[lvm-devel] master - signals: Move sigint handling out to lvm-signal.
Alasdair Kergon
agk at fedoraproject.org
Thu May 1 19:08:22 UTC 2014
Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=2eed136f0f5d9eaa65d421b2b93b6405fd7c6f08
Commit: 2eed136f0f5d9eaa65d421b2b93b6405fd7c6f08
Parent: 29a3fbf067e1685ae7e202959a414e4b13f547c7
Author: Alasdair G Kergon <agk at redhat.com>
AuthorDate: Thu May 1 20:07:17 2014 +0100
Committer: Alasdair G Kergon <agk at redhat.com>
CommitterDate: Thu May 1 20:07:17 2014 +0100
signals: Move sigint handling out to lvm-signal.
---
WHATS_NEW | 1 +
lib/cache/lvmetad.c | 1 +
lib/display/display.c | 2 +
lib/locking/locking.c | 134 +++-------------------------------------------
lib/locking/locking.h | 6 --
lib/metadata/lv_manip.c | 1 +
lib/metadata/metadata.c | 1 +
lib/misc/lvm-flock.h | 6 +-
lib/misc/lvm-signal.c | 123 +++++++++++++++++++++++++++++++++++++++++++
lib/misc/lvm-signal.h | 12 ++++-
tools/tools.h | 1 +
11 files changed, 153 insertions(+), 135 deletions(-)
diff --git a/WHATS_NEW b/WHATS_NEW
index 456f132..37225fe 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
Version 2.02.107 -
==================================
+ Separate signal handling and flock code out into lib/misc.
Don't start dmeventd checking seg_monitor and monitoring is disabled.
Catch CTRL-c during pvremove prompts.
Show correct availability status for snapshot origin in lvscan.
diff --git a/lib/cache/lvmetad.c b/lib/cache/lvmetad.c
index d0c4a4d..3470c66 100644
--- a/lib/cache/lvmetad.c
+++ b/lib/cache/lvmetad.c
@@ -21,6 +21,7 @@
#include "lvmetad-client.h"
#include "format-text.h" // TODO for disk_locn, used as a DA representation
#include "crc.h"
+#include "lvm-signal.h"
#define SCAN_TIMEOUT_SECONDS 80
#define MAX_RESCANS 10 /* Maximum number of times to scan all PVs and retry if the daemon returns a token mismatch error */
diff --git a/lib/display/display.c b/lib/display/display.c
index b83bb59..b808f25 100644
--- a/lib/display/display.c
+++ b/lib/display/display.c
@@ -20,6 +20,8 @@
#include "toolcontext.h"
#include "segtype.h"
#include "defaults.h"
+#include "lvm-signal.h"
+
#include <stdarg.h>
#define SIZE_BUF 128
diff --git a/lib/locking/locking.c b/lib/locking/locking.c
index b5250c1..673713a 100644
--- a/lib/locking/locking.c
+++ b/lib/locking/locking.c
@@ -22,148 +22,25 @@
#include "memlock.h"
#include "defaults.h"
#include "lvmcache.h"
+#include "lvm-signal.h"
#include <assert.h>
-#include <signal.h>
#include <sys/stat.h>
#include <limits.h>
#include <unistd.h>
static struct locking_type _locking;
-static sigset_t _oldset;
static int _vg_lock_count = 0; /* Number of locks held */
static int _vg_write_lock_held = 0; /* VG write lock held? */
-static int _signals_blocked = 0;
static int _blocking_supported = 0;
-static volatile sig_atomic_t _sigint_caught = 0;
-static volatile sig_atomic_t _handler_installed;
-static struct sigaction _oldhandler;
-static int _oldmasked;
-
typedef enum {
LV_NOOP,
LV_SUSPEND,
LV_RESUME
} lv_operation_t;
-static void _catch_sigint(int unused __attribute__((unused)))
-{
- _sigint_caught = 1;
-}
-
-int sigint_caught(void) {
- if (_sigint_caught)
- log_error("Interrupted...");
-
- return _sigint_caught;
-}
-
-void sigint_clear(void)
-{
- _sigint_caught = 0;
-}
-
-/*
- * Temporarily allow keyboard interrupts to be intercepted and noted;
- * saves interrupt handler state for sigint_restore(). Users should
- * use the sigint_caught() predicate to check whether interrupt was
- * requested and act appropriately. Interrupt flags are never
- * cleared automatically by this code, but the tools clear the flag
- * before running each command in lvm_run_command(). All other places
- * where the flag needs to be cleared need to call sigint_clear().
- */
-
-void sigint_allow(void)
-{
- struct sigaction handler;
- sigset_t sigs;
-
- /*
- * Do not overwrite the backed-up handler data -
- * just increase nesting count.
- */
- if (_handler_installed) {
- _handler_installed++;
- return;
- }
-
- /* Grab old sigaction for SIGINT: shall not fail. */
- sigaction(SIGINT, NULL, &handler);
- handler.sa_flags &= ~SA_RESTART; /* Clear restart flag */
- handler.sa_handler = _catch_sigint;
-
- _handler_installed = 1;
-
- /* Override the signal handler: shall not fail. */
- sigaction(SIGINT, &handler, &_oldhandler);
-
- /* Unmask SIGINT. Remember to mask it again on restore. */
- sigprocmask(0, NULL, &sigs);
- if ((_oldmasked = sigismember(&sigs, SIGINT))) {
- sigdelset(&sigs, SIGINT);
- sigprocmask(SIG_SETMASK, &sigs, NULL);
- }
-}
-
-void sigint_restore(void)
-{
- if (!_handler_installed)
- return;
-
- if (_handler_installed > 1) {
- _handler_installed--;
- return;
- }
-
- /* Nesting count went down to 0. */
- _handler_installed = 0;
-
- if (_oldmasked) {
- sigset_t sigs;
- sigprocmask(0, NULL, &sigs);
- sigaddset(&sigs, SIGINT);
- sigprocmask(SIG_SETMASK, &sigs, NULL);
- }
-
- sigaction(SIGINT, &_oldhandler, NULL);
-}
-
-static void _block_signals(uint32_t flags __attribute__((unused)))
-{
- sigset_t set;
-
- if (_signals_blocked)
- return;
-
- if (sigfillset(&set)) {
- log_sys_error("sigfillset", "_block_signals");
- return;
- }
-
- if (sigprocmask(SIG_SETMASK, &set, &_oldset)) {
- log_sys_error("sigprocmask", "_block_signals");
- return;
- }
-
- _signals_blocked = 1;
-}
-
-static void _unblock_signals(void)
-{
- /* Don't unblock signals while any locks are held */
- if (!_signals_blocked || _vg_lock_count)
- return;
-
- if (sigprocmask(SIG_SETMASK, &_oldset, NULL)) {
- log_sys_error("sigprocmask", "_block_signals");
- return;
- }
-
- _signals_blocked = 0;
-}
-
static void _lock_memory(struct cmd_context *cmd, lv_operation_t lv_op)
{
if (!(_locking.flags & LCK_PRE_MEMLOCK))
@@ -182,6 +59,13 @@ static void _unlock_memory(struct cmd_context *cmd, lv_operation_t lv_op)
critical_section_dec(cmd, "unlocking on resume");
}
+static void _unblock_signals(void)
+{
+ /* Don't unblock signals while any locks are held */
+ if (!_vg_lock_count)
+ unblock_signals();
+}
+
void reset_locking(void)
{
int was_locked = _vg_lock_count;
@@ -366,7 +250,7 @@ static int _lock_vol(struct cmd_context *cmd, const char *resource,
uint32_t lck_scope = flags & LCK_SCOPE_MASK;
int ret = 0;
- _block_signals(flags);
+ block_signals(flags);
_lock_memory(cmd, lv_op);
assert(resource);
diff --git a/lib/locking/locking.h b/lib/locking/locking.h
index aa42138..0945aa0 100644
--- a/lib/locking/locking.h
+++ b/lib/locking/locking.h
@@ -213,10 +213,4 @@ int resume_lvs(struct cmd_context *cmd, struct dm_list *lvs);
int revert_lvs(struct cmd_context *cmd, struct dm_list *lvs);
int activate_lvs(struct cmd_context *cmd, struct dm_list *lvs, unsigned exclusive);
-/* Interrupt handling */
-void sigint_clear(void);
-void sigint_allow(void);
-void sigint_restore(void);
-int sigint_caught(void);
-
#endif
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 85f7a39..6817831 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -28,6 +28,7 @@
#include "str_list.h"
#include "defaults.h"
#include "lvm-exec.h"
+#include "lvm-signal.h"
typedef enum {
PREFERRED,
diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c
index e2abba7..4791c10 100644
--- a/lib/metadata/metadata.c
+++ b/lib/metadata/metadata.c
@@ -19,6 +19,7 @@
#include "toolcontext.h"
#include "lvm-string.h"
#include "lvm-file.h"
+#include "lvm-signal.h"
#include "lvmcache.h"
#include "lvmetad.h"
#include "memlock.h"
diff --git a/lib/misc/lvm-flock.h b/lib/misc/lvm-flock.h
index 5e8aefd..3fed73e 100644
--- a/lib/misc/lvm-flock.h
+++ b/lib/misc/lvm-flock.h
@@ -12,11 +12,11 @@
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#ifndef _LVM_SIGNAL_H
-# define _LVM_SIGNAL_H
+#ifndef _LVM_FLOCK_H
+#define _LVM_FLOCK_H
void init_flock(struct cmd_context *cmd);
int lock_file(const char *file, uint32_t flags);
void release_flocks(int unlock);
-#endif /* _LVM_SIGNAL_H */
+#endif /* _LVM_FLOCK_H */
diff --git a/lib/misc/lvm-signal.c b/lib/misc/lvm-signal.c
index 927e839..f2d6d3b 100644
--- a/lib/misc/lvm-signal.c
+++ b/lib/misc/lvm-signal.c
@@ -22,6 +22,13 @@ static sig_t _oldhandler;
static sigset_t _fullsigset, _intsigset;
static volatile sig_atomic_t _handler_installed;
+static sigset_t _oldset;
+static int _signals_blocked = 0;
+static volatile sig_atomic_t _sigint_caught = 0;
+static volatile sig_atomic_t _handler_installed2;
+static struct sigaction _oldhandler2;
+static int _oldmasked;
+
void remove_ctrl_c_handler(void)
{
siginterrupt(SIGINT, 0);
@@ -54,3 +61,119 @@ void install_ctrl_c_handler(void)
sigprocmask(SIG_SETMASK, &_intsigset, NULL);
siginterrupt(SIGINT, 1);
}
+
+static void _catch_sigint(int unused __attribute__((unused)))
+{
+ _sigint_caught = 1;
+}
+
+int sigint_caught(void) {
+ if (_sigint_caught)
+ log_error("Interrupted...");
+
+ return _sigint_caught;
+}
+
+void sigint_clear(void)
+{
+ _sigint_caught = 0;
+}
+
+/*
+ * Temporarily allow keyboard interrupts to be intercepted and noted;
+ * saves interrupt handler state for sigint_restore(). Users should
+ * use the sigint_caught() predicate to check whether interrupt was
+ * requested and act appropriately. Interrupt flags are never
+ * cleared automatically by this code, but the tools clear the flag
+ * before running each command in lvm_run_command(). All other places
+ * where the flag needs to be cleared need to call sigint_clear().
+ */
+
+void sigint_allow(void)
+{
+ struct sigaction handler;
+ sigset_t sigs;
+
+ /*
+ * Do not overwrite the backed-up handler data -
+ * just increase nesting count.
+ */
+ if (_handler_installed2) {
+ _handler_installed2++;
+ return;
+ }
+
+ /* Grab old sigaction for SIGINT: shall not fail. */
+ sigaction(SIGINT, NULL, &handler);
+ handler.sa_flags &= ~SA_RESTART; /* Clear restart flag */
+ handler.sa_handler = _catch_sigint;
+
+ _handler_installed2 = 1;
+
+ /* Override the signal handler: shall not fail. */
+ sigaction(SIGINT, &handler, &_oldhandler2);
+
+ /* Unmask SIGINT. Remember to mask it again on restore. */
+ sigprocmask(0, NULL, &sigs);
+ if ((_oldmasked = sigismember(&sigs, SIGINT))) {
+ sigdelset(&sigs, SIGINT);
+ sigprocmask(SIG_SETMASK, &sigs, NULL);
+ }
+}
+
+void sigint_restore(void)
+{
+ if (!_handler_installed2)
+ return;
+
+ if (_handler_installed2 > 1) {
+ _handler_installed2--;
+ return;
+ }
+
+ /* Nesting count went down to 0. */
+ _handler_installed2 = 0;
+
+ if (_oldmasked) {
+ sigset_t sigs;
+ sigprocmask(0, NULL, &sigs);
+ sigaddset(&sigs, SIGINT);
+ sigprocmask(SIG_SETMASK, &sigs, NULL);
+ }
+
+ sigaction(SIGINT, &_oldhandler2, NULL);
+}
+
+void block_signals(uint32_t flags __attribute__((unused)))
+{
+ sigset_t set;
+
+ if (_signals_blocked)
+ return;
+
+ if (sigfillset(&set)) {
+ log_sys_error("sigfillset", "_block_signals");
+ return;
+ }
+
+ if (sigprocmask(SIG_SETMASK, &set, &_oldset)) {
+ log_sys_error("sigprocmask", "_block_signals");
+ return;
+ }
+
+ _signals_blocked = 1;
+}
+
+void unblock_signals(void)
+{
+ /* Don't unblock signals while any locks are held */
+ if (!_signals_blocked)
+ return;
+
+ if (sigprocmask(SIG_SETMASK, &_oldset, NULL)) {
+ log_sys_error("sigprocmask", "_block_signals");
+ return;
+ }
+
+ _signals_blocked = 0;
+}
diff --git a/lib/misc/lvm-signal.h b/lib/misc/lvm-signal.h
index ce9d2e9..f2e6141 100644
--- a/lib/misc/lvm-signal.h
+++ b/lib/misc/lvm-signal.h
@@ -14,7 +14,17 @@
*/
#ifndef _LVM_SIGNAL_H
-# define _LVM_SIGNAL_H
+#define _LVM_SIGNAL_H
+
void remove_ctrl_c_handler(void);
void install_ctrl_c_handler(void);
+
+void sigint_allow(void);
+int sigint_caught(void);
+void sigint_restore(void);
+void sigint_clear(void);
+
+void block_signals(uint32_t flags);
+void unblock_signals(void);
+
#endif
diff --git a/tools/tools.h b/tools/tools.h
index a2bfe0d..11111cb 100644
--- a/tools/tools.h
+++ b/tools/tools.h
@@ -40,6 +40,7 @@
#include "locking.h"
#include "lvm-exec.h"
#include "lvm-file.h"
+#include "lvm-signal.h"
#include "lvm-string.h"
#include "segtype.h"
#include "str_list.h"
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