Protocol handlers not flagging PROTOPT_SSL that allow reuse of existing
SSL connections now need to carry the flag PROTOPT_SSL_REUSE.
Add PROTOPT_SSL_REUSE to imap, ldap, pop3, smtp and ftp.
Add tests the http: urls do not reuse https: connections and vice versa.
Reported-by: Sakthi SK
Fixes#19006Closes#19007
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#18814Closes#18866
- fix `CURLcode` vs. LDAP result code confusion.
Return `LDAP_NO_MEMORY` when `Curl_create_sspi_identity()` fails,
since it can only return `CURLE_OUT_OF_MEMORY` as error.
- use `ULONG` for result code on Windows. Drop casts.
- use portable `curl_ldap_num_t`. Drop casts.
- replace magic number 0 with `LDAP_SUCCESS`.
- compare with `LDAP_SUCCESS` instead of assuming non-zero.
(where necessary.)
- add/fix `#endif` comments.
- fix indentation.
Closes#18888
`-Weverything` is not enabled by curl, and not recommended by LLVM,
because it may enable experimental options, and will result in new
fallouts after toolchain upgrades. This patch aims to fix/silence as much
as possible as found with llvm/clang 21.1.0. It also permanently enables
warnings that were fixed in source and deemed manageable in the future.
`-Wformat` warnings are addressed separately via #18343.
Fix/silence warnings in the source:
- typecheck-gcc.h: fix `-Wreserved-identifier`.
- lib: silence `-Wcast-function-type-strict`.
For llvm 16+ or Apple clang 16+.
- asyn-ares: limit `HAPPY_EYEBALLS_DNS_TIMEOUT` to old c-ares versions.
- curl_trc: fix `-Wc++-hidden-decl`.
- doh: fix `-Wc++-keyword`.
- ftp: fix `-Wreserved-identifier`.
- ldap: fix `-Wreserved-identifier`.
- mqtt: comment unused macro to avoid warning.
- multi_ev: drop unused macros to avoid warnings.
- setopt: fix useless `break;` after `return;`.
- gtls, mbedtls, rustls: silence `-Wconditional-uninitialized`.
- socks_sspi, schannel, x509asn1: fix `-Wimplicit-int-enum-cast`.
- x509asn1: fix `-Wc++-keyword`.
- openssl: scope `OSSL_UI_METHOD_CAST` to avoid unused macro warning.
- libssh2, wolfssl: drop unused macros.
- curl_ngtcp2, curl_quiche, httpsrr, urlapi: drop/limit unused macros.
- tool_getparam: fix useless `break;` after `return;` or `break;`.
Not normally enabled because it doesn't work with unity.
https://github.com/llvm/llvm-project/issues/71046
- tool_operate: fix `-Wc++-keyword`.
- curlinfo: fix a `-Wunsafe-buffer-usage`.
- tests: silence `-Wformat-non-iso`.
- lib557: fix `-Wreserved-identifier`.
- lib1565: silence `-Wconditional-uninitialized`.
Enable the above clang warnings permanently in picky mode:
- `-Wc++-hidden-decl`
- `-Wc++-keyword` (except for Windows, where it collides with `wchar_t`)
- `-Wcast-function-type-strict`
- `-Wcast-function-type`
- `-Wconditional-uninitialized`
- `-Wformat-non-iso` (except for clang-cl)
- `-Wreserved-identifier`
- `-Wtentative-definition-compat`
Silence problematic `-Weverything` warnings globally (in picky mode):
- `-Wused-but-marked-unused` (88000+ hits) and
`-Wdisabled-macro-expansion` (2600+ hits).
Triggered by `typecheck-gcc.h` when building with clang 14+.
Maybe there exists a way to fix within that header?
Ref: https://discourse.llvm.org/t/removing-wused-but-marked-unused/55310
- `-Wunsafe-buffer-usage`. clang 16+. 7000+ hits.
May be useful in theory, but such high volume of hits makes it
impractical to review and possibly address. Meant for C++.
Ref: https://clang.llvm.org/docs/SafeBuffers.html
Ref: https://stackoverflow.com/questions/77017567/how-to-fix-code-to-avoid-warning-wunsafe-buffer-usage
Ref: https://discourse.llvm.org/t/rfc-c-buffer-hardening/65734
Ref: https://github.com/llvm/llvm-project/pull/111624
- `-Wimplicit-void-ptr-cast`. clang 21+. 1700+ hits.
C++ warning, deemed pure noise.
Ref: https://github.com/curl/curl/issues/18470#issuecomment-3253506266
- `-Wswitch-default` (180+ hits), `-Wswitch-enum` (190+ hits),
`-Wcovered-switch-default` (20+ hits).
Next to impossible to fix cleanly, esp. when the covered `case`
branches depend on compile-time options.
- `-Wdocumentation-unknown-command` (8+ hits).
Triggered in a few sources. Seems arbitrary and bogus.
- `-Wpadded` (550+ hits).
- `-Wc++-keyword` on Windows, where it collides with `wchar_t`.
(100+ hits)
Ref: https://github.com/llvm/llvm-project/issues/155988
- `-Wreserved-macro-identifier`. clang 13+. 5+ hits.
Sometimes it's necessary to set external macros that use
the reserved namespace. E.g. `_CRT_NONSTDC_NO_DEPRECATE`,
`__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__`, `__NO_NET_API`,
possibly `_REENTRANT`, and more.
It's not worth trying to silence them individually.
- `-Wnonportable-system-include-path` with `clang-cl`.
It'd be broken by doing what the warning suggests.
- `-Wformat-non-iso` for clang-cl.
CMake `PICKY_COMPILER=ON` (the default) or `./configure`
`--enable-warnings` (not the default) is required to enable these
silencing rules.
Also:
- autotools, cmake: fix Apple clang and mainline llvm version translations.
Ref: https://en.wikipedia.org/wiki/Xcode#Toolchain_versions
- autotools, cmake: enable `-Warray-compare` for clang 20+.
Follow-up to 4b7accda5a#17196
- cmake: fix to enable `-Wmissing-variable-declarations` at an earlier
clang version.
- cmake: update internal logic to handle warning options with `+` in
them.
- cmake: fix internal logic to match the whole option when looking
into `CMAKE_C_FLAGS` for custom-disabled warnings.
Follow-up to b85cb8cb4e#18485Closes#18477
`getsock()` calls operated on a global limit that could
not be configure beyond 16 sockets. This is no longer adequate
with the new happy eyeballing strategy.
Instead, do the following:
- make `struct easy_pollset` dynamic. Starting with
a minimal room for two sockets, the very common case,
allow it to grow on demand.
- replace all protocol handler getsock() calls with pollsets
and a CURLcode to return failures
- add CURLcode return for all connection filter `adjust_pollset()`
callbacks, since they too can now fail.
- use appropriately in multi.c and multi_ev.c
- fix unit2600 to trigger pollset growth
Closes#18164
Since the content varies during connection setup and while doing it
(eyeballing), remove these strcut from `connectdata` and replace use
with querying the connection filters. Those keep that information
already.
Change the info logging of established connections to also give the
local address and port.
Closes#17960
Drop `strcasecompare` and `strncasecompare` in favor of libcurl API
calls `curl_strequal` and `curl_strnequal` respectively.
Also drop unnecessary `strcase.h` includes. Include `curl/curl.h`
instead where it wasn't included before.
Closes#17772
Move curlx_ functions into its own subdir.
The idea is to use the curlx_ prefix proper on these functions, and use
these same function names both in tool, lib and test suite source code.
Stop the previous special #define setup for curlx_ names.
The printf defines are now done for the library alone. Tests no longer
use the printf defines. The tool code sets its own defines. The printf
functions are not curlx, they are publicly available.
The strcase defines are not curlx_ functions and should not be used by
tool or server code.
dynbuf, warnless, base64, strparse, timeval, timediff are now proper
curlx functions.
When libcurl is built statically, the functions from the library can be
used as-is. The key is then that the functions must work as-is, without
having to be recompiled for use in tool/tests. This avoids symbol
collisions - when libcurl is built statically, we use those functions
directly when building the tool/tests. When libcurl is shared, we
build/link them separately for the tool/tests.
Assisted-by: Jay Satiro
Closes#17253
The issues found fell into these categories, with the applied fixes:
- const was accidentally stripped.
Adjust code to not cast or cast with const.
- const/volatile missing from arguments, local variables.
Constify arguments or variables, adjust/delete casts. Small code
changes in a few places.
- const must be stripped because an API dependency requires it.
Strip `const` with `CURL_UNCONST()` macro to silence the warning out
of our control. These happen at API boundaries. Sometimes they depend
on dependency version, which this patch handles as necessary. Also
enable const support for the zlib API, using `ZLIB_CONST`. Supported
by zlib 1.2.5.2 and newer.
- const must be stripped because a curl API requires it.
Strip `const` with `CURL_UNCONST()` macro to silence the warning out
of our immediate control. For example we promise to send a non-const
argument to a callback, though the data is const internally.
- other cases where we may avoid const stripping by code changes.
Also silenced with `CURL_UNCONST()`.
- there are 3 places where `CURL_UNCONST()` is cast again to const.
To silence this type of warning:
```
lib/vquic/curl_osslq.c:1015:29: error: to be safe all intermediate
pointers in cast from 'unsigned char **' to 'const unsigned char **'
must be 'const' qualified [-Werror=cast-qual]
lib/cf-socket.c:734:32: error: to be safe all intermediate pointers in
cast from 'char **' to 'const char **' must be 'const' qualified
[-Werror=cast-qual]
```
There may be a better solution, but I couldn't find it.
These cases are handled in separate subcommits, but without further
markup.
If you see a `-Wcast-qual` warning in curl, we appreciate your report
about it.
Closes#16142
- add hex and octal parsers to the Curl_str_* family
- make curlx_strtoofft use these parsers
- remove all use of strtol() and strtoul() in library code
- generally use Curl_str_* more than strtoofft, for stricter parsing
- supports 64-bit universally, instead of 'long' which differs in size
between platforms
Extended the unit test 1664 to verify hex and octal parsing.
Closes#16336
The latest copy I could find at:
https://beta.novell.com/developer/ndk/ldap_libraries_for_c.html
is from 2016-Feb-03, available for Linux and Windows.
I built curl against the Windows package with CMake:
https://sdk.suse.com/ndk/cldap/builds/2016/openldapsdk-devel-windows64-2016-01-28.zip
(It comes with OpenSSL 1.0.1q-fips (2015-Dec-03) binaries.)
CMake identified it as OpenLDAP and built with it as expected:
```
curl 8.12.0-DEV (x86_64-w64-mingw32) libcurl/8.12.0-DEV Schannel OpenLDAP/2.4.37
Release-Date: [unreleased]
Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns ldap ldaps mqtt pop3 pop3s rtsp smb smbs smtp smtps telnet tftp ws wss
Features: alt-svc AsynchDNS HSTS HTTPS-proxy IPv6 Kerberos Largefile NTLM SPNEGO SSL SSPI threadsafe UnixSockets
```
Since it identified it as OpenLDAP (`lib/openldap.c`), the branch
deleted in this PR (`lib/ldap.c`) wasn't reached. Thus, defining
the `CURL_HAS_NOVELL_LDAPSDK` also made no difference in the build.
This suggests the code guarded by it is now orphan and unnecessary.
Novell NetWare builds were another user, but we dropped support for them
in 2022: 3b16575ae9#8358Closes#16176
Adds a `follow()` callback to protocol handlers, so they may decide how
to act on a `newurl` after a request has been done. This is optional.
This moves the HTTP code for handling redirects from multi.c to http.c
where it should be. If we ever add a protocol with its own logic, it
would install its own follow function.
Closes#16075
Protocol handler option PROTOPT_SSL is used to setup a connection
filters. Once that is done, used `Curl_conn_is_ssl()` to check if
a connection uses SSL.
There may be other reasons to add SSL to a connection, e.g. starttls.
Closes#16034
On apple builds, the gssapi/ldap/securetransport headers deprecate
almost everything which leads to a wall of compiler warnings on use in
code.
Suppress those warning that may hide other warnings/errors.
Closes#15763
krb5 defines `strtok_r` for Windows unconditionally in its public
header:
dc5554394e/src/include/win-mac.h (L214-L215)
resulting in this warning:
```
lib\strtok.h(31,9): warning C4005: 'strtok_r': macro redefinition
C:\vcpkg\installed\x64-windows\include\win-mac.h(215,9):
see previous definition of 'strtok_r'
```
The krb5 macro collides with curl's internal definition, in case
the `strtok_r` function is undetected and falling back to a local
replacement.
Reported-by: Tal Regev
Bug: https://github.com/curl/curl/pull/15549#issuecomment-2468251761Closes#15564
Use these words and casing more consistently across text, comments and
one curl tool output:
AIX, ALPN, ANSI, BSD, Cygwin, Darwin, FreeBSD, GitHub, HP-UX, Linux,
macOS, MS-DOS, MSYS, MinGW, NTLM, POSIX, Solaris, UNIX, Unix, Unicode,
WINE, WebDAV, Win32, winbind, WinIDN, Windows, Windows CE, Winsock.
Mostly OS names and a few more.
Also a couple of other minor text fixups.
Closes#14360
Based on the standards and guidelines we use for our documentation.
- expand contractions (they're => they are etc)
- host name = > hostname
- file name => filename
- user name = username
- man page => manpage
- run-time => runtime
- set-up => setup
- back-end => backend
- a HTTP => an HTTP
- Two spaces after a period => one space after period
Closes#14073
- clarify Curl_xfer_setup() with RECV/SEND flags and different calls for
which socket they operate on. Add a shutdown flag for secondary
sockets
- change Curl_xfer_setup() calls to new functions
- implement non-blocking connection shutdown at the end of receiving or
sending a transfer
Closes#13913
Building curl with -Wcomma, I see warnings about "possible misuse of
comma operator here" and moving fields assignment out of the for() fixes
it.
Closes#13392
new struct ip_quadruple for holding local/remote addr+port
- used in data->info and conn and cf-socket.c
- copy back and forth complete struct
- add 'secondary' to conn
- use secondary in reporting success for ftp 2nd connection
Reported-by: DasKutti on github
Fixes#13084Closes#13090
Curl_read/Curl_write clarifications
- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to 1clarify
when and at what level they operate
- send/recv of transfer related data is now done via
`Curl_xfer_send()/Curl_xfer_recv()` which no longer has
socket/socketindex as parameter. It decides on the transfer setup of
`conn->sockfd` and `conn->writesockfd` on which connection filter
chain to operate.
- send/recv on a specific connection filter chain is done via
`Curl_conn_send()/Curl_conn_recv()` which get the socket index as
parameter.
- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for naming
consistency
- clarify that the special CURLE_AGAIN handling to return `CURLE_OK`
with length 0 only applies to `Curl_xfer_send()` and CURLE_AGAIN is
returned by all other send() variants.
SingleRequest reshuffling
- move functions into request.[ch]
- differentiate between reset and free
- add Curl_req_done() to perform last actions
- add a send `bufq` to SingleRequest for future use in keeping upload data
Closes#12963
This clarifies the handling of server responses by folding the code for
the complicated protocols into their protocol handlers. This concerns
mainly HTTP and its bastard sibling RTSP.
The terms "read" and "write" are often used without clear context if
they refer to the connect or the client/application side of a
transfer. This PR uses "read/write" for operations on the client side
and "send/receive" for the connection, e.g. server side. If this is
considered useful, we can revisit renaming of further methods in another
PR.
Curl's protocol handler `readwrite()` method been changed:
```diff
- CURLcode (*readwrite)(struct Curl_easy *data, struct connectdata *conn,
- const char *buf, size_t blen,
- size_t *pconsumed, bool *readmore);
+ CURLcode (*write_resp)(struct Curl_easy *data, const char *buf, size_t blen,
+ bool is_eos, bool *done);
```
The name was changed to clarify that this writes reponse data to the
client side. The parameter changes are:
* `conn` removed as it always operates on `data->conn`
* `pconsumed` removed as the method needs to handle all data on success
* `readmore` removed as no longer necessary
* `is_eos` as indicator that this is the last call for the transfer
response (end-of-stream).
* `done` TRUE on return iff the transfer response is to be treated as
finished
This change affects many files only because of updated comments in
handlers that provide no implementation. The real change is that the
HTTP protocol handlers now provide an implementation.
The HTTP protocol handlers `write_resp()` implementation will get passed
**all** raw data of a server response for the transfer. The HTTP/1.x
formatted status and headers, as well as the undecoded response
body. `Curl_http_write_resp_hds()` is used internally to parse the
response headers and pass them on. This method is public as the RTSP
protocol handler also uses it.
HTTP/1.1 "chunked" transport encoding is now part of the general
*content encoding* writer stack, just like other encodings. A new flag
`CLIENTWRITE_EOS` was added for the last client write. This allows
writers to verify that they are in a valid end state. The chunked
decoder will check if it indeed has seen the last chunk.
The general response handling in `transfer.c:466` happens in function
`readwrite_data()`. This mainly operates now like:
```
static CURLcode readwrite_data(data, ...)
{
do {
Curl_xfer_recv_resp(data, buf)
...
Curl_xfer_write_resp(data, buf)
...
} while(interested);
...
}
```
All the response data handling is implemented in
`Curl_xfer_write_resp()`. It calls the protocol handler's `write_resp()`
implementation if available, or does the default behaviour.
All raw response data needs to pass through this function. Which also
means that anyone in possession of such data may call
`Curl_xfer_write_resp()`.
Closes#12480
https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html
as of 2023-11-29 [1].
Enable new recommended warnings (except `-Wsign-conversion`):
- enable `-Wformat=2` for clang (in both cmake and autotools).
- add `CURL_PRINTF()` internal attribute and mark functions accepting
printf arguments with it. This is a copy of existing
`CURL_TEMP_PRINTF()` but using `__printf__` to make it compatible
with redefinting the `printf` symbol:
https://gcc.gnu.org/onlinedocs/gcc-3.0.4/gcc_5.html#SEC94
- fix `CURL_PRINTF()` and existing `CURL_TEMP_PRINTF()` for
mingw-w64 and enable it on this platform.
- enable `-Wimplicit-fallthrough`.
- enable `-Wtrampolines`.
- add `-Wsign-conversion` commented with a FIXME.
- cmake: enable `-pedantic-errors` the way we do it with autotools.
Follow-up to d5c0351055#2747
- lib/curl_trc.h: use `CURL_FORMAT()`, this also fixes it to enable format
checks. Previously it was always disabled due to the internal `printf`
macro.
Fix them:
- fix bug where an `set_ipv6_v6only()` call was missed in builds with
`--disable-verbose` / `CURL_DISABLE_VERBOSE_STRINGS=ON`.
- add internal `FALLTHROUGH()` macro.
- replace obsolete fall-through comments with `FALLTHROUGH()`.
- fix fallthrough markups: Delete redundant ones (showing up as
warnings in most cases). Add missing ones. Fix indentation.
- silence `-Wformat-nonliteral` warnings with llvm/clang.
- fix one `-Wformat-nonliteral` warning.
- fix new `-Wformat` and `-Wformat-security` warnings.
- fix `CURL_FORMAT_SOCKET_T` value for mingw-w64. Also move its
definition to `lib/curl_setup.h` allowing use in `tests/server`.
- lib: fix two wrongly passed string arguments in log outputs.
Co-authored-by: Jay Satiro
- fix new `-Wformat` warnings on mingw-w64.
[1] 56c0fde389/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C%2B%2B.mdCloses#12489
This PR has these changes:
Renaming of unencode_* to cwriter, e.g. client writers
- documentation of sendf.h functions
- move max decode stack checks back to content_encoding.c
- define writer phase which was used as order before
- introduce phases for monitoring inbetween decode phases
- offering default implementations for init/write/close
Add type paramter to client writer's do_write()
- always pass all writes through the writer stack
- writers who only care about BODY data will pass other writes unchanged
add RAW and PROTOCOL client writers
- RAW used for Curl_debug() logging of CURLINFO_DATA_IN
- PROTOCOL used for updates to data->req.bytecount, max_filesize checks and
Curl_pgrsSetDownloadCounter()
- remove all updates of data->req.bytecount and calls to
Curl_pgrsSetDownloadCounter() and Curl_debug() from other code
- adjust test457 expected output to no longer see the excess write
Closes#12184
Previously it would only stop them from getting started if the size is
known to be too big then.
Update the libcurl and curl docs accordingly.
Fixes#11810
Reported-by: Elliot Killick
Assisted-by: Jay Satiro
Closes#11820
Aka "jumbo" or "amalgamation" builds. It means to compile all sources
per target as a single C source. This is experimental.
You can enable it by passing `-DCMAKE_UNITY_BUILD=ON` to cmake.
It requires CMake 3.16 or newer.
It makes builds (much) faster, allows for better optimizations and tends
to promote less ambiguous code.
Also add a new AppVeyor CI job and convert an existing one to use
"unity" mode (one MSVC, one MinGW), and enable it for one macOS CI job.
Fix related issues:
- add missing include guard to `easy_lock.h`.
- rename static variables and functions (and a macro) with names reused
across sources, or shadowed by local variables.
- add an `#undef` after use.
- add a missing `#undef` before use.
- move internal definitions from `ftp.h` to `ftp.c`.
- `curl_memory.h` fixes to make it work when included repeatedly.
- stop building/linking curlx bits twice for a static-mode curl tool.
These caused doubly defined symbols in unity builds.
- silence missing extern declarations compiler warning for ` _CRT_glob`.
- fix extern declarations for `tool_freq` and `tool_isVistaOrGreater`.
- fix colliding static symbols in debug mode: `debugtime()` and
`statename`.
- rename `ssl_backend_data` structure to unique names for each
TLS-backend, along with the `ssl_connect_data` struct member
referencing them. This required adding casts for each access.
- add workaround for missing `[P]UNICODE_STRING` types in certain Windows
builds when compiling `lib/ldap.c`. To support "unity" builds, we had
to enable `SCHANNEL_USE_BLACKLISTS` for Schannel (a Windows
`schannel.h` option) _globally_. This caused an indirect inclusion of
Windows `schannel.h` from `ldap.c` via `winldap.h` to have it enabled
as well. This requires `[P]UNICODE_STRING` types, which is apperantly
not defined automatically (as seen with both MSVS and mingw-w64).
This patch includes `<subauth.h>` to fix it.
Ref: https://github.com/curl/curl/runs/13987772013
Ref: https://dev.azure.com/daniel0244/curl/_build/results?buildId=15827&view=logs&jobId=2c9f582d-e278-56b6-4354-f38a4d851906&j=2c9f582d-e278-56b6-4354-f38a4d851906&t=90509b00-34fa-5a81-35d7-5ed9569d331c
- tweak unity builds to compile `lib/memdebug.c` separately in memory
trace builds to avoid PP confusion.
- force-disable unity for test programs.
- do not compile and link libcurl sources to libtests _twice_ when libcurl
is built in static mode.
KNOWN ISSUES:
- running tests with unity builds may fail in cases.
- some build configurations/env may not compile in unity mode. E.g.:
https://ci.appveyor.com/project/curlorg/curl/builds/47230972/job/51wfesgnfuauwl8q#L250
Ref: https://github.com/libssh2/libssh2/issues/1034
Ref: https://cmake.org/cmake/help/latest/prop_tgt/UNITY_BUILD.html
Ref: https://en.wikipedia.org/wiki/Unity_buildCloses#11095
If the previous line starts with if/while/for AND ends with a closed
parenthesis and there's an equal number of open and closed parentheses
on that line, verify that this line is indented $indent more steps, if
not a cpp line.
Also adjust the fall-out from this fix.
Closes#11054
Before this patch, enabling LDAPS required a manual C flag:
c1cfc31cfc/curl-cmake.sh (L105)
Fix this and enable LDAPS automatically when using `wldap32` (and
when not explicitly disabled). This matches autotools and `Makefile.mk`
behavior. Also remove issue from KNOWN_BUGS.
Add workaround for MSVS 2010 warning triggered by LDAPS now enabled
in more CI tests:
`ldap.c(360): warning C4306: 'type cast' : conversion from 'int' to 'void *' of greater size`
Ref: https://ci.appveyor.com/project/curlorg/curl/builds/46408284/job/v8mwl9yfbmoeqwlr#L312
Reported-by: JackBoosY on github
Reviewed-by: Jay Satiro
Reviewed-by: Marcel Raad
Fixes#6284Closes#10674
- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING
checksrc is updated to allow non-year using copyright statements
Closes#10205
