251047 |
28-May-2013 |
kib |
The getcontext() from the __fillcontextx() call in the check_deferred_signal() returns twice, since handle_signal() emulates the return from the normal signal handler by sigreturn(2)ing the passed context. Second return is performed on the destroyed stack frame, because __fillcontextx() has already returned. This causes undefined and bad behaviour, usually the victim thread gets SIGSEGV.
Avoid nested frame and the need to return from it by doing direct call to getcontext() in the check_deferred_signal() and using a new private libc helper __fillcontextx2() to complement the context with the extended CPU state if the deferred signal is still present.
The __fillcontextx() is now unused, but is kept to allow older libthr.so to be used with the new libc.
Mark __fillcontextx() as returning twice [1].
Reported by: pgj Pointy hat to: kib Discussed with: dim Tested by: pgj, dim Suggested by: jilles [1] MFC after: 1 week
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143658 |
15-Mar-2005 |
das |
Remove fpsetsticky(). This was added for SysV compatibility, but due to mistakes from day 1, it has always had semantics inconsistent with SVR4 and its successors. In particular, given argument M:
- On Solaris and FreeBSD/{alpha,sparc64}, it clobbers the old flags and *sets* the new flag word to M. (NetBSD, too?) - On FreeBSD/{amd64,i386}, it *clears* the flags that are specified in M and leaves the remaining flags unchanged (modulo a small bug on amd64.) - On FreeBSD/ia64, it is not implemented.
There is no way to fix fpsetsticky() to DTRT for both old FreeBSD apps and apps ported from other operating systems, so the best approach seems to be to kill the function and fix any apps that break. I couldn't find any ports that use it, and any such ports would already be broken on FreeBSD/ia64 and Linux anyway.
By the way, the routine has always been undocumented in FreeBSD, except for an MLINK to a manpage that doesn't describe it. This manpage has stated since 5.3-RELEASE that the functions it describes are deprecated, so that must mean that functions that it is *supposed* to describe but doesn't are even *more* deprecated. ;-)
Note that fpresetsticky() has been retained on FreeBSD/i386. As far as I can tell, no other operating systems or ports of FreeBSD implement it, so there's nothing for it to be inconsistent with.
PR: 75862 Suggested by: bde
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140607 |
22-Jan-2005 |
das |
Replace the ldexp() implementation in libc with a renamed copy of the scalbn() implementation from libm. (The two functions are defined to be identical, but ldexp() lives in libc for backwards compatibility.) The old ldexp() implementation... - was more complicated than this one - set errno instead of raising FP exceptions - got some corner cases wrong (e.g. ldexp(1.0, 2000) in round-to-zero mode)
The new implementation lives in libc/gen instead of libc/$MACHINE_ARCH/gen, since we don't need N copies of a machine-independent file. The amd64 and i386 platforms retain their fast and correct MD implementations and override this one.
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131852 |
09-Jul-2004 |
das |
Implement the classification macros isfinite(), isinf(), isnan(), and isnormal() the hard way, rather than relying on fpclassify(). This is a lose in the sense that we need a total of 12 functions, but it is necessary for binary compatibility because we have never bumped libm's major version number. In particular, isinf(), isnan(), and isnanf() were BSD libc functions before they were C99 macros, so we can't reimplement them in terms of fpclassify() without adding a dependency on libc.so.5. I have tried to arrange things so that programs that could be compiled in FreeBSD 4.X will generate the same external references when compiled in 5.X. At the same time, the new macros should remain C99-compliant.
The isinf() and isnan() functions remain in libc for historical reasons; however, I have moved the functions that implement the macros isfinite() and isnormal() to libm where they belong. Moreover, half a dozen MD versions of isinf() and isnan() have been replaced with MI versions that work equally well.
Prodded by: kris
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110769 |
12-Feb-2003 |
mike |
o Implement C99 classification macros isfinite(), isinf(), isnan(), isnormal(). The current isinf() and isnan() are perserved for binary compatibility with 5.0, but new programs will use the macros. o Implement C99 comparison macros isgreater(), isgreaterequal(), isless(), islessequal(), islessgreater(), isunordered().
Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
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110566 |
08-Feb-2003 |
mike |
Implement fpclassify(): o Add a MD header private to libc called _fpmath.h; this header contains bitfield layouts of MD floating-point types. o Add a MI header private to libc called fpmath.h; this header contains bitfield layouts of MI floating-point types. o Add private libc variables to lib/libc/$arch/gen/infinity.c for storing NaN values. o Add __double_t and __float_t to <machine/_types.h>, and provide double_t and float_t typedefs in <math.h>. o Add some C99 manifest constants (FP_ILOGB0, FP_ILOGBNAN, HUGE_VALF, HUGE_VALL, INFINITY, NAN, and return values for fpclassify()) to <math.h> and others (FLT_EVAL_METHOD, DECIMAL_DIG) to <float.h> via <machine/float.h>. o Add C99 macro fpclassify() which calls __fpclassify{d,f,l}() based on the size of its argument. __fpclassifyl() is never called on alpha because (sizeof(long double) == sizeof(double)), which is good since __fpclassifyl() can't deal with such a small `long double'.
This was developed by David Schultz and myself with input from bde and fenner.
PR: 23103 Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU> (significant portions) Reviewed by: bde, fenner (earlier versions)
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