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From: Carlos O'Donell <carlos@redhat.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	libc-alpha@sourceware.org
Subject: Re: [PATCH 01/28] elf: Do not search HWCAP subdirectories in statically linked binaries
Date: Thu, 1 Oct 2020 16:24:28 -0400	[thread overview]
Message-ID: <0c038109-32ac-5a69-d3c0-525f4111ced6@redhat.com> (raw)
In-Reply-To: <1818e0ce-25da-a7a0-aaca-475b15874e8c@linaro.org>

On 10/1/20 2:29 PM, Adhemerval Zanella wrote:
> 
> 
> On 01/10/2020 15:24, Carlos O'Donell wrote:
>> On 10/1/20 2:22 PM, Adhemerval Zanella via Libc-alpha wrote:
>>>
>>>
>>> On 01/10/2020 13:31, Florian Weimer via Libc-alpha wrote:
>>>> This functionality does not seem to be useful since static dlopen
>>>> is mostly used for iconv/character set conversion and NSS support.
>>>> gconv modules are loaded with full paths anyway, so that the
>>>> HWCAP subdirectory logic does not apply.
>>>
>>> This change looks reasonable, although it makes the semantic of 
>>> statically linked programs slight different than dynamic one regarding
>>> dlopen.
>>
>> I think this is OK.
>>
>> dlopen from statically linked programs is deprecated, the only uses
>> should be internal to glibc in NSS And iconv.
>>
>> We really really want:
>>
>> * Just a statically linked program that has no external deps.
>>
>> * Just a dynamically linked program can support dlopen.
>>
>> This half-way inbetween support we have has serious consequences,
>> and is the reason I supported us deprecating dlopen from static
>> binaries. Users should not be allowed to shoot themselves in
>> the foot.
>>
>> $0.02.
>>
> 
> I agree, usually on discussion about static linking with glibc users
> get perplexed why shared libraries are being loaded under the hood
> and usually this is a deal breaker on most usercases (another one
> is the minimum kernel requirement).
 Fixing the dlopen case requires splitting the interface at the NSS
boundary (as Florian suggested?) and calling out from the static
binary to some kind of 'getent'-like binary, perhaps even getent
itself in compat cases.

The minimum kernel requirement is much easier to explain. We have
a minimum requirement. I find users get that when it's explained
clearly.

-- 
Cheers,
Carlos.


  reply	other threads:[~2020-10-01 20:24 UTC|newest]

Thread overview: 103+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-01 16:31 [PATCH 00/28] glibc-hwcaps support Florian Weimer
2020-10-01 16:31 ` [PATCH 01/28] elf: Do not search HWCAP subdirectories in statically linked binaries Florian Weimer
2020-10-01 18:22   ` Adhemerval Zanella
2020-10-01 18:24     ` Carlos O'Donell
2020-10-01 18:29       ` Adhemerval Zanella
2020-10-01 20:24         ` Carlos O'Donell [this message]
2020-10-01 16:31 ` [PATCH 02/28] elf: Implement __rtld_malloc_is_full Florian Weimer
2020-10-01 18:23   ` Adhemerval Zanella
2020-10-08  9:44     ` Florian Weimer
2020-10-01 16:31 ` [PATCH 03/28] elf: Implement _dl_write Florian Weimer
2020-10-05 19:46   ` Adhemerval Zanella
2020-10-01 16:31 ` [PATCH 04/28] elf: Extract command-line/environment variables state from rtld.c Florian Weimer
2020-10-06 20:45   ` Adhemerval Zanella
2020-10-08 11:32     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 05/28] elf: Move ld.so error/help output to _dl_usage Florian Weimer
2020-10-06 21:06   ` Adhemerval Zanella
2020-10-08 12:19     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 06/28] elf: Record whether paths come from LD_LIBRARY_PATH or --library-path Florian Weimer
2020-10-07 16:39   ` Adhemerval Zanella
2020-10-07 16:49     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 07/28] elf: Implement ld.so --help Florian Weimer
2020-10-07 17:16   ` Adhemerval Zanella
2020-10-08 13:13     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 08/28] elf: Implement ld.so --version Florian Weimer
2020-10-07 18:36   ` Adhemerval Zanella
2020-10-07 18:38     ` Adhemerval Zanella
2020-10-08 13:37     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 09/28] scripts/update-copyrights: Update csu/version.c, elf/dl-usage.c Florian Weimer
2020-10-07 18:41   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 10/28] elf: Use the term "program interpreter" in the ld.so help message Florian Weimer
2020-10-07 21:08   ` Adhemerval Zanella
2020-10-08 14:08     ` Florian Weimer
2020-10-01 16:32 ` [PATCH 11/28] elf: Print the full name of the dynamic loader " Florian Weimer
2020-10-08 12:38   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 12/28] elf: Make __rtld_env_path_list and __rtld_search_dirs global variables Florian Weimer
2020-10-08 13:27   ` Adhemerval Zanella
2020-10-01 16:32 ` [PATCH 13/28] elf: Add library search path information to ld.so --help Florian Weimer
2020-10-08 16:22   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 14/28] elf: Enhance ld.so --help to print HWCAP subdirectories Florian Weimer
2020-10-08 16:27   ` Adhemerval Zanella
2020-10-09  8:18     ` Florian Weimer
2020-10-09 13:49   ` Matheus Castanho
2020-10-09 17:08     ` Florian Weimer
2020-10-09 17:12       ` Florian Weimer
2020-10-09 18:54         ` Matheus Castanho
2020-10-12  9:47           ` Florian Weimer
2020-10-01 16:33 ` [PATCH 15/28] elf: Do not pass GLRO(dl_platform), GLRO(dl_platformlen) to _dl_important_hwcaps Florian Weimer
2020-10-08 18:04   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 16/28] elf: Add glibc-hwcaps support for LD_LIBRARY_PATH Florian Weimer
2020-10-08 10:13   ` Szabolcs Nagy
2020-10-09  9:08     ` Florian Weimer
2020-10-09 10:50       ` Szabolcs Nagy
2020-10-09 10:55         ` Florian Weimer
2020-10-09 11:03           ` Szabolcs Nagy
2020-10-08 23:16   ` Paul A. Clarke
2020-10-09  8:56     ` Florian Weimer
2020-10-09 13:19   ` Adhemerval Zanella
2020-10-12 11:54     ` Florian Weimer
2020-10-01 16:33 ` [PATCH 17/28] x86_64: Add glibc-hwcaps support Florian Weimer
2020-10-01 16:33 ` [PATCH 18/28] powerpc64le: " Florian Weimer
2020-10-01 18:56   ` Paul A. Clarke
2020-10-05  9:47     ` Florian Weimer
2020-10-05 19:15       ` Paul A. Clarke
2020-10-06 12:20         ` Florian Weimer
2020-10-06 17:45           ` Paul A. Clarke
2020-10-09  9:06             ` Florian Weimer
2020-10-01 16:33 ` [PATCH 19/28] s390x: Add " Florian Weimer
2020-10-01 16:33 ` [PATCH 20/28] aarch64: " Florian Weimer
2020-10-14 13:46   ` Adhemerval Zanella
2020-10-14 14:08     ` Florian Weimer
2020-10-14 14:15       ` Adhemerval Zanella
2020-10-14 14:37         ` Szabolcs Nagy
2020-10-14 14:43           ` Adhemerval Zanella
2020-10-14 15:13             ` Florian Weimer
2020-10-14 14:44           ` Florian Weimer
2020-10-14 15:09             ` Szabolcs Nagy
2020-10-01 16:33 ` [PATCH 21/28] elf: Add endianness markup to ld.so.cache Florian Weimer
2020-10-14 14:07   ` Adhemerval Zanella
2020-10-01 16:33 ` [PATCH 22/28] elf: Add extension mechanism " Florian Weimer
2020-10-15 17:52   ` Adhemerval Zanella
2020-10-30 12:22     ` Florian Weimer
2020-11-03 12:45       ` Adhemerval Zanella
2020-11-03 15:30         ` Florian Weimer
2020-10-01 16:34 ` [PATCH 23/28] elf: Unify old and new format cache handling code in ld.so Florian Weimer
2020-10-16 14:37   ` Adhemerval Zanella
2020-10-30 13:22     ` Florian Weimer
2020-11-03 13:02       ` Adhemerval Zanella
2020-10-01 16:34 ` [PATCH 24/28] elf: Implement a string table for ldconfig, with tail merging Florian Weimer
2020-10-20 14:25   ` Adhemerval Zanella
2020-10-30 17:08     ` Florian Weimer
2020-11-03 13:05       ` Adhemerval Zanella
2020-11-03 15:29         ` Florian Weimer
2020-10-01 16:34 ` [PATCH 25/28] elf: Implement tail merging of strings in ldconfig Florian Weimer
2020-10-22 21:08   ` Adhemerval Zanella
2020-10-30 17:36     ` Florian Weimer
2020-10-01 16:34 ` [PATCH 26/28] elf: In ldconfig, extract the new_sub_entry function from search_dir Florian Weimer
2020-10-27 13:15   ` Adhemerval Zanella
2020-10-01 16:34 ` [PATCH 27/28] elf: Process glibc-hwcaps subdirectories in ldconfig Florian Weimer
2020-10-27 17:28   ` Adhemerval Zanella
2020-11-04 11:57     ` Florian Weimer
2020-10-01 16:34 ` [PATCH 28/28] elf: Add glibc-hwcaps subdirectory support to ld.so cache processing Florian Weimer
2020-10-01 16:50 ` [PATCH 00/28] glibc-hwcaps support H.J. Lu
2020-10-01 16:54   ` Florian Weimer

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