utils: Fix return value handling

Before this patch,
read_int() ignores the return value of fscanf(), file_read_value()
checks for only EOF instead of all failures of a fscanf call and
check_window_size() ignores the return value of an ioctl call.

This patch fixes the error checking for all of the above.

Signed-off-by: Tuukka Tikkanen <tuukka.tikkanen@linaro.org>

Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/utils.c b/utils.c
index 0da877c..73350b7 100644
--- a/utils.c
+++ b/utils.c
@@ -57,6 +57,7 @@ int write_int(const char *path, int val)
 int read_int(const char *path, int *val)
 {
 	FILE *f;
+	int ret;
 
 	f = fopen(path, "r");
 
@@ -65,10 +66,15 @@ int read_int(const char *path, int *val)
 		return -1;
 	}
 
-	fscanf(f, "%d", val);
-
+	ret = fscanf(f, "%d", val);
 	fclose(f);
 
+	if (ret != 1) {
+		fprintf(stderr,
+			"Warning: failed to parse integer from %s\n", path);
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -113,7 +119,7 @@ int file_read_value(const char *path, const char *name,
 		goto out_free;
 	}
 
-	ret = fscanf(file, format, value) == EOF ? -1 : 0;
+	ret = fscanf(file, format, value) != 1 ? -1 : 0;
 
 	fclose(file);
 out_free:
@@ -191,7 +197,8 @@ int check_window_size(void)
 		return 0;
 
 	/* Get terminal window size */
-	ioctl(STDOUT_FILENO, TIOCGWINSZ, &winsize);
+	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &winsize) == -1)
+		return -1;
 
 	if (winsize.ws_col >= 80)
 		return 0;