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 };
  50 
  51 static struct proc_dir_entry base_dir[] = {
  52         { 1,2,".." },
  53         { 2,1,"." },
  54         { 3,3,"mem" },
  55         { 4,3,"cwd" },
  56         { 5,4,"root" },
  57         { 6,3,"exe" },
  58         { 7,2,"fd" },
  59         { 8,3,"lib" },
  60         { 9,7,"environ" },
  61         { 10,7,"cmdline" },
  62         { 11,4,"stat" }
  63 };
  64 
  65 #define NR_BASE_DIRENTRY ((sizeof (base_dir))/(sizeof (base_dir[0])))
  66 
  67 int proc_match(int len,const char * name,struct proc_dir_entry * de)
     /*  */
  68 {
  69         register int same __asm__("ax");
  70 
  71         if (!de || !de->low_ino)
  72                 return 0;
  73         /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
  74         if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
  75                 return 1;
  76         if (de->namelen != len)
  77                 return 0;
  78         __asm__("cld\n\t"
  79                 "fs ; repe ; cmpsb\n\t"
  80                 "setz %%al"
  81                 :"=a" (same)
  82                 :"0" (0),"S" ((long) name),"D" ((long) de->name),"c" (len)
  83                 :"cx","di","si");
  84         return same;
  85 }
  86 
  87 static int proc_lookupbase(struct inode * dir,const char * name, int len,
     /*  */
  88         struct inode ** result)
  89 {
  90         unsigned int pid;
  91         int i, ino;
  92 
  93         *result = NULL;
  94         if (!dir)
  95                 return -ENOENT;
  96         if (!S_ISDIR(dir->i_mode)) {
  97                 iput(dir);
  98                 return -ENOENT;
  99         }
 100         ino = dir->i_ino;
 101         pid = ino >> 16;
 102         i = NR_BASE_DIRENTRY;
 103         while (i-- > 0 && !proc_match(len,name,base_dir+i))
 104                 /* nothing */;
 105         if (i < 0) {
 106                 iput(dir);
 107                 return -ENOENT;
 108         }
 109         if (base_dir[i].low_ino == 1)
 110                 ino = 1;
 111         else
 112                 ino = (pid << 16) + base_dir[i].low_ino;
 113         for (i = 0 ; i < NR_TASKS ; i++)
 114                 if (task[i] && task[i]->pid == pid)
 115                         break;
 116         if (!pid || i >= NR_TASKS) {
 117                 iput(dir);
 118                 return -ENOENT;
 119         }
 120         if (!(*result = iget(dir->i_sb,ino))) {
 121                 iput(dir);
 122                 return -ENOENT;
 123         }
 124         iput(dir);
 125         return 0;
 126 }
 127 
 128 static int proc_readbase(struct inode * inode, struct file * filp,
     /*  */
 129         struct dirent * dirent, int count)
 130 {
 131         struct proc_dir_entry * de;
 132         unsigned int pid, ino;
 133         int i,j;
 134 
 135         if (!inode || !S_ISDIR(inode->i_mode))
 136                 return -EBADF;
 137         ino = inode->i_ino;
 138         pid = ino >> 16;
 139         for (i = 0 ; i < NR_TASKS ; i++)
 140                 if (task[i] && task[i]->pid == pid)
 141                         break;
 142         if (!pid || i >= NR_TASKS)
 143                 return 0;
 144         if (((unsigned) filp->f_pos) < NR_BASE_DIRENTRY) {
 145                 de = base_dir + filp->f_pos;
 146                 filp->f_pos++;
 147                 i = de->namelen;
 148                 ino = de->low_ino;
 149                 if (ino != 1)
 150                         ino |= (pid << 16);
 151                 put_fs_long(ino, &dirent->d_ino);
 152                 put_fs_word(i,&dirent->d_reclen);
 153                 put_fs_byte(0,i+dirent->d_name);
 154                 j = i;
 155                 while (i--)
 156                         put_fs_byte(de->name[i], i+dirent->d_name);
 157                 return j;
 158         }
 159         return 0;
 160 }
/* */
root/fs/proc/base.c

DEFINITIONS
