[MINI-OS,v3,1/2] 9pfs: add fstat file operation hook

Commit Message

Jürgen Groß March 25, 2025, 9:24 a.m. UTC

Add a file operations fstat hook to the 9pfs frontend.

Signed-off-by: Juergen Gross <[e-mail]>
Reviewed-by: Jason Andryuk <[e-mail]>
Reviewed-by: Samuel Thibault <[e-mail]>
---
V2:
- or file access mode into st_mode (Jason Andryuk)
V3:
- set st_ctime, too (Samuel Thibault)
---
 9pfront.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

Patch

diff --git a/9pfront.c b/9pfront.c
index 1741d600..e676da35 100644
--- a/9pfront.c
+++ b/9pfront.c
@@ -85,6 +85,8 @@  struct file_9pfs {
 
 #define P9_QID_SIZE    13
 
+#define QID_TYPE_DIR   0x80     /* Applies to qid[0]. */
+
 struct p9_header {
     uint32_t size;
     uint8_t cmd;
@@ -950,6 +952,33 @@  static int write_9pfs(struct file *file, const void *buf, size_t nbytes)
     return ret;
 }
 
+static int fstat_9pfs(struct file *file, struct stat *buf)
+{
+    struct file_9pfs *f9pfs = file->filedata;
+    struct p9_stat stat;
+    int ret;
+
+    ret = p9_stat(f9pfs->dev, f9pfs->fid, &stat);
+    if ( ret )
+    {
+        errno = EIO;
+        return -1;
+    }
+
+    buf->st_mode = (stat.qid[0] == QID_TYPE_DIR) ? S_IFDIR : S_IFREG;
+    buf->st_mode |= stat.mode & 0777;
+    buf->st_atime = stat.atime;
+    buf->st_mtime = stat.mtime;
+    buf->st_ctime = stat.mtime;   /* Best available estimate. */
+    buf->st_size = stat.length;
+    buf->st_uid = stat.n_uid;
+    buf->st_gid = stat.n_gid;
+
+    free_stat(&stat);
+
+    return 0;
+}
+
 static int close_9pfs(struct file *file)
 {
     struct file_9pfs *f9pfs = file->filedata;
@@ -1296,6 +1325,7 @@  static const struct file_ops ops_9pfs = {
     .read = read_9pfs,
     .write = write_9pfs,
     .close = close_9pfs,
+    .fstat = fstat_9pfs,
 };
 
 __attribute__((constructor))