feat: implement dup(2), dup2(2)

[lunaix-os.git] / lunaix-os / kernel / fs / vfs.c

diff --git a/lunaix-os/kernel/fs/vfs.c b/lunaix-os/kernel/fs/vfs.c
index 51ef5c9827f6612313564609f2d47029fa2c4c74..05741d846f15df903cca7e9b524acce835eb5112 100644 (file)
--- a/lunaix-os/kernel/fs/vfs.c
+++ b/lunaix-os/kernel/fs/vfs.c
@@ -37,6 +37,10 @@ static struct hbucket* dnode_cache;
 
 static int fs_id = 0;
 
 
 static int fs_id = 0;
 

+struct hstr vfs_ddot = HSTR("..", 2);
+struct hstr vfs_dot = HSTR(".", 1);
+struct hstr vfs_empty = HSTR("", 0);
+

 struct v_dnode*
 vfs_d_alloc();
 
 struct v_dnode*
 vfs_d_alloc();
 


@@ -62,6 +66,9 @@ vfs_init()
 
     dnode_cache = vzalloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket));
 
 
     dnode_cache = vzalloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket));
 

+    hstr_rehash(&vfs_ddot, HSTR_FULL_HASH);
+    hstr_rehash(&vfs_dot, HSTR_FULL_HASH);
+

     // 创建一个根superblock，用来蕴含我们的根目录。
     root_sb = vfs_sb_alloc();
     root_sb->root = vfs_d_alloc();
     // 创建一个根superblock，用来蕴含我们的根目录。
     root_sb = vfs_sb_alloc();
     root_sb->root = vfs_d_alloc();


@@ -80,9 +87,13 @@ __dcache_get_bucket(struct v_dnode* parent, unsigned int hash)
 struct v_dnode*
 vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
 {
 struct v_dnode*
 vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
 {

-    if (!str->len)
+    if (!str->len || HSTR_EQ(str, &vfs_dot))

         return parent;
 
         return parent;
 

+    if (HSTR_EQ(str, &vfs_ddot)) {
+        return parent->parent ? parent->parent : parent;
+    }
+

     struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
 
     struct v_dnode *pos, *n;
     struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
 
     struct v_dnode *pos, *n;


@@ -165,8 +176,7 @@ vfs_walk(struct v_dnode* start,
 
         if (!dnode) {
             dnode = vfs_d_alloc();
 
         if (!dnode) {
             dnode = vfs_d_alloc();

-            dnode->name = HSTR(valloc(VFS_NAME_MAXLEN), j);
-            dnode->name.hash = name.hash;
+            dnode->name = HHSTR(valloc(VFS_NAME_MAXLEN), j, name.hash);

 
             strcpy(dnode->name.value, name_content);
 
 
             strcpy(dnode->name.value, name_content);
 


@@ -204,6 +214,7 @@ vfs_walk(struct v_dnode* start,
 error:
     vfree(dnode->name.value);
     vfs_d_free(dnode);
 error:
     vfree(dnode->name.value);
     vfs_d_free(dnode);

+    *dentry = NULL;

     return errno;
 }
 
     return errno;
 }
 


@@ -281,6 +292,10 @@ vfs_open(struct v_dnode* dnode, struct v_file** file)
     struct v_file* vfile = cake_grab(file_pile);
     memset(vfile, 0, sizeof(*vfile));
 
     struct v_file* vfile = cake_grab(file_pile);
     memset(vfile, 0, sizeof(*vfile));
 

+    vfile->dnode = dnode;
+    vfile->inode = dnode->inode;
+    dnode->inode->open_count++;
+

     int errno = dnode->inode->ops.open(dnode->inode, vfile);
     if (errno) {
         cake_release(file_pile, vfile);
     int errno = dnode->inode->ops.open(dnode->inode, vfile);
     if (errno) {
         cake_release(file_pile, vfile);


@@ -290,6 +305,22 @@ vfs_open(struct v_dnode* dnode, struct v_file** file)
     return errno;
 }
 
     return errno;
 }
 

+int
+vfs_link(struct v_dnode* to_link, struct v_dnode* name)
+{
+    int errno;
+    if (to_link->super_block->root != name->super_block->root) {
+        errno = EXDEV;
+    } else if (!to_link->inode->ops.link) {
+        errno = ENOTSUP;
+    } else if (!(errno = to_link->inode->ops.link(to_link->inode, name))) {
+        name->inode = to_link->inode;
+        to_link->inode->link_count++;
+    }
+
+    return errno;
+}
+

 int
 vfs_close(struct v_file* file)
 {
 int
 vfs_close(struct v_file* file)
 {


@@ -299,6 +330,9 @@ vfs_close(struct v_file* file)
 
     int errno = file->ops.close(file);
     if (!errno) {
 
     int errno = file->ops.close(file);
     if (!errno) {

+        if (file->inode->open_count) {
+            file->inode->open_count--;
+        }

         cake_release(file_pile, file);
     }
     return errno;
         cake_release(file_pile, file);
     }
     return errno;


@@ -348,7 +382,10 @@ struct v_dnode*
 vfs_d_alloc()
 {
     struct v_dnode* dnode = cake_grab(dnode_pile);
 vfs_d_alloc()
 {
     struct v_dnode* dnode = cake_grab(dnode_pile);

+    memset(dnode, 0, sizeof(*dnode));

     llist_init_head(&dnode->children);
     llist_init_head(&dnode->children);

+    dnode->name = vfs_empty;
+    return dnode;

 }
 
 void
 }
 
 void


@@ -375,55 +412,87 @@ vfs_i_free(struct v_inode* inode)
     cake_release(inode_pile, inode);
 }
 
     cake_release(inode_pile, inode);
 }
 

-__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+/* ---- System call definition and support ---- */
+
+#define FLOCATE_CREATE_EMPTY 1
+
+#define DO_STATUS(errno) SYSCALL_ESTATUS(__current->k_status = errno)
+
+int
+__vfs_try_locate_file(const char* path,
+                      struct v_dnode** fdir,
+                      struct v_dnode** file,
+                      int options)

 {
     char name_str[VFS_NAME_MAXLEN];
     struct hstr name = HSTR(name_str, 0);
 {
     char name_str[VFS_NAME_MAXLEN];
     struct hstr name = HSTR(name_str, 0);

-    struct v_dnode *dentry, *file;
-    int errno, fd;
-    if ((errno = vfs_walk(NULL, path, &dentry, &name, VFS_WALK_PARENT))) {
-        return -1;
+    int errno;
+    if (!(errno = vfs_walk(NULL, path, fdir, &name, VFS_WALK_PARENT))) {
+        errno = vfs_walk(*fdir, name.value, file, NULL, 0);
+        if (errno == ENOENT && (options & FLOCATE_CREATE_EMPTY)) {
+            struct v_dnode* file_new;
+            file_new = vfs_d_alloc();
+            file_new->name =
+              HHSTR(valloc(VFS_NAME_MAXLEN), name.len, name.hash);
+            strcpy(file_new->name.value, name_str);
+            *file = file_new;
+
+            llist_append(&(*fdir)->children, &file_new->siblings);
+        }

     }
 
     }
 

-    vfs_walk(dentry, name.value, &file, NULL, 0);
+    return errno;
+}

 
 

+int
+__vfs_do_open(struct v_file** file_out, const char* path, int options)
+{
+    int errno;
+    struct v_dnode *dentry, *file;

     struct v_file* opened_file = 0;
     struct v_file* opened_file = 0;

-    if (!file) {
-        if ((options & FO_CREATE)) {
-            errno = dentry->inode->ops.create(dentry->inode, opened_file);
-        } else {
-            errno = ENOENT;
-        }
-    } else {
+
+    errno = __vfs_try_locate_file(path, &dentry, &file, 0);
+
+    if (errno != ENOENT && (options & FO_CREATE)) {
+        errno = dentry->inode->ops.create(dentry->inode, opened_file);
+    } else if (!errno) {

         errno = vfs_open(file, &opened_file);
     }
 
         errno = vfs_open(file, &opened_file);
     }
 

-    __current->k_status = errno;
+    *file_out = opened_file;
+    return errno;
+}
+
+__DEFINE_LXSYSCALL2(int, open, const char*, path, int, options)
+{
+    struct v_file* opened_file;
+    int errno = __vfs_do_open(&opened_file, path, options), fd;

 
     if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = vzalloc(sizeof(*fd_s));
         fd_s->file = opened_file;
 
     if (!errno && !(errno = vfs_alloc_fdslot(&fd))) {
         struct v_fd* fd_s = vzalloc(sizeof(*fd_s));
         fd_s->file = opened_file;

-        fd_s->pos = file->inode->fsize & -((options & FO_APPEND) == 0);
+        fd_s->pos = opened_file->inode->fsize & -((options & FO_APPEND) != 0);

         __current->fdtable->fds[fd] = fd_s;
         __current->fdtable->fds[fd] = fd_s;

+        return fd;

     }
 
     }
 

-    return SYSCALL_ESTATUS(errno);
+    return DO_STATUS(errno);

 }
 }

+#define TEST_FD(fd) (fd >= 0 && fd < VFS_MAX_FD)
+#define GET_FD(fd, fd_s) (TEST_FD(fd) && (fd_s = __current->fdtable->fds[fd]))

 
 __DEFINE_LXSYSCALL1(int, close, int, fd)
 {
     struct v_fd* fd_s;
     int errno;
 
 __DEFINE_LXSYSCALL1(int, close, int, fd)
 {
     struct v_fd* fd_s;
     int errno;

-    if (fd < 0 || fd >= VFS_MAX_FD || !(fd_s = __current->fdtable->fds[fd])) {
+    if (!GET_FD(fd, fd_s)) {

         errno = EBADF;
     } else if (!(errno = vfs_close(fd_s->file))) {
         vfree(fd_s);
         __current->fdtable->fds[fd] = 0;
     }
 
         errno = EBADF;
     } else if (!(errno = vfs_close(fd_s->file))) {
         vfree(fd_s);
         __current->fdtable->fds[fd] = 0;
     }
 

-    __current->k_status = errno;
-
-    return SYSCALL_ESTATUS(errno);
+    return DO_STATUS(errno);

 }
 
 void
 }
 
 void


@@ -442,7 +511,7 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
 {
     struct v_fd* fd_s;
     int errno;
 {
     struct v_fd* fd_s;
     int errno;

-    if (fd < 0 || fd >= VFS_MAX_FD || !(fd_s = __current->fdtable->fds[fd])) {
+    if (!GET_FD(fd, fd_s)) {

         errno = EBADF;
     } else if (!(fd_s->file->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;
         errno = EBADF;
     } else if (!(fd_s->file->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;


@@ -452,13 +521,22 @@ __DEFINE_LXSYSCALL2(int, readdir, int, fd, struct dirent*, dent)
                                 .index = dent->d_offset,
                                 .read_complete_callback =
                                   __vfs_readdir_callback };
                                 .index = dent->d_offset,
                                 .read_complete_callback =
                                   __vfs_readdir_callback };

-        if (!(errno = fd_s->file->ops.readdir(fd_s->file, &dctx))) {
-            dent->d_offset++;
+        if (dent->d_offset == 0) {
+            __vfs_readdir_callback(&dctx, vfs_dot.value, vfs_dot.len, 0);
+        } else if (dent->d_offset == 1) {
+            __vfs_readdir_callback(&dctx, vfs_ddot.value, vfs_ddot.len, 0);
+        } else {
+            dctx.index -= 2;
+            if ((errno = fd_s->file->ops.readdir(fd_s->file, &dctx))) {
+                goto done;
+            }

         }
         }

+        errno = 0;
+        dent->d_offset++;

     }
 
     }
 

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+done:
+    return DO_STATUS(errno);

 }
 
 __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
 }
 
 __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)


@@ -470,7 +548,9 @@ __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
         goto done;
     }
 
         goto done;
     }
 

-    if (!parent->inode->ops.mkdir) {
+    if ((parent->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = ENOTSUP;
+    } else if (!parent->inode->ops.mkdir) {

         errno = ENOTSUP;
     } else if (!(parent->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;
         errno = ENOTSUP;
     } else if (!(parent->inode->itype & VFS_INODE_TYPE_DIR)) {
         errno = ENOTDIR;


@@ -486,16 +566,307 @@ __DEFINE_LXSYSCALL1(int, mkdir, const char*, path)
     }
 
 done:
     }
 
 done:

-    __current->k_status = errno;
-    return SYSCALL_ESTATUS(errno);
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, read, int, fd, void*, buf, size_t, count)
+{
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_file* file = fd_s->file;
+        file->f_pos = fd_s->pos;
+        if ((errno = file->ops.read(file, buf, count)) >= 0) {
+            fd_s->pos += errno;
+        }
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, write, int, fd, void*, buf, size_t, count)
+{
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_file* file = fd_s->file;
+        file->f_pos = fd_s->pos;
+        if ((errno = file->ops.write(file, buf, count)) >= 0) {
+            fd_s->pos += errno;
+        }
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL3(int, lseek, int, fd, int, offset, int, options)
+{
+    int errno = 0;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        size_t fpos = fd_s->file->f_pos;
+        switch (options) {
+            case FSEEK_CUR:
+                fpos = (size_t)((int)fd_s->file->f_pos + offset);
+                break;
+            case FSEEK_END:
+                fpos = (size_t)((int)fd_s->file->inode->fsize + offset);
+                break;
+            case FSEEK_SET:
+                fpos = offset;
+                break;
+
+            default:
+                break;
+        }
+        fd_s->pos = fpos;
+    }
+
+    return DO_STATUS(errno);
+}
+
+int
+vfs_readlink(struct v_dnode* dnode, char* buf, size_t size, int depth)
+{
+    if (!dnode) {
+        return 0;
+    }
+
+    if (depth > 64) {
+        return ELOOP;
+    }
+
+    size_t len = vfs_readlink(dnode->parent, buf, size, depth + 1);
+
+    if (len >= size) {
+        return len;
+    }
+
+    size_t cpy_size = MIN(dnode->name.len, size - len);
+    strncpy(buf + len, dnode->name.value, cpy_size);
+    len += cpy_size;
+
+    if (len < size) {
+        buf[len++] = PATH_DELIM;
+    }
+
+    return len;
+}
+
+__DEFINE_LXSYSCALL3(int, readlink, const char*, path, char*, buf, size_t, size)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if (!(errno = vfs_walk(NULL, path, &dnode, NULL, 0))) {
+        errno = vfs_readlink(dnode, buf, size, 0);
+    }
+
+    if (errno >= 0) {
+        return errno;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL4(int,
+                    readlinkat,
+                    int,
+                    dirfd,
+                    const char*,
+                    pathname,
+                    char*,
+                    buf,
+                    size_t,
+                    size)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(dirfd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_dnode* dnode;
+        if (!(errno = vfs_walk(fd_s->file->dnode, pathname, &dnode, NULL, 0))) {
+            errno = vfs_readlink(fd_s->file->dnode, buf, size, 0);
+        }
+    }
+
+    if (errno >= 0) {
+        return errno;
+    }
+
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, rmdir, const char*, pathname)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if ((errno = vfs_walk(NULL, pathname, &dnode, NULL, 0))) {
+        goto done;
+    }
+    if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = EROFS;
+        goto done;
+    }
+
+    if (dnode->inode->open_count) {
+        errno = EBUSY;
+        goto done;
+    }
+
+    if ((dnode->inode->itype & VFS_INODE_TYPE_DIR)) {
+        errno = dnode->inode->ops.rmdir(dnode->inode);
+    } else {
+        errno = ENOTDIR;
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+int
+__vfs_do_unlink(struct v_inode* inode)
+{
+    int errno;
+    if (inode->open_count) {
+        errno = EBUSY;
+    } else if (!(inode->itype & VFS_INODE_TYPE_DIR)) {
+        // TODO handle symbolic link and type other than regular file
+        errno = inode->ops.unlink(inode);
+        if (!errno) {
+            inode->link_count--;
+        }
+    } else {
+        errno = EISDIR;
+    }
+
+    return errno;
+}
+
+__DEFINE_LXSYSCALL1(int, unlink, const char*, pathname)
+{
+    int errno;
+    struct v_dnode* dnode;
+    if ((errno = vfs_walk(NULL, pathname, &dnode, NULL, 0))) {
+        goto done;
+    }
+    if ((dnode->super_block->fs->types & FSTYPE_ROFS)) {
+        errno = EROFS;
+        goto done;
+    }
+
+    errno = __vfs_do_unlink(dnode->inode);
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, unlinkat, int, fd, const char*, pathname)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(fd, fd_s)) {
+        errno = EBADF;
+    } else {
+        struct v_dnode* dnode;
+        if (!(errno = vfs_walk(fd_s->file->dnode, pathname, &dnode, NULL, 0))) {
+            errno = __vfs_do_unlink(dnode->inode);
+        }
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL2(int, link, const char*, oldpath, const char*, newpath)
+{
+    int errno;
+    struct v_dnode *dentry, *to_link, *name_dentry, *name_file;
+
+    errno = __vfs_try_locate_file(oldpath, &dentry, &to_link, 0);
+    if (!errno) {
+        errno = __vfs_try_locate_file(
+          newpath, &name_dentry, &name_file, FLOCATE_CREATE_EMPTY);
+        if (!errno) {
+            errno = EEXIST;
+        } else if (name_file) {
+            errno = vfs_link(to_link, name_file);
+        }
+    }
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, fsync, int, fildes)
+{
+    int errno;
+    struct v_fd* fd_s;
+    if (!GET_FD(fildes, fd_s)) {
+        errno = EBADF;
+    } else {
+        errno = vfs_fsync(fd_s->file);
+    }
+
+    return DO_STATUS(errno);

 }
 
 }
 

-__DEFINE_LXSYSCALL3(size_t, read, int, fd, void*, buf, size_t, count)
+int
+__vfs_dup_fd(struct v_fd* old, struct v_fd** new)

 {
 {

-    // TODO
+    int errno = 0;
+    struct v_file* newopened;
+    if (!(errno = vfs_open(old->file->dnode, &newopened))) {
+        *new = cake_grab(fd_pile);
+        **new = (struct v_fd){ .file = newopened,
+                               .pos = old->pos,
+                               .flags = old->flags };
+    }
+
+    return errno;

 }
 
 }
 

-__DEFINE_LXSYSCALL3(size_t, write, int, fd, void*, buf, size_t, count)
+__DEFINE_LXSYSCALL2(int, dup2, int, oldfd, int, newfd)

 {
 {

-    // TODO
+    if (newfd == oldfd) {
+        return newfd;
+    }
+
+    int errno;
+    struct v_fd *oldfd_s, *newfd_s;
+    if (!GET_FD(oldfd, oldfd_s) || TEST_FD(newfd)) {
+        errno = EBADF;
+        goto done;
+    }
+    newfd_s = __current->fdtable->fds[newfd];
+    if (newfd_s && (errno = vfs_close(newfd_s))) {
+        goto done;
+    }
+
+    if (!(errno = __vfs_dup_fd(oldfd_s, &newfd_s))) {
+        __current->fdtable->fds[newfd] = newfd_s;
+        return newfd;
+    }
+
+done:
+    return DO_STATUS(errno);
+}
+
+__DEFINE_LXSYSCALL1(int, dup, int, oldfd)
+{
+    int errno, newfd;
+    struct v_fd *oldfd_s, *newfd_s;
+    if (!GET_FD(oldfd, oldfd_s)) {
+        errno = EBADF;
+    } else if (!(errno = vfs_alloc_fdslot(&newfd)) &&
+               !(errno = __vfs_dup_fd(oldfd_s, &newfd_s))) {
+        __current->fdtable->fds[newfd] = newfd_s;
+        return newfd;
+    }
+
+    return DO_STATUS(errno);

 }
\ No newline at end of file
 }
\ No newline at end of file