# 5.NEXT Integer and String type modifications - Thread: https://externals.io/message/67596 - Original archive: https://news-web.php.net/php.internals/67596 - Started by Anthony Ferrara on 2013-05-31T19:11:34+00:00 - Messages: 19 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #67596 — Anthony Ferrara — 2013-05-31T19:11:34+00:00 URL: https://externals.io/message/67596#67596 Hello all, I want to start an idea thread (or at least get a conversation going) about cleaning up the core integer data type and string lengths. Here's my ideas: 1. Change string length in the ZVAL from int to size_t - http://lxr.php.net/xref/PHP_5_5/Zend/zend.h#321 2. Change long in the ZVAL (lval) to a system-determined 64bit fixed size There are two reasons for this. First, on VS compiles (windows), the current long size is always 32 bit. So that means even 64 bit compiles may or may not have 64 bit ints. The second reason is that right now PHP can't really handle strings >= 2^31 characters even on 64 bit compiles. The problem gets pretty comical: $ php -d memory_limit=499g -r "\$string = str_repeat('x',pow(2, 32)) . str_repeat('x', pow(2,4)); var_dump(strlen(\$string));" int(16) Obviously there's a pretty significant ABI break here. I propose a "tweak" of the Z_* macros to "fix" that. Basically, Z_STRLEN() will cast the result to an int. This is the same behavior as today, and will mean that existing extensions continue to function exactly as today. But new extensions (and elsewhere in core) can use a new macro Z_STRSIZE() which will return the native size_t. Likewise we can do the same for the long data type (Z_LVAL() returns a long, and Z_PHPLVAL() returns a php_long (which is a typedef of a 64 bit compiler specific type). It'll also require 2 new zend_parse_parameters types (one for php_long and one for the string len using size_t instead)... Additionally, I'd propose a set of central helpers to cast back and forth between php_long and long, as well as int to size_t (with overflow checks, allowing us to do errors on detected overflows instead of silently ignoring them as today). It would be a *gigantic* patch, but the userland effects should be minimal (the only changes would be supporting longer strings, and consistent 64 bit int support). The performance considerations should be minimal for non-legacy code (as both would still be using native data types)... What do you think? What am I missing from this? Or is this just a horrific idea (given the current implementation details)...? Anthony --- ## #67597 — Derick Rethans — 2013-05-31T19:33:17+00:00 URL: https://externals.io/message/67596#67597 · In reply to: #67596 Anthony Ferrara wrote: > I want to start an idea thread (or at least get a conversation going) > about > cleaning up the core integer data type and string lengths. Here's my > ideas: > > 1. Change string length in the ZVAL from int to size_t > - http://lxr.php.net/xref/PHP_5_5/Zend/zend.h#321 > 2. Change long in the ZVAL (lval) to a system-determined 64bit fixed > size In principle I think this is great thing to do. Not having a 64 bit type is annoying. I'm a bit curious on how this is going to work with all sorts of object wrappers that are now in place as workaround. And casting int64 to int32 needs to very well looked at as well. Derick --- ## #67598 — Anthony Ferrara — 2013-05-31T20:03:34+00:00 URL: https://externals.io/message/67596#67598 · In reply to: #67597 Derick, In principle I think this is great thing to do. Not having a 64 bit type is > annoying. I'm a bit curious on how this is going to work with all sorts of > object wrappers that are now in place as workaround. And casting int64 to > int32 needs to very well looked at as well. > > As far as the casting, my first reaction would be to raise an E_ENGINE_NOTICE on data loss (casting from int64 to int32 with ints > 32 bit) and then adjusting the value to the nearest representable value (LONG_MAX or LONG_MIN). In other words, it may need to be more than a simple cast (an inline function perhaps)... As far as object wrappers, any particular examples that you're thinking of? Thanks for the thoughts Anthony --- ## #67599 — Derick Rethans — 2013-05-31T20:21:35+00:00 URL: https://externals.io/message/67596#67599 · In reply to: #67598 Anthony Ferrara wrote: > Derick, > > In principle I think this is great thing to do. Not having a 64 bit > type is > > […] > sorts of > > […] > int64 to > > […] > As far as the casting, my first reaction would be to raise an > E_ENGINE_NOTICE on data loss (casting from int64 to int32 with ints > > 32 > bit) and then adjusting the value to the nearest representable value > (LONG_MAX or LONG_MIN). In other words, it may need to be more than a > simple cast (an inline function perhaps) That can't be handled in applications though ... > As far as object wrappers, any particular examples that you're > thinking of? It happens on atleast two extensions that I've written, dbus and mongodb, so I was thinking there must be a few more. Cheers, Derick --- ## #67600 — Sherif Ramadan — 2013-05-31T20:48:19+00:00 URL: https://externals.io/message/67596#67600 · In reply to: #67599 > Anthony Ferrara wrote: > > > […] > > That can't be handled in applications though ... > > > […] > > It happens on atleast two extensions that I've written, dbus and mongodb, > so I was thinking there must be a few more. > > PDO does a lot of that in various places. > Cheers, > Derick --- ## #67601 — Andrey Hristov — 2013-06-01T09:53:42+00:00 URL: https://externals.io/message/67596#67601 · In reply to: #67598 Hi, > Derick, > > > In principle I think this is great thing to do. Not having a 64 bit type is > > […] > As far as the casting, my first reaction would be to raise an > E_ENGINE_NOTICE on data loss (casting from int64 to int32 with ints > 32 > bit) and then adjusting the value to the nearest representable value > (LONG_MAX or LONG_MIN). In other words, it may need to be more than a > simple cast (an inline function perhaps)... > > As far as object wrappers, any particular examples that you're thinking of? > > Thanks for the thoughts > > Anthony > what about new type IS_LONG64, new field in union and new set of macros for this type. New extensions or rewritten extensions will use the new macros. In 2-3 major versions, 5.8 for example, old macros will be dropped. Enough time extensions to be ported to the new macros. Best, Andrey --- ## #67602 — Pierre Joye — 2013-06-02T06:34:00+00:00 URL: https://externals.io/message/67596#67602 · In reply to: #67596 > Hello all, > > I want to start an idea thread (or at least get a conversation going) about > cleaning up the core integer data type and string lengths. Here's my ideas: > > 1. Change string length in the ZVAL from int to size_t > - http://lxr.php.net/xref/PHP_5_5/Zend/zend.h#321 Huge +1, as well as for any (allocated) random buffer we use/allocate. > 2. Change long in the ZVAL (lval) to a system-determined 64bit fixed size > > There are two reasons for this. First, on VS compiles (windows), the > current long size is always 32 bit. So that means even 64 bit compiles may > or may not have 64 bit ints. To do it as transparently as possible and a one time change (but we can't avoid #ifdef) is to add a php_int type, or, my prefered solution, we go with int64_t for the zval int type. One open question is whether we keep the architecture dependent integer size, which is rather annoying. > The second reason is that right now PHP can't really handle strings >= 2^31 > characters even on 64 bit compiles. The problem gets pretty comical: > > $ php -d memory_limit=499g -r "\$string = str_repeat('x',pow(2, 32)) . > str_repeat('x', pow(2,4)); var_dump(strlen(\$string));" > int(16) > > Obviously there's a pretty significant ABI break here. I propose a "tweak" > of the Z_* macros to "fix" that. Basically, Z_STRLEN() will cast the result > to an int. This is the same behavior as today, and will mean that existing > extensions continue to function exactly as today. But new extensions (and > elsewhere in core) can use a new macro Z_STRSIZE() which will return the > native size_t. A new macro will be a good solution, but I would name it what it actually is, Z_SIZE_T. > Likewise we can do the same for the long data type (Z_LVAL() returns a > long, and Z_PHPLVAL() returns a php_long (which is a typedef of a 64 bit > compiler specific type). I'm not a fan of adding a php_long type but move to the int*_t types. or php_int*_t types for easy understanding of what is actually used. > It'll also require 2 new zend_parse_parameters types (one for php_long and > one for the string len using size_t instead)... > Additionally, I'd propose a set of central helpers to cast back and forth > between php_long and long, as well as int to size_t (with overflow checks, > allowing us to do errors on detected overflows instead of silently ignoring > them as today). Same as before, stop using long which has been proven to be not really portable and can be confusing. > It would be a *gigantic* patch, but the userland effects should be minimal > (the only changes would be supporting longer strings, and consistent 64 bit > int support). The performance considerations should be minimal for > non-legacy code (as both would still be using native data types)... > > What do you think? What am I missing from this? Or is this just a horrific > idea (given the current implementation details)...? It is a very good idea and we have been discussed it many times, since too long. I'm not sure it can be done in 5.x tho'. But no matter when it will be done, we can already begin to do it in a fork and write down a RFC. I'll be very happy to help here, on my todos for full win64 support. Also we will need to patch libraries as well to avoid the same issues to happen there. A first discussion I had with many of the developers working on these libraries show that they have (almost) no issue to clean up this as well. Cheers, -- Pierre @pierrejoye | http://www.libgd.org --- ## #67603 — johannes@schlueters.de — 2013-06-02T06:40:08+00:00 URL: https://externals.io/message/67596#67603 · In reply to: #67601 Andrey Hristov wrote: >what about new type IS_LONG64, new field in union and new set of macros > >for this type. New extensions or rewritten extensions will use the new >macros. In 2-3 major versions, 5.8 for example, old macros will be >dropped. Enough time extensions to be ported to the new macros. Unortunately a lot of code makes assumptions about the type system, so adding (or changing) a type can cause issues which are hard to find without going through the code line by line with a lot of concentration, mistakes there will lead to evil bugs ... and all that where the cmpiler won't help unless we change names of structure elements and macros ... so forcing us to touch any line using a zval bool/long/... But if people are volunteering I'd be happy about such improvements. johannes --- ## #67604 — johannes@schlueters.de — 2013-06-02T06:52:29+00:00 URL: https://externals.io/message/67596#67604 · In reply to: #67596 Anthony Ferrara wrote: >1. Change string length in the ZVAL from int to size_t > - http://lxr.php.net/xref/PHP_5_5/Zend/zend.h#321 This would be good but a lot of work and an hard to track engine change ... >2. Change long in the ZVAL (lval) to a system-determined 64bit fixed >size Didn't somebody do a great chunk of the work to add arbitrary integer support? 64bit is nice, arbitrary would be nicer (and both have issues in situations where we pass the PHP int to an external library expecting an int or long or such ...) >Obviously there's a pretty significant ABI break here. I propose a >"tweak" of the Z_* macros to "fix" that. Basically, Z_STRLEN() will cast the >result to an int. This is the same behavior as today, and will mean that >existing extensions continue to function exactly as today. But new extensions >(and elsewhere in core) can use a new macro Z_STRSIZE() which will return >the native size_t. This will give strange results and potential bugs with strings on systems where MAX_SIZE_T > MAXINT when a user passes a string longer than MAXINT (luckily this, on all relevnt systems) means more than 2GB data, which usully should be hard to do for an external attacker and be prevented by memory_limit etc. >It would be a *gigantic* patch, but the userland effects should be >minimal (the only changes would be supporting longer strings, and consistent 64 >bit int support). The performance considerations should be minimal for >non-legacy code (as both would still be using native data types)... History shows that such gigantic patches are often not finished and done as people underestimate the size of PHP and the fact that all etensions have to be checked which for this case means checking each external lib for their correct type for all their functions etc ... but I don't wan to stop you, I'm happy if you do this :-) (while I'm also happy about everybody spending time on fixing bugs instead of adding such high-risk changes ;-)) johannes --- ## #67606 — johannes@schlueters.de — 2013-06-02T09:11:58+00:00 URL: https://externals.io/message/67596#67606 · In reply to: #67602 > > […] > > A new macro will be a good solution, but I would name it what it > actually is, Z_SIZE_T. That's not what it is. It is the length of the string aka. var.value.str.length as such it should indicate its relation to a string. So something like Z_STRSIZE is correct (and the name is nice thinking about Unicode strings where length (characters) != size (bytes)) johannes --- ## #67607 — Pierre Joye — 2013-06-02T11:07:43+00:00 URL: https://externals.io/message/67596#67607 · In reply to: #67606 On Sun, Jun 2, 2013 at 11:11 AM, Johannes Schlüter wrote: > > > > > > […] > > That's not what it is. It is the length of the string aka. var.value.str.length as such it should indicate its relation to a string. So something like Z_STRSIZE is correct (and the name is nice thinking about Unicode strings where length (characters) != size (bytes)) It is size_t. There is no such thing as unicode or multibyte string length in php but in mbstring, intl or iconv, to name a few. php strings are buffers, and buffers lengths use size_t. This macro (and other) are about extension developers, working in C, not about what its representation in userland. Even if they are closely related, obviously. The day we will have actual multi bytes/unicode strings, we will need a separate length to represent in characters (be multi bytes). Cheers, -- Pierre @pierrejoye | http://www.libgd.org --- ## #67620 — Michael Wallner — 2013-06-04T04:59:22+00:00 URL: https://externals.io/message/67596#67620 · In reply to: #67606 > > > > > > […] > > That's not what it is. It is the length of the string aka. var.value.str.length as such it should indicate its relation to a string. So something like Z_STRSIZE is correct (and the name is nice thinking about Unicode strings where length (characters) != size (bytes)) +1 for the idea +1 for Z_STRSIZE +1 for volunteering, as far as time permits! -- Regards, Mike --- ## #67621 — Pierre Joye — 2013-06-04T06:33:12+00:00 URL: https://externals.io/message/67596#67621 · In reply to: #67620 > +1 for the idea > +1 for Z_STRSIZE at least Z_STRSIZET for the reason explained earlier :) -- Pierre @pierrejoye | http://www.libgd.org --- ## #67622 — Julien Pauli — 2013-06-04T07:47:18+00:00 URL: https://externals.io/message/67596#67622 · In reply to: #67621 +1 , that will make a big diff . I'm here to help others to go forward. Julien.P > > > > […] > > at least Z_STRSIZET for the reason explained earlier :) > > > -- > Pierre > > @pierrejoye | http://www.libgd.org --- ## #67623 — Ivan Enderlin @ Hoa — 2013-06-04T08:41:19+00:00 URL: https://externals.io/message/67596#67623 · In reply to: #67604 Hey :-), > > […] > History shows that such gigantic patches are often not finished and done as people underestimate the size of PHP and the fact that all etensions have to be checked which for this case means checking each external lib for their correct type for all their functions etc ... but I don't wan to stop you, I'm happy if you do this :-) (while I'm also happy about everybody spending time on fixing bugs instead of adding such high-risk changes ;-)) Is it possible to use a static C analyzer here? It could help a lot. I think about Frama-C [1], Pork [2] (now included in Oink [3]) or Clang Static Analyser [4] to name a few. A more complete list can be found in [5]. The idea is excellent by the way :-). Cheers. [1] http://frama-c.com/ [2] https://developer.mozilla.org/en/docs/Pork [3] http://daniel-wilkerson.appspot.com/oink/index.html [4] http://clang-analyzer.llvm.org/ [5] http://en.wikipedia.org/wiki/List_of_tools_for_static_code_analysis#C.2FC.2B.2B -- Ivan Enderlin Developer of Hoa http://hoa-project.net/ PhD. student at DISC/Femto-ST (Vesontio) and INRIA (Cassis) http://disc.univ-fcomte.fr/ and http://www.inria.fr/ Member of HTML and WebApps Working Group of W3C http://w3.org/ --- ## #67624 — johannes@schlueters.de — 2013-06-04T10:01:21+00:00 URL: https://externals.io/message/67596#67624 · In reply to: #67623 > > […] > Is it possible to use a static C analyzer here? It could help a lot. I > think about Frama-C [1], Pork [2] (now included in Oink [3]) or Clang > Static Analyser [4] to name a few. A more complete list can be found > in [5]. To some degree, but there are enough cases which are technically and such correct but logically wrong, so the code still has to be reviewed. johannes --- ## #67625 — Pierre Joye — 2013-06-04T10:08:09+00:00 URL: https://externals.io/message/67596#67625 · In reply to: #67623 On Tue, Jun 4, 2013 at 10:41 AM, Ivan Enderlin @ Hoa wrote: > Hey :-), > > > > > […] > > Is it possible to use a static C analyzer here? It could help a lot. I think > about Frama-C [1], Pork [2] (now included in Oink [3]) or Clang Static > Analyser [4] to name a few. A more complete list can be found in [5]. We do it using Visual C++ static analyzer, which is an excellent tool for this kind of issue, almost on all commits. As soon as we have a fork for these changes I will add it so we can get regular updates. -- Pierre @pierrejoye | http://www.libgd.org --- ## #67628 — Ivan Enderlin @ Hoa — 2013-06-04T13:24:55+00:00 URL: https://externals.io/message/67596#67628 · In reply to: #67625 > On Tue, Jun 4, 2013 at 10:41 AM, Ivan Enderlin @ Hoa > wrote: > > […] > We do it using Visual C++ static analyzer, which is an excellent tool > for this kind of issue, almost on all commits. As soon as we have a > fork for these changes I will add it so we can get regular updates. Excellent! -- Ivan Enderlin Developer of Hoa http://hoa-project.net/ PhD. student at DISC/Femto-ST (Vesontio) and INRIA (Cassis) http://disc.univ-fcomte.fr/ and http://www.inria.fr/ Member of HTML and WebApps Working Group of W3C http://w3.org/ --- ## #69310 — Martin Keckeis — 2013-09-24T08:00:11+00:00 URL: https://externals.io/message/67596#69310 · In reply to: #67628 2013/6/4 Ivan Enderlin @ Hoa > > > > > […] > Excellent! Since Anthony is sadly gone, is there still something going on in this direction? Just fallen into a bug related to this with future DateTimes.... after 2038-01-19 03:14:07