patch-2.1.70 linux/fs/coda/psdev.c

• Lines: 445
• Date: Tue Dec 2 14:24:04 1997
• Orig file: v2.1.69/linux/fs/coda/psdev.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.69/linux/fs/coda/psdev.c linux/fs/coda/psdev.c
@@ -0,0 +1,444 @@
+/*
+ *      	An implementation of a loadable kernel mode driver providing
+ *		multiple kernel/user space bidirectional communications links.
+ *
+ * 		Author: 	Alan Cox <alan@cymru.net>
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ * 
+ *              Adapted to become the Linux 2.0 Coda pseudo device
+ *              Peter  Braam  <braam@maths.ox.ac.uk> 
+ *              Michael Callahan <mjc@emmy.smith.edu>           
+ *
+ *              Changes for Linux 2.1
+ *              Copyright (c) 1997 Carnegie-Mellon University
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/sched.h>
+#include <linux/lp.h>
+#include <linux/malloc.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/delay.h>
+#include <linux/skbuff.h>
+#include <linux/proc_fs.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <asm/io.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <asm/poll.h>
+#include <asm/uaccess.h>
+
+#include <linux/coda.h>
+#include <linux/coda_linux.h>
+#include <linux/coda_psdev.h>
+#include <linux/coda_cnode.h>
+#include <linux/coda_namecache.h>
+#include <linux/coda_sysctl.h>
+
+
+/* 
+ * Coda stuff
+ */
+extern struct file_system_type coda_fs_type;
+extern int coda_downcall(int opcode, struct outputArgs *out);
+extern int init_coda_fs(void);
+extern int cfsnc_get_info(char *buffer, char **start, off_t offset, int length, int dummy);
+extern int cfsnc_nc_info(char *buffer, char **start, off_t offset, int length, int dummy);
+
+/* statistics */
+struct coda_upcallstats coda_callstats;
+
+extern struct coda_sb_info coda_super_info[MAX_CODADEVS];
+struct vcomm psdev_vcomm[MAX_CODADEVS];
+
+/*
+ * Device operations
+ */
+
+
+static struct vcomm *coda_psdev2vcomm(struct file *file)
+{
+       	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+	struct vcomm *vcp = NULL;
+
+	if ( (minor >= 0)  && (minor < MAX_CODADEVS) )
+	        vcp = &psdev_vcomm[minor];
+	return vcp;
+}
+	
+
+static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
+{
+        struct vcomm *vcp = coda_psdev2vcomm(file);
+	unsigned int mask = POLLOUT | POLLWRNORM;
+
+	if ( !vcp ) 
+	        return -ENXIO;
+
+	poll_wait(&(vcp->vc_waitq), wait);
+	if (!EMPTY(vcp->vc_pending))
+                mask |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+
+/*
+ *	Receive a message written by Venus to the psdev
+ */
+ 
+static ssize_t coda_psdev_write(struct file *file, const char *buf, 
+				size_t count, loff_t *off)
+{
+        struct vcomm *vcp = coda_psdev2vcomm(file);
+        struct vmsg *vmp;
+        struct outputArgs *out;
+	int error = 0;
+	int size;
+        u_long uniq;
+        u_long opcode;
+        u_long opcodebuf[2];
+        
+        if (!vcp)
+                return -ENXIO;
+
+        /* Peek at the opcode, unique id */
+	if (copy_from_user(opcodebuf, buf, 2 * sizeof(u_long)))
+	        return -EFAULT;
+	opcode = opcodebuf[0];
+        uniq = opcodebuf[1];
+
+	CDEBUG(D_PSDEV, "(process,opc,uniq)=(%d,%ld,%ld)\n", 
+	       current->pid, opcode, uniq);
+
+        if (DOWNCALL(opcode)) {
+                struct outputArgs pbuf;
+
+		CDEBUG(D_PSDEV, "handling downcall\n");
+
+              /* get the rest of the data. */
+		size = sizeof(pbuf);
+		if  ( count < sizeof(pbuf) ) {
+		        printk("Coda: downcall opc %ld, uniq %ld, not enough!\n",
+			       opcode, uniq);
+			size =count;
+		} else if ( count > sizeof(pbuf) ) {
+		        printk("Coda: downcall opc %ld, uniq %ld, too much!",
+			       opcode, uniq);
+		        size = sizeof(pbuf);
+		}
+		if (copy_from_user(&pbuf, buf, size))
+		        return -EFAULT;
+
+	      /* what errors for coda_downcall should be
+	      * sent to Venus ? 
+	      */
+		error = coda_downcall(opcode, &pbuf);
+		if ( error) {
+		        printk("psdev_write: coda_downcall error: %d\n", 
+			       error);
+			return 0;
+		}
+		return count;
+        }
+
+        
+        /* Look for the message on the processing queue. */
+        for (vmp = (struct vmsg *)GETNEXT(vcp->vc_processing);
+	     !EOQ(vmp, vcp->vc_processing);
+             vmp = (struct vmsg *)GETNEXT(vmp->vm_chain)) {
+	        if (vmp->vm_unique == uniq) break;
+		CDEBUG(D_PSDEV,"Eureka: uniq %ld on queue!\n", uniq);
+	}
+        if (EOQ(vmp, vcp->vc_processing)) {
+	        printk("psdev_write: msg (%ld, %ld) not found\n", 
+		       opcode, uniq);
+		return(-ESRCH);
+        }
+
+        /* Remove the message from the processing queue */
+        REMQUE(vmp->vm_chain);
+
+        /* move data into response buffer. */
+        /* Don't need to copy opcode and uniquifier. */
+        out = (struct outputArgs *)vmp->vm_data;
+        /* get the rest of the data. */
+        if (vmp->vm_outSize < count) {
+                printk("Coda write: too much outs: %d, cnt: %d, opc: %ld, uniq: %ld.\n",
+		       vmp->vm_outSize, count, opcode, uniq);
+		wake_up_interruptible(&vmp->vm_sleep); 	
+		return -EINVAL;
+        } else if (vmp->vm_outSize > count) {
+                printk("Coda write: too much outs: %d, cnt: %d, opc: %ld, uniq: %ld.\n",
+		       vmp->vm_outSize, count, opcode, uniq);
+	}
+        if (copy_from_user(out, buf, count))
+	        return -EFAULT;
+
+	/* adjust outsize. is this usefull ?? */
+        vmp->vm_outSize = count;	
+        vmp->vm_flags |= VM_WRITE;
+
+	CDEBUG(D_PSDEV, 
+	       "Found! Count %d for (opc,uniq)=(%ld,%ld), vmsg at %x\n", 
+	        count, opcode, uniq, (int)&vmp);
+
+        wake_up_interruptible(&vmp->vm_sleep);
+        return(count);  
+}
+
+/*
+ *	Read a message from the kernel to Venus
+ */
+
+static ssize_t coda_psdev_read(struct file * file, char * buf, 
+			    size_t count, loff_t *off)
+{
+        struct vcomm *vcp = coda_psdev2vcomm(file);
+        struct vmsg *vmp;
+	int result = count ;
+
+        if (!vcp)
+              return -ENXIO;
+        
+        /* Get message at head of request queue. */
+        if (EMPTY(vcp->vc_pending)) {
+              return 0;	/* Nothing to read */
+        }
+    
+        vmp = (struct vmsg *)GETNEXT(vcp->vc_pending);
+        REMQUE(vmp->vm_chain);
+
+        /* Move the input args into userspace */
+        
+        if (vmp->vm_inSize <= count)
+              result = vmp->vm_inSize;
+
+        if (count < vmp->vm_inSize) {
+                printk ("psdev_read: warning: venus read %d bytes of %d long 
+                                           message\n",count, vmp->vm_inSize);
+        }
+
+        if ( copy_to_user(buf, vmp->vm_data, result))
+	        return -EFAULT;
+        
+        if (vmp->vm_chain.forw == 0 || vmp->vm_chain.back == 0)
+                coda_panic("coda_psdev_read: bad chain");
+
+        /* If request was a signal, free up the message and don't
+           enqueue it in the reply queue. */
+        if (vmp->vm_opcode == CFS_SIGNAL) {
+                    CDEBUG(D_PSDEV, "vcread: signal msg (%d, %d)\n", 
+                              vmp->vm_opcode, vmp->vm_unique);
+              CODA_FREE((caddr_t)vmp->vm_data, (u_int)VC_IN_NO_DATA);
+              CODA_FREE((caddr_t)vmp, (u_int)sizeof(struct vmsg));
+              return count;
+        }
+    
+        vmp->vm_flags |= VM_READ;
+        INSQUE(vmp->vm_chain, vcp->vc_processing);
+
+        return result;
+}
+
+
+static int coda_psdev_open(struct inode * inode, struct file * file)
+{
+        register struct vcomm *vcp = NULL;
+
+        ENTRY;
+        
+	vcp = coda_psdev2vcomm(file);
+
+        if (!vcp)
+              return -ENODEV;
+	memset(vcp, 0, sizeof(struct vcomm));
+
+        MOD_INC_USE_COUNT;
+
+        INIT_QUEUE(vcp->vc_pending);
+        INIT_QUEUE(vcp->vc_processing);
+
+	cfsnc_init();
+	CDEBUG(D_PSDEV, "Name cache initialized.\n");
+
+	memset(&coda_callstats, 0, sizeof(struct coda_upcallstats));
+	EXIT;
+        return 0;
+}
+
+
+static int
+coda_psdev_release(struct inode * inode, struct file * file)
+{
+        struct vcomm *vcp;
+        struct vmsg *vmp;
+	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+
+        vcp = coda_psdev2vcomm(file);
+        
+        if ( !vcp || !vcomm_open(vcp) ) {
+              printk("psdev_release: not open");
+              return 0;
+        }
+    
+	
+	/* flush the name cache so that we can unmount */
+	CDEBUG(D_PSDEV, "Flushing the cache.\n");
+	cfsnc_flush();
+	cfsnc_use = 0;
+	CDEBUG(D_PSDEV, "Done.\n");
+	
+        /* prevent future operations on this vfs from succeeding by
+         * auto- unmounting any vfs mounted via this device. This
+         * frees user or sysadm from having to remember where all
+         * mount points are located.  Put this before WAKEUPs to avoid
+         * queuing new messages between the WAKEUP and the unmount
+         * (which can happen if we're unlucky) */
+
+        if (coda_super_info[minor].sbi_root) {
+                struct cnode *cnp = ITOC(coda_super_info[minor].sbi_root);
+                /* Let unmount know this is for real */
+                cnp->c_flags |= C_DYING;
+		/* XXX Could we force an unmount here? */
+        }
+	
+    
+        /* Wakeup clients so they can return. */
+        for (vmp = (struct vmsg *)GETNEXT(vcp->vc_pending);
+             !EOQ(vmp, vcp->vc_pending);
+             vmp = (struct vmsg *)GETNEXT(vmp->vm_chain)) {	    
+              /* Free signal request messages and don't wakeup cause
+                 no one is waiting. */
+              if (vmp->vm_opcode == CFS_SIGNAL) {
+                    CODA_FREE((caddr_t)vmp->vm_data, (u_int)VC_IN_NO_DATA);
+                    CODA_FREE((caddr_t)vmp, (u_int)sizeof(struct vmsg));
+                    continue;
+              }
+    
+              wake_up_interruptible(&vmp->vm_sleep);
+        }
+        
+        for (vmp = (struct vmsg *)GETNEXT(vcp->vc_processing);
+             !EOQ(vmp, vcp->vc_processing);
+             vmp = (struct vmsg *)GETNEXT(vmp->vm_chain)) {
+	        wake_up_interruptible(&vmp->vm_sleep);
+        }
+        
+        mark_vcomm_closed(vcp);
+	cfsnc_use = 0;
+        MOD_DEC_USE_COUNT;
+	return 0;
+}
+
+
+static struct file_operations coda_psdev_fops = {
+      NULL,                  /* llseek */
+      coda_psdev_read,       /* read */
+      coda_psdev_write,      /* write */
+      NULL,		     /* coda_psdev_readdir */
+      coda_psdev_poll,       /* poll */
+      NULL,                  /* ioctl */
+      NULL,		     /* coda_psdev_mmap */
+      coda_psdev_open,       /* open */
+      coda_psdev_release,    /* release */
+      NULL,                  /* fsync */
+      NULL,                  /* fasync */
+      NULL,                  /* check_media_change */
+      NULL,                  /* revalidate */
+      NULL                   /* lock */
+};
+
+int init_coda_psdev(void)
+{
+        
+	if(register_chrdev(CODA_PSDEV_MAJOR,"coda_psdev", &coda_psdev_fops)) {
+              printk(KERN_ERR "coda_psdev: unable to get major %d\n", 
+		     CODA_PSDEV_MAJOR);
+              return -EIO;
+	}
+        
+	return 0;
+}
+
+
+#ifdef CONFIG_PROC_FS
+
+struct proc_dir_entry proc_coda = {
+        0, 4, "coda",
+        S_IFDIR | S_IRUGO | S_IXUGO, 2, 0, 0,
+        0, &proc_net_inode_operations,
+
+};
+
+struct proc_dir_entry proc_coda_cache =  {
+                0 , 10, "coda-cache",
+                S_IFREG | S_IRUGO, 1, 0, 0,
+                0, &proc_net_inode_operations,
+                cfsnc_get_info
+        };
+
+struct proc_dir_entry proc_coda_ncstats =  {
+                0 , 12, "coda-ncstats",
+                S_IFREG | S_IRUGO, 1, 0, 0,
+                0, &proc_net_inode_operations,
+                cfsnc_nc_info
+        };
+
+#endif
+
+#ifdef MODULE
+int init_module(void)
+{
+  int status;
+  printk(KERN_INFO "Coda Kernel/User communications module 0.04\n");
+
+#ifdef CONFIG_PROC_FS
+  proc_register(&proc_root,&proc_coda);
+  proc_register(&proc_coda, &proc_coda_cache);
+  proc_register(&proc_coda, &proc_coda_ncstats);
+  coda_sysctl_init();
+#endif 
+
+  init_coda_psdev();
+  
+  if ((status = init_coda_fs()) != 0)
+    {
+      printk("coda: failed in init_coda_fs!\n");
+    }
+  return status;
+}
+
+
+void cleanup_module(void)
+{
+        int err;
+
+        ENTRY;
+
+        unregister_chrdev(CODA_PSDEV_MAJOR,"coda_psdev");
+        
+        if ( (err = unregister_filesystem(&coda_fs_type)) != 0 ) {
+                printk("coda: failed to unregister filesystem\n");
+        }
+#if CONFIG_PROC_FS
+        coda_sysctl_clean();
+        proc_unregister(&proc_coda, proc_coda_cache.low_ino);
+        proc_unregister(&proc_coda, proc_coda_ncstats.low_ino);
+	proc_unregister(&proc_root, proc_coda.low_ino);
+#endif 
+}
+
+#endif
+
+
+