fastrpc: libhexagonrpc: add error API

When the kernel side of FastRPC fails, the return value is -1 and errno
is set. When the remote side of FastRPC fails, the return value is an
AEE error code. It is not specialized for the reverse tunnel. Add an
error API that can convert the return value to a string-based error.

Author: flamingradian

hexagonrpcd/apps_std.c

@@ -20,13 +20,13 @@
  */
 
 #include <errno.h>
+#include <libhexagonrpc/error.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
-#include "aee_error.h"
 #include "interfaces/apps_std.def"
 #include "hexagonfs.h"
 #include "iobuffer.h"

hexagonrpcd/listener.c

@@ -20,12 +20,12 @@
  */
 
 #include <inttypes.h>
+#include <libhexagonrpc/error.h>
 #include <libhexagonrpc/fastrpc.h>
 #include <libhexagonrpc/interfaces/remotectl.def>
 #include <stddef.h>
 #include <stdio.h>
 
-#include "aee_error.h"
 #include "interfaces/adsp_listener.def"
 #include "iobuffer.h"
 #include "listener.h"

hexagonrpcd/localctl.c

@@ -19,13 +19,13 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+#include <libhexagonrpc/error.h>
 #include <libhexagonrpc/interfaces/remotectl.def>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "aee_error.h"
 #include "iobuffer.h"
 #include "listener.h"
 #include "localctl.h"

hexagonrpcd/meson.build

@@ -1,5 +1,4 @@
 executable('hexagonrpcd',
-  'aee_error.c',
   'apps_mem.c',
   'apps_std.c',
   'interfaces.c',

hexagonrpcd/rpcd.c

@@ -21,6 +21,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <libhexagonrpc/error.h>
 #include <libhexagonrpc/fastrpc.h>
 #include <libhexagonrpc/interfaces/remotectl.def>
 #include <misc/fastrpc.h>
@@ -34,7 +35,6 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include "aee_error.h"
 #include "apps_mem.h"
 #include "apps_std.h"
 #include "hexagonfs.h"
@@ -56,17 +56,14 @@ static int remotectl_open(int fd, char *name, struct fastrpc_context **ctx, void
 		       &dlret,
 		       256, err);
 
-	if (ret == -1) {
-		err_cb(strerror(errno));
+	if (ret) {
+		err_cb(hexagonrpc_strerror(errno));
 		return ret;
 	}
 
-	if (dlret == -5) {
+	if (dlret) {
 		err_cb(err);
 		return dlret;
-	} else if (dlret) {
-		err_cb(aee_strerror[dlret]);
-		return dlret;
 	}
 
 	*ctx = fastrpc_create_context(fd, handle);
@@ -85,13 +82,13 @@ static int remotectl_close(struct fastrpc_context *ctx, void (*err_cb)(const cha
 		       &dlret,
 		       256, err);
 
-	if (ret == -1) {
-		err_cb(strerror(errno));
+	if (ret) {
+		err_cb(hexagonrpc_strerror(errno));
 		return ret;
 	}
 
 	if (dlret) {
-		err_cb(aee_strerror[dlret]);
+		err_cb(err);
 		return dlret;
 	}
 

hexagonrpcd/aee_error.h renamed to include/libhexagonrpc/error.h

@@ -2,6 +2,7 @@
  * Imported FastRPC error numbers
  *
  * Copyright (c) 2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023, The Sensor Shell Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -83,6 +84,6 @@
 #define AEE_ECPUEXCEPTION	48
 #define AEE_EREADONLY		49
 
-extern const char *aee_strerror[];
+const char *hexagonrpc_strerror(int ret);
 
 #endif

hexagonrpcd/aee_error.c renamed to libhexagonrpc/error.c

@@ -2,6 +2,7 @@
  * Imported FastRPC error messages
  *
  * Copyright (c) 2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023, The Sensor Shell Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -29,7 +30,10 @@
  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-const char *aee_strerror[] = {
+#include <errno.h>
+#include <string.h>
+
+static const char *err_tab[] = {
 	"No error",
 	"General failure",
 	"Insufficient RAM",
@@ -81,3 +85,13 @@ const char *aee_strerror[] = {
 	"A CPU exception occurred",
 	"Cannot change read-only object or parameter",
 };
+
+const char *hexagonrpc_strerror(int ret)
+{
+	if (ret == -1)
+		return strerror(errno);
+	else if (ret >= 0 && (unsigned int) ret < sizeof(err_tab) / sizeof(*err_tab))
+		return err_tab[ret];
+
+	return "Unknown error";
+}

libhexagonrpc/meson.build

@@ -1,5 +1,6 @@
 libhexagonrpc = shared_library('hexagonrpc',
   'context.c',
+  'error.c',
   'fastrpc.c',
   'interfaces.c',
   'session.c',