From 9dcf1391fe8cf7e09c2e9bb66f7f6c094e6268f5 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Fri, 17 Oct 2025 19:57:22 -0400 Subject: kern: filedesc: Implement lseek() function The lseek() function allows the call to resposition the file offset using a specific whence value to govern offsetting semantics Signed-off-by: Ian Moffett --- src/sys/os/os_filedes.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'src/sys/os/os_filedes.c') diff --git a/src/sys/os/os_filedes.c b/src/sys/os/os_filedes.c index ca56fc3..3cbbc6f 100644 --- a/src/sys/os/os_filedes.c +++ b/src/sys/os/os_filedes.c @@ -359,6 +359,44 @@ read(int fd, void *buf, size_t count) return retval; } +off_t +lseek(int fd, off_t offset, int whence) +{ + struct filedesc *fdp; + struct proc *self = proc_self(); + struct vattr attr; + int error; + + if (fd < 0) { + return -EBADF; + } + + fdp = fd_get(self, fd); + if (fdp == NULL) { + return -EBADF; + } + + /* Could not get vnode attributes */ + error = vop_getattr(fdp->vp, &attr); + if (error < 0) { + return 0; + } + + switch (whence) { + case SEEK_SET: + fdp->off = offset; + break; + case SEEK_CUR: + fdp->off += offset; + break; + case SEEK_END: + fdp->off = attr.size; + break; + } + + return fdp->off; +} + /* * ARG0: Path * ARG1: Mode -- cgit v1.2.3