1 /* Extended support for using errno values.
2    Written by Fred Fish.  fnf@cygnus.com
3    This file is in the public domain.  --Per Bothner.  */
4 
5 #include "ansidecl.h"
6 #include "libiberty.h"
7 
8 #include "config.h"
9 
10 #ifdef HAVE_SYS_ERRLIST
11 /* Note that errno.h (not sure what OS) or stdio.h (BSD 4.4, at least)
12    might declare sys_errlist in a way that the compiler might consider
13    incompatible with our later declaration, perhaps by using const
14    attributes.  So we hide the declaration in errno.h (if any) using a
15    macro. */
16 #define sys_nerr sys_nerr__
17 #define sys_errlist sys_errlist__
18 #endif
19 
20 #include <stdio.h>
21 #include <errno.h>
22 
23 #ifdef HAVE_SYS_ERRLIST
24 #undef sys_nerr
25 #undef sys_errlist
26 #endif
27 
28 /*  Routines imported from standard C runtime libraries. */
29 
30 #ifdef HAVE_STDLIB_H
31 #include <stdlib.h>
32 #else
33 extern PTR malloc ();
34 #endif
35 
36 #ifdef HAVE_STRING_H
37 #include <string.h>
38 #else
39 extern PTR memset ();
40 #endif
41 
42 #ifndef MAX
43 #  define MAX(a,b) ((a) > (b) ? (a) : (b))
44 #endif
45 
46 static void init_error_tables PARAMS ((void));
47 
48 /* Translation table for errno values.  See intro(2) in most UNIX systems
49    Programmers Reference Manuals.
50 
51    Note that this table is generally only accessed when it is used at runtime
52    to initialize errno name and message tables that are indexed by errno
53    value.
54 
55    Not all of these errnos will exist on all systems.  This table is the only
56    thing that should have to be updated as new error numbers are introduced.
57    It's sort of ugly, but at least its portable. */
58 
59 struct error_info
60 {
61   const int value;		/* The numeric value from <errno.h> */
62   const char *const name;	/* The equivalent symbolic value */
63 #ifndef HAVE_SYS_ERRLIST
64   const char *const msg;	/* Short message about this value */
65 #endif
66 };
67 
68 #ifndef HAVE_SYS_ERRLIST
69 #   define ENTRY(value, name, msg)	{value, name, msg}
70 #else
71 #   define ENTRY(value, name, msg)	{value, name}
72 #endif
73 
74 static const struct error_info error_table[] =
75 {
76 #if defined (EPERM)
77   ENTRY(EPERM, "EPERM", "Not owner"),
78 #endif
79 #if defined (ENOENT)
80   ENTRY(ENOENT, "ENOENT", "No such file or directory"),
81 #endif
82 #if defined (ESRCH)
83   ENTRY(ESRCH, "ESRCH", "No such process"),
84 #endif
85 #if defined (EINTR)
86   ENTRY(EINTR, "EINTR", "Interrupted system call"),
87 #endif
88 #if defined (EIO)
89   ENTRY(EIO, "EIO", "I/O error"),
90 #endif
91 #if defined (ENXIO)
92   ENTRY(ENXIO, "ENXIO", "No such device or address"),
93 #endif
94 #if defined (E2BIG)
95   ENTRY(E2BIG, "E2BIG", "Arg list too long"),
96 #endif
97 #if defined (ENOEXEC)
98   ENTRY(ENOEXEC, "ENOEXEC", "Exec format error"),
99 #endif
100 #if defined (EBADF)
101   ENTRY(EBADF, "EBADF", "Bad file number"),
102 #endif
103 #if defined (ECHILD)
104   ENTRY(ECHILD, "ECHILD", "No child processes"),
105 #endif
106 #if defined (EWOULDBLOCK)	/* Put before EAGAIN, sometimes aliased */
107   ENTRY(EWOULDBLOCK, "EWOULDBLOCK", "Operation would block"),
108 #endif
109 #if defined (EAGAIN)
110   ENTRY(EAGAIN, "EAGAIN", "No more processes"),
111 #endif
112 #if defined (ENOMEM)
113   ENTRY(ENOMEM, "ENOMEM", "Not enough space"),
114 #endif
115 #if defined (EACCES)
116   ENTRY(EACCES, "EACCES", "Permission denied"),
117 #endif
118 #if defined (EFAULT)
119   ENTRY(EFAULT, "EFAULT", "Bad address"),
120 #endif
121 #if defined (ENOTBLK)
122   ENTRY(ENOTBLK, "ENOTBLK", "Block device required"),
123 #endif
124 #if defined (EBUSY)
125   ENTRY(EBUSY, "EBUSY", "Device busy"),
126 #endif
127 #if defined (EEXIST)
128   ENTRY(EEXIST, "EEXIST", "File exists"),
129 #endif
130 #if defined (EXDEV)
131   ENTRY(EXDEV, "EXDEV", "Cross-device link"),
132 #endif
133 #if defined (ENODEV)
134   ENTRY(ENODEV, "ENODEV", "No such device"),
135 #endif
136 #if defined (ENOTDIR)
137   ENTRY(ENOTDIR, "ENOTDIR", "Not a directory"),
138 #endif
139 #if defined (EISDIR)
140   ENTRY(EISDIR, "EISDIR", "Is a directory"),
141 #endif
142 #if defined (EINVAL)
143   ENTRY(EINVAL, "EINVAL", "Invalid argument"),
144 #endif
145 #if defined (ENFILE)
146   ENTRY(ENFILE, "ENFILE", "File table overflow"),
147 #endif
148 #if defined (EMFILE)
149   ENTRY(EMFILE, "EMFILE", "Too many open files"),
150 #endif
151 #if defined (ENOTTY)
152   ENTRY(ENOTTY, "ENOTTY", "Not a typewriter"),
153 #endif
154 #if defined (ETXTBSY)
155   ENTRY(ETXTBSY, "ETXTBSY", "Text file busy"),
156 #endif
157 #if defined (EFBIG)
158   ENTRY(EFBIG, "EFBIG", "File too large"),
159 #endif
160 #if defined (ENOSPC)
161   ENTRY(ENOSPC, "ENOSPC", "No space left on device"),
162 #endif
163 #if defined (ESPIPE)
164   ENTRY(ESPIPE, "ESPIPE", "Illegal seek"),
165 #endif
166 #if defined (EROFS)
167   ENTRY(EROFS, "EROFS", "Read-only file system"),
168 #endif
169 #if defined (EMLINK)
170   ENTRY(EMLINK, "EMLINK", "Too many links"),
171 #endif
172 #if defined (EPIPE)
173   ENTRY(EPIPE, "EPIPE", "Broken pipe"),
174 #endif
175 #if defined (EDOM)
176   ENTRY(EDOM, "EDOM", "Math argument out of domain of func"),
177 #endif
178 #if defined (ERANGE)
179   ENTRY(ERANGE, "ERANGE", "Math result not representable"),
180 #endif
181 #if defined (ENOMSG)
182   ENTRY(ENOMSG, "ENOMSG", "No message of desired type"),
183 #endif
184 #if defined (EIDRM)
185   ENTRY(EIDRM, "EIDRM", "Identifier removed"),
186 #endif
187 #if defined (ECHRNG)
188   ENTRY(ECHRNG, "ECHRNG", "Channel number out of range"),
189 #endif
190 #if defined (EL2NSYNC)
191   ENTRY(EL2NSYNC, "EL2NSYNC", "Level 2 not synchronized"),
192 #endif
193 #if defined (EL3HLT)
194   ENTRY(EL3HLT, "EL3HLT", "Level 3 halted"),
195 #endif
196 #if defined (EL3RST)
197   ENTRY(EL3RST, "EL3RST", "Level 3 reset"),
198 #endif
199 #if defined (ELNRNG)
200   ENTRY(ELNRNG, "ELNRNG", "Link number out of range"),
201 #endif
202 #if defined (EUNATCH)
203   ENTRY(EUNATCH, "EUNATCH", "Protocol driver not attached"),
204 #endif
205 #if defined (ENOCSI)
206   ENTRY(ENOCSI, "ENOCSI", "No CSI structure available"),
207 #endif
208 #if defined (EL2HLT)
209   ENTRY(EL2HLT, "EL2HLT", "Level 2 halted"),
210 #endif
211 #if defined (EDEADLK)
212   ENTRY(EDEADLK, "EDEADLK", "Deadlock condition"),
213 #endif
214 #if defined (ENOLCK)
215   ENTRY(ENOLCK, "ENOLCK", "No record locks available"),
216 #endif
217 #if defined (EBADE)
218   ENTRY(EBADE, "EBADE", "Invalid exchange"),
219 #endif
220 #if defined (EBADR)
221   ENTRY(EBADR, "EBADR", "Invalid request descriptor"),
222 #endif
223 #if defined (EXFULL)
224   ENTRY(EXFULL, "EXFULL", "Exchange full"),
225 #endif
226 #if defined (ENOANO)
227   ENTRY(ENOANO, "ENOANO", "No anode"),
228 #endif
229 #if defined (EBADRQC)
230   ENTRY(EBADRQC, "EBADRQC", "Invalid request code"),
231 #endif
232 #if defined (EBADSLT)
233   ENTRY(EBADSLT, "EBADSLT", "Invalid slot"),
234 #endif
235 #if defined (EDEADLOCK)
236   ENTRY(EDEADLOCK, "EDEADLOCK", "File locking deadlock error"),
237 #endif
238 #if defined (EBFONT)
239   ENTRY(EBFONT, "EBFONT", "Bad font file format"),
240 #endif
241 #if defined (ENOSTR)
242   ENTRY(ENOSTR, "ENOSTR", "Device not a stream"),
243 #endif
244 #if defined (ENODATA)
245   ENTRY(ENODATA, "ENODATA", "No data available"),
246 #endif
247 #if defined (ETIME)
248   ENTRY(ETIME, "ETIME", "Timer expired"),
249 #endif
250 #if defined (ENOSR)
251   ENTRY(ENOSR, "ENOSR", "Out of streams resources"),
252 #endif
253 #if defined (ENONET)
254   ENTRY(ENONET, "ENONET", "Machine is not on the network"),
255 #endif
256 #if defined (ENOPKG)
257   ENTRY(ENOPKG, "ENOPKG", "Package not installed"),
258 #endif
259 #if defined (EREMOTE)
260   ENTRY(EREMOTE, "EREMOTE", "Object is remote"),
261 #endif
262 #if defined (ENOLINK)
263   ENTRY(ENOLINK, "ENOLINK", "Link has been severed"),
264 #endif
265 #if defined (EADV)
266   ENTRY(EADV, "EADV", "Advertise error"),
267 #endif
268 #if defined (ESRMNT)
269   ENTRY(ESRMNT, "ESRMNT", "Srmount error"),
270 #endif
271 #if defined (ECOMM)
272   ENTRY(ECOMM, "ECOMM", "Communication error on send"),
273 #endif
274 #if defined (EPROTO)
275   ENTRY(EPROTO, "EPROTO", "Protocol error"),
276 #endif
277 #if defined (EMULTIHOP)
278   ENTRY(EMULTIHOP, "EMULTIHOP", "Multihop attempted"),
279 #endif
280 #if defined (EDOTDOT)
281   ENTRY(EDOTDOT, "EDOTDOT", "RFS specific error"),
282 #endif
283 #if defined (EBADMSG)
284   ENTRY(EBADMSG, "EBADMSG", "Not a data message"),
285 #endif
286 #if defined (ENAMETOOLONG)
287   ENTRY(ENAMETOOLONG, "ENAMETOOLONG", "File name too long"),
288 #endif
289 #if defined (EOVERFLOW)
290   ENTRY(EOVERFLOW, "EOVERFLOW", "Value too large for defined data type"),
291 #endif
292 #if defined (ENOTUNIQ)
293   ENTRY(ENOTUNIQ, "ENOTUNIQ", "Name not unique on network"),
294 #endif
295 #if defined (EBADFD)
296   ENTRY(EBADFD, "EBADFD", "File descriptor in bad state"),
297 #endif
298 #if defined (EREMCHG)
299   ENTRY(EREMCHG, "EREMCHG", "Remote address changed"),
300 #endif
301 #if defined (ELIBACC)
302   ENTRY(ELIBACC, "ELIBACC", "Can not access a needed shared library"),
303 #endif
304 #if defined (ELIBBAD)
305   ENTRY(ELIBBAD, "ELIBBAD", "Accessing a corrupted shared library"),
306 #endif
307 #if defined (ELIBSCN)
308   ENTRY(ELIBSCN, "ELIBSCN", ".lib section in a.out corrupted"),
309 #endif
310 #if defined (ELIBMAX)
311   ENTRY(ELIBMAX, "ELIBMAX", "Attempting to link in too many shared libraries"),
312 #endif
313 #if defined (ELIBEXEC)
314   ENTRY(ELIBEXEC, "ELIBEXEC", "Cannot exec a shared library directly"),
315 #endif
316 #if defined (EILSEQ)
317   ENTRY(EILSEQ, "EILSEQ", "Illegal byte sequence"),
318 #endif
319 #if defined (ENOSYS)
320   ENTRY(ENOSYS, "ENOSYS", "Operation not applicable"),
321 #endif
322 #if defined (ELOOP)
323   ENTRY(ELOOP, "ELOOP", "Too many symbolic links encountered"),
324 #endif
325 #if defined (ERESTART)
326   ENTRY(ERESTART, "ERESTART", "Interrupted system call should be restarted"),
327 #endif
328 #if defined (ESTRPIPE)
329   ENTRY(ESTRPIPE, "ESTRPIPE", "Streams pipe error"),
330 #endif
331 #if defined (ENOTEMPTY)
332   ENTRY(ENOTEMPTY, "ENOTEMPTY", "Directory not empty"),
333 #endif
334 #if defined (EUSERS)
335   ENTRY(EUSERS, "EUSERS", "Too many users"),
336 #endif
337 #if defined (ENOTSOCK)
338   ENTRY(ENOTSOCK, "ENOTSOCK", "Socket operation on non-socket"),
339 #endif
340 #if defined (EDESTADDRREQ)
341   ENTRY(EDESTADDRREQ, "EDESTADDRREQ", "Destination address required"),
342 #endif
343 #if defined (EMSGSIZE)
344   ENTRY(EMSGSIZE, "EMSGSIZE", "Message too long"),
345 #endif
346 #if defined (EPROTOTYPE)
347   ENTRY(EPROTOTYPE, "EPROTOTYPE", "Protocol wrong type for socket"),
348 #endif
349 #if defined (ENOPROTOOPT)
350   ENTRY(ENOPROTOOPT, "ENOPROTOOPT", "Protocol not available"),
351 #endif
352 #if defined (EPROTONOSUPPORT)
353   ENTRY(EPROTONOSUPPORT, "EPROTONOSUPPORT", "Protocol not supported"),
354 #endif
355 #if defined (ESOCKTNOSUPPORT)
356   ENTRY(ESOCKTNOSUPPORT, "ESOCKTNOSUPPORT", "Socket type not supported"),
357 #endif
358 #if defined (EOPNOTSUPP)
359   ENTRY(EOPNOTSUPP, "EOPNOTSUPP", "Operation not supported on transport endpoint"),
360 #endif
361 #if defined (EPFNOSUPPORT)
362   ENTRY(EPFNOSUPPORT, "EPFNOSUPPORT", "Protocol family not supported"),
363 #endif
364 #if defined (EAFNOSUPPORT)
365   ENTRY(EAFNOSUPPORT, "EAFNOSUPPORT", "Address family not supported by protocol"),
366 #endif
367 #if defined (EADDRINUSE)
368   ENTRY(EADDRINUSE, "EADDRINUSE", "Address already in use"),
369 #endif
370 #if defined (EADDRNOTAVAIL)
371   ENTRY(EADDRNOTAVAIL, "EADDRNOTAVAIL","Cannot assign requested address"),
372 #endif
373 #if defined (ENETDOWN)
374   ENTRY(ENETDOWN, "ENETDOWN", "Network is down"),
375 #endif
376 #if defined (ENETUNREACH)
377   ENTRY(ENETUNREACH, "ENETUNREACH", "Network is unreachable"),
378 #endif
379 #if defined (ENETRESET)
380   ENTRY(ENETRESET, "ENETRESET", "Network dropped connection because of reset"),
381 #endif
382 #if defined (ECONNABORTED)
383   ENTRY(ECONNABORTED, "ECONNABORTED", "Software caused connection abort"),
384 #endif
385 #if defined (ECONNRESET)
386   ENTRY(ECONNRESET, "ECONNRESET", "Connection reset by peer"),
387 #endif
388 #if defined (ENOBUFS)
389   ENTRY(ENOBUFS, "ENOBUFS", "No buffer space available"),
390 #endif
391 #if defined (EISCONN)
392   ENTRY(EISCONN, "EISCONN", "Transport endpoint is already connected"),
393 #endif
394 #if defined (ENOTCONN)
395   ENTRY(ENOTCONN, "ENOTCONN", "Transport endpoint is not connected"),
396 #endif
397 #if defined (ESHUTDOWN)
398   ENTRY(ESHUTDOWN, "ESHUTDOWN", "Cannot send after transport endpoint shutdown"),
399 #endif
400 #if defined (ETOOMANYREFS)
401   ENTRY(ETOOMANYREFS, "ETOOMANYREFS", "Too many references: cannot splice"),
402 #endif
403 #if defined (ETIMEDOUT)
404   ENTRY(ETIMEDOUT, "ETIMEDOUT", "Connection timed out"),
405 #endif
406 #if defined (ECONNREFUSED)
407   ENTRY(ECONNREFUSED, "ECONNREFUSED", "Connection refused"),
408 #endif
409 #if defined (EHOSTDOWN)
410   ENTRY(EHOSTDOWN, "EHOSTDOWN", "Host is down"),
411 #endif
412 #if defined (EHOSTUNREACH)
413   ENTRY(EHOSTUNREACH, "EHOSTUNREACH", "No route to host"),
414 #endif
415 #if defined (EALREADY)
416   ENTRY(EALREADY, "EALREADY", "Operation already in progress"),
417 #endif
418 #if defined (EINPROGRESS)
419   ENTRY(EINPROGRESS, "EINPROGRESS", "Operation now in progress"),
420 #endif
421 #if defined (ESTALE)
422   ENTRY(ESTALE, "ESTALE", "Stale NFS file handle"),
423 #endif
424 #if defined (EUCLEAN)
425   ENTRY(EUCLEAN, "EUCLEAN", "Structure needs cleaning"),
426 #endif
427 #if defined (ENOTNAM)
428   ENTRY(ENOTNAM, "ENOTNAM", "Not a XENIX named type file"),
429 #endif
430 #if defined (ENAVAIL)
431   ENTRY(ENAVAIL, "ENAVAIL", "No XENIX semaphores available"),
432 #endif
433 #if defined (EISNAM)
434   ENTRY(EISNAM, "EISNAM", "Is a named type file"),
435 #endif
436 #if defined (EREMOTEIO)
437   ENTRY(EREMOTEIO, "EREMOTEIO", "Remote I/O error"),
438 #endif
439   ENTRY(0, NULL, NULL)
440 };
441 
442 #ifdef EVMSERR
443 /* This is not in the table, because the numeric value of EVMSERR (32767)
444    lies outside the range of sys_errlist[].  */
445 static struct { int value; const char *name, *msg; }
446   evmserr = { EVMSERR, "EVMSERR", "VMS-specific error" };
447 #endif
448 
449 /* Translation table allocated and initialized at runtime.  Indexed by the
450    errno value to find the equivalent symbolic value. */
451 
452 static const char **error_names;
453 static int num_error_names = 0;
454 
455 /* Translation table allocated and initialized at runtime, if it does not
456    already exist in the host environment.  Indexed by the errno value to find
457    the descriptive string.
458 
459    We don't export it for use in other modules because even though it has the
460    same name, it differs from other implementations in that it is dynamically
461    initialized rather than statically initialized. */
462 
463 #ifndef HAVE_SYS_ERRLIST
464 
465 #define sys_nerr sys_nerr__
466 #define sys_errlist sys_errlist__
467 static int sys_nerr;
468 static const char **sys_errlist;
469 
470 #else
471 
472 extern int sys_nerr;
473 extern char *sys_errlist[];
474 
475 #endif
476 
477 /*
478 
479 NAME
480 
481 	init_error_tables -- initialize the name and message tables
482 
483 SYNOPSIS
484 
485 	static void init_error_tables ();
486 
487 DESCRIPTION
488 
489 	Using the error_table, which is initialized at compile time, generate
490 	the error_names and the sys_errlist (if needed) tables, which are
491 	indexed at runtime by a specific errno value.
492 
493 BUGS
494 
495 	The initialization of the tables may fail under low memory conditions,
496 	in which case we don't do anything particularly useful, but we don't
497 	bomb either.  Who knows, it might succeed at a later point if we free
498 	some memory in the meantime.  In any case, the other routines know
499 	how to deal with lack of a table after trying to initialize it.  This
500 	may or may not be considered to be a bug, that we don't specifically
501 	warn about this particular failure mode.
502 
503 */
504 
505 static void
506 init_error_tables ()
507 {
508   const struct error_info *eip;
509   int nbytes;
510 
511   /* If we haven't already scanned the error_table once to find the maximum
512      errno value, then go find it now. */
513 
514   if (num_error_names == 0)
515     {
516       for (eip = error_table; eip -> name != NULL; eip++)
517 	{
518 	  if (eip -> value >= num_error_names)
519 	    {
520 	      num_error_names = eip -> value + 1;
521 	    }
522 	}
523     }
524 
525   /* Now attempt to allocate the error_names table, zero it out, and then
526      initialize it from the statically initialized error_table. */
527 
528   if (error_names == NULL)
529     {
530       nbytes = num_error_names * sizeof (char *);
531       if ((error_names = (const char **) malloc (nbytes)) != NULL)
532 	{
533 	  memset (error_names, 0, nbytes);
534 	  for (eip = error_table; eip -> name != NULL; eip++)
535 	    {
536 	      error_names[eip -> value] = eip -> name;
537 	    }
538 	}
539     }
540 
541 #ifndef HAVE_SYS_ERRLIST
542 
543   /* Now attempt to allocate the sys_errlist table, zero it out, and then
544      initialize it from the statically initialized error_table. */
545 
546   if (sys_errlist == NULL)
547     {
548       nbytes = num_error_names * sizeof (char *);
549       if ((sys_errlist = (const char **) malloc (nbytes)) != NULL)
550 	{
551 	  memset (sys_errlist, 0, nbytes);
552 	  sys_nerr = num_error_names;
553 	  for (eip = error_table; eip -> name != NULL; eip++)
554 	    {
555 	      sys_errlist[eip -> value] = eip -> msg;
556 	    }
557 	}
558     }
559 
560 #endif
561 
562 }
563 
564 /*
565 
566 
567 @deftypefn Extension int errno_max (void)
568 
569 Returns the maximum @code{errno} value for which a corresponding
570 symbolic name or message is available.  Note that in the case where we
571 use the @code{sys_errlist} supplied by the system, it is possible for
572 there to be more symbolic names than messages, or vice versa.  In
573 fact, the manual page for @code{perror(3C)} explicitly warns that one
574 should check the size of the table (@code{sys_nerr}) before indexing
575 it, since new error codes may be added to the system before they are
576 added to the table.  Thus @code{sys_nerr} might be smaller than value
577 implied by the largest @code{errno} value defined in @code{<errno.h>}.
578 
579 We return the maximum value that can be used to obtain a meaningful
580 symbolic name or message.
581 
582 @end deftypefn
583 
584 */
585 
586 int
587 errno_max ()
588 {
589   int maxsize;
590 
591   if (error_names == NULL)
592     {
593       init_error_tables ();
594     }
595   maxsize = MAX (sys_nerr, num_error_names);
596   return (maxsize - 1);
597 }
598 
599 #ifndef HAVE_STRERROR
600 
601 /*
602 
603 @deftypefn Supplemental char* strerror (int @var{errnoval})
604 
605 Maps an @code{errno} number to an error message string, the contents
606 of which are implementation defined.  On systems which have the
607 external variables @code{sys_nerr} and @code{sys_errlist}, these
608 strings will be the same as the ones used by @code{perror}.
609 
610 If the supplied error number is within the valid range of indices for
611 the @code{sys_errlist}, but no message is available for the particular
612 error number, then returns the string @samp{Error @var{num}}, where
613 @var{num} is the error number.
614 
615 If the supplied error number is not a valid index into
616 @code{sys_errlist}, returns @code{NULL}.
617 
618 The returned string is only guaranteed to be valid only until the
619 next call to @code{strerror}.
620 
621 @end deftypefn
622 
623 */
624 
625 char *
626 strerror (errnoval)
627   int errnoval;
628 {
629   const char *msg;
630   static char buf[32];
631 
632 #ifndef HAVE_SYS_ERRLIST
633 
634   if (error_names == NULL)
635     {
636       init_error_tables ();
637     }
638 
639 #endif
640 
641   if ((errnoval < 0) || (errnoval >= sys_nerr))
642     {
643 #ifdef EVMSERR
644       if (errnoval == evmserr.value)
645 	msg = evmserr.msg;
646       else
647 #endif
648       /* Out of range, just return NULL */
649       msg = NULL;
650     }
651   else if ((sys_errlist == NULL) || (sys_errlist[errnoval] == NULL))
652     {
653       /* In range, but no sys_errlist or no entry at this index. */
654       sprintf (buf, "Error %d", errnoval);
655       msg = buf;
656     }
657   else
658     {
659       /* In range, and a valid message.  Just return the message. */
660       msg = (char *) sys_errlist[errnoval];
661     }
662 
663   return (msg);
664 }
665 
666 #endif	/* ! HAVE_STRERROR */
667 
668 
669 /*
670 
671 @deftypefn Replacement {const char*} strerrno (int @var{errnum})
672 
673 Given an error number returned from a system call (typically returned
674 in @code{errno}), returns a pointer to a string containing the
675 symbolic name of that error number, as found in @code{<errno.h>}.
676 
677 If the supplied error number is within the valid range of indices for
678 symbolic names, but no name is available for the particular error
679 number, then returns the string @samp{Error @var{num}}, where @var{num}
680 is the error number.
681 
682 If the supplied error number is not within the range of valid
683 indices, then returns @code{NULL}.
684 
685 The contents of the location pointed to are only guaranteed to be
686 valid until the next call to @code{strerrno}.
687 
688 @end deftypefn
689 
690 */
691 
692 const char *
693 strerrno (errnoval)
694   int errnoval;
695 {
696   const char *name;
697   static char buf[32];
698 
699   if (error_names == NULL)
700     {
701       init_error_tables ();
702     }
703 
704   if ((errnoval < 0) || (errnoval >= num_error_names))
705     {
706 #ifdef EVMSERR
707       if (errnoval == evmserr.value)
708 	name = evmserr.name;
709       else
710 #endif
711       /* Out of range, just return NULL */
712       name = NULL;
713     }
714   else if ((error_names == NULL) || (error_names[errnoval] == NULL))
715     {
716       /* In range, but no error_names or no entry at this index. */
717       sprintf (buf, "Error %d", errnoval);
718       name = (const char *) buf;
719     }
720   else
721     {
722       /* In range, and a valid name.  Just return the name. */
723       name = error_names[errnoval];
724     }
725 
726   return (name);
727 }
728 
729 /*
730 
731 @deftypefn Extension int strtoerrno (const char *@var{name})
732 
733 Given the symbolic name of a error number (e.g., @code{EACCES}), map it
734 to an errno value.  If no translation is found, returns 0.
735 
736 @end deftypefn
737 
738 */
739 
740 int
741 strtoerrno (name)
742      const char *name;
743 {
744   int errnoval = 0;
745 
746   if (name != NULL)
747     {
748       if (error_names == NULL)
749 	{
750 	  init_error_tables ();
751 	}
752       for (errnoval = 0; errnoval < num_error_names; errnoval++)
753 	{
754 	  if ((error_names[errnoval] != NULL) &&
755 	      (strcmp (name, error_names[errnoval]) == 0))
756 	    {
757 	      break;
758 	    }
759 	}
760       if (errnoval == num_error_names)
761 	{
762 #ifdef EVMSERR
763 	  if (strcmp (name, evmserr.name) == 0)
764 	    errnoval = evmserr.value;
765 	  else
766 #endif
767 	  errnoval = 0;
768 	}
769     }
770   return (errnoval);
771 }
772 
773 
774 /* A simple little main that does nothing but print all the errno translations
775    if MAIN is defined and this file is compiled and linked. */
776 
777 #ifdef MAIN
778 
779 #include <stdio.h>
780 
781 int
782 main ()
783 {
784   int errn;
785   int errnmax;
786   const char *name;
787   const char *msg;
788   char *strerror ();
789 
790   errnmax = errno_max ();
791   printf ("%d entries in names table.\n", num_error_names);
792   printf ("%d entries in messages table.\n", sys_nerr);
793   printf ("%d is max useful index.\n", errnmax);
794 
795   /* Keep printing values until we get to the end of *both* tables, not
796      *either* table.  Note that knowing the maximum useful index does *not*
797      relieve us of the responsibility of testing the return pointer for
798      NULL. */
799 
800   for (errn = 0; errn <= errnmax; errn++)
801     {
802       name = strerrno (errn);
803       name = (name == NULL) ? "<NULL>" : name;
804       msg = strerror (errn);
805       msg = (msg == NULL) ? "<NULL>" : msg;
806       printf ("%-4d%-18s%s\n", errn, name, msg);
807     }
808 
809   return 0;
810 }
811 
812 #endif
813