i386/MIT/src.xv6/symlink.patch

   1 diff -r f8a4e40ab1d6 fs.c
   2 --- a/fs.c      Thu Aug 30 14:32:06 2007 -0400
   3 +++ b/fs.c      Thu Aug 30 14:29:02 2007 -0400
   4 @@ -577,12 +577,18 @@ skipelem(char *path, char *name)
   5  // If parent != 0, return the inode for the parent and copy the final
   6  // path element into name, which must have room for DIRSIZ bytes.
   7  static struct inode*
   8 -_namei(char *path, int parent, char *name)
   9 +_namei(struct inode *root, char *path, int parent, char *name, int depth)
  10  {
  11    struct inode *ip, *next;
  12 +  char buf[100], tname[DIRSIZ];
  13 +
  14 +  if(depth > 5)
  15 +    return 0;
  16
  17    if(*path == '/')
  18      ip = iget(ROOTDEV, 1);
  19 +  else if(root)
  20 +    ip = idup(root);
  21    else
  22      ip = idup(cp->cwd);
  23
  24 @@ -598,10 +604,24 @@ _namei(char *path, int parent, char *nam
  25        return ip;
  26      }
  27      if((next = dirlookup(ip, name, 0)) == 0){
  28 +      cprintf("did not find %s\n", name);
  29        iunlockput(ip);
  30        return 0;
  31      }
  32 -    iunlockput(ip);
  33 +    iunlock(ip);
  34 +    ilock(next);
  35 +    if(next->type == T_SYMLINK){
  36 +      if(next->size >= sizeof(buf) || readi(next, buf, 0, next->size) != next->size){
  37 +        iunlockput(next);
  38 +        iput(ip);
  39 +        return 0;
  40 +      }
  41 +      buf[next->size] = 0;
  42 +      iunlockput(next);
  43 +      next = _namei(ip, buf, 0, tname, depth+1);
  44 +    }else
  45 +      iunlock(next);
  46 +    iput(ip);
  47      ip = next;
  48    }
  49    if(parent){
  50 @@ -615,11 +635,11 @@ namei(char *path)
  51  namei(char *path)
  52  {
  53    char name[DIRSIZ];
  54 -  return _namei(path, 0, name);
  55 +  return _namei(0, path, 0, name, 0);
  56  }
  57
  58  struct inode*
  59  nameiparent(char *path, char *name)
  60  {
  61 -  return _namei(path, 1, name);
  62 -}
  63 +  return _namei(0, path, 1, name, 0);
  64 +}
  65 diff -r f8a4e40ab1d6 fs.h
  66 --- a/fs.h      Thu Aug 30 14:32:06 2007 -0400
  67 +++ b/fs.h      Thu Aug 30 13:05:43 2007 -0400
  68 @@ -33,6 +33,7 @@ struct dinode {
  69  #define T_DIR  1   // Directory
  70  #define T_FILE 2   // File
  71  #define T_DEV  3   // Special device
  72 +#define T_SYMLINK 4  // Symlink
  73
  74  // Inodes per block.
  75  #define IPB           (BSIZE / sizeof(struct dinode))
  76 diff -r f8a4e40ab1d6 syscall.c
  77 --- a/syscall.c Thu Aug 30 14:32:06 2007 -0400
  78 +++ b/syscall.c Thu Aug 30 13:05:29 2007 -0400
  79 @@ -96,6 +96,7 @@ extern int sys_unlink(void);
  80  extern int sys_unlink(void);
  81  extern int sys_wait(void);
  82  extern int sys_write(void);
  83 +extern int sys_symlink(void);
  84
  85  static int (*syscalls[])(void) = {
  86  [SYS_chdir]   sys_chdir,
  87 @@ -118,6 +119,7 @@ static int (*syscalls[])(void) = {
  88  [SYS_unlink]  sys_unlink,
  89  [SYS_wait]    sys_wait,
  90  [SYS_write]   sys_write,
  91 +[SYS_symlink]  sys_symlink,
  92  };
  93
  94  void
  95 diff -r f8a4e40ab1d6 syscall.h
  96 --- a/syscall.h Thu Aug 30 14:32:06 2007 -0400
  97 +++ b/syscall.h Thu Aug 30 13:02:48 2007 -0400
  98 @@ -19,3 +19,4 @@
  99  #define SYS_getpid 18
 100  #define SYS_sbrk   19
 101  #define SYS_sleep  20
 102 +#define SYS_symlink 21
 103 diff -r f8a4e40ab1d6 sysfile.c
 104 --- a/sysfile.c Thu Aug 30 14:32:06 2007 -0400
 105 +++ b/sysfile.c Thu Aug 30 13:10:31 2007 -0400
 106 @@ -257,6 +257,21 @@ create(char *path, int canexist, short t
 107  }
 108
 109  int
 110 +sys_symlink(void)
 111 +{
 112 +  char *old, *new;
 113 +  struct inode *ip;
 114 +
 115 +  if(argstr(0, &old) < 0 || argstr(1, &new) < 0)
 116 +    return -1;
 117 +  if((ip = create(new, 0, T_SYMLINK, 0, 0)) == 0)
 118 +    return -1;
 119 +  writei(ip, old, 0, strlen(old));
 120 +  iunlockput(ip);
 121 +  return 0;
 122 +}
 123 +
 124 +int
 125  sys_open(void)
 126  {
 127    char *path;
 128 @@ -393,3 +408,4 @@ sys_pipe(void)
 129    fd[1] = fd1;
 130    return 0;
 131  }
 132 +
 133 diff -r f8a4e40ab1d6 user.h
 134 --- a/user.h    Thu Aug 30 14:32:06 2007 -0400
 135 +++ b/user.h    Thu Aug 30 13:02:34 2007 -0400
 136 @@ -21,6 +21,7 @@ int getpid();
 137  int getpid();
 138  char* sbrk(int);
 139  int sleep(int);
 140 +int symlink(int);
 141
 142  // ulib.c
 143  int stat(char*, struct stat*);
 144 diff -r f8a4e40ab1d6 usys.S
 145 --- a/usys.S    Thu Aug 30 14:32:06 2007 -0400
 146 +++ b/usys.S    Thu Aug 30 13:05:54 2007 -0400
 147 @@ -28,3 +28,4 @@ STUB(getpid)
 148  STUB(getpid)
 149  STUB(sbrk)
 150  STUB(sleep)
 151 +STUB(symlink)