libubox - uloop runqueue ustream
事件处理循环(uloop.c/h)
接口说明
主框架
/** * 初始化事件循环 */
int uloop_init(void) /** * 事件循环主处理入口 */ void uloop_run(void) /** * 销毁事件循环 */ void uloop_done(void) 描述符事件
/** * 注册一个新描述符到事件处理循环 */
int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
/** * 从事件处理循环中销毁指定描述符 */
int uloop_fd_delete(struct uloop_fd *sock)
定时器事件
/** * 注册一个新定时器 */
int uloop_timeout_add(struct uloop_timeout *timeout) /** * 设置定时器超时时间(毫秒)，并添加 */ int uloop_timeout_set(struct uloop_timeout *timeout, int msecs) /** * 销毁指定定时器 */ int uloop_timeout_cancel(struct uloop_timeout *timeout) /** * 获取定时器还剩多长时间超时 */ int uloop_timeout_remaining(struct uloop_timeout *timeout) 进程事件
/** * 注册新进程到事件处理循环 */
int uloop_process_add(struct uloop_process *p) /** * 从事件处理循环中销毁指定进程 */ int uloop_process_delete(struct uloop_process *p) 数据结构
描述符
struct uloop_fd {
uloop_fd_handler cb; /** 文件描述符，调用者初始化 */
int fd; /** 文件描述符，调用者初始化 */
bool eof;
bool error;
bool registered; /** 是否已注册到uloop中 */
uint8_t flags;
};
定时器
struct uloop_timeout {
struct list_head list;
bool pending;
uloop_timeout_handler cb; /** 文件描述符， 调用者初始化 */
struct timeval time; /** 文件描述符， 调用者初始化 */
};
进程
struct uloop_process {
struct list_head list;
bool pending;
uloop_process_handler cb; /** 文件描述符， 调用者初始化 */
pid_t pid; /** 文件描述符， 调用者初始化 */
};
事件回调函数
描述符
typedef void (*uloop_fd_handler)(struct uloop_fd *u, unsigned int events)
定时器
typedef void (*uloop_timeout_handler)(struct uloop_timeout *t)
进程
typedef void (*uloop_process_handler)(struct uloop_process *c, int ret)
事件标志
#define ULOOP_READ (1 << 0)
#define ULOOP_WRITE (1 << 1)
#define ULOOP_EDGE_TRIGGER (1 << 2)
#define ULOOP_BLOCKING (1 << 3)
#define ULOOP_EVENT_MASK (ULOOP_READ | ULOOP_WRITE)
任务队列(runqueue.c/h)
任务队列是通过uloop定时器实现，把定时器超时时间设置为1，通过uloop事件循环来处理定时器就会处理任务队列中的task。进程任务在任务队列基本上实现，加入子进程退出监控
数据结构
struct runqueue {
struct safe_list tasks_active; /** 活动任务队列 */
struct safe_list tasks_inactive; /** 不活动任务队列 */
struct uloop_timeout timeout;
int running_tasks; /** 当前活动任务数目 */
int max_running_tasks; /** 允许最大活动任务数目 */
bool stopped; /** 是否停止任务队列 */
bool empty; /** 任务队列(包括活动和不活动)是否为空 */
/* called when the runqueue is emptied */
void (*empty_cb)(struct runqueue *q);
};
struct runqueue_task_type {
const char *name;
/* * called when a task is requested to run * * The task is removed from the list before this callback is run. It * can re-arm itself using runqueue_task_add. */
void (*run)(struct runqueue *q, struct runqueue_task *t);
/* * called to request cancelling a task * * int type is used as an optional hint for the method to be used when * cancelling the task, e.g. a signal number for processes. Calls * runqueue_task_complete when done. */
void (*cancel)(struct runqueue *q, struct runqueue_task *t, int type);
/* * called to kill a task. must not make any calls to runqueue_task_complete, * it has already been removed from the list. */
void (*kill)(struct runqueue *q, struct runqueue_task *t);
};
struct runqueue_task {
struct safe_list list;
const struct runqueue_task_type *type;
struct runqueue *q;
void (*complete)(struct runqueue *q, struct runqueue_task *t);
struct uloop_timeout timeout;
int run_timeout; /** >0表示规定此任务执行只有run_timeout毫秒 */
int cancel_timeout; /** >0表示规则任务延取消操作执行只有run_timeout毫秒*/
int cancel_type;
bool queued; /** 此任务是否已加入任务队列中 */
bool running; /** 此任务是否活动，即已在活动队列中 */
bool cancelled; /** 此任务是否已被取消 */
};
struct runqueue_process {
struct runqueue_task task;
struct uloop_process proc;
};
接口说明
任务队列
/** * 初始化任务队列 */
void runqueue_init(struct runqueue *q) /** * 取消所有任务队列 */ void runqueue_cancel(struct runqueue *q);
/** * 取消活动中的任务 */
void runqueue_cancel_active(struct runqueue *q);
/** * 取消不活动的任务 */
void runqueue_cancel_pending(struct runqueue *q);
/** * 杀死所有任务 */
void runqueue_kill(struct runqueue *q);
/** * 停止所有任务 */
void runqueue_stop(struct runqueue *q);
/** * 重新开始任务 */
void runqueue_resume(struct runqueue *q);
任务操作
/** * 添加新任务到队列尾 * * @running true-加入活动队列；false-加入不活动队列 */
void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running);
/** * 添加新任务到队列头 * * @running true-加入活动队列；false-加入不活动队列 */
void runqueue_task_add_first(struct runqueue *q, struct runqueue_task *t, bool running);
/** * 完全任务 */
void runqueue_task_complete(struct runqueue_task *t);
/** * 取消任务 */
void runqueue_task_cancel(struct runqueue_task *t, int type);
/** * 杀死任务 */
void runqueue_task_kill(struct runqueue_task *t);
进程任务
void runqueue_process_add(struct runqueue *q, struct runqueue_process *p, pid_t pid);
/** * to be used only from runqueue_process callbacks */
void runqueue_process_cancel_cb(struct runqueue *q, struct runqueue_task *t, int type);
void runqueue_process_kill_cb(struct runqueue *q, struct runqueue_task *t);
流缓冲管理(ustream.c/h/ustream-fd.c)
数据结构
struct ustream_buf {
struct ustream_buf *next;
char *data; /** 指向上次操作buff开始地址 */
char *tail; /** 指向未使用buff开始地址 */
char *end; /** 指向buf结束地址 */
char head[]; /** 指向buf开始地址 */
};
struct ustream_buf_list {
struct ustream_buf *head; /** 指向第1块ustream_buf */
struct ustream_buf *data_tail; /** 指向未使用的ustream_buf */
struct ustream_buf *tail; /** 指向最后的ustream_buf */
int (*alloc)(struct ustream *s, struct ustream_buf_list *l);
int data_bytes; /** 已用存储空间大小 */
int min_buffers; /** 可存储最小的ustream_buf块个数 */
int max_buffers; /** 可存储最大的ustream_buf块个数 */
int buffer_len; /** 每块ustream_buf块存储空间大小 */
int buffers; /** ustream_buf块个数 */
};
struct ustream {
struct ustream_buf_list r, w;
struct uloop_timeout state_change;
struct ustream *next;
/* * notify_read: (optional) * called by the ustream core to notify that new data is available * for reading. * must not free the ustream from this callback */
void (*notify_read)(struct ustream *s, int bytes_new);
/* * notify_write: (optional) * called by the ustream core to notify that some buffered data has * been written to the stream. * must not free the ustream from this callback */
void (*notify_write)(struct ustream *s, int bytes);
/* * notify_state: (optional) * called by the ustream implementation to notify that the read * side of the stream is closed (eof is set) or there was a write * error (write_error is set). * will be called again after the write buffer has been emptied when * the read side has hit EOF. */
void (*notify_state)(struct ustream *s);
/* * write: * must be defined by ustream implementation, accepts new write data. * 'more' is used to indicate that a subsequent call will provide more * data (useful for aggregating writes) * returns the number of bytes accepted, or -1 if no more writes can * be accepted (link error) */
int (*write)(struct ustream *s, const char *buf, int len, bool more);
/* * free: (optional) * defined by ustream implementation, tears down the ustream and frees data */
void (*free)(struct ustream *s);
/* * set_read_blocked: (optional) * defined by ustream implementation, called when the read_blocked flag * changes */
void (*set_read_blocked)(struct ustream *s);
/* * poll: (optional) * defined by the upstream implementation, called to request polling for * available data. * returns true if data was fetched. */
bool (*poll)(struct ustream *s);
/* * ustream user should set this if the input stream is expected * to contain string data. the core will keep all data 0-terminated. */
bool string_data; /** 此ustream是否为字符串，true-是；false-否 */
bool write_error; /** 写出错，true-是；false-否 */
bool eof, eof_write_done;
enum read_blocked_reason read_blocked;
};
struct ustream_fd {
struct ustream stream;
struct uloop_fd fd;
};
存储结构
接口说明
初始/销毁
/** * ustream_fd_init: create a file descriptor ustream (uses uloop) */
void ustream_fd_init(struct ustream_fd *s, int fd) /** * ustream_init_defaults: fill default callbacks and options */ void ustream_init_defaults(struct ustream *s) /** * ustream_free: free all buffers and data associated with a ustream */ void ustream_free(struct ustream *s) 写入read buffer
/* * ustream_reserve: allocate rx buffer space * 分配len大小的read buffer可用内存空间，与ustream_fill_read()配合使用 * * len: hint for how much space is needed (not guaranteed to be met) * maxlen: pointer to where the actual buffer size is going to be stored */
char *ustream_reserve(struct ustream *s, int len, int *maxlen)
/** * ustream_fill_read: mark rx buffer space as filled * 设置被ustream_reseve()分配read buffer后写入的数据大小， * 回调notify_read()接口，表示有数据可读 */
void ustream_fill_read(struct ustream *s, int len) 读出read buffer
一般在notify_read()回调接口使用
/* * ustream_get_read_buf: get a pointer to the next read buffer data * 获取新一次写入的内容，与ustream_consume()配置使用 */
char *ustream_get_read_buf(struct ustream *s, int *buflen)
/** * ustream_consume: remove data from the head of the read buffer */
void ustream_consume(struct ustream *s, int len) 操作write buffer
尽最大能力调用write()回调用接口写入，如果超出能力将把未写入的数据存储在write buffer中
/* * ustream_write: add data to the write buffer */
int ustream_write(struct ustream *s, const char *buf, int len, bool more) int ustream_printf(struct ustream *s, const char *format, ...) int ustream_vprintf(struct ustream *s, const char *format, va_list arg) 把在write buffer中的数据写入实际地方，调用write()回调接口和notify_write()回调接口。一般在描述符的poll操作中调用，表示当描述符变为可写时立即把上一次未写入的内容进行写入操作。
/*
* ustream_write_pending: attempt to write more data from write buffers
* returns true if all write buffers have been emptied.
*/ bool ustream_write_pending(struct ustream *s) 例子
进程任务队列
初始化:
static struct runqueue q;
static void q_empty(struct runnqueue *q) {
}
static void task_init(void) {
runqueue_init(&q);
q.empty_cb = q_empty;
q.max_running_tasks = 1; /** 每次只能执行一个任务 */
}
定义任务:
struct task {
struct runqueue_process proc;
char arg[128];
};
static void task_run(struct runqueue *q, struct runqueue_task *t) {
struct task *tk = container_of(t, struct task, proc.task);
pid_t pid;
pid = fork();
if (pid < 0)
return;
if (pid) {
/** * 因为此task正在运行，实际上只是把此task子进程加入到 * 进程监听uloop中，当此task子进程运行完成时回调自定义接口， * 并执行一个任务循环 「runqueue_start_next」 */
runqueue_process_add(q, &tk->proc, pid);
return;
}
/** 子进程使用sleep命令代替 */
execlp("sleep", "sleep", tk->arg, NULL);
exit(1);
}
struct const struct runqueue_task_type task_type = {
.run = task_run, /** 需要实现 */
.cancel = runqueue_process_cancel_cb, /** 自带接口 */
.kill = runqueue_process_kill_cb, /** 自带接口 */
};
添加任务:
static void task_complete(struct runqueue *q, struct runqueue_task *t) {
struct task *tk = container_of(t, struct task, proc.task);
free(tk);
}
void task_add(char *arg) {
struct task *tk;
tk = calloc(1, sizeof(struct task));
tk->proc.task.type = &task_type; /** 指定任务类型 */
tk->proc.task.complete = task_complete; /** 任务执行完成后hook接口 */
tk->proc.task.run_timeout = timeout; /** 任务执行超时时间 */
strcpy(tk->arg, arg);
/** 加入到任务队列中 */
runqueue_task_add(&q, &tk->proc.task, false);
}