fs/proc/base.c

/* */
This source file includes following definitions.
proc_match
proc_lookupbase
proc_readbase
   1 /*
   2  *  linux/fs/proc/base.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  proc base directory handling functions
   7  */
   8 
   9 #include <asm/segment.h>
  10 
  11 #include <linux/errno.h>
  12 #include <linux/sched.h>
  13 #include <linux/proc_fs.h>
  14 #include <linux/stat.h>
  15 
  16 static int proc_readbase(struct inode *, struct file *, struct dirent *, int);
  17 static int proc_lookupbase(struct inode *,const char *,int,struct inode **);
  18 
  19 static struct file_operations proc_base_operations = {
  20         NULL,                   /* lseek - default */
  21         NULL,                   /* read - bad */
  22         NULL,                   /* write - bad */
  23         proc_readbase,          /* readdir */
  24         NULL,                   /* select - default */
  25         NULL,                   /* ioctl - default */
  26         NULL,                   /* mmap */
  27         NULL,                   /* no special open code */
  28         NULL                    /* no special release code */
  29 };
  30 
  31 /*
  32  * proc directories can do almost nothing..
  33  */
  34 struct inode_operations proc_base_inode_operations = {
  35         &proc_base_operations,  /* default base directory file-ops */
  36         NULL,                   /* create */
  37         proc_lookupbase,        /* lookup */
  38         NULL,                   /* link */
  39         NULL,                   /* unlink */
  40         NULL,                   /* symlink */
  41         NULL,                   /* mkdir */
  42         NULL,                   /* rmdir */
  43         NULL,                   /* mknod */
  44         NULL,                   /* rename */
  45         NULL,                   /* readlink */
  46         NULL,                   /* follow_link */
  47         NULL,                   /* bmap */
  48         NULL,                   /* truncate */
  49         NULL                    /* permission */
  50 };
  51 
  52 static struct proc_dir_entry base_dir[] = {
  53         { 1,2,".." },
  54         { 2,1,"." },
  55         { 3,3,"mem" },
  56         { 4,3,"cwd" },
  57         { 5,4,"root" },
  58         { 6,3,"exe" },
  59         { 7,2,"fd" },
  60         { 8,3,"lib" },
  61         { 9,7,"environ" },
  62         { 10,7,"cmdline" },
  63         { 11,4,"stat" },
  64         { 12,5,"statm" }
  65 };
  66 
  67 #define NR_BASE_DIRENTRY ((sizeof (base_dir))/(sizeof (base_dir[0])))
  68 
  69 int proc_match(int len,const char * name,struct proc_dir_entry * de)
     /*  */
  70 {
  71         register int same __asm__("ax");
  72 
  73         if (!de || !de->low_ino)
  74                 return 0;
  75         /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
  76         if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
  77                 return 1;
  78         if (de->namelen != len)
  79                 return 0;
  80         __asm__("cld\n\t"
  81                 "fs ; repe ; cmpsb\n\t"
  82                 "setz %%al"
  83                 :"=a" (same)
  84                 :"0" (0),"S" ((long) name),"D" ((long) de->name),"c" (len)
  85                 :"cx","di","si");
  86         return same;
  87 }
  88 
  89 static int proc_lookupbase(struct inode * dir,const char * name, int len,
     /*  */
  90         struct inode ** result)
  91 {
  92         unsigned int pid;
  93         int i, ino;
  94 
  95         *result = NULL;
  96         if (!dir)
  97                 return -ENOENT;
  98         if (!S_ISDIR(dir->i_mode)) {
  99                 iput(dir);
 100                 return -ENOENT;
 101         }
 102         ino = dir->i_ino;
 103         pid = ino >> 16;
 104         i = NR_BASE_DIRENTRY;
 105         while (i-- > 0 && !proc_match(len,name,base_dir+i))
 106                 /* nothing */;
 107         if (i < 0) {
 108                 iput(dir);
 109                 return -ENOENT;
 110         }
 111         if (base_dir[i].low_ino == 1)
 112                 ino = 1;
 113         else
 114                 ino = (pid << 16) + base_dir[i].low_ino;
 115         for (i = 0 ; i < NR_TASKS ; i++)
 116                 if (task[i] && task[i]->pid == pid)
 117                         break;
 118         if (!pid || i >= NR_TASKS) {
 119                 iput(dir);
 120                 return -ENOENT;
 121         }
 122         if (!(*result = iget(dir->i_sb,ino))) {
 123                 iput(dir);
 124                 return -ENOENT;
 125         }
 126         iput(dir);
 127         return 0;
 128 }
 129 
 130 static int proc_readbase(struct inode * inode, struct file * filp,
     /*  */
 131         struct dirent * dirent, int count)
 132 {
 133         struct proc_dir_entry * de;
 134         unsigned int pid, ino;
 135         int i,j;
 136 
 137         if (!inode || !S_ISDIR(inode->i_mode))
 138                 return -EBADF;
 139         ino = inode->i_ino;
 140         pid = ino >> 16;
 141         for (i = 0 ; i < NR_TASKS ; i++)
 142                 if (task[i] && task[i]->pid == pid)
 143                         break;
 144         if (!pid || i >= NR_TASKS)
 145                 return 0;
 146         if (((unsigned) filp->f_pos) < NR_BASE_DIRENTRY) {
 147                 de = base_dir + filp->f_pos;
 148                 filp->f_pos++;
 149                 i = de->namelen;
 150                 ino = de->low_ino;
 151                 if (ino != 1)
 152                         ino |= (pid << 16);
 153                 put_fs_long(ino, &dirent->d_ino);
 154                 put_fs_word(i,&dirent->d_reclen);
 155                 put_fs_byte(0,i+dirent->d_name);
 156                 j = i;
 157                 while (i--)
 158                         put_fs_byte(de->name[i], i+dirent->d_name);
 159                 return j;
 160         }
 161         return 0;
 162 }
/* */
root/fs/proc/base.c

DEFINITIONS
