[incubator-nuttx] branch master updated: xtensa hostfs: Make host_stat populate st_size

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new 16d3e78  xtensa hostfs: Make host_stat populate st_size
16d3e78 is described below

commit 16d3e787de940041277bfffa85acad0126afb877
Author: YAMAMOTO Takashi <ya...@midokura.com>
AuthorDate: Wed Mar 10 11:17:33 2021 +0900

    xtensa hostfs: Make host_stat populate st_size
    
    A clumsy implementation using lseek.
    This would allow more applications to use hostfs directly.
    
    Tested lightly with CONFIG_EXAMPLES_STAT.
---
 arch/xtensa/src/common/xtensa_hostfs.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/xtensa/src/common/xtensa_hostfs.c b/arch/xtensa/src/common/xtensa_hostfs.c
index 094a657..d63682d 100644
--- a/arch/xtensa/src/common/xtensa_hostfs.c
+++ b/arch/xtensa/src/common/xtensa_hostfs.c
@@ -135,10 +135,21 @@ int host_dup(int fd)
 
 int host_fstat(int fd, struct stat *buf)
 {
-  /* XXX determine the size using lseek? */
+  /* Determine the size using lseek.
+   *
+   * Assumptions:
+   *  - host_lseek never fails
+   *  - It's ok to change the file offset temporarily as
+   *    hostfs_semtake provides enough serialization.
+   */
+
+  off_t saved_off = host_lseek(fd, 0, SEEK_CUR);
+  off_t size = host_lseek(fd, 0, SEEK_END);
+  host_lseek(fd, saved_off, SEEK_SET);
 
   memset(buf, 0, sizeof(*buf));
   buf->st_mode = S_IFREG | 0777;
+  buf->st_size = size;
   return 0;
 }