From: Bartosz Golaszewski <bartekgola@gmail.com>
Date: Wed, 11 Jan 2017 10:06:50 +0000 (+0100)
Subject: iterators: extend chip iterator error handling
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8ea028f0d5dc60b1fc42fb5a9dbfbca3de6ec9f6;p=qemu-gpiodev%2Flibgpiod.git

iterators: extend chip iterator error handling

Add a function that allows to retrieve the name of the gpiochip that
we failed to open from an iterator routine. Use it in gpiodetect.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
---

diff --git a/core.c b/core.c
index e7696d7..2e1e360 100644
--- a/core.c
+++ b/core.c
@@ -63,6 +63,7 @@ struct gpiod_chip_iter
 	DIR *dir;
 	struct gpiod_chip *current;
 	int state;
+	char *failed_chip;
 };
 
 static const char dev_dir[] = "/dev/";
@@ -955,6 +956,8 @@ void gpiod_chip_iter_free(struct gpiod_chip_iter *iter)
 void gpiod_chip_iter_free_noclose(struct gpiod_chip_iter *iter)
 {
 	closedir(iter->dir);
+	if (iter->failed_chip)
+		free(iter->failed_chip);
 	free(iter);
 }
 
@@ -976,10 +979,17 @@ struct gpiod_chip * gpiod_chip_iter_next(struct gpiod_chip_iter *iter)
 				 sizeof(cdev_prefix) - 1);
 		if (status == 0) {
 			iter->state = CHIP_ITER_INIT;
+			if (iter->failed_chip) {
+				free(iter->failed_chip);
+				iter->failed_chip = NULL;
+			}
 
 			chip = gpiod_chip_open_by_name(dentry->d_name);
-			if (!chip)
+			if (!chip) {
 				iter->state = CHIP_ITER_ERR;
+				iter->failed_chip = strdup(dentry->d_name);
+				/* No point in an error check here. */
+			}
 
 			iter->current = chip;
 			return iter->current;
@@ -999,3 +1009,9 @@ bool gpiod_chip_iter_iserr(struct gpiod_chip_iter *iter)
 {
 	return iter->state == CHIP_ITER_ERR;
 }
+
+const char *
+gpiod_chip_iter_failed_chip(struct gpiod_chip_iter *iter)
+{
+	return iter->failed_chip;
+}
diff --git a/gpiod.h b/gpiod.h
index 5cf3254..4d2e7bc 100644
--- a/gpiod.h
+++ b/gpiod.h
@@ -723,6 +723,19 @@ bool gpiod_chip_iter_done(struct gpiod_chip_iter *iter) GPIOD_API;
  */
 bool gpiod_chip_iter_iserr(struct gpiod_chip_iter *iter) GPIOD_API;
 
+/**
+ * @brief Get the name of the gpiochip that we failed to access.
+ * @param iter The gpiochip iterator object.
+ * @return If gpiod_chip_iter_iserr() returned true, this function returns a
+ *         pointer to the name of the gpiochip that we failed to access.
+ *         If there was no error this function returns NULL.
+ *
+ * NOTE: this function will return NULL if the internal memory allocation
+ * fails.
+ */
+const char *
+gpiod_chip_iter_failed_chip(struct gpiod_chip_iter *iter) GPIOD_API;
+
 /**
  * @brief GPIO line iterator structure.
  *
diff --git a/gpiodetect.c b/gpiodetect.c
index aab022d..c35b618 100644
--- a/gpiodetect.c
+++ b/gpiodetect.c
@@ -66,7 +66,8 @@ int main(int argc, char **argv)
 
 	gpiod_foreach_chip(iter, chip) {
 		if (gpiod_chip_iter_iserr(iter))
-			die_perror("error accessing gpiochip");
+			die_perror("error accessing gpiochip %s",
+				   gpiod_chip_iter_failed_chip(iter));
 
 		printf("%s [%s] (%u lines)\n",
 		       gpiod_chip_name(chip),