--- linux/fs/pipe.c	2018/04/24 18:00:41	1.1
+++ linux/fs/pipe.c	2018/04/24 18:12:09	1.1.1.9
@@ -1,69 +1,219 @@
-#include <signal.h>
+/*
+ *  linux/fs/pipe.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
 
-#include <linux/sched.h>
-#include <linux/mm.h>	/* for get_free_page */
 #include <asm/segment.h>
 
-int read_pipe(struct m_inode * inode, char * buf, int count)
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/fcntl.h>
+#include <linux/termios.h>
+
+static int pipe_read(struct inode * inode, struct file * filp, char * buf, int count)
 {
-	char * b=buf;
+	int chars, size, read = 0;
 
-	while (PIPE_EMPTY(*inode)) {
-		wake_up(&inode->i_wait);
-		if (inode->i_count != 2) /* are there any writers left? */
-			return 0;
-		sleep_on(&inode->i_wait);
-	}
-	while (count>0 && !(PIPE_EMPTY(*inode))) {
-		count --;
-		put_fs_byte(((char *)inode->i_size)[PIPE_TAIL(*inode)],b++);
-		INC_PIPE( PIPE_TAIL(*inode) );
+	if (!(filp->f_flags & O_NONBLOCK))
+		while (!PIPE_SIZE(*inode)) {
+			wake_up(& PIPE_WRITE_WAIT(*inode));
+			if (!PIPE_WRITERS(*inode)) /* are there any writers? */
+				return 0;
+			if (current->signal & ~current->blocked)
+				return -ERESTARTSYS;
+			interruptible_sleep_on(& PIPE_READ_WAIT(*inode));
+		}
+	while (count>0 && (size = PIPE_SIZE(*inode))) {
+		chars = PAGE_SIZE-PIPE_TAIL(*inode);
+		if (chars > count)
+			chars = count;
+		if (chars > size)
+			chars = size;
+		memcpy_tofs(buf, (char *)inode->i_size+PIPE_TAIL(*inode), chars );
+		read += chars;
+		PIPE_TAIL(*inode) += chars;
+		PIPE_TAIL(*inode) &= (PAGE_SIZE-1);
+		count -= chars;
+		buf += chars;
 	}
-	wake_up(&inode->i_wait);
-	return b-buf;
+	wake_up(& PIPE_WRITE_WAIT(*inode));
+	return read?read:-EAGAIN;
 }
 	
-int write_pipe(struct m_inode * inode, char * buf, int count)
+static int pipe_write(struct inode * inode, struct file * filp, char * buf, int count)
 {
-	char * b=buf;
+	int chars, size, written = 0;
 
-	wake_up(&inode->i_wait);
-	if (inode->i_count != 2) { /* no readers */
-		current->signal |= (1<<(SIGPIPE-1));
-		return -1;
-	}
-	while (count-->0) {
-		while (PIPE_FULL(*inode)) {
-			wake_up(&inode->i_wait);
-			if (inode->i_count != 2) {
-				current->signal |= (1<<(SIGPIPE-1));
-				return b-buf;
+	if (!PIPE_READERS(*inode)) { /* no readers */
+		send_sig(SIGPIPE,current,0);
+		return -EPIPE;
+	}
+/* if count < PAGE_SIZE, we have to make it atomic */
+	if (count < PAGE_SIZE)
+		size = PAGE_SIZE-count;
+	else
+		size = PAGE_SIZE-1;
+	while (count>0) {
+		while (PIPE_SIZE(*inode) >= size) {
+			if (!PIPE_READERS(*inode)) { /* no readers */
+				send_sig(SIGPIPE,current,0);
+				return written?written:-EPIPE;
 			}
-			sleep_on(&inode->i_wait);
+			if (current->signal & ~current->blocked)
+				return written?written:-ERESTARTSYS;
+			if (filp->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+			else
+				interruptible_sleep_on(&PIPE_WRITE_WAIT(*inode));
+		}
+		while (count>0 && (size = (PAGE_SIZE-1)-PIPE_SIZE(*inode))) {
+			chars = PAGE_SIZE-PIPE_HEAD(*inode);
+			if (chars > count)
+				chars = count;
+			if (chars > size)
+				chars = size;
+			memcpy_fromfs((char *)inode->i_size+PIPE_HEAD(*inode), buf, chars );
+			written += chars;
+			PIPE_HEAD(*inode) += chars;
+			PIPE_HEAD(*inode) &= (PAGE_SIZE-1);
+			count -= chars;
+			buf += chars;
 		}
-		((char *)inode->i_size)[PIPE_HEAD(*inode)] = get_fs_byte(b++);
-		INC_PIPE( PIPE_HEAD(*inode) );
-		wake_up(&inode->i_wait);
+		wake_up(& PIPE_READ_WAIT(*inode));
+		size = PAGE_SIZE-1;
 	}
-	wake_up(&inode->i_wait);
-	return b-buf;
+	return written;
+}
+
+static int pipe_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
+{
+	return -ESPIPE;
 }
 
+static int pipe_readdir(struct inode * inode, struct file * file, struct dirent * de, int count)
+{
+	return -ENOTDIR;
+}
+
+static int bad_pipe_rw(struct inode * inode, struct file * filp, char * buf, int count)
+{
+	return -EBADF;
+}
+
+static int pipe_ioctl(struct inode *pino, struct file * filp,
+	unsigned int cmd, unsigned int arg)
+{
+	switch (cmd) {
+		case FIONREAD:
+			verify_area((void *) arg,4);
+			put_fs_long(PIPE_SIZE(*pino),(unsigned long *) arg);
+			return 0;
+		default:
+			return -EINVAL;
+	}
+}
+
+static int pipe_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait)
+{
+	switch (sel_type) {
+		case SEL_IN:
+			if (!PIPE_EMPTY(*inode) || !PIPE_WRITERS(*inode))
+				return 1;
+			select_wait(&PIPE_READ_WAIT(*inode), wait);
+			return 0;
+		case SEL_OUT:
+			if (!PIPE_FULL(*inode) || !PIPE_WRITERS(*inode))
+				return 1;
+			select_wait(&PIPE_WRITE_WAIT(*inode), wait);
+			return 0;
+		case SEL_EX:
+			if (!PIPE_READERS(*inode) || !PIPE_WRITERS(*inode))
+				return 1;
+			select_wait(&inode->i_wait,wait);
+			return 0;
+	}
+	return 0;
+}
+
+/*
+ * Ok, these three routines NOW keep track of readers/writers,
+ * Linus previously did it with inode->i_count checking.
+ */
+static void pipe_read_release(struct inode * inode, struct file * filp)
+{
+	PIPE_READERS(*inode)--;
+	wake_up(&PIPE_WRITE_WAIT(*inode));
+}
+
+static void pipe_write_release(struct inode * inode, struct file * filp)
+{
+	PIPE_WRITERS(*inode)--;
+	wake_up(&PIPE_READ_WAIT(*inode));
+}
+
+static void pipe_rdwr_release(struct inode * inode, struct file * filp)
+{
+	PIPE_READERS(*inode)--;
+	PIPE_WRITERS(*inode)--;
+	wake_up(&PIPE_READ_WAIT(*inode));
+	wake_up(&PIPE_WRITE_WAIT(*inode));
+}
+
+/*
+ * The three file_operations structs are not static because they
+ * are also used in linux/fs/fifo.c to do operations on fifo's.
+ */
+struct file_operations read_pipe_fops = {
+	pipe_lseek,
+	pipe_read,
+	bad_pipe_rw,
+	pipe_readdir,
+	pipe_select,
+	pipe_ioctl,
+	NULL,		/* no special open code */
+	pipe_read_release
+};
+
+struct file_operations write_pipe_fops = {
+	pipe_lseek,
+	bad_pipe_rw,
+	pipe_write,
+	pipe_readdir,
+	pipe_select,
+	pipe_ioctl,
+	NULL,		/* no special open code */
+	pipe_write_release
+};
+
+struct file_operations rdwr_pipe_fops = {
+	pipe_lseek,
+	pipe_read,
+	pipe_write,
+	pipe_readdir,
+	pipe_select,
+	pipe_ioctl,
+	NULL,		/* no special open code */
+	pipe_rdwr_release
+};
+
 int sys_pipe(unsigned long * fildes)
 {
-	struct m_inode * inode;
+	struct inode * inode;
 	struct file * f[2];
 	int fd[2];
 	int i,j;
 
-	j=0;
-	for(i=0;j<2 && i<NR_FILE;i++)
-		if (!file_table[i].f_count)
-			(f[j++]=i+file_table)->f_count++;
+	verify_area(fildes,8);
+	for(j=0 ; j<2 ; j++)
+		if (!(f[j] = get_empty_filp()))
+			break;
 	if (j==1)
-		f[0]->f_count=0;
+		f[0]->f_count--;
 	if (j<2)
-		return -1;
+		return -ENFILE;
 	j=0;
 	for(i=0;j<2 && i<NR_OPEN;i++)
 		if (!current->filp[i]) {
@@ -73,18 +223,23 @@ int sys_pipe(unsigned long * fildes)
 	if (j==1)
 		current->filp[fd[0]]=NULL;
 	if (j<2) {
-		f[0]->f_count=f[1]->f_count=0;
-		return -1;
+		f[0]->f_count--;
+		f[1]->f_count--;
+		return -EMFILE;
 	}
 	if (!(inode=get_pipe_inode())) {
-		current->filp[fd[0]] =
-			current->filp[fd[1]] = NULL;
-		f[0]->f_count = f[1]->f_count = 0;
-		return -1;
+		current->filp[fd[0]] = NULL;
+		current->filp[fd[1]] = NULL;
+		f[0]->f_count--;
+		f[1]->f_count--;
+		return -ENFILE;
 	}
 	f[0]->f_inode = f[1]->f_inode = inode;
 	f[0]->f_pos = f[1]->f_pos = 0;
+	f[0]->f_flags = f[1]->f_flags = 0;
+	f[0]->f_op = &read_pipe_fops;
 	f[0]->f_mode = 1;		/* read */
+	f[1]->f_op = &write_pipe_fops;
 	f[1]->f_mode = 2;		/* write */
 	put_fs_long(fd[0],0+fildes);
 	put_fs_long(fd[1],1+fildes);