Commit Graph

485 Commits

Author SHA1 Message Date
Stefan Eissing
a28540787c
asyn-ares: connect async
Make separate queries for A and AAAA records. Hand out A/AAAA/HTTPS
information before all queries are complete.

Closes #21205
2026-04-09 09:32:12 +02:00
Stefan Eissing
2b3dfb4ad4
lib: make resolving HTTPS DNS records reliable:
- allow to specify when they are wanted on starting a resolve
- match dns cache entries accordingly. An entry which never
  tried to get HTTPS-RRs is no answer for a resolve that wants
  it.
- fix late arrivals of resolve answers to match the "async"
  records that started them - if it still exists.
- provide for multiple "async" resolves in a transfer at the
  same time. We may need to resolve an IP interface while the
  main connection resolve has not finished yet.
- allow lookup of HTTPS-RR information as soon as it is
  available, even if A/AAAA queries are still ongoing.

For this, the "async" infrastructure is changed:

- Defined bits for DNS queries `CURL_DNSQ_A`, `CURL_DNSQ_AAAA`
  and `CURL_DNSQ_HTTPS`. These replace `ip_version` which says
  nothing about HTTPS.
  Use them in dns cache entries for matching.
- enhance the `async->id` to be a unique `uint32_t` for
  resolves inside one multi. This is weak, as the id may
  wrap around. However it is combined with the `mid` of
  the easy handle, making collisions highly unlikely.
  `data->state.async` is only accessed in few places where
  the mid/async-id match is performed.
- vtls: for ECH supporting TLS backends (openssl, rustls, wolfssl),
  retrieve the HTTPS-RR information from the dns connection filter.
  Delay the connect if the HTTPS-RR is needed, but has not
  been resolved yet.

The implementation of all this is complete for the threaded
resolver. c-ares resolver and DoH do not take advantage of
all new async features yet. To be done in separate PRs.

Details:

c-ares: cleanup settings and initialisation. Any ares channel
is only being created on starting a resolve and propagating
operations in setopt.c to the channel are not helpful.

Changed threaded+ares pollset handling so that they do not
overwrite each others `ASYNC_NAME` timeouts.

Add trace name 'threads' for tracing thread queue and
pool used by threaded resolver.

Closes #21175
2026-04-01 15:36:31 +02:00
Stefan Eissing
335dc0e3c5
cf-dns: connection filter for DNS queries
New connection filter `cf-dns` that manages DNS queries. If hands
out addresses and HTTPS-RR records to anyone interested. Used by
HTTPS and IP happy eyeballing.

Information may become available *before* the libcurl "dns entry"
is complete, e.g. all queries have been answered. The cf-ip-happy
filter uses this information to start connection attempts as soon
as the first address is available.

The multi MSTATE_RESOLVING was removed. A new connection always
goes to MSTATE_CONNECTING. The connectdata bit `dns_resolved`
indicates when DNS information is complete. This is used for
error reporting and starting the progress meter.

Removed dns entries `data->state.dns[i]`, as the `cf-dns` filter
now keeps the reference now.

Many minor tweaks for making this work and pass address information
around safely.

Closes #21027
2026-03-30 13:28:38 +02:00
Stefan Eissing
39036c9021
async-thrdd: use thread queue for resolving
Use a thread queue and pool for asnyc threaded DNS resolves.
Add pytest test_21_* for verification.

Add `CURLMOPT_RESOLVE_THREADS_MAX` to allow applications to
resize the thread pool used.

Add `CURLMOPT_QUICK_EXIT` to allow applications to skip thread
joins when cleaning up a multi handle. Multi handles in
`curl_easy_perform()` inherit this from `CURLOPT_QUICK_EXIT`.

Add several debug environment variables for testing.

Closes #20936
2026-03-25 12:14:21 +01:00
Viktor Szakats
6c64d39dce
hostip: drop guard from Curl_resolver_error() definition
To sync with its declaration.

Fixing (seen when building trurl in curl-for-win):
```
ld.lld: error: undefined symbol: Curl_resolver_error
```
Ref: https://github.com/curl/curl-for-win/actions/runs/23388349475/job/68038915761#step:3:7469

Closes #21054
2026-03-21 22:42:38 +01:00
Stefan Eissing
82009c4220
share: concurrency handling, easy updates
Replace the `volatile int dirty` with a reference counter
protected by a mutex when available.

Solve the problem of when to call application's lock function
by adding a volatile flag that indicates a share has been added
to easy handles in its lifetime. That flag ever goes from
FALSE to TRUE, so volatile might work (in the absence of a mutex).

(The problem is that the lock/unlock functions need 2-3
`curl_share_setopt()` invocations to become usable and there
is no way of telling if the third will ever happen. Calling
the lock function before the 3rd setopt may crash the
application.)

When removing a share from an easy handle (or replacing it with
another share), detach the easy connection on a share with a
connection pool.

When cleaning up a share, allow this even if it is still used in
easy handles. It will be destroyed when the reference count
drops to 0.

Closes #20870
2026-03-21 14:42:49 +01:00
Stefan Eissing
745344ea4e
hostip: fix !no_signal mixup in resolve refaactor
When extracting the resolve case using alarm timers, the check for "we
are not allowed to use signals" was refactored wrong.

Follow-up to 96d5b5c688

Closes #21047
2026-03-21 14:28:54 +01:00
Stefan Eissing
96d5b5c688
dnscache: own source file, improvements
- Rename `Curl_resolv_unlink()` to `Curl_dns_entry_unlink()`.
- Change `Curl_dnscache_get()` to return CURLcode result. Returns
  now `CURLE_COULDNT_RESOLVE_HOST` for "negative" cache entries.
- Add `Curl_dnscache_add_negative()` to put a "negative" entry
  into the cache.

Closes #20864
2026-03-21 12:04:36 +01:00
Daniel Stenberg
c0f17dee36
hostip: remove two zero assigns after memset clear
As the struct is now always unconditionally memset with zeros, we
can remove two zero assigns.

Follow-up to 015f1c7de4

Pointed out by CodeSonar

Closes #20900
2026-03-12 08:47:02 +01:00
Vladimír Marek
015f1c7de4
hostip: clear the sockaddr_in6 structure before use
On Solaris this was causing intermittent issues when the private
structure member __sin6_src_id had unexpectedly some value. connect(2)
would then fail with EADDRNOTAVAIL.

Closes #20885
2026-03-11 11:33:13 +01:00
Daniel Stenberg
b4dba346cd
stop using the word 'just'
Everywhere. In documentation and code comments.

It is almost never a good word and almost always a filler that should be
avoided.

Closes #20793
2026-03-03 15:30:22 +01:00
Viktor Szakats
c878160e9c
clang-tidy: sync argument names in prototype and definition
Discovered with clang-tidy checker
`readability-inconsistent-declaration-parameter-name`.

Also:
- do not enforce the above because of inconsistencies still present
  between public API prototypes and definitions. (Also betwen man page
  protos, and man page examples, and other parts of the code, e.g.
  `easy` vs `curl` vs `d` vs `handle`) Perhaps subject for a future
  effort:
  https://github.com/curl/curl/actions/runs/22166472728/job/64094691653
- enable and fix `readability-named-parameter` where missing.

Refs:
https://clang.llvm.org/extra/clang-tidy/checks/readability/inconsistent-declaration-parameter-name.html
https://clang.llvm.org/extra/clang-tidy/checks/readability/named-parameter.html

Closes #20624
2026-02-19 12:44:37 +01:00
Stefan Eissing
ffdbc04c7b
hostip.c: fix leak of addrinfo
When creating a dns entry, the addrinfo is passed into the entry on
success and needed deallocation by the caller on failure.

Change the signature to have Curl_dnscache_mk_entry() *always* take
ownership of the addrinfo, even on failure. Change parameter to address
of pointer so that call always clears it.

This makes the handling of failures to Curl_dnscache_mk_entry() simpler.

Fixes #20465
Closes #20468
2026-02-02 23:29:45 +01:00
Viktor Szakats
9630593650
build: use more const
Mostly with `char *` types.

Also:
- mime, x509asn1, tool_operate, lib3207: drop redundant casts.
- examples/smooth-gtk-thread: add missing variable declaration.
- reduce variable scopes.
- tests/server: move `data_to_hex()` to its only user: `sws`.

Closes #20489
2026-02-02 12:32:49 +01:00
Viktor Szakats
61093e2a81
build: fully omit verbose strings and code when disabled
When the compiler supports C99.

- map logging functions to macro stubs when verbose logging is disabled
  and the compiler is C99. Make sure these stubs silence unused variable
  warnings for non-variadic arguments.
  Before this patch they mapped to function stubs, the same codepath
  used for C89 compiler in this configuration.

- introduce new macros to tell the compiler which code to include
  when verbose code is active, or inactive:

  - `CURLVERBOSE`: defined when verbose code is active.
    To enclose blocks of code only used for verbose logging.

  - `VERBOSE(statement);`:
    compile statement when verbose code is active.
    To mark code lines only used for verbose logging.

  - `NOVERBOSE(statement);`:
    compile statement when verbose code is inactive.
    To suppress warnings for arguments passed to logging functions via
    printf masks, e.g. `NOVERBOSE((void)ipaddress);`, yet keeping
    the warning in verbose builds.

  Note these macros are not the same as `CURL_DISABLE_VERBOSE_STRINGS`.
  Verbose code is always active in C89 mode (without variadic macro
  support).

- drop existing uses of `CURL_DISABLE_VERBOSE_STRINGS` where redundant,
  or replace with the above macros. Ending up reducing the number of
  `#ifdef`s, and also the number of lines.

Assisted-by: Daniel Stenberg
Assisted-by: Jay Satiro
Reported-by: Dan Fandrich
Fixes #20341
Refs: #12105 #12167

Closes #20353
2026-01-21 13:18:35 +01:00
Daniel Stenberg
e286589c71
multi: probe for IPv6 functionality in multi_init()
In some legacy systems IPv6 might dynamically work/not work and thus
curl needs to check/probe to see if it should indeed be used.

This change moves the probe that checks for working IPv6 to the multi
handle setup function instead of delaying it to when the first name
resolve is performed. This avoids a later tricky error path if the
socket cannot be created due to OOM.

Closes #20383
2026-01-21 09:38:31 +01:00
Viktor Szakats
066ed13ca4
hostip: omit forward declaration of verbose logging function
Closes #20381
2026-01-21 04:09:11 +01:00
Viktor Szakats
aef128ef50
hostip: fix unreachable code in rare build configuration
with cmake options:
```
-DCMAKE_UNITY_BUILD=OFF -DCURL_DISABLE_HTTP=ON -DENABLE_THREADED_RESOLVER=OFF
```

Fixing (seen with Apple clang 17):
```
lib/hostip.c:939:16: error: code will never be executed [-Werror,-Wunreachable-code]
  940 |       *entry = dns;
      |                ^~~
```

Closes #20344
2026-01-18 12:45:39 +01:00
Viktor Szakats
57ff2d6c91
dns: flatten the include tree
Closes #20106
2026-01-17 11:45:18 +01:00
Viktor Szakats
60f9d3dd7b
build: omit forward declarations
- drop redundant forward declarations.
- reorder local functions to not need forward declarations.
- tftpd: merge two `ifdef` blocks.

Closes #20297
2026-01-13 21:15:36 +01:00
Viktor Szakats
258521e170
hostip.h: drop redundant setjmp.h include
Already included directly via `hostip.c`, and other header users do not
use it.

Also add comment about why `setjmp.h` is used.

Cherry-picked from #20106

Closes #20132
2025-12-31 17:00:57 +01:00
Viktor Szakats
7032982896
tidy-up: miscellaneous
- asyn-thrdd.c: scope an include.
- apply more clang-format suggestions.
- tidy-up PP guard comments.
- delete empty line from the top of headers.
- add empty line after `curl_setup.h` include where missing.
- fix indent.
- CODE_STYLE.md: add `strcpy`.
  Follow-up to 8636ad55df #20088
- lib1901.c: drop unnecessary line.
  Follow-up to 436e67f65b #20076

Closes #20070
2025-12-26 22:06:09 +01:00
Daniel Stenberg
a535be4ea0
curlx: curlx_strcopy() instead of strcpy()
This function REQUIRES the size of the target buffer as well as the
length of the source string. Meant to make it harder to do a bad
strcpy().

Removes 23 calls to strcpy().

Closes #20067
2025-12-22 23:01:05 +01:00
Viktor Szakats
e8415a8296
lib: drop, or replace sendf.h with curl_trc.h where possible
- replace `sendf.h` with `curl_trc.h` where it was included just for it.
- drop unused `curl_trc.h` includes.
- easy: delete obsolete comment about `send.h` include reason.

Also:
- move out `curl_trc.h` include from `sendf.h` and include it directly
  in users, where not done already. To flatten the include tree and
  to less rely on indirect includes.
- stop including `sendf.h` from other headers, replace it with forward
  declaration of `Curl_easy`, as done already elsewhere.

Verified with an all non-unity CI run.

Closes #20061
2025-12-21 12:39:25 +01:00
Viktor Szakats
884b5ea921
lib: include curlx/warnless.h from curl_setup.h
To make it available for all files. Drop includes from individual
sources. This header was already included from most sources and not
specific to any internal subsystem.

Also to ensure that two system symbol redefines on Windows (`read()` and
`write()`) get applied to all sources. Move them to `curl_setup.h`.

Closes #20056
2025-12-21 02:36:33 +01:00
Stefan Eissing
b4be1f271e
time-keeping: keep timestamp in multi, always update
Always use curlx_now() when calling Curl_pgrs_now(data). Tests with the
"manual" updates to now proved differ more then 100ms in parallel testing.

Add `curlx_nowp()` to set current time into a struct curltime.
Add `curlx_ptimediff_ms() and friends, passing pointers.

Update documentation.

Closes #19998
2025-12-18 22:10:06 +01:00
Stefan Eissing
2de22a00c7
lib: keep timestamp in easy handle
Use `data->progress.now` as the timestamp of proecssing a transfer.
Update it on significant events and refrain from calling `curlx_now()`
in many places.

The problem this addresses is
a) calling curlx_now() has costs, depending on platform. Calling it
   every time results in 25% increase `./runtest` duration on macOS.
b) we used to pass a `struct curltime *` around to save on calls, but
   when some method directly use `curx_now()` and some use the passed
   pointer, the transfer experienes non-linear time. This results in
   timeline checks to report events in the wrong order.

By keeping a timestamp in the easy handle and updating it there, no
longer invoking `curlx_now()` in the "lower" methods, the transfer
can observer a steady clock progression.

Add documentation in docs/internals/TIME-KEEPING.md

Reported-by: Viktor Szakats
Fixes #19935
Closes #19961
2025-12-16 08:48:44 +01:00
Viktor Szakats
0476e4fc65
tidy-up: one more round of formatting nits
Closes #19835
2025-12-04 19:30:59 +01:00
Viktor Szakats
c3b030b860
lib: fix formatting nits (part 3)
From `lib/h` to `lib/w`.

part 1: 47a1ab2ebe #19764
part 2: 86b346443b #19800

Closes #19811
2025-12-03 14:50:16 +01:00
Viktor Szakats
193cb00ce9
build: stop overriding standard memory allocation functions
Before this patch curl used the C preprocessor to override standard
memory allocation symbols: malloc, calloc, strdup, realloc, free.
The goal of these is to replace them with curl's debug wrappers in
`CURLDEBUG` builds, another was to replace them with the wrappers
calling user-defined allocators in libcurl. This solution needed a bunch
of workarounds to avoid breaking external headers: it relied on include
order to do the overriding last. For "unity" builds it needed to reset
overrides before external includes. Also in test apps, which are always
built as single source files. It also needed the `(symbol)` trick
to avoid overrides in some places. This would still not fix cases where
the standard symbols were macros. It was also fragile and difficult
to figure out which was the actual function behind an alloc or free call
in a specific piece of code. This in turn caused bugs where the wrong
allocator was accidentally called.

To avoid these problems, this patch replaces this solution with
`curlx_`-prefixed allocator macros, and mapping them _once_ to either
the libcurl wrappers, the debug wrappers or the standard ones, matching
the rest of the code in libtests.

This concludes the long journey to avoid redefining standard functions
in the curl codebase.

Note: I did not update `packages/OS400/*.c` sources. They did not
`#include` `curl_setup.h`, `curl_memory.h` or `memdebug.h`, meaning
the overrides were never applied to them. This may or may not have been
correct. For now I suppressed the direct use of standard allocators
via a local `.checksrc`. Probably they (except for `curlcl.c`) should be
updated to include `curl_setup.h` and use the `curlx_` macros.

This patch changes mappings in two places:
- `lib/curl_threads.c` in libtests: Before this patch it mapped to
  libcurl allocators. After, it maps to standard allocators, like
  the rest of libtests code.
- `units`: before this patch it mapped to standard allocators. After, it
  maps to libcurl allocators.

Also:
- drop all position-dependent `curl_memory.h` and `memdebug.h` includes,
  and delete the now unnecessary headers.
- rename `Curl_tcsdup` macro to `curlx_tcsdup` and define like the other
  allocators.
- map `curlx_strdup()` to `_strdup()` on Windows (was: `strdup()`).
  To fix warnings silenced via `_CRT_NONSTDC_NO_DEPRECATE`.
- multibyte: map `curlx_convert_*()` to `_strdup()` on Windows
  (was: `strdup()`).
- src: do not reuse the `strdup` name for the local replacement.
- lib509: call `_strdup()` on Windows (was: `strdup()`).
- test1132: delete test obsoleted by this patch.
- CHECKSRC.md: update text for `SNPRINTF`.
- checksrc: ban standard allocator symbols.

Follow-up to b12da22db1 #18866
Follow-up to db98daab05 #18844
Follow-up to 4deea9396b #18814
Follow-up to 9678ff5b1b #18776
Follow-up to 10bac43b87 #18774
Follow-up to 20142f5d06 #18634
Follow-up to bf7375ecc5 #18503
Follow-up to 9863599d69 #18502
Follow-up to 3bb5e58c10 #17827

Closes #19626
2025-11-28 10:44:26 +01:00
Daniel Stenberg
31b1527c1d
hostip: only store negative response for CURLE_COULDNT_RESOLVE_HOST
Follow-up from ce06fe7771

This allows us to drop the 'keep_negative' variable completely.

Closes #19701
2025-11-25 23:36:31 +01:00
Daniel Stenberg
ce06fe7771
hostip: make more functions return CURLcode
- Curl_async_getaddrinfo() always returned NULL so it was pointless.
  Return proper curlcode instead to distinguish between errors. Same for
  Curl_doh().
- simplify the IP address handling
- make Curl_str2addr() function return CURLcode

Closes #19669
2025-11-25 09:13:34 +01:00
Viktor Szakats
3887069c66
lib: rename internal header share.h to curl_share.h to avoid collision
Windows CRTs have a `share.h`. Before this patch when trying to
`#include <share.h>` it, the compiler picked up curl's internal
`lib/share.h` instead. Rename it to avoid this issue.

CRT `share.h` has constants necessary for using safe open CRT functions.

Also rename `lib/share.c` to keep matching the header.

Ref: https://learn.microsoft.com/cpp/c-runtime-library/sharing-constants
Ref: 625f2c1644 #16949 #16991
Cherry-picked from #19643
Closes #19676
2025-11-25 00:26:50 +01:00
Viktor Szakats
554dfa5568
build: drop Windows CE / CeGCC support
Windows CE support was limited to successful builds with ming32ce
(a toolchain that hasn't seen an update since 2009, using an ancient gcc
version and "old mingw"-style SDK headers, that curl deprecated earlier).
Builds with MSVC were broken for a long time. mingw32ce builds were never
actually tested and runtime and unlikely to work due to missing stubs.
Windows CE toolchains also miss to comply with C89. Paired with lack of
demand and support for the platform, curl deprecated it earlier.

This patch removes support from the codebase to ease maintaining Windows
codepaths.

Follow-up to f98c0ba834 #17924
Follow-up to 8491e6574c #17379
Follow-up to 2a292c3984 #15975

Closes #17927
2025-11-15 15:35:23 +01:00
Viktor Szakats
2dc71ba8bf
badwords: check indented lines in source code, fix fallouts
- badwords.pl: add `-a` option to check all lines in source code files.
  Before this patch indented lines were skipped (to avoid Markdown code
  fences.)
- GHA/checksrc: use `-a` when verifying the source code.
- GHA/checksrc: disable `So` and `But` rules for source code.
- GHA/checksrc: add docs/examples to the verified sources.
- badwords.txt: delete 4 duplicates.
- badwords.txt: group and sort contractions.
- badwords.txt: allow ` url = `, `DIR`, `<file name`.

Closes #19536
2025-11-15 13:25:02 +01:00
Stefan Eissing
78a610cb83
lib: rename curlx_timediff to curlx_timeleft_ms
Rename `Curl_timeleft()` to `Curl_timeleft_ms()` to make the units in
the returned `timediff_t` clear. (We used to always have ms there, but
with QUIC started to sometimes calc ns as well).

Rename some assigned vars without `_ms` suffix for clarity as well.

Closes #19486
2025-11-13 13:12:58 +01:00
Daniel Stenberg
a862920246
hostip: don't store negative lookup on OOM
When convert_ipaddr_direct() returns error due to OOM, it must not be
stored as a negative cache result.

Closes #19484
2025-11-12 12:19:12 +01:00
x2018
02113a6307
Curl_resolv: explicitly set *entry to NULL at the top
Closes #19263
2025-10-28 11:39:13 +01:00
Daniel Stenberg
7295546447
hostip: fix infof() output for non-ipv6 builds using IPv6 address
Pointed out by ZeroPath

Closes #19184
2025-10-22 08:41:19 +02:00
Daniel Stenberg
7f19fa9819
lib: add asserts that hostname has content
For all network related protocols there must be a non-blank hostname
used. This change adds a few asserts in some places to make debug/tests
catch mistakes if any such would slip in.

Closes #19146
2025-10-19 23:45:28 +02:00
Daniel Stenberg
435da1f849
Curl_resolv: fix comment. 'entry' argument is not optional
Reported-by: Joshua Rogers
Closes #18979
2025-10-09 22:03:19 +02:00
Daniel Stenberg
b0db5f12b1
hostip: don't store negative resolves due unrelated errors
Like for:

- OOM
- resolver_start() returns error
- DoH has problems

Fixes #18953
Fixes #18954
Reported-by: Joshua Rogers
Closes #18958
2025-10-09 10:50:56 +02:00
Viktor Szakats
b12da22db1
lib: stop overriding system printf symbols
After this patch, the codebase no longer overrides system printf
functions. Instead it explicitly calls either the curl printf functions
`curl_m*printf()` or the system ones using their original names.

Also:
- drop unused `curl_printf.h` includes.
- checksrc: ban system printf functions, allow where necessary.

Follow-up to db98daab05 #18844
Follow-up to 4deea9396b #18814

Closes #18866
2025-10-06 20:57:59 +02:00
Daniel Stenberg
470611d76c
hostip: remove unnecessary leftover INT_MAX check in Curl_dnscache_prune
The math already uses timediff_t so no need for the extra logic

Ref: #18678
Closes #18680
2025-09-24 14:11:36 +02:00
Viktor Szakats
bf7375ecc5
build: avoid overriding system symbols for socket functions
Before this patch `accept4()`, `socket()`, `socketpair()`, `send()` and
`recv()` system symbols were remapped via macros, using the same name,
to local curl debug wrappers. This patch replaces these overrides by
introducing curl-namespaced macros that map either to the system symbols
or to their curl debug wrappers in `CURLDEBUG` (TrackMemory) builds.

This follows a patch that implemented the same for `accept()`.

The old method required tricks to make these redefines work in unity
builds, and avoid them interfering with system headers. These tricks
did not work for system symbols implemented as macros.

The new method allows to setup these mappings once, without interfering
with system headers, upstream macros, or unity builds. It makes builds
more robust.

Also:
- checksrc: ban all mapped functions.
- docs/examples: tidy up checksrc rules.

Follow-up to 9863599d69 #18502
Follow-up to 3bb5e58c10 #17827

Closes #18503
2025-09-20 13:44:59 +02:00
Stefan Eissing
de3fc1d7ad
asyn-thrdd: drop pthread_cancel
Remove use of pthread_cancel in asnyc threaded resolving. While there
are system where this works, others might leak to resource leakage
(memory, files, etc.). The popular nsswitch is one example where resolve
code can be dragged in that is not prepared.

The overall promise and mechanism of pthread_cancel() is just too
brittle and the historcal design of getaddrinfo() continues to haunt us.

Fixes #18532
Reported-by: Javier Blazquez
Closes #18540
2025-09-15 09:25:43 +02:00
Viktor Szakats
49145249be
tidy-up: drop stray "unused" comments
Closes #18453
2025-09-03 16:31:16 +02:00
Stefan Eissing
6b111f0a8c
ares: use ares_strerror() to retrieve error messages
Add optional detail to `Curl_resolver_error()` to add to failure message
where available. This makes, for c-ares, the reason for a failed
resource available to the user without extra trace config.

When "dns" tracing enabled, print the c-ares server config at the start
of a resolve.

Closes #18251
2025-08-22 10:01:58 +02:00
Stefan Eissing
88fc6c491f
threaded-resolver: fix shutdown
Changed strategy to start up and terminate resolver thread.

When starting up:

Start the thread with mutex acquired, wait for signal from thread that
it started and has incremented the ref counter. Thread set
pthread_cancel() to disabled before that and only enables cancelling
during resolving itself. This assure that the ref counter is correct and
the unlinking of the resolve context always happens.

When shutting down resolving:

If ref counting shows thread has finished, join it, free everything. If
thread has not finished, try pthread_cancel() (non Windows), but keep
the thread handle around.

When destroying resolving:

Shutdown first, then, if the thread is still there and 'quick_exit' is
not set, join it and free everything. This might occur a delay if
getaddrinfo() hangs and cannot be interrupted by pthread_cancel().

Destroying resolving happens when another resolve is started on an
easy handle or when the easy handle is closed.

Add test795 to check that connect timeout triggers correctly
when resolving is delayed. Add debug env var `CURL_DNS_DELAY_MS`
to simulate delays in resolving.

Fix test1557 to set `quick_exit` and use `xxx.invalid` as domain
instead of `nothing` that was leading to hangers in CI.

Closes #18263
2025-08-21 09:26:49 +02:00
Stefan Eissing
9cc4e24ad9
resolving: dns error tracing
* Add more tracing information to c-ares errors.
* remove CURL_ASYNC_SUCCESS, rename `ares->last_status` to
  `ares->ares_status`. Give trace explanation for "common"
  errors
* add ares "csv" information to tracing on failure
* DoH: invoke `Curl_resolver_error()` on failure to populate
  error buf

Closes #18247
2025-08-11 14:35:07 +02:00