ramfs.c

   1 /*******************************************************************************
   2 this code is protected by the GNU affero GPLv3
   3 author:Sylvain BERTRAND <sylvain.bertrand AT gmail dot com>
   4 *******************************************************************************/
   5 #include <ulinux/compiler_types.h>
   6 #include <ulinux/types.h>
   7 #include <ulinux/error.h>
   8 #include <ulinux/fs.h>
   9 #include <ulinux/file.h>
  10 #include <ulinux/dirent.h>
  11 #include <ulinux/utils/mem.h>
  12 #include <ulinux/utils/ascii/string/string.h>
  13 #include <ulinux/sysc.h>
  14
  15 #include "out.h"
  16 #include "ulinux_namespace.h"
  17 #include "globals.h"
  18
  19 #define DIRENTS_BUF_SZ 8192
  20
  21 static u8 is_current(u8 *n)
  22 {
  23   if(n[0]=='.'&&n[1]==0) return 1;
  24   return 0;
  25 }
  26
  27 static u8 is_parent(u8 *n)
  28 {
  29   if(n[0]=='.'&&n[1]=='.'&&n[2]==0) return 1;
  30   return 0;
  31 }
  32
  33 static u8 is_newroot(u8 *n)
  34 {
  35   #define NEWROOT (u8*)"newroot"
  36   return strncmp(n,NEWROOT,sizeof(NEWROOT)-1)?0:1;
  37 }
  38
  39 static void unlink(i parent_fd,u8 *n,i flgs)
  40 {
  41   l r=unlinkat(parent_fd,n,flgs);
  42   if(ISERR(r)){
  43     OUT("ERROR(%ld):unable to remove dir entry:%s\n",r,n);
  44     exit_group(-1);
  45   }
  46 }
  47
  48 static void dir_del(i parent_fd);
  49 static void dirent_del(i parent_fd,struct dirent64 *d)
  50 {
  51   if(d->type==DT_DIR){
  52     if(!is_current(d->name)&&!is_parent(d->name)){
  53       i dir_fd;
  54       loop{
  55         dir_fd=(i)openat(parent_fd,d->name,ULINUX_O_RDONLY|ULINUX_O_NONBLOCK);
  56         if(dir_fd!=-EINTR) break;
  57       }
  58       if(ISERR(dir_fd)){
  59         OUT("ERROR(%d):unable to open subdir:%s\n",dir_fd,d->name);
  60         exit_group(-1);
  61       }else{
  62         l r;
  63         dir_del(dir_fd);
  64         loop{
  65           r=close(dir_fd);
  66           if(r!=-EINTR) break;
  67         }
  68         if(ISERR(r)){
  69           OUT("ERROR(%ld):unable to close dir fd\n",r);
  70           exit_group(-1);
  71         }
  72       }
  73       unlink(parent_fd,d->name,AT_REMOVEDIR);
  74     }
  75   }else unlink(parent_fd,d->name,0);
  76 }
  77
  78 static void dir_del(i parent_fd)
  79 {
  80   u8 dirents[DIRENTS_BUF_SZ];
  81   loop{
  82     l idx;
  83     l r=getdents64(parent_fd,dirents,DIRENTS_BUF_SZ);
  84     if(ISERR(r)){
  85       OUT("ERROR(%ld):getdents error\n",r);
  86       exit_group(-1);
  87     }
  88
  89     if(!r) break;
  90
  91     idx=0;
  92     loop{
  93       struct dirent64 *d;
  94
  95       if(idx>=r) break;
  96       d=(struct dirent64*)(dirents+idx);
  97       dirent_del(parent_fd,d);
  98       idx+=d->rec_len;
  99     }
 100   }
 101 }
 102
 103 void ramfs_cleanup(void)
 104 {
 105   OUT(PRE "cleaning ramfs...");
 106   i root_fd;
 107   loop{
 108     root_fd=(i)open("/",ULINUX_O_RDONLY|ULINUX_O_NONBLOCK);
 109     if(root_fd!=-EINTR) break;
 110   }
 111   if(ISERR(root_fd)){
 112     OUT("ERROR(%d):unable to open root dir\n",root_fd);
 113     exit_group(-1);
 114   }
 115
 116   u8 dirents[DIRENTS_BUF_SZ];
 117   loop{
 118     l idx;
 119     l r=getdents64(root_fd,dirents,DIRENTS_BUF_SZ);
 120     if(ISERR(r)){
 121       OUT("ERROR(%ld):getdents error\n",r);
 122       exit_group(-1);
 123     }
 124
 125     if(!r) break;/*empty*/
 126
 127     idx=0;
 128     loop{
 129       struct dirent64 *d;
 130
 131       if(idx>=r) break;
 132
 133       d=(struct dirent64*)(dirents+idx);
 134       if(!is_newroot(d->name)) dirent_del(root_fd,d);
 135       idx+=d->rec_len;
 136     }
 137   }
 138   l r;
 139   loop{
 140     r=close(root_fd);
 141     if(r!=-EINTR) break;
 142   }
 143   if(ISERR(r)){
 144     OUT("ERROR(%ld):unable to root dir fd\n",r);
 145     exit_group(-1);
 146   }
 147   OUT("done\n");
 148 }