postgres.git / summary / log / commit / refs
commit 9b136b0f2e531e41d1949fba3f618405adfcef02
Author: Thomas Munro <tmunro@postgresql.org>
Commit: Andrew Dunstan <andrew@dunslane.net>
Date: Tue Oct 25 02:21:42 2022 +0000
First released in: 13.19, 14.16, 15.11
Fix readlink() for non-PostgreSQL junction points on Windows.
Since commit c5cb8f3b taught stat() to follow symlinks, and since initdb
uses pg_mkdir_p(), and that examines parent directories, our humble
readlink() implementation can now be exposed to junction points not of
PostgreSQL origin. Those might be corrupted by our naive path mangling,
which doesn't really understand NT paths in general.
Simply decline to transform paths that don't look like a drive absolute
path. That means that readlink() returns the NT path directly when
checking a parent directory of PGDATA that happen to point to a drive
using "rooted" format. That works for the purposes of our stat()
emulation.
Reported-by: Roman Zharkov <r.zharkov@postgrespro.ru>
Reviewed-by: Roman Zharkov <r.zharkov@postgrespro.ru>
Discussion: https://postgr.es/m/4590c37927d7b8ee84f9855d83229018%40postgrespro.ru
Discussion: https://postgr.es/m/CA%2BhUKG%2BajSQ_8eu2AogTncOnZ5me2D-Cn66iN_-wZnRjLN%2Bicg%40mail.gmail.com
Backpatched commit f71007fb as above by Thomas Munro into releases 13 thru 15
Discussion: https://postgr.es/m/CA+hUKGLbnv+pe3q1fYOVkLD3pMra7GuihfMxUN-1831YH9RYQg@mail.gmail.com
src/port/dirmod.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/src/port/dirmod.c b/src/port/dirmod.c
index 2818bfd2e95..7c80758a038 100644
--- a/src/port/dirmod.c
+++ b/src/port/dirmod.c
@@ -351,10 +351,21 @@ pgreadlink(const char *path, char *buf, size_t size)
}
/*
- * If the path starts with "\??\", which it will do in most (all?) cases,
- * strip those out.
+ * If the path starts with "\??\" followed by a "drive absolute" path
+ * (known to Windows APIs as RtlPathTypeDriveAbsolute), then strip that
+ * prefix. This undoes some of the transformation performed by
+ * pqsymlink(), to get back to a format that users are used to seeing. We
+ * don't know how to transform other path types that might be encountered
+ * outside PGDATA, so we just return them directly.
*/
- if (r > 4 && strncmp(buf, "\\??\\", 4) == 0)
+ if (r >= 7 &&
+ buf[0] == '\\' &&
+ buf[1] == '?' &&
+ buf[2] == '?' &&
+ buf[3] == '\\' &&
+ isalpha(buf[4]) &&
+ buf[5] == ':' &&
+ buf[6] == '\\')
{
memmove(buf, buf + 4, strlen(buf + 4) + 1);
r -= 4;
[parent: e708f31881fd]