tests: mockup: validate the chip index where applicable

In functions that take the chip index as argument: let's verify that
its value is valid i.e. it refers to an existing chip to avoid potential
segfaults.

While we're at it: delegate the validation of arguments in mockup getter
helpers to a separate routine.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/tests/mockup/gpio-mockup.c b/tests/mockup/gpio-mockup.c
index 56920b7d472caf6eda246eea1b5d57dc8d783de7..608a76409c01ce75a7316be415e906b7af18d141 100644 (file)
--- a/tests/mockup/gpio-mockup.c
+++ b/tests/mockup/gpio-mockup.c
@@ -375,34 +375,43 @@ EXPORT int gpio_mockup_remove(struct gpio_mockup *ctx)
        return 0;
 }
 
-EXPORT const char *
-gpio_mockup_chip_name(struct gpio_mockup *ctx, unsigned int idx)
+static bool index_valid(struct gpio_mockup *ctx, unsigned int idx)
 {
        if (!ctx->chips) {
                errno = ENODEV;
-               return NULL;
+               return false;
+       }
+
+       if (idx >= ctx->num_chips) {
+               errno = EINVAL;
+               return false;
        }
 
+       return true;
+}
+
+EXPORT const char *
+gpio_mockup_chip_name(struct gpio_mockup *ctx, unsigned int idx)
+{
+       if (!index_valid(ctx, idx))
+               return NULL;
+
        return ctx->chips[idx]->name;
 }
 
 EXPORT const char *
 gpio_mockup_chip_path(struct gpio_mockup *ctx, unsigned int idx)
 {
-       if (!ctx->chips) {
-               errno = ENODEV;
+       if (!index_valid(ctx, idx))
                return NULL;
-       }
 
        return ctx->chips[idx]->path;
 }
 
 EXPORT int gpio_mockup_chip_num(struct gpio_mockup *ctx, unsigned int idx)
 {
-       if (!ctx->chips) {
-               errno = ENODEV;
+       if (!index_valid(ctx, idx))
                return -1;
-       }
 
        return ctx->chips[idx]->num;
 }
@@ -432,10 +441,8 @@ EXPORT int gpio_mockup_get_value(struct gpio_mockup *ctx,
        char buf;
        int fd;
 
-       if (!ctx->chips) {
-               errno = ENODEV;
+       if (!index_valid(ctx, chip_idx))
                return -1;
-       }
 
        fd = debugfs_open(ctx->chips[chip_idx]->num, line_offset, O_RDONLY);
        if (fd < 0)
@@ -465,10 +472,8 @@ EXPORT int gpio_mockup_set_pull(struct gpio_mockup *ctx,
        ssize_t wr;
        int fd;
 
-       if (!ctx->chips) {
-               errno = ENODEV;
+       if (!index_valid(ctx, chip_idx))
                return -1;
-       }
 
        fd = debugfs_open(ctx->chips[chip_idx]->num, line_offset, O_WRONLY);
        if (fd < 0)