diff options
| -rw-r--r-- | include/qemu-common.h | 8 | ||||
| -rw-r--r-- | util/id.c | 37 |
2 files changed, 45 insertions, 0 deletions
diff --git a/include/qemu-common.h b/include/qemu-common.h index 0bd212b218..2f74540a87 100644 --- a/include/qemu-common.h +++ b/include/qemu-common.h @@ -246,6 +246,14 @@ int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end, #define STR_OR_NULL(str) ((str) ? (str) : "null") /* id.c */ + +typedef enum IdSubSystems { + ID_QDEV, + ID_BLOCK, + ID_MAX /* last element, used as array size */ +} IdSubSystems; + +char *id_generate(IdSubSystems id); bool id_wellformed(const char *id); /* path.c */ @@ -26,3 +26,40 @@ bool id_wellformed(const char *id) } return true; } + +#define ID_SPECIAL_CHAR '#' + +static const char *const id_subsys_str[] = { + [ID_QDEV] = "qdev", + [ID_BLOCK] = "block", +}; + +/* + * Generates an ID of the form PREFIX SUBSYSTEM NUMBER + * where: + * + * - PREFIX is the reserved character '#' + * - SUBSYSTEM identifies the subsystem creating the ID + * - NUMBER is a decimal number unique within SUBSYSTEM. + * + * Example: "#block146" + * + * Note that these IDs do not satisfy id_wellformed(). + * + * The caller is responsible for freeing the returned string with g_free() + */ +char *id_generate(IdSubSystems id) +{ + static uint64_t id_counters[ID_MAX]; + uint32_t rnd; + + assert(id < ID_MAX); + assert(id_subsys_str[id]); + + rnd = g_random_int_range(0, 100); + + return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR, + id_subsys_str[id], + id_counters[id]++, + rnd); +} |