am7xxx: add a simple logging infrastructure

[libam7xxx.git] / src / am7xxx.c

diff --git a/src/am7xxx.c b/src/am7xxx.c
index 272a249..4cfc9a9 100644 (file)
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

+#include <stdarg.h>

 #include <errno.h>
 #include <libusb.h>
 
 #include <errno.h>
 #include <libusb.h>
 


@@ -27,6 +28,27 @@
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 

+/* If we're not using GNU C, elide __attribute__
+ * taken from: http://unixwiz.net/techtips/gnu-c-attributes.html)
+ */
+#ifndef __GNUC__
+#  define  __attribute__(x)  /*NOTHING*/
+#endif
+
+static void log_message(am7xxx_context *ctx,
+                       int level,
+                       const char *function,
+                       int line,
+                       const char *fmt,
+                       ...) __attribute__ ((format (printf, 5, 6)));
+
+#define fatal(...)        log_message(NULL, AM7XXX_LOG_FATAL,   __func__, __LINE__, __VA_ARGS__)
+#define error(ctx, ...)   log_message(ctx,  AM7XXX_LOG_ERROR,   __func__, __LINE__, __VA_ARGS__)
+#define warning(ctx, ...) log_message(ctx,  AM7XXX_LOG_WARNING, __func__, 0,        __VA_ARGS__)
+#define info(ctx, ...)    log_message(ctx,  AM7XXX_LOG_INFO,    __func__, 0,        __VA_ARGS__)
+#define debug(ctx, ...)   log_message(ctx,  AM7XXX_LOG_DEBUG,   __func__, 0,        __VA_ARGS__)
+#define trace(ctx, ...)   log_message(ctx,  AM7XXX_LOG_TRACE,   NULL,     0,        __VA_ARGS__)
+

 struct am7xxx_usb_device_descriptor {
        const char *name;
        uint16_t vendor_id;
 struct am7xxx_usb_device_descriptor {
        const char *name;
        uint16_t vendor_id;


@@ -55,6 +77,14 @@ static struct am7xxx_usb_device_descriptor supported_devices[] = {
 struct _am7xxx_device {
        libusb_device_handle *usb_device;
        uint8_t buffer[AM7XXX_HEADER_WIRE_SIZE];
 struct _am7xxx_device {
        libusb_device_handle *usb_device;
        uint8_t buffer[AM7XXX_HEADER_WIRE_SIZE];

+       am7xxx_context *ctx;
+       am7xxx_device *next;
+};
+
+struct _am7xxx_context {
+       libusb_context *usb_context;
+       int log_level;
+       am7xxx_device *devices_list;

 };
 
 typedef enum {
 };
 
 typedef enum {


@@ -315,55 +345,302 @@ static int send_header(am7xxx_device *dev, struct am7xxx_header *h)
        return ret;
 }
 
        return ret;
 }
 

-am7xxx_device *am7xxx_init(void)
+/* When level == AM7XXX_LOG_FATAL do not check the log_level from the context
+ * and print the message unconditionally, this makes it possible to print
+ * fatal messages even early on initialization, before the context has been
+ * set up */
+static void log_message(am7xxx_context *ctx,
+                       int level,
+                       const char *function,
+                       int line,
+                       const char *fmt,
+                       ...)

 {
 {

-       unsigned int i;
+       va_list ap;
+
+       if (level == AM7XXX_LOG_FATAL || (ctx && level <= ctx->log_level)) {
+               if (function) {
+                       fprintf(stderr, "%s", function);
+                       if (line)
+                               fprintf(stderr, "[%d]", line);
+                       fprintf(stderr, ": ");
+               }

 
 

-       am7xxx_device *dev = malloc(sizeof(*dev));
-       if (dev == NULL) {
+               va_start(ap, fmt);
+               vfprintf(stderr, fmt, ap);
+               va_end(ap);
+       }
+
+       return;
+}
+
+static am7xxx_device *add_new_device(am7xxx_context *ctx)
+{
+       am7xxx_device **devices_list;
+       am7xxx_device *new_device;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return NULL;
+       }
+
+       devices_list = &(ctx->devices_list);
+
+       new_device = malloc(sizeof(*new_device));
+       if (new_device == NULL) {

                perror("malloc");
                perror("malloc");

+               return NULL;
+       }
+       memset(new_device, 0, sizeof(*new_device));
+
+       new_device->ctx = ctx;
+
+       if (*devices_list == NULL) {
+               *devices_list = new_device;
+       } else {
+               am7xxx_device *prev = *devices_list;
+               while (prev->next)
+                       prev = prev->next;
+               prev->next = new_device;
+       }
+       return new_device;
+}
+
+static am7xxx_device *find_device(am7xxx_context *ctx,
+                                 unsigned int device_index)
+{
+       unsigned int i = 0;
+       am7xxx_device *current;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return NULL;
+       }
+
+       current = ctx->devices_list;
+       while (current && i++ < device_index)
+               current = current->next;
+
+       return current;
+}
+
+typedef enum {
+       SCAN_OP_BUILD_DEVLIST,
+       SCAN_OP_OPEN_DEVICE,
+} scan_op;
+
+/**
+ * This is where the central logic of multi-device support is.
+ *
+ * When 'op' == SCAN_OP_BUILD_DEVLIST the parameters 'open_device_index' and
+ * 'dev' are ignored; the function returns 0 on success and a negative value
+ * on error.
+ *
+ * When 'op' == SCAN_OP_OPEN_DEVICE the function opens the supported USB
+ * device with index 'open_device_index' and returns the correspondent
+ * am7xxx_device in the 'dev' parameter; the function returns 0 on success,
+ * 1 if the device was already open and a negative value on error.
+ * 
+ * NOTES:
+ * if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
+ * the caller might want to call am7xxx_shutdown() in order to remove
+ * devices possibly added before the failure.
+ */
+static int scan_devices(am7xxx_context *ctx, scan_op op,
+                       unsigned int open_device_index, am7xxx_device **dev)
+{
+       int num_devices;
+       libusb_device** list;
+       unsigned int current_index;
+       int i;
+       int ret;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+       if (op == SCAN_OP_BUILD_DEVLIST && ctx->devices_list != NULL) {
+               fprintf(stderr, "%s: device scan done already? Abort!\n", __func__);
+               return -EINVAL;
+       }
+
+       num_devices = libusb_get_device_list(ctx->usb_context, &list);
+       if (num_devices < 0) {
+               ret = -ENODEV;

                goto out;
        }
                goto out;
        }

-       memset(dev, 0, sizeof(*dev));
-
-       libusb_init(NULL);
-       libusb_set_debug(NULL, 3);
-
-       for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {
-               dev->usb_device = libusb_open_device_with_vid_pid(NULL,
-                                                     supported_devices[i].vendor_id,
-                                                     supported_devices[i].product_id);
-               if (dev->usb_device) {
-                       printf("%s: device found: %s\n", __func__, supported_devices[i].name);
-                       break;
+
+       current_index = 0;
+       for (i = 0; i < num_devices; i++) {
+               struct libusb_device_descriptor desc;
+               unsigned int j;
+
+               ret = libusb_get_device_descriptor(list[i], &desc);
+               if (ret < 0)
+                       continue;
+
+               for (j = 0; j < ARRAY_SIZE(supported_devices); j++) {
+                       if (desc.idVendor == supported_devices[j].vendor_id
+                           && desc.idProduct == supported_devices[j].product_id) {
+
+                               if (op == SCAN_OP_BUILD_DEVLIST) {
+                                       am7xxx_device *new_device;
+                                       /* debug */
+                                       printf("am7xxx device found, index: %d, name: %s\n",
+                                              current_index,
+                                              supported_devices[j].name);
+                                       new_device = add_new_device(ctx);
+                                       if (new_device == NULL) {
+                                               /* XXX, the caller may want
+                                                * to call am7xxx_shutdown() if
+                                                * we fail here, as we may have
+                                                * added some devices already
+                                                */
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+                               } else if (op == SCAN_OP_OPEN_DEVICE &&
+                                          current_index == open_device_index) {
+
+                                       *dev = find_device(ctx, open_device_index);
+                                       if (*dev == NULL) {
+                                               ret = -ENODEV;
+                                               goto out;
+                                       }
+
+                                       /* the usb device has already been opened */
+                                       if ((*dev)->usb_device) {
+                                               ret = 1;
+                                               goto out;
+                                       }
+
+                                       ret = libusb_open(list[i], &((*dev)->usb_device));
+                                       if (ret < 0)
+                                               goto out;
+
+                                       libusb_set_configuration((*dev)->usb_device, 1);
+                                       libusb_claim_interface((*dev)->usb_device, 0);
+                                       goto out;
+                               }
+                               current_index++;
+                       }

                }
        }
                }
        }

-       if (dev->usb_device == NULL) {
-               errno = ENODEV;
-               perror("libusb_open_device_with_vid_pid");
-               goto out_libusb_exit;
+
+       /* if we made it up to here we didn't find any device to open */
+       if (op == SCAN_OP_OPEN_DEVICE) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+       /* everything went fine when building the device list */
+       ret = 0;
+out:
+       libusb_free_device_list(list, 1);
+       return ret;
+}
+
+int am7xxx_init(am7xxx_context **ctx)
+{
+       int ret = 0;
+
+       *ctx = malloc(sizeof(**ctx));
+       if (*ctx == NULL) {
+               perror("malloc");
+               ret = -ENOMEM;
+               goto out;

        }
        }

+       memset(*ctx, 0, sizeof(**ctx));

 
 

-       libusb_set_configuration(dev->usb_device, 1);
-       libusb_claim_interface(dev->usb_device, 0);
+       /* Set the highest log level during initialization */
+       (*ctx)->log_level = AM7XXX_LOG_TRACE;

 
 

-       return dev;
+       ret = libusb_init(&((*ctx)->usb_context));
+       if (ret < 0)
+               goto out_free_context;
+
+       libusb_set_debug((*ctx)->usb_context, 3);
+
+       ret = scan_devices(*ctx, SCAN_OP_BUILD_DEVLIST , 0, NULL);
+       if (ret < 0) {
+               fprintf(stderr, "%s: scan_devices failed\n", __func__);
+               am7xxx_shutdown(*ctx);
+               goto out;
+       }
+
+       /* Set a quieter log level as default for normal operation */
+       (*ctx)->log_level = AM7XXX_LOG_ERROR;
+       return 0;

 
 

-out_libusb_exit:
-       libusb_exit(NULL);
-       free(dev);
+out_free_context:
+       free(*ctx);
+       *ctx = NULL;

 out:
 out:

-       return NULL;
+       return ret;
+}
+
+void am7xxx_shutdown(am7xxx_context *ctx)
+{
+       am7xxx_device *current;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return;
+       }
+
+       current = ctx->devices_list;
+       while (current) {
+               am7xxx_device *next = current->next;
+               am7xxx_close_device(current);
+               free(current);
+               current = next;
+       }
+
+       libusb_exit(ctx->usb_context);
+       free(ctx);
+       ctx = NULL;
+}
+
+void am7xxx_set_log_level(am7xxx_context *ctx, am7xxx_log_level log_level)
+{
+       ctx->log_level = log_level;
+}
+
+int am7xxx_open_device(am7xxx_context *ctx, am7xxx_device **dev,
+                      unsigned int device_index)
+{
+       int ret;
+
+       if (ctx == NULL) {
+               fprintf(stderr, "%s: context must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+
+       ret = scan_devices(ctx, SCAN_OP_OPEN_DEVICE, device_index, dev);
+       if (ret < 0) {
+               errno = ENODEV;
+       } else if (ret > 0) {
+               /* warning */
+               fprintf(stderr, "%s: device %d already open\n", __func__, device_index);
+               errno = EBUSY;
+               ret = -EBUSY;
+       }
+
+       return ret;

 }
 
 }
 

-void am7xxx_shutdown(am7xxx_device *dev)
+int am7xxx_close_device(am7xxx_device *dev)

 {
 {

-       if (dev) {
+       if (dev == NULL) {
+               fprintf(stderr, "%s: dev must not be NULL!\n", __func__);
+               return -EINVAL;
+       }
+       if (dev->usb_device) {
+               libusb_release_interface(dev->usb_device, 0);

                libusb_close(dev->usb_device);
                libusb_close(dev->usb_device);

-               libusb_exit(NULL);
-               free(dev);
-               dev = NULL;
+               dev->usb_device = NULL;

        }
        }

+       return 0;

 }
 
 int am7xxx_get_device_info(am7xxx_device *dev,
 }
 
 int am7xxx_get_device_info(am7xxx_device *dev,