1 files changed, 111 insertions, 0 deletions

diff --git a/src/fs/pipe.c b/src/fs/pipe.c
new file mode 100644
index 0000000..dfc4480
--- /dev/null
+++ b/src/fs/pipe.c
@@ -0,0 +1,111 @@
+/*
+ *  linux/fs/pipe.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#include <signal.h>
+
+#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)
+{
+        int chars, size, read = 0;
+
+        while (count>0) {
+                while (!(size=PIPE_SIZE(*inode))) {
+                        wake_up(&inode->i_wait);
+                        if (inode->i_count != 2) /* are there any writers? */
+                                return read;
+                        sleep_on(&inode->i_wait);
+                }
+                chars = PAGE_SIZE-PIPE_TAIL(*inode);
+                if (chars > count)
+                        chars = count;
+                if (chars > size)
+                        chars = size;
+                count -= chars;
+                read += chars;
+                size = PIPE_TAIL(*inode);
+                PIPE_TAIL(*inode) += chars;
+                PIPE_TAIL(*inode) &= (PAGE_SIZE-1);
+                while (chars-->0)
+                        put_fs_byte(((char *)inode->i_size)[size++],buf++);
+        }
+        wake_up(&inode->i_wait);
+        return read;
+}
+        
+int write_pipe(struct m_inode * inode, char * buf, int count)
+{
+        int chars, size, written = 0;
+
+        while (count>0) {
+                while (!(size=(PAGE_SIZE-1)-PIPE_SIZE(*inode))) {
+                        wake_up(&inode->i_wait);
+                        if (inode->i_count != 2) { /* no readers */
+                                current->signal |= (1<<(SIGPIPE-1));
+                                return written?written:-1;
+                        }
+                        sleep_on(&inode->i_wait);
+                }
+                chars = PAGE_SIZE-PIPE_HEAD(*inode);
+                if (chars > count)
+                        chars = count;
+                if (chars > size)
+                        chars = size;
+                count -= chars;
+                written += chars;
+                size = PIPE_HEAD(*inode);
+                PIPE_HEAD(*inode) += chars;
+                PIPE_HEAD(*inode) &= (PAGE_SIZE-1);
+                while (chars-->0)
+                        ((char *)inode->i_size)[size++]=get_fs_byte(buf++);
+        }
+        wake_up(&inode->i_wait);
+        return written;
+}
+
+int sys_pipe(unsigned long * fildes)
+{
+        struct m_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++;
+        if (j==1)
+                f[0]->f_count=0;
+        if (j<2)
+                return -1;
+        j=0;
+        for(i=0;j<2 && i<NR_OPEN;i++)
+                if (!current->filp[i]) {
+                        current->filp[ fd[j]=i ] = f[j];
+                        j++;
+                }
+        if (j==1)
+                current->filp[fd[0]]=NULL;
+        if (j<2) {
+                f[0]->f_count=f[1]->f_count=0;
+                return -1;
+        }
+        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;
+        }
+        f[0]->f_inode = f[1]->f_inode = inode;
+        f[0]->f_pos = f[1]->f_pos = 0;
+        f[0]->f_mode = 1;               /* read */
+        f[1]->f_mode = 2;               /* write */
+        put_fs_long(fd[0],0+fildes);
+        put_fs_long(fd[1],1+fildes);
+        return 0;
+}