On 2025-03-04 07:58:15+0000, Louis Taylor wrote:

openat is useful to avoid needing to construct relative paths, so expose a wrapper for using it directly.

Signed-off-by: Louis Taylor louis@kragniz.eu

Looks good. I have some tiny nitpicks inline, but if you prefer I can also pick it up as-is.

Acked-by: Thomas Weißschuh linux@weissschuh.net

---

tools/include/nolibc/sys.h | 25 ++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 21 ++++++++++++++++ 2 files changed, 46 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 8f44c33b1213..3cd938f9abda 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -765,6 +765,31 @@ int mount(const char *src, const char *tgt, return __sysret(sys_mount(src, tgt, fst, flags, data)); } +/*

• • int openat(int dirfd, const char *path, int flags[, mode_t mode]);
• */

+static __attribute__((unused)) +int sys_openat(int dirfd, const char *path, int flags, mode_t mode) +{

• return my_syscall4(__NR_openat, dirfd, path, flags, mode);

+}

+static __attribute__((unused)) +int openat(int dirfd, const char *path, int flags, ...) +{

• mode_t mode = 0;
• if (flags & O_CREAT) {

• va_list args;
  

• va_start(args, flags);
  

• mode = va_arg(args, mode_t);
  

• va_end(args);
  

• }
• return __sysret(sys_openat(dirfd, path, flags, mode));

+} /*

• int open(const char *path, int flags[, mode_t mode]);

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 79c3e6a845f3..2a1629938dd6 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1028,6 +1028,26 @@ int test_rlimit(void) return 0; } +static int test_openat(void)

As mentioned in my other mail, this in fact should not be static. Sorry for the back and forth.

+{

• int dev;
• int null;

Can be on a single line.

• dev = openat(AT_FDCWD, "/dev", O_DIRECTORY);
• if (dev < 0)

• return -1;
  

• null = openat(dev, "null", 0);

As per the standard:

The argument flags must include one of the following access modes: O_RDONLY, O_WRONLY, or O_RDWR.

The other tests don't do it either and on Linux it doesn't matter because O_RDONLY == 0. But if we are here anyways.

close(dev) could be moved here for some saved lines.

• if (null < 0) {

• close(dev);
  

• return -1;
  

• }
• close(dev);
• close(null);
• return 0;

+} /* Run syscall tests between IDs <min> and <max>.

• Return 0 on success, non-zero on failure.

@@ -1116,6 +1136,7 @@ int run_syscall(int min, int max) CASE_TEST(mmap_munmap_good); EXPECT_SYSZR(1, test_mmap_munmap()); break; CASE_TEST(open_tty); EXPECT_SYSNE(1, tmp = open("/dev/null", 0), -1); if (tmp != -1) close(tmp); break; CASE_TEST(open_blah); EXPECT_SYSER(1, tmp = open("/proc/self/blah", 0), -1, ENOENT); if (tmp != -1) close(tmp); break;

• CASE_TEST(openat_dir);        EXPECT_SYSNE(1, test_openat(), -1); break;
  

EXPECT_SYSZR() should work here.

CASE_TEST(pipe);              EXPECT_SYSZR(1, test_pipe()); break;
CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
CASE_TEST(poll_stdout);       EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;

-- 2.45.2