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Make strerror and strerror_r use sys_errlist[0] for errnum = 0. Be

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more careful about reporting truncation with ERANGE in strerror_r.
Set errno to EINVAL for "unknown" errnum in strerror as required
by P1003.1-200x Draft June 14, 2001.

More carefully document the handling of strerrbuf when errors
(ERANGE, EINVAL) are encountered in strerror_r.

Reviewed by:	bde (ongoing discussion)
This commit is contained in:
Wes Peters 2001-12-07 06:28:58 +00:00
parent a28920935a
commit 556f162ac0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=87480
2 changed files with 32 additions and 6 deletions
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15
lib/libc/string/strerror.3
View File

@ -110,8 +110,15 @@ returns an error message string containing
.Dq Li "Unknown error:\ "
followed by the error number in decimal, while
.Fn strerror_r
returns
leaves
.Fa strerrbuf
unchanged and returns
.Er EINVAL .
Error numbers recognized by this implementation fall in
the range 0 <=
.Fa errnum
<
.Fa sys_nerr .
.Pp
If insufficient storage is provided in
.Fa strerrbuf
@ -121,9 +128,11 @@ to contain the error string,
.Fn strerror_r
returns
.Er ERANGE
and the contents of
and
.Fa strerrbuf
are indeterminate.
will contain an error message that has been truncated and nul
terminated to fit the length specified by
.Fa buflen .
.Pp
The message strings can be accessed directly using the external
array

23
lib/libc/string/strerror.c
View File

@ -46,9 +46,9 @@ strerror_r(int errnum, char *strerrbuf, size_t buflen)
{
int len;
if ((errnum > 0) && (errnum < sys_nerr)) {
if ((errnum >= 0) && (errnum < sys_nerr)) {
len = strlcpy(strerrbuf, (char *)sys_errlist[errnum], buflen);
return ((len <= buflen) ? 0 : ERANGE);
return ((len < buflen) ? 0 : ERANGE);
}
return (EINVAL);
}
@ -71,9 +71,14 @@ strerror(num)
char tmp[NUMLEN]; /* temporary number */
static char ebuf[EBUFLEN]; /* error message */
if ((num > 0) && (num < sys_nerr))
if ((num >= 0) && (num < sys_nerr))
return ((char *)sys_errlist[num]);
/*
* Set errno to EINVAL per P1003.1-200x Draft June 14, 2001.
*/
errno = EINVAL;
/*
* Print unknown errno by hand so we don't link to stdio(3).
* This collects the ASCII digits in reverse order.
@ -106,8 +111,20 @@ main()
char mybuf[64];
int ret;
errno = 0;
printf("strerror(0) yeilds: %s\n", strerror(0));
printf("strerror(1) yeilds: %s\n", strerror(1));
printf("strerror(47) yeilds: %s\n", strerror(47));
printf("strerror(sys_nerr - 1) yeilds: %s\n", strerror(sys_nerr - 1));
printf("errno = %d\n", errno); errno = 0;
printf("strerror(sys_nerr) yeilds: %s\n", strerror(sys_nerr));
printf("errno = %d\n", errno); errno = 0;
printf("strerror(437) yeilds: %s\n", strerror(437));
printf("errno = %d\n", errno); errno = 0;
printf("strerror(LONG_MAX) yeilds: %s\n", strerror(LONG_MAX));
printf("strerror(LONG_MIN) yeilds: %s\n", strerror(LONG_MIN));
printf("strerror(ULONG_MAX) yeilds: %s\n", strerror(ULONG_MAX));