Fixes #45790: wget prints it's progress even when background

* src/log.c: Use tcgetpgrp(STDIN_FILENO) != getpgrp() to determine when to print to STD* or logfile.
  Deprecate log_request_redirect_output function.
  Use different file handles for STD* and logfile, to easily switch between them when changing fg/bg.
* src/log.h: Make redirect_output function externally linked.
* src/main.c: Don't use deprecated log_request_redirect_output function. Use redirect_output instead.
* src/mswindows.c: Don't use deprecated log_request_redirect_output function. Use redirect_output instead.

4 files changed, 85 insertions, 48 deletions

diff --git a/src/log.c b/src/log.c
index a1338cac..e122238c 100644
--- a/src/log.c
+++ b/src/log.c
@@ -80,6 +80,18 @@ as that of the covered work.  */
    logging is inhibited, logfp is set back to NULL. */
 static FILE *logfp;
 
+/* Descriptor of the stdout|stderr */
+static FILE *stdlogfp;
+
+/* Descriptor of the wget.log* file (if created) */
+static FILE *filelogfp;
+
+/* Name of log file */
+static char *logfile;
+
+/* Is interactive shell ? */
+static int shell_is_interactive;
+
 /* A second file descriptor pointing to the temporary log file for the
    WARC writer.  If WARC writing is disabled, this is NULL.  */
 static FILE *warclogfp;
@@ -611,16 +623,18 @@ log_init (const char *file, bool appendp)
     {
       if (HYPHENP (file))
         {
-          logfp = stdout;
+          stdlogfp = stdout;
+          logfp = stdlogfp;
         }
       else
         {
-          logfp = fopen (file, appendp ? "a" : "w");
-          if (!logfp)
+          filelogfp = fopen (file, appendp ? "a" : "w");
+          if (!filelogfp)
             {
               fprintf (stderr, "%s: %s: %s\n", exec_name, file, strerror (errno));
               exit (WGET_EXIT_GENERIC_ERROR);
             }
+          logfp = filelogfp;
         }
     }
   else
@@ -631,7 +645,8 @@ log_init (const char *file, bool appendp)
          stderr only if the user actually specifies `-O -'.  He says
          this inconsistency is harder to document, but is overall
          easier on the user.  */
-      logfp = stderr;
+      stdlogfp = stderr;
+      logfp = stdlogfp;
 
       if (1
 #ifdef HAVE_ISATTY
@@ -646,6 +661,11 @@ log_init (const char *file, bool appendp)
           save_context_p = true;
         }
     }
+
+#ifndef WINDOWS
+  /* Initialize this values so we don't have to ask every time we print line */
+  shell_is_interactive = isatty (STDIN_FILENO);
+#endif
 }
 
 /* Close LOGFP (only if we opened it, not if it's stderr), inhibit
@@ -880,59 +900,78 @@ log_cleanup (void)
 
 /* When SIGHUP or SIGUSR1 are received, the output is redirected
    elsewhere.  Such redirection is only allowed once. */
-static enum { RR_NONE, RR_REQUESTED, RR_DONE } redirect_request = RR_NONE;
 static const char *redirect_request_signal_name;
 
-/* Redirect output to `wget-log'.  */
+/* Redirect output to `wget-log' or back to stdout/stderr.  */
 
-static void
-redirect_output (void)
+void
+redirect_output (bool to_file, const char *signal_name)
 {
-  char *logfile;
-  logfp = unique_create (DEFAULT_LOGFILE, false, &logfile);
-  if (logfp)
+  if (to_file && logfp != filelogfp)
     {
-      fprintf (stderr, _("\n%s received, redirecting output to %s.\n"),
-               redirect_request_signal_name, quote (logfile));
-      xfree (logfile);
-      /* Dump the context output to the newly opened log.  */
-      log_dump_context ();
+      if (signal_name)
+        {
+          fprintf (stderr, "\n%s received.", signal_name);
+        }
+      if (!filelogfp)
+        {
+          filelogfp = unique_create (DEFAULT_LOGFILE, false, &logfile);
+          if (filelogfp)
+            {
+              fprintf (stderr, _("\nRedirecting output to %s.\n"),
+                  quote (logfile));
+              /* Store signal name to tell wget it's permanent redirect to log file */
+              redirect_request_signal_name = signal_name;
+              logfp = filelogfp;
+              /* Dump the context output to the newly opened log.  */
+              log_dump_context ();
+            }
+          else
+            {
+              /* Eek!  Opening the alternate log file has failed.  Nothing we
+                can do but disable printing completely. */
+              fprintf (stderr, _("%s: %s; disabling logging.\n"),
+                      (logfile) ? logfile : DEFAULT_LOGFILE, strerror (errno));
+              inhibit_logging = true;
+            }
+        }
+      else
+        {
+          fprintf (stderr, _("\nRedirecting output to %s.\n"),
+              quote (logfile));
+          logfp = filelogfp;
+          log_dump_context ();
+        }
     }
-  else
+  else if (!to_file && logfp != stdlogfp)
     {
-      /* Eek!  Opening the alternate log file has failed.  Nothing we
-         can do but disable printing completely. */
-      fprintf (stderr, _("\n%s received.\n"), redirect_request_signal_name);
-      fprintf (stderr, _("%s: %s; disabling logging.\n"),
-               (logfile) ? logfile : DEFAULT_LOGFILE, strerror (errno));
-      inhibit_logging = true;
+      logfp = stdlogfp;
+      log_dump_context ();
     }
-  save_context_p = false;
 }
 
-/* Check whether a signal handler requested the output to be
-   redirected. */
+/* Check whether there's a need to redirect output. */
 
 static void
 check_redirect_output (void)
 {
-  if (redirect_request == RR_REQUESTED)
+#ifndef WINDOWS
+  /* If it was redirected already to log file by SIGHUP or SIGUSR1,
+   * it was permanent and since that redirect_request_signal_name is set.
+   * If there was no SIGHUP or SIGUSR1 and shell is interactive
+   * we check if process is fg or bg before every line is printed.*/
+  if (!redirect_request_signal_name && shell_is_interactive)
     {
-      redirect_request = RR_DONE;
-      redirect_output ();
+      if (tcgetpgrp (STDIN_FILENO) != getpgrp ())
+        {
+          // Process backgrounded
+          redirect_output (true,NULL);
+        }
+      else
+        {
+          // Process foregrounded
+          redirect_output (false,NULL);
+        }
     }
-}
-
-/* Request redirection at a convenient time.  This may be called from
-   a signal handler. */
-
-void
-log_request_redirect_output (const char *signal_name)
-{
-  if (redirect_request == RR_NONE && save_context_p)
-    /* Request output redirection.  The request will be processed by
-       check_redirect_output(), which is called from entry point log
-       functions. */
-    redirect_request = RR_REQUESTED;
-  redirect_request_signal_name = signal_name;
+#endif /* WINDOWS */
 }
diff --git a/src/log.h b/src/log.h
index 0ccc26d4..c3b7fec3 100644
--- a/src/log.h
+++ b/src/log.h
@@ -52,6 +52,7 @@ void log_init (const char *, bool);
 void log_close (void);
 void log_cleanup (void);
 void log_request_redirect_output (const char *);
+void redirect_output (bool, const char *);
 
 const char *escnonprint (const char *);
 const char *escnonprint_uri (const char *);
diff --git a/src/main.c b/src/main.c
index d48e3b26..c2c7853b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -132,7 +132,7 @@ redirect_output_signal (int sig)
     signal_name = "SIGUSR1";
 #endif
 
-  log_request_redirect_output (signal_name);
+  redirect_output (true,signal_name);
   progress_schedule_redirect ();
   signal (sig, redirect_output_signal);
 }
diff --git a/src/mswindows.c b/src/mswindows.c
index 9735370e..90e6ec4f 100644
--- a/src/mswindows.c
+++ b/src/mswindows.c
@@ -53,9 +53,6 @@ as that of the covered work.  */
 #endif
 
 
-/* Defined in log.c.  */
-void log_request_redirect_output (const char *);
-
 /* Windows version of xsleep in utils.c.  */
 
 void
@@ -98,7 +95,7 @@ static void
 ws_hangup (const char *reason)
 {
   fprintf (stderr, _("Continuing in background.\n"));
-  log_request_redirect_output (reason);
+  redirect_output (true, reason);
 
   /* Detach process from the current console.  Under Windows 9x, if we
      were launched from a 16-bit process (which is usually the case;