poll code

descriptors is relatively small, or when it is relatively large, the stack will be used for storage for the first timeIf (! Stack_pp)Stack_pp = pp = (struct poll_list *) stack_pps;Else {Pp = kmalloc (size, gfp_kernel );If (! Pp)Goto out_fds;}PP-> next = NULL;PP-> Len = num;If (Head = NULL)Head = pp;ElseWalk-> next = pp; Walk = pp;If (copy_from_user (PP-> entries, ufds + NFDs-I,Sizeof (struct pollfd) * num )){Err =-efault;Goto out_fds;}I-= PP-> Len;} // Real

connection is established The descriptor has an error, and returns 1 if the call to the read system calls the reading socket. is considered writable when the following happens: The number of bytes in the socket's send buffer is greater than the Low-water Mark property value of the socket's send buffer and the socket is connected or does not require a connection (such as UDP). Write half connection closed, calling the Write function will produce sigpipe The descriptor h

In fact, these functions call the do_one function, which is used to obtain the complete port status. All timers and network events are scheduled through do_one, do_one function prototype: size_t do_one(bool block, boost::system::error_code ec) Its first parameter indicates whether it is blocked, in the do_one code: BOOL ok = ::GetQueuedCompletionStatus(iocp_.handle, bytes_transferred, completion_key, overlapped, block ? timeout : 0); If it is false,

The publishing page is only available when the user is logged in, so check that you are logged in and then allow the poll to be issued. Note: Once published will not be modified! The information entered by the user is posted to the background in post format. = $min $vname = "") {for ($i =1; $i 1. Check if login $ouser =@$_get[' user ']; if ($ouser! = ") {2. Get the current time $time =time (); $st

Release date:Updated on: 2012-10-02 Affected Systems:Joomla! JE Poll 1.0Unaffected system:Joomla! JE Poll 1.1Description:--------------------------------------------------------------------------------Bugtraq id: 51229CVE (CAN) ID: CVE-2012-5101 Joomla! Is an Open Source Content Management System (CMS ). Joomla! JE Poll is a component, module, and plug-in of Jo

Release date:Updated on: 2013-02-03 Affected Systems:WordPress Poll Plugin 34.xDescription:--------------------------------------------------------------------------------Bugtraq id: 57630The WordPress Poll plug-in is a fully interactive voting system that supports single choice and multiple choice.WordPress Poll 34.05 and earlier versions do not correctly verify

Some processes require the ability to inform the kernel beforehand, so that once the kernel discovers that one or more of the I/O conditions specified by the process are ready (that is, the input is ready to be read, or the descriptor is able to withstand more output), he notifies the process that this capability is called I/O multiplexing1.IO Models5 Basic I/O models阻塞式I/O非阻塞式I/OI/O复用(select和poll)信号驱动式I/O(SIGIO)异步I/OAn input operation typically consi

structure is the core of the character device driver * When an application operates a device file, the function called open, read, write, and so on, will eventually call the corresponding function in the structure.static struct File_operations Key_poll_dev_fops = {. Owner = This_module,/ * This is a macro that points to the __this_module variable created automatically when the module is compiled * /. open = Key_poll_dev_open,. Release = Key_poll_dev_close,. Read = Key_poll_dev_read,.

AIX supports poll, tests it, and matches expectations. Server #include #include #include #include #include #include #include /*Pollin Date can be readPollrdnorm Date can be read Pollrdband Priority date can be read Pollpri Urgent date can be read Pollout Date can be writePollwrnorm Date can be write Pollwrband Priority date can be write Pollmsg used by Sigpoll Poller Error Pollhup Descriptor Hup Up Pollnval Descriptor Illegal */int main (int argc,

poll mechanism function: the equivalent of a timer, the time has not yet the resources to wake up the process.The main purpose is: The process is set up for a period of time to wait for resources, if the time to the resource has not arrived, the process immediately from the sleep state wake up no longer waiting. Of course, this is only a situation where resources are useless for the process after that time.The implementation process of the

Transferred from: http://blog.csdn.net/yikai2009/article/details/8653842Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.Directory (?) [-] Select-System call int SELECT-function Function Parameters return value Select-System invoke-how to use 1 adding files to the file descriptor set to be monitored 2 call Select to start monitoring 3 Determine if the file has changed Four

, button_waitq, wait );ReturnIsempty ()? 0: Pollin | pollrdnorm;}Static const struct file_operations buttons_fops = {. Owner = this_module,. Read = buttons_read,. Open = buttons_open,/* set the pin and apply for resources */. Release = buttons_close,. Poll = buttons_poll,};Int buttons_init (void){Int I;Major = register_chrdev (0, "buttons", buttons_fops );/* Sysfs => mount to/sys */CLS = class_create (this_module, "buttons_class ");Class_device_crea

Functions of the select () functionThe system calls the back-end Implementation of select and poll, and uses these two system calls to query whether the device can read or write, or whether it is in a certain state. If poll is empty, the driver is considered readable and writable. The returned value is a status mask.How to Use the select () function?The Select () function interface is mainly based on the 'f

First, the phenomenon 1. See if a process exists Ps-ef | Grep-v ' grep ' |grep-e ' Shell/cron/bonus/cash ' www 2624 1 0 Oct24? 00:00:35/usr/local/bin/php/data1/www/htdocs/hb.e.weibo.com/v2/www/htdocs/index.php--uri=shell/cron/bonus/cash- -get=proc_num=1proc_total=1--post= 2. View process creation time Ps-p 2624-o Lstart Started Sat OCT 24 22:20:03 2015 3. View system calls to the process Strace-p 2624 Process 2624 Attached-interrupt to quit Restart_syscall (... resuming interrupted call ...>)

Let's first introduce nginx:Supports high-concurrency connections. the official test shows 5 W concurrent connections, but 2-4 W concurrent connections can be made in actual production, thanks to nginx's use of the latest epoll (Linux 2.6 kernel) and kqueue (FreeBSD) network I/O models. apache uses the traditional select model. Its stable prefork mode is a multi-process model, which requires frequent distribution of child processes, and consumes more CPU and other server resources than nginx.

Select and poll FunctionsIn the previous chapter, we encountered a problem that the client was blocked from reading data from the standard input. At the same time, the server required to close the connection for some reason and sent a fin to the client, the client can only know that the connection is closed after reading the data from the standard input. I/O reuse introduced in this chapter can solve this problem well. 1. i/O model. in UNIX, there are

); }View CodeAdvantages: Simple implementation, high execution efficiency, good compatibility, and when the descriptor set is active, performance may be better than epoll.A few of the major drawbacks of select:(1) Each call to select, the FD collection needs to be copied from the user state to the kernel state, the cost of FD is very large(2) At the same time, each call to select requires a kernel traversal of all the FD passed in, which is also very expensive when FD is very large(3) The number

Many software comes with cutting logs, such as Tomcat, which can be named by time. Rsyslog can generate files by date, but does not support "% $year%-% $month%-% $day%" These variables to read the file (current version number: rsyslog-8.17.0-1.el6.x86_64).Then, you need to use the log polling logrotate. overview, configuration.Global configuration:/etc/logrotate.confLocal configuration:/etc/logrotate.d/for ease of administration, custom configurations are put into/etc/logrotate.d/ U

nginx Log poll cutBy default, Nginx will generate all the access logs into a specified access log file Access*.log, but in this way, a long time will lead to log a single file is very large, not conducive to the analysis and processing of logs, it is necessary to the Nginx log by day or by the hour, etc. Specific to see the specific online business, so that it is divided into different files to save. Here we are cutting logs by day.1. Configure the lo

In fact, this can only be considered a summary, a review of the takeaway. "Ranking algorithm based on user voting" series, Author: Nanyi. This series of articles is indeed beautifully written, layered and thoughtful. Author blog:http://www.ruanyifeng.com/blog/ 1. Only the number of votes in the affirmative (1) per unit time is ranked delicious. Implementation: hourly statistics times, high in the front. Advantages: Simple, it does reflect the heat. Cons: not smooth enough; popular content may ha