[pacman-dev] [PATCH] make alpm_unlock and trans_interrupt async safe

[Andrew Gregory]

RET_ERR calls _alpm_log which includes calls that are not safe for use
in asynchronous signal handlers (see signal(7)).  Replace it in
functions called from our signal handlers with a new macro RET_ERR_ASYNC
which is identical except that it lacks the call to _alpm_log.

Signed-off-by: Andrew Gregory <andrew.gregory.8 at gmail.com>
---
 lib/libalpm/handle.c | 2 +-
 lib/libalpm/trans.c  | 8 +++++---
 lib/libalpm/util.h   | 4 ++++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/libalpm/handle.c b/lib/libalpm/handle.c
index e4bde1a..578647e 100644
--- a/lib/libalpm/handle.c
+++ b/lib/libalpm/handle.c
@@ -141,7 +141,7 @@ int SYMEXPORT alpm_unlock(alpm_handle_t *handle)
 	handle->lockfd = -1;
 
 	if(unlink(handle->lockfile) != 0) {
-		RET_ERR(handle, ALPM_ERR_SYSTEM, -1);
+		RET_ERR_ASYNC(handle, ALPM_ERR_SYSTEM, -1);
 	} else {
 		return 0;
 	}
diff --git a/lib/libalpm/trans.c b/lib/libalpm/trans.c
index 239d6a1..30b288a 100644
--- a/lib/libalpm/trans.c
+++ b/lib/libalpm/trans.c
@@ -233,7 +233,9 @@ int SYMEXPORT alpm_trans_commit(alpm_handle_t *handle, alpm_list_t **data)
 	return 0;
 }
 
-/** Interrupt a transaction. */
+/** Interrupt a transaction.
+ * @note Safe to call from inside signal handlers.
+ */
 int SYMEXPORT alpm_trans_interrupt(alpm_handle_t *handle)
 {
 	alpm_trans_t *trans;
@@ -242,9 +244,9 @@ int SYMEXPORT alpm_trans_interrupt(alpm_handle_t *handle)
 	CHECK_HANDLE(handle, return -1);
 
 	trans = handle->trans;
-	ASSERT(trans != NULL, RET_ERR(handle, ALPM_ERR_TRANS_NULL, -1));
+	ASSERT(trans != NULL, RET_ERR_ASYNC(handle, ALPM_ERR_TRANS_NULL, -1));
 	ASSERT(trans->state == STATE_COMMITING || trans->state == STATE_INTERRUPTED,
-			RET_ERR(handle, ALPM_ERR_TRANS_TYPE, -1));
+			RET_ERR_ASYNC(handle, ALPM_ERR_TRANS_TYPE, -1));
 
 	trans->state = STATE_INTERRUPTED;
 
diff --git a/lib/libalpm/util.h b/lib/libalpm/util.h
index 9817939..f47c26e 100644
--- a/lib/libalpm/util.h
+++ b/lib/libalpm/util.h
@@ -71,6 +71,10 @@ void _alpm_alloc_fail(size_t size);
 	(handle)->pm_errno = (err); \
 	return (ret); } while(0)
 
+#define RET_ERR_ASYNC(handle, err, ret) do { \
+	(handle)->pm_errno = (err); \
+	return (ret); } while(0)
+
 #define DOUBLE_EQ(x, y) (fabs((x) - (y)) < DBL_EPSILON)
 
 #define CHECK_HANDLE(handle, action) do { if(!(handle)) { action; } (handle)->pm_errno = 0; } while(0)
-- 
2.7.1