From ebe919e95336cbe0a0b5078189e1525bfb038385 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 1 Mar 2025 14:22:56 -0500
Subject: [PATCH] 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
---
src/port/strtof.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/src/port/strtof.c b/src/port/strtof.c
index 2a5553bc5fe..acd833267a0 100644
--- a/src/port/strtof.c
+++ b/src/port/strtof.c
@@ -76,15 +76,18 @@ 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)))
{
/*
@@ -98,7 +101,8 @@ 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);
--
2.39.5