diff options
author | Ian Moffett <ian@osmora.org> | 2025-10-17 20:02:30 -0400 |
---|---|---|
committer | Ian Moffett <ian@osmora.org> | 2025-10-17 20:03:48 -0400 |
commit | 3de9458c5495d67e1c56f44ef8da9850d64087d0 (patch) | |
tree | 2214cd94468ea8a4bc0448ce921b3d56a9149490 /src/lib/libc | |
parent | 0d8e681dcc30774930c373632150b266ce782a14 (diff) |
libc: unistd: Add lseek system call interface
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'src/lib/libc')
-rw-r--r-- | src/lib/libc/include/unistd.h | 10 | ||||
-rw-r--r-- | src/lib/libc/src/unistd/lseek.c | 47 |
2 files changed, 57 insertions, 0 deletions
diff --git a/src/lib/libc/include/unistd.h b/src/lib/libc/include/unistd.h index b668d5b..61b437c 100644 --- a/src/lib/libc/include/unistd.h +++ b/src/lib/libc/include/unistd.h @@ -30,6 +30,7 @@ #ifndef _UNISTD_H #define _UNISTD_H 1 +#include <sys/seek.h> #include <stddef.h> /* Standard stream file numbers */ @@ -74,4 +75,13 @@ ssize_t write(int fd, const void *buf, size_t count); */ ssize_t read(int fd, void *buf, size_t count); +/* + * Reposition the file offset of a file + * + * @fd: File descriptor to reposition + * @offset: Offset to move `fd' to + * @whence: How it should be repositioned + */ +off_t lseek(int fd, off_t offset, int whence); + #endif /* _UNISTD_H */ diff --git a/src/lib/libc/src/unistd/lseek.c b/src/lib/libc/src/unistd/lseek.c new file mode 100644 index 0000000..ade0a1e --- /dev/null +++ b/src/lib/libc/src/unistd/lseek.c @@ -0,0 +1,47 @@ +/* + * Copyright (c) 2025 Ian Marco Moffett and L5 engineers + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the project nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/syscall.h> +#include <unistd.h> +#include <errno.h> + +off_t +lseek(int fd, off_t offset, int whence) +{ + if (fd < 0) { + return -EBADF; + } + + return syscall( + SYS_lseek, + fd, + offset, + whence + ); +} |