root/kernel/syscalls/link.c

/* */

DEFINITIONS

1. sys_link

   1 /*
   2  * fiwix/kernel/syscalls/link.c
   3  *
   4  * Copyright 2018, Jordi Sanfeliu. All rights reserved.
   5  * Distributed under the terms of the Fiwix License.
   6  */
   7 
   8 #include <fiwix/fs.h>
   9 #include <fiwix/stat.h>
  10 #include <fiwix/errno.h>
  11 #include <fiwix/string.h>
  12 
  13 #ifdef __DEBUG__
  14 #include <fiwix/stdio.h>
  15 #include <fiwix/process.h>
  16 #endif /*__DEBUG__ */
  17 
  18 int sys_link(const char *oldname, const char *newname)
  19 {
  20         struct inode *i, *dir, *i_new, *dir_new;
  21         char *tmp_oldname, *tmp_newname, *basename;
  22         int errno;
  23 
  24 #ifdef __DEBUG__
  25         printk("(pid %d) sys_link('%s', '%s')\n", current->pid, oldname, newname);
  26 #endif /*__DEBUG__ */
  27 
  28         if((errno = malloc_name(oldname, &tmp_oldname)) < 0) {
  29                 return errno;
  30         }
  31         if((errno = malloc_name(newname, &tmp_newname)) < 0) {
  32                 free_name(tmp_oldname);
  33                 return errno;
  34         }
  35 
  36         if((errno = namei(tmp_oldname, &i, &dir, !FOLLOW_LINKS))) {
  37                 if(dir) {
  38                         iput(dir);
  39                 }
  40                 free_name(tmp_oldname);
  41                 free_name(tmp_newname);
  42                 return errno;
  43         }
  44         if(S_ISDIR(i->i_mode)) {
  45                 iput(i);
  46                 iput(dir);
  47                 free_name(tmp_oldname);
  48                 free_name(tmp_newname);
  49                 return -EPERM;
  50         }
  51         if(IS_RDONLY_FS(i)) {
  52                 iput(i);
  53                 iput(dir);
  54                 free_name(tmp_oldname);
  55                 free_name(tmp_newname);
  56                 return -EROFS;
  57         }
  58         if(i->i_nlink == LINK_MAX) {
  59                 iput(i);
  60                 iput(dir);
  61                 free_name(tmp_oldname);
  62                 free_name(tmp_newname);
  63                 return -EMLINK;
  64         }
  65 
  66         basename = get_basename(tmp_newname);
  67         if((errno = namei(tmp_newname, &i_new, &dir_new, !FOLLOW_LINKS))) {
  68                 if(!dir_new) {
  69                         iput(i);
  70                         iput(dir);
  71                         free_name(tmp_oldname);
  72                         free_name(tmp_newname);
  73                         return errno;
  74                 }
  75         }
  76         if(!errno) {
  77                 iput(i);
  78                 iput(dir);
  79                 iput(i_new);
  80                 iput(dir_new);
  81                 free_name(tmp_oldname);
  82                 free_name(tmp_newname);
  83                 return -EEXIST;
  84         }
  85         if(i->dev != dir_new->dev) {
  86                 iput(i);
  87                 iput(dir);
  88                 iput(dir_new);
  89                 free_name(tmp_oldname);
  90                 free_name(tmp_newname);
  91                 return -EXDEV;
  92         }
  93         if(check_permission(TO_EXEC | TO_WRITE, dir_new) < 0) {
  94                 iput(i);
  95                 iput(dir);
  96                 iput(dir_new);
  97                 free_name(tmp_oldname);
  98                 free_name(tmp_newname);
  99                 return -EACCES;
 100         }
 101 
 102         if(dir_new->fsop && dir_new->fsop->link) {
 103                 errno = dir_new->fsop->link(i, dir_new, basename);
 104         } else {
 105                 errno = -EPERM;
 106         }
 107         iput(i);
 108         iput(dir);
 109         iput(dir_new);
 110         free_name(tmp_oldname);
 111         free_name(tmp_newname);
 112         return errno;
 113 }

/* */