Changeset 2b88074b in mainline for uspace/app/getvc/getvc.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/app/getvc/getvc.c (modified) (4 diffs)

uspace/app/getvc/getvc.c

@@ -36 +36 @@
 
 #include <sys/types.h>
+#include <fcntl.h>
 #include <unistd.h>
 #include <stdio.h>
@@ -46 +47 @@
 }
 
-static void closeall(void)
+static void reopen(FILE **stream, int fd, const char *path, int flags, const char *mode)
 {
-        fclose(stdin);
-        fclose(stdout);
-        fclose(stderr);
+        if (fclose(*stream))
+                return;
         
-        close(0);
-        close(1);
-        close(2);
+        *stream = NULL;
+        
+        int oldfd = open(path, flags);
+        if (oldfd < 0)
+                return;
+        
+        if (oldfd != fd) {
+                if (dup2(oldfd, fd) != fd)
+                        return;
+                
+                if (close(oldfd))
+                        return;
+        }
+        
+        *stream = fdopen(fd, mode);
 }
 
@@ -74 +86 @@
 int main(int argc, char *argv[])
 {
-        task_exit_t texit;
-        int retval;
-
         if (argc < 3) {
                 usage();
@@ -82 +91 @@
         }
         
-        closeall();
+        reopen(&stdin, 0, argv[1], O_RDONLY, "r");
+        reopen(&stdout, 1, argv[1], O_WRONLY, "w");
+        reopen(&stderr, 2, argv[1], O_WRONLY, "w");
         
-        stdin = fopen(argv[1], "r");
-        stdout = fopen(argv[1], "w");
-        stderr = fopen(argv[1], "w");
-
         /*
-         * FIXME: fopen() should actually detect that we are opening a console
+         * FIXME: fdopen() should actually detect that we are opening a console
          * and it should set line-buffering mode automatically.
          */
         setvbuf(stdout, NULL, _IOLBF, BUFSIZ);
         
-        if ((stdin == NULL)
-            || (stdout == NULL)
-            || (stderr == NULL))
+        if (stdin == NULL)
                 return -2;
+        
+        if (stdout == NULL)
+                return -3;
+        
+        if (stderr == NULL)
+                return -4;
         
         version_print(argv[1]);
         task_id_t id = spawn(argv[2]);
+        
+        task_exit_t texit;
+        int retval;
         task_wait(id, &texit, &retval);