diff options
author | Kay Sievers <kay@vrfy.org> | 2015-06-09 14:27:33 +0200 |
---|---|---|
committer | Kay Sievers <kay@vrfy.org> | 2015-06-11 10:52:46 +0200 |
commit | a095315b3c31f7a419baceac82c26c3c5ac0cd12 (patch) | |
tree | a5a70cf5b5430c0a6873311437b8345d7071f249 /src/shared/sigbus.c | |
parent | 37c47e5e5b8e47dd886ed6e8355b1203082b4a3e (diff) |
build-sys: split internal basic/ library from shared/
basic/ can be used by everything
cannot use anything outside of basic/
libsystemd/ can use basic/
cannot use shared/
shared/ can use libsystemd/
Diffstat (limited to 'src/shared/sigbus.c')
-rw-r--r-- | src/shared/sigbus.c | 152 |
1 files changed, 0 insertions, 152 deletions
diff --git a/src/shared/sigbus.c b/src/shared/sigbus.c deleted file mode 100644 index 0108603fe8..0000000000 --- a/src/shared/sigbus.c +++ /dev/null @@ -1,152 +0,0 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - -/*** - This file is part of systemd. - - Copyright 2014 Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <signal.h> -#include <sys/mman.h> - -#include "macro.h" -#include "util.h" -#include "sigbus.h" - -#define SIGBUS_QUEUE_MAX 64 - -static struct sigaction old_sigaction; -static unsigned n_installed = 0; - -/* We maintain a fixed size list of page addresses that triggered a - SIGBUS. We access with list with atomic operations, so that we - don't have to deal with locks between signal handler and main - programs in possibly multiple threads. */ - -static void* volatile sigbus_queue[SIGBUS_QUEUE_MAX]; -static volatile sig_atomic_t n_sigbus_queue = 0; - -static void sigbus_push(void *addr) { - unsigned u; - - assert(addr); - - /* Find a free place, increase the number of entries and leave, if we can */ - for (u = 0; u < SIGBUS_QUEUE_MAX; u++) - if (__sync_bool_compare_and_swap(&sigbus_queue[u], NULL, addr)) { - __sync_fetch_and_add(&n_sigbus_queue, 1); - return; - } - - /* If we can't, make sure the queue size is out of bounds, to - * mark it as overflow */ - for (;;) { - unsigned c; - - __sync_synchronize(); - c = n_sigbus_queue; - - if (c > SIGBUS_QUEUE_MAX) /* already overflow */ - return; - - if (__sync_bool_compare_and_swap(&n_sigbus_queue, c, c + SIGBUS_QUEUE_MAX)) - return; - } -} - -int sigbus_pop(void **ret) { - assert(ret); - - for (;;) { - unsigned u, c; - - __sync_synchronize(); - c = n_sigbus_queue; - - if (_likely_(c == 0)) - return 0; - - if (_unlikely_(c >= SIGBUS_QUEUE_MAX)) - return -EOVERFLOW; - - for (u = 0; u < SIGBUS_QUEUE_MAX; u++) { - void *addr; - - addr = sigbus_queue[u]; - if (!addr) - continue; - - if (__sync_bool_compare_and_swap(&sigbus_queue[u], addr, NULL)) { - __sync_fetch_and_sub(&n_sigbus_queue, 1); - *ret = addr; - return 1; - } - } - } -} - -static void sigbus_handler(int sn, siginfo_t *si, void *data) { - unsigned long ul; - void *aligned; - - assert(sn == SIGBUS); - assert(si); - - if (si->si_code != BUS_ADRERR || !si->si_addr) { - assert_se(sigaction(SIGBUS, &old_sigaction, NULL) == 0); - raise(SIGBUS); - return; - } - - ul = (unsigned long) si->si_addr; - ul = ul / page_size(); - ul = ul * page_size(); - aligned = (void*) ul; - - /* Let's remember which address failed */ - sigbus_push(aligned); - - /* Replace mapping with an anonymous page, so that the - * execution can continue, however with a zeroed out page */ - assert_se(mmap(aligned, page_size(), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0) == aligned); -} - -void sigbus_install(void) { - struct sigaction sa = { - .sa_sigaction = sigbus_handler, - .sa_flags = SA_SIGINFO, - }; - - n_installed++; - - if (n_installed == 1) - assert_se(sigaction(SIGBUS, &sa, &old_sigaction) == 0); - - return; -} - -void sigbus_reset(void) { - - if (n_installed <= 0) - return; - - n_installed--; - - if (n_installed == 0) - assert_se(sigaction(SIGBUS, &old_sigaction, NULL) == 0); - - return; -} |