| # Copyright 2022-2024 Free Software Foundation, Inc. |
| |
| # This program is free software; you can redistribute it and/or modify |
| # it under the terms of the GNU General Public License as published by |
| # the Free Software Foundation; either version 3 of the License, or |
| # (at your option) any later version. |
| # |
| # This program is distributed in the hope that it will be useful, |
| # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| # GNU General Public License for more details. |
| # |
| # You should have received a copy of the GNU General Public License |
| # along with this program. If not, see <http://www.gnu.org/licenses/>. |
| |
| # In the past we would use glibc's buffered input for the mi tty. |
| # This buffering would cause problems if two commands are sent to gdb |
| # in a single write call, and, if the first command (excluding its |
| # trailing newline) exactly filled glibc's internal buffer. |
| # |
| # The solution to this problem was to stop using glibc's buffering for |
| # the mi tty. |
| # |
| # To test for this situation we send two command to gdb in a loop, the |
| # first command gets progressively bigger. We check that gdb |
| # correctly sees both commands. |
| |
| load_lib mi-support.exp |
| set MIFLAGS "-i=mi" |
| |
| # Start gdb, passing ARGS to mi_gdb_start. Then run a series of tests |
| # passing two commands to gdb in a single write action. The first |
| # command is increasingly long, while the second command stays very |
| # short. |
| # |
| # Check that gdb sees, and performs, both commands. |
| proc run_test { args } { |
| global mi_gdb_prompt |
| global decimal |
| |
| if [mi_clean_restart "" $args] { |
| return |
| } |
| |
| set start 1 |
| set limit 2049 |
| |
| mi_gdb_test "set \$a = \"FIRST COMMAND\"" ".*" |
| mi_gdb_test "set \$b = \"TEST COMPLETE\"" ".*" |
| |
| for { set i $start } { $i < $limit } { incr i } { |
| |
| set cmd "" |
| |
| # Create a command that is at least `i` characters long. |
| set first_cmd "-data-evaluate-expression \$a" |
| while { [string length $first_cmd] < $i } { |
| set first_cmd " $first_cmd" |
| } |
| |
| # We reset `i`, our loop counter, here. When i is large this |
| # should be a nop as we attempt to make the first command |
| # length be i above. However, the first time around the loop |
| # we start with an i value of 1, however, we can't make a |
| # command that short, so, by resetting i here we effectively |
| # skip the first couple of loop iterations where i is less |
| # than the minimum command length. |
| set i [string length $first_cmd] |
| verbose -log "length of first command is $i" |
| |
| set cmd "${first_cmd}\n-data-evaluate-expression \$b\n" |
| |
| # We need to call send_gdb ourselves here as gdb_test_multiple |
| # will try to send each line of the command separately (breaking |
| # the command at newline characters). This splitting will more |
| # than likely mean that gdb will see and process the first command |
| # before the second command arrives, this prevents the bug from |
| # triggering. |
| send_gdb "$cmd" |
| |
| # Now check for output from the two commands. We do this |
| # using two calls to gdb_test_multiple, this is because the |
| # echoing of the second command can sometime get mixed |
| # unexpectedly with the command output, this is especially |
| # likely when running using the read1 technique. |
| # |
| # When using a single gdb_test_multiple we need to anchor |
| # patterns using a ^, however, this requires us to consume and |
| # discard all lines that are not part of the output that we're |
| # looking for. However, due to the unpredictable |
| # intermingling, it's much easier if we drop the ^ anchor. |
| # However, with this gone dejagnu would sometimes match the |
| # second comand output before the first commands output. |
| # |
| # This approach just looks for the first command output, then, |
| # once that has been found, we start looking for the second |
| # command output, this seems pretty reliable. |
| set seen_first_message false |
| set seen_second_message false |
| |
| gdb_test_multiple "" "look for first command output, command length $i" -prompt "$mi_gdb_prompt" { |
| -re "\\^done.*,value=\"\\\\\"FIRST COMMAND\\\\\"\"" { |
| set seen_first_message true |
| exp_continue |
| } |
| -re "\r\n$mi_gdb_prompt" { |
| gdb_assert $seen_first_message $gdb_test_name |
| } |
| } |
| |
| gdb_test_multiple "" "look for second command output, command length $i" -prompt "$mi_gdb_prompt" { |
| -re "\\^done,value=\"\\\\\"TEST COMPLETE\\\\\"\"\r\n$mi_gdb_prompt" { |
| pass $gdb_test_name |
| set seen_second_message true |
| } |
| } |
| |
| # If one of the above tests failed then lets no waste our time |
| # checking different command lengths. The actual bug this |
| # test checks for would result in a timeout, so we don't want |
| # to risk lots more timeouts. |
| if { ! [expr $seen_first_message && $seen_second_message ] } { |
| break |
| } |
| } |
| } |
| |
| foreach_with_prefix args { "" "separate-mi-tty" } { |
| run_test $args |
| } |