tools/nolibc: add limits.h shim header

limits.h is a widely used standard header. Missing it from nolibc requires
adoption effort to port applications.

Add a shim header which includes the global

tools/nolibc: add limits.h shim header

limits.h is a widely used standard header. Missing it from nolibc requires
adoption effort to port applications.

Add a shim header which includes the global nolibc.h header.
It makes all nolibc symbols available.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Willy Tarreau <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Acked-by: Willy Tarreau <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

show more ...

tools/nolibc: add support for directory access

Add an implementation for directory access operations.
To keep nolibc itself allocation-free, a "DIR *" does not point to any
data, but directly encode

tools/nolibc: add support for directory access

Add an implementation for directory access operations.
To keep nolibc itself allocation-free, a "DIR *" does not point to any
data, but directly encodes a filedescriptor number, equivalent to "FILE *".
Without any per-directory storage it is not possible to implement
readdir() POSIX confirming. Instead only readdir_r() is provided.
While readdir_r() is deprecated in glibc, the reasons for that are
not applicable to nolibc.

Signed-off-by: Thomas Weißschuh <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Thomas Weißschuh <[email protected]>

show more ...

tools/nolibc: add stdbool.h header

stdbool.h is very simple.
Provide an implementation for the user convenience.

Acked-by: Willy Tarreau <[email protected]>
Link: https://lore.kernel.org/r/20240725-nolibc-s

tools/nolibc: add stdbool.h header

stdbool.h is very simple.
Provide an implementation for the user convenience.

Acked-by: Willy Tarreau <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Thomas Weißschuh <[email protected]>

show more ...

tools/nolibc: add stdarg.h header

This allows nolic to work with `-nostdinc` avoiding any reliance on
system headers.

The implementation has been lifted from musl libc 1.2.4.
There is already an im

tools/nolibc: add stdarg.h header

This allows nolic to work with `-nostdinc` avoiding any reliance on
system headers.

The implementation has been lifted from musl libc 1.2.4.
There is already an implementation of stdarg.h in include/linux/stdarg.h
but that is GPL licensed and therefore not suitable for nolibc.

The used compiler builtins have been validated to be at least available
since GCC 4.1.2 and clang 3.0.0.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>

show more ...

tools/nolibc: add new crt.h with _start_c

As the environ and _auxv support added for nolibc, the assembly _start
function becomes more and more complex and therefore makes the porting
of nolibc to n

tools/nolibc: add new crt.h with _start_c

As the environ and _auxv support added for nolibc, the assembly _start
function becomes more and more complex and therefore makes the porting
of nolibc to new architectures harder and harder.

To simplify portability, this C version of _start_c() is added to do
most of the assembly start operations in C, which reduces the complexity
a lot and will eventually simplify the porting of nolibc to the new
architectures.

The new _start_c() only requires a stack pointer argument, it will find
argc, argv, envp/environ and _auxv for us, and then call main(),
finally, it exit() with main's return status. With this new _start_c(),
the future new architectures only require to add very few assembly
instructions.

As suggested by Thomas, users may use a different signature of main
(e.g. void main(void)), a _nolibc_main alias is added for main to
silence the warning about potential conflicting types.

As suggested by Willy, the code is carefully polished for both smaller
size and better readability with local variables and the right types.

Suggested-by: Willy Tarreau <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Suggested-by: Thomas Weißschuh <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Zhangjin Wu <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>

show more ...

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 an

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 <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: reformat list of headers to be installed

This makes it easier to add and remove more entries in the future
without creating spurious diff hunks.

Signed-off-by: Thomas Weißschuh <linux

tools/nolibc: reformat list of headers to be installed

This makes it easier to add and remove more entries in the future
without creating spurious diff hunks.

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: add support for stack protector

This is useful when using nolibc for security-critical tools.
Using nolibc has the advantage that the code is easily auditable and
sandboxable with secc

tools/nolibc: add support for stack protector

This is useful when using nolibc for security-critical tools.
Using nolibc has the advantage that the code is easily auditable and
sandboxable with seccomp as no unexpected syscalls are used.
Using compiler-assistent stack protection provides another security
mechanism.

For this to work the compiler and libc have to collaborate.

This patch adds the following parts to nolibc that are required by the
compiler:

* __stack_chk_guard: random sentinel value
* __stack_chk_fail: handler for detected stack smashes

In addition an initialization function is added that randomizes the
sentinel value.

Only support for global guards is implemented.
Register guards are useful in multi-threaded context which nolibc does
not provide support for.

Link: https://lwn.net/Articles/584225/

Signed-off-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: add stdint.h

Nolibc works fine for small and limited program however most program
expect integer types to be defined in stdint.h rather than std.h.

This is a quick fix that moves the

tools/nolibc: add stdint.h

Nolibc works fine for small and limited program however most program
expect integer types to be defined in stdint.h rather than std.h.

This is a quick fix that moves the existing integer definitions in std.h
to stdint.h.

Signed-off-by: Vincent Dagonneau <[email protected]>
Reviewed-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: add a help target to list supported targets

The "help" target simply presents the list of supported targets
and the current set of variables being used to build the sysroot.

Since the

tools/nolibc: add a help target to list supported targets

The "help" target simply presents the list of supported targets
and the current set of variables being used to build the sysroot.

Since the help in tools/ suggests to use "install", which is
supported by most tools while such a target is not really relevant
here, an "install" target was also added, redirecting to "help".

Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: make the default target build the headers

The help in "make -C tools" enumerates nolibc as a valid target so we
must at least make it do something. Let's make it do the equivalent
of "

tools/nolibc: make the default target build the headers

The help in "make -C tools" enumerates nolibc as a valid target so we
must at least make it do something. Let's make it do the equivalent
of "make headers" in that it will prepare a sysroot with the arch's
headers, but will not install the kernel's headers. This is the
minimum some tools will need when built with a full-blown toolchain
anyway.

Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: fix the makefile to also work as "make -C tools ..."

As reported by Linus, the nolibc's makefile is currently broken when
invoked as per the documented method (make -C tools nolibc_<ta

tools/nolibc: fix the makefile to also work as "make -C tools ..."

As reported by Linus, the nolibc's makefile is currently broken when
invoked as per the documented method (make -C tools nolibc_<target>),
because it now relies on the ARCH and OUTPUT variables that are not
set in this case.

This patch addresses this by sourcing subarch.include, and by
presetting OUTPUT to the current directory if not set. This is
sufficient to make the commands work both as a standalone target
and as a tools/ sub-target.

Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...

tools/nolibc: add a makefile to install headers

This provides a target "headers_standalone" which installs the nolibc's
arch-specific headers with "arch.h" taken from the current arch (or a
concaten

tools/nolibc: add a makefile to install headers

This provides a target "headers_standalone" which installs the nolibc's
arch-specific headers with "arch.h" taken from the current arch (or a
concatenation of both i386 and x86_64 for arch=x86), then installs
kernel headers. This creates a convenient sysroot which is directly
usable by a bare-metal compiler to create any executable.

Signed-off-by: Willy Tarreau <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

show more ...