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boundary="------------Lzv0HbUPiLaqwaTtWCEXAQwd" Message-ID: <8a34573d-4a6c-4d5d-a771-b39279059547@gmail.com> Date: Sat, 3 Feb 2024 17:11:42 +0100 List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: libc/libsys split coming soon To: freebsd-current@freebsd.org References: Content-Language: en-US From: Paul Floyd In-Reply-To: X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.99 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20230601]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; XM_UA_NO_VERSION(0.01)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FREEMAIL_ENVFROM(0.00)[gmail.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FREEMAIL_FROM(0.00)[gmail.com]; RCPT_COUNT_ONE(0.00)[1]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; TO_DN_NONE(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; PREVIOUSLY_DELIVERED(0.00)[freebsd-current@freebsd.org]; MID_RHS_MATCH_FROM(0.00)[]; MLMMJ_DEST(0.00)[freebsd-current@freebsd.org]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::331:from] X-Rspamd-Queue-Id: 4TRyM614gfz4QT5 This is a multi-part message in MIME format. --------------Lzv0HbUPiLaqwaTtWCEXAQwd Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 02/02/2024 23:31, Brooks Davis wrote: > TL;DR: The implementation of system calls is moving to a seperate > library (libsys). No changes are required to existing software (except > to ensure that libsys is present when building custom disk images). > > Code:https://github.com/freebsd/freebsd-src/pull/908 > > After nearly a decade of intermittent work, I'm about to land a series > of patches which moves system calls, vdso support, and libc's parsing of > the ELF auxiliary argument vector into a separate library (libsys). I > plan to do this early next week (February 5th). > > This change serves three primary purposes: > 1. It's easier to completely replace system call implementations for > tracing or compartmentalization purposes. Will that affect code that makes syscalls without currently linking to libc? > 2. It simplifies the implementation of restrictions on system calls such > as those implemented by OpenBSD's msyscall(2) > (https://man.openbsd.org/msyscall.2). That's one to ignore for tools that make syscalls outside of the libc memory mapping. > 3. It allows language runtimes to link with libsys for system call > implementations without requiring libc. I see that pagesize is on the list of functions that are moving. There are a couple of other functions that might cause me problems if libc isn't linked. Could you do a quick test with an exe linked to libsys but not libc running under Valgrind memcheck, please? A+ Paul --------------Lzv0HbUPiLaqwaTtWCEXAQwd Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit


On 02/02/2024 23:31, Brooks Davis wrote:
TL;DR: The implementation of system calls is moving to a seperate
library (libsys).  No changes are required to existing software (except
to ensure that libsys is present when building custom disk images).

Code: https://github.com/freebsd/freebsd-src/pull/908

After nearly a decade of intermittent work, I'm about to land a series
of patches which moves system calls, vdso support, and libc's parsing of
the ELF auxiliary argument vector into a separate library (libsys).  I
plan to do this early next week (February 5th).

This change serves three primary purposes:
  1. It's easier to completely replace system call implementations for
     tracing or compartmentalization purposes.

Will that affect code that makes syscalls without currently linking to libc? 

  2. It simplifies the implementation of restrictions on system calls such
     as those implemented by OpenBSD's msyscall(2)
     (https://man.openbsd.org/msyscall.2).

That's one to ignore for tools that make syscalls outside of the libc memory mapping. 

  3. It allows language runtimes to link with libsys for system call
     implementations without requiring libc.

I see that pagesize is on the list of functions that are moving. There are a couple of other functions that might cause me problems if libc isn't linked.

Could you do a quick test with an exe linked to libsys but not libc running under Valgrind memcheck, please?

A+

Paul

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