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Incorporate strerror_r() into src/port/snprintf.c, too.

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This provides the features that used to exist in useful_strerror()
for users of strerror_r(), too.  Also, standardize on the GNU convention
that strerror_r returns a char pointer that may not be NULL.

I notice that libpq's win32.c contains a variant version of strerror_r
that probably ought to be folded into strerror.c.  But lacking a
Windows environment, I should leave that to somebody else.

Discussion: https://postgr.es/m/2975.1526862605@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2018-09-26 12:35:57 -04:00
parent 26e9d4d4ef
commit 758ce9b779
11 changed files with 99 additions and 83 deletions
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85
src/port/strerror.c
View File

@ -1,7 +1,7 @@
/*-------------------------------------------------------------------------
*
* strerror.c
* Replacement for standard strerror() function
* Replacements for standard strerror() and strerror_r() functions
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
@ -15,13 +15,16 @@
#include "c.h"
/*
* Within this file, "strerror" means the platform's function not pg_strerror
* Within this file, "strerror" means the platform's function not pg_strerror,
* and likewise for "strerror_r"
*/
#undef strerror
#undef strerror_r
static char *gnuish_strerror_r(int errnum, char *buf, size_t buflen);
static char *get_errno_symbol(int errnum);
#ifdef WIN32
static char *win32_socket_strerror(int errnum);
static char *win32_socket_strerror(int errnum, char *buf, size_t buflen);
#endif
@ -31,19 +34,28 @@ static char *win32_socket_strerror(int errnum);
char *
pg_strerror(int errnum)
{
/* this buffer is only used if strerror() and get_errno_symbol() fail */
static char errorstr_buf[48];
static char errorstr_buf[PG_STRERROR_R_BUFLEN];
return pg_strerror_r(errnum, errorstr_buf, sizeof(errorstr_buf));
}
/*
* A slightly cleaned-up version of strerror_r()
*/
char *
pg_strerror_r(int errnum, char *buf, size_t buflen)
{
char *str;
/* If it's a Windows Winsock error, that needs special handling */
#ifdef WIN32
/* Winsock error code range, per WinError.h */
if (errnum >= 10000 && errnum <= 11999)
return win32_socket_strerror(errnum);
return win32_socket_strerror(errnum, buf, buflen);
#endif
/* Try the platform's strerror() */
str = strerror(errnum);
/* Try the platform's strerror_r(), or maybe just strerror() */
str = gnuish_strerror_r(errnum, buf, buflen);
/*
* Some strerror()s return an empty string for out-of-range errno. This
@ -57,17 +69,42 @@ pg_strerror(int errnum)
if (str == NULL)
{
snprintf(errorstr_buf, sizeof(errorstr_buf),
/*------
translator: This string will be truncated at 47
characters expanded. */
_("operating system error %d"), errnum);
str = errorstr_buf;
snprintf(buf, buflen, _("operating system error %d"), errnum);
str = buf;
}
return str;
}
/*
* Simple wrapper to emulate GNU strerror_r if what the platform provides is
* POSIX. Also, if platform lacks strerror_r altogether, fall back to plain
* strerror; it might not be very thread-safe, but tough luck.
*/
static char *
gnuish_strerror_r(int errnum, char *buf, size_t buflen)
{
#ifdef HAVE_STRERROR_R
#ifdef STRERROR_R_INT
/* POSIX API */
if (strerror_r(errnum, buf, buflen) == 0)
return buf;
return NULL; /* let caller deal with failure */
#else
/* GNU API */
return strerror_r(errnum, buf, buflen);
#endif
#else /* !HAVE_STRERROR_R */
char *sbuf = strerror(errnum);
if (sbuf == NULL) /* can this still happen anywhere? */
return NULL;
/* To minimize thread-unsafety hazard, copy into caller's buffer */
strlcpy(buf, sbuf, buflen);
return buf;
#endif
}
/*
* Returns a symbol (e.g. "ENOENT") for an errno code.
* Returns NULL if the code is unrecognized.
@ -247,9 +284,8 @@ get_errno_symbol(int errnum)
* Windows' strerror() doesn't know the Winsock codes, so handle them this way
*/
static char *
win32_socket_strerror(int errnum)
win32_socket_strerror(int errnum, char *buf, size_t buflen)
{
static char wserrbuf[256];
static HANDLE handleDLL = INVALID_HANDLE_VALUE;
if (handleDLL == INVALID_HANDLE_VALUE)
@ -258,28 +294,29 @@ win32_socket_strerror(int errnum)
DONT_RESOLVE_DLL_REFERENCES | LOAD_LIBRARY_AS_DATAFILE);
if (handleDLL == NULL)
{
sprintf(wserrbuf, "winsock error %d (could not load netmsg.dll to translate: error code %lu)",
errnum, GetLastError());
return wserrbuf;
snprintf(buf, buflen,
"winsock error %d (could not load netmsg.dll to translate: error code %lu)",
errnum, GetLastError());
return buf;
}
}
ZeroMemory(&wserrbuf, sizeof(wserrbuf));
ZeroMemory(buf, buflen);
if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_FROM_HMODULE,
handleDLL,
errnum,
MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
wserrbuf,
sizeof(wserrbuf) - 1,
buf,
buflen - 1,
NULL) == 0)
{
/* Failed to get id */
sprintf(wserrbuf, "unrecognized winsock error %d", errnum);
snprintf(buf, buflen, "unrecognized winsock error %d", errnum);
}
return wserrbuf;
return buf;
}
#endif /* WIN32 */