Fix a SEGFAULT that happens when textfile_del is called using an empty file.

2 files changed, 26 insertions, 2 deletions

diff --git a/common/test_textfile.c b/common/test_textfile.c
index 5a5b22c5..8b60bbe8 100644
--- a/common/test_textfile.c
+++ b/common/test_textfile.c
@@ -48,6 +48,28 @@ int main(int argc, char *argv[])
 	fd = creat(filename, 0644);
 	close(fd);
 
+	sprintf(key, "00:00:00:00:00:00");
+	if (textfile_del(filename, key) < 0) 
+		fprintf(stderr, "%s (%d)\n", strerror(errno), errno);
+
+	memset(value, 0, sizeof(value));
+	if (textfile_put(filename, key, value) < 0)
+		fprintf(stderr, "%s (%d)\n", strerror(errno), errno);
+
+	str = textfile_get(filename, key);
+	if (!str)
+		fprintf(stderr, "No value for %s\n", key);
+	else
+		free(str);
+
+	if (textfile_del(filename, key) < 0) 
+		fprintf(stderr, "%s (%d)\n", strerror(errno), errno);
+
+	str = textfile_get(filename, key);
+	if (str) {
+		fprintf(stderr, "Found value for %s\n", key);
+		free(str);
+	}
 
 	for (i = 1; i < max + 1; i++) {
 		sprintf(key, "00:00:00:00:00:%02X", i);
diff --git a/common/textfile.c b/common/textfile.c
index bb55109c..84a72b3c 100644
--- a/common/textfile.c
+++ b/common/textfile.c
@@ -143,8 +143,10 @@ static int write_key(const char *pathname, const char *key, const char *value)
 	size = st.st_size;
 
 	if (!size) {
-		pos = lseek(fd, size, SEEK_SET);
-		err = write_key_value(fd, key, value);
+		if (value) {
+			pos = lseek(fd, size, SEEK_SET);
+			err = write_key_value(fd, key, value);
+		}
 		goto unlock;
 	}