Hi Willy and Thomas,
In v3, I have fixed all the problems you mentioned.
Welcome any other suggestion.
--- Changes in v3: - Fix the missing return - Fix __NR_pipe to __NR_pipe2 - Fix the missing static - Test case works in one process - Link to v2: https://lore.kernel.org/all/cover.1690733545.git.tanyuan@tinylab.org
Changes in v2: - Use sys_pipe2 to implement the pipe() - Use memcmp() instead of strcmp() - Link to v1: https://lore.kernel.org/all/cover.1690307717.git.tanyuan@tinylab.org
--- Yuan Tan (2): tools/nolibc: add pipe() and pipe2() support selftests/nolibc: add testcase for pipe
tools/include/nolibc/sys.h | 24 ++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 22 ++++++++++++++++++ 2 files changed, 46 insertions(+)
According to manual page [1], posix spec [2] and source code like arch/mips/kernel/syscall.c, for historic reasons, the sys_pipe() syscall on some architectures has an unusual calling convention. It returns results in two registers which means there is no need for it to do verify the validity of a userspace pointer argument. Historically that used to be expensive in Linux. These days the performance advantage is negligible.
Nolibc doesn't support the unusual calling convention above, luckily Linux provides a generic sys_pipe2() with an additional flags argument from 2.6.27. If flags is 0, then pipe2() is the same as pipe(). So here we use sys_pipe2() to implement the pipe().
pipe2() is also provided to allow users to use flags argument on demand.
[1]: https://man7.org/linux/man-pages/man2/pipe.2.html [2]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/pipe.html
Suggested-by: Zhangjin Wu falcon@tinylab.org Link: https://lore.kernel.org/all/20230729100401.GA4577@1wt.eu/ Signed-off-by: Yuan Tan tanyuan@tinylab.org --- tools/include/nolibc/sys.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 8bfe7db20b80..56f63eb48a1b 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -752,6 +752,30 @@ int open(const char *path, int flags, ...) }
+/* + * int pipe2(int pipefd[2], int flags); + * int pipe(int pipefd[2]); + */ + +static __attribute__((unused)) +int sys_pipe2(int pipefd[2], int flags) +{ + return my_syscall2(__NR_pipe2, pipefd, flags); +} + +static __attribute__((unused)) +int pipe2(int pipefd[2], int flags) +{ + return __sysret(sys_pipe2(pipefd, flags)); +} + +static __attribute__((unused)) +int pipe(int pipefd[2]) +{ + return pipe2(pipefd, 0); +} + + /* * int prctl(int option, unsigned long arg2, unsigned long arg3, * unsigned long arg4, unsigned long arg5);
Add a test case of pipe that sends and receives message in a single process.
Suggested-by: Thomas Weißschuh thomas@t-8ch.de Suggested-by: Willy Tarreau w@1wt.eu Link: https://lore.kernel.org/all/c5de2d13-3752-4e1b-90d9-f58cca99c702@t-8ch.de/ Signed-off-by: Yuan Tan tanyuan@tinylab.org --- tools/testing/selftests/nolibc/nolibc-test.c | 22 ++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 03b1d30f5507..e5667fa3cf0a 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -767,6 +767,27 @@ int test_mmap_munmap(void) return ret; }
+static int test_pipe(void) +{ + const char *const msg = "hello, nolibc"; + int pipefd[2]; + char buf[32]; + ssize_t len; + + if (pipe(pipefd) == -1) + return 1; + + write(pipefd[1], msg, strlen(msg)); + close(pipefd[1]); + len = read(pipefd[0], buf, sizeof(buf)); + close(pipefd[0]); + + if (len != strlen(msg)) + return 1; + + return !!memcmp(buf, msg, len); +} +
/* Run syscall tests between IDs <min> and <max>. * Return 0 on success, non-zero on failure. @@ -851,6 +872,7 @@ 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(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; CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
Aug 1, 2023 17:40:01 Yuan Tan tanyuan@tinylab.org:
Hi Willy and Thomas,
In v3, I have fixed all the problems you mentioned.
Welcome any other suggestion.
Changes in v3:
- Fix the missing return
- Fix __NR_pipe to __NR_pipe2
- Fix the missing static
- Test case works in one process
- Link to v2:
https://lore.kernel.org/all/cover.1690733545.git.tanyuan@tinylab.org
Changes in v2:
- Use sys_pipe2 to implement the pipe()
- Use memcmp() instead of strcmp()
- Link to v1:
https://lore.kernel.org/all/cover.1690307717.git.tanyuan@tinylab.org
Yuan Tan (2): tools/nolibc: add pipe() and pipe2() support selftests/nolibc: add testcase for pipe
tools/include/nolibc/sys.h | 24 ++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 22 ++++++++++++++++++ 2 files changed, 46 insertions(+)
For the full series:
Reviewed-by: Thomas Weißschuh linux@weissschuh.net
Thanks!
Hi,
On Tue, Aug 01, 2023 at 05:42:57PM +0200, Thomas Weißschuh wrote:
Aug 1, 2023 17:40:01 Yuan Tan tanyuan@tinylab.org:
Hi Willy and Thomas,
In v3, I have fixed all the problems you mentioned.
Welcome any other suggestion.
Changes in v3:
- Fix the missing return
- Fix __NR_pipe to __NR_pipe2
- Fix the missing static
- Test case works in one process
- Link to v2:
https://lore.kernel.org/all/cover.1690733545.git.tanyuan@tinylab.org
Changes in v2:
- Use sys_pipe2 to implement the pipe()
- Use memcmp() instead of strcmp()
- Link to v1:
https://lore.kernel.org/all/cover.1690307717.git.tanyuan@tinylab.org
Yuan Tan (2): tools/nolibc: add pipe() and pipe2() support selftests/nolibc: add testcase for pipe
tools/include/nolibc/sys.h | 24 ++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 22 ++++++++++++++++++ 2 files changed, 46 insertions(+)
For the full series:
Reviewed-by: Thomas Weißschuh linux@weissschuh.net
Thank you both, now queued on top of the rest in 20230801-nolibc-next-1. Thomas I'll try to review your last series tomorrow, at first glance it looks OK.
Thanks, Willy
linux-kselftest-mirror@lists.linaro.org
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Thomas Weißschuh -
Willy Tarreau -
Yuan Tan