Changeset 2b88074b in mainline for uspace/lib/libc/generic/vfs/vfs.c

Timestamp:

2009-10-29T22:06:46Z (14 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

2e983c7

Parents:

14ecd6c

Message:

vfs: file descriptors housekeeping changes

• add support for allocating new file descriptors from the end of the fd range (O_DESC)
• add support for assigning of an already opened file to a free file descriptor

vfs: VFS_OUT_CLOSE is called only when the file reference count is about to drop to zero
vfs: implement VFS_IN_DUP

libc: optimize current working directory housekeeping

• using opendir() was an overkill
• allocate current working directory file descriptor from the end of the fd range using O_DESC (so it doesn't mess with the well-known descriptors 0, 1 and 2)

libc: implement dup2() (via VFS_IN_DUP)

getvc: change stdin/stdout/stderr by a slightly more elegant way (using dup2())

File:

• uspace/lib/libc/generic/vfs/vfs.c (modified) (7 diffs)

uspace/lib/libc/generic/vfs/vfs.c

@@ -57 +57 @@
 static futex_t cwd_futex = FUTEX_INITIALIZER;
 
-DIR *cwd_dir = NULL;
-char *cwd_path = NULL;
-size_t cwd_size = 0;
+static int cwd_fd = -1;
+static char *cwd_path = NULL;
+static size_t cwd_size = 0;
 
 char *absolutize(const char *path, size_t *retlen)
@@ -197 +197 @@
 }
 
-static int _open(const char *path, int lflag, int oflag, ...)
-{
-        ipcarg_t rc;
+static int open_internal(const char *abs, size_t abs_size, int lflag, int oflag)
+{
+        futex_down(&vfs_phone_futex);
+        async_serialize_start();
+        vfs_connect();
+        
         ipc_call_t answer;
-        aid_t req;
-        
-        size_t pa_size;
-        char *pa = absolutize(path, &pa_size);
-        if (!pa)
-                return ENOMEM;
-        
-        futex_down(&vfs_phone_futex);
-        async_serialize_start();
-        vfs_connect();
-        
-        req = async_send_3(vfs_phone, VFS_IN_OPEN, lflag, oflag, 0, &answer);
-        rc = async_data_write_start(vfs_phone, pa, pa_size);
+        aid_t req = async_send_3(vfs_phone, VFS_IN_OPEN, lflag, oflag, 0, &answer);
+        ipcarg_t rc = async_data_write_start(vfs_phone, abs, abs_size);
+        
         if (rc != EOK) {
                 ipcarg_t rc_orig;
-        
-                async_wait_for(req, &rc_orig);
-                async_serialize_end();
-                futex_up(&vfs_phone_futex);
-                free(pa);
-                if (rc_orig == EOK)
-                        return (int) rc;
-                else
-                        return (int) rc_orig;
-        }
-        async_wait_for(req, &rc);
-        async_serialize_end();
-        futex_up(&vfs_phone_futex);
-        free(pa);
+                async_wait_for(req, &rc_orig);
+                
+                async_serialize_end();
+                futex_up(&vfs_phone_futex);
+                
+                if (rc_orig == EOK)
+                        return (int) rc;
+                else
+                        return (int) rc_orig;
+        }
+        
+        async_wait_for(req, &rc);
+        async_serialize_end();
+        futex_up(&vfs_phone_futex);
         
         if (rc != EOK)
@@ -239 +232 @@
 int open(const char *path, int oflag, ...)
 {
-        return _open(path, L_FILE, oflag);
+        size_t abs_size;
+        char *abs = absolutize(path, &abs_size);
+        if (!abs)
+                return ENOMEM;
+        
+        int ret = open_internal(abs, abs_size, L_FILE, oflag);
+        free(abs);
+        
+        return ret;
 }
 
@@ -471 +472 @@
         if (!dirp)
                 return NULL;
-        dirp->fd = _open(dirname, L_DIRECTORY, 0);
-        if (dirp->fd < 0) {
+        
+        size_t abs_size;
+        char *abs = absolutize(dirname, &abs_size);
+        if (!abs) {
+                free(dirp);
+                return ENOMEM;
+        }
+        
+        int ret = open_internal(abs, abs_size, L_DIRECTORY, 0);
+        free(abs);
+        
+        if (ret < 0) {
                 free(dirp);
                 return NULL;
         }
+        
+        dirp->fd = ret;
         return dirp;
 }
@@ -636 +649 @@
 int chdir(const char *path)
 {
-        size_t pa_size;
-        char *pa = absolutize(path, &pa_size);
-        if (!pa)
-                return ENOMEM;
-
-        DIR *d = opendir(pa);
-        if (!d) {
-                free(pa);
+        size_t abs_size;
+        char *abs = absolutize(path, &abs_size);
+        if (!abs)
+                return ENOMEM;
+        
+        int fd = open_internal(abs, abs_size, L_DIRECTORY, O_DESC);
+        
+        if (fd < 0) {
+                free(abs);
                 return ENOENT;
         }
-
+        
         futex_down(&cwd_futex);
-        if (cwd_dir) {
-                closedir(cwd_dir);
-                cwd_dir = NULL;
-                free(cwd_path); 
-                cwd_path = NULL;
-                cwd_size = 0;
-        }
-        cwd_dir = d;
-        cwd_path = pa;
-        cwd_size = pa_size;
+        
+        if (cwd_fd >= 0)
+                close(cwd_fd);
+        
+        
+        if (cwd_path)
+                free(cwd_path);
+        
+        cwd_fd = fd;
+        cwd_path = abs;
+        cwd_size = abs_size;
+        
         futex_up(&cwd_futex);
         return EOK;
@@ -664 +680 @@
 char *getcwd(char *buf, size_t size)
 {
-        if (!cwd_size)
+        if (size == 0)
                 return NULL;
-        if (!size)
-                return NULL;
+        
         futex_down(&cwd_futex);
-        if (size < cwd_size + 1) {
+        
+        if ((cwd_size == 0) || (size < cwd_size + 1)) {
                 futex_up(&cwd_futex);
                 return NULL;
         }
+        
         str_cpy(buf, size, cwd_path);
         futex_up(&cwd_futex);
+        
         return buf;
 }
@@ -707 +725 @@
 }
 
+int dup2(int oldfd, int newfd)
+{
+        futex_down(&vfs_phone_futex);
+        async_serialize_start();
+        vfs_connect();
+        
+        ipcarg_t ret;
+        ipcarg_t rc = async_req_2_1(vfs_phone, VFS_IN_DUP, oldfd, newfd, &ret);
+        
+        async_serialize_end();
+        futex_up(&vfs_phone_futex);
+        
+        if (rc == EOK)
+                return (int) ret;
+        
+        return (int) rc;
+}
+
 /** @}
  */