Add environment file to enable parallel tests

lib/libusbx52/libusbx52.h

@@ -35,19 +35,35 @@ struct libusb_device_handle {
 };
 
 /**
- * @brief File location of the device list file
+ * @brief Device list file environment variable
+ *
+ * This is used by the test driver to create a temporary environment for
+ * the device list
+ */
+#define INPUT_DEVICE_LIST_ENV           "LIBUSBX52_DEVICE_LIST"
+
+/**
+ * @brief Default file location of the device list file
  *
  * This file contains a list of VIDs and PIDs in hexadecimal format separated
  * by spaces. There must be an even number of entries, each pair corresponding
  * to a (VID, PID) tuple identifying a single USB device.
  */
-#define INPUT_DEVICE_LIST_FILE  "/tmp/libusbx52_device_list"
+#define DEFAULT_INPUT_DEVICE_LIST_FILE  "/tmp/libusbx52_device_list"
 
 /**
- * @brief File location of the communication data file
+ * @brief Output data environment variable
+ *
+ * This is used by the test driver to create a temporary environment for
+ * the output data
+ */
+#define OUTPUT_DATA_FILE_ENV            "LIBUSBX52_OUTPUT_DATA"
+
+/**
+ * @brief Default file location of the communication data file
  *
  * This file contains the libusb APIs called by libx52, after a device has
  * been opened, i.e., all APIs that operate on a libusb_device_handle
  */
-#define OUTPUT_DATA_FILE        "/tmp/libusbx52_output_data"
+#define DEFAULT_OUTPUT_DATA_FILE        "/tmp/libusbx52_output_data"
 

lib/libusbx52/usb_x52_stub.c

@@ -21,6 +21,7 @@ int libusb_init(libusb_context **ctx)
     int vid;
     int pid;
     int parsed;
+    char *dev_list_file;
     FILE *dev_list;
     int i;
 
@@ -37,7 +38,15 @@ int libusb_init(libusb_context **ctx)
         goto init_err_recovery;
     }
 
-    dev_list = fopen(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;
@@ -182,6 +191,8 @@ 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) {
@@ -194,7 +205,16 @@ int libusb_open(libusb_device *dev, libusb_device_handle **handle)
     /* Populate the handle structure with the right values */
     tmp_hdl->ctx = dev->context;
     tmp_hdl->dev = dev;
-    tmp_hdl->packet_data_file = fopen(OUTPUT_DATA_FILE, "w");
+
+    /*
+     * Get the name of the output data file from the environment,
+     * 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) {

lib/libusbx52/util/create_device_list.c

@@ -12,12 +12,14 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include "libusbx52.h"
 
 int main(int argc, char *argv[])
 {
+    char *data_file;
     FILE *data;
     char **id_pair;
     int vid;
@@ -25,10 +27,13 @@ int main(int argc, char *argv[])
     int parsed;
     int i;
 
-    data = fopen(INPUT_DEVICE_LIST_FILE, "w");
+    data_file = getenv(INPUT_DEVICE_LIST_ENV);
+    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",
-            INPUT_DEVICE_LIST_FILE);
+        fprintf(stderr, "Unable to open %s for writing\n", data_file);
         fprintf(stderr, "%s\n", strerror(errno));
     }