fs/proc/fd.c

/* */
This source file includes following definitions.
proc_lookupfd
proc_readfd
   1 /*
   2  *  linux/fs/proc/fd.c
   3  *
   4  *  Copyright (C) 1991, 1992 Linus Torvalds
   5  *
   6  *  proc fd 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_readfd(struct inode *, struct file *, void *, filldir_t);
  17 static int proc_lookupfd(struct inode *,const char *,int,struct inode **);
  18 
  19 static struct file_operations proc_fd_operations = {
  20         NULL,                   /* lseek - default */
  21         NULL,                   /* read - bad */
  22         NULL,                   /* write - bad */
  23         proc_readfd,            /* 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         NULL                    /* can't fsync */
  30 };
  31 
  32 /*
  33  * proc directories can do almost nothing..
  34  */
  35 struct inode_operations proc_fd_inode_operations = {
  36         &proc_fd_operations,    /* default base directory file-ops */
  37         NULL,                   /* create */
  38         proc_lookupfd,          /* lookup */
  39         NULL,                   /* link */
  40         NULL,                   /* unlink */
  41         NULL,                   /* symlink */
  42         NULL,                   /* mkdir */
  43         NULL,                   /* rmdir */
  44         NULL,                   /* mknod */
  45         NULL,                   /* rename */
  46         NULL,                   /* readlink */
  47         NULL,                   /* follow_link */
  48         NULL,                   /* bmap */
  49         NULL,                   /* truncate */
  50         NULL                    /* permission */
  51 };
  52 
  53 static int proc_lookupfd(struct inode * dir,const char * name, int len,
     /*  */
  54         struct inode ** result)
  55 {
  56         unsigned int ino, pid, fd, c;
  57         struct task_struct * p;
  58         struct super_block * sb;
  59         int i;
  60 
  61         *result = NULL;
  62         ino = dir->i_ino;
  63         pid = ino >> 16;
  64         ino &= 0x0000ffff;
  65         if (!dir)
  66                 return -ENOENT;
  67         sb = dir->i_sb;
  68         if (!pid || ino != PROC_PID_FD || !S_ISDIR(dir->i_mode)) {
  69                 iput(dir);
  70                 return -ENOENT;
  71         }
  72         if (!len || (name[0] == '.' && (len == 1 ||
  73             (name[1] == '.' && len == 2)))) {
  74                 if (len < 2) {
  75                         *result = dir;
  76                         return 0;
  77                 }
  78                 if (!(*result = iget(sb,(pid << 16)+PROC_PID_INO))) {
  79                         iput(dir);
  80                         return -ENOENT;
  81                 }
  82                 iput(dir);
  83                 return 0;
  84         }
  85         iput(dir);
  86         fd = 0;
  87         while (len-- > 0) {
  88                 c = *name - '0';
  89                 name++;
  90                 if (c > 9) {
  91                         fd = 0xfffff;
  92                         break;
  93                 }
  94                 fd *= 10;
  95                 fd += c;
  96                 if (fd & 0xffff0000) {
  97                         fd = 0xfffff;
  98                         break;
  99                 }
 100         }
 101         for (i = 0 ; i < NR_TASKS ; i++)
 102                 if ((p = task[i]) && p->pid == pid)
 103                         break;
 104         if (!pid || i >= NR_TASKS)
 105                 return -ENOENT;
 106 
 107         if (fd >= NR_OPEN || !p->files->fd[fd] || !p->files->fd[fd]->f_inode)
 108           return -ENOENT;
 109 
 110         ino = (pid << 16) + (PROC_PID_FD_DIR << 8) + fd;
 111 
 112         if (!(*result = iget(sb,ino)))
 113                 return -ENOENT;
 114         return 0;
 115 }
 116 
 117 #define NUMBUF 10
 118 
 119 static int proc_readfd(struct inode * inode, struct file * filp,
     /*  */
 120         void * dirent, filldir_t filldir)
 121 {
 122         char buf[NUMBUF];
 123         int task_nr;
 124         struct task_struct * p;
 125         unsigned int fd, pid, ino;
 126         unsigned long i,j;
 127 
 128         if (!inode || !S_ISDIR(inode->i_mode))
 129                 return -EBADF;
 130         ino = inode->i_ino;
 131         pid = ino >> 16;
 132         ino &= 0x0000ffff;
 133         if (ino != PROC_PID_FD)
 134                 return 0;
 135 
 136         for (fd = filp->f_pos; fd < 2; fd++, filp->f_pos++) {
 137                 unsigned long ino = inode->i_ino;
 138                 if (fd)
 139                         ino = (ino & 0xffff0000) | PROC_PID_INO;
 140                 if (filldir(dirent, "..", fd+1, fd, ino) < 0)
 141                         return 0;
 142         }
 143 
 144         task_nr = 1;
 145         for (;;) {
 146                 if ((p = task[task_nr]) && p->pid == pid)
 147                         break;
 148                 if (++task_nr >= NR_TASKS)
 149                         return 0;
 150         }
 151 
 152         for (fd -= 2 ; fd < NR_OPEN; fd++, filp->f_pos++) {
 153                 if (!p->files->fd[fd] || !p->files->fd[fd]->f_inode)
 154                         continue;
 155 
 156                 j = NUMBUF;
 157                 i = fd;
 158                 do {
 159                         j--;
 160                         buf[j] = '0' + (i % 10);
 161                         i /= 10;
 162                 } while (i);
 163 
 164                 ino = (pid << 16) + (PROC_PID_FD_DIR << 8) + fd;
 165                 if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino) < 0)
 166                         break;
 167 
 168                 /* filldir() migth have slept, so we must re-validate "p" */
 169                 if (p != task[task_nr] || p->pid != pid)
 170                         break;
 171         }
 172         return 0;
 173 }
/* */
root/fs/proc/fd.c

DEFINITIONS
