read builtin timeouts no longer use SIGALRM

CWRU/CWRU.chlog

@@ -9726,3 +9726,34 @@ parse.y,shell.h
 	- {save,restore}_parser_state: save amd restore shell_eof_token and
 	  pushed_string_list; change callers (e.g., xparse_dolparen) so they
 	  don't have to manage them
+
+				   3/10
+				   ----
+builtins/common.h
+	- extern declarations for moving to timers (sh_timer) for read builtin
+	  timeouts
+
+quit.h
+	- CHECK_ALRM: remove, no longer used
+
+trap.c
+	- check_signals: call check_read_timeout instead of CHECK_ALRM
+
+bashline.c
+	- bash_event_hook: use read_timeout instead of checking `sigalrm_seen';
+	  that no longer exists
+	- bash_event_hook: accommodate readline timing out (not used yet)
+
+lib/sh/zread.c
+	- zread: call read_builtin_timeout() to check for a timeout before
+	  calling a blocking read()
+	  
+builtins/read.def
+	- sigalrm,reset_timeout,check_read_timeout,read_builtin_timeout: new
+	  and modified functions to use sh_timers for timeouts instead of
+	  SIGALRM. Based on work contributed by Koichi Murase
+	  <myoga.murase@gmail.com>
+	- read_builtin: use sh_timers for read timeouts (-t N) instead of
+	  using SIGALRM
+	- edit_line: simulate receiving SIGALRM if readline times out (not
+	  used yet)

MANIFEST

@@ -368,6 +368,7 @@ lib/readline/posixdir.h	f
 lib/readline/posixjmp.h	f
 lib/readline/posixselect.h	f
 lib/readline/posixstat.h	f
+lib/readline/posixtime.h	f
 lib/readline/ansi_stdlib.h	f
 lib/readline/rlstdc.h	f
 lib/readline/rlprivate.h	f
@@ -868,11 +869,11 @@ examples/misc/cshtobash	f
 examples/shellmath/LICENSE	f
 examples/shellmath/README.md	f
 examples/shellmath/assert.sh	f
-examples/shellmath/faster_e_demo.sh*	f
+examples/shellmath/faster_e_demo.sh	f
 examples/shellmath/image.png	f
 examples/shellmath/runTests.sh	f
 examples/shellmath/shellmath.sh	f
-examples/shellmath/slower_e_demo.sh*	f
+examples/shellmath/slower_e_demo.sh	f
 examples/shellmath/testCases.in	f
 examples/shellmath/timingData.txt	f
 tests/README		f

bashline.c

@@ -1,6 +1,6 @@
 /* bashline.c -- Bash's interface to the readline library. */
 
-/* Copyright (C) 1987-2020 Free Software Foundation, Inc.
+/* Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -56,6 +56,7 @@
 #include "shmbutil.h"
 #include "trap.h"
 #include "flags.h"
+#include "timer.h"
 
 #if defined (HAVE_MBSTR_H) && defined (HAVE_MBSCHR)
 #  include <mbstr.h>		/* mbschr */
@@ -225,6 +226,7 @@ static char **prog_complete_matches;
 
 extern int no_symbolic_links;
 extern STRING_INT_ALIST word_token_alist[];
+extern sh_timer *read_timeout;
 
 /* SPECIFIC_COMPLETION_FUNCTIONS specifies that we have individual
    completion functions which indicate what type of completion should be
@@ -4627,19 +4629,27 @@ bash_event_hook ()
     sig = terminating_signal;
   else if (interrupt_state)
     sig = SIGINT;
-  else if (sigalrm_seen)
+  else if (read_timeout && read_timeout->alrmflag)
     sig = SIGALRM;
+  else if (RL_ISSTATE (RL_STATE_TIMEOUT))		/* just in case */
+    {
+      sig = SIGALRM;
+      if (read_timeout)
+	read_timeout->alrmflag = 1;
+    }
   else
     sig = first_pending_trap ();
 
   /* If we're going to longjmp to top_level, make sure we clean up readline.
      check_signals will call QUIT, which will eventually longjmp to top_level,
-     calling run_interrupt_trap along the way.  The check for sigalrm_seen is
-     to clean up the read builtin's state. */
-  if (terminating_signal || interrupt_state || sigalrm_seen)
+     calling run_interrupt_trap along the way.  The check against read_timeout
+     is so we can clean up the read builtin's state. */
+  if (terminating_signal || interrupt_state || (read_timeout && read_timeout->alrmflag))
     rl_cleanup_after_signal ();
   bashline_reset_event_hook ();
 
+  RL_UNSETSTATE (RL_STATE_TIMEOUT);			/* XXX */
+
   /* posix mode SIGINT during read -e. We only get here if SIGINT is trapped. */
   if (posixly_correct && this_shell_builtin == read_builtin && sig == SIGINT)
     {

builtins/common.h

@@ -1,6 +1,6 @@
 /* common.h -- extern declarations for functions defined in common.c. */
 
-/* Copyright (C) 1993-2020 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -151,6 +151,9 @@ extern void builtin_help PARAMS((void));
 extern void read_tty_cleanup PARAMS((void));
 extern int read_tty_modified PARAMS((void));
 
+extern int read_builtin_timeout PARAMS((int));
+extern void check_read_timeout PARAMS((void));
+
 /* Functions from set.def */
 extern int minus_o_option_value PARAMS((char *));
 extern void list_minus_o_opts PARAMS((int, int));
@@ -236,9 +239,6 @@ extern int breaking;
 extern int continuing;
 extern int loop_level;
 
-/* variables from read.def */
-extern int sigalrm_seen;
-
 /* variables from shift.def */
 extern int print_shift_error;
 

builtins/read.def

@@ -1,7 +1,7 @@
 This file is read.def, from which is created read.c.
 It implements the builtin "read" in Bash.
 
-Copyright (C) 1987-2020 Free Software Foundation, Inc.
+Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
 This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -108,6 +108,7 @@ $END
 #endif
 
 #include "shmbutil.h"
+#include "timer.h"
 
 #if !defined(errno)
 extern int errno;
@@ -133,11 +134,10 @@ static int read_mbchar PARAMS((int, char *, int, int, int));
 static void ttyrestore PARAMS((struct ttsave *));
 
 static sighandler sigalrm PARAMS((int));
-static void reset_alarm PARAMS((void));
+static void reset_timeout PARAMS((void));
 
 /* Try this to see what the rest of the shell can do with the information. */
-procenv_t alrmbuf;
-int sigalrm_seen;
+sh_timer *read_timeout;
 
 static int reading, tty_modified;
 static SigHandler *old_alrm;
@@ -149,21 +149,44 @@ static struct ttsave termsave;
    avoids problems with the semi-tricky stuff we do with the xfree of
    input_string at the top of the unwind-protect list (see below). */
 
-/* Set a flag that CHECK_ALRM can check.  This relies on zread or read_builtin
-   calling trap.c:check_signals(), which knows about sigalrm_seen and alrmbuf. */
+/* Set a flag that check_read_timeout can check.  This relies on zread or
+   read_builtin calling trap.c:check_signals() (which calls check_read_timeout()) */
 static sighandler
 sigalrm (s)
      int s;
 {
-  sigalrm_seen = 1;
+  /* Display warning if this is called without read_timeout set? */
+  if (read_timeout)
+    read_timeout->alrmflag = 1;
 }
 
 static void
-reset_alarm ()
+reset_timeout ()
 {
   /* Cancel alarm before restoring signal handler. */
-  falarm (0, 0);
-  set_signal_handler (SIGALRM, old_alrm);
+  if (read_timeout)
+    shtimer_clear (read_timeout);
+  read_timeout = 0;
+}
+
+void
+check_read_timeout ()
+{
+  if (read_timeout && shtimer_chktimeout (read_timeout))
+    sh_longjmp (read_timeout->jmpenv, 1);
+}
+
+int
+read_builtin_timeout (fd)
+     int fd;
+{
+  if ((read_timeout == 0) ||
+      (read_timeout->fd != fd) ||
+      (read_timeout->tmout.tv_sec == 0 && read_timeout->tmout.tv_usec == 0))
+    return 0;
+
+  return ((read_timeout->flags & SHTIMER_ALARM) ? shtimer_alrm (read_timeout)
+  						: shtimer_select (read_timeout));
 }
 
 /* Read the value of the shell variables whose names follow.
@@ -227,7 +250,8 @@ read_builtin (list)
   USE_VAR(ps2);
   USE_VAR(lastsig);
 
-  sigalrm_seen = reading = tty_modified = 0;
+  reading = tty_modified = 0;
+  read_timeout = 0;
 
   i = 0;		/* Index into the string that we are reading. */
   raw = edit = 0;	/* Not reading raw input by default. */
@@ -332,11 +356,7 @@ read_builtin (list)
   /* `read -t 0 var' tests whether input is available with select/FIONREAD,
      and fails if those are unavailable */
   if (have_timeout && tmsec == 0 && tmusec == 0)
-#if 0
-    return (EXECUTION_FAILURE);
-#else
     return (input_avail (fd) ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
-#endif
 
   /* Convenience: check early whether or not the first of possibly several
      variable names is a valid identifier, and bail early if so. */
@@ -392,7 +412,7 @@ read_builtin (list)
 #if defined (SIGCHLD)
   sigemptyset (&chldset);
   sigprocmask (SIG_BLOCK, (sigset_t *)0, &chldset);
-  sigaddset (&chldset, SIGCHLD); 
+  sigaddset (&chldset, SIGCHLD);
 #endif
 
   begin_unwind_frame ("read_builtin");
@@ -443,10 +463,25 @@ read_builtin (list)
 
   if (tmsec > 0 || tmusec > 0)
     {
-      code = setjmp_nosigs (alrmbuf);
+      read_timeout = shtimer_alloc ();
+      read_timeout->flags = SHTIMER_LONGJMP;
+
+#if defined (HAVE_SELECT)
+      read_timeout->flags |= edit ? SHTIMER_ALARM : SHTIMER_SELECT;
+#else
+      read_timeout->flags |= SHTIMER_ALARM;
+#endif
+      read_timeout->fd = fd;
+
+      read_timeout->alrm_handler = sigalrm;
+    }
+
+  if (tmsec > 0 || tmusec > 0)
+    {
+      code = setjmp_nosigs (read_timeout->jmpenv);
       if (code)
 	{
-	  sigalrm_seen = 0;
+	  reset_timeout ();
 	  sigprocmask (SIG_SETMASK, &prevset, (sigset_t *)0);
 
 	  /* Tricky.  The top of the unwind-protect stack is the free of
@@ -470,8 +505,7 @@ read_builtin (list)
 	}
       if (interactive_shell == 0)
 	initialize_terminating_signals ();
-      old_alrm = set_signal_handler (SIGALRM, sigalrm);
-      add_unwind_protect (reset_alarm, (char *)NULL);
+      add_unwind_protect (reset_timeout, (char *)NULL);
 #if defined (READLINE)
       if (edit)
 	{
@@ -479,8 +513,7 @@ read_builtin (list)
 	  add_unwind_protect (bashline_reset_event_hook, (char *)NULL);
 	}
 #endif
-      sigprocmask (SIG_BLOCK, (sigset_t *)0, &prevset);
-      falarm (tmsec, tmusec);
+      shtimer_set (read_timeout, tmsec, tmusec);
     }
 
   /* If we've been asked to read only NCHARS chars, or we're using some
@@ -556,7 +589,7 @@ read_builtin (list)
      of the unwind-protect stack after the realloc() works right. */
   add_unwind_protect (xfree, input_string);
 
-  CHECK_ALRM;
+  check_read_timeout ();
   if ((nchars > 0) && (input_is_tty == 0) && ignore_delim)	/* read -N */
     unbuffered_read = 2;
   else if ((nchars > 0) || (delim != '\n') || input_is_pipe)
@@ -575,7 +608,7 @@ read_builtin (list)
   ps2 = 0;
   for (print_ps2 = eof = retval = 0;;)
     {
-      CHECK_ALRM;
+      check_read_timeout ();
 
 #if defined (READLINE)
       if (edit)
@@ -622,7 +655,7 @@ read_builtin (list)
 	}
 
       reading = 1;
-      CHECK_ALRM;
+      check_read_timeout ();
       errno = 0;
 
 #if defined (SIGCHLD)
@@ -673,7 +706,7 @@ read_builtin (list)
 #endif
 
       if (retval <= 0)			/* XXX shouldn't happen */
-	CHECK_ALRM;
+	check_read_timeout ();
 
       /* XXX -- use i + mb_cur_max (at least 4) for multibyte/read_mbchar */
       if (i + (mb_cur_max > 4 ? mb_cur_max : 4) >= size)
@@ -733,7 +766,7 @@ read_builtin (list)
 
 add_char:
       input_string[i++] = c;
-      CHECK_ALRM;
+      check_read_timeout ();
 
 #if defined (HANDLE_MULTIBYTE)
       /* XXX - what if C == 127? Can DEL introduce a multibyte sequence? */
@@ -770,7 +803,7 @@ add_char:
 	break;
     }
   input_string[i] = '\0';
-  CHECK_ALRM;
+  check_read_timeout ();
 
 #if defined (READLINE)
   if (edit)
@@ -787,7 +820,7 @@ add_char:
     }
 
   if (tmsec > 0 || tmusec > 0)
-    reset_alarm ();
+    reset_timeout ();
 
   if (nchars > 0 || delim != '\n')
     {
@@ -1160,7 +1193,15 @@ edit_line (p, itext)
   bashline_reset_event_hook ();
 
   if (ret == 0)
-    return ret;
+    {
+      if (RL_ISSTATE (RL_STATE_TIMEOUT))
+	{
+	  sigalrm (SIGALRM);		/* simulate receiving SIGALRM */
+	  check_read_timeout ();
+	}
+      return ret;
+    }
+
   len = strlen (ret);
   ret = (char *)xrealloc (ret, len + 2);
   ret[len++] = delim;

examples/shellmath/faster_e_demo.sh*

@@ -1,68 +0,0 @@
-#!/usr/bin/env bash
-
-###############################################################################
-# This script performs the same task as "slower_e_demo.sh" but with a major
-# performance optimization. The speedup is especially noticeable on GNU
-# emulation layers for Windows such as Cygwin and minGW, where the overhead
-# of subshelling is quite significant.
-#
-# The speedup uses global storage space to simulate pass-and-return by
-# reference so that you can capture the side effects of a function call without
-# writing to stdout and wrapping the call in a subshell. How to use:
-#
-#    Turn on  "__shellmath_isOptimized"  as shown below.
-#    Then instead of invoking  "mySum = $(_shellmath_add  $x  $y)",
-#    call  "_shellmath_add  $x  $y;  _shellmath_getReturnValue  mySum".
-###############################################################################
-
-source shellmath.sh
-
-# Setting the '-t' flag will cause the script to time the algorithm
-if [[ "$1" == '-t' ]]; then
-    do_timing=${__shellmath_true}
-    shift
-fi
-
-if [[ $# -ne 1 ]]; then
-    echo "USAGE: ${BASH_SOURCE##*/}  [-t]  *N*"
-    echo "       Approximates 'e' using the N-th order Maclaurin polynomial"
-    echo "       (i.e. the Taylor polynomial centered at 0)."
-    echo "       Specify the '-t' flag to time the main algorithm."
-    exit 0
-elif [[ ! "$1" =~ ^[0-9]+$ ]]; then
-    echo "Illegal argument. Whole numbers only, please."
-    exit 1
-fi
-
-__shellmath_isOptimized=${__shellmath_true}
-
-
-function run_algorithm()
-{
-    # Initialize
-    n=0;  N=$1;  zero_factorial=1
-
-    # Initialize "e" to its zeroth-order term
-    _shellmath_divide  1  $zero_factorial
-    _shellmath_getReturnValue term
-    e=$term
-
-    # Compute successive terms T(n) := T(n-1)/n and accumulate into e
-    for ((n=1; n<=N; n++)); do
-        _shellmath_divide  "$term"  "$n"
-        _shellmath_getReturnValue term
-        _shellmath_add  "$e"  "$term"
-        _shellmath_getReturnValue e
-    done
-
-    echo "e = $e"
-}
-
-if (( do_timing == __shellmath_true )); then
-    time run_algorithm "$1"
-else
-    run_algorithm "$1"
-fi
-
-exit 0
-

examples/shellmath/slower_e_demo.sh*

@@ -1,55 +0,0 @@
-#!/usr/bin/env bash
-
-###############################################################################
-# This script illustrates the use of the shellmath APIs to perform
-# decimal calculations. Here we approximate the mathematical constant 'e'
-# using its Maclaurin polynomials (i.e. its Taylor polynomials centered at 0).
-###############################################################################
-
-source shellmath.sh
-
-# Setting the '-t' flag will cause the script to time the algorithm
-if [[ "$1" == '-t' ]]; then
-    do_timing=${__shellmath_true}
-    shift
-fi
-
-if [[ $# -ne 1 ]]; then
-    echo "USAGE: ${BASH_SOURCE##*/}  [-t]  *N*"
-    echo "       Approximates 'e' using the N-th order Maclaurin polynomial"
-    echo "       (i.e. the Taylor polynomial centered at 0)."
-    echo "       Specify the '-t' flag to time the main algorithm."
-    exit 0
-elif [[ ! "$1" =~ ^[0-9]+$ ]]; then
-    echo "Illegal argument. Whole numbers only, please."
-    exit 1
-fi
-
-
-function run_algorithm()
-{
-    # Initialize
-    n=0;  N=$1;  zero_factorial=1
-
-    # Initialize e to the zeroth-order term
-    term=$(_shellmath_divide  1  $zero_factorial)
-    e=$term
-
-    # Compute successive terms T(n) := T(n-1)/n and accumulate into e
-    for ((n=1; n<=N; n++)); do
-        term=$(_shellmath_divide  "$term"  "$n")
-        e=$(_shellmath_add  "$e"  "$term")
-    done
-
-    echo "e = $e"
-}
-
-
-if (( do_timing == __shellmath_true )); then
-    time run_algorithm "$1"
-else
-    run_algorithm "$1"
-fi
-
-exit 0
-

include/posixtime.h

@@ -72,8 +72,8 @@ extern int gettimeofday PARAMS((struct timeval *, void *));
 #endif
 
 /* These are non-standard. */
-#if !defined (timerunset)
-#  define timerunset(tvp)	((tvp)->tv_sec == 0 && (tvp)->tv_usec == 0)
+#if !defined (timerisunset)
+#  define timerisunset(tvp)	((tvp)->tv_sec == 0 && (tvp)->tv_usec == 0)
 #endif
 #if !defined (timerset)
 #  define timerset(tvp, s, u)	do { tvp->tv_sec = s; tvp->tv_usec = u; } while (0)

lib/readline/readline.h

@@ -906,6 +906,7 @@ extern int rl_persistent_signal_handlers;
 #define RL_STATE_REDISPLAYING	0x1000000	/* updating terminal display */
 
 #define RL_STATE_DONE		0x2000000	/* done; accepted line */
+#define RL_STATE_TIMEOUT	0x4000000	/* readline() timed out */
 
 #define RL_SETSTATE(x)		(rl_readline_state |= (x))
 #define RL_UNSETSTATE(x)	(rl_readline_state &= ~(x))

lib/sh/zread.c

@@ -46,6 +46,7 @@ extern int executing_builtin;
 extern void check_signals_and_traps (void);
 extern void check_signals (void);
 extern int signal_is_trapped (int);
+extern int read_builtin_timeout (int);
 
 /* Read LEN bytes from FD into BUF.  Retry the read on EINTR.  Any other
    error causes the loop to break. */
@@ -58,7 +59,8 @@ zread (fd, buf, len)
   ssize_t r;
 
   check_signals ();	/* check for signals before a blocking read */
-  while ((r = read (fd, buf, len)) < 0 && errno == EINTR)
+  while (((r = read_builtin_timeout (fd)) < 0 || (r = read (fd, buf, len)) < 0) &&
+	     errno == EINTR)
     {
       int t;
       t = errno;

quit.h

@@ -1,6 +1,6 @@
 /* quit.h -- How to handle SIGINT gracefully. */
 
-/* Copyright (C) 1993-2013 Free Software Foundation, Inc.
+/* Copyright (C) 1993-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -38,12 +38,6 @@ extern volatile sig_atomic_t terminating_signal;
     if (interrupt_state) throw_to_top_level (); \
   } while (0)
 
-#define CHECK_ALRM \
-  do { \
-    if (sigalrm_seen) \
-      sh_longjmp (alrmbuf, 1); \
-  } while (0)
-
 #define SETINTERRUPT interrupt_state = 1
 #define CLRINTERRUPT interrupt_state = 0
 

tests/case.tests

@@ -66,8 +66,6 @@ case " " in ( [" "] ) echo ok;; ( * ) echo no;; esac
 case esac in (esac) echo esac;; esac
 case k in else|done|time|esac) for f in 1 2 3 ; do :; done esac
 
-
-
 # tests of quote removal and pattern matching
 ${THIS_SH} ./case1.sub
 ${THIS_SH} ./case2.sub

tests/read.right

@@ -39,9 +39,10 @@ timeout 2: ok
 unset or null 2
 timeout 3: ok
 unset or null 3
-./read2.sub: line 43: read: -3: invalid timeout specification
+./read2.sub: line 45: read: -3: invalid timeout specification
 1
 
+abcde
 abcde
 ./read3.sub: line 17: read: -1: invalid number
 abc

tests/read2.sub

@@ -11,6 +11,8 @@
 #   You should have received a copy of the GNU General Public License
 #   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
+: ${TMPDIR:=/var/tmp}
+
 a=4
 
 read -t 1 a < /dev/tty
@@ -50,3 +52,21 @@ echo abcde | {
 	read -t 0.5 a
 	echo $a
 }
+
+read -t .0001 a <<<abcde
+echo $a
+
+# this is the original test that prompted the change to sh_timers
+cd $TMPDIR
+rm -f a.pipe
+mkfifo a.pipe
+exec 9<> a.pipe
+rm -f a.pipe
+
+for c in {0..2000}; do
+  (eval "echo {0..$c}" & read -u 9 -t 0.0001) >/dev/null
+  printf $'ok %d' "$c" >/dev/null
+done
+
+cd $OLDPWD
+rm -f $TMPDIR/a.pipe		# paranoia

tests/read7.sub

@@ -13,7 +13,7 @@
 #
 # test behavior of native readline timeouts
 
-read -t 0.001 -e var
+read -t 0.00001 -e var
 estat=$?
 if [ $estat -gt 128 ]; then
 	echo timeout 1: ok
@@ -40,7 +40,7 @@ else
 fi
 echo ${var:-unset or null 3}
 
-sleep 2 | read -t 1 -e a
+sleep 1 | read -t 0.25 -e a
 estat=$?
 if [ $estat -gt 128 ]; then
 	echo timeout 4: ok
@@ -50,6 +50,6 @@ fi
 
 # the above should all time out
 echo abcde | {
-	read -e -t 2 a
+	read -e -t 0.5 a
 	echo $a
 }

trap.c

@@ -1,7 +1,7 @@
 /* trap.c -- Not the trap command, but useful functions for manipulating
    those objects.  The trap command is in builtins/trap.def. */
 
-/* Copyright (C) 1987-2020 Free Software Foundation, Inc.
+/* Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
    This file is part of GNU Bash, the Bourne Again SHell.
 
@@ -87,7 +87,6 @@ static void reset_or_restore_signal_handlers (sh_resetsig_func_t *);
 static void trap_if_untrapped (int, char *);
 
 /* Variables used here but defined in other files. */
-extern procenv_t alrmbuf;
 
 extern volatile int from_return_trap;
 extern int waiting_for_child;
@@ -587,7 +586,8 @@ clear_pending_traps ()
 void
 check_signals ()
 {
-  CHECK_ALRM;		/* set by the read builtin */
+  /* Add any other shell timeouts here */
+  check_read_timeout ();	/* set by the read builtin */
   QUIT;
 }