/* -*- C -*- * main.c -- the bare scullv char module * * $Id: _main.c.in,v 1.17 2001/03/16 20:27:26 corbet Exp $ * * Mmap is not available on the Sparc, as pgd_offset etc. are not * yet exported to modules. Nonetheless, I've been able to run this * code by tweaking the loading mechanism. */#ifndef __KERNEL__#  define __KERNEL__#endif#ifndef MODULE#  define MODULE#endif#include <linux/config.h>#include <linux/module.h>/* modversion stuff: no #ifdef needed if 2.0 support is not needed */#ifdef CONFIG_MODVERSIONS#  include <linux/modversions.h>#endif#include <linux/kernel.h> /* printk() */#include <linux/malloc.h> /* kmalloc() */#include <linux/fs.h>     /* everything... */#include <linux/errno.h>  /* error codes */#include <linux/types.h>  /* size_t */#include <linux/proc_fs.h>#include <linux/fcntl.h>        /* O_ACCMODE */#include <asm/system.h>   /* cli(), *_flags */#include "scullv.h"        /* local definitions *//* * I don't use static symbols here, because register_symtab is called */int scullv_major =   SCULLV_MAJOR;int scullv_devs =    SCULLV_DEVS;    /* number of bare scullv devices */int scullv_qset =    SCULLV_QSET;int scullv_order =   SCULLV_ORDER;MODULE_PARM(scullv_major, "i");MODULE_PARM(scullv_devs, "i");MODULE_PARM(scullv_qset, "i");MODULE_PARM(scullv_order, "i");MODULE_AUTHOR("Alessandro Rubini");ScullV_Dev *scullv_devices; /* allocated in scullv_init */int scullv_trim(ScullV_Dev *dev);#ifdef SCULLV_USE_PROC /* don't waste space if unused *//* * The proc filesystem: function to read and entry */void scullv_proc_offset(char *buf, char **start, off_t *offset, int *len){    if (*offset == 0)        return;    if (*offset >= *len) {      /* Not there yet */        *offset -= *len;        *len = 0;    }    else {                      /* We're into the interesting stuff now */        *start = buf + *offset;        *offset = 0;    }}int scullv_read_procmem(char *buf, char **start, off_t offset,                   int count, int *eof, void *data){    int i, j, order, qset, len = 0;    int limit = count - 80; /* Don't print more than this */    ScullV_Dev *d;    *start = buf;    for(i=0; i<scullv_devs; i++) {        d=&scullv_devices[i];        if (down_interruptible (&d->sem))                return -ERESTARTSYS;        qset=d->qset;  /* retrieve the features of each device */        order=d->order;        len += sprintf(buf+len,"\nDevice %i: qset %i, order %i, sz %li\n",                       i, qset, order, (long)(d->size));        for (; d; d=d->next) { /* scan the list */            len += sprintf(buf+len,"  item at %p, qset at %p\n",d,d->data);            scullv_proc_offset (buf, start, &offset, &len);            if (len > limit)                goto out;            if (d->data && !d->next) /* dump only the last item - save space */                for (j=0; j<qset; j++) {                    if (d->data[j])                        len += sprintf(buf+len,"    % 4i:%8p\n",j,d->data[j]);                    scullv_proc_offset (buf, start, &offset, &len);                    if (len > limit)                        goto out;		}        }    out:        up (&scullv_devices[i].sem);	if (len > limit)	    break;    }    *eof = 1;    return len;}#ifdef USE_PROC_REGISTERstatic int scullv_get_info (char *buf, char **start, off_t offset,                int len, int unused){    int eof = 0;    return scullv_read_procmem(buf, start, offset, len, &eof, NULL);}struct proc_dir_entry scullv_proc_entry = {        0,                 /* low_ino: the inode -- dynamic */        9, "scullvmem",     /* len of name and name */        S_IFREG | S_IRUGO, /* mode */        1, 0, 0,           /* nlinks, owner, group */        0, NULL,           /* size - unused; operations -- use default */        scullv_get_info,   /* function used to read data */        /* nothing more */    };static inline void create_proc_read_entry (const char *name, mode_t mode,                struct proc_dir_entry *base, void *read_func, void *data){    proc_register_dynamic (&proc_root, &scullv_proc_entry);}static inline void remove_proc_entry (char *name, void *parent){    proc_unregister (&proc_root, scullv_proc_entry.low_ino);}#endif /* USE_PROC_REGISTER */#endif /* SCULLV_USE_PROC *//* * Open and close */int scullv_open (struct inode *inode, struct file *filp){    int num = MINOR(inode->i_rdev);    ScullV_Dev *dev; /* device information */    /*  check the device number */    if (num >= scullv_devs) return -ENODEV;    dev = &scullv_devices[num];    /* now trim to 0 the length of the device if open was write-only */     if ( (filp->f_flags & O_ACCMODE) == O_WRONLY) {        if (down_interruptible (&dev->sem))            return -ERESTARTSYS;        scullv_trim(dev); /* ignore errors */        up (&dev->sem);    }    /* and use filp->private_data to point to the device data */    filp->private_data = dev;    MOD_INC_USE_COUNT;    return 0;          /* success */}int scullv_release (struct inode *inode, struct file *filp){    MOD_DEC_USE_COUNT;    return 0;}/* * Follow the list  */ScullV_Dev *scullv_follow(ScullV_Dev *dev, int n){    while (n--) {        if (!dev->next) {            dev->next = kmalloc(sizeof(ScullV_Dev), GFP_KERNEL);            memset(dev->next, 0, sizeof(ScullV_Dev));        }        dev = dev->next;        continue;    }    return dev;}/* * Data management: read and write */ssize_t scullv_read (struct file *filp, char *buf, size_t count,                loff_t *f_pos){    ScullV_Dev *dev = filp->private_data; /* the first listitem */    ScullV_Dev *dptr;    int quantum = PAGE_SIZE << dev->order;    int qset = dev->qset;    int itemsize = quantum * qset; /* how many bytes in the listitem */    int item, s_pos, q_pos, rest;    ssize_t retval = 0;    if (down_interruptible (&dev->sem))            return -ERESTARTSYS;    if (*f_pos > dev->size)         goto nothing;    if (*f_pos + count > dev->size)        count = dev->size - *f_pos;    /* find listitem, qset index, and offset in the quantum */    item = ((long) *f_pos) / itemsize;    rest = ((long) *f_pos) % itemsize;    s_pos = rest / quantum; q_pos = rest % quantum;    /* follow the list up to the right position (defined elsewhere) */    dptr = scullv_follow(dev, item);    if (!dptr->data)        goto nothing; /* don't fill holes */    if (!dptr->data[s_pos])        goto nothing;    if (count > quantum - q_pos)        count = quantum - q_pos; /* read only up to the end of this quantum */    if (copy_to_user (buf, dptr->data[s_pos]+q_pos, count)) {        retval = -EFAULT;        goto nothing;    }    up (&dev->sem);    *f_pos += count;    return count;  nothing:    up (&dev->sem);    return retval;}ssize_t scullv_write (struct file *filp, const char *buf, size_t count,                loff_t *f_pos){    ScullV_Dev *dev = filp->private_data;    ScullV_Dev *dptr;    int quantum = PAGE_SIZE << dev->order;    int qset = dev->qset;    int itemsize = quantum * qset;    int item, s_pos, q_pos, rest;    ssize_t retval = -ENOMEM; /* our most likely error */    if (down_interruptible (&dev->sem))            return -ERESTARTSYS;    /* find listitem, qset index and offset in the quantum */    item = ((long) *f_pos) / itemsize;    rest = ((long) *f_pos) % itemsize;    s_pos = rest / quantum; q_pos = rest % quantum;    /* follow the list up to the right position */    dptr = scullv_follow(dev, item);    if (!dptr->data) {        dptr->data = kmalloc(qset * sizeof(void *), GFP_KERNEL);        if (!dptr->data)            goto nomem;        memset(dptr->data, 0, qset * sizeof(char *));    }    /* Allocate a quantum using virtual addresses */    if (!dptr->data[s_pos]) {        dptr->data[s_pos] =	    (void *)vmalloc(PAGE_SIZE << dptr->order);        if (!dptr->data[s_pos])            goto nomem;        memset(dptr->data[s_pos], 0, PAGE_SIZE << dptr->order);    }    if (count > quantum - q_pos)        count = quantum - q_pos; /* write only up to the end of this quantum */    if (copy_from_user (dptr->data[s_pos]+q_pos, buf, count)) {        retval = -EFAULT;        goto nomem;    }    *f_pos += count;     /* update the size */    if (dev->size < *f_pos)        dev->size = *f_pos;    up (&dev->sem);    return count;  nomem:    up (&dev->sem);    return retval;}/* * The ioctl() implementation */int scullv_ioctl (struct inode *inode, struct file *filp,                 unsigned int cmd, unsigned long arg){    int err= 0, ret = 0, tmp;    /* don't even decode wrong cmds: better returning  ENOTTY than EFAULT */    if (_IOC_TYPE(cmd) != SCULLV_IOC_MAGIC) return -ENOTTY;    if (_IOC_NR(cmd) > SCULLV_IOC_MAXNR) return -ENOTTY;    /*     * the type is a bitmask, and VERIFY_WRITE catches R/W     * transfers. Note that the type is user-oriented, while     * verify_area is kernel-oriented, so the concept of "read" and     * "write" is reversed     */    if (_IOC_DIR(cmd) & _IOC_READ)        err = !access_ok(VERIFY_WRITE, (void *)arg, _IOC_SIZE(cmd));    else if (_IOC_DIR(cmd) & _IOC_WRITE)        err =  !access_ok(VERIFY_READ, (void *)arg, _IOC_SIZE(cmd));    if (err) return -EFAULT;    switch(cmd) {      case SCULLV_IOCRESET:        scullv_qset = SCULLV_QSET;        scullv_order = SCULLV_ORDER;        break;              case SCULLV_IOCSORDER: /* Set: arg points to the value */        ret = __GET_USER(scullv_order, (int *) arg);        break;      case SCULLV_IOCTORDER: /* Tell: arg is the value */        scullv_order = arg;        break;      case SCULLV_IOCGORDER: /* Get: arg is pointer to result */        ret = __PUT_USER (scullv_order, (int *) arg);        break;      case SCULLV_IOCQORDER: /* Query: return it (it's positive) */        return scullv_order;      case SCULLV_IOCXORDER: /* eXchange: use arg as pointer */        tmp = scullv_order;        ret = __GET_USER(scullv_order, (int *) arg);        if (ret == 0)            ret = __PUT_USER(tmp, (int *) arg);        break;      case SCULLV_IOCHORDER: /* sHift: like Tell + Query */        tmp = scullv_order;        scullv_order = arg;        return tmp;              case SCULLV_IOCSQSET:        ret = __GET_USER(scullv_qset, (int *) arg);        break;      case SCULLV_IOCTQSET:        scullv_qset = arg;        break;      case SCULLV_IOCGQSET:        ret = __PUT_USER(scullv_qset, (int *)arg);        break;      case SCULLV_IOCQQSET:        return scullv_qset;      case SCULLV_IOCXQSET:        tmp = scullv_qset;        ret = __GET_USER(scullv_qset, (int *) arg);        if (ret == 0)            ret = __PUT_USER(tmp, (int *)arg);        break;      case SCULLV_IOCHQSET:        tmp = scullv_qset;        scullv_qset = arg;        return tmp;      default:  /* redundant, as cmd was checked against MAXNR */        return -ENOTTY;    }    return ret;}/* * The "extended" operations */loff_t scullv_llseek (struct file *filp, loff_t off, int whence){    ScullV_Dev *dev = filp->private_data;    long newpos;    switch(whence) {      case 0: /* SEEK_SET */        newpos = off;        break;      case 1: /* SEEK_CUR */        newpos = filp->f_pos + off;        break;      case 2: /* SEEK_END */        newpos = dev->size + off;        break;      default: /* can't happen */        return -EINVAL;    }    if (newpos<0) return -EINVAL;    filp->f_pos = newpos;    return newpos;} /* * Mmap *is* available, but confined in a different file */#ifndef LINUX_20extern int scullv_mmap(struct file *filp, struct vm_area_struct *vma);#elseextern int scullv_mmap(struct inode *inode, struct file *filp,		struct vm_area_struct *vma);#endif/* * The 2.0 wrappers */#ifdef LINUX_20int scullv_lseek_20 (struct inode *ino, struct file *f,                off_t offset, int whence){    return (int)scullv_llseek(f, offset, whence);}int scullv_read_20 (struct inode *ino, struct file *f, char *buf, int count){    return (int)scullv_read(f, buf, count, &f->f_pos);}int scullv_write_20 (struct inode *ino, struct file *f, const char *b, int c){    return (int)scullv_write(f, b, c, &f->f_pos);}void scullv_release_20 (struct inode *ino, struct file *f){    scullv_release(ino, f);}#define scullv_llseek scullv_lseek_20#define scullv_read scullv_read_20#define scullv_write scullv_write_20#define scullv_release scullv_release_20#define llseek lseek#endif /* LINUX_20 *//* * The fops */struct file_operations scullv_fops = {    llseek: scullv_llseek,    read: scullv_read,    write: scullv_write,    ioctl: scullv_ioctl,    mmap: scullv_mmap,    open: scullv_open,    release: scullv_release,};int scullv_trim(ScullV_Dev *dev){    ScullV_Dev *next, *dptr;    int qset = dev->qset;   /* "dev" is not-null */    int i;    if (dev->vmas) /* don't trim: there are active mappings */        return -EBUSY;    for (dptr = dev; dptr; dptr = next) { /* all the list items */        if (dptr->data) {            /* Release the quantum-set */            for (i = 0; i < qset; i++)                if (dptr->data[i])                    vfree(dptr->data[i]);            kfree(dptr->data);            dptr->data=NULL;        }        next=dptr->next;        if (dptr != dev) kfree(dptr); /* all of them but the first */    }    dev->size = 0;    dev->qset = scullv_qset;    dev->order = scullv_order;    dev->next = NULL;    return 0;}/* * Finally, the module stuff */int scullv_init(void){    int result, i;    SET_MODULE_OWNER(&scullv_fops);    /*     * Register your major, and accept a dynamic number     */    result = register_chrdev(scullv_major, "scullv", &scullv_fops);    if (result < 0) return result;    if (scullv_major == 0) scullv_major = result; /* dynamic */    /*      * allocate the devices -- we can't have them static, as the number     * can be specified at load time     */    scullv_devices = kmalloc(scullv_devs * sizeof (ScullV_Dev), GFP_KERNEL);    if (!scullv_devices) {        result = -ENOMEM;        goto fail_malloc;    }    memset(scullv_devices, 0, scullv_devs * sizeof (ScullV_Dev));    for (i=0; i < scullv_devs; i++) {        scullv_devices[i].order = scullv_order;        scullv_devices[i].qset = scullv_qset;        sema_init (&scullv_devices[i].sem, 1);    }#ifdef SCULLV_USE_PROC /* only when available */    create_proc_read_entry("scullvmem", 0, NULL, scullv_read_procmem, NULL);#endif    return 0; /* succeed */  fail_malloc:    unregister_chrdev(scullv_major, "scullv");    return result;}void scullv_cleanup(void){    int i;    unregister_chrdev(scullv_major, "scullv");#ifdef SCULLV_USE_PROC    remove_proc_entry("scullvmem", 0);#endif    for (i=0; i<scullv_devs; i++)        scullv_trim(scullv_devices+i);    kfree(scullv_devices);}module_init(scullv_init);module_exit(scullv_cleanup);