* Added telehelper module providing locked read access to shared memory.

diff --git a/Makefile b/Makefile
index 61ab0249bec3cb0c10a2149d056b76675c6f5be9..d70e3ed2a57d7446f6d8e3d087aacd6a99848aa8 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -26,8 +26,8 @@ endif
 
 COMMON_HDR := telemetry.h
 PLUGIN_SRC := teleshmem.cpp shmget.c
-HTTPD_OBJ  := telehttpd.o shmget.o net.o fserv.o tele2json.o
-LOGGER_OBJ := telelogger.o shmget.o tele2json.o
+HTTPD_OBJ  := telehttpd.o shmget.o net.o fserv.o tele2json.o telehelper.o
+LOGGER_OBJ := telelogger.o shmget.o tele2json.o telehelper.o
 
 .PHONY: all clean
 

diff --git a/telehelper.c b/telehelper.c
new file mode 100644 (file)
index 0000000..c7eb790
--- /dev/null
+++ b/telehelper.c
@@ -0,0 +1,80 @@
+// Needed for pthread_rwlock*
+#define _XOPEN_SOURCE 500
+
+#include <string.h>
+
+#include "log.h"
+#include "telehelper.h"
+
+
+uint32_t tele_version( volatile struct telemetry_state_t *tele ) {
+    int e;
+    uint32_t ver = -1;
+
+    e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&tele->rwlock );
+    if ( 0 == e ) {
+        ver = tele->version;
+        pthread_rwlock_unlock( (pthread_rwlock_t *)&tele->rwlock );
+    }
+    else
+        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+    return ver;
+}
+
+uint32_t tele_flags( volatile struct telemetry_state_t *tele ) {
+    int e;
+    uint32_t flags = 0;
+
+    e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&tele->rwlock );
+    if ( 0 == e ) {
+        flags = tele->flags;
+        pthread_rwlock_unlock( (pthread_rwlock_t *)&tele->rwlock );
+    }
+    else
+        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+    return flags;
+}
+
+uint64_t tele_timestamp( volatile struct telemetry_state_t *tele ) {
+    int e;
+    uint64_t ts = -1ULL;
+
+    e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&tele->rwlock );
+    if ( 0 == e ) {
+        ts = tele->timestamp;
+        pthread_rwlock_unlock( (pthread_rwlock_t *)&tele->rwlock );
+    }
+    else
+        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+    return ts;
+}
+
+bool tele_paused( volatile struct telemetry_state_t *tele ) {
+    int e;
+    bool paused = true;
+
+    e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&tele->rwlock );
+    if ( 0 == e ) {
+        paused = tele->paused;
+        pthread_rwlock_unlock( (pthread_rwlock_t *)&tele->rwlock );
+    }
+    else
+        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+    return paused;
+}
+
+int tele_cpy( void *dst, volatile struct telemetry_state_t *tele ) {
+    if ( tele ) {
+        int e;
+        e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&tele->rwlock );
+        if ( 0 == e ) {
+            memcpy( dst, (void *)tele, sizeof *tele );
+            pthread_rwlock_unlock( (pthread_rwlock_t *)&tele->rwlock );
+            return 0;
+        }
+        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+    }
+    memset( dst, 0, sizeof *tele );
+    return -1;
+}
+

diff --git a/telehelper.h b/telehelper.h
new file mode 100644 (file)
index 0000000..aa16765
--- /dev/null
+++ b/telehelper.h
@@ -0,0 +1,29 @@
+#ifndef TELEHELPER_H_
+#define TELEHELPER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "telemetry.h"
+
+
+extern uint32_t tele_version( volatile struct telemetry_state_t *tele );
+
+extern uint32_t tele_flags( volatile struct telemetry_state_t *tele );
+
+extern uint64_t tele_timestamp( volatile struct telemetry_state_t *tele );
+
+extern bool tele_paused( volatile struct telemetry_state_t *tele );
+
+extern int tele_cpy( void *dst, volatile struct telemetry_state_t *tele );
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* TELEHELPER_H_ */

diff --git a/telehttpd.c b/telehttpd.c
index 1c9571b80346ba24f09dfe6a8e38f3b7b24ef21b..6f9e843ecfd7ba1c6248422528ce2c8fb41cb94a 100644 (file)
--- a/telehttpd.c
+++ b/telehttpd.c
@@ -20,6 +20,7 @@
 #include "shmget.h"
 #include "telemetry.h"
 #include "tele2json.h"
+#include "telehelper.h"
 
 struct thread_data_t {
     int sock;
@@ -57,6 +58,8 @@ static void handle_signal(int sig) {
 }
 
 static int init_shm( bool retry ) {
+    uint32_t ver;
+
     do {
         DPRINT( "Trying to attach to shared memory ...\n" );
         telemetry = init_shmget( TELE_SHM_KEY, sizeof *telemetry );
@@ -65,9 +68,9 @@ static int init_shm( bool retry ) {
                 return -1;
             sleep(1);
         }
-        else if ( TELE_VERSION != telemetry->version ) {
+        else if ( TELE_VERSION != ( ver = tele_version( telemetry ) ) ) {
             EPRINT( "telemetry version mismatch: got %u, want %u\n",
-                    (unsigned)telemetry->version, TELE_VERSION );
+                    (unsigned)ver, TELE_VERSION );
             release_shm( TELE_SHM_KEY, (void *)telemetry );
             telemetry = NULL;
             if ( !retry )
@@ -76,7 +79,7 @@ static int init_shm( bool retry ) {
         }
         if ( force_quit )
             return -1;
-    } while ( NULL == telemetry  );
+    } while ( NULL == telemetry );
     DPRINT( "have telemetry version %u\n", (unsigned)telemetry->version );
     return 0;
 }
@@ -84,7 +87,7 @@ static int init_shm( bool retry ) {
 static int check_shm( bool retry ) {
     if ( NULL == telemetry )
         return init_shm( retry );
-    if ( !(telemetry->flags & TELE_FLAG_ALIVE) ) {
+    if ( !( tele_flags( telemetry ) & TELE_FLAG_ALIVE ) ) {
         release_shm( TELE_SHM_KEY, (void *)telemetry );
         telemetry = NULL;
         return init_shm( retry );
@@ -276,19 +279,8 @@ static int serve_http(void) {
         if ( 0 < as ) {
             if ( NULL != (td = malloc( sizeof *td )) ) {
                 td->sock = as;
-                if ( telemetry ) {
-                    int e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&telemetry->rwlock );
-                    if ( 0 != e ) {
-                        EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
-                        return -1;
-                    }
-                    memcpy( &td->tele, (void *)telemetry, sizeof td->tele );
-                    pthread_rwlock_unlock( (pthread_rwlock_t *)&telemetry->rwlock );
-                }
-                else {
+                if ( 0 != tele_cpy( &td->tele, telemetry ) )
                     DPRINT( "No telemetry, serving dummy data\n" );
-                    memset( &td->tele, 0, sizeof td->tele );
-                }
                 pthread_attr_init( &attr );
                 pthread_attr_setdetachstate( &attr, PTHREAD_CREATE_DETACHED );
                 if ( 0 != pthread_create( &tid, &attr, handle_conn, td ) ) {

diff --git a/telelogger.c b/telelogger.c
index 8223e8d159e66e4ab090e73831cb5030428c0c70..8cb523ca6bef0a8fd0784d12abd6aa694f44c6b4 100644 (file)
--- a/telelogger.c
+++ b/telelogger.c
@@ -14,6 +14,7 @@
 #include "shmget.h"
 #include "telemetry.h"
 #include "tele2json.h"
+#include "telehelper.h"
 
 static volatile struct telemetry_state_t *telemetry;
 
@@ -38,6 +39,8 @@ static void msleep( int ms ) {
 }
 
 static int init_shm( bool retry ) {
+    uint32_t ver;
+
     do {
         DPRINT( "Trying to attach to shared memory ...\n" );
         telemetry = init_shmget( TELE_SHM_KEY, sizeof *telemetry );
@@ -46,9 +49,9 @@ static int init_shm( bool retry ) {
                 return -1;
             sleep(1);
         }
-        else if ( TELE_VERSION != telemetry->version ) {
+        else if ( TELE_VERSION != ( ver = tele_version( telemetry ) ) ) {
             DPRINT( "telemetry version mismatch: got %u, want %u\n",
-                    (unsigned)telemetry->version, TELE_VERSION );
+                    (unsigned)ver, TELE_VERSION );
             if ( !retry )
                 return -1;
             release_shm( TELE_SHM_KEY, (void *)telemetry );
@@ -65,7 +68,7 @@ static int init_shm( bool retry ) {
 static int check_shm( bool retry ) {
     if ( NULL == telemetry )
         return init_shm( retry );
-    if ( !(telemetry->flags & TELE_FLAG_ALIVE) ) {
+    if ( !( tele_flags( telemetry ) & TELE_FLAG_ALIVE ) ) {
         release_shm( TELE_SHM_KEY, (void *)telemetry );
         telemetry = NULL;
         return init_shm( retry );
@@ -74,37 +77,29 @@ static int check_shm( bool retry ) {
 }
 
 static int log_console( int cnt, int delay ) {
-    int e;
     char buf[4096];
     bool forever = !cnt;
     struct telemetry_state_t tele;
 
-    last_timestamp = telemetry->timestamp;
+    last_timestamp = tele_timestamp( telemetry );
     while ( forever || cnt-- > 0 ) {
         if ( 0 != check_shm( cfg.retry ) )
             return -1;
-
-        e = pthread_rwlock_rdlock( (pthread_rwlock_t *)&telemetry->rwlock );
-        if ( 0 != e ) {
-            EPRINT( "pthread_rwlock_rdlock: %s\n", strerror( e ) );
+        if ( 0 != tele_cpy( &tele, telemetry ) )
             return -1;
-        }
-        memcpy( &tele, (void *)telemetry, sizeof tele );
-        pthread_rwlock_unlock( (pthread_rwlock_t *)&telemetry->rwlock );
-
         if ( tele2json( buf, sizeof buf, &tele ) > 0 )
             puts( buf );
 
         if ( forever || cnt > 0 ) {
-            if ( last_paused && telemetry->paused && cfg.pause ) {
-                while ( last_paused && telemetry->paused ) {
+            if ( last_paused && tele_paused( telemetry ) && cfg.pause ) {
+                while ( last_paused && tele_paused( telemetry ) ) {
                     if ( 0 != check_shm( cfg.retry ) )
                         return -1;
                     usleep( 10000 );
                 }
             }
-            else if ( last_timestamp == telemetry->timestamp && cfg.pause ) {
-                while ( last_timestamp == telemetry->timestamp ) {
+            else if ( last_timestamp == tele_timestamp( telemetry ) && cfg.pause ) {
+                while ( last_timestamp == tele_timestamp( telemetry ) ) {
                     if ( 0 != check_shm( cfg.retry ) )
                         return -1;
                     msleep( delay );
@@ -112,8 +107,8 @@ static int log_console( int cnt, int delay ) {
             }
             else
                 msleep( delay );
-            last_paused = telemetry->paused;
-            last_timestamp = telemetry->timestamp;
+            last_paused = tele_paused( telemetry );
+            last_timestamp = tele_timestamp( telemetry );
         }
     }
     return 0;