postgres.git / summary / log / commit / refs

commit    8a5e4982f9c536fafa4ae9b7c331ee656ded2fe5
Author:   Thomas Munro <tmunro@postgresql.org>
Commit:   Andrew Dunstan <andrew@dunslane.net>
Date:     Tue Oct 25 02:20:00 2022 +0000

    Fix lstat() for broken junction points on Windows.
    
    When using junction points to emulate symlinks on Windows, one edge case
    was not handled correctly by commit c5cb8f3b: if a junction point is
    broken (pointing to a non-existent path), we'd report ENOENT.  This
    doesn't break any known use case, but was noticed while developing a
    test suite for these functions and is fixed here for completeness.
    
    Also add translation ERROR_CANT_RESOLVE_FILENAME -> ENOENT, as that is
    one of the errors Windows can report for some kinds of broken paths.
    
    Discussion: https://postgr.es/m/CA%2BhUKG%2BajSQ_8eu2AogTncOnZ5me2D-Cn66iN_-wZnRjLN%2Bicg%40mail.gmail.com
    (cherry picked from commit 387803d81d6256fcb60b9192bb5b00042442b4e3)
    
    Author: Thomas Munro <tmunro@postgresql.org>
    Author: Alexandra Wang <alexandra.wang.oss@gmail.com>


 src/port/win32error.c |  6 ++++++
 src/port/win32stat.c  | 27 ++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/port/win32error.c b/src/port/win32error.c
index 0e5f91adfa0..60253d1e3f3 100644
--- a/src/port/win32error.c
+++ b/src/port/win32error.c
@@ -164,6 +164,12 @@ static const struct
 	},
 	{
 		ERROR_DELETE_PENDING, ENOENT
+	},
+	{
+		ERROR_INVALID_NAME, ENOENT
+	},
+	{
+		ERROR_CANT_RESOLVE_FILENAME, ENOENT
 	}
 };
 
diff --git a/src/port/win32stat.c b/src/port/win32stat.c
index 001e329a18d..49fbb3ce649 100644
--- a/src/port/win32stat.c
+++ b/src/port/win32stat.c
@@ -127,15 +127,30 @@ _pglstat64(const char *name, struct stat *buf)
 
 	hFile = pgwin32_open_handle(name, O_RDONLY, true);
 	if (hFile == INVALID_HANDLE_VALUE)
-		return -1;
-
-	ret = fileinfo_to_stat(hFile, buf);
+	{
+		if (errno == ENOENT)
+		{
+			/*
+			 * If it's a junction point pointing to a non-existent path, we'll
+			 * have ENOENT here (because pgwin32_open_handle does not use
+			 * FILE_FLAG_OPEN_REPARSE_POINT).  In that case, we'll try again
+			 * with readlink() below, which will distinguish true ENOENT from
+			 * pseudo-symlink.
+			 */
+			memset(buf, 0, sizeof(*buf));
+			ret = 0;
+		}
+		else
+			return -1;
+	}
+	else
+		ret = fileinfo_to_stat(hFile, buf);
 
 	/*
 	 * Junction points appear as directories to fileinfo_to_stat(), so we'll
 	 * need to do a bit more work to distinguish them.
 	 */
-	if (ret == 0 && S_ISDIR(buf->st_mode))
+	if ((ret == 0 && S_ISDIR(buf->st_mode)) || hFile == INVALID_HANDLE_VALUE)
 	{
 		char		next[MAXPGPATH];
 		ssize_t		size;
@@ -171,10 +186,12 @@ _pglstat64(const char *name, struct stat *buf)
 			buf->st_mode &= ~S_IFDIR;
 			buf->st_mode |= S_IFLNK;
 			buf->st_size = size;
+			ret = 0;
 		}
 	}
 
-	CloseHandle(hFile);
+	if (hFile != INVALID_HANDLE_VALUE)
+		CloseHandle(hFile);
 	return ret;
 }
 


[parent: 895f23d9e174]