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Fix pg_strtof() to not crash on NULL endptr.

We had managed not to notice this simple oversight because none
of our calls exercised the case --- until commit 8f427187d.
That led to pg_dump crashing on any platform that uses this code
(currently Cygwin and Mingw).

Even though there's no immediate bug in the back branches, backpatch,
because a non-POSIX-compliant strtof() substitute is trouble waiting
to happen for extensions or future back-patches.

Diagnosed-by: Alexander Lakhin <exclusion@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/339b3902-4e98-4e31-a744-94e43b7b9292@gmail.com
Backpatch-through: 13
This commit is contained in:
Tom Lane 2025-03-01 14:22:56 -05:00
parent ee78823ff5
commit d69c781084

View File

@ -31,15 +31,18 @@ pg_strtof(const char *nptr, char **endptr)
{
int caller_errno = errno;
float fresult;
char *myendptr;
errno = 0;
fresult = (strtof) (nptr, endptr);
fresult = (strtof) (nptr, &myendptr);
if (endptr)
*endptr = myendptr;
if (errno)
{
/* On error, just return the error to the caller. */
return fresult;
}
else if ((*endptr == nptr) || isnan(fresult) ||
else if ((myendptr == nptr) || isnan(fresult) ||
((fresult >= FLT_MIN || fresult <= -FLT_MIN) && !isinf(fresult)))
{
/*
@ -53,7 +56,8 @@ pg_strtof(const char *nptr, char **endptr)
else
{
/*
* Try again. errno is already 0 here.
* Try again. errno is already 0 here, and we assume that the endptr
* won't be any different.
*/
double dresult = strtod(nptr, NULL);