selftests/nolibc: disable coredump via setrlimit

qemu-user does has its own implementation of coredumping.
That implementation does not respect the call to
prctl(PR_SET_DUMPABLE, 0) in run_protection().
This leads to a coredump for every test run under qemu-user.

Use also setrlimit() to inhibit coredump creation which is respected by
qemu-user.

Link: https://lore.kernel.org/qemu-devel/20231115-qemu-user-dumpable-v1-2-edbe7f0fbb02@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/20231123-nolibc-rlimit-v1-3-a428b131de2a@weissschuh.net/
Acked-by: Willy Tarreau <w@1wt.eu>

tools/nolibc: add support for getrlimit/setrlimit

The implementation uses the prlimit64 systemcall as that is available on
all architectures.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/20231123-nolibc-rlimit-v1-2-a428b131de2a@weissschuh.net/
Acked-by: Willy Tarreau <w@1wt.eu>

tools/nolibc: drop duplicated testcase ioctl_tiocinq

The same testcase is present on the line above.

Fixes: b4844fa0bdb4 ("selftests/nolibc: implement a few tests for various syscalls")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

selftests/nolibc: make result alignment more robust

Move the check of the existing length into the function so it can't be
forgotten by the caller.

Also hardcode the padding character as only spaces are ever used.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

selftests/nolibc: fix testcase status alignment

Center-align all possible status reports.
Before OK and FAIL were center-aligned in relation to each other but
SKIPPED and FAILED would be left-aligned.

Before:

7 environ_addr = <0x7fffef3e7c50> [OK]
8 environ_envp = <0x7fffef3e7c58> [FAIL]
9 environ_auxv [SKIPPED]
10 environ_total [SKIPPED]
11 environ_HOME = <0x7fffef3e99bd> [OK]
12 auxv_addr [SKIPPED]
13 auxv_AT_UID = 1000 [OK]

After:

7 environ_addr = <0x7ffff13b00a0> [OK]
8 environ_envp = <0x7ffff13b00a8> [FAIL]
9 environ_auxv [SKIPPED]
10 environ_total [SKIPPED]
11 environ_HOME = <0x7ffff13b19bd> [OK]
12 auxv_addr [SKIPPED]
13 auxv_AT_UID = 1000 [OK]

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

selftests/nolibc: add tests for multi-object linkage

While uncommon, nolibc executables can be linked together from multiple
compilation units.
Add some tests to make sure everything works in that case.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/20231012-nolibc-linkage-test-v1-1-315e682768b4@weissschuh.net/
Acked-by: Willy Tarreau <w@1wt.eu>

tools/nolibc: add support for constructors and destructors

With the startup code moved to C, implementing support for
constructors and deconstructors is fairly easy to implement.

Examples for code size impact:

text data bss dec hex filename
21837 104 88 22029 560d nolibc-test.before
22135 120 88 22343 5747 nolibc-test.after
21970 104 88 22162 5692 nolibc-test.after-only-crt.h-changes

The sections are defined by [0].

[0] https://refspecs.linuxfoundation.org/elf/gabi4+/ch5.dynamic.html

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20231007-nolibc-constructors-v2-1-ef84693efbc1@weissschuh.net/

tools/nolibc: drop test for getauxval(AT_PAGESZ)

Other testcases are already testing the same functionality:
* auxv_AT_UID tests getauxval() in general.
* test_getpagesize() tests pagesize() which directly calls
getauxval(AT_PAGESZ).

Link: https://lore.kernel.org/r/20231007-nolibc-auxval-pagesz-v1-1-af00804edead@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

selftests/nolibc: libc-test: avoid -Wstringop-overflow warnings

Newer versions of glibc annotate the poll() function with
__attribute__(access) which triggers a compiler warning inside the
testcase poll_fault.
Avoid this by using a plain NULL which is enough for the testcase.
To avoid potential future warnings also adapt the other EFAULT
testcases, except select_fault as NULL is a valid value for its
argument.

nolibc-test.c: In function ‘run_syscall’:
nolibc-test.c:338:62: warning: ‘poll’ writing 8 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
338 | do { if (!(cond)) result(llen, SKIPPED); else ret += expect_syserr2(expr, expret, experr1, experr2, llen); } while (0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
nolibc-test.c:341:9: note: in expansion of macro ‘EXPECT_SYSER2’
341 | EXPECT_SYSER2(cond, expr, expret, experr, 0)
| ^~~~~~~~~~~~~
nolibc-test.c:905:47: note: in expansion of macro ‘EXPECT_SYSER’
905 | CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
| ^~~~~~~~~~~~
cc1: note: destination object is likely at address zero
In file included from /usr/include/poll.h:1,
from nolibc-test.c:33:
/usr/include/sys/poll.h:54:12: note: in a call to function ‘poll’ declared with attribute ‘access (write_only, 1, 2)’
54 | extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout)
| ^~~~

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

selftests/nolibc: prevent out of bounds access in expect_vfprintf

If read() fails and returns -1 (or returns garbage for some other
reason) buf would be accessed out of bounds.
Only use the return value of read() after it has been validated.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: use correct return type for read() and write()

Avoid truncating values before comparing them.

As printf in nolibc doesn't support ssize_t add casts to int for
printing.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: avoid sign-compare warnings

These warnings will be enabled later so avoid triggering them.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: avoid unused parameter warnings

This warning will be enabled later so avoid triggering it.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: make functions static if possible

This allows the compiler to generate warnings if they go unused.

Functions that are supposed to be used as breakpoints should not be
static, so un-statify those if necessary.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: mark test helpers as potentially unused

When warning about unused functions these would be reported by we want
to keep them for future use.

Suggested-by: Zhangjin Wu <falcon@tinylab.org>
Link: https://lore.kernel.org/lkml/20230731064826.16584-1-falcon@tinylab.org/
Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230731224929.GA18296@1wt.eu/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: drop unused variables

These got copied around as new testcases where created.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: avoid warnings during intptr tests

Recent fix ceb528feb7c8 ("selftests/nolibc: avoid gaps in test numbers")
had the annoying side effect of always returning skipped tests, which
are normally supposed to happen only when certain features are missing
to run the test (missing kernel options, toolchain not supporting
stack-protector etc). As such there are now always warnings. Let's
modify the test to not use the condition and instead use a ternary
expression to check the result.

Fixes: ceb528feb7c8 ("selftests/nolibc: avoid gaps in test numbers")
Cc: Thomas WeiÃ<9F>schuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

tools/nolibc: fix return type of getpagesize()

It's documented as returning int which is also implemented by glibc and
musl, so adopt that return type.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add testcase for pipe

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>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
[wt: fixed the "len" type to size_t to address a sign-compare warning
with upcoming patches]
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: mmap_munmap_good: fix up return value

The other tests use 1 as failure, mmap_munmap_good uses -1 as failure,
let's fix up this.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: avoid buffer underrun in space printing

If the test description is longer than the status alignment the
parameter 'n' to putcharn() would lead to a signed underflow that then
gets converted to a very large unsigned value.
This in turn leads out-of-bound writes in memset() crashing the
application.

The failure case of EXPECT_PTRER() used in "mmap_bad" exhibits this
exact behavior.

Fixes: 29f5540be392 ("selftests/nolibc: add EXPECT_PTREQ, EXPECT_PTRNE and EXPECT_PTRER")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add testcases for startup code

The startup code is critical to get the right argc, argv, envp/environ
and _auxv, let's add a startup test group and the corresponding
testcases.

The "environ" test case is also moved from the stdlib test group to this
new startup test group and it is renamed to "environ_envp".

Since argv0 has been used by many other test cases, let's add testcases
to gurantee it too.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add EXPECT_PTRGE, EXPECT_PTRGT, EXPECT_PTRLE, EXPECT_PTRLT

4 new pointer compare macros are added, they are similar to the integer
compare macros.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: avoid gaps in test numbers

As the test numbers are based on line numbers gaps without testcases are
to be avoided.
Instead use the already existing test condition logic to implement
conditional execution.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: simplify status printing

pad_spc() is only ever used to print the status message of testcases.
The line size is always constant, the return value is never used and the
format string is never used as such.

Remove all the unneeded logic and simplify the API and its users.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: make evaluation of test conditions

If "cond" is a multi-token statement the behavior of the preprocessor
will lead to the negation "!" to be only applied to the first token.
Although currently no test uses such multi-token conditions but it can
happen at any time.

Put braces around "cond" to ensure the negation works as expected.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

tools/nolibc: completely remove optional environ support

In commit 52e423f5b93e ("tools/nolibc: export environ as a weak symbol on i386")
and friends the asm startup logic was extended to directly populate the
"environ" array.

This makes it impossible for "environ" to be dropped by the linker.
Therefore also drop the other logic to handle non-present "environ".

Also add a testcase to validate the initialization of environ.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add chmod_argv0 test

argv0 is readable and chmodable, let's use it for chmod test, but a safe
umask should be used, the readable and executable modes should be
reserved.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: chroot_exe: remove procfs dependency

Since argv0 also works for CONFIG_PROC_FS=n, let's use it instead of
'/proc/self/exe'.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: stat_timestamps: remove procfs dependency

'/proc/self/' is a good path which doesn't have stale time info but it
is only available for CONFIG_PROC_FS=y.

When CONFIG_PROC_FS=n, use argv0 instead of '/proc/self', use '/' for the
worst case.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: chdir_root: restore current path after test

The PWD environment variable has the path of the nolibc-test program,
the current path must be the same as it, otherwise, the test cases will
fail with relative path (e.g. ./nolibc-test).

Since only chdir_root really changes the current path, let's restore it
with the PWD environment variable.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: vfprintf: remove MEMFD_CREATE dependency

The vfprintf test case require to open a temporary file to write, the
old memfd_create() method is perfect but has strong dependency on
MEMFD_CREATE and also TMPFS or HUGETLBFS (see fs/Kconfig):

config MEMFD_CREATE
def_bool TMPFS || HUGETLBFS

And from v6.2, MFD_NOEXEC_SEAL must be passed for the non-executable
memfd, otherwise, The kernel warning will be output to the test result
like this:

Running test 'vfprintf'
0 emptymemfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=1 'init'
"" = "" [OK]

To avoid such warning and also to remove the MEMFD_CREATE dependency,
let's open a file from tmpfs directly.

The /tmp directory is used to detect the existing of tmpfs, if not
there, skip instead of fail.

And further, for pid == 1, the initramfs is loaded as ramfs, which can
be used as tmpfs, so, it is able to further remove TMPFS dependency too.

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/9ad51430-b7c0-47dc-80af-20c86539498d@t-8ch.de
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: prepare /tmp for tests that need to write

create a /tmp directory. If it succeeds, the directory is writable,
which is normally the case when booted from an initramfs anyway.

This will be used instead of procfs for some tests.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Link: https://lore.kernel.org/lkml/20230710050600.9697-1-falcon@tinylab.org/
[wt: removed the unneeded mount() call]
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: fix up failures when CONFIG_PROC_FS=n

For CONFIG_PROC_FS=n, the /proc is not mountable, but the /proc
directory has been created in the prepare() stage whenever /proc is
there or not.

so, the checking of /proc in the run_syscall() stage will be always true
and at last it will fail all of the procfs dependent test cases, which
deviates from the 'cond' check design of the EXPECT_xx macros, without
procfs, these test cases should be skipped instead of failed.

To solve this issue, one method is checking /proc/self instead of /proc,
another method is removing the /proc directory completely for
CONFIG_PROC_FS=n, we apply the second method to avoid misleading the
users.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add a new rmdir() test case

A new rmdir_blah test case is added to remove a non-existing /blah,
which expects failure with ENOENT errno.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: link_cross: use /proc/self/cmdline

For CONFIG_NET=n, there would be no /proc/self/net, so, use
/proc/self/cmdline instead.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: fix up kernel parameters support

kernel parameters allow pass two types of strings, one type is like
'noapic', another type is like 'panic=5', the first type is passed as
arguments of the init program, the second type is passed as environment
variables of the init program.

when users pass kernel parameters like this:

noapic NOLIBC_TEST=syscall

our nolibc-test program will use the test setting from argv[1] and
ignore the one from NOLIBC_TEST environment variable, and at last, it
will print the following line and ignore the whole test setting.

Ignoring unknown test name 'noapic'

reversing the parsing order does solve the above issue:

test = getenv("NOLIBC_TEST");
if (test)
test = argv[1];

but it still doesn't work with such kernel parameters (without
NOLIBC_TEST environment variable):

noapic FOO=bar

To support all of the potential kernel parameters, let's verify the test
setting from both of argv[1] and NOLIBC_TEST environment variable.

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: prefer <sys/reboot.h> to <linux/reboot.h>

Since both glibc and musl provide RB_ flags via <sys/reboot.h>, and we
just add RB_ flags for nolibc, let's use RB_ flags instead of
LINUX_REBOOT_ flags and only reserve the required <sys/reboot.h> header.

This allows compile libc-test for musl libc without the linux headers.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: fix up int_fast16/32_t test cases for musl

musl limits the fast signed int in 32bit, but glibc and nolibc don't, to
let such test cases work on musl, let's provide the type based
SINT_MAX_OF_TYPE(type) and SINT_MIN_OF_TYPE(type).

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/bc635c4f-67fe-4e86-bfdf-bcb4879b928d@t-8ch.de/
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add _LARGEFILE64_SOURCE for musl

_GNU_SOURCE Implies _LARGEFILE64_SOURCE in glibc, but in musl, the
default configuration doesn't enable _LARGEFILE64_SOURCE.

>From include/dirent.h of musl, getdents64 is provided as getdents when
_LARGEFILE64_SOURCE is defined.

#if defined(_LARGEFILE64_SOURCE)
...
#define getdents64 getdents
#endif

Let's define _LARGEFILE64_SOURCE to fix up this compile error:

tools/testing/selftests/nolibc/nolibc-test.c: In function ‘test_getdents64’:
tools/testing/selftests/nolibc/nolibc-test.c:453:8: warning: implicit declaration of function ‘getdents64’; did you mean ‘getdents’? [-Wimplicit-function-declaration]
453 | ret = getdents64(fd, (void *)buffer, sizeof(buffer));
| ^~~~~~~~~~
| getdents
/usr/bin/ld: /tmp/ccKILm5u.o: in function `test_getdents64':
nolibc-test.c:(.text+0xe3e): undefined reference to `getdents64'
collect2: error: ld returned 1 exit status

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: gettid: restore for glibc and musl

As the gettid manpage [1] shows, glibc 2.30 has gettid support, so,
let's enable the test for glibc >= 2.30.

gettid works on musl too.

[1]: https://man7.org/linux/man-pages/man2/gettid.2.html

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: stat_fault: silence NULL argument warning with glibc

Use another invalid address (void *)1 instead of NULL to silence this
compile warning with glibc:

$ make libc-test
CC libc-test
nolibc-test.c: In function ‘run_syscall’:
nolibc-test.c:622:49: warning: null argument where non-null required (argument 1) [-Wnonnull]
622 | CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
| ^~~~
nolibc-test.c:304:79: note: in definition of macro ‘EXPECT_SYSER2’
304 | do { if (!cond) pad_spc(llen, 64, "[SKIPPED]\n"); else ret += expect_syserr2(expr, expret, experr1, experr2, llen); } while (0)
| ^~~~
nolibc-test.c:622:33: note: in expansion of macro ‘EXPECT_SYSER’
622 | CASE_TEST(stat_fault); EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add mmap_munmap_good test case

mmap() a file with a good offset and then munmap() it. a non-zero offset
is passed to test the 6th argument of my_syscall6().

Note, it is not easy to find a unique file for mmap() in different
scenes, so, a file list is used to search the right one:

- /dev/zero: is commonly used to allocate anonymous memory and is likely
present and readable

- /proc/1/exe: for 'run' and 'run-user' target, 'run-user' can not find
'/proc/self/exe'

- /proc/self/exe: for 'libc-test' target, normal program 'libc-test' has
no permission to access '/proc/1/exe'

- argv0: the path of the program itself, let it pass even with worst
case scene: no procfs and no /dev/zero

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230702193306.GK16233@1wt.eu/
Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/bff82ea6-610b-4471-a28b-6c76c28604a6@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add munmap_bad test case

The addr argument of munmap() must be a multiple of the page size,
passing invalid (void *)1 addr expects failure with -EINVAL.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add mmap_bad test case

The length argument of mmap() must be greater than 0, passing a zero
length argument expects failure with -EINVAL.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add sbrk_0 to test current brk getting

>From musl 0.9.14 (to the latest version 1.2.3), both sbrk() and brk()
have almost been disabled for they conflict with malloc, only sbrk(0) is
still permitted as a way to get the current location of the program
break, let's support such case.

EXPECT_PTRNE() is used to expect sbrk() always successfully getting the
current break.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: add EXPECT_PTREQ, EXPECT_PTRNE and EXPECT_PTRER

The syscalls like sbrk() and mmap() return pointers, to test them, more
pointer compare test macros are required, add them:

- EXPECT_PTREQ() expects two equal pointers.
- EXPECT_PTRNE() expects two non-equal pointers.
- EXPECT_PTRER() expects failure with a specified errno.
- EXPECT_PTRER2() expects failure with one of two specified errnos.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: prepare: create /dev/zero

/dev/zero is commonly used to allocate anonymous memory, it is a very
good file for tests, let's prepare it.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230702193306.GK16233@1wt.eu/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: export argv0 for some tests

argv0 is the path to nolibc-test program itself, which is a very good
always existing readable file for some tests, let's export it.

Note, the path may be absolute or relative, please make sure the tests
work with both of them. If it is relative, we must make sure the current
path is the one specified by the PWD environment variable.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/ZKKbS3cwKcHgnGwu@1wt.eu/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: simplify call to ioperm

Since commit 53fcfafa8c5c ("tools/nolibc/unistd: add syscall()") nolibc
has support for syscall(2).
Use it to get rid of some ifdef-ery.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

selftests/nolibc: drop test chmod_net

The test relies on /proc/$PID/net to allow chmod() operations.
It is the only file or directory in /proc/$PID/ to allow this and a bug.
That bug will be fixed in the next patch in the series and therefore
the test would start failing.

Link: https://lore.kernel.org/lkml/d0d111ef-edae-4760-83fb-36db84278da1@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Fixes: b4844fa0bdb4 ("selftests/nolibc: implement a few tests for various syscalls")
Tested-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Message-Id: <20230624-proc-net-setattr-v1-1-73176812adee@weissschuh.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>

selftests/nolibc: add new gettimeofday test cases

These 2 test cases are added to cover the normal using scenes of
gettimeofday().

They have been used to trigger and fix up such issue with nolibc:

nolibc-test.c:(.text.gettimeofday+0x54): undefined reference to `__aeabi_ldivmod'

This issue happens while there is no "unsigned int" conversion in the
coming new clock_gettime / clock_gettime64 syscall path of
gettimeofday():

tv->tv_usec = ts.tv_nsec / 1000;

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/linux-riscv/280867a8-7601-4a96-9b85-87668e1f1282@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: remove gettimeofday_bad1/2 completely

In the clock_gettime / clock_gettime64 syscalls based gettimeofday(),
there is no way to let kernel space 'fixup' the invalid data pointer of
'struct timeval' and 'struct timezone' for us for we need to read
timespec from kernel space and then convert to timeval in user-space
ourselves and also we need to simply ignore and reset timezone in
user-space.

Without this removal, the invalid (void *)1 address will trigger a
sigsegv (signum = 11) signal and stop the whole test.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/linux-riscv/20230528113325.GJ1956@1wt.eu/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: support two errnos with EXPECT_SYSER2()

Some functions may be implemented with different syscalls in different
platforms, these syscalls may set different errnos for the same
arguments, let's support such cases.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/linux-riscv/20230528113325.GJ1956@1wt.eu/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: use INT_MAX instead of __INT_MAX__

nolibc now has INT_MAX in stdint.h, so, don't mix INT_MAX and
__INT_MAX__, unify them to INT_MAX.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: not include limits.h for nolibc

When compile nolibc-test.c with 2.31 glibc, we got such error:

In file included from /usr/riscv64-linux-gnu/include/sys/cdefs.h:452,
from /usr/riscv64-linux-gnu/include/features.h:461,
from /usr/riscv64-linux-gnu/include/bits/libc-header-start.h:33,
from /usr/riscv64-linux-gnu/include/limits.h:26,
from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:194,
from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/syslimits.h:7,
from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:34,
from /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/nolibc-test.c:6:
/usr/riscv64-linux-gnu/include/bits/wordsize.h:28:3: error: #error "rv32i-based targets are not supported"
28 | # error "rv32i-based targets are not supported"

Glibc (>= 2.33) commit 5b6113d62efa ("RISC-V: Support the 32-bit ABI
implementation") fixed up above error.

As suggested by Thomas, defining INT_MIN/INT_MAX for nolibc can remove
the including of limits.h, and therefore no above error. of course, the
other libcs still require limits.h, move it to the right place.

The LONG_MIN/LONG_MAX are also defined too.

Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/linux-riscv/09d60dc2-e298-4c22-8e2f-8375861bd9be@t-8ch.de/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: fix up compile warning with glibc on x86_64

Compiling nolibc-test.c with gcc on x86_64 got such warning:

tools/testing/selftests/nolibc/nolibc-test.c: In function ‘expect_eq’:
tools/testing/selftests/nolibc/nolibc-test.c:177:24: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘uint64_t’ {aka ‘long unsigned int’} [-Wformat=]
177 | llen += printf(" = %lld ", expr);
| ~~~^ ~~~~
| | |
| | uint64_t {aka long unsigned int}
| long long int
| %ld

It because that glibc defines uint64_t as "unsigned long int" when word
size (means sizeof(long)) is 64bit (see include/bits/types.h), but
nolibc directly use the 64bit "unsigned long long" (see
tools/include/nolibc/stdint.h), which is simpler, seems kernel uses it
too (include/uapi/asm-generic/int-ll64.h).

use a simple conversion to solve it.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/linux-riscv/20230529130449.GA2813@1wt.eu/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: remove test gettimeofday_null

gettimeofday() is not guaranteed by posix to handle a NULL value as first
argument gracefully.
On glibc for example it crashes. (When not going through the vdso)

Link: https://lore.kernel.org/lkml/96f1134d-ce6e-4d82-ae00-1cd4038809c4@t-8ch.de/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: ensure fast64 integer types have 64 bits

On 32bit platforms size_t is not enough to represent [u]int_fast64_t.

Fixes: 3e9fd4e9a1d5 ("tools/nolibc: add integer types and integer limit macros")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: test_fork: fix up duplicated print

running nolibc-test with glibc on x86_64 got such print issue:

29 execve_root = -1 EACCES [OK]
30 fork30 fork = 0 [OK]
31 getdents64_root = 712 [OK]

The fork test case has three printf calls:

(1) llen += printf("%d %s", test, #name);
(2) llen += printf(" = %d %s ", expr, errorname(errno));
(3) llen += pad_spc(llen, 64, "[FAIL]\n"); --> vfprintf()

In the following scene, the above issue happens:

(a) The parent calls (1)
(b) The parent calls fork()
(c) The child runs and shares the print buffer of (1)
(d) The child exits, flushs the print buffer and closes its own stdout/stderr
* "30 fork" is printed at the first time.
(e) The parent calls (2) and (3), with "\n" in (3), it flushs the whole buffer
* "30 fork = 0 ..." is printed

Therefore, there are two "30 fork" in the stdout.

Between (a) and (b), if flush the stdout (and the sterr), the child in
stage (c) will not be able to 'see' the print buffer.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: remove the duplicated gettimeofday_bad2

There were two exactly similar occurrences of this test.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: print name instead of number for EOVERFLOW

EOVERFLOW will be used in the coming time64 syscalls support.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: support nanoseconds in stat()

Keep backwards compatibility through unions.

The compatibility macros like

#define st_atime st_atim.tv_sec

as documented in stat(3type) don't work for nolibc because it would
break with other stat-like structures that contain the field st_atime.

The stx_atime, stx_mtime, stx_ctime are in type of 'struct
statx_timestamp', which is incompatible with 'struct timespec', should
be converted explicitly.

/* include/uapi/linux/stat.h */

struct statx_timestamp {
__s64 tv_sec;
__u32 tv_nsec;
__s32 __reserved;
};

/* include/uapi/linux/time.h */
struct timespec {
__kernel_old_time_t tv_sec; /* seconds */
long tv_nsec; /* nanoseconds */
};

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/linux-riscv/3a3edd48-1ace-4c89-89e8-9c594dd1b3c9@t-8ch.de/
Co-authored-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
[wt: squashed Zhangjin & Thomas' patches into one to preserve "bisectability"]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: prevent coredumps during test execution

The child process forked during stackprotector tests intentionally gets
killed with SIGABRT. By default this will trigger writing a coredump.
The writing of the coredump can spam the systems coredump machinery and
take some time.

Timings for the full run of nolibc-test:
Before: 200ms
After: 20ms

This is on a desktop x86 system with systemd-coredumpd enabled.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add support for prctl()

It will be used to disable core dumps from the child spawned to validate
the stack protector functionality.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add autodetection for stackprotector support

The stackprotector support in nolibc should be enabled iff it is also
enabled in the compiler.
Use the preprocessor defines added by gcc and clang if stackprotector
support is enable to automatically do so in nolibc.

This completely removes the need for any user-visible API.

To avoid inlining the lengthy preprocessor check into every user
introduce a new header compiler.h that abstracts the logic away.

As the define NOLIBC_STACKPROTECTOR is now not user-relevant anymore
prefix it with an underscore.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230520133237.GA27501@1wt.eu/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add test for __stack_chk_guard initialization

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: reduce syscalls during space padding

Previously each space character used for alignment during test execution
was written in a single write() call.
This would make the output from strace fairly unreadable.
Coalesce all spaces into a single call to write().

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: syscall_args: use generic __NR_statx

Compiling nolibc-test.c for rv32 got such error:

tools/testing/selftests/nolibc/nolibc-test.c:599:57: error: ‘__NR_fstat’ undeclared (first use in this function)
599 | CASE_TEST(syscall_args); EXPECT_SYSER(1, syscall(__NR_fstat, 0, NULL), -1, EFAULT); break;

The generic include/uapi/asm-generic/unistd.h used by rv32 doesn't
support __NR_fstat, use the more generic __NR_statx instead:

Running test 'syscall'
69 syscall_noargs = 1 [OK]
70 syscall_args = -1 EFAULT [OK]

__NR_statx has been added from v4.10:

commit a528d35e8bfc ("statx: Add a system call to make enhanced file info available")

It has been supported by all of the platforms since at least from v4.20.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/linux-riscv/ee8b1f02-ded1-488b-a3a5-68774f0349b5@app.fastmail.com/
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc/unistd: add syscall()

syscall() is used by "normal" libcs to allow users to directly call
syscalls.
By having the same syntax inside nolibc users can more easily write code
that works with different libcs.

The macro logic is adapted from systemtaps STAP_PROBEV() macro that is
released in the public domain / CC0.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add testcase for fork()/waitpid()

On s390 the arguments to clone() which is used by fork() are different
than other archs.
Make sure everything works correctly.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: use C89 comment syntax

Most of nolibc is already using C89 comments.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: use standard __asm__ statements

Most of the code was migrated to C99-conformant __asm__ statements
before. It seems string.h was missed.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add testcases for vfprintf

vfprintf() is complex and so far did not have proper tests.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: fix build of the test case using glibc

Some extra tests for various integer types and limits were added by
commit d1209597ff00 ("tools/nolibc: add tests for the integer limits
in stdint.h"), but we forgot to retest with glibc. Stddef and stdint
are now needed for the program to build there.

Cc: Vincent Dagonneau <v@vda.io>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: tests: fix build on non-c99 compliant compilers

Commit 9735716830f2 ("tools/nolibc: tests: add test for -fstack-protector")
brought a declaration inside the initialization statement of a for loop,
which breaks the build on compilers that do not default to c99
compatibility, making it more difficult to validate that the lib still
builds on such compilers. The fix is trivial, so let's move the
declaration to the variables block of the function instead. No backport
is needed.

Cc: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: tests: use volatile to force stack smashing

Use a volatile pointer to write outside the buffer so the compiler can't
optimize it away.

Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/lkml/c0584807-511c-4496-b062-1263ea38f349@p183/
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: tests: add test for -fstack-protector

Test the previously introduce stack protector functionality in nolibc.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: tests: constify test_names

Nothing ever modifies this structure.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: skip the chroot_root and link_dir tests when not privileged

These two tests always fail when the program is started natively as an
unprivileged user, and require the user to carefully check the output
of "make run-user" and ignore them.

Let's add an euid check and condition these two tests to euid==0. Now
the test case stops needlessly reporting failures. E.g.:

$ make -C tools/testing/selftests/nolibc run-user
...
CC nolibc-test
123 test(s) passed.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: add tests for the integer limits in stdint.h

This commit adds tests for the limits added in a previous commit. The
limits are defined in decimal in stdint.h and as hexadecimal in the
tests (e.g. 0x7f = 127 or 0x80 = -128). Hopefully it catches some of the
most egregious mistakes.

As we rely on the compiler to provide __SIZEOF_LONG__, we also test
whether it is defined.

Signed-off-by: Vincent Dagonneau <v@vda.io>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/nolibc: enlarge column width of tests

This commit enlarges the column width from 40 to 64 characters to make
room for longer tests

Signed-off-by: Vincent Dagonneau <v@vda.io>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: Add `getpagesize(2)` selftest

Test the getpagesize() function. Make sure it returns the correct
value.

Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: Add 7 tests for memcmp()

This adds 7 combinations of input values for memcmp() using signed and
unsigned bytes, which will trigger on the original code before Rasmus'
fix. This is mostly aimed at helping backporters verify their work, and
showing how tests for corner cases can be added to the selftests suite.

Before the fix it reports:
12 memcmp_20_20 = 0 [OK]
13 memcmp_20_60 = -64 [OK]
14 memcmp_60_20 = 64 [OK]
15 memcmp_20_e0 = 64 [FAIL]
16 memcmp_e0_20 = -64 [FAIL]
17 memcmp_80_e0 = -96 [OK]
18 memcmp_e0_80 = 96 [OK]

And after:
12 memcmp_20_20 = 0 [OK]
13 memcmp_20_60 = -64 [OK]
14 memcmp_60_20 = 64 [OK]
15 memcmp_20_e0 = -192 [OK]
16 memcmp_e0_20 = 192 [OK]
17 memcmp_80_e0 = -96 [OK]
18 memcmp_e0_80 = 96 [OK]

Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: support glibc as well

Adding support for glibc can be useful to distinguish between bugs in
nolibc and bugs in the kernel when a syscall reports an unusual value.

It's not that much work and should not affect the long term
maintainability of the tests. The necessary changes can essentially be
summed up like this:
- set _GNU_SOURCE a the top to access some definitions
- many includes added when we know we don't come from nolibc (missing
the stdio include guard)
- disable gettid() which is not exposed by glibc
- disable gettimeofday's support of bad pointers since these crash
in glibc
- add a simple itoa() for errorname(); strerror() is too verbose (no
way to get short messages). strerrorname_np() was added in modern
glibc (2.32) to do exactly this but that 's too recent to be usable
as the default fallback.
- use the standard ioperm() definition. May be we need to implement
ioperm() in nolibc if that's useful.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: condition some tests on /proc existence

If /proc is not available (program run inside a chroot or without
sufficient permissions), it's better to disable the associated tests.
Some will be preserved like the ones which check for a failure to
create some entries there since they're still supposed to fail.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: recreate and populate /dev and /proc if missing

Most of the time the program will be run alone in an initramfs. There
is no value in requiring the user to populate /dev and /proc for such
tests, we can do it ourselves, and it participates to the tests at the
same time.

What's done here is that when called as init (getpid()==1) we check
if /dev exists or create it, if /dev/console and /dev/null exists,
otherwise we try to mount a devtmpfs there, and if it fails we fall
back to mknod. The console is reopened if stdout was closed. Finally
/proc is created and mounted if /proc/self cannot be found. This is
sufficient for most tests.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: on x86, support exiting with isa-debug-exit

QEMU, when started with "-device isa-debug-exit -no-reboot" will exit
with status code 2N+1 when N is written to 0x501. This is particularly
convenient for automated tests but this is not portable. As such we
only enable this on x86_64 when pid==1. In addition, this requires an
ioperm() call but in order not to have to define arch-specific syscalls
we just perform the syscall by hand there.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: exit with poweroff on success when getpid() == 1

The idea is to ease automated testing under qemu. If the test succeeds
while running as PID 1, indicating the system was booted with init=/test,
let's just power off so that qemu can exit with a successful code. In
other situations it will exit and provoke a panic, which may be caught
for example with CONFIG_PVPANIC.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: add a few tests for some libc functions

The test series called "stdlib" covers some libc functions (string,
stdlib etc). By default they are automatically run after "syscall"
but may be requested in argument or in variable NOLIBC_TEST.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: implement a few tests for various syscalls

This adds 63 tests covering about 34 syscalls. Both successes and
failures are tested. Two tests fail when run as unprivileged user
(link_dir which returns EACCESS instead of EPERM, and chroot which
returns EPERM). One test (execve("/")) expects to fail on EACCESS,
but needs to have valid arguments otherwise the kernel will log a
message. And a few tests require /proc to be mounted.

The code is not pretty since all tests are one-liners, sometimes
resulting in long lines, especially when using compount statements to
preset a line, but it's convenient and doesn't obfuscate the code,
which is important to understand what failed.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: support a test definition format

It now becomes possible to pass a string either in argv[1] or in the
NOLIBC_TEST environment variable (the former having precedence), to
specify which tests to run. The format is:

testname[:range]*[,testname...]

Where a range is either a single value or the min and max numbers of the
test IDs in a sequence, delimited by a dash. Multiple ranges are possible.
This should provide enough flexibility to focus on certain failing parts
just by playing with the boot command line in a boot loader or in qemu
depending on what is accessible.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

selftests/nolibc: add basic infrastructure to ease creation of nolibc tests

This creates a "nolibc" selftest that intends to test various parts of
the nolibc component, both in terms of build and execution for a given
architecture.

The aim is for it to be as simple to run as a kernel build, by just
passing the compiler (for the build) and the ARCH (for kernel and
execution).

It brings a basic squeleton made of a single C file that will ease testing
and error reporting. The code will be arranged so that it remains easy to
add basic tests for syscalls or library calls that may rely on a condition
to be executed, and whose result is compared to a value or to an error
with a specific errno value.

Tests will just use a relative line number in switch/case statements as
an index, saving the user from having to maintain arrays and complicated
functions which can often just be one-liners.

MAINTAINERS was updated.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>