checkpoint - simpler namei interface
This commit is contained in:
rsc
parent
ef30c2c749
commit
e2a620da49
4 changed files with 136 additions and 122 deletions
6
defs.h
6
defs.h
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@ -128,12 +128,14 @@ void itrunc(struct inode*);
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void idecref(struct inode*);
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struct inode* iincref(struct inode*);
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void iput(struct inode*);
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struct inode* namei(char*, int, uint*, char**, struct inode**);
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struct inode* namei(char*);
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struct inode* nameiparent(char*, char**, int*);
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void stati(struct inode*, struct stat*);
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int readi(struct inode*, char*, uint, uint);
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int writei(struct inode*, char*, uint, uint);
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struct inode* mknod(char*, short, short, short);
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struct inode* mknod1(struct inode*, char*, short, short, short);
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struct inode* dircreat(struct inode*, char*, int, short, short, short);
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int dirlookup(struct inode*, char*, int, uint*, uint*);
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int unlink(char*);
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void iupdate(struct inode*);
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int link(char*, char*);
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172
fs.c
172
fs.c
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@ -465,7 +465,7 @@ writei(struct inode *ip, char *src, uint off, uint n)
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// set *poff to the byte offset of the directory entry
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// set *pinum to the inode number
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// return 0.
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static int
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int
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dirlookup(struct inode *dp, char *name, int namelen, uint *poff, uint *pinum)
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{
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uint off;
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@ -485,8 +485,10 @@ dirlookup(struct inode *dp, char *name, int namelen, uint *poff, uint *pinum)
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if(memcmp(name, de->name, namelen) == 0 &&
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(namelen == DIRSIZ || de->name[namelen]== 0)){
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// entry matches path element
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*poff = off + (uchar*)de - bp->data;
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*pinum = de->inum;
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if(poff)
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*poff = off + (uchar*)de - bp->data;
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if(pinum)
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*pinum = de->inum;
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brelse(bp);
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return 0;
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}
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@ -499,9 +501,9 @@ dirlookup(struct inode *dp, char *name, int namelen, uint *poff, uint *pinum)
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// Write a new directory entry (name, ino) into the directory dp.
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// Caller must have locked dp.
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void
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dirwrite(struct inode *dp, char *name, uint ino)
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dirwrite(struct inode *dp, char *name, int namelen, uint ino)
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{
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int i, off;
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int off;
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struct dirent de;
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// Look for an empty dirent.
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@ -513,15 +515,37 @@ dirwrite(struct inode *dp, char *name, uint ino)
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}
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de.inum = ino;
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for(i = 0; i < DIRSIZ && name[i]; i++)
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de.name[i] = name[i];
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for(; i < DIRSIZ; i++)
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de.name[i] = '\0';
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if(namelen > DIRSIZ)
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namelen = DIRSIZ;
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memmove(de.name, name, namelen);
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memset(de.name+namelen, 0, DIRSIZ-namelen);
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if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de))
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panic("dirwrite");
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}
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// Create a new inode named name inside dp
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// and return its locked inode structure.
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// If name already exists, return 0.
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struct inode*
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dircreat(struct inode *dp, char *name, int namelen, short type, short major, short minor)
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{
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struct inode *ip;
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ip = ialloc(dp->dev, type);
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if(ip == 0)
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return 0;
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ip->major = major;
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ip->minor = minor;
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ip->size = 0;
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ip->nlink = 1;
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iupdate(ip);
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dirwrite(dp, name, namelen, ip->inum);
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return ip;
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}
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// Paths
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// Skip over the next path element in path,
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@ -564,21 +588,13 @@ skipelem(char *path, char **name, int *len)
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// NAMEI_DELETE: return locked parent inode, offset of dirent in *ret_off.
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// return 0 if name doesn't exist.
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struct inode*
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namei(char *path, int mode, uint *ret_off,
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char **ret_last, struct inode **ret_ip)
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_namei(char *path, int parent, char **pname, int *pnamelen)
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{
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struct inode *dp;
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char *name;
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int namelen;
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uint off, dev, inum;
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if(ret_off)
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*ret_off = 0xffffffff;
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if(ret_last)
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*ret_last = 0;
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if(ret_ip)
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*ret_ip = 0;
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if(*path == '/')
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dp = igetroot();
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else {
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@ -593,83 +609,63 @@ namei(char *path, int mode, uint *ret_off,
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if(dp->type != T_DIR)
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goto fail;
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if(dirlookup(dp, name, namelen, &off, &inum) < 0){
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if(mode == NAMEI_CREATE && *path == '\0'){
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*ret_last = name;
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return dp;
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}
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goto fail;
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}
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if(mode == NAMEI_DELETE && *path == '\0'){
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// can't unlink . and ..
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if((namelen == 1 && memcmp(name, ".", 1) == 0) ||
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(namelen == 2 && memcmp(name, "..", 2) == 0)){
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goto fail;
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}
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*ret_off = off;
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if(parent && *path == '\0'){
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// Stop one level early.
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*pname = name;
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*pnamelen = namelen;
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return dp;
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}
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if(dirlookup(dp, name, namelen, &off, &inum) < 0)
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goto fail;
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dev = dp->dev;
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iput(dp);
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dp = iget(dev, inum);
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if(dp->type == 0 || dp->nlink < 1)
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panic("namei");
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}
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if(mode == NAMEI_LOOKUP)
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return dp;
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if(mode == NAMEI_CREATE && ret_ip){
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*ret_ip = dp;
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if(parent)
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return 0;
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}
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goto fail;
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return dp;
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fail:
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iput(dp);
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return 0;
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}
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struct inode*
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namei(char *path)
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{
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return _namei(path, 0, 0, 0);
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}
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struct inode*
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nameiparent(char *path, char **name, int *namelen)
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{
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return _namei(path, 1, name, namelen);
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}
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// Create the path and return its locked inode structure.
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// If cp already exists, return 0.
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struct inode*
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mknod(char *path, short type, short major, short minor)
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{
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struct inode *ip, *dp;
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char *last;
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char *name;
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int namelen;
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if((dp = namei(path, NAMEI_CREATE, 0, &last, 0)) == 0)
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if((dp = nameiparent(path, &name, &namelen)) == 0)
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return 0;
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ip = mknod1(dp, last, type, major, minor);
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if(dirlookup(dp, name, namelen, 0, 0) >= 0){
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iput(dp);
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return 0;
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}
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ip = dircreat(dp, name, namelen, type, major, minor);
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iput(dp);
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return ip;
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}
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// Create a new inode named name inside dp
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// and return its locked inode structure.
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// If name already exists, return 0.
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struct inode*
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mknod1(struct inode *dp, char *name, short type, short major, short minor)
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{
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struct inode *ip;
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ip = ialloc(dp->dev, type);
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if(ip == 0)
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return 0;
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ip->major = major;
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ip->minor = minor;
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ip->size = 0;
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ip->nlink = 1;
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iupdate(ip); // write new inode to disk
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dirwrite(dp, name, ip->inum);
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return ip;
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}
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@ -680,12 +676,15 @@ unlink(char *path)
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struct inode *ip, *dp;
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struct dirent de;
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uint off, inum, dev;
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char *name;
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int namelen;
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dp = namei(path, NAMEI_DELETE, &off, 0, 0);
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if(dp == 0)
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if((dp = nameiparent(path, &name, &namelen)) == 0)
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return -1;
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dev = dp->dev;
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if(dirlookup(dp, name, namelen, &off, 0) < 0){
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iput(dp);
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return -1;
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}
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if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de) || de.inum == 0)
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panic("unlink no entry");
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@ -702,16 +701,13 @@ unlink(char *path)
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if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de))
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panic("unlink dir write");
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iupdate(dp);
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dev = dp->dev;
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iput(dp);
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ip = iget(dev, inum);
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if(ip->nlink < 1)
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panic("unlink nlink < 1");
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ip->nlink--;
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iupdate(ip);
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iput(ip);
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@ -720,21 +716,26 @@ unlink(char *path)
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// Create the path new as a link to the same inode as old.
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int
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link(char *name1, char *name2)
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link(char *old, char *new)
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{
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struct inode *ip, *dp;
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char *last;
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char *name;
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int namelen;
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if((ip = namei(name1, NAMEI_LOOKUP, 0, 0, 0)) == 0)
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if((ip = namei(old)) == 0)
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return -1;
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if(ip->type == T_DIR){
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iput(ip);
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return -1;
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}
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iunlock(ip);
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if((dp = namei(name2, NAMEI_CREATE, 0, &last, 0)) == 0) {
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if((dp = nameiparent(new, &name, &namelen)) == 0){
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idecref(ip);
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return -1;
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}
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if(dirlookup(dp, name, namelen, 0, 0) >= 0){
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iput(dp);
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idecref(ip);
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return -1;
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}
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@ -744,11 +745,12 @@ link(char *name1, char *name2)
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return -1;
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}
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// LOCKING ERROR HERE! TWO LOCKS HELD AT ONCE.
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ilock(ip);
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ip->nlink++;
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iupdate(ip);
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dirwrite(dp, last, ip->inum);
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dirwrite(dp, name, namelen, ip->inum);
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iput(dp);
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iput(ip);
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13
proc.c
13
proc.c
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@ -203,7 +203,6 @@ scheduler(void)
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void
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sched(void)
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{
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if(cp->state == RUNNING)
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panic("sched running");
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if(!holding(&proc_table_lock))
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@ -219,7 +218,6 @@ sched(void)
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void
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yield(void)
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{
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acquire(&proc_table_lock);
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cp->state = RUNNABLE;
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sched();
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@ -422,9 +420,10 @@ procdump(void)
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[RUNNING] "run ",
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[ZOMBIE] "zombie"
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};
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int i;
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int i, j;
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struct proc *p;
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char *state;
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uint pc[10];
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for(i = 0; i < NPROC; i++) {
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p = &proc[i];
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@ -434,7 +433,13 @@ procdump(void)
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state = states[p->state];
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else
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state = "???";
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cprintf("%d %s %s\n", p->pid, state, p->name);
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cprintf("%d %s %s", p->pid, state, p->name);
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if(p->state == SLEEPING) {
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getcallerpcs((uint*)p->jmpbuf.ebp+2, pc);
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for(j=0; j<10 && pc[j] != 0; j++)
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cprintf(" %p", pc[j]);
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}
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cprintf("\n");
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}
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}
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67
sysfile.c
67
sysfile.c
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@ -115,34 +115,41 @@ int
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sys_open(void)
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{
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struct inode *ip, *dp;
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char *path;
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char *path, *name;
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int namelen;
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int omode;
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int fd;
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int fd, dev;
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uint inum;
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struct file *f;
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char *last;
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if(argstr(0, &path) < 0 || argint(1, &omode) < 0)
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return -1;
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if(omode & O_CREATE){
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dp = namei(path, NAMEI_CREATE, 0, &last, &ip);
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if(dp){
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ip = mknod1(dp, last, T_FILE, 0, 0);
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switch(omode & O_CREATE){
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default:
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case 0: // regular open
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if((ip = namei(path)) == 0)
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return -1;
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break;
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case O_CREATE:
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if((dp = nameiparent(path, &name, &namelen)) == 0)
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return -1;
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if(dirlookup(dp, name, namelen, 0, &inum) >= 0){
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dev = dp->dev;
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iput(dp);
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if(ip == 0)
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ip = iget(dev, inum);
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}else{
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if((ip = dircreat(dp, name, namelen, T_FILE, 0, 0)) == 0){
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iput(dp);
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return -1;
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} else if(ip == 0){
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return -1;
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} else if(ip->type == T_DIR){
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iput(ip);
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return -1;
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}
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iput(dp);
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}
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} else {
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ip = namei(path, NAMEI_LOOKUP, 0, 0, 0);
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if(ip == 0)
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return -1;
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break;
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}
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if(ip->type == T_DIR && ((omode & O_RDWR) || (omode & O_WRONLY))){
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if(ip->type == T_DIR && (omode & (O_RDWR|O_WRONLY|O_CREATE))){
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iput(ip);
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return -1;
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}
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@ -201,18 +208,22 @@ sys_mkdir(void)
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{
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struct inode *nip;
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struct inode *dp;
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char *path;
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char *name, *path;
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struct dirent de;
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char *last;
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int namelen;
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if(argstr(0, &path) < 0)
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return -1;
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dp = namei(path, NAMEI_CREATE, 0, &last, 0);
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dp = nameiparent(path, &name, &namelen);
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if(dp == 0)
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return -1;
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if(dirlookup(dp, name, namelen, 0, 0) >= 0){
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iput(dp);
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return -1;
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}
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nip = mknod1(dp, last, T_DIR, 0, 0);
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nip = dircreat(dp, name, namelen, T_DIR, 0, 0);
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if(nip == 0){
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iput(dp);
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return -1;
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@ -245,22 +256,17 @@ sys_chdir(void)
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if(argstr(0, &path) < 0)
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return -1;
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if((ip = namei(path, NAMEI_LOOKUP, 0, 0, 0)) == 0)
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if((ip = namei(path)) == 0)
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return -1;
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if(ip == cp->cwd) {
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iput(ip);
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return 0;
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}
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if(ip->type != T_DIR) {
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iput(ip);
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return -1;
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}
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iunlock(ip);
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idecref(cp->cwd);
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cp->cwd = ip;
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iunlock(cp->cwd);
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return 0;
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}
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@ -324,8 +330,7 @@ sys_exec(void)
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if(argstr(0, &path) < 0 || argint(1, (int*)&argv) < 0)
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return -1;
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ip = namei(path, NAMEI_LOOKUP, 0, 0, 0);
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if(ip == 0)
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if((ip = namei(path)) == 0)
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return -1;
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if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
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