diff options
| -rw-r--r-- | INSTALL | 8 | ||||
| -rw-r--r-- | pod/perldiag.pod | 8 | ||||
| -rw-r--r-- | pod/perlthrtut.pod | 13 | ||||
| -rw-r--r-- | reentr.c | 61 | ||||
| -rw-r--r-- | reentr.pl | 61 |
5 files changed, 131 insertions, 20 deletions
@@ -712,6 +712,14 @@ If you decide to use ithreads, the 'threads' module allows their use, and the 'Thread' module offers an interface to both 5005threads and ithreads (whichever has been configured). +When building threaded for certain library calls like the getgr*() and +the getpw*() there is a dynamically sized result buffer: the buffer +starts small but Perl will keep growing the buffer until the result fits. +To get a fixed upper limit you will have to recompile Perl with +PERL_REENTRANT_MAXSIZE defined to be the number of bytes you want. +One way to do this is to run Configure with +C<-Accflags=-DPERL_REENTRANT_MAXSIZE=65536> + =head2 Large file support. Since Perl 5.6.0, Perl has supported large files (files larger than diff --git a/pod/perldiag.pod b/pod/perldiag.pod index 3da728d06a..40f9929156 100644 --- a/pod/perldiag.pod +++ b/pod/perldiag.pod @@ -3118,6 +3118,14 @@ signed integers. See L<perlfunc/pack>. (F) You can't specify a repeat count so large that it overflows your signed integers. See L<perlfunc/unpack>. +=item Result from %s larger than %d bytes + +(W misc) A library call like getgrent() tried to return more results +than Perl was willing to accept. This happens only when Perl has been +compiled to have threads and to have an upper limit on such calls +(the default is to keep regrowing the result buffer until the result fits). +However, now the results were truncated. + =item Reversed %s= operator (W syntax) You wrote your assignment operator backwards. The = must diff --git a/pod/perlthrtut.pod b/pod/perlthrtut.pod index cafcbb21a6..575ec27c52 100644 --- a/pod/perlthrtut.pod +++ b/pod/perlthrtut.pod @@ -1016,10 +1016,15 @@ calls, they will be used. Beyond that, Perl is at the mercy of the thread-safety or -unsafety of the calls. Please consult your C library call documentation. -In some platforms the thread-safe interfaces may fail if the result -buffer is too small (for example getgrent() may return quite large -group member lists). Perl will retry growing the result buffer -a few times, but only up to 64k (for safety reasons). +On some platforms the thread-safe library interfaces may fail if the +result buffer is too small (for example the user group databases may +be rather large, and the reentrant interfaces may have to carry around +a full snapshot of those databases). Perl will start with a small +buffer, but keep retrying and growing the result buffer +until the result fits. If this limitless growing sounds bad for +security or memory consumption reasons you can recompile Perl with +PERL_REENTRANT_MAXSIZE defined to the maximum number of bytes you will +allow. =head1 Conclusion @@ -312,19 +312,24 @@ Perl_reentrant_retry(const char *f, ...) # if defined(USE_HOSTENT_BUFFER) || defined(USE_NETENT_BUFFER) || defined(USE_PROTOENT_BUFFER) || defined(USE_SERVENT_BUFFER) int anint; # endif +#ifdef PERL_REENTRANT_MAXSIZE + static const char larger[] = "Result from %s larger than %d bytes"; +#endif va_list ap; va_start(ap, f); -#define REENTRANTHALFMAXSIZE 32768 /* The maximum may end up twice this. */ - switch (PL_op->op_type) { #ifdef USE_HOSTENT_BUFFER case OP_GHBYADDR: case OP_GHBYNAME: case OP_GHOSTENT: { - if (PL_reentrant_buffer->_hostent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_hostent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_hostent_size *= 2; Renew(PL_reentrant_buffer->_hostent_buffer, PL_reentrant_buffer->_hostent_size, char); @@ -351,7 +356,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GGRGID: case OP_GGRENT: { - if (PL_reentrant_buffer->_grent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_grent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Gid_t gid; PL_reentrant_buffer->_grent_size *= 2; Renew(PL_reentrant_buffer->_grent_buffer, @@ -377,7 +386,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GNBYNAME: case OP_GNETENT: { - if (PL_reentrant_buffer->_netent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_netent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Netdb_net_t net; PL_reentrant_buffer->_netent_size *= 2; Renew(PL_reentrant_buffer->_netent_buffer, @@ -396,6 +409,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -404,7 +422,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GPWUID: case OP_GPWENT: { - if (PL_reentrant_buffer->_pwent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_pwent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Uid_t uid; PL_reentrant_buffer->_pwent_size *= 2; Renew(PL_reentrant_buffer->_pwent_buffer, @@ -422,6 +444,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -430,7 +457,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GPBYNUMBER: case OP_GPROTOENT: { - if (PL_reentrant_buffer->_protoent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_protoent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_protoent_size *= 2; Renew(PL_reentrant_buffer->_protoent_buffer, PL_reentrant_buffer->_protoent_size, char); @@ -447,6 +478,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -455,7 +491,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GSBYPORT: case OP_GSERVENT: { - if (PL_reentrant_buffer->_servent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_servent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_servent_size *= 2; Renew(PL_reentrant_buffer->_servent_buffer, PL_reentrant_buffer->_servent_size, char); @@ -474,6 +514,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -784,19 +784,24 @@ Perl_reentrant_retry(const char *f, ...) # if defined(USE_HOSTENT_BUFFER) || defined(USE_NETENT_BUFFER) || defined(USE_PROTOENT_BUFFER) || defined(USE_SERVENT_BUFFER) int anint; # endif +#ifdef PERL_REENTRANT_MAXSIZE + static const char larger[] = "Result from %s larger than %d bytes"; +#endif va_list ap; va_start(ap, f); -#define REENTRANTHALFMAXSIZE 32768 /* The maximum may end up twice this. */ - switch (PL_op->op_type) { #ifdef USE_HOSTENT_BUFFER case OP_GHBYADDR: case OP_GHBYNAME: case OP_GHOSTENT: { - if (PL_reentrant_buffer->_hostent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_hostent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_hostent_size *= 2; Renew(PL_reentrant_buffer->_hostent_buffer, PL_reentrant_buffer->_hostent_size, char); @@ -823,7 +828,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GGRGID: case OP_GGRENT: { - if (PL_reentrant_buffer->_grent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_grent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Gid_t gid; PL_reentrant_buffer->_grent_size *= 2; Renew(PL_reentrant_buffer->_grent_buffer, @@ -849,7 +858,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GNBYNAME: case OP_GNETENT: { - if (PL_reentrant_buffer->_netent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_netent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Netdb_net_t net; PL_reentrant_buffer->_netent_size *= 2; Renew(PL_reentrant_buffer->_netent_buffer, @@ -868,6 +881,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -876,7 +894,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GPWUID: case OP_GPWENT: { - if (PL_reentrant_buffer->_pwent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_pwent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { Uid_t uid; PL_reentrant_buffer->_pwent_size *= 2; Renew(PL_reentrant_buffer->_pwent_buffer, @@ -894,6 +916,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -902,7 +929,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GPBYNUMBER: case OP_GPROTOENT: { - if (PL_reentrant_buffer->_protoent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_protoent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_protoent_size *= 2; Renew(PL_reentrant_buffer->_protoent_buffer, PL_reentrant_buffer->_protoent_size, char); @@ -919,6 +950,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif @@ -927,7 +963,11 @@ Perl_reentrant_retry(const char *f, ...) case OP_GSBYPORT: case OP_GSERVENT: { - if (PL_reentrant_buffer->_servent_size <= REENTRANTHALFMAXSIZE) { +#ifdef PERL_REENTRANT_MAXSIZE + if (PL_reentrant_buffer->_servent_size <= + PERL_REENTRANT_MAXSIZE / 2) +#endif + { PL_reentrant_buffer->_servent_size *= 2; Renew(PL_reentrant_buffer->_servent_buffer, PL_reentrant_buffer->_servent_size, char); @@ -946,6 +986,11 @@ Perl_reentrant_retry(const char *f, ...) break; } } +#ifdef PERL_REENTRANT_MAXSIZE + else if (ckWARN(WARN_MISC)) + Perl_warner(aTHX_ packWARN(WARN_MISC), + larger, OP_NAME(PL_op), PERL_REENTRANT_MAXSIZE); +#endif } break; #endif |