POSIX::tmpnam() broken for threaded 5.00503

[p5pRT]

Migrated from rt.perl.org#927 (status was 'resolved')

Searchable as RT927$

[p5pRT]

From hirschs@btv.ibm.com

Hello,

Perl 5.00503 has a problem in the POSIX library module when built
for threading, plus a small typo.

1) POSIX.xs looks for the definition of 'L_tmpname' in sys/types.h.
On AIX 4.1.5, Tru64 Unix 4.0D and Solaris (all I could check at the
moment), this is spelled 'L_tmpnam' (drop the trailing "e"). The Perl
function (mis)spelling should probably not change to preserve
operation of legacy code.

2) On non-threaded systems, tmpnam() can be called with an optional
pointer to storage for the generated string. If not provided, the
library returns a pointer to internal static storage. On threaded
systems, the parameter is no longer optional.

The existing XS stub for tmpnam() looks like it wants to be coded for
a single, optional parm that is defaulted to NULL​:

char *
tmpnam(s = 0)
  char * s = 0;

Unfortunately, the explicit assignment in the third line causes xsubpp
to omit generation of the necessary conditional expression. When NULL
is passed to tmpnam() under threaded Perl, the call simply fails.

The patch below takes care of both problems​:

Inline Patch

--- POSIX.xs.orig	Thu Mar  4 19:34:14 1999
+++ POSIX.xs	Mon Jun 28 13:42:46 1999
@@ -1520,8 +1520,8 @@
 		goto not_there;
 #endif
 	    if (strEQ(name, "L_tmpname"))
-#ifdef L_tmpname
-		return L_tmpname;
+#ifdef L_tmpnam
+		return L_tmpnam;
 #else
 		goto not_there;
 #endif
@@ -3367,9 +3367,17 @@
 	char *		buffer
 	size_t		nbytes
 
-char *
-tmpnam(s = 0)
-	char *		s = 0;
+SV *
+tmpnam()
+    PREINIT:
+	U32 i;
+	int len;
+    CODE:
+	RETVAL = newSVpv("", L_tmpnam);
+	len = strlen(tmpnam(SvPV(RETVAL, i)));
+	SvCUR_set(RETVAL, len);
+    OUTPUT:
+	RETVAL
 
 void
 abort()

My solution instantiates an SV with a blank string of requisite length preallocated\, then calls tmpnam\(\) with a pointer to this string\. The return value is checked for its new \(potentially shorter\) length\, and the SV adjusted to reflect this\. Unless I'm misreading the perlguts doc\, Perl manages all storage\. No memory leaks should result\.

Since the motivation for passing a parameter to tempnam() under C
relates to storage allocation, I made no attempt to support this
feature under Perl.

Here is the test program I used to verify the fix​:

#!/usr/local/bin/perl5.00503 -w

use strict;

use POSIX qw(​:stdio_h);

my $tmpfile = POSIX​::tmpnam();
$tmpfile or die "$!";
print "tempfile = $tmpfile\n";

my $len = L_tmpname;
print "L_tmpname = $len\n";

Please contact me if any more information is required?

Regards,

Steven N. Hirsch

Development Engineer
IBM Microelectronics

Perl Info

Site configuration information for perl 5.00503:

Configured by hirschs at Thu Apr 15 16:28:17 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=aix, osvers=4.1.5.0, archname=aix-thread
    uname='aix stargate 1 4 000092735700 '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define useperlio=undef d_sfio=undef
  Compiler:
    cc='cc_r', optimize='-O', gccversion=
    cppflags=''
    ccflags ='-D_ALL_SOURCE -D_ANSI_C_SOURCE -D_POSIX_SOURCE -qmaxmem=8192 -DNEED_PTHREAD_INIT -I/usr/local/include'
    stdchar='unsigned char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=8
    alignbytes=8, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='ld', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /usr/ccs/lib
    libs=-ldbm -ldb -ldl -lld -lm -lc_r -lc -lbsd -lPW
    libc=, so=a, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_aix.xs, dlext=so, d_dlsymun=undef, ccdlflags='-bE:perl.exp'
    cccdlflags=' ', lddlflags='-bhalt:4 -bM:SRE -bI:$(PERL_INC)/perl.exp -bE:$(BASEEXT).exp -b noentry -lpthreads -lc_r -lc -L/usr/local/lib'

Locally applied patches:
    


@INC for perl 5.00503:
    /usr/local/lib/perl5/5.005/aix-thread
    /usr/local/lib/perl5/5.005
    /usr/local/lib/perl5/site_perl/5.005/aix-thread
    /usr/local/lib/perl5/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/afs/btv.ibm.com/u4/hirschs
    LANG=en_US
    LANGUAGE (unset)
    LC__FASTMSG=true
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/prod/local/bin:.:/usr/local/bin:/usr/bin:/etc:/usr/sbin:/usr/ucb:/usr/bin/X11:/sbin:/usr/afsws/bin:/usr/afsws/etc:/usr/prod/local/bin:/usr/prod/contrib/bin:/usr/prod/tools/bin:/afs/btv.ibm.com/data/a29tools/cadence/bin:/afs/btv.ibm.com/data/a29tools/cadence/cds434/9502/tools/bin:/afs/btv.ibm.com/data/a29tools/cadence/cds434/9502/tools/dfII/bin:/afs/btv/data/a29v/work/bin:/afs/btv.ibm.com/data/a29tools/iss/prod/code:
    PERL_BADLANG (unset)
    SHELL=/bin/ksh