Fix readlink() return value on Windows.

macdice · macdice · commit 4650036f5ab8 · 2022-10-25T15:13:52.000+13:00
Ancient bug noticed while working on a test suite for these functions. Discussion: https://postgr.es/m/CA%2BhUKG%2BajSQ_8eu2AogTncOnZ5me2D-Cn66iN_-wZnRjLN%2Bicg%40mail.gmail.com
diff --git a/src/port/dirmod.c b/src/port/dirmod.c
@@ -359,6 +359,9 @@ pgreadlink(const char *path, char *buf, size_t size)
 		return -1;
 	}
 
+	/* r includes the null terminator */
+	r -= 1;
+
 	/*
 	 * If the path starts with "\??\", which it will do in most (all?) cases,
 	 * strip those out.

Original file line number	Diff line number	Diff line change
`@@ -359,6 +359,9 @@ pgreadlink(const char path, char buf, size_t size)`
`359`	`359`	`return -1;`
`360`	`360`	`}`
`361`	`361`
	`362`	`+ /* r includes the null terminator */`
	`363`	`+ r -= 1;`
	`364`	`+`
`362`	`365`	`/*`
`363`	`366`	`* If the path starts with "\??\", which it will do in most (all?) cases,`
`364`	`367`	`* strip those out.`