postgres.git / summary / log / commit / refs

commit    c7303f01c574c3543c68452c7dfd8998efe25085
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Sat Mar 01 19:22:56 2025 +0000
First released in: 18.0, 13.21, 14.18, 15.13, 16.9, 17.5

    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 7da05be687b..9ede9d297e6 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);
 


[parent: ec741d48036a]