script: add more info to script header

This patch introduces [...] to store extra information about terminal
to the typescript header. For example:

  Script started on 2018-05-14 12:52:32+02:00 [TERM="xterm-256color" TTY="/dev/pts/3" COLS="190" LINES="53"]

or

  Script started on 2018-05-14 12:54:01+02:00 [<not executed on terminal>]

if stdout is not terminal.

Addresses: https://github.com/karelzak/util-linux/issues/583
Signed-off-by: Karel Zak <kzak@redhat.com>

Documentation/TODO

@@ -15,12 +15,6 @@ column
 
 script
 ------
-   - (!) add terminal type ($TERM), columns and lines to the header line, something like:
-
-		Script started on 2018-03-05 13:02:08+0100 [term="xterm-256color", lines=53, columns=190]
-
-     see https://github.com/karelzak/util-linux/issues/583
-
    - (!) add [exit=<command-exit-code>] to the "done" typescript message
 
    - think about optional "event" records in timing file to save information

include/ttyutils.h

@@ -52,6 +52,7 @@ struct chardata {
 
 extern int get_terminal_dimension(int *cols, int *lines);
 extern int get_terminal_width(int default_width);
+extern int get_terminal_type(const char **type);
 extern int get_terminal_name(const char **path, const char **name,
 			     const char **number);
 

lib/ttyutils.c

@@ -113,6 +113,13 @@ int get_terminal_name(const char **path,
 	return 0;
 }
 
+int get_terminal_type(const char **type)
+{
+	*type = getenv("TERM");
+	if (*type)
+		return -EINVAL;
+	return 0;
+}
 
 #ifdef TEST_PROGRAM_TTYUTILS
 # include <stdlib.h>

term-utils/script.c

@@ -182,6 +182,36 @@ static void __attribute__((__noreturn__)) usage(void)
 	exit(EXIT_SUCCESS);
 }
 
+static void typescript_message_start(const struct script_control *ctl, time_t *tvec)
+{
+	char buf[FORMAT_TIMESTAMP_MAX];
+	int cols = 0, lines = 0;
+	const char *tty = NULL, *term = NULL;
+
+	if (!ctl->typescriptfp)
+		return;
+
+	strtime_iso(tvec, ISO_TIMESTAMP, buf, sizeof(buf));
+
+	fprintf(ctl->typescriptfp, _("Script started on %s ["), buf);
+
+	if (ctl->isterm) {
+		get_terminal_dimension(&cols, &lines);
+		get_terminal_name(&tty, NULL, NULL);
+		get_terminal_type(&term);
+
+		if (term)
+			fprintf(ctl->typescriptfp, "TERM=\"%s\" ", term);
+		if (tty)
+			fprintf(ctl->typescriptfp, "TTY=\"%s\" ", tty);
+
+		fprintf(ctl->typescriptfp, "COLS=\"%d\" LINES=\"%d\"", cols, lines);
+	} else
+		fprintf(ctl->typescriptfp, _("<not executed on terminal>"));
+
+	fputs("]\n", ctl->typescriptfp);
+}
+
 static void die_if_link(const struct script_control *ctl)
 {
 	struct stat s;
@@ -496,11 +526,9 @@ static void do_io(struct script_control *ctl)
 	}
 
 
-	if (ctl->typescriptfp) {
-		char buf[FORMAT_TIMESTAMP_MAX];
-		strtime_iso(&tvec, ISO_TIMESTAMP, buf, sizeof(buf));
-		fprintf(ctl->typescriptfp, _("Script started on %s\n"), buf);
-	}
+	if (ctl->typescriptfp)
+		typescript_message_start(ctl, &tvec);
+
 	gettime_monotonic(&ctl->oldtime);
 
 	while (!ctl->die) {