patch-2.3.6 linux/fs/proc/sysvipc.c

• Lines: 139
• Date: Mon Jun 7 12:20:50 1999
• Orig file: v2.3.5/linux/fs/proc/sysvipc.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.5/linux/fs/proc/sysvipc.c linux/fs/proc/sysvipc.c
@@ -0,0 +1,138 @@
+/*
+ *  linux/fs/proc/sysvipc.c
+ *
+ *  Copyright (c) 1999 Dragos Acostachioaie
+ *
+ *  This code is derived from linux/fs/proc/generic.c,
+ *  which is Copyright (C) 1991, 1992 Linus Torvalds.
+ *
+ *  /proc/sysvipc directory handling functions
+ */
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+
+#include <asm/uaccess.h>
+
+#ifndef MIN
+#define MIN(a,b) (((a) < (b)) ? (a) : (b))
+#endif
+
+/* 4K page size but our output routines use some slack for overruns */
+#define PROC_BLOCK_SIZE	(3*1024)
+
+static ssize_t
+proc_sysvipc_read(struct file * file, char * buf, size_t nbytes, loff_t *ppos)
+{
+	struct inode * inode = file->f_dentry->d_inode;
+	char 	*page;
+	ssize_t	retval=0;
+	int	eof=0;
+	ssize_t	n, count;
+	char	*start;
+	struct proc_dir_entry * dp;
+
+	dp = (struct proc_dir_entry *) inode->u.generic_ip;
+	if (!(page = (char*) __get_free_page(GFP_KERNEL)))
+		return -ENOMEM;
+
+	while ((nbytes > 0) && !eof)
+	{
+		count = MIN(PROC_BLOCK_SIZE, nbytes);
+
+		start = NULL;
+		if (dp->get_info) {
+			/*
+			 * Handle backwards compatibility with the old net
+			 * routines.
+			 * 
+			 * XXX What gives with the file->f_flags & O_ACCMODE
+			 * test?  Seems stupid to me....
+			 */
+			n = dp->get_info(page, &start, *ppos, count,
+				 (file->f_flags & O_ACCMODE) == O_RDWR);
+			if (n < count)
+				eof = 1;
+		} else if (dp->read_proc) {
+			n = dp->read_proc(page, &start, *ppos,
+					  count, &eof, dp->data);
+		} else
+			break;
+			
+		if (!start) {
+			/*
+			 * For proc files that are less than 4k
+			 */
+			start = page + *ppos;
+			n -= *ppos;
+			if (n <= 0)
+				break;
+			if (n > count)
+				n = count;
+		}
+		if (n == 0)
+			break;	/* End of file */
+		if (n < 0) {
+			if (retval == 0)
+				retval = n;
+			break;
+		}
+		
+		/* This is a hack to allow mangling of file pos independent
+ 		 * of actual bytes read.  Simply place the data at page,
+ 		 * return the bytes, and set `start' to the desired offset
+ 		 * as an unsigned int. - Paul.Russell@rustcorp.com.au
+		 */
+ 		n -= copy_to_user(buf, start < page ? page : start, n);
+		if (n == 0) {
+			if (retval == 0)
+				retval = -EFAULT;
+			break;
+		}
+
+		*ppos += start < page ? (long)start : n; /* Move down the file */
+		nbytes -= n;
+		buf += n;
+		retval += n;
+	}
+	free_page((unsigned long) page);
+	return retval;
+}
+
+static struct file_operations proc_sysvipc_operations = {
+    NULL,		/* lseek   */
+    proc_sysvipc_read,	/* read	   */
+    NULL,		/* write   */
+    NULL,		/* readdir */
+    NULL,		/* poll    */
+    NULL,		/* ioctl   */
+    NULL,		/* mmap	   */
+    NULL,		/* no special open code	   */
+    NULL,		/* no special release code */
+    NULL		/* can't fsync */
+};
+
+/*
+ * proc directories can do almost nothing..
+ */
+struct inode_operations proc_sysvipc_inode_operations = {
+	&proc_sysvipc_operations,	/* default net file-ops */
+	NULL,				/* create */
+	NULL,				/* lookup */
+	NULL,				/* link */
+	NULL,				/* unlink */
+	NULL,				/* symlink */
+	NULL,				/* mkdir */
+	NULL,				/* rmdir */
+	NULL,				/* mknod */
+	NULL,				/* rename */
+	NULL,				/* readlink */
+	NULL,				/* follow_link */
+	NULL,				/* readpage */
+	NULL,				/* writepage */
+	NULL,				/* bmap */
+	NULL,				/* truncate */
+	NULL				/* permission */
+};