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发信人: GyeaonWoo (柏林恋人), 信区: Linux
标 题: Linus's Linux--fs/open.c
发信站: 荔园晨风BBS站 (Mon Aug 25 20:03:22 2003), 站内信件
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <utime.h>
#include <sys/stat.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/kernel.h>
#include <asm/segment.h>
int sys_utime(char * filename, struct utimbuf * times)
{
struct m_inode * inode;
long actime,modtime;
if (!(inode=namei(filename)))
return -ENOENT;
if (times) {
actime = get_fs_long((unsigned long *) ×->actime);
modtime = get_fs_long((unsigned long *) ×->modtime);
} else
actime = modtime = CURRENT_TIME;
inode->i_atime = actime;
inode->i_mtime = modtime;
inode->i_dirt = 1;
iput(inode);
return 0;
}
int sys_access(const char * filename,int mode)
{
struct m_inode * inode;
int res;
mode &= 0007;
if (!(inode=namei(filename)))
return -EACCES;
res = inode->i_mode & 0777;
iput(inode);
if (!(current->euid && current->uid))
if (res & 0111)
res = 0777;
else
res = 0666;
if (current->euid == inode->i_uid)
res >>= 6;
else if (current->egid == inode->i_gid)
res >>= 6;
if ((res & 0007 & mode) == mode)
return 0;
return -EACCES;
}
int sys_chdir(const char * filename)
{
struct m_inode * inode;
if (!(inode = namei(filename)))
return -ENOENT;
if (!S_ISDIR(inode->i_mode)) {
iput(inode);
return -ENOTDIR;
}
iput(current->pwd);
current->pwd = inode;
return (0);
}
int sys_chroot(const char * filename)
{
struct m_inode * inode;
if (!(inode=namei(filename)))
return -ENOENT;
if (!S_ISDIR(inode->i_mode)) {
iput(inode);
return -ENOTDIR;
}
iput(current->root);
current->root = inode;
return (0);
}
int sys_chmod(const char * filename,int mode)
{
struct m_inode * inode;
if (!(inode=namei(filename)))
return -ENOENT;
if (current->uid && current->euid)
if (current->uid!=inode->i_uid && current->euid!=inode->i_uid) {
iput(inode);
return -EACCES;
} else
mode = (mode & 0777) | (inode->i_mode & 07000);
inode->i_mode = (mode & 07777) | (inode->i_mode & ~07777);
inode->i_dirt = 1;
iput(inode);
return 0;
}
int sys_chown(const char * filename,int uid,int gid)
{
struct m_inode * inode;
if (!(inode=namei(filename)))
return -ENOENT;
if (current->uid && current->euid) {
iput(inode);
return -EACCES;
}
inode->i_uid=uid;
inode->i_gid=gid;
inode->i_dirt=1;
iput(inode);
return 0;
}
int sys_open(const char * filename,int flag,int mode)
{
struct m_inode * inode;
struct file * f;
int i,fd;
mode &= 0777 & ~current->umask;
for(fd=0 ; fd<NR_OPEN ; fd++)
if (!current->filp[fd])
break;
if (fd>=NR_OPEN)
return -EINVAL;
current->close_on_exec &= ~(1<<fd);
f=0+file_table;
for (i=0 ; i<NR_FILE ; i++,f++)
if (!f->f_count) break;
if (i>=NR_FILE)
return -EINVAL;
(current->filp[fd]=f)->f_count++;
if ((i=open_namei(filename,flag,mode,&inode))<0) {
current->filp[fd]=NULL;
f->f_count=0;
return i;
}
/* ttys are somewhat special (ttyxx major==4, tty major==5) */
if (S_ISCHR(inode->i_mode))
if (MAJOR(inode->i_zone[0])==4) {
if (current->leader && current->tty<0) {
current->tty = MINOR(inode->i_zone[0]);
tty_table[current->tty].pgrp = current->pgrp;
}
} else if (MAJOR(inode->i_zone[0])==5)
if (current->tty<0) {
iput(inode);
current->filp[fd]=NULL;
f->f_count=0;
return -EPERM;
}
f->f_mode = inode->i_mode;
f->f_flags = flag;
f->f_count = 1;
f->f_inode = inode;
f->f_pos = 0;
return (fd);
}
int sys_creat(const char * pathname, int mode)
{
return sys_open(pathname, O_CREAT | O_TRUNC, mode);
}
int sys_close(unsigned int fd)
{
struct file * filp;
if (fd >= NR_OPEN)
return -EINVAL;
current->close_on_exec &= ~(1<<fd);
if (!(filp = current->filp[fd]))
return -EINVAL;
current->filp[fd] = NULL;
if (filp->f_count == 0)
panic("Close: file count is 0");
if (--filp->f_count)
return (0);
iput(filp->f_inode);
return (0);
}
--
一个疯子的四大症状:
一、崇拜悲剧的力量,爱慕美狄亚
二、痛苦的时候不是发呆就是讲费话
三、看到有人在赞美肉麻就要发狂
四、像夸大自己的优点那样夸大自己的缺点活着就像皮影戏,一撤了幕,就什么都没了。
※ 来源:·荔园晨风BBS站 bbs.szu.edu.cn·[FROM: 192.168.35.5]
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