root/fs/proc/scsi.c

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DEFINITIONS

This source file includes following definitions.
  1. get_not_present_info
  2. proc_readscsi
  3. proc_writescsi
  4. proc_scsilseek

   1 /*
   2  *  linux/fs/proc/scsi.c  
   3  *  (c) 1995 Michael Neuffer neuffer@goofy.zdv.uni-mainz.de
   4  *
   5  *  The original version was derived from linux/fs/proc/net.c,
   6  *  which is Copyright (C) 1991, 1992 Linus Torvalds. 
   7  *  Much has been rewritten, but some of the code still remains.
   8  *
   9  *  /proc/scsi directory handling functions
  10  *
  11  *  last change: 95/07/04    
  12  *
  13  *  Initial version: March '95
  14  *  95/05/15 Added subdirectories for each driver and show every
  15  *           registered HBA as a single file. 
  16  *  95/05/30 Added rudimentary write support for parameter passing
  17  *  95/07/04 Fixed bugs in directory handling
  18  *  95/09/13 Update to support the new proc-dir tree
  19  *
  20  *  TODO: Improve support to write to the driver files
  21  *        Add some more comments
  22  */
  23 #include <linux/autoconf.h>
  24 #include <asm/segment.h>
  25 #include <linux/errno.h>
  26 #include <linux/sched.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/stat.h>
  29 #include <linux/mm.h>
  30 
  31 /* forward references */
  32 static int proc_readscsi(struct inode * inode, struct file * file,
  33                          char * buf, int count);
  34 static int proc_writescsi(struct inode * inode, struct file * file,
  35                          const char * buf, int count);
  36 static int proc_scsilseek(struct inode *, struct file *, off_t, int);
  37 
  38 extern void build_proc_dir_hba_entries(uint);
  39 
  40 /* the *_get_info() functions are in the respective scsi driver code */
  41 extern int (* dispatch_scsi_info_ptr)(int, char *, char **, off_t, int, int);
  42     
  43     
  44 static struct file_operations proc_scsi_operations = {
  45     proc_scsilseek,     /* lseek   */
  46     proc_readscsi,      /* read    */
  47     proc_writescsi,     /* write   */
  48     proc_readdir,       /* readdir */
  49     NULL,               /* select  */
  50     NULL,               /* ioctl   */
  51     NULL,               /* mmap    */
  52     NULL,               /* no special open code    */
  53     NULL,               /* no special release code */
  54     NULL                /* can't fsync */
  55 };
  56 
  57 /*
  58  * proc directories can do almost nothing..
  59  */
  60 struct inode_operations proc_scsi_inode_operations = {
  61     &proc_scsi_operations,  /* default scsi directory file-ops */
  62     NULL,           /* create      */
  63     proc_lookup,    /* lookup      */
  64     NULL,           /* link        */
  65     NULL,           /* unlink      */
  66     NULL,           /* symlink     */
  67     NULL,           /* mkdir       */
  68     NULL,           /* rmdir       */
  69     NULL,           /* mknod       */
  70     NULL,           /* rename      */
  71     NULL,           /* readlink    */
  72     NULL,           /* follow_link */
  73     NULL,           /* bmap        */
  74     NULL,           /* truncate    */
  75     NULL            /* permission  */
  76 };
  77 
  78 int get_not_present_info(char *buffer, char **start, off_t offset, int length)
     /* [previous][next][first][last][top][bottom][index][help] */
  79 {
  80     int len, pos, begin;
  81     
  82     begin = 0;
  83     pos = len = sprintf(buffer, 
  84                         "No low-level scsi modules are currently present\n");
  85     if(pos < offset) {
  86         len = 0;
  87         begin = pos;
  88     }
  89     
  90     *start = buffer + (offset - begin);   /* Start of wanted data */
  91     len -= (offset - begin);
  92     if(len > length)
  93         len = length;
  94     
  95     return(len);
  96 }
  97 
  98 #define PROC_BLOCK_SIZE (3*1024)     /* 4K page size, but our output routines 
  99                                       * use some slack for overruns 
 100                                       */
 101 
 102 static int proc_readscsi(struct inode * inode, struct file * file,
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 103                          char * buf, int count)
 104 {
 105     int length;
 106     int bytes = count;
 107     int copied = 0;
 108     int thistime;
 109     char * page;
 110     char * start;
 111     
 112     if (count < -1)               /* Normally I wouldn't do this, */ 
 113         return(-EINVAL);          /* but it saves some redundant code.
 114                                    * Now it is possible to seek to the 
 115                                    * end of the file */
 116     if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 117         return(-ENOMEM);
 118     
 119     while(bytes > 0 || count == -1) {   
 120         thistime = bytes;
 121         if(bytes > PROC_BLOCK_SIZE || count == -1)
 122             thistime = PROC_BLOCK_SIZE;
 123         
 124         if(dispatch_scsi_info_ptr)
 125             length = dispatch_scsi_info_ptr(inode->i_ino, page, &start, 
 126                                             file->f_pos, thistime, 0);
 127         else
 128             length = get_not_present_info(page, &start, file->f_pos, thistime);
 129         if(length < 0) {
 130             free_page((ulong) page);
 131             return(length);
 132         }
 133         
 134         /*
 135          *  We have been given a non page aligned block of
 136          *  the data we asked for + a bit. We have been given
 137          *  the start pointer and we know the length.. 
 138          */
 139         if (length <= 0)
 140             break;
 141         /*
 142          *  Copy the bytes, if we're not doing a seek to 
 143          *      the end of the file 
 144          */
 145         if (count != -1)
 146             memcpy_tofs(buf + copied, start, length);
 147         file->f_pos += length;  /* Move down the file */
 148         bytes -= length;
 149         copied += length;
 150         
 151         if(length < thistime)
 152             break;  /* End of file */
 153         
 154     }
 155     
 156     free_page((ulong) page);
 157     return(copied);
 158 }
 159 
 160 
 161 static int proc_writescsi(struct inode * inode, struct file * file,
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 162                          const char * buf, int count)
 163 {
 164     int ret = 0;
 165     char * page;
 166     
 167     if(count > PROC_BLOCK_SIZE) {
 168         return(-EOVERFLOW);
 169     }
 170 
 171     if(dispatch_scsi_info_ptr != NULL) {
 172         if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 173             return(-ENOMEM);
 174         memcpy_fromfs(page, buf, count);
 175         ret = dispatch_scsi_info_ptr(inode->i_ino, page, 0, 0, count, 1);
 176     } else 
 177         return(-ENOPKG);          /* Nothing here */
 178     
 179     free_page((ulong) page);
 180     return(ret);
 181 }
 182 
 183 
 184 static int proc_scsilseek(struct inode * inode, struct file * file, 
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 185                           off_t offset, int orig)
 186 {
 187     switch (orig) {
 188     case 0:
 189         file->f_pos = offset;
 190         return(file->f_pos);
 191     case 1:
 192         file->f_pos += offset;
 193         return(file->f_pos);
 194     case 2:                  /* This ugly hack allows us to    */
 195         if (offset)          /* to determine the length of the */
 196             return(-EINVAL); /* file and then later savely to  */ 
 197         proc_readscsi(inode, file, 0, -1); /* seek in it       */ 
 198         return(file->f_pos);
 199     default:
 200         return(-EINVAL);
 201     }
 202 }
 203 
 204 /*
 205  * Overrides for Emacs so that we almost follow Linus's tabbing style.
 206  * Emacs will notice this stuff at the end of the file and automatically
 207  * adjust the settings for this buffer only.  This must remain at the end
 208  * of the file.
 209  * ---------------------------------------------------------------------------
 210  * Local variables:
 211  * c-indent-level: 4
 212  * c-brace-imaginary-offset: 0
 213  * c-brace-offset: -4
 214  * c-argdecl-indent: 4
 215  * c-label-offset: -4
 216  * c-continued-statement-offset: 4
 217  * c-continued-brace-offset: 0
 218  * indent-tabs-mode: nil
 219  * tab-width: 8
 220  * End:
 221  */

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