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 --- tools/include/nolibc/sys.h | 25 ++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 17 +++++++++++++ 2 files changed, 42 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..e8faddcecf9d 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1028,6 +1028,22 @@ int test_rlimit(void) return 0; }

+int test_openat(void) +{ + int dev, null; + + dev = openat(AT_FDCWD, "/dev", O_DIRECTORY); + if (dev < 0) + return -1; + + null = openat(dev, "null", O_RDONLY); + close(dev); + if (null < 0) + return -1; + + close(null); + return 0; +}

/* Run syscall tests between IDs <min> and <max>. * Return 0 on success, non-zero on failure. @@ -1116,6 +1132,7 @@ 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_SYSZR(1, test_openat()); break; 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;