Move opening from environment into separate function

lib/libusbx52/Makefile.am

@@ -14,17 +14,17 @@ CC = $(PTHREAD_CC)
 # libusb stub library for use by test programs
 check_LTLIBRARIES = libusbx52.la
 
-libusbx52_la_SOURCES = usb_x52_stub.c
+libusbx52_la_SOURCES = usb_x52_stub.c fopen_env.c
 libusbx52_la_CFLAGS = @LIBUSB_CFLAGS@
 libusbx52_la_LDFLAGS = -rpath /nowhere -module
 
 # Utility programs for use by tests
 check_PROGRAMS = x52test_create_device_list x52test_log_actions
 
-x52test_create_device_list_SOURCES = util/create_device_list.c
+x52test_create_device_list_SOURCES = util/create_device_list.c $(libusbx52_la_SOURCES)
 x52test_create_device_list_CFLAGS = @LIBUSB_CFLAGS@
 
-x52test_log_actions_SOURCES = util/log_actions.c usb_x52_stub.c
+x52test_log_actions_SOURCES = util/log_actions.c $(libusbx52_la_SOURCES)
 x52test_log_actions_CFLAGS = @X52_INCLUDE@ @LIBUSB_CFLAGS@
 
 EXTRA_DIST = README.md libusbx52.h

lib/libusbx52/fopen_env.c

@@ -0,0 +1,22 @@
+/*
+ * LibUSB stub driver for testing the Saitek X52/X52 Pro
+ * Common functionality
+ *
+ * Copyright (C) 2020 Nirenjan Krishnan (nirenjan@nirenjan.org)
+ *
+ * SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+FILE * fopen_env(const char *env, const char *env_default, const char *mode)
+{
+    // Get the filename from the environment. Use defaults if unset or empty
+    const char *filename = getenv(env);
+    if (filename == NULL || filename[0] == '\0') {
+        filename = env_default;
+    }
+
+    return fopen(filename, mode);
+}

lib/libusbx52/libusbx52.h

@@ -7,7 +7,6 @@
  */
 
 #include <stdio.h>
-// #include <libusb-1.0/libusb.h>
 #include <libusb.h>
 
 struct libusb_device {
@@ -65,3 +64,5 @@ struct libusb_device_handle {
  */
 #define DEFAULT_OUTPUT_DATA_FILE        "/tmp/libusbx52_output_data"
 
+/* Open file from environment variable */
+FILE * fopen_env(const char *env, const char *env_default, const char *mode);

lib/libusbx52/usb_x52_stub.c

@@ -21,7 +21,6 @@ int libusb_init(libusb_context **ctx)
     unsigned int vid;
     unsigned int pid;
     int parsed;
-    char *dev_list_file;
     FILE *dev_list;
     int i;
 
@@ -38,15 +37,7 @@ int libusb_init(libusb_context **ctx)
         goto init_err_recovery;
     }
 
-    /*
+    dev_list = fopen_env(INPUT_DEVICE_LIST_ENV, DEFAULT_INPUT_DEVICE_LIST_FILE, "r");
-     * Get the device file name from the environment,
-     * use a default name if unset or empty
-     */
-    dev_list_file = getenv(INPUT_DEVICE_LIST_ENV);
-    if (dev_list_file == NULL || dev_list_file[0] == '\0') {
-        dev_list_file = DEFAULT_INPUT_DEVICE_LIST_FILE;
-    }
-    dev_list = fopen(dev_list_file, "r");
     if (dev_list == NULL) {
         rc = LIBUSB_ERROR_IO;
         goto init_err_recovery;
@@ -210,8 +201,6 @@ int libusb_get_device_descriptor(libusb_device *dev,
 
 int libusb_open(libusb_device *dev, libusb_device_handle **handle)
 {
-    char *output_data_file;
-
     /* Allocate a handle for the application */
     libusb_device_handle *tmp_hdl = calloc(1, sizeof(*tmp_hdl));
     if (tmp_hdl == NULL) {
@@ -225,15 +214,8 @@ int libusb_open(libusb_device *dev, libusb_device_handle **handle)
     tmp_hdl->ctx = dev->context;
     tmp_hdl->dev = dev;
 
-    /*
+    tmp_hdl->packet_data_file = fopen_env(OUTPUT_DATA_FILE_ENV,
-     * Get the name of the output data file from the environment,
+                                          DEFAULT_OUTPUT_DATA_FILE, "w");
-     * use a default name if the environment variable is unset or empty
-     */
-    output_data_file = getenv(OUTPUT_DATA_FILE_ENV);
-    if (output_data_file == NULL || output_data_file[0] == '\0') {
-        output_data_file = DEFAULT_OUTPUT_DATA_FILE;
-    }
-    tmp_hdl->packet_data_file = fopen(output_data_file, "w");
 
     /* Make sure that the file opened correctly */
     if (tmp_hdl->packet_data_file == NULL) {
@@ -280,7 +262,7 @@ int libusb_control_transfer(libusb_device_handle *dev_handle,
 {
     /* Always log the control transfer */
     fprintf(dev_handle->packet_data_file,
-        "%s: RqType: %02x bRequest: %02x wValue: %04x wIndex: %04x timeout: %d\n",
+        "%s: RqType: %02x bRequest: %02x wValue: %04x wIndex: %04x timeout: %u\n",
         __func__, request_type, bRequest, wValue, wIndex, timeout);
     if (data != NULL) {
         int i;

lib/libusbx52/util/create_device_list.c

@@ -16,20 +16,15 @@
 
 int main(int argc, char *argv[])
 {
-    char *data_file;
     FILE *data;
     char **id_pair;
     unsigned int vid;
     unsigned int pid;
     int i;
 
-    data_file = getenv(INPUT_DEVICE_LIST_ENV);
+    data = fopen_env(INPUT_DEVICE_LIST_ENV, DEFAULT_INPUT_DEVICE_LIST_FILE, "w");
-    if (data_file == NULL || data_file[0] == '\0') {
-        data_file = DEFAULT_INPUT_DEVICE_LIST_FILE;
-    }
-    data = fopen(data_file, "w");
     if (data == NULL) {
-        fprintf(stderr, "Unable to open %s for writing\n", data_file);
+        fprintf(stderr, "Unable to open device list file for writing\n");
         fprintf(stderr, "%s\n", strerror(errno));
     }