# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1627247919 -7200
# Node ID 5be26f9f495e53972bae93ff14584c0738c7b727
# Parent  88af0701edffe6d8e76b625a5a443d3ff9a81b7f
Introduced file creation support to the ext2 file opener, switching the file
facilities test to use the ext2 opener and filesystem.

diff -r 88af0701edff -r 5be26f9f495e conf/dstest_file.cfg
--- a/conf/dstest_file.cfg	Sun Jul 25 17:14:53 2021 +0200
+++ b/conf/dstest_file.cfg	Sun Jul 25 23:18:39 2021 +0200
@@ -4,20 +4,32 @@
 
 local l = L4.default_loader;
 
-local server = l:new_channel();
+local blocksvr = l:new_channel();
+
+l:startv({
+    caps = {
+      server = blocksvr:svr(),
+    },
+    log = { "blocksvr", "r" },
+  },
+  "rom/dstest_block_server", "10");
+
+local ext2svr = l:new_channel();
 
 l:startv({
     caps = {
-      server = server:svr(),
+      blocksvr = blocksvr,
+      ext2svr = ext2svr:svr(),
     },
-    log = { "server", "r" },
+    log = { "ext2svr", "y" },
   },
-  "rom/dstest_block_server", "10");
+  "rom/dstest_ext2_server", "blocksvr", "rom/e2test.fs", "10", "ext2svr");
 
 l:startv({
     caps = {
-      server = server,
+      server = ext2svr,
     },
     log = { "client", "g" },
   },
-  "rom/dstest_file_client", "new file");
+  -- program, file to create, user identifier
+  "rom/dstest_file_client", "home/paulb/new file", "1000");
diff -r 88af0701edff -r 5be26f9f495e conf/dstest_file.list
--- a/conf/dstest_file.list	Sun Jul 25 17:14:53 2021 +0200
+++ b/conf/dstest_file.list	Sun Jul 25 23:18:39 2021 +0200
@@ -1,9 +1,11 @@
 entry dstest_file
 roottask moe rom/dstest_file.cfg
 module dstest_file.cfg
+module e2test.fs
 module l4re
 module ned
 module dstest_file_client
+module dstest_ext2_server
 module dstest_block_server
 module lib4re-c.so
 module lib4re-c-util.so
diff -r 88af0701edff -r 5be26f9f495e libfsserver/lib/files/ext2_file_opener.cc
--- a/libfsserver/lib/files/ext2_file_opener.cc	Sun Jul 25 17:14:53 2021 +0200
+++ b/libfsserver/lib/files/ext2_file_opener.cc	Sun Jul 25 23:18:39 2021 +0200
@@ -19,7 +19,11 @@
  * Boston, MA  02110-1301, USA
  */
 
+#include <e2access/access.h>
 #include <e2access/image.h>
+#include <e2access/path.h>
+
+#include <systypes/fcntl.h>
 
 #include "ext2_file_accessor.h"
 #include "ext2_file_opener.h"
@@ -28,15 +32,52 @@
 
 long Ext2FileOpener::get_fileid(const char *path, flags_t flags, fileid_t *fileid)
 {
+    const char *filename = path;
+
     /* Obtain the inode number. */
 
     ext2_ino_t ino;
-    errcode_t retval = image_find_path(_fs, &path, &ino);
+    errcode_t retval = image_find_path(_fs, &filename, &ino);
 
-    // NOTE: Support file creation.
+    /* Handle a missing file. */
 
     if (retval)
+    {
+        /* Create a missing file if possible. */
+
+        if (flags & O_CREAT)
+        {
+            /* Determine whether only the leafname is left of the path, with
+               the inode number referring to the parent directory. */
+
+            if (path_is_leafname(filename))
+            {
+                struct ext2_inode inode_parent;
+
+                /* Determine write access in the directory. */
+
+                retval = ext2fs_read_inode(_fs, ino, &inode_parent);
+
+                if (retval)
+                    return -L4_EIO;
+
+                if (!access_can_write(_user, &inode_parent))
+                    return -L4_EPERM;
+
+                /* If so, use the parent directory inode to create a new file. */
+
+                if (image_create_file(_fs, ino, filename, 0666 & ~_user.umask,
+                                      _user.uid, _user.gid, &ino))
+                    return -L4_EIO;
+
+                *fileid = (fileid_t) ino;
+                return L4_EOK;
+            }
+        }
+
+        *fileid = FILEID_INVALID;
         return -L4_ENOENT;
+    }
 
     *fileid = (fileid_t) ino;
     return L4_EOK;
diff -r 88af0701edff -r 5be26f9f495e tests/dstest_file_client.cc
--- a/tests/dstest_file_client.cc	Sun Jul 25 17:14:53 2021 +0200
+++ b/tests/dstest_file_client.cc	Sun Jul 25 23:18:39 2021 +0200
@@ -137,16 +137,36 @@
 {
   if (argc < 2)
   {
-    printf("Need a filename.\n");
+    printf("Need a filename and an optional user identifier (if used with a filesystem).\n");
     return 1;
   }
 
   char *filename = argv[1];
+  sys_uid_t uid = argc > 2 ? atoi(argv[2]) : 0;
+  file_t *file1, *file2;
 
-  /* Invoke the open function to receive each file reference. */
+  /* With a user, open a user-specific file opener. */
+
+  if (uid)
+  {
+    l4_cap_idx_t opener = client_open_for_user(uid, uid, 0022);
 
-  file_t *file1 = client_open(filename, O_RDWR | O_CREAT);
-  file_t *file2 = client_open(filename, O_RDWR);
+    if (l4_is_invalid_cap(opener))
+    {
+      printf("Could not obtain opener for file.\n");
+      return 1;
+    }
+
+    /* Invoke the open method to receive the file reference. */
+
+    file1 = client_open_using(filename, O_RDWR | O_CREAT, opener);
+    file2 = client_open_using(filename, O_RDWR, opener);
+  }
+  else
+  {
+    file1 = client_open(filename, O_RDWR | O_CREAT);
+    file2 = client_open(filename, O_RDWR);
+  }
 
   if ((file1 == NULL) || (file2 == NULL))
   {