add ipc pipe (#28)

kernel/ipc/Makefile

@@ -0,0 +1,10 @@
+
+all: pipe.o
+
+CFLAGS += -I .
+
+pipe.o: pipe.c
+	gcc $(CFLAGS) -c pipe.c -o pipe.o
+
+clean:
+	echo "Done."

kernel/ipc/pipe.c

@@ -0,0 +1,162 @@
+#include "pipe.h"
+#include <common/spinlock.h>
+#include <process/process.h>
+#include <process/ptrace.h>
+#include <filesystem/VFS/VFS.h>
+#include <filesystem/fat32/fat32.h>
+#include <common/atomic.h>
+#include <mm/slab.h>
+
+#define MAX_PIPE_BUFF_SIZE  512
+
+struct pipe_t {
+    volatile unsigned int valid_cnt;
+    unsigned int read_pos;
+    unsigned int write_pos;
+    wait_queue_node_t read_wait_queue;
+    wait_queue_node_t write_wait_queue;
+    char buf[MAX_PIPE_BUFF_SIZE];
+    spinlock_t lock;
+};
+
+long pipe_read(struct vfs_file_t *file_ptr, char *buf,
+               int64_t count, long *position)
+{
+    int i = 0;
+    struct pipe_t *pipe_ptr = NULL;
+
+    kdebug("pipe_read into!\n");
+    pipe_ptr = (struct pipe_t *)file_ptr->private_data;
+    spin_lock(&pipe_ptr->lock);
+    while (pipe_ptr->valid_cnt == 0) {
+        /* pipe 空 */
+        kdebug("pipe_read empty!\n");
+        wait_queue_wakeup(&pipe_ptr->write_wait_queue, PROC_UNINTERRUPTIBLE);
+        wait_queue_sleep_on_unlock(&pipe_ptr->read_wait_queue, (void *)&pipe_ptr->lock);
+        spin_lock(&pipe_ptr->lock);
+    }
+    for (i = 0; i < pipe_ptr->valid_cnt; i++) {
+        if (i == count) {
+            break;
+        }
+        copy_to_user(buf + i, &pipe_ptr->buf[pipe_ptr->read_pos], sizeof(char));
+        pipe_ptr->read_pos = (pipe_ptr->read_pos + 1) % MAX_PIPE_BUFF_SIZE;
+    }
+    pipe_ptr->valid_cnt = pipe_ptr->valid_cnt - i;
+    spin_unlock(&pipe_ptr->lock);
+    wait_queue_wakeup(&pipe_ptr->write_wait_queue, PROC_UNINTERRUPTIBLE);
+    kdebug("pipe_read end!\n");
+
+    return i;
+}
+long pipe_write(struct vfs_file_t *file_ptr, char *buf,
+                int64_t count, long *position)
+{
+    int i = 0;
+    struct pipe_t *pipe_ptr = NULL;
+
+    kdebug("pipe_write into!\n");
+    pipe_ptr = (struct pipe_t *)file_ptr->private_data;
+    spin_lock(&pipe_ptr->lock);
+    while (pipe_ptr->valid_cnt + count >= MAX_PIPE_BUFF_SIZE) {
+        /* pipe 满 */
+        kdebug("pipe_write pipe full!\n");
+        wait_queue_wakeup(&pipe_ptr->read_wait_queue, PROC_UNINTERRUPTIBLE);
+        wait_queue_sleep_on_unlock(&pipe_ptr->write_wait_queue, (void *)&pipe_ptr->lock);
+        spin_lock(&pipe_ptr->lock);
+    }
+    for (i = pipe_ptr->valid_cnt; i < MAX_PIPE_BUFF_SIZE; i++) {
+        if (i - pipe_ptr->valid_cnt == count) {
+            break;
+        }
+        copy_from_user(&pipe_ptr->buf[pipe_ptr->write_pos], buf + i, sizeof(char));
+        pipe_ptr->write_pos = (pipe_ptr->write_pos + 1) % MAX_PIPE_BUFF_SIZE;
+    }
+    pipe_ptr->valid_cnt += count;
+    spin_unlock(&pipe_ptr->lock);
+    wait_queue_wakeup(&pipe_ptr->read_wait_queue, PROC_UNINTERRUPTIBLE);
+    kdebug("pipe_write out!\n");
+
+    return count;
+}
+
+long pipe_close(struct vfs_index_node_t *inode, struct vfs_file_t *file_ptr)
+{
+    return 0;
+}
+
+struct vfs_file_operations_t g_pipe_file_ops = {
+    .open       = NULL,
+    .close      = pipe_close,
+    .read       = pipe_read,
+    .write      = pipe_write,
+    .lseek      = NULL,
+    .ioctl      = NULL,
+    .readdir    = NULL,
+};
+
+static struct pipe_t *pipe_alloc()
+{
+    struct pipe_t *pipe_ptr = NULL;
+    
+    pipe_ptr = (struct pipe_t *)kmalloc(sizeof(struct pipe_t), 0);
+    spin_init(&pipe_ptr->lock);
+    pipe_ptr->read_pos  = 0;
+    pipe_ptr->write_pos = 0;
+    pipe_ptr->valid_cnt = 0;
+    memset(pipe_ptr->buf, 0, MAX_PIPE_BUFF_SIZE);
+    wait_queue_init(&pipe_ptr->read_wait_queue, NULL);
+    wait_queue_init(&pipe_ptr->write_wait_queue, NULL);
+
+    return pipe_ptr;
+}
+
+/**
+ * @brief 创建管道
+ *
+ * @param fd(r8) 文件句柄指针
+ * @param num(r9) 文件句柄个数
+ * @return uint64_t 
+ */
+uint64_t sys_pipe(struct pt_regs *regs)
+{
+    int *fd = NULL;
+    struct pipe_t *pipe_ptr = NULL;
+    struct vfs_file_t *read_file = NULL;
+    struct vfs_file_t *write_file = NULL;
+
+    fd = (int *)regs->r8;
+    kdebug("pipe creat into!\n");
+    /* step1 申请pipe结构体、初始化 */
+    pipe_ptr = pipe_alloc();
+    /* step2 申请2个fd文件句柄，1个作为读端、1个作为写端 */
+    read_file = (struct vfs_file_t *)kmalloc(sizeof(struct vfs_file_t), 0);
+    memset(read_file, 0, sizeof(struct vfs_file_t));
+    fd[0] = process_fd_alloc(read_file);
+    if (fd[0] == -1) {
+        kdebug("pipe alloc read fd fail!\n");
+        kfree(pipe_ptr);
+        kfree(read_file);
+        return -1;
+    }
+    write_file = (struct vfs_file_t *)kmalloc(sizeof(struct vfs_file_t), 0);
+    memset(write_file, 0, sizeof(struct vfs_file_t));
+    fd[1] = process_fd_alloc(write_file);
+    if (fd[1] == -1) {
+        kdebug("pipe alloc write fd fail!\n");
+        kfree(pipe_ptr);
+        kfree(read_file);
+        kfree(write_file);
+        return -1;
+    }
+    /* step3 绑定pipe和file */
+    read_file->private_data     = (void *)pipe_ptr;
+    read_file->file_ops         = &g_pipe_file_ops;
+    read_file->mode             = ATTR_READ_ONLY;
+    write_file->private_data    = (void *)pipe_ptr;
+    write_file->file_ops        = &g_pipe_file_ops;
+    write_file->mode            = O_WRONLY;
+    kdebug("pipe creat end!\n");
+
+    return 0;
+}

kernel/ipc/pipe.h

@@ -0,0 +1,4 @@
+#ifndef __PIPE_H__
+#define __PIPE_H__
+
+#endif