fs/proc/scsi.c

   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/errno.h>
  24 #include <linux/sched.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/stat.h>
  27 #include <linux/mm.h>
  28
  29 #include <asm/uaccess.h>
  30
  31 /* forward references */
  32 static ssize_t proc_readscsi(struct file * file, char * buf,
  33                              size_t count, loff_t *ppos);
  34 static ssize_t proc_writescsi(struct file * file, const char * buf,
  35                               size_t count, loff_t *ppos);
  36 static long long proc_scsilseek(struct file *, long long, 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 int (* dispatch_scsi_info_ptr) (int ino, char *buffer, char **start,
  42                                 off_t offset, int length, int inout) = 0;
  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,               /* poll    */
  50     NULL,               /* ioctl   */
  51     NULL,               /* mmap    */
  52     NULL,               /* no special open code    */
  53     NULL,               /* flush */
  54     NULL,               /* no special release code */
  55     NULL                /* can't fsync */
  56 };
  57
  58 /*
  59  * proc directories can do almost nothing..
  60  */
  61 struct inode_operations proc_scsi_inode_operations = {
  62     &proc_scsi_operations,  /* default scsi directory file-ops */
  63     NULL,           /* create      */
  64     proc_lookup,    /* lookup      */
  65     NULL,           /* link        */
  66     NULL,           /* unlink      */
  67     NULL,           /* symlink     */
  68     NULL,           /* mkdir       */
  69     NULL,           /* rmdir       */
  70     NULL,           /* mknod       */
  71     NULL,           /* rename      */
  72     NULL,           /* readlink    */
  73     NULL,           /* follow_link */
  74     NULL,           /* readpage    */
  75     NULL,           /* writepage   */
  76     NULL,           /* bmap        */
  77     NULL,           /* truncate    */
  78     NULL            /* permission  */
  79 };
  80
  81 int get_not_present_info(char *buffer, char **start, off_t offset, int length)
  82 {
  83     int len, pos, begin;
  84
  85     begin = 0;
  86     pos = len = sprintf(buffer,
  87                         "No low-level scsi modules are currently present\n");
  88     if(pos < offset) {
  89         len = 0;
  90         begin = pos;
  91     }
  92
  93     *start = buffer + (offset - begin);   /* Start of wanted data */
  94     len -= (offset - begin);
  95     if(len > length)
  96         len = length;
  97
  98     return(len);
  99 }
 100
 101 #define PROC_BLOCK_SIZE (3*1024)     /* 4K page size, but our output routines
 102                                       * use some slack for overruns
 103                                       */
 104
 105 static ssize_t proc_readscsi(struct file * file, char * buf,
 106                              size_t count, loff_t *ppos)
 107 {
 108     struct inode * inode = file->f_dentry->d_inode;
 109     ssize_t length;
 110     ssize_t bytes = count;
 111     ssize_t copied = 0;
 112     ssize_t thistime;
 113     char * page;
 114     char * start;
 115
 116     if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 117         return(-ENOMEM);
 118
 119     while (bytes > 0) {
 120         thistime = bytes;
 121         if(bytes > PROC_BLOCK_SIZE)
 122             thistime = PROC_BLOCK_SIZE;
 123
 124         if(dispatch_scsi_info_ptr)
 125             length = dispatch_scsi_info_ptr(inode->i_ino, page, &start,
 126                                             *ppos, thistime, 0);
 127         else
 128             length = get_not_present_info(page, &start, *ppos, 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
 143          */
 144         copy_to_user(buf + copied, start, length);
 145         *ppos += length;        /* Move down the file */
 146         bytes -= length;
 147         copied += length;
 148
 149         if(length < thistime)
 150             break;  /* End of file */
 151
 152     }
 153
 154     free_page((ulong) page);
 155     return(copied);
 156 }
 157
 158
 159 static ssize_t proc_writescsi(struct file * file, const char * buf,
 160                               size_t count, loff_t *ppos)
 161 {
 162     struct inode * inode = file->f_dentry->d_inode;
 163     ssize_t ret = 0;
 164     char * page;
 165
 166     if(count > PROC_BLOCK_SIZE) {
 167         return(-EOVERFLOW);
 168     }
 169
 170     if(dispatch_scsi_info_ptr != NULL) {
 171         if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 172             return(-ENOMEM);
 173         copy_from_user(page, buf, count);
 174         ret = dispatch_scsi_info_ptr(inode->i_ino, page, 0, 0, count, 1);
 175     } else
 176         return(-ENOPKG);          /* Nothing here */
 177
 178     free_page((ulong) page);
 179     return(ret);
 180 }
 181
 182
 183 static long long proc_scsilseek(struct file * file, long long offset, int orig)
 184 {
 185     switch (orig) {
 186     case 0:
 187         file->f_pos = offset;
 188         return(file->f_pos);
 189     case 1:
 190         file->f_pos += offset;
 191         return(file->f_pos);
 192     case 2:
 193         return(-EINVAL);
 194     default:
 195         return(-EINVAL);
 196     }
 197 }
 198
 199 /*
 200  * Overrides for Emacs so that we almost follow Linus's tabbing style.
 201  * Emacs will notice this stuff at the end of the file and automatically
 202  * adjust the settings for this buffer only.  This must remain at the end
 203  * of the file.
 204  * ---------------------------------------------------------------------------
 205  * Local variables:
 206  * c-indent-level: 4
 207  * c-brace-imaginary-offset: 0
 208  * c-brace-offset: -4
 209  * c-argdecl-indent: 4
 210  * c-label-offset: -4
 211  * c-continued-statement-offset: 4
 212  * c-continued-brace-offset: 0
 213  * indent-tabs-mode: nil
 214  * tab-width: 8
 215  * End:
 216  */