patch-2.1.43 linux/fs/proc/omirr.c

• Lines: 298
• Date: Thu Jun 12 16:22:09 1997
• Orig file: v2.1.42/linux/fs/proc/omirr.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.42/linux/fs/proc/omirr.c linux/fs/proc/omirr.c
@@ -0,0 +1,297 @@
+/*
+ * fs/proc/omirr.c  -  online mirror support
+ *
+ * (C) 1997 Thomas Schoebel-Theuer
+ */
+
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/dalloc.h>
+#include <linux/omirr.h>
+#include <asm/uaccess.h>
+
+static int nr_omirr_open = 0;
+static int cleared_flag = 0;
+
+static char * buffer = NULL;
+static int read_pos, write_pos;
+static int clip_pos, max_pos;
+static struct wait_queue * read_wait = NULL;
+static struct wait_queue * write_wait = NULL;
+
+static /*inline*/ int reserve_write_space(int len)
+{
+	int rest = max_pos - write_pos;
+
+	if(rest < len) {
+		clip_pos = write_pos;
+		write_pos = 0;
+		rest = max_pos;
+	}
+	while(read_pos > write_pos && read_pos <= write_pos+len) {
+		if(!nr_omirr_open)
+			return 0;
+		interruptible_sleep_on(&write_wait);
+	}
+	return 1;
+}
+
+static /*inline*/ void write_space(int len)
+{
+	write_pos += len;
+	wake_up_interruptible(&read_wait);
+}
+
+static /*inline*/ int reserve_read_space(int len)
+{
+	int rest = clip_pos - read_pos;
+
+	if(!rest) {
+		read_pos = 0;
+		rest = clip_pos;
+		clip_pos = max_pos;
+	}
+	if(len > rest)
+		len = rest;
+	while(read_pos == write_pos) {
+		interruptible_sleep_on(&read_wait);
+	}
+	rest = write_pos - read_pos;
+	if(rest > 0 && rest < len)
+		len = rest;
+	return len;
+}
+
+static /*inline*/ void read_space(int len)
+{
+	read_pos += len;
+	if(read_pos >= clip_pos) {
+		read_pos = 0;
+		clip_pos = max_pos;
+	}
+	wake_up_interruptible(&write_wait);
+}
+
+static /*inline*/ void init_buffer(char * initxt)
+{
+	int len = initxt ? strlen(initxt) : 0;
+
+	if(!buffer) {
+		buffer = (char*)__get_free_page(GFP_USER);
+		max_pos = clip_pos = PAGE_SIZE;
+	}
+	read_pos = write_pos = 0;
+	memcpy(buffer, initxt, len);
+	write_space(len);
+}
+
+static int omirr_open(struct inode * inode, struct file * file)
+{
+	if(nr_omirr_open)
+		return -EAGAIN;
+	nr_omirr_open++;
+	if(!buffer)
+		init_buffer(NULL);
+	return 0;
+}
+
+static int omirr_release(struct inode * inode, struct file * file)
+{
+	nr_omirr_open--;
+	read_space(0);
+	return 0;
+}
+
+static long omirr_read(struct inode * inode, struct file * file,
+		       char * buf, unsigned long count)
+{
+	char * tmp;
+	int len;
+	int error = 0;
+
+	if(!count)
+		goto done;
+	error = -EINVAL;
+	if(!buf || count < 0)
+		goto done;
+	
+	error = verify_area(VERIFY_WRITE, buf, count);
+	if(error)
+		goto done;
+	
+	error = -EAGAIN;
+	if((file->f_flags & O_NONBLOCK) && read_pos == write_pos)
+		goto done;
+
+	error = len = reserve_read_space(count);
+	tmp = buffer + read_pos;
+	while(len) {
+		put_user(*tmp++, buf++);
+		len--;
+	}
+	read_space(error);
+done:
+	return error;		
+}
+
+int compute_name(struct dentry * entry, char * buf)
+{
+	int len;
+
+	if(IS_ROOT(entry)) {
+		*buf = '/';
+		return 1;
+	}
+	len = compute_name(entry->d_parent, buf);
+	if(len > 1) {
+		buf[len++] = '/';
+	}
+	memcpy(buf+len, entry->d_name, entry->d_len);
+	return len + entry->d_len;
+}
+
+int _omirr_print(struct dentry * ent1, struct dentry * ent2, 
+		struct qstr * suffix, const char * fmt,
+		 va_list args1, va_list args2)
+{
+	int count = strlen(fmt) + 10; /* estimate */
+	const char * tmp = fmt;
+	char lenbuf[8];
+	int res;
+
+	if(!buffer)
+		init_buffer(NULL);
+	while(*tmp) {
+		while(*tmp && *tmp++ != '%') ;
+		if(*tmp) {
+			if(*tmp == 's') {
+				char * str = va_arg(args1, char*);
+				count += strlen(str);
+			} else {
+				(void)va_arg(args1, int);
+				count += 8; /* estimate */
+			}
+		}
+	}
+	if(ent1) {
+		struct dentry * dent = ent1;
+		while(dent && !IS_ROOT(dent)) {
+			count += dent->d_len + 1;
+			dent = dent->d_parent;
+		}
+		count++;
+		if(ent2) {
+			dent = ent2;
+			while(dent && !IS_ROOT(dent)) {
+				count += dent->d_len + 1;
+				dent = dent->d_parent;
+			}
+		count++;
+		}
+		if(suffix)
+			count += suffix->len + 1;
+	}
+	
+	if((nr_omirr_open | cleared_flag) && reserve_write_space(count)) {
+		cleared_flag = 0;
+		res = vsprintf(buffer+write_pos+4, fmt, args2) + 4;
+		if(res > count)
+			printk("omirr: format estimate was wrong\n");
+		if(ent1) {
+			res += compute_name(ent1, buffer+write_pos+res);
+			if(ent2) {
+				buffer[write_pos+res++] = '\0';
+				res += compute_name(ent2, buffer+write_pos+res);
+			}
+			if(suffix) {
+				buffer[write_pos+res++] = '/';
+				memcpy(buffer+write_pos+res,
+				       suffix->name, suffix->len);
+				res += suffix->len;
+			}
+			buffer[write_pos+res++] = '\0';
+			buffer[write_pos+res++] = '\n';
+		}
+		sprintf(lenbuf, "%04d", res);
+		memcpy(buffer+write_pos, lenbuf, 4);
+	} else {
+		if(!cleared_flag) {
+			cleared_flag = 1;
+			init_buffer("0007 Z\n");
+		}
+		res = 0;
+	}
+	write_space(res);
+	return res;
+}
+
+int omirr_print(struct dentry * ent1, struct dentry * ent2, 
+		struct qstr * suffix, const char * fmt, ...)
+{
+	va_list args1, args2;
+	int res;
+
+	/* I don't know whether I could make a simple copy of the va_list,
+	 * so for the safe way...
+	 */
+	va_start(args1, fmt);
+	va_start(args2, fmt);
+	res = _omirr_print(ent1, ent2, suffix, fmt, args1, args2);
+	va_end(args2);
+	va_end(args1);
+	return res;
+}
+
+int omirr_printall(struct inode * inode, const char * fmt, ...)
+{
+	int res = 0;
+	struct dentry * tmp = inode->i_dentry;
+
+	if(tmp) do {
+		va_list args1, args2;
+		va_start(args1, fmt);
+		va_start(args2, fmt);
+		res += _omirr_print(tmp, NULL, NULL, fmt, args1, args2);
+		va_end(args2);
+		va_end(args1);
+		tmp = tmp->d_next;
+	} while(tmp != inode->i_dentry);
+	return res;
+}
+
+static struct file_operations omirr_operations = {
+    NULL,	/* omirr_lseek */
+    omirr_read,
+    NULL,	/* omirr_write */
+    NULL,	/* omirr_readdir */
+    NULL,	/* omirr_select */
+    NULL,	/* omirr_ioctl */
+    NULL,	/* mmap */
+    omirr_open,
+    omirr_release,
+    NULL,	/* fsync */
+    NULL,       /* fasync */
+    NULL,       /* check_media_change */
+    NULL        /* revalidate */
+};
+
+struct inode_operations proc_omirr_inode_operations = {
+    &omirr_operations,
+    NULL, /* create */
+    NULL, /* lookup */
+    NULL, /* link */
+    NULL, /* unlink */
+    NULL, /* symlink */
+    NULL, /* mkdir */
+    NULL, /* rmdir */
+    NULL, /* mknod */
+    NULL, /* rename */
+    NULL, /* readlink */
+    NULL, /* readpage */
+    NULL, /* writepage */
+    NULL, /* bmap */
+    NULL, /* truncate */
+    NULL, /* permission */
+    NULL  /* smap */
+};