From: Daniel Watzinger <daniel.watzinger@gmail.com>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: pgsql-hackers@postgresql.org
Subject: pg_dump/pg_restore: Fix stdin/stdout handling of custom format on
 Win32
Date: Sat, 17 Dec 2022 00:55:24 +0100
Message-Id: <20221216235524.8483-1-daniel.watzinger@gmail.com>
In-Reply-To: <0F43E234-48F2-4C99-BCBE-6C41F053C666@yesql.se>
References: <0F43E234-48F2-4C99-BCBE-6C41F053C666@yesql.se>
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--------------2.39.0.windows.1
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Well, this is embarassing. Sorry for the inconvenience. Some part
of my company's network infrastruture must have mangled the attachment.
Both mails were sent using a combination of git format-patch 
and git send-email. However, as this is my first foray into this 
email-based workflow, I won't rule out a failure on my part. Bear
with me and let's try again. 
--------------2.39.0.windows.1
Content-Type: text/x-patch;
 name="v1-0001-pg_dump-pg_restore-Fix-stdin-stdout-handling-of-c.patch"
Content-Transfer-Encoding: 8bit
Content-Disposition: attachment;
 filename="v1-0001-pg_dump-pg_restore-Fix-stdin-stdout-handling-of-c.patch"

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 7f7a0f1ce7..684db4a17a 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -3838,6 +3838,18 @@ bool
 checkSeek(FILE *fp)
 {
 	pgoff_t		tpos;
+	struct stat	st;
+
+	/* Check if this is a terminal descriptor */
+	if (isatty(fileno(fp))) {
+		return false;
+	}
+
+	/* Check if this is an unseekable character special device or pipe */
+	if ((fstat(fileno(fp), &st) == 0) && (S_ISCHR(st.st_mode)
+		|| S_ISFIFO(st.st_mode))) {
+		return false;
+	}
 
 	/* Check that ftello works on this file */
 	tpos = ftello(fp);
diff --git a/src/include/port/win32_port.h b/src/include/port/win32_port.h
index 296905bc6c..892d0bb401 100644
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -329,6 +329,12 @@ extern int	_pglstat64(const char *name, struct stat *buf);
 #ifndef S_ISREG
 #define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
 #endif
+#ifndef S_ISFIFO
+#define S_ISFIFO(m) (((m) & S_IFMT) == _S_IFIFO)
+#endif
+#ifndef S_ISCHR
+#define S_ISCHR(m) (((m) & S_IFMT) == S_IFCHR)
+#endif
 
 /*
  * In order for lstat() to be able to report junction points as symlinks, we
diff --git a/src/port/win32stat.c b/src/port/win32stat.c
index e6553e4030..7ab0983a74 100644
--- a/src/port/win32stat.c
+++ b/src/port/win32stat.c
@@ -256,35 +256,65 @@ _pgstat64(const char *name, struct stat *buf)
 int
 _pgfstat64(int fileno, struct stat *buf)
 {
-	HANDLE		hFile = (HANDLE) _get_osfhandle(fileno);
-	BY_HANDLE_FILE_INFORMATION fiData;
+	HANDLE			hFile = (HANDLE) _get_osfhandle(fileno);
+	DWORD			fileType = FILE_TYPE_UNKNOWN;
+	DWORD			lastError;
+	unsigned short	st_mode;
 
-	if (hFile == INVALID_HANDLE_VALUE || buf == NULL)
+	if (hFile == INVALID_HANDLE_VALUE || hFile == (HANDLE)-2 || buf == NULL)
 	{
 		errno = EINVAL;
 		return -1;
 	}
 
-	/*
-	 * Check if the fileno is a data stream.  If so, unless it has been
-	 * redirected to a file, getting information through its HANDLE will fail,
-	 * so emulate its stat information in the most appropriate way and return
-	 * it instead.
+	fileType = GetFileType(hFile);
+	lastError = GetLastError();
+
+	/* 
+	 * Invoke GetLastError in order to distinguish between a "valid"
+	 * return of FILE_TYPE_UNKNOWN and its return due to a calling error.
+	 * In case of success, GetLastError returns NO_ERROR.
 	 */
-	if ((fileno == _fileno(stdin) ||
-		 fileno == _fileno(stdout) ||
-		 fileno == _fileno(stderr)) &&
-		!GetFileInformationByHandle(hFile, &fiData))
+	if (fileType == FILE_TYPE_UNKNOWN && lastError != NO_ERROR) {
+		_dosmaperr(lastError);
+		return -1;
+	}
+
+	switch (fileType)
 	{
-		memset(buf, 0, sizeof(*buf));
-		buf->st_mode = _S_IFCHR;
-		buf->st_dev = fileno;
-		buf->st_rdev = fileno;
-		buf->st_nlink = 1;
-		return 0;
+		/* The specified file is a disk file */
+		case FILE_TYPE_DISK:
+			return fileinfo_to_stat(hFile, buf);
+		/*
+		 * The specified file is a socket,
+		 * a named pipe, or an anonymous pipe.
+		 */
+		case FILE_TYPE_PIPE:
+			st_mode = _S_IFIFO;
+			break;
+		/* 
+		 * The specified file is a character file,
+		 * typically an LPT device or a console
+		 */
+		case FILE_TYPE_CHAR:
+		/* 
+		 * Unused flag and unknown file type
+		 */
+		case FILE_TYPE_REMOTE:
+		case FILE_TYPE_UNKNOWN:
+			st_mode = _S_IFCHR;
+			break;
+		default:
+			errno = EINVAL;
+			return -1;
 	}
 
-	return fileinfo_to_stat(hFile, buf);
+	memset(buf, 0, sizeof(*buf));
+	buf->st_mode = st_mode;
+	buf->st_dev = fileno;
+	buf->st_rdev = fileno;
+	buf->st_nlink = 1;
+	return 0;
 }
 
 #endif							/* WIN32 */

base-commit: e52f8b301ed54aac5162b185b43f5f1e44b6b17e

--------------2.39.0.windows.1--