[PATCH v2 09/16] gdb.mi/mi-logging.exp, don't send input to GDB while the inferior is running

[Pedro Alves <pedro@palves.net>]

The gdb.mi/mi-logging.exp testcase sends a sequence of execution
commands to the GDB terminal while the inferior is running, like this:

 send_gdb "1002-exec-step\n"
 send_gdb "1003-exec-next\n"

expecting that GDB will consume the "1003-exec-next" intput after the
inferior stops for the 1002-exec-step.

That's a flawed assumption in general, because the inferior itself
could consume the "1003-exec-next" input while it is stepping.

When GDB puts the inferior in its own terminal, while the inferior is
running, GDB marshals input from its terminal to the inferior's
terminal.  The result is that input typed while the inferior is
running never goes to GDB, and so the test fails.

The previous patch addressed issues like this by making the inferior
and GDB share the same terminal for tests that really wanted to test
some aspect of a shared terminal.  For gdb.mi/mi-logging.exp though,
there's really no reason to send input while the program is running,
so the fix here is to stop it from doing so.

While debugging the testcase, I ran into the fact that it reuses the
same log file for more than one [open] sequence, overwriting previous
runs.  The testcase also deletes the log files at the very end, which
makes it impossible to inspect the logs after a failure run.  The
patch addresses those issues as well.

gdb/testsuite/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	* gdb.mi/mi-logging.exp: Do not reuse log files for different
	runs.  Delete logs at the start of the testcase, not at the
	end.
	(wait_open, gdb_test_file): New procedures.  Use them.

Change-Id: Ife215a82391a020041fd05478bd8dbee6e04d607
---
 gdb/testsuite/gdb.mi/mi-logging.exp | 94 +++++++++++++++++++++++------
 1 file changed, 77 insertions(+), 17 deletions(-)

diff --git a/gdb/testsuite/gdb.mi/mi-logging.exp b/gdb/testsuite/gdb.mi/mi-logging.exp
index ff47b0849c0..d50eaee22c8 100644
--- a/gdb/testsuite/gdb.mi/mi-logging.exp
+++ b/gdb/testsuite/gdb.mi/mi-logging.exp
@@ -30,9 +30,13 @@ if {[mi_runto_main] < 0} {
     return -1
 }
 
-set milogfile [standard_output_file "milog.txt"]
+set milogfile1 [standard_output_file "milog1.txt"]
+set milogfile2 [standard_output_file "milog2.txt"]
 
-mi_gdb_test "-gdb-set logging file $milogfile" ".*"
+remote_file host delete $milogfile1
+remote_file host delete $milogfile2
+
+mi_gdb_test "-gdb-set logging file $milogfile1" ".*"
 
 mi_gdb_test "-gdb-set logging overwrite on" ".*"
 
@@ -44,7 +48,7 @@ mi_next "logged next"
 
 mi_gdb_test "-gdb-set logging off" ".*" "logging off"
 
-set chan [open $milogfile]
+set chan [open $milogfile1]
 set logcontent [read $chan]
 close $chan
 
@@ -58,26 +62,84 @@ if [regexp "\\^done\[\r\n\]+$mi_log_prompt\\^running\[\r\n\]+\\*running,thread-i
 
 # Now try the redirect, which writes into the file only.
 
-mi_gdb_test "-gdb-set logging redirect on" ".*" "redirect logging on"
+mi_gdb_test "-gdb-set logging file $milogfile2" ".*"
 
-# Since all output will be going into the file, just keep sending commands
-# and don't expect anything to appear until logging is turned off.
+mi_gdb_test "999-gdb-set logging redirect on" ".*" "redirect logging on"
 
 send_gdb "1001-gdb-set logging on\n"
+
+# We can't open the file right away, because we're not waiting for
+# GDB's "^done" -- we could end up opening the file before GDB creates
+# it.  So spin waiting until the file exists.
+
+proc wait_open {filename} {
+    set ticks [expr 10 * $::timeout]
+    set t 0
+
+    while {![file exists $filename]} {
+	after 100
+
+	incr t
+	if {$t == $ticks} {
+	    return ""
+	}
+    }
+    return [open $filename]
+}
+
+set chan [wait_open $milogfile2]
+
+# Read GDB output in channel/file CHAN, expect the result.  PATTERN is
+# the pattern to match for a PASS.
+
+proc gdb_test_file {chan pattern test} {
+    global timeout
+
+    verbose -log "gdb_test_file: begin"
+
+    set ticks [expr 10 * $timeout]
+    set t 0
+    set logcontent ""
+
+    while {1} {
+	set r [read $chan]
+	append logcontent $r
+
+	send_log -- "$r"
+
+	if [regexp "$pattern" $logcontent] {
+	    pass "$test"
+	    break
+	} else {
+	    incr t
+	    if {$t == $ticks} {
+		fail "$test (timeout)"
+		break
+	    }
+	    after 100
+	}
+    }
+
+    verbose -log "gdb_test_file: end"
+}
+
+gdb_test_file $chan \
+    "1001\\^done\[\r\n\]+$mi_log_prompt" \
+    "redirect log file contents, set logging on"
+
 send_gdb "1002-exec-step\n"
-send_gdb "1003-exec-next\n"
+gdb_test_file $chan \
+    "1002\\^running\[\r\n\]+\\*running,thread-id=\"all\"\[\r\n\]+$mi_log_prompt\\*stopped,reason=\"end-stepping-range\",.*\[\r\n\]+$mi_log_prompt" \
+    "redirect log file contents, exec-step"
 
-mi_gdb_test "1004-gdb-set logging off" ".*" "redirect logging off"
+send_gdb "1003-exec-next\n"
+gdb_test_file $chan \
+    "1003\\^running\[\r\n\]+\\*running,thread-id=\"all\"\[\r\n\]+$mi_log_prompt\\*stopped,reason=\"end-stepping-range\",.*\[\r\n\]+$mi_log_prompt" \
+    "redirect log file contents, exec-next"
 
-set chan [open $milogfile]
-set logcontent [read $chan]
 close $chan
 
-if [regexp "1001\\^done\[\r\n\]+$mi_log_prompt.*1002\\^running\[\r\n\]+\\*running,thread-id=\"all\"\[\r\n\]+$mi_log_prompt\\*stopped,reason=\"end-stepping-range\",.*\[\r\n\]+$mi_log_prompt.*1003\\^running\[\r\n\]+\\*running,thread-id=\"all\"\[\r\n\]+$mi_log_prompt\\*stopped,reason=\"end-stepping-range\",.*\[\r\n\]+$mi_log_prompt" $logcontent] {
-    pass "redirect log file contents"
-} else {
-    fail "redirect log file contents"
-}
+mi_gdb_test "1004-gdb-set logging off" ".*" "redirect logging off"
 
 # Now try enabling a redirect while GDB is already logging.  This used
 # to crash GDB.
@@ -94,5 +156,3 @@ with_test_prefix "redirect while already logging" {
 }
 
 mi_gdb_exit
-
-remote_file host delete $milogfile
-- 
2.26.2