D7: editor multi-cursor support
Add secondary_cursors field to Editor with insert_char_multi, delete_back_multi, delete_forward_multi methods. Right-to-left processing ensures position shifts don't corrupt earlier insertions. 7 new tests: add/clear, all_positions, insert, delete_back, delete_forward, unicode, duplicate-add.
This commit is contained in:
@@ -0,0 +1,329 @@
|
||||
/* Stack overflow handling.
|
||||
|
||||
Copyright (C) 2002, 2004, 2006, 2008-2017 Free Software Foundation, Inc.
|
||||
|
||||
This program 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.
|
||||
|
||||
This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
|
||||
|
||||
/* Written by Paul Eggert. */
|
||||
|
||||
/* NOTES:
|
||||
|
||||
A program that uses alloca, dynamic arrays, or large local
|
||||
variables may extend the stack by more than a page at a time. If
|
||||
so, when the stack overflows the operating system may not detect
|
||||
the overflow until the program uses the array, and this module may
|
||||
incorrectly report a program error instead of a stack overflow.
|
||||
|
||||
To avoid this problem, allocate only small objects on the stack; a
|
||||
program should be OK if it limits single allocations to a page or
|
||||
less. Allocate larger arrays in static storage, or on the heap
|
||||
(e.g., with malloc). Yes, this is a pain, but we don't know of any
|
||||
better solution that is portable.
|
||||
|
||||
No attempt has been made to deal with multithreaded applications. */
|
||||
|
||||
#include <config.h>
|
||||
|
||||
#ifndef __attribute__
|
||||
# if __GNUC__ < 3
|
||||
# define __attribute__(x)
|
||||
# endif
|
||||
#endif
|
||||
|
||||
#include "gettext.h"
|
||||
#define _(msgid) gettext (msgid)
|
||||
|
||||
#include <errno.h>
|
||||
|
||||
#include <signal.h>
|
||||
#if ! HAVE_STACK_T && ! defined stack_t
|
||||
typedef struct sigaltstack stack_t;
|
||||
#endif
|
||||
#ifndef SIGSTKSZ
|
||||
# define SIGSTKSZ 16384
|
||||
#elif HAVE_LIBSIGSEGV && SIGSTKSZ < 16384
|
||||
/* libsigsegv 2.6 through 2.8 have a bug where some architectures use
|
||||
more than the Linux default of an 8k alternate stack when deciding
|
||||
if a fault was caused by stack overflow. */
|
||||
# undef SIGSTKSZ
|
||||
# define SIGSTKSZ 16384
|
||||
#endif
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
/* Posix 2001 declares ucontext_t in <ucontext.h>, Posix 200x in
|
||||
<signal.h>. */
|
||||
#if HAVE_UCONTEXT_H
|
||||
# include <ucontext.h>
|
||||
#endif
|
||||
|
||||
#include <unistd.h>
|
||||
|
||||
#if HAVE_LIBSIGSEGV
|
||||
# include <sigsegv.h>
|
||||
#endif
|
||||
|
||||
#include "c-stack.h"
|
||||
#include "exitfail.h"
|
||||
#include "ignore-value.h"
|
||||
#include "getprogname.h"
|
||||
|
||||
#if defined SA_ONSTACK && defined SA_SIGINFO
|
||||
# define SIGINFO_WORKS 1
|
||||
#else
|
||||
# define SIGINFO_WORKS 0
|
||||
# ifndef SA_ONSTACK
|
||||
# define SA_ONSTACK 0
|
||||
# endif
|
||||
#endif
|
||||
|
||||
/* The user-specified action to take when a SEGV-related program error
|
||||
or stack overflow occurs. */
|
||||
static void (* volatile segv_action) (int);
|
||||
|
||||
/* Translated messages for program errors and stack overflow. Do not
|
||||
translate them in the signal handler, since gettext is not
|
||||
async-signal-safe. */
|
||||
static char const * volatile program_error_message;
|
||||
static char const * volatile stack_overflow_message;
|
||||
|
||||
/* Output an error message, then exit with status EXIT_FAILURE if it
|
||||
appears to have been a stack overflow, or with a core dump
|
||||
otherwise. This function is async-signal-safe. */
|
||||
|
||||
static _Noreturn void
|
||||
die (int signo)
|
||||
{
|
||||
char const *message;
|
||||
#if !SIGINFO_WORKS && !HAVE_LIBSIGSEGV
|
||||
/* We can't easily determine whether it is a stack overflow; so
|
||||
assume that the rest of our program is perfect (!) and that
|
||||
this segmentation violation is a stack overflow. */
|
||||
signo = 0;
|
||||
#endif /* !SIGINFO_WORKS && !HAVE_LIBSIGSEGV */
|
||||
segv_action (signo);
|
||||
message = signo ? program_error_message : stack_overflow_message;
|
||||
ignore_value (write (STDERR_FILENO, getprogname (), strlen (getprogname ())));
|
||||
ignore_value (write (STDERR_FILENO, ": ", 2));
|
||||
ignore_value (write (STDERR_FILENO, message, strlen (message)));
|
||||
ignore_value (write (STDERR_FILENO, "\n", 1));
|
||||
if (! signo)
|
||||
_exit (exit_failure);
|
||||
raise (signo);
|
||||
abort ();
|
||||
}
|
||||
|
||||
#if (HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK \
|
||||
&& HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV
|
||||
|
||||
/* Storage for the alternate signal stack. */
|
||||
static union
|
||||
{
|
||||
char buffer[SIGSTKSZ];
|
||||
|
||||
/* These other members are for proper alignment. There's no
|
||||
standard way to guarantee stack alignment, but this seems enough
|
||||
in practice. */
|
||||
long double ld;
|
||||
long l;
|
||||
void *p;
|
||||
} alternate_signal_stack;
|
||||
|
||||
static void
|
||||
null_action (int signo __attribute__ ((unused)))
|
||||
{
|
||||
}
|
||||
|
||||
#endif /* SIGALTSTACK || LIBSIGSEGV */
|
||||
|
||||
/* Only use libsigsegv if we need it; platforms like Solaris can
|
||||
detect stack overflow without the overhead of an external
|
||||
library. */
|
||||
#if HAVE_LIBSIGSEGV && ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC
|
||||
|
||||
/* Nonzero if general segv handler could not be installed. */
|
||||
static volatile int segv_handler_missing;
|
||||
|
||||
/* Handle a segmentation violation and exit if it cannot be stack
|
||||
overflow. This function is async-signal-safe. */
|
||||
|
||||
static int segv_handler (void *address __attribute__ ((unused)),
|
||||
int serious)
|
||||
{
|
||||
# if DEBUG
|
||||
{
|
||||
char buf[1024];
|
||||
sprintf (buf, "segv_handler serious=%d\n", serious);
|
||||
write (STDERR_FILENO, buf, strlen (buf));
|
||||
}
|
||||
# endif
|
||||
|
||||
/* If this fault is not serious, return 0 to let the stack overflow
|
||||
handler take a shot at it. */
|
||||
if (!serious)
|
||||
return 0;
|
||||
die (SIGSEGV);
|
||||
}
|
||||
|
||||
/* Handle a segmentation violation that is likely to be a stack
|
||||
overflow and exit. This function is async-signal-safe. */
|
||||
|
||||
static _Noreturn void
|
||||
overflow_handler (int emergency,
|
||||
stackoverflow_context_t context __attribute__ ((unused)))
|
||||
{
|
||||
# if DEBUG
|
||||
{
|
||||
char buf[1024];
|
||||
sprintf (buf, "overflow_handler emergency=%d segv_handler_missing=%d\n",
|
||||
emergency, segv_handler_missing);
|
||||
write (STDERR_FILENO, buf, strlen (buf));
|
||||
}
|
||||
# endif
|
||||
|
||||
die ((!emergency || segv_handler_missing) ? 0 : SIGSEGV);
|
||||
}
|
||||
|
||||
int
|
||||
c_stack_action (void (*action) (int))
|
||||
{
|
||||
segv_action = action ? action : null_action;
|
||||
program_error_message = _("program error");
|
||||
stack_overflow_message = _("stack overflow");
|
||||
|
||||
/* Always install the overflow handler. */
|
||||
if (stackoverflow_install_handler (overflow_handler,
|
||||
alternate_signal_stack.buffer,
|
||||
sizeof alternate_signal_stack.buffer))
|
||||
{
|
||||
errno = ENOTSUP;
|
||||
return -1;
|
||||
}
|
||||
/* Try installing a general handler; if it fails, then treat all
|
||||
segv as stack overflow. */
|
||||
segv_handler_missing = sigsegv_install_handler (segv_handler);
|
||||
return 0;
|
||||
}
|
||||
|
||||
#elif HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING
|
||||
|
||||
# if SIGINFO_WORKS
|
||||
|
||||
/* Handle a segmentation violation and exit. This function is
|
||||
async-signal-safe. */
|
||||
|
||||
static _Noreturn void
|
||||
segv_handler (int signo, siginfo_t *info,
|
||||
void *context __attribute__ ((unused)))
|
||||
{
|
||||
/* Clear SIGNO if it seems to have been a stack overflow. */
|
||||
# if ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC
|
||||
/* We can't easily determine whether it is a stack overflow; so
|
||||
assume that the rest of our program is perfect (!) and that
|
||||
this segmentation violation is a stack overflow.
|
||||
|
||||
Note that although both Linux and Solaris provide
|
||||
sigaltstack, SA_ONSTACK, and SA_SIGINFO, currently only
|
||||
Solaris satisfies the XSI heuristic. This is because
|
||||
Solaris populates uc_stack with the details of the
|
||||
interrupted stack, while Linux populates it with the details
|
||||
of the current stack. */
|
||||
signo = 0;
|
||||
# else
|
||||
if (0 < info->si_code)
|
||||
{
|
||||
/* If the faulting address is within the stack, or within one
|
||||
page of the stack, assume that it is a stack overflow. */
|
||||
ucontext_t const *user_context = context;
|
||||
char const *stack_base = user_context->uc_stack.ss_sp;
|
||||
size_t stack_size = user_context->uc_stack.ss_size;
|
||||
char const *faulting_address = info->si_addr;
|
||||
size_t page_size = sysconf (_SC_PAGESIZE);
|
||||
size_t s = faulting_address - stack_base + page_size;
|
||||
if (s < stack_size + 2 * page_size)
|
||||
signo = 0;
|
||||
|
||||
# if DEBUG
|
||||
{
|
||||
char buf[1024];
|
||||
sprintf (buf,
|
||||
"segv_handler fault=%p base=%p size=%lx page=%lx signo=%d\n",
|
||||
faulting_address, stack_base, (unsigned long) stack_size,
|
||||
(unsigned long) page_size, signo);
|
||||
write (STDERR_FILENO, buf, strlen (buf));
|
||||
}
|
||||
# endif
|
||||
}
|
||||
# endif
|
||||
|
||||
die (signo);
|
||||
}
|
||||
# endif
|
||||
|
||||
int
|
||||
c_stack_action (void (*action) (int))
|
||||
{
|
||||
int r;
|
||||
stack_t st;
|
||||
struct sigaction act;
|
||||
st.ss_flags = 0;
|
||||
# if SIGALTSTACK_SS_REVERSED
|
||||
/* Irix mistakenly treats ss_sp as the upper bound, rather than
|
||||
lower bound, of the alternate stack. */
|
||||
st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ - sizeof (void *);
|
||||
st.ss_size = sizeof alternate_signal_stack.buffer - sizeof (void *);
|
||||
# else
|
||||
st.ss_sp = alternate_signal_stack.buffer;
|
||||
st.ss_size = sizeof alternate_signal_stack.buffer;
|
||||
# endif
|
||||
r = sigaltstack (&st, NULL);
|
||||
if (r != 0)
|
||||
return r;
|
||||
|
||||
segv_action = action ? action : null_action;
|
||||
program_error_message = _("program error");
|
||||
stack_overflow_message = _("stack overflow");
|
||||
|
||||
sigemptyset (&act.sa_mask);
|
||||
|
||||
# if SIGINFO_WORKS
|
||||
/* POSIX 1003.1-2001 says SA_RESETHAND implies SA_NODEFER, but
|
||||
this is not true on Solaris 8 at least. It doesn't hurt to use
|
||||
SA_NODEFER here, so leave it in. */
|
||||
act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
|
||||
act.sa_sigaction = segv_handler;
|
||||
# else
|
||||
act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
|
||||
act.sa_handler = die;
|
||||
# endif
|
||||
|
||||
# if FAULT_YIELDS_SIGBUS
|
||||
if (sigaction (SIGBUS, &act, NULL) < 0)
|
||||
return -1;
|
||||
# endif
|
||||
return sigaction (SIGSEGV, &act, NULL);
|
||||
}
|
||||
|
||||
#else /* ! ((HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK
|
||||
&& HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV) */
|
||||
|
||||
int
|
||||
c_stack_action (void (*action) (int) __attribute__ ((unused)))
|
||||
{
|
||||
errno = ENOTSUP;
|
||||
return -1;
|
||||
}
|
||||
|
||||
#endif
|
||||
Reference in New Issue
Block a user