svn commit: r342551 - in head/lib/libc: gen include string

[Konstantin Belousov]

Author: kib
Date: Thu Dec 27 13:02:15 2018
New Revision: 342551
URL: https://svnweb.freebsd.org/changeset/base/342551

Log:
  Bump sys_errlist size to keep ABI backward-compatible for some time.
  
  Addition of the new errno values requires adding new elements to
  sys_errlist array, which is actually ABI-incompatible, since ELF
  records the object size.  Expand array in advance to 150 elements so
  that we have our users to go over the issue only once, at least until
  more than 53 new errors are added.
  
  I did not bumped the symbol version, same as it was not done for
  previous increases of the array size.  Runtime linker only copies as
  much data into binary object on copy relocation as the binary'object
  specifies.  This is not fixable for binaries which access sys_errlist
  directly.
  
  While there, correct comment and calculation of the temporary buffer
  size for the message printed for unknown error.  The on-stack buffer
  is used only for the number and delimiter since r108603.
  
  Requested by:	mckusick
  Reviewed by:	mckusick, yuripv
  MFC after:	2 weeks
  Sponsored by:	The FreeBSD Foundation
  Differential revision:	https://reviews.freebsd.org/D18656

Modified:
  head/lib/libc/gen/errlst.c
  head/lib/libc/include/errlst.h
  head/lib/libc/string/strerror.c

Modified: head/lib/libc/gen/errlst.c
==============================================================================
--- head/lib/libc/gen/errlst.c	Thu Dec 27 08:48:54 2018	(r342550)
+++ head/lib/libc/gen/errlst.c	Thu Dec 27 13:02:15 2018	(r342551)
@@ -33,9 +33,12 @@
 __SCCSID("@(#)errlst.c	8.2 (Berkeley) 11/16/93");
 __FBSDID("$FreeBSD$");
 
+#include <errno.h>
 #include <stdio.h>
 #include "errlst.h"
 
+const char __uprefix[] = "Unknown error";
+
 const char *const sys_errlist[] = {
 	"No error: 0",				/*  0 - ENOERROR */
 	"Operation not permitted",		/*  1 - EPERM */
@@ -155,8 +158,67 @@ const char *const sys_errlist[] = {
 	"Not permitted in capability mode",	/* 94 - ECAPMODE */
 	"State not recoverable",		/* 95 - ENOTRECOVERABLE */
 	"Previous owner died",			/* 96 - EOWNERDEAD */
+
+/*
+ * Reserved space in sys_errlist, take the next slot for a next error code.
+ * Reserve prevents the array size from changing for some time.
+ */
+	__uprefix,				/* 97 */
+	__uprefix,				/* 98 */
+	__uprefix,				/* 99 */
+	__uprefix,				/* 100 */
+	__uprefix,				/* 101 */
+	__uprefix,				/* 102 */
+	__uprefix,				/* 103 */
+	__uprefix,				/* 104 */
+	__uprefix,				/* 105 */
+	__uprefix,				/* 106 */
+	__uprefix,				/* 107 */
+	__uprefix,				/* 108 */
+	__uprefix,				/* 109 */
+	__uprefix,				/* 110 */
+	__uprefix,				/* 111 */
+	__uprefix,				/* 112 */
+	__uprefix,				/* 113 */
+	__uprefix,				/* 114 */
+	__uprefix,				/* 115 */
+	__uprefix,				/* 116 */
+	__uprefix,				/* 117 */
+	__uprefix,				/* 118 */
+	__uprefix,				/* 119 */
+	__uprefix,				/* 120 */
+	__uprefix,				/* 121 */
+	__uprefix,				/* 122 */
+	__uprefix,				/* 123 */
+	__uprefix,				/* 124 */
+	__uprefix,				/* 125 */
+	__uprefix,				/* 126 */
+	__uprefix,				/* 127 */
+	__uprefix,				/* 128 */
+	__uprefix,				/* 129 */
+	__uprefix,				/* 130 */
+	__uprefix,				/* 131 */
+	__uprefix,				/* 132 */
+	__uprefix,				/* 133 */
+	__uprefix,				/* 134 */
+	__uprefix,				/* 135 */
+	__uprefix,				/* 136 */
+	__uprefix,				/* 137 */
+	__uprefix,				/* 138 */
+	__uprefix,				/* 139 */
+	__uprefix,				/* 140 */
+	__uprefix,				/* 141 */
+	__uprefix,				/* 142 */
+	__uprefix,				/* 143 */
+	__uprefix,				/* 144 */
+	__uprefix,				/* 145 */
+	__uprefix,				/* 146 */
+	__uprefix,				/* 147 */
+	__uprefix,				/* 148 */
+	__uprefix,				/* 149 */
+	__uprefix,				/* 150 */
 };
-const int sys_nerr = sizeof(sys_errlist) / sizeof(sys_errlist[0]);
+const int sys_nerr = ELAST + 1;
 
 #ifdef PIC
 __strong_reference(sys_errlist, __hidden_sys_errlist);

Modified: head/lib/libc/include/errlst.h
==============================================================================
--- head/lib/libc/include/errlst.h	Thu Dec 27 08:48:54 2018	(r342550)
+++ head/lib/libc/include/errlst.h	Thu Dec 27 13:02:15 2018	(r342551)
@@ -42,4 +42,6 @@ extern const int __hidden_sys_nerr __hidden;
 #define __hidden_sys_nerr sys_nerr
 #endif
 
+extern const char __uprefix[] __hidden;
+
 #endif /* __ERRLST_H__ */

Modified: head/lib/libc/string/strerror.c
==============================================================================
--- head/lib/libc/string/strerror.c	Thu Dec 27 08:48:54 2018	(r342550)
+++ head/lib/libc/string/strerror.c	Thu Dec 27 13:02:15 2018	(r342551)
@@ -46,15 +46,12 @@ __FBSDID("$FreeBSD$");
 
 #include "errlst.h"
 
-#define	UPREFIX		"Unknown error"
-
 /*
- * Define a buffer size big enough to describe a 64-bit signed integer
- * converted to ASCII decimal (19 bytes), with an optional leading sign
- * (1 byte); finally, we get the prefix, delimiter (": ") and a trailing
- * NUL from UPREFIX.
+ * Define buffer big enough to contain delimiter (": ", 2 bytes),
+ * 64-bit signed integer converted to ASCII decimal (19 bytes) with
+ * optional leading sign (1 byte), and a trailing NUL.
  */
-#define	EBUFSIZE	(20 + 2 + sizeof(UPREFIX))
+#define	EBUFSIZE	(2 + 19 + 1 + 1)
 
 /*
  * Doing this by hand instead of linking with stdio(3) avoids bloat for
@@ -94,9 +91,9 @@ strerror_r(int errnum, char *strerrbuf, size_t buflen)
 	if (errnum < 0 || errnum >= __hidden_sys_nerr) {
 		errstr(errnum,
 #if defined(NLS)
-			catgets(catd, 1, 0xffff, UPREFIX),
+			catgets(catd, 1, 0xffff, __uprefix),
 #else
-			UPREFIX,
+		        __uprefix,
 #endif
 			strerrbuf, buflen);
 		retval = EINVAL;