \
queue_sigchld = 1; \
waitchld (-1, 0); \
queue_sigchld = 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 struct pipeline_saver *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];
#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;
}
/* 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);
}
/* Not used right now */
void
discard_last_procsub_child ()
{
PROCESS *disposer;
sigset_t set, oset;
BLOCK_CHILD (set, oset);
disposer = last_procsub_child;
last_procsub_child = (PROCESS *)NULL;
UNBLOCK_CHILD (oset);
if (disposer)
discard_pipeline (disposer);
}
static struct pipeline_saver *
alloc_pipeline_saver ()
{
struct pipeline_saver *ret;
ret = (struct pipeline_saver *)xmalloc (sizeof (struct pipeline_saver));
ret->pipeline = 0;
ret->next = 0;
return ret;
}
void
save_pipeline (clear)
int clear;
{
sigset_t set, oset;
struct pipeline_saver *saver;
BLOCK_CHILD (set, oset);
saver = alloc_pipeline_saver ();
saver->pipeline = the_pipeline;
saver->next = saved_pipeline;
saved_pipeline = saver;
if (clear)
the_pipeline = (PROCESS *)NULL;
saved_already_making_children = already_making_children;
UNBLOCK_CHILD (oset);
}
PROCESS *
restore_pipeline (discard)
int discard;
{
PROCESS *old_pipeline;
sigset_t set, oset;
struct pipeline_saver *saver;
BLOCK_CHILD (set, oset);
old_pipeline = the_pipeline;
the_pipeline = saved_pipeline->pipeline;
saver = saved_pipeline;
saved_pipeline = saved_pipeline->next;
free (saver);
already_making_children = saved_already_making_children;
UNBLOCK_CHILD (oset);
if (discard && old_pipeline)
{
discard_pipeline (old_pipeline);
return ((PROCESS *)NULL);
}
return old_pipeline;
}
/* Start building a pipeline. */
void
start_pipeline ()
{
if (the_pipeline)
{
cleanup_the_pipeline ();
/* If job_control == 0, pipeline_pgrp will always be equal to shell_pgrp;
if job_control != 0, pipeline_pgrp == shell_pgrp for command and
process substitution, in which case we want it to be the same as
shell_pgrp for the lifetime of this shell instance. */
if (pipeline_pgrp != shell_pgrp)
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)
{
for (i = js.j_jobslots; i; i--)
if (jobs[i - 1])
break;
}
else
{
#if 0
/* This wraps around, but makes it inconvenient to extend the array */
for (i = js.j_lastj+1; i != js.j_lastj; i++)
{
if (i >= js.j_jobslots)
i = 0;
if (jobs[i] == 0)
break;
}
if (i == js.j_lastj)
i = js.j_jobslots;
#else
/* This doesn't wrap around yet. */
for (i = js.j_lastj ? js.j_lastj + 1 : js.j_lastj; i < js.j_jobslots; i++)
if (jobs[i] == 0)
break;
#endif
}
/* Do we need more room? */
/* First try compaction */
if ((interactive_shell == 0 || subshell_environment) && i == js.j_jobslots && js.j_jobslots >= MAX_JOBS_IN_ARRAY)
i = compact_jobs_list (0);
/* If we can't compact, reallocate */
if (i == js.j_jobslots)
{
js.j_jobslots += JOB_SLOTS;
jobs = (JOB **)xrealloc (jobs, (js.j_jobslots * sizeof (JOB *)));
for (j = i; j < js.j_jobslots; j++)
jobs[j] = (JOB *)NULL;
}
/* Add the current pipeline to the job list. */
if (the_pipeline)
{
register PROCESS *p;
int any_running, any_stopped, n;
newjob = (JOB *)xmalloc (sizeof (JOB));
for (n = 1, p = the_pipeline; p->next != the_pipeline; n++, p = p->next)
;
p->next = (PROCESS *)NULL;
newjob->pipe = REVERSE_LIST (the_pipeline, PROCESS *);
for (p = newjob->pipe; p->next; p = p->next)
;
p->next = newjob->pipe;
the_pipeline = (PROCESS *)NULL;
newjob->pgrp = pipeline_pgrp;
/* Invariant: if the shell is executing a command substitution,
pipeline_pgrp == shell_pgrp. Other parts of the shell assume this. */
if (pipeline_pgrp != shell_pgrp)
pipeline_pgrp = 0;
newjob->flags = 0;
if (pipefail_opt)
newjob->flags |= J_PIPEFAIL;
/* Flag to see if in another pgrp. */
if (job_control)
newjob->flags |= J_JOBCONTROL;
/* Set the state of this pipeline. */
p = newjob->pipe;
any_running = any_stopped = 0;
do
{
any_running |= PRUNNING (p);
any_stopped |= PSTOPPED (p);
p = p->next;
}
while (p != newjob->pipe);
newjob->state = any_running ? JRUNNING : (any_stopped ? JSTOPPED : JDEAD);
newjob->wd = job_working_directory ();
newjob->deferred = deferred;
newjob->j_cleanup = (sh_vptrfunc_t *)NULL;
newjob->cleanarg = (PTR_T) NULL;
jobs[i] = newjob;
if (newjob->state == JDEAD && (newjob->flags & J_FOREGROUND))
setjstatus (i);
if (newjob->state == JDEAD)
{
js.c_reaped += n; /* wouldn't have been done since this was not part of a job */
js.j_ndead++;
}
js.c_injobs += n;
js.j_lastj = i;
js.j_njobs++;
}
else
newjob = (JOB *)NULL;
if (newjob)
js.j_lastmade = newjob;
if (async)
{
if (newjob)
{
newjob->flags &= ~J_FOREGROUND;
newjob->flags |= J_ASYNC;
js.j_lastasync = newjob;
}
reset_current ();
}
else
{
if (newjob)
{
newjob->flags |= J_FOREGROUND;
/*
* !!!!! NOTE !!!!! ([email protected])
*
* The currently-accepted job control wisdom says to set the
* terminal's process group n+1 times in an n-step pipeline:
* once in the parent and once in each child. This is where
* the parent gives it away.
*
* Don't give the terminal away if this shell is an asynchronous
* subshell or if we're a (presumably non-interactive) shell running
* in the background.
*
*/
if (job_control && newjob->pgrp && (subshell_environment&SUBSHELL_ASYNC) == 0 && running_in_background == 0)
maybe_give_terminal_to (shell_pgrp, newjob->pgrp, 0);
}
}
stop_making_children ();
UNBLOCK_CHILD (oset);
return (newjob ? i : js.j_current);
}
/* Functions to manage the list of exited background pids whose status has
been saved.
pidstat_table:
The current implementation is a hash table using a single (separate) arena
for storage that can be allocated and freed as a unit. The size of the hash
table is a multiple of PIDSTAT_TABLE_SZ (4096) and multiple PIDs that hash
to the same value are chained through the bucket_next and bucket_prev
pointers (basically coalesced hashing for collision resolution).
bgpids.storage:
All pid/status storage is done using the circular buffer bgpids.storage.
This must contain at least js.c_childmax entries. The circular buffer is
used to supply the ordered list Posix requires ("the last CHILD_MAX
processes"). To avoid searching the entire storage table for a given PID,
the hash table (pidstat_table) holds pointers into the storage arena and
uses a doubly-linked list of cells (bucket_next/bucket_prev, also pointers
into the arena) to implement collision resolution. */
/* The number of elements in bgpids.storage always has to be > js.c_childmax for
the circular buffer to work right. */
static void
bgp_resize ()
{
ps_index_t nsize, nsize_cur, nsize_max;
ps_index_t psi;
if (bgpids.nalloc == 0)
{
/* invalidate hash table when bgpids table is reallocated */
for (psi = 0; psi < PIDSTAT_TABLE_SZ; psi++)
pidstat_table[psi] = NO_PIDSTAT;
nsize = BGPIDS_TABLE_SZ; /* should be power of 2 */
bgpids.head = 0;
}
else
nsize = bgpids.nalloc;
nsize_max = TYPE_MAXIMUM (ps_index_t);
nsize_cur = (ps_index_t)js.c_childmax;
if (nsize_cur < 0) /* overflow */
nsize_cur = MAX_CHILD_MAX;
while (nsize > 0 && nsize < nsize_cur) /* > 0 should catch overflow */
nsize <<= 1;
if (nsize > nsize_max || nsize <= 0) /* overflow? */
nsize = nsize_max;
if (nsize > MAX_CHILD_MAX)
nsize = nsize_max = MAX_CHILD_MAX; /* hard cap */
if (bgpids.nalloc < nsize_cur && bgpids.nalloc < nsize_max)
{
bgpids.storage = (struct pidstat *)xrealloc (bgpids.storage, nsize * sizeof (struct pidstat));
for (psi = bgpids.nalloc; psi < nsize; psi++)
bgpids.storage[psi].pid = NO_PID;
bgpids.nalloc = nsize;
}
else if (bgpids.head >= bgpids.nalloc) /* wrap around */
bgpids.head = 0;
}
static ps_index_t
bgp_getindex ()
{
if (bgpids.nalloc < (ps_index_t)js.c_childmax || bgpids.head >= bgpids.nalloc)
bgp_resize ();
pshash_delindex (bgpids.head); /* XXX - clear before reusing */
return bgpids.head++;
}
static ps_index_t *
pshash_getbucket (pid)
pid_t pid;
{
unsigned long hash; /* XXX - u_bits32_t */
hash = pid * 0x9e370001UL;
return (&pidstat_table[hash % PIDSTAT_TABLE_SZ]);
}
static struct pidstat *
bgp_add (pid, status)
pid_t pid;
int status;
{
ps_index_t *bucket, psi;
struct pidstat *ps;
/* bucket == existing chain of pids hashing to same value
psi = where were going to put this pid/status */
bucket = pshash_getbucket (pid); /* index into pidstat_table */
psi = bgp_getindex (); /* bgpids.head, index into storage */
/* XXX - what if psi == *bucket? */
if (psi == *bucket)
{
internal_debug ("hashed pid %d (pid %d) collides with bgpids.head, skipping", psi, pid);
bgpids.storage[psi].pid = NO_PID; /* make sure */
psi = bgp_getindex (); /* skip to next one */
}
ps = &bgpids.storage[psi];
ps->pid = pid;
ps->status = status;
ps->bucket_next = *bucket;
ps->bucket_prev = NO_PIDSTAT;
bgpids.npid++;
#if 0
if (bgpids.npid > js.c_childmax)
bgp_prune ();
#endif
if (ps->bucket_next != NO_PIDSTAT)
bgpids.storage[ps->bucket_next].bucket_prev = psi;
*bucket = psi; /* set chain head in hash table */
return ps;
}
static void
pshash_delindex (psi)
ps_index_t psi;
{
struct pidstat *ps;
ps_index_t *bucket;
ps = &bgpids.storage[psi];
if (ps->pid == NO_PID)
return;
if (ps->bucket_next != NO_PIDSTAT)
bgpids.storage[ps->bucket_next].bucket_prev = ps->bucket_prev;
if (ps->bucket_prev != NO_PIDSTAT)
bgpids.storage[ps->bucket_prev].bucket_next = ps->bucket_next;
else
{
bucket = pshash_getbucket (ps->pid);
*bucket = ps->bucket_next; /* deleting chain head in hash table */
}
/* clear out this cell, in case it gets reused. */
ps->pid = NO_PID;
ps->bucket_next = ps->bucket_prev = NO_PIDSTAT;
}
static int
bgp_delete (pid)
pid_t pid;
{
ps_index_t psi, orig_psi;
if (bgpids.storage == 0 || bgpids.nalloc == 0 || bgpids.npid == 0)
return 0;
/* Search chain using hash to find bucket in pidstat_table */
for (orig_psi = psi = *(pshash_getbucket (pid)); psi != NO_PIDSTAT; psi = bgpids.storage[psi].bucket_next)
{
if (bgpids.storage[psi].pid == pid)
break;
if (orig_psi == bgpids.storage[psi].bucket_next) /* catch reported bug */
{
internal_warning (_("bgp_delete: LOOP: psi (%d) == storage[psi].bucket_next"), psi);
return 0;
}
}
if (psi == NO_PIDSTAT)
return 0; /* not found */
#if 0
itrace("bgp_delete: deleting %d", pid);
#endif
pshash_delindex (psi); /* hash table management */
bgpids.npid--;
return 1;
}
/* Clear out the list of saved statuses */
static void
bgp_clear ()
{
if (bgpids.storage == 0 || bgpids.nalloc == 0)
return;
free (bgpids.storage);
bgpids.storage = 0;
bgpids.nalloc = 0;
bgpids.head = 0;
bgpids.npid = 0;
}
/* Search for PID in the list of saved background pids; return its status if
found. If not found, return -1. We hash to the right spot in pidstat_table
and follow the bucket chain to the end. */
static int
bgp_search (pid)
pid_t pid;
{
ps_index_t psi, orig_psi;
if (bgpids.storage == 0 || bgpids.nalloc == 0 || bgpids.npid == 0)
return -1;
/* Search chain using hash to find bucket in pidstat_table */
for (orig_psi = psi = *(pshash_getbucket (pid)); psi != NO_PIDSTAT; psi = bgpids.storage[psi].bucket_next)
{
if (bgpids.storage[psi].pid == pid)
return (bgpids.storage[psi].status);
if (orig_psi == bgpids.storage[psi].bucket_next) /* catch reported bug */
{
internal_warning (_("bgp_search: LOOP: psi (%d) == storage[psi].bucket_next"), psi);
return -1;
}
}
return -1;
}
#if 0
static void
bgp_prune ()
{
return;
}
#endif
/* External interface to bgp_add; takes care of blocking and unblocking
SIGCHLD. Not really used. */
void
save_proc_status (pid, status)
pid_t pid;
int status;
{
sigset_t set, oset;
BLOCK_CHILD (set, oset);
bgp_add (pid, status);
UNBLOCK_CHILD (oset);
}
#if defined (PROCESS_SUBSTITUTION)
/* Functions to add and remove PROCESS * children from the list of running
asynchronous process substitutions. The list is currently a simple singly
linked list of PROCESS *, so it works with the set of callers that want
a child. subst.c:process_substitute adds to the list, the various wait*
functions manipulate child->running and child->status, and processes are
eventually removed from the list and added to the bgpids table. */
static void
procsub_free (p)
PROCESS *p;