Currently it is impossible to set an option in a config file to an empty string, because the parser matches only lines containing non-empty strings between double-quotes.
As sscanf() "[" conversion specifier only matches non-empty strings, add a special case for empty strings. Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> --- Changes v1 -> v2: * Move value[0]='\0' assignment outside if condition. Nobody seemed to like the comma operator usage in v1 (including myself), and then I noticed that it was also making checkpatch.pl sad. --- util/qemu-config.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/util/qemu-config.c b/util/qemu-config.c index 2d32ce7..a393a3d 100644 --- a/util/qemu-config.c +++ b/util/qemu-config.c @@ -413,7 +413,9 @@ int qemu_config_parse(FILE *fp, QemuOptsList **lists, const char *fname) opts = qemu_opts_create(list, NULL, 0, &error_abort); continue; } - if (sscanf(line, " %63s = \"%1023[^\"]\"", arg, value) == 2) { + value[0] = '\0'; + if (sscanf(line, " %63s = \"%1023[^\"]\"", arg, value) == 2 || + sscanf(line, " %63s = \"\"", arg) == 1) { /* arg = value */ if (opts == NULL) { error_report("no group defined"); -- 2.1.0