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authorSaya Sugiura <ssugiura@jp.adit-jv.com>2018-05-22 20:40:51 +0900
committerSaya Sugiura <ssugiura@jp.adit-jv.com>2019-04-24 17:13:57 +0900
commit1348d1c07dbda69c32317738b8e9c69734f181c3 (patch)
tree2fe7669cd7d20bc2ee2d5ab5a24a6ebe2bd32ef5
parent37e8bc12a7e86fa54b3a5f260b45fd730a5a59a6 (diff)
downloadDLT-daemon-1348d1c07dbda69c32317738b8e9c69734f181c3.tar.gz
lib: daemon: Fix sem lock potential issue
sem_wait may return an error if a signal is received while waiting for the lock,and therefore not take the lock before returning. Changed to have a while loop. Signed-off-by: Saya Sugiura <ssugiura@jp.adit-jv.com>
-rw-r--r--include/dlt/dlt_user.h7
-rw-r--r--src/daemon/dlt_daemon_common.h8
2 files changed, 11 insertions, 4 deletions
diff --git a/include/dlt/dlt_user.h b/include/dlt/dlt_user.h
index d736032..b885eaf 100644
--- a/include/dlt/dlt_user.h
+++ b/include/dlt/dlt_user.h
@@ -94,8 +94,11 @@ extern "C" {
# define DLT_USER_RESENDBUF_MAX_SIZE (DLT_USER_BUF_MAX_SIZE + 100) /**< Size of resend buffer; Max DLT message size is 1390 bytes plus some extra header space */
/* Use a semaphore or mutex from your OS to prevent concurrent access to the DLT buffer. */
-# define DLT_SEM_LOCK() { sem_wait(&dlt_mutex); }
-# define DLT_SEM_FREE() { sem_post(&dlt_mutex); }
+#define DLT_SEM_LOCK() do{\
+ while ((sem_wait(&dlt_mutex) == -1) && (errno == EINTR)) \
+ continue; /* Restart if interrupted */ \
+ } while(0)
+#define DLT_SEM_FREE() { sem_post(&dlt_mutex); }
/**
* This structure is used for every context used in an application.
diff --git a/src/daemon/dlt_daemon_common.h b/src/daemon/dlt_daemon_common.h
index 112cb92..be29bca 100644
--- a/src/daemon/dlt_daemon_common.h
+++ b/src/daemon/dlt_daemon_common.h
@@ -97,8 +97,12 @@ extern "C" {
/* Use a semaphore or mutex from your OS to prevent concurrent access to the DLT buffer. */
-# define DLT_DAEMON_SEM_LOCK() { sem_wait(&dlt_daemon_mutex); }
-# define DLT_DAEMON_SEM_FREE() { sem_post(&dlt_daemon_mutex); }
+#define DLT_DAEMON_SEM_LOCK() do{\
+ while ((sem_wait(&dlt_daemon_mutex) == -1) && (errno == EINTR)) \
+ continue; /* Restart if interrupted */ \
+ } while(0)
+
+#define DLT_DAEMON_SEM_FREE() { sem_post(&dlt_daemon_mutex); }
extern sem_t dlt_daemon_mutex;
/**