Fix bug where tdb lock call interrupted with

an alarm sig would not terminate and could lead
to runaway smbd processes.
Thanks to Dave Daugherty @ Centrify for pointing
this out to us.
Jeremy.
(This used to be commit ef8da1698371c95495add53df81a978df709c88d)

9 files changed, 29 insertions, 0 deletions

diff --git a/source3/lib/replace/replace.h b/source3/lib/replace/replace.h
index e42d5ff168..55ed2e9570 100644
--- a/source3/lib/replace/replace.h
+++ b/source3/lib/replace/replace.h
@@ -452,6 +452,10 @@ typedef int bool;
 #define MAX(a,b) ((a)>(b)?(a):(b))
 #endif
 
+#if !defined(HAVE_VOLATILE)
+#define volatile
+#endif
+
 /**
   this is a warning hack. The idea is to use this everywhere that we
   get the "discarding const" warning from gcc. That doesn't actually
diff --git a/source3/lib/replace/system/wait.h b/source3/lib/replace/system/wait.h
index de94cf09d5..5784b1ae92 100644
--- a/source3/lib/replace/system/wait.h
+++ b/source3/lib/replace/system/wait.h
@@ -48,4 +48,8 @@
 #define SA_RESETHAND SA_ONESHOT
 #endif
 
+#if !defined(HAVE_SIG_ATOMIC_T_TYPE)
+typedef int sig_atomic_t;
+#endif
+
 #endif
diff --git a/source3/lib/tdb/common/lock.c b/source3/lib/tdb/common/lock.c
index 22896f5227..43be5d20e1 100644
--- a/source3/lib/tdb/common/lock.c
+++ b/source3/lib/tdb/common/lock.c
@@ -27,6 +27,11 @@
 
 #include "tdb_private.h"
 
+void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
+{
+	tdb->interrupt_sig_ptr = ptr;
+}
+
 /* a byte range locking function - return 0 on success
    this functions locks/unlocks 1 byte at the specified offset.
 
@@ -58,6 +63,13 @@ int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset,
 
 	do {
 		ret = fcntl(tdb->fd,lck_type,&fl);
+
+		/* Check for a sigalarm break. */
+		if (ret == -1 && errno == EINTR &&
+				tdb->interrupt_sig_ptr &&
+				*tdb->interrupt_sig_ptr) {
+			break;
+		}
 	} while (ret == -1 && errno == EINTR);
 
 	if (ret == -1) {
diff --git a/source3/lib/tdb/common/tdb_private.h b/source3/lib/tdb/common/tdb_private.h
index d2f2c23d72..daef07aff1 100644
--- a/source3/lib/tdb/common/tdb_private.h
+++ b/source3/lib/tdb/common/tdb_private.h
@@ -28,6 +28,7 @@
 #include "system/time.h"
 #include "system/shmem.h"
 #include "system/select.h"
+#include "system/wait.h"
 #include "tdb.h"
 
 #ifndef HAVE_GETPAGESIZE
@@ -161,6 +162,7 @@ struct tdb_context {
 	struct tdb_transaction *transaction;
 	int page_size;
 	int max_dead_records;
+	volatile sig_atomic_t *interrupt_sig_ptr;
 };
 
 
diff --git a/source3/lib/tdb/include/tdb.h b/source3/lib/tdb/include/tdb.h
index a75df2d7d5..21410e840b 100644
--- a/source3/lib/tdb/include/tdb.h
+++ b/source3/lib/tdb/include/tdb.h
@@ -138,6 +138,8 @@ int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
 int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
 int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
 
+void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *sigptr);
+
 /* Debug functions. Not used in production. */
 void tdb_dump_all(struct tdb_context *tdb);
 int tdb_printfreelist(struct tdb_context *tdb);
diff --git a/source3/lib/tdb/tools/tdbbackup.c b/source3/lib/tdb/tools/tdbbackup.c
index dedfb9e665..6f3ca48314 100644
--- a/source3/lib/tdb/tools/tdbbackup.c
+++ b/source3/lib/tdb/tools/tdbbackup.c
@@ -44,6 +44,7 @@
 #include "system/locale.h"
 #include "system/time.h"
 #include "system/filesys.h"
+#include "system/wait.h"
 #include "tdb.h"
 
 #ifdef HAVE_GETOPT_H
diff --git a/source3/lib/tdb/tools/tdbdump.c b/source3/lib/tdb/tools/tdbdump.c
index a654c0fb31..8d930383b0 100644
--- a/source3/lib/tdb/tools/tdbdump.c
+++ b/source3/lib/tdb/tools/tdbdump.c
@@ -21,6 +21,7 @@
 #include "system/locale.h"
 #include "system/time.h"
 #include "system/filesys.h"
+#include "system/wait.h"
 #include "tdb.h"
 
 static void print_data(TDB_DATA d)
diff --git a/source3/lib/tdb/tools/tdbtool.c b/source3/lib/tdb/tools/tdbtool.c
index da040f95f3..79435a3571 100644
--- a/source3/lib/tdb/tools/tdbtool.c
+++ b/source3/lib/tdb/tools/tdbtool.c
@@ -24,6 +24,7 @@
 #include "system/locale.h"
 #include "system/time.h"
 #include "system/filesys.h"
+#include "system/wait.h"
 #include "tdb.h"
 
 static int do_command(void);
diff --git a/source3/lib/util_tdb.c b/source3/lib/util_tdb.c
index 6aa7a5348f..35c1a92ad5 100644
--- a/source3/lib/util_tdb.c
+++ b/source3/lib/util_tdb.c
@@ -72,6 +72,7 @@ static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key,
 
 	if (timeout) {
 		CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
+		tdb_setalarm_sigptr(tdb, &gotalarm);
 		alarm(timeout);
 	}
 
@@ -82,6 +83,7 @@ static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key,
 
 	if (timeout) {
 		alarm(0);
+		tdb_setalarm_sigptr(tdb, NULL);
 		CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
 		if (gotalarm) {
 			DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",