Linux内核网络协议栈2－socket从库函数到内核

diecui1202

 
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一、socket()库函数到系统调用，再到内核

<div style="background-color: transparent; margin-top: 0px; margin-left: 0px; margin-bottom: 0px; margin-right: 0px;">1、Linux运行的C库是glibc；
2、socket()调用如下：
1) socket()->__socket()：glibc-2.3.6/sysdept/generic/socket.c (weak_alias(name1, name2))
2) __socket()：glibc-2.3.6/sysdept/unix/sysv/linux/i386/socket.S
3) ENTER_KERNEL：
movl $SYS_ify(socketcall), %eax/* System call number in %eax.  *//* Use ## so `socket' is a separate token that might be #define'd.  */movl $P(SOCKOP_,socket), %ebx/* Subcode is first arg to syscall.  */lea 4(%esp), %ecx/* Address of args is 2nd arg.  */        /* Do the system call trap.  */ENTER_KERNEL这里，
SYS_ify宏定义为：glibc-2.3.6/sysdept/unix/sysv/linux/i386/Sysdept.h