Use STDOUT/STDERR_FILENO in most of syslogger.

This fixes problems on windows when logging collector is used in a service,
failing with:
FATAL:  could not redirect stderr: Bad file descriptor

This is triggered by 76e38b37a5. The problem is that STDOUT/STDERR_FILENO
aren't defined on windows, which lead us to use _fileno(stdout) etc, but that
doesn't work if stdout/stderr are closed.

Author: Andres Freund <andres@anarazel.de>
Reported-By: Sandeep Thakkar <sandeep.thakkar@enterprisedb.com>
Message-Id: 20220520164558.ozb7lm6unakqzezi@alap3.anarazel.de (on pgsql-packagers)
Backpatch: 15-, where 76e38b37a5 came in

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 25e2131e31180b8e6a573b31399692a08e780103..d6d02e3c6363514209ac7f3151dc064080252e46 100644 (file)
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -205,12 +205,12 @@ SysLoggerMain(int argc, char *argv[])
                 * if they fail then presumably the file descriptors are closed and
                 * any writes will go into the bitbucket anyway.
                 */
-               close(fileno(stdout));
-               close(fileno(stderr));
+               close(STDOUT_FILENO);
+               close(STDERR_FILENO);
                if (fd != -1)
                {
-                       (void) dup2(fd, fileno(stdout));
-                       (void) dup2(fd, fileno(stderr));
+                       (void) dup2(fd, STDOUT_FILENO);
+                       (void) dup2(fd, STDERR_FILENO);
                        close(fd);
                }
        }
@@ -222,7 +222,7 @@ SysLoggerMain(int argc, char *argv[])
         */
 #ifdef WIN32
        else
-               _setmode(_fileno(stderr), _O_TEXT);
+               _setmode(STDERR_FILENO, _O_TEXT);
 #endif
 
        /*
@@ -716,12 +716,12 @@ SysLogger_Start(void)
 
 #ifndef WIN32
                                fflush(stdout);
-                               if (dup2(syslogPipe[1], fileno(stdout)) < 0)
+                               if (dup2(syslogPipe[1], STDOUT_FILENO) < 0)
                                        ereport(FATAL,
                                                        (errcode_for_file_access(),
                                                         errmsg("could not redirect stdout: %m")));
                                fflush(stderr);
-                               if (dup2(syslogPipe[1], fileno(stderr)) < 0)
+                               if (dup2(syslogPipe[1], STDERR_FILENO) < 0)
                                        ereport(FATAL,
                                                        (errcode_for_file_access(),
                                                         errmsg("could not redirect stderr: %m")));
@@ -738,12 +738,12 @@ SysLogger_Start(void)
                                fflush(stderr);
                                fd = _open_osfhandle((intptr_t) syslogPipe[1],
                                                                         _O_APPEND | _O_BINARY);
-                               if (dup2(fd, _fileno(stderr)) < 0)
+                               if (dup2(fd, STDERR_FILENO) < 0)
                                        ereport(FATAL,
                                                        (errcode_for_file_access(),
                                                         errmsg("could not redirect stderr: %m")));
                                close(fd);
-                               _setmode(_fileno(stderr), _O_BINARY);
+                               _setmode(STDERR_FILENO, _O_BINARY);
 
                                /*
                                 * Now we are done with the write end of the pipe.