[Unit]
After=network.service

[Service]
Type=forking
ExecStart=/usr/local/bin/mystart.sh

[Install]
WantedBy=default.target

#!/bin/bash
echo 'my start script start to run'


echo 'my start script run done'

exit 0

The Silver Searcher is like grep or ack, except faster. It's written in super-optimized C (like grep) and it's intelligent about entirely skipping files that you don't want to waste time searching (like ack).

ag源码
https://github.com/ggreer/the_silver_searcher

ag非官方下载地址

https://blog.kowalczyk.info/software/the-silver-searcher-for-windows.html

https://github.com/k-takata/the_silver_searcher-win32

2020/10/26 01:01:33 tcp:127.0.0.1:50610 accepted tcp:beacons.gcp.gvt2.com:443 [proxy] 
2020/10/26 01:01:35 [Warning] failed to handler mux client connection > v2ray.com/core/proxy/vmess/outbound: connection ends > v2ray.com/core/proxy/vmess/outbound: failed to read header > v2ray.com/core/proxy/vmess/encoding: failed to read response header > websocket: close 1000 (normal)

#!/bin/ash


domain='xxxx'
subDomain='xxxx'
recordId='xxxx'

sId='xxxx'
sKey='xxxx'
#
# Get record list first, then find out record id whatever you want to update
#
function get_record_list()
{

        signatureMethod='HmacSHA1'
        timestamp=`date +%s`
        nonce=`head -200 /dev/urandom | gnu-cksum | cut -f2 -d" "`
        region=bj
        url="https://cns.api.qcloud.com/v2/index.php"
        action='RecordList'

        src=`printf "GETcns.api.qcloud.com/v2/index.php?Action=%s&Nonce=%s&Region=%s&SecretId=%s&SignatureMethod=%s&Timestamp=%s&domain=%s" $action $nonce $region $sId $signatureMethod $timestamp $domain`


        signature=`echo -n $src|openssl dgst -sha1 -hmac $sKey -binary |base64`

        params=`printf "Action=%s&domain=%s&Nonce=%s&Region=%s&SecretId=%s&Signature=%s&SignatureMethod=%s&Timestamp=%s" $action $domain $nonce $region $sId "$signature" $signatureMethod $timestamp `


        curl -G -s -d "$params" --data-urlencode "Signature=$signature" "$url"
}
#
# $1 ipv6
# You provide a new ipv6 address to update your subDomain record
#
function modify_record()
{
        signatureMethod='HmacSHA1'

        timestamp=`date +%s`
        nonce=`head -200 /dev/urandom | cksum | cut -f2 -d" "`
        region=bj

        url="https://cns.api.qcloud.com/v2/index.php"
        #设置新ipv6
        action='RecordModify'
        recordType='AAAA'
        recordLine='默认'

        value=$1

        timestamp=`date +%s`
        nonce=`head -200 /dev/urandom | cksum | cut -f2 -d" "`

        src=`printf "GETcns.api.qcloud.com/v2/index.php?Action=%s&Nonce=%s&Region=%s&SecretId=%s&SignatureMethod=%s&Timestamp=%s&domain=%s&recordId=%s&recordLine=%s&recordType=%s&subDomain=%s&value=%s" $action $nonce $region $sId $signatureMethod $timestamp $domain $recordId $recordLine $recordType $subDomain $value`

        signature=`echo -n $src|openssl dgst -sha1 -hmac $sKey -binary |base64`

        params=`printf "Action=%s&Nonce=%s&Region=%s&SecretId=%s&SignatureMethod=%s&Timestamp=%s&domain=%s&recordId=%s&recordLine=%s&recordType=%s&subDomain=%s&value=%s" $action $nonce $region $sId $signatureMethod $timestamp $domain $recordId $recordLine $recordType $subDomain $value`

        result=`curl -G  -s -d "$params" --data-urlencode "Signature=$signature" "$url"`
        echo $result
}

#
#
# we only get the first ipv6 address that owned by interface
#
get_ipv6()
{
        ret=`ip a  | grep 2409 | tail -n1 | awk '{print $2}' | awk -F'/' '{print $1}'`
        echo $ret
}

#
# Main Entry
#
ipv6=$(get_ipv6)
echo "Assign $ipv6 to xxxx"

modify_record "$ipv6"

root@OpenWrt:~# crontab -l
*/5 * * * * /root/ddns.sh

controller/ytdownloader.php
$this->YTDLBinary = '/usr/local/bin/youtube-dl'; // default path

apt install python-pip
pip install youtube-dl

Note that the DMA API works with any bus independent of the underlying
microprocessor architecture. You should use the DMA API rather than the
bus-specific DMA API, i.e., use the dma_map_*() interfaces rather than the
pci_map_*() interfaces.

#include <linux/dma-mapping.h>
dma_addr_t addr;

desc->word0=address;
wmb();
desc->word1=DESC_VALID;

https://discourse.coreelec.org/t/solved-sound-volume-via-hdmi-suddenly-very-low/6045/4

A couple of things that might help.

One, plug a keyboard in and press the + key a few times. kodi’s volume indicator should popup to centre of the screen. It’s possible that kodi’s internal sound level ended up turned down some how. Use + and - keys to adjust volume level if this is the case.

Two, check the audio device that you are using, Settings/System/Audio. Try changing it to one that mentions hdmi at the end of it. If it is not already on that one.

The +/- did the trick. Tbh, I didn’t even know Kodi had that key shortcuts.
In all the years I’ve been using Kodi on several platforms, I’ve always used CEC.

For some reason the volume was at one third. Putting it back to 100% and volume was back to normal (for me).

Thanks for the replies!

struct inet_connection_sock {
	struct inet_sock {
		struct sock {
			struct timer_list	sk_timer; //(1) keepalive timer
		}
	}
 	struct timer_list	  icsk_retransmit_timer; //(2) time out timer
 	struct timer_list	  icsk_delack_timer; //(3) delay ack timer
}

static void tcp_keepalive_timer (struct timer_list *t)
	...
	if (elapsed >= keepalive_time_when(tp)) { // 7200s
			/* If the TCP_USER_TIMEOUT option is enabled, use that
			 * to determine when to timeout instead.
			 */
			if ((icsk->icsk_user_timeout != 0 &&
				elapsed >= msecs_to_jiffies(icsk->icsk_user_timeout) &&
				icsk->icsk_probes_out > 0) ||
				(icsk->icsk_user_timeout == 0 &&
				icsk->icsk_probes_out >= keepalive_probes(tp))) { //到达次数限制9
					tcp_send_active_reset(sk, GFP_ATOMIC);
					tcp_write_err(sk);
					goto out;
			}
			if (tcp_write_wakeup(sk, LINUX_MIB_TCPKEEPALIVE) <= 0) { //发送probe报文
					icsk->icsk_probes_out++;
					elapsed = keepalive_intvl_when(tp);// 75s
			} else {
					/* If keepalive was lost due to local congestion,
					 * try harder.
					 */
					elapsed = TCP_RESOURCE_PROBE_INTERVAL;
			}
	} else {
			/* It is tp->rcv_tstamp + keepalive_time_when(tp) */
			elapsed = keepalive_time_when(tp) - elapsed;
	}
	...

net.ipv4.tcp_keepalive_probes = 9

static void tcp_ack_probe(struct sock *sk)
{
        struct inet_connection_sock *icsk = inet_csk(sk);
        struct sk_buff *head = tcp_send_head(sk);
        const struct tcp_sock *tp = tcp_sk(sk);

        /* Was it a usable window open? */
        if (!head)
                return;
        if (!after(TCP_SKB_CB(head)->end_seq, tcp_wnd_end(tp))) { // normal window size
                icsk->icsk_backoff = 0;
                inet_csk_clear_xmit_timer(sk, ICSK_TIME_PROBE0);
                /* Socket must be waked up by subsequent tcp_data_snd_check().
                 * This function is not for random using!
                 */
        } else { // zero-window-size
                unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX);

                tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,
                                     when, TCP_RTO_MAX, NULL);
        }
}

net.ipv4.tcp_retries2 = 15

root@ubuntu:/share/linux# find . -name Kconfig | xargs grep -rsn VMAP_STACK
./arch/Kconfig:821:config HAVE_ARCH_VMAP_STACK
./arch/Kconfig:841:config VMAP_STACK
./arch/Kconfig:844:     depends on HAVE_ARCH_VMAP_STACK
./arch/arm64/Kconfig:135:       select HAVE_ARCH_VMAP_STACK
./arch/s390/Kconfig:133:        select HAVE_ARCH_VMAP_STACK
./arch/s390/Kconfig:714:        depends on !VMAP_STACK
./arch/x86/Kconfig:152: select HAVE_ARCH_VMAP_STACK             if X86_64

static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
{
#ifdef CONFIG_VMAP_STACK
        void *stack;
        int i;

        for (i = 0; i < NR_CACHED_STACKS; i++) {
                struct vm_struct *s;

                s = this_cpu_xchg(cached_stacks[i], NULL);

                if (!s)
                        continue;

                /* Clear the KASAN shadow of the stack. */
                kasan_unpoison_shadow(s->addr, THREAD_SIZE);

                /* Clear stale pointers from reused stack. */
                memset(s->addr, 0, THREAD_SIZE);


                tsk->stack_vm_area = s;
                tsk->stack = s->addr;
                return s->addr;
        }

        /*
         * Allocated stacks are cached and later reused by new threads,
         * so memcg accounting is performed manually on assigning/releasing
         * stacks to tasks. Drop __GFP_ACCOUNT.
         */
        stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
                                     VMALLOC_START, VMALLOC_END,
                                     THREADINFO_GFP & ~__GFP_ACCOUNT,
                                     PAGE_KERNEL,
                                     0, node, __builtin_return_address(0));
        /*
         * We can't call find_vm_area() in interrupt context, and
         * free_thread_stack() can be called in interrupt context,
         * so cache the vm_struct.
         */
        if (stack) {
                tsk->stack_vm_area = find_vm_area(stack);
                tsk->stack = stack;
        }
        return stack;

#else
        struct page *page = alloc_pages_node(node, THREADINFO_GFP,
                                             THREAD_SIZE_ORDER);

        if (likely(page)) {
                tsk->stack = page_address(page);
                return tsk->stack;
        }
        return NULL;
#endif
}

#define THREAD_SIZE_ORDER       1
#define THREAD_SIZE             (PAGE_SIZE << THREAD_SIZE_ORDER)

#ifdef CONFIG_KASAN
#define KASAN_STACK_ORDER 1
#else
#define KASAN_STACK_ORDER 0
#endif

#define THREAD_SIZE_ORDER       (2 + KASAN_STACK_ORDER)
#define THREAD_SIZE  (PAGE_SIZE << THREAD_SIZE_ORDER)

$ cat arch/x86/Kconfig
config X86
        def_bool y
		...
		select THREAD_INFO_IN_TASK
		...

$ cat include/linux/sched.h
struct task_struct {
#ifdef CONFIG_THREAD_INFO_IN_TASK
        /*
         * For reasons of header soup (see current_thread_info()), this
         * must be the first element of task_struct.
         */
        struct thread_info              thread_info;
#endif

high address                low address 
|----------------------|<-------->|
                        thread_info

struct scatterlist {
        unsigned long   page_link;
        unsigned int    offset;
        unsigned int    length;
        dma_addr_t      dma_address;
#ifdef CONFIG_NEED_SG_DMA_LENGTH
        unsigned int    dma_length;
#endif
};

         vmalloc buffer
          |-------------|
|-------------|-----------|
        pageX	       pageY

$ cat net/sunrpc/auth_gss/gss_krb5_crypto.c
u32
krb5_encrypt(
        struct crypto_sync_skcipher *tfm,
        void * iv,
        void * in,
        void * out,
        int length)
{
        u32 ret = -EINVAL;
        struct scatterlist sg[1];
		...
		memcpy(out, in, length);
        sg_init_one(sg, out, length);
		...
}
$ cat lib/scatterlist.c
void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen)
{
        sg_init_table(sg, 1);
        sg_set_buf(sg, buf, buflen);
}
$ cat include/linux/scatterlist.h
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
			      unsigned int buflen)
{
#ifdef CONFIG_DEBUG_SG
	BUG_ON(!virt_addr_valid(buf));
#endif
	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}
$ cat include/linux/scatterlist.h
static inline void sg_set_page(struct scatterlist *sg, struct page *page,
			       unsigned int len, unsigned int offset)
{
	sg_assign_page(sg, page);
	sg->offset = offset;
	sg->length = len;
}