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,                   /* bmap */
  75         NULL,                   /* readpage */
  76         NULL,                   /* writepage */
  77         NULL,                   /* flushpage */
  78         NULL,                   /* truncate */
  79         NULL,                   /* permission */
  80         NULL,                   /* smap */
  81         NULL                    /* revalidate */
  82 };
  83
  84 int get_not_present_info(char *buffer, char **start, off_t offset, int length)
  85 {
  86     int len, pos, begin;
  87
  88     begin = 0;
  89     pos = len = sprintf(buffer,
  90                         "No low-level scsi modules are currently present\n");
  91     if(pos < offset) {
  92         len = 0;
  93         begin = pos;
  94     }
  95
  96     *start = buffer + (offset - begin);   /* Start of wanted data */
  97     len -= (offset - begin);
  98     if(len > length)
  99         len = length;
 100
 101     return(len);
 102 }
 103
 104 #define PROC_BLOCK_SIZE (3*1024)     /* 4K page size, but our output routines
 105                                       * use some slack for overruns
 106                                       */
 107
 108 static ssize_t proc_readscsi(struct file * file, char * buf,
 109                              size_t count, loff_t *ppos)
 110 {
 111     struct inode * inode = file->f_dentry->d_inode;
 112     ssize_t length;
 113     ssize_t bytes = count;
 114     ssize_t copied = 0;
 115     ssize_t thistime;
 116     char * page;
 117     char * start;
 118
 119     if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 120         return(-ENOMEM);
 121
 122     while (bytes > 0) {
 123         thistime = bytes;
 124         if(bytes > PROC_BLOCK_SIZE)
 125             thistime = PROC_BLOCK_SIZE;
 126
 127         if(dispatch_scsi_info_ptr)
 128             length = dispatch_scsi_info_ptr(inode->i_ino, page, &start,
 129                                             *ppos, thistime, 0);
 130         else
 131             length = get_not_present_info(page, &start, *ppos, thistime);
 132         if(length < 0) {
 133             free_page((ulong) page);
 134             return(length);
 135         }
 136
 137         /*
 138          *  We have been given a non page aligned block of
 139          *  the data we asked for + a bit. We have been given
 140          *  the start pointer and we know the length..
 141          */
 142         if (length <= 0)
 143             break;
 144         /*
 145          *  Copy the bytes
 146          */
 147         copy_to_user(buf + copied, start, length);
 148         *ppos += length;        /* Move down the file */
 149         bytes -= length;
 150         copied += length;
 151
 152         if(length < thistime)
 153             break;  /* End of file */
 154
 155     }
 156
 157     free_page((ulong) page);
 158     return(copied);
 159 }
 160
 161
 162 static ssize_t proc_writescsi(struct file * file, const char * buf,
 163                               size_t count, loff_t *ppos)
 164 {
 165     struct inode * inode = file->f_dentry->d_inode;
 166     ssize_t ret = 0;
 167     char * page;
 168
 169     if(count > PROC_BLOCK_SIZE) {
 170         return(-EOVERFLOW);
 171     }
 172
 173     if(dispatch_scsi_info_ptr != NULL) {
 174         if (!(page = (char *) __get_free_page(GFP_KERNEL)))
 175             return(-ENOMEM);
 176         copy_from_user(page, buf, count);
 177         ret = dispatch_scsi_info_ptr(inode->i_ino, page, 0, 0, count, 1);
 178     } else
 179         return(-ENOPKG);          /* Nothing here */
 180
 181     free_page((ulong) page);
 182     return(ret);
 183 }
 184
 185
 186 static long long proc_scsilseek(struct file * file, long long offset, int orig)
 187 {
 188     switch (orig) {
 189     case 0:
 190         file->f_pos = offset;
 191         return(file->f_pos);
 192     case 1:
 193         file->f_pos += offset;
 194         return(file->f_pos);
 195     case 2:
 196         return(-EINVAL);
 197     default:
 198         return(-EINVAL);
 199     }
 200 }
 201
 202 /*
 203  * Overrides for Emacs so that we almost follow Linus's tabbing style.
 204  * Emacs will notice this stuff at the end of the file and automatically
 205  * adjust the settings for this buffer only.  This must remain at the end
 206  * of the file.
 207  * ---------------------------------------------------------------------------
 208  * Local variables:
 209  * c-indent-level: 4
 210  * c-brace-imaginary-offset: 0
 211  * c-brace-offset: -4
 212  * c-argdecl-indent: 4
 213  * c-label-offset: -4
 214  * c-continued-statement-offset: 4
 215  * c-continued-brace-offset: 0
 216  * indent-tabs-mode: nil
 217  * tab-width: 8
 218  * End:
 219  */