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Diffstat (limited to 'nojobs.c')
| -rw-r--r-- | nojobs.c | 938 |
1 files changed, 938 insertions, 0 deletions
diff --git a/nojobs.c b/nojobs.c new file mode 100644 index 0000000..b73e3d6 --- /dev/null +++ b/nojobs.c @@ -0,0 +1,938 @@ +/* nojobs.c - functions that make children, remember them, and handle their termination. */ + +/* This file works under BSD, System V, minix, and Posix systems. It does + not implement job control. */ + +/* Copyright (C) 1987-2009 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 "filecntl.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include <stdio.h> +#include <signal.h> +#include <errno.h> + +#if defined (BUFFERED_INPUT) +# include "input.h" +#endif + +/* Need to include this up here for *_TTY_DRIVER definitions. */ +#include "shtty.h" + +#include "bashintl.h" + +#include "shell.h" +#include "jobs.h" +#include "execute_cmd.h" + +#include "builtins/builtext.h" /* for wait_builtin */ + +#define DEFAULT_CHILD_MAX 32 + +#if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG) +# define killpg(pg, sig) kill(-(pg),(sig)) +#endif /* USG || _POSIX_VERSION */ + +#if !defined (HAVE_SIGINTERRUPT) && !defined (HAVE_POSIX_SIGNALS) +# define siginterrupt(sig, code) +#endif /* !HAVE_SIGINTERRUPT && !HAVE_POSIX_SIGNALS */ + +#if defined (HAVE_WAITPID) +# define WAITPID(pid, statusp, options) waitpid (pid, statusp, options) +#else +# define WAITPID(pid, statusp, options) wait (statusp) +#endif /* !HAVE_WAITPID */ + +/* Return the fd from which we are actually getting input. */ +#define input_tty() (shell_tty != -1) ? shell_tty : fileno (stderr) + +#if !defined (errno) +extern int errno; +#endif /* !errno */ + +extern int interactive, interactive_shell, login_shell; +extern int subshell_environment; +extern int last_command_exit_value, last_command_exit_signal; +extern int interrupt_immediately; +extern sh_builtin_func_t *this_shell_builtin; +#if defined (HAVE_POSIX_SIGNALS) +extern sigset_t top_level_mask; +#endif +extern procenv_t wait_intr_buf; +extern int wait_signal_received; + +pid_t last_made_pid = NO_PID; +pid_t last_asynchronous_pid = NO_PID; + +/* Call this when you start making children. */ +int already_making_children = 0; + +/* The controlling tty for this shell. */ +int shell_tty = -1; + +/* If this is non-zero, $LINES and $COLUMNS are reset after every process + exits from get_tty_state(). */ +int check_window_size; + +/* STATUS and FLAGS are only valid if pid != NO_PID + STATUS is only valid if (flags & PROC_RUNNING) == 0 */ +struct proc_status { + pid_t pid; + int status; /* Exit status of PID or 128 + fatal signal number */ + int flags; +}; + +/* Values for proc_status.flags */ +#define PROC_RUNNING 0x01 +#define PROC_NOTIFIED 0x02 +#define PROC_ASYNC 0x04 +#define PROC_SIGNALED 0x10 + +/* Return values from find_status_by_pid */ +#define PROC_BAD -1 +#define PROC_STILL_ALIVE -2 + +static struct proc_status *pid_list = (struct proc_status *)NULL; +static int pid_list_size; +static int wait_sigint_received; + +static long child_max = -1L; + +static void alloc_pid_list __P((void)); +static int find_proc_slot __P((void)); +static int find_index_by_pid __P((pid_t)); +static int find_status_by_pid __P((pid_t)); +static int process_exit_status __P((WAIT)); +static int find_termsig_by_pid __P((pid_t)); +static int get_termsig __P((WAIT)); +static void set_pid_status __P((pid_t, WAIT)); +static void set_pid_flags __P((pid_t, int)); +static void unset_pid_flags __P((pid_t, int)); +static int get_pid_flags __P((pid_t)); +static void add_pid __P((pid_t, int)); +static void mark_dead_jobs_as_notified __P((int)); + +static sighandler wait_sigint_handler __P((int)); +static char *j_strsignal __P((int)); + +#if defined (HAVE_WAITPID) +static void reap_zombie_children __P((void)); +#endif + +#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS) +static int siginterrupt __P((int, int)); +#endif + +static void restore_sigint_handler __P((void)); + +/* Allocate new, or grow existing PID_LIST. */ +static void +alloc_pid_list () +{ + register int i; + int old = pid_list_size; + + pid_list_size += 10; + pid_list = (struct proc_status *)xrealloc (pid_list, pid_list_size * sizeof (struct proc_status)); + + /* None of the newly allocated slots have process id's yet. */ + for (i = old; i < pid_list_size; i++) + pid_list[i].pid = NO_PID; +} + +/* Return the offset within the PID_LIST array of an empty slot. This can + create new slots if all of the existing slots are taken. */ +static int +find_proc_slot () +{ + register int i; + + for (i = 0; i < pid_list_size; i++) + if (pid_list[i].pid == NO_PID) + return (i); + + if (i == pid_list_size) + alloc_pid_list (); + + return (i); +} + +/* Return the offset within the PID_LIST array of a slot containing PID, + or the value NO_PID if the pid wasn't found. */ +static int +find_index_by_pid (pid) + pid_t pid; +{ + register int i; + + for (i = 0; i < pid_list_size; i++) + if (pid_list[i].pid == pid) + return (i); + + return (NO_PID); +} + +/* Return the status of PID as looked up in the PID_LIST array. A + return value of PROC_BAD indicates that PID wasn't found. */ +static int +find_status_by_pid (pid) + pid_t pid; +{ + int i; + + i = find_index_by_pid (pid); + if (i == NO_PID) + return (PROC_BAD); + if (pid_list[i].flags & PROC_RUNNING) + return (PROC_STILL_ALIVE); + return (pid_list[i].status); +} + +static int +process_exit_status (status) + WAIT status; +{ + if (WIFSIGNALED (status)) + return (128 + WTERMSIG (status)); + else + return (WEXITSTATUS (status)); +} + +/* Return the status of PID as looked up in the PID_LIST array. A + return value of PROC_BAD indicates that PID wasn't found. */ +static int +find_termsig_by_pid (pid) + pid_t pid; +{ + int i; + + i = find_index_by_pid (pid); + if (i == NO_PID) + return (0); + if (pid_list[i].flags & PROC_RUNNING) + return (0); + return (get_termsig ((WAIT)pid_list[i].status)); +} + +/* Set LAST_COMMAND_EXIT_SIGNAL depending on STATUS. If STATUS is -1, look + up PID in the pid array and set LAST_COMMAND_EXIT_SIGNAL appropriately + depending on its flags and exit status. */ +static int +get_termsig (status) + WAIT status; +{ + if (WIFSTOPPED (status) == 0 && WIFSIGNALED (status)) + return (WTERMSIG (status)); + else + return (0); +} + +/* Give PID the status value STATUS in the PID_LIST array. */ +static void +set_pid_status (pid, status) + pid_t pid; + WAIT status; +{ + int slot; + +#if defined (COPROCESS_SUPPORT) + coproc_pidchk (pid, status); +#endif + + slot = find_index_by_pid (pid); + if (slot == NO_PID) + return; + + pid_list[slot].status = process_exit_status (status); + pid_list[slot].flags &= ~PROC_RUNNING; + if (WIFSIGNALED (status)) + pid_list[slot].flags |= PROC_SIGNALED; + /* If it's not a background process, mark it as notified so it gets + cleaned up. */ + if ((pid_list[slot].flags & PROC_ASYNC) == 0) + pid_list[slot].flags |= PROC_NOTIFIED; +} + +/* Give PID the flags FLAGS in the PID_LIST array. */ +static void +set_pid_flags (pid, flags) + pid_t pid; + int flags; +{ + int slot; + + slot = find_index_by_pid (pid); + if (slot == NO_PID) + return; + + pid_list[slot].flags |= flags; +} + +/* Unset FLAGS for PID in the pid list */ +static void +unset_pid_flags (pid, flags) + pid_t pid; + int flags; +{ + int slot; + + slot = find_index_by_pid (pid); + if (slot == NO_PID) + return; + + pid_list[slot].flags &= ~flags; +} + +/* Return the flags corresponding to PID in the PID_LIST array. */ +static int +get_pid_flags (pid) + pid_t pid; +{ + int slot; + + slot = find_index_by_pid (pid); + if (slot == NO_PID) + return 0; + + return (pid_list[slot].flags); +} + +static void +add_pid (pid, async) + pid_t pid; + int async; +{ + int slot; + + slot = find_proc_slot (); + + pid_list[slot].pid = pid; + pid_list[slot].status = -1; + pid_list[slot].flags = PROC_RUNNING; + if (async) + pid_list[slot].flags |= PROC_ASYNC; +} + +static void +mark_dead_jobs_as_notified (force) + int force; +{ + register int i, ndead; + + /* first, count the number of non-running async jobs if FORCE == 0 */ + for (i = ndead = 0; force == 0 && i < pid_list_size; i++) + { + if (pid_list[i].pid == NO_PID) + continue; + if (((pid_list[i].flags & PROC_RUNNING) == 0) && + (pid_list[i].flags & PROC_ASYNC)) + ndead++; + } + + if (child_max < 0) + child_max = getmaxchild (); + if (child_max < 0) + child_max = DEFAULT_CHILD_MAX; + + if (force == 0 && ndead <= child_max) + return; + + /* If FORCE == 0, we just mark as many non-running async jobs as notified + to bring us under the CHILD_MAX limit. */ + for (i = 0; i < pid_list_size; i++) + { + if (pid_list[i].pid == NO_PID) + continue; + if (((pid_list[i].flags & PROC_RUNNING) == 0) && + pid_list[i].pid != last_asynchronous_pid) + { + pid_list[i].flags |= PROC_NOTIFIED; + if (force == 0 && (pid_list[i].flags & PROC_ASYNC) && --ndead <= child_max) + break; + } + } +} + +/* Remove all dead, notified jobs from the pid_list. */ +int +cleanup_dead_jobs () +{ + register int i; + +#if defined (HAVE_WAITPID) + reap_zombie_children (); +#endif + + for (i = 0; i < pid_list_size; i++) + { + if ((pid_list[i].flags & PROC_RUNNING) == 0 && + (pid_list[i].flags & PROC_NOTIFIED)) + pid_list[i].pid = NO_PID; + } + +#if defined (COPROCESS_SUPPORT) + coproc_reap (); +#endif + + return 0; +} + +void +reap_dead_jobs () +{ + mark_dead_jobs_as_notified (0); + cleanup_dead_jobs (); +} + +/* Initialize the job control mechanism, and set up the tty stuff. */ +initialize_job_control (force) + int force; +{ + shell_tty = fileno (stderr); + + if (interactive) + get_tty_state (); +} + +/* Setup this shell to handle C-C, etc. */ +void +initialize_job_signals () +{ + set_signal_handler (SIGINT, sigint_sighandler); + + /* If this is a login shell we don't wish to be disturbed by + stop signals. */ + if (login_shell) + ignore_tty_job_signals (); +} + +#if defined (HAVE_WAITPID) +/* Collect the status of all zombie children so that their system + resources can be deallocated. */ +static void +reap_zombie_children () +{ +# if defined (WNOHANG) + pid_t pid; + WAIT status; + + CHECK_TERMSIG; + while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0) + set_pid_status (pid, status); +# endif /* WNOHANG */ + CHECK_TERMSIG; +} +#endif /* WAITPID */ + +#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS) +static int +siginterrupt (sig, flag) + int sig, flag; +{ + struct sigaction act; + + sigaction (sig, (struct sigaction *)NULL, &act); + + if (flag) + act.sa_flags &= ~SA_RESTART; + else + act.sa_flags |= SA_RESTART; + + return (sigaction (sig, &act, (struct sigaction *)NULL)); +} +#endif /* !HAVE_SIGINTERRUPT && HAVE_POSIX_SIGNALS */ + +/* Fork, handling errors. Returns the pid of the newly made child, or 0. + COMMAND is just for remembering the name of the command; we don't do + anything else with it. ASYNC_P says what to do with the tty. If + non-zero, then don't give it away. */ +pid_t +make_child (command, async_p) + char *command; + int async_p; +{ + pid_t pid; + int forksleep; + + /* Discard saved memory. */ + if (command) + free (command); + + start_pipeline (); + +#if defined (BUFFERED_INPUT) + /* If default_buffered_input is active, we are reading a script. If + the command is asynchronous, we have already duplicated /dev/null + as fd 0, but have not changed the buffered stream corresponding to + the old fd 0. We don't want to sync the stream in this case. */ + if (default_buffered_input != -1 && (!async_p || default_buffered_input > 0)) + sync_buffered_stream (default_buffered_input); +#endif /* BUFFERED_INPUT */ + + /* Create the child, handle severe errors. Retry on EAGAIN. */ + forksleep = 1; + while ((pid = fork ()) < 0 && errno == EAGAIN && forksleep < FORKSLEEP_MAX) + { + sys_error ("fork: retry"); +#if defined (HAVE_WAITPID) + /* Posix systems with a non-blocking waitpid () system call available + get another chance after zombies are reaped. */ + reap_zombie_children (); + if (forksleep > 1 && sleep (forksleep) != 0) + break; +#else + if (sleep (forksleep) != 0) + break; +#endif /* HAVE_WAITPID */ + forksleep <<= 1; + } + + if (pid < 0) + { + sys_error ("fork"); + throw_to_top_level (); + } + + if (pid == 0) + { +#if defined (BUFFERED_INPUT) + unset_bash_input (0); +#endif /* BUFFERED_INPUT */ + +#if defined (HAVE_POSIX_SIGNALS) + /* Restore top-level signal mask. */ + sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL); +#endif + +#if 0 + /* Ignore INT and QUIT in asynchronous children. */ + if (async_p) + last_asynchronous_pid = getpid (); +#endif + + default_tty_job_signals (); + } + else + { + /* In the parent. */ + + last_made_pid = pid; + + if (async_p) + last_asynchronous_pid = pid; + + add_pid (pid, async_p); + } + return (pid); +} + +void +ignore_tty_job_signals () +{ +#if defined (SIGTSTP) + set_signal_handler (SIGTSTP, SIG_IGN); + set_signal_handler (SIGTTIN, SIG_IGN); + set_signal_handler (SIGTTOU, SIG_IGN); +#endif +} + +void +default_tty_job_signals () +{ +#if defined (SIGTSTP) + set_signal_handler (SIGTSTP, SIG_DFL); + set_signal_handler (SIGTTIN, SIG_DFL); + set_signal_handler (SIGTTOU, SIG_DFL); +#endif +} + +/* Wait for a single pid (PID) and return its exit status. Called by + the wait builtin. */ +int +wait_for_single_pid (pid) + pid_t pid; +{ + pid_t got_pid; + WAIT status; + int pstatus, flags; + + pstatus = find_status_by_pid (pid); + + if (pstatus == PROC_BAD) + { + internal_error (_("wait: pid %ld is not a child of this shell"), (long)pid); + return (127); + } + + if (pstatus != PROC_STILL_ALIVE) + { + if (pstatus > 128) + last_command_exit_signal = find_termsig_by_pid (pid); + return (pstatus); + } + + siginterrupt (SIGINT, 1); + while ((got_pid = WAITPID (pid, &status, 0)) != pid) + { + CHECK_TERMSIG; + if (got_pid < 0) + { + if (errno != EINTR && errno != ECHILD) + { + siginterrupt (SIGINT, 0); + sys_error ("wait"); + } + break; + } + else if (got_pid > 0) + set_pid_status (got_pid, status); + } + + if (got_pid > 0) + { + set_pid_status (got_pid, status); + set_pid_flags (got_pid, PROC_NOTIFIED); + } + + siginterrupt (SIGINT, 0); + QUIT; + + return (got_pid > 0 ? process_exit_status (status) : -1); +} + +/* Wait for all of the shell's children to exit. Called by the `wait' + builtin. */ +void +wait_for_background_pids () +{ + pid_t got_pid; + WAIT status; + + /* If we aren't using job control, we let the kernel take care of the + bookkeeping for us. wait () will return -1 and set errno to ECHILD + when there are no more unwaited-for child processes on both + 4.2 BSD-based and System V-based systems. */ + + siginterrupt (SIGINT, 1); + + /* Wait for ECHILD */ + while ((got_pid = WAITPID (-1, &status, 0)) != -1) + set_pid_status (got_pid, status); + + if (errno != EINTR && errno != ECHILD) + { + siginterrupt (SIGINT, 0); + sys_error("wait"); + } + + siginterrupt (SIGINT, 0); + QUIT; + + mark_dead_jobs_as_notified (1); + cleanup_dead_jobs (); +} + +/* Make OLD_SIGINT_HANDLER the SIGINT signal handler. */ +#define INVALID_SIGNAL_HANDLER (SigHandler *)wait_for_background_pids +static SigHandler *old_sigint_handler = INVALID_SIGNAL_HANDLER; + +static void +restore_sigint_handler () +{ + if (old_sigint_handler != INVALID_SIGNAL_HANDLER) + { + set_signal_handler (SIGINT, old_sigint_handler); + old_sigint_handler = INVALID_SIGNAL_HANDLER; + } +} + +/* Handle SIGINT while we are waiting for children in a script to exit. + All interrupts are effectively ignored by the shell, but allowed to + kill a running job. */ +static sighandler +wait_sigint_handler (sig) + int sig; +{ + SigHandler *sigint_handler; + + /* If we got a SIGINT while in `wait', and SIGINT is trapped, do + what POSIX.2 says (see builtins/wait.def for more info). */ + if (this_shell_builtin && this_shell_builtin == wait_builtin && + signal_is_trapped (SIGINT) && + ((sigint_handler = trap_to_sighandler (SIGINT)) == trap_handler)) + { + last_command_exit_value = EXECUTION_FAILURE; + restore_sigint_handler (); + interrupt_immediately = 0; + trap_handler (SIGINT); /* set pending_traps[SIGINT] */ + wait_signal_received = SIGINT; + longjmp (wait_intr_buf, 1); + } + + if (interrupt_immediately) + { + last_command_exit_value = EXECUTION_FAILURE; + restore_sigint_handler (); + ADDINTERRUPT; + QUIT; + } + + wait_sigint_received = 1; + + SIGRETURN (0); +} + +static char * +j_strsignal (s) + int s; +{ + static char retcode_name_buffer[64] = { '\0' }; + char *x; + + x = strsignal (s); + if (x == 0) + { + x = retcode_name_buffer; + sprintf (x, "Signal %d", s); + } + return x; +} + +/* Wait for pid (one of our children) to terminate. This is called only + by the execution code in execute_cmd.c. */ +int +wait_for (pid) + pid_t pid; +{ + int return_val, pstatus; + pid_t got_pid; + WAIT status; + + pstatus = find_status_by_pid (pid); + + if (pstatus == PROC_BAD) + return (0); + + if (pstatus != PROC_STILL_ALIVE) + { + if (pstatus > 128) + last_command_exit_signal = find_termsig_by_pid (pid); + return (pstatus); + } + + /* If we are running a script, ignore SIGINT while we're waiting for + a child to exit. The loop below does some of this, but not all. */ + wait_sigint_received = 0; + if (interactive_shell == 0) + old_sigint_handler = set_signal_handler (SIGINT, wait_sigint_handler); + + while ((got_pid = WAITPID (-1, &status, 0)) != pid) /* XXX was pid now -1 */ + { + CHECK_TERMSIG; + if (got_pid < 0 && errno == ECHILD) + { +#if !defined (_POSIX_VERSION) + status.w_termsig = status.w_retcode = 0; +#else + status = 0; +#endif /* _POSIX_VERSION */ + break; + } + else if (got_pid < 0 && errno != EINTR) + programming_error ("wait_for(%ld): %s", (long)pid, strerror(errno)); + else if (got_pid > 0) + set_pid_status (got_pid, status); + } + + if (got_pid > 0) + set_pid_status (got_pid, status); + +#if defined (HAVE_WAITPID) + if (got_pid >= 0) + reap_zombie_children (); +#endif /* HAVE_WAITPID */ + + if (interactive_shell == 0) + { + SigHandler *temp_handler; + + temp_handler = old_sigint_handler; + restore_sigint_handler (); + + /* If the job exited because of SIGINT, make sure the shell acts as if + it had received one also. */ + if (WIFSIGNALED (status) && (WTERMSIG (status) == SIGINT)) + { + + if (maybe_call_trap_handler (SIGINT) == 0) + { + if (temp_handler == SIG_DFL) + termsig_handler (SIGINT); + else if (temp_handler != INVALID_SIGNAL_HANDLER && temp_handler != SIG_IGN) + (*temp_handler) (SIGINT); + } + } + } + + /* Default return value. */ + /* ``a full 8 bits of status is returned'' */ + return_val = process_exit_status (status); + last_command_exit_signal = get_termsig (status); + +#if !defined (DONT_REPORT_SIGPIPE) + if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) && + (WTERMSIG (status) != SIGINT)) +#else + if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) && + (WTERMSIG (status) != SIGINT) && (WTERMSIG (status) != SIGPIPE)) +#endif + { + fprintf (stderr, "%s", j_strsignal (WTERMSIG (status))); + if (WIFCORED (status)) + fprintf (stderr, _(" (core dumped)")); + fprintf (stderr, "\n"); + } + + if (interactive_shell && subshell_environment == 0) + { + if (WIFSIGNALED (status) || WIFSTOPPED (status)) + set_tty_state (); + else + get_tty_state (); + } + + return (return_val); +} + +/* Send PID SIGNAL. Returns -1 on failure, 0 on success. If GROUP is non-zero, + or PID is less than -1, then kill the process group associated with PID. */ +int +kill_pid (pid, signal, group) + pid_t pid; + int signal, group; +{ + int result; + + if (pid < -1) + { + pid = -pid; + group = 1; + } + result = group ? killpg (pid, signal) : kill (pid, signal); + return (result); +} + +static TTYSTRUCT shell_tty_info; +static int got_tty_state; + +/* Fill the contents of shell_tty_info with the current tty info. */ +get_tty_state () +{ + int tty; + + tty = input_tty (); + if (tty != -1) + { + ttgetattr (tty, &shell_tty_info); + got_tty_state = 1; + if (check_window_size) + get_new_window_size (0, (int *)0, (int *)0); + } +} + +/* Make the current tty use the state in shell_tty_info. */ +int +set_tty_state () +{ + int tty; + + tty = input_tty (); + if (tty != -1) + { + if (got_tty_state == 0) + return 0; + ttsetattr (tty, &shell_tty_info); + } + return 0; +} + +/* Give the terminal to PGRP. */ +give_terminal_to (pgrp, force) + pid_t pgrp; + int force; +{ +} + +/* Stop a pipeline. */ +int +stop_pipeline (async, ignore) + int async; + COMMAND *ignore; +{ + already_making_children = 0; + return 0; +} + +void +start_pipeline () +{ + already_making_children = 1; +} + +void +stop_making_children () +{ + already_making_children = 0; +} + +int +get_job_by_pid (pid, block) + pid_t pid; + int block; +{ + int i; + + i = find_index_by_pid (pid); + return ((i == NO_PID) ? PROC_BAD : i); +} + +/* Print descriptive information about the job with leader pid PID. */ +void +describe_pid (pid) + pid_t pid; +{ + fprintf (stderr, "%ld\n", (long) pid); +} + +void +unfreeze_jobs_list () +{ +} + +int +count_all_jobs () +{ + return 0; +} |