void critical_section_dec(struct cmd_context *cmd, const char *reason)
{
if (_critical_section && !dm_get_suspended_counter()) {
_critical_section = 0;
log_debug_mem("Leaving critical section (%s).", reason);
}
}
void memlock_reset(void)
{
log_debug_mem("memlock reset.");
_mem_locked = 0;
_critical_section = 0;
_memlock_count_daemon = 0;
}
static void _unlock_mem(struct cmd_context *cmd)
{
size_t unlock_mstats;
log_very_verbose("Unlocking memory");
if (!_memlock_maps(cmd, LVM_MUNLOCK, &unlock_mstats))
stack;
if (!_use_mlockall) {
_restore_mmap();
if (close(_maps_fd))
log_sys_error("close", _procselfmaps);
dm_free(_maps_buffer);
_maps_buffer = NULL;
if (_mstats < unlock_mstats) {
if ((_mstats + lvm_getpagesize()) < unlock_mstats)
log_error(INTERNAL_ERROR
"Reserved memory (%ld) not enough: used %ld. Increase activation/reserved_memory?",
(long)_mstats, (long)unlock_mstats);
else
/* FIXME Believed due to incorrect use of yes_no_prompt while locks held */
log_debug_mem("Suppressed internal error: Maps lock %ld < unlock %ld, a one-page difference.",
(long)_mstats, (long)unlock_mstats);
}
}
if (setpriority(PRIO_PROCESS, 0, _priority))
log_error("setpriority %u failed: %s", _priority,
strerror(errno));
_release_memory();
}
void memlock_inc_daemon(struct cmd_context *cmd)
{
++_memlock_count_daemon;
if (_memlock_count_daemon == 1 && _critical_section > 0)
log_error(INTERNAL_ERROR "_memlock_inc_daemon used in critical section.");
log_debug_mem("memlock_count_daemon inc to %d", _memlock_count_daemon);
_lock_mem_if_needed(cmd);
}
static int _disable_mmap(void)
{
#ifdef ARCH_X86
volatile unsigned char *abs_addr;
if (!_mmap_addr) {
_mmap_addr = (unsigned char *) dlsym(RTLD_NEXT, "mmap");
if (_mmap_addr[0] == 0xff && _mmap_addr[1] == 0x25) { /* plt */
#ifdef __x86_64__
abs_addr = _mmap_addr + 6 + *(int32_t *)(_mmap_addr + 2);
#endif /* __x86_64__ */
#ifdef __i386__
abs_addr = *(void **)(_mmap_addr + 2);
#endif /* __i386__ */
_mmap_addr = *(void **)abs_addr;
} else
log_debug_mem("Can't find PLT jump entry assuming -fPIE linkage.");
if (mprotect((void *)((unsigned long)_mmap_addr & ~4095UL), 4096, PROT_READ|PROT_WRITE|PROT_EXEC)) {
log_sys_error("mprotect", "");
_mmap_addr = NULL;
return 0;
}
_mmap_orig = *_mmap_addr;
}
log_debug_mem("Remapping mmap entry %02x to %02x.", _mmap_orig, INSTRUCTION_HLT);
*_mmap_addr = INSTRUCTION_HLT;
#ifdef __i386__
if (!_mmap64_addr) {
_mmap64_addr = (unsigned char *) dlsym(RTLD_NEXT, "mmap64");
if (_mmap64_addr[0] == 0xff && _mmap64_addr[1] == 0x25) {
abs_addr = *(void **)(_mmap64_addr + 2);
_mmap64_addr = *(void **)abs_addr;
} /* Can't find PLT jump entry assuming -fPIE linkage */
if (mprotect((void *)((unsigned long)_mmap64_addr & ~4095UL), 4096, PROT_READ|PROT_WRITE|PROT_EXEC)) {
log_sys_error("mprotect", "");
_mmap64_addr = NULL;
return 0;
}
_mmap64_orig = *_mmap64_addr;
}
*_mmap64_addr = INSTRUCTION_HLT;
#endif /* __i386__ */
#endif /* ARCH_X86 */
return 1;
}
void memlock_dec_daemon(struct cmd_context *cmd)
{
if (!_memlock_count_daemon)
log_error(INTERNAL_ERROR "_memlock_count_daemon has dropped below 0.");
--_memlock_count_daemon;
log_debug_mem("memlock_count_daemon dec to %d", _memlock_count_daemon);
_unlock_mem_if_possible(cmd);
}
static void _lock_mem_if_needed(struct cmd_context *cmd)
{
log_debug_mem("Lock: Memlock counters: locked:%d critical:%d daemon:%d suspended:%d",
_mem_locked, _critical_section, _memlock_count_daemon, dm_get_suspended_counter());
if (!_mem_locked &&
((_critical_section + _memlock_count_daemon) == 1)) {
_mem_locked = 1;
_lock_mem(cmd);
}
}
static void _unlock_mem_if_possible(struct cmd_context *cmd)
{
log_debug_mem("Unlock: Memlock counters: locked:%d critical:%d daemon:%d suspended:%d",
_mem_locked, _critical_section, _memlock_count_daemon, dm_get_suspended_counter());
if (_mem_locked &&
!_critical_section &&
!_memlock_count_daemon) {
_unlock_mem(cmd);
_mem_locked = 0;
}
}
void memlock_dec_daemon(struct cmd_context *cmd)
{
if (!_memlock_count_daemon)
log_error(INTERNAL_ERROR "_memlock_count_daemon has dropped below 0.");
--_memlock_count_daemon;
log_debug_mem("memlock_count_daemon dec to %d", _memlock_count_daemon);
if (!_memlock_count_daemon && _critical_section && _mem_locked) {
log_error("Unlocking daemon memory in critical section.");
_unlock_mem(cmd);
_mem_locked = 0;
}
_unlock_mem_if_possible(cmd);
}
static int _restore_mmap(void)
{
#ifdef ARCH_X86
if (_mmap_addr)
*_mmap_addr = _mmap_orig;
#ifdef __i386__
if (_mmap64_addr)
*_mmap64_addr = _mmap64_orig;
#endif /* __i386__ */
log_debug_mem("Restored mmap entry.");
#endif /* ARCH_X86 */
return 1;
}
void critical_section_inc(struct cmd_context *cmd, const char *reason)
{
/*
* Profiles are loaded on-demand so make sure that before
* entering the critical section all needed profiles are
* loaded to avoid the disk access later.
*/
(void) load_pending_profiles(cmd);
if (!_critical_section) {
_critical_section = 1;
log_debug_mem("Entering critical section (%s).", reason);
}
_lock_mem_if_needed(cmd);
}
static int _memlock_maps(struct cmd_context *cmd, lvmlock_t lock, size_t *mstats)
{
const struct dm_config_node *cn;
char *line, *line_end;
size_t len;
ssize_t n;
int ret = 1;
if (_use_mlockall) {
#ifdef MCL_CURRENT
if (lock == LVM_MLOCK) {
if (mlockall(MCL_CURRENT | MCL_FUTURE)) {
log_sys_error("mlockall", "");
return 0;
}
} else {
if (munlockall()) {
log_sys_error("munlockall", "");
return 0;
}
}
return 1;
#else
return 0;
#endif
}
/* Reset statistic counters */
*mstats = 0;
/* read mapping into a single memory chunk without reallocation
* in the middle of reading maps file */
for (len = 0;;) {
if (!_maps_buffer || len >= _maps_len) {
if (_maps_buffer)
_maps_len *= 2;
if (!(line = dm_realloc(_maps_buffer, _maps_len))) {
log_error("Allocation of maps buffer failed.");
return 0;
}
_maps_buffer = line;
}
if (lseek(_maps_fd, 0, SEEK_SET))
log_sys_error("lseek", _procselfmaps);
for (len = 0 ; len < _maps_len; len += n) {
if (!(n = read(_maps_fd, _maps_buffer + len, _maps_len - len)))
break; /* EOF */
if (n == -1) {
log_sys_error("read", _procselfmaps);
return 0;
}
}
if (len < _maps_len) { /* fits in buffer */
_maps_buffer[len] = '\0';
break;
}
}
line = _maps_buffer;
cn = find_config_tree_array(cmd, activation_mlock_filter_CFG, NULL);
while ((line_end = strchr(line, '\n'))) {
*line_end = '\0'; /* remove \n */
if (!_maps_line(cn, lock, line, mstats))
ret = 0;
line = line_end + 1;
}
log_debug_mem("%socked %ld bytes",
(lock == LVM_MLOCK) ? "L" : "Unl", (long)*mstats);
return ret;
}
/*
* mlock/munlock memory areas from /proc/self/maps
* format described in kernel/Documentation/filesystem/proc.txt
*/
static int _maps_line(const struct dm_config_node *cn, lvmlock_t lock,
const char *line, size_t *mstats)
{
const struct dm_config_value *cv;
long from, to;
int pos;
unsigned i;
char fr, fw, fx, fp;
size_t sz;
const char *lock_str = (lock == LVM_MLOCK) ? "mlock" : "munlock";
if (sscanf(line, "%lx-%lx %c%c%c%c%n",
&from, &to, &fr, &fw, &fx, &fp, &pos) != 6) {
log_error("Failed to parse maps line: %s", line);
return 0;
}
/* Select readable maps */
if (fr != 'r') {
log_debug_mem("%s area unreadable %s : Skipping.", lock_str, line);
return 1;
}
/* always ignored areas */
for (i = 0; i < DM_ARRAY_SIZE(_ignore_maps); ++i)
if (strstr(line + pos, _ignore_maps[i])) {
log_debug_mem("%s ignore filter '%s' matches '%s': Skipping.",
lock_str, _ignore_maps[i], line);
return 1;
}
sz = to - from;
if (!cn) {
/* If no blacklist configured, use an internal set */
for (i = 0; i < DM_ARRAY_SIZE(_blacklist_maps); ++i)
if (strstr(line + pos, _blacklist_maps[i])) {
log_debug_mem("%s default filter '%s' matches '%s': Skipping.",
lock_str, _blacklist_maps[i], line);
return 1;
}
} else {
for (cv = cn->v; cv; cv = cv->next) {
if ((cv->type != DM_CFG_STRING) || !cv->v.str[0])
continue;
if (strstr(line + pos, cv->v.str)) {
log_debug_mem("%s_filter '%s' matches '%s': Skipping.",
lock_str, cv->v.str, line);
return 1;
}
}
}
#ifdef HAVE_VALGRIND
/*
* Valgrind is continually eating memory while executing code
* so we need to deactivate check of locked memory size
*/
#ifndef VALGRIND_POOL
if (RUNNING_ON_VALGRIND)
#endif
sz -= sz; /* = 0, but avoids getting warning about dead assigment */
#endif
*mstats += sz;
log_debug_mem("%s %10ldKiB %12lx - %12lx %c%c%c%c%s", lock_str,
((long)sz + 1023) / 1024, from, to, fr, fw, fx, fp, line + pos);
if (lock == LVM_MLOCK) {
if (mlock((const void*)from, sz) < 0) {
log_sys_error("mlock", line);
return 0;
}
} else {
if (munlock((const void*)from, sz) < 0) {
log_sys_error("munlock", line);
return 0;
}
}
return 1;
}
