correct error signalling for opendir() failure
[openssl.git] / crypto / err / err.c
1 /* crypto/err/err.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  * 
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  * 
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  * 
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from 
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  * 
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  * 
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58
59 #include <stdio.h>
60 #include <stdarg.h>
61 #include <openssl/lhash.h>
62 #include <openssl/crypto.h>
63 #include "cryptlib.h"
64 #include <openssl/buffer.h>
65 #include <openssl/err.h>
66 #include <openssl/crypto.h>
67
68
69 static LHASH *error_hash=NULL;
70 static LHASH *thread_hash=NULL;
71
72 static unsigned long err_hash(ERR_STRING_DATA *a);
73 static int err_cmp(ERR_STRING_DATA *a, ERR_STRING_DATA *b);
74 static unsigned long pid_hash(ERR_STATE *pid);
75 static int pid_cmp(ERR_STATE *a,ERR_STATE *pid);
76 static unsigned long get_error_values(int inc,const char **file,int *line,
77                                       const char **data,int *flags);
78 static void ERR_STATE_free(ERR_STATE *s);
79 #ifndef NO_ERR
80 static ERR_STRING_DATA ERR_str_libraries[]=
81         {
82 {ERR_PACK(ERR_LIB_NONE,0,0)             ,"unknown library"},
83 {ERR_PACK(ERR_LIB_SYS,0,0)              ,"system library"},
84 {ERR_PACK(ERR_LIB_BN,0,0)               ,"bignum routines"},
85 {ERR_PACK(ERR_LIB_RSA,0,0)              ,"rsa routines"},
86 {ERR_PACK(ERR_LIB_DH,0,0)               ,"Diffie-Hellman routines"},
87 {ERR_PACK(ERR_LIB_EVP,0,0)              ,"digital envelope routines"},
88 {ERR_PACK(ERR_LIB_BUF,0,0)              ,"memory buffer routines"},
89 {ERR_PACK(ERR_LIB_BIO,0,0)              ,"BIO routines"},
90 {ERR_PACK(ERR_LIB_OBJ,0,0)              ,"object identifier routines"},
91 {ERR_PACK(ERR_LIB_PEM,0,0)              ,"PEM routines"},
92 {ERR_PACK(ERR_LIB_ASN1,0,0)             ,"asn1 encoding routines"},
93 {ERR_PACK(ERR_LIB_X509,0,0)             ,"x509 certificate routines"},
94 {ERR_PACK(ERR_LIB_CONF,0,0)             ,"configuation file routines"},
95 {ERR_PACK(ERR_LIB_METH,0,0)             ,"X509 lookup 'method' routines"},
96 {ERR_PACK(ERR_LIB_SSL,0,0)              ,"SSL routines"},
97 {ERR_PACK(ERR_LIB_RSAREF,0,0)           ,"RSAref routines"},
98 {ERR_PACK(ERR_LIB_PROXY,0,0)            ,"Proxy routines"},
99 {ERR_PACK(ERR_LIB_BIO,0,0)              ,"BIO routines"},
100 {ERR_PACK(ERR_LIB_PKCS7,0,0)            ,"PKCS7 routines"},
101 {ERR_PACK(ERR_LIB_X509V3,0,0)           ,"X509 V3 routines"},
102 {ERR_PACK(ERR_LIB_PKCS12,0,0)           ,"PKCS12 routines"},
103 {0,NULL},
104         };
105
106 static ERR_STRING_DATA ERR_str_functs[]=
107         {
108         {ERR_PACK(0,SYS_F_FOPEN,0),             "fopen"},
109         {ERR_PACK(0,SYS_F_CONNECT,0),           "connect"},
110         {ERR_PACK(0,SYS_F_GETSERVBYNAME,0),     "getservbyname"},
111         {ERR_PACK(0,SYS_F_SOCKET,0),            "socket"}, 
112         {ERR_PACK(0,SYS_F_IOCTLSOCKET,0),       "ioctlsocket"},
113         {ERR_PACK(0,SYS_F_BIND,0),              "bind"},
114         {ERR_PACK(0,SYS_F_LISTEN,0),            "listen"},
115         {ERR_PACK(0,SYS_F_ACCEPT,0),            "accept"},
116 #ifdef WINDOWS
117         {ERR_PACK(0,SYS_F_WSASTARTUP,0),        "WSAstartup"},
118 #endif
119         {ERR_PACK(0,SYS_F_OPENDIR,0),           "opendir"},
120         {0,NULL},
121         };
122
123 static ERR_STRING_DATA ERR_str_reasons[]=
124         {
125 {ERR_R_FATAL                             ,"fatal"},
126 {ERR_R_SYS_LIB                          ,"system lib"},
127 {ERR_R_BN_LIB                           ,"BN lib"},
128 {ERR_R_RSA_LIB                          ,"RSA lib"},
129 {ERR_R_DH_LIB                           ,"DH lib"},
130 {ERR_R_EVP_LIB                          ,"EVP lib"},
131 {ERR_R_BUF_LIB                          ,"BUF lib"},
132 {ERR_R_BIO_LIB                          ,"BIO lib"},
133 {ERR_R_OBJ_LIB                          ,"OBJ lib"},
134 {ERR_R_PEM_LIB                          ,"PEM lib"},
135 {ERR_R_X509_LIB                         ,"X509 lib"},
136 {ERR_R_METH_LIB                         ,"METH lib"},
137 {ERR_R_ASN1_LIB                         ,"ASN1 lib"},
138 {ERR_R_CONF_LIB                         ,"CONF lib"},
139 {ERR_R_SSL_LIB                          ,"SSL lib"},
140 {ERR_R_PROXY_LIB                        ,"PROXY lib"},
141 {ERR_R_BIO_LIB                          ,"BIO lib"},
142 {ERR_R_PKCS7_LIB                        ,"PKCS7 lib"},
143 {ERR_R_PKCS12_LIB                       ,"PKCS12 lib"},
144 {ERR_R_MALLOC_FAILURE                   ,"Malloc failure"},
145 {ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED      ,"called a function you should not call"},
146 {ERR_R_PASSED_NULL_PARAMETER            ,"passed a null parameter"},
147 {ERR_R_NESTED_ASN1_ERROR                ,"nested asn1 error"},
148 {ERR_R_BAD_ASN1_OBJECT_HEADER           ,"bad asn1 object header"},
149 {ERR_R_BAD_GET_ASN1_OBJECT_CALL         ,"bad get asn1 object call"},
150 {ERR_R_EXPECTING_AN_ASN1_SEQUENCE       ,"expecting an asn1 sequence"},
151 {ERR_R_ASN1_LENGTH_MISMATCH             ,"asn1 length mismatch"},
152 {ERR_R_MISSING_ASN1_EOS                 ,"missing asn1 eos"},
153
154 {0,NULL},
155         };
156 #endif
157
158 #define err_clear_data(p,i) \
159         if (((p)->err_data[i] != NULL) && \
160                 (p)->err_data_flags[i] & ERR_TXT_MALLOCED) \
161                 {  \
162                 Free((p)->err_data[i]); \
163                 (p)->err_data[i]=NULL; \
164                 } \
165         (p)->err_data_flags[i]=0;
166
167 static void ERR_STATE_free(ERR_STATE *s)
168         {
169         int i;
170
171         if(s == NULL)
172             return;
173
174         for (i=0; i<ERR_NUM_ERRORS; i++)
175                 {
176                 err_clear_data(s,i);
177                 }
178         Free(s);
179         }
180
181 void ERR_load_ERR_strings(void)
182         {
183         static int init=1;
184
185         if (init)
186                 {
187                 CRYPTO_w_lock(CRYPTO_LOCK_ERR);
188                 if (init == 0)
189                         {
190                         CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
191                         return;
192                         }
193                 init=0;
194                 CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
195
196 #ifndef NO_ERR
197                 ERR_load_strings(0,ERR_str_libraries);
198                 ERR_load_strings(0,ERR_str_reasons);
199                 ERR_load_strings(ERR_LIB_SYS,ERR_str_functs);
200 #endif
201                 }
202         }
203
204 void ERR_load_strings(int lib, ERR_STRING_DATA *str)
205         {
206         if (error_hash == NULL)
207                 {
208                 CRYPTO_w_lock(CRYPTO_LOCK_ERR_HASH);
209                 error_hash=lh_new(err_hash,err_cmp);
210                 if (error_hash == NULL)
211                         {
212                         CRYPTO_w_unlock(CRYPTO_LOCK_ERR_HASH);
213                         return;
214                         }
215                 CRYPTO_w_unlock(CRYPTO_LOCK_ERR_HASH);
216
217                 ERR_load_ERR_strings();
218                 }
219
220         CRYPTO_w_lock(CRYPTO_LOCK_ERR_HASH);
221         while (str->error)
222                 {
223                 str->error|=ERR_PACK(lib,0,0);
224                 lh_insert(error_hash,(char *)str);
225                 str++;
226                 }
227         CRYPTO_w_unlock(CRYPTO_LOCK_ERR_HASH);
228         }
229
230 void ERR_free_strings(void)
231         {
232         CRYPTO_w_lock(CRYPTO_LOCK_ERR);
233
234         if (error_hash != NULL)
235                 {
236                 lh_free(error_hash);
237                 error_hash=NULL;
238                 }
239
240         CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
241         }
242
243 /********************************************************/
244
245 void ERR_put_error(int lib, int func, int reason, const char *file,
246              int line)
247         {
248         ERR_STATE *es;
249
250 #ifdef _OSD_POSIX
251         /* In the BS2000-OSD POSIX subsystem, the compiler generates
252          * path names in the form "*POSIX(/etc/passwd)".
253          * This dirty hack strips them to something sensible.
254          * @@@ We shouldn't modify a const string, though.
255          */
256         if (strncmp(file,"*POSIX(", sizeof("*POSIX(")-1) == 0) {
257                 char *end;
258
259                 /* Skip the "*POSIX(" prefix */
260                 file += sizeof("*POSIX(")-1;
261                 end = &file[strlen(file)-1];
262                 if (*end == ')')
263                         *end = '\0';
264                 /* Optional: use the basename of the path only. */
265                 if ((end = strrchr(file, '/')) != NULL)
266                         file = &end[1];
267         }
268 #endif
269         es=ERR_get_state();
270
271         es->top=(es->top+1)%ERR_NUM_ERRORS;
272         if (es->top == es->bottom)
273                 es->bottom=(es->bottom+1)%ERR_NUM_ERRORS;
274         es->err_buffer[es->top]=ERR_PACK(lib,func,reason);
275         es->err_file[es->top]=file;
276         es->err_line[es->top]=line;
277         err_clear_data(es,es->top);
278         }
279
280 void ERR_clear_error(void)
281         {
282         ERR_STATE *es;
283
284         es=ERR_get_state();
285
286 #if 0
287         /* hmm... is this needed */
288         for (i=0; i<ERR_NUM_ERRORS; i++)
289                 {
290                 es->err_buffer[i]=0;
291                 es->err_file[i]=NULL;
292                 es->err_line[i]= -1;
293                 err_clear_data(es,i);
294                 }
295 #endif
296         es->top=es->bottom=0;
297         }
298
299
300 unsigned long ERR_get_error(void)
301         { return(get_error_values(1,NULL,NULL,NULL,NULL)); }
302
303 unsigned long ERR_get_error_line(const char **file,
304              int *line)
305         { return(get_error_values(1,file,line,NULL,NULL)); }
306
307 unsigned long ERR_get_error_line_data(const char **file, int *line,
308              const char **data, int *flags)
309         { return(get_error_values(1,file,line,
310              data,flags)); }
311
312 unsigned long ERR_peek_error(void)
313         { return(get_error_values(0,NULL,NULL,NULL,NULL)); }
314
315 unsigned long ERR_peek_error_line(const char **file,
316              int *line)
317         { return(get_error_values(0,file,line,NULL,NULL)); }
318
319 unsigned long ERR_peek_error_line_data(const char **file, int *line,
320              const char **data, int *flags)
321         { return(get_error_values(0,file,line,
322              data,flags)); }
323
324 static unsigned long get_error_values(int inc, const char **file, int *line,
325              const char **data, int *flags)
326         {       
327         int i=0;
328         ERR_STATE *es;
329         unsigned long ret;
330
331         es=ERR_get_state();
332
333         if (es->bottom == es->top) return(0);
334         i=(es->bottom+1)%ERR_NUM_ERRORS;
335
336         ret=es->err_buffer[i];
337         if (inc)
338                 {
339                 es->bottom=i;
340                 es->err_buffer[i]=0;
341                 }
342
343         if ((file != NULL) && (line != NULL))
344                 {
345                 if (es->err_file[i] == NULL)
346                         {
347                         *file="NA";
348                         if (line != NULL) *line=0;
349                         }
350                 else
351                         {
352                         *file=es->err_file[i];
353                         if (line != NULL) *line=es->err_line[i];
354                         }
355                 }
356
357         if (data != NULL)
358                 {
359                 if (es->err_data[i] == NULL)
360                         {
361                         *data="";
362                         if (flags != NULL) *flags=0;
363                         }
364                 else
365                         {
366                         *data=es->err_data[i];
367                         if (flags != NULL) *flags=es->err_data_flags[i];
368                         }
369                 }
370         return(ret);
371         }
372
373 /* BAD for multi-threaded, uses a local buffer if ret == NULL */
374 char *ERR_error_string(unsigned long e, char *ret)
375         {
376         static char buf[256];
377         const char *ls,*fs,*rs;
378         unsigned long l,f,r;
379         int i;
380
381         l=ERR_GET_LIB(e);
382         f=ERR_GET_FUNC(e);
383         r=ERR_GET_REASON(e);
384
385         ls=ERR_lib_error_string(e);
386         fs=ERR_func_error_string(e);
387         rs=ERR_reason_error_string(e);
388
389         if (ret == NULL) ret=buf;
390
391         sprintf(&(ret[0]),"error:%08lX:",e);
392         i=strlen(ret);
393         if (ls == NULL)
394                 sprintf(&(ret[i]),":lib(%lu) ",l);
395         else    sprintf(&(ret[i]),"%s",ls);
396         i=strlen(ret);
397         if (fs == NULL)
398                 sprintf(&(ret[i]),":func(%lu) ",f);
399         else    sprintf(&(ret[i]),":%s",fs);
400         i=strlen(ret);
401         if (rs == NULL)
402                 sprintf(&(ret[i]),":reason(%lu)",r);
403         else    sprintf(&(ret[i]),":%s",rs);
404
405         return(ret);
406         }
407
408 LHASH *ERR_get_string_table(void)
409         {
410         return(error_hash);
411         }
412
413 LHASH *ERR_get_err_state_table(void)
414         {
415         return(thread_hash);
416         }
417
418 const char *ERR_lib_error_string(unsigned long e)
419         {
420         ERR_STRING_DATA d,*p=NULL;
421         unsigned long l;
422
423         l=ERR_GET_LIB(e);
424
425         CRYPTO_r_lock(CRYPTO_LOCK_ERR_HASH);
426
427         if (error_hash != NULL)
428                 {
429                 d.error=ERR_PACK(l,0,0);
430                 p=(ERR_STRING_DATA *)lh_retrieve(error_hash,(char *)&d);
431                 }
432
433         CRYPTO_r_unlock(CRYPTO_LOCK_ERR_HASH);
434
435         return((p == NULL)?NULL:p->string);
436         }
437
438 const char *ERR_func_error_string(unsigned long e)
439         {
440         ERR_STRING_DATA d,*p=NULL;
441         unsigned long l,f;
442
443         l=ERR_GET_LIB(e);
444         f=ERR_GET_FUNC(e);
445
446         CRYPTO_r_lock(CRYPTO_LOCK_ERR_HASH);
447
448         if (error_hash != NULL)
449                 {
450                 d.error=ERR_PACK(l,f,0);
451                 p=(ERR_STRING_DATA *)lh_retrieve(error_hash,(char *)&d);
452                 }
453
454         CRYPTO_r_unlock(CRYPTO_LOCK_ERR_HASH);
455
456         return((p == NULL)?NULL:p->string);
457         }
458
459 const char *ERR_reason_error_string(unsigned long e)
460         {
461         ERR_STRING_DATA d,*p=NULL;
462         unsigned long l,r;
463
464         l=ERR_GET_LIB(e);
465         r=ERR_GET_REASON(e);
466
467         CRYPTO_r_lock(CRYPTO_LOCK_ERR_HASH);
468
469         if (error_hash != NULL)
470                 {
471                 d.error=ERR_PACK(l,0,r);
472                 p=(ERR_STRING_DATA *)lh_retrieve(error_hash,(char *)&d);
473                 if (p == NULL)
474                         {
475                         d.error=ERR_PACK(0,0,r);
476                         p=(ERR_STRING_DATA *)lh_retrieve(error_hash,
477                                 (char *)&d);
478                         }
479                 }
480
481         CRYPTO_r_unlock(CRYPTO_LOCK_ERR_HASH);
482
483         return((p == NULL)?NULL:p->string);
484         }
485
486 static unsigned long err_hash(ERR_STRING_DATA *a)
487         {
488         unsigned long ret,l;
489
490         l=a->error;
491         ret=l^ERR_GET_LIB(l)^ERR_GET_FUNC(l);
492         return(ret^ret%19*13);
493         }
494
495 static int err_cmp(ERR_STRING_DATA *a, ERR_STRING_DATA *b)
496         {
497         return((int)(a->error-b->error));
498         }
499
500 static unsigned long pid_hash(ERR_STATE *a)
501         {
502         return(a->pid*13);
503         }
504
505 static int pid_cmp(ERR_STATE *a, ERR_STATE *b)
506         {
507         return((int)((long)a->pid - (long)b->pid));
508         }
509
510 void ERR_remove_state(unsigned long pid)
511         {
512         ERR_STATE *p,tmp;
513
514         if (thread_hash == NULL)
515                 return;
516         if (pid == 0)
517                 pid=(unsigned long)CRYPTO_thread_id();
518         tmp.pid=pid;
519         CRYPTO_w_lock(CRYPTO_LOCK_ERR);
520         p=(ERR_STATE *)lh_delete(thread_hash,(char *)&tmp);
521         CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
522
523         if (p != NULL) ERR_STATE_free(p);
524         }
525
526 ERR_STATE *ERR_get_state(void)
527         {
528         static ERR_STATE fallback;
529         ERR_STATE *ret=NULL,tmp,*tmpp;
530         int i;
531         unsigned long pid;
532
533         pid=(unsigned long)CRYPTO_thread_id();
534
535         CRYPTO_r_lock(CRYPTO_LOCK_ERR);
536         if (thread_hash == NULL)
537                 {
538                 CRYPTO_r_unlock(CRYPTO_LOCK_ERR);
539                 CRYPTO_w_lock(CRYPTO_LOCK_ERR);
540                 if (thread_hash == NULL)
541                         {
542                         MemCheck_off();
543                         thread_hash=lh_new(pid_hash,pid_cmp);
544                         MemCheck_on();
545                         CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
546                         if (thread_hash == NULL) return(&fallback);
547                         }
548                 else
549                         CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
550                 }
551         else
552                 {
553                 tmp.pid=pid;
554                 ret=(ERR_STATE *)lh_retrieve(thread_hash,(char *)&tmp);
555                 CRYPTO_r_unlock(CRYPTO_LOCK_ERR);
556                 }
557
558         /* ret == the error state, if NULL, make a new one */
559         if (ret == NULL)
560                 {
561                 ret=(ERR_STATE *)Malloc(sizeof(ERR_STATE));
562                 if (ret == NULL) return(&fallback);
563                 ret->pid=pid;
564                 ret->top=0;
565                 ret->bottom=0;
566                 for (i=0; i<ERR_NUM_ERRORS; i++)
567                         {
568                         ret->err_data[i]=NULL;
569                         ret->err_data_flags[i]=0;
570                         }
571                 CRYPTO_w_lock(CRYPTO_LOCK_ERR);
572                 tmpp=(ERR_STATE *)lh_insert(thread_hash,(char *)ret);
573                 CRYPTO_w_unlock(CRYPTO_LOCK_ERR);
574                 if (tmpp != NULL) /* old entry - should not happen */
575                         {
576                         ERR_STATE_free(tmpp);
577                         }
578                 }
579         return(ret);
580         }
581
582 int ERR_get_next_error_library(void)
583         {
584         static int value=ERR_LIB_USER;
585
586         return(value++);
587         }
588
589 void ERR_set_error_data(char *data, int flags)
590         {
591         ERR_STATE *es;
592         int i;
593
594         es=ERR_get_state();
595
596         i=es->top;
597         if (i == 0)
598                 i=ERR_NUM_ERRORS-1;
599
600         es->err_data[i]=data;
601         es->err_data_flags[es->top]=flags;
602         }
603
604 void ERR_add_error_data(int num, ...)
605         {
606         va_list args;
607         int i,n,s;
608         char *str,*p,*a;
609
610         s=64;
611         str=Malloc(s+1);
612         if (str == NULL) return;
613         str[0]='\0';
614
615         va_start(args, num);
616         n=0;
617         for (i=0; i<num; i++)
618                 {
619                 a=va_arg(args, char*);
620                 /* ignore NULLs, thanks to Bob Beck <beck@obtuse.com> */
621                 if (a != NULL)
622                         {
623                         n+=strlen(a);
624                         if (n > s)
625                                 {
626                                 s=n+20;
627                                 p=Realloc(str,s+1);
628                                 if (p == NULL)
629                                         {
630                                         Free(str);
631                                         return;
632                                         }
633                                 else
634                                         str=p;
635                                 }
636                         strcat(str,a);
637                         }
638                 }
639         ERR_set_error_data(str,ERR_TXT_MALLOCED|ERR_TXT_STRING);
640
641         va_end(args);
642         }
643