| 1 | /* Notification to GDB. |
| 2 | Copyright (C) 1989-2015 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | /* Async notifications to GDB. When the state of remote target is |
| 20 | changed or something interesting to GDB happened, async |
| 21 | notifications are used to tell GDB. |
| 22 | |
| 23 | Each type of notification is represented by an object |
| 24 | 'struct notif_server', in which there is a queue for events to GDB |
| 25 | represented by 'struct notif_event'. GDBserver writes (by means of |
| 26 | 'write' field) each event in the queue into the buffer and send the |
| 27 | contents in buffer to GDB. The contents in buffer is specified in |
| 28 | RSP. See more in the comments to field 'queue' of |
| 29 | 'struct notif_server'. |
| 30 | |
| 31 | Here is the workflow of sending events and managing queue: |
| 32 | 1. At any time, when something interesting FOO happens, a object |
| 33 | of 'struct notif_event' or its sub-class EVENT is created for FOO. |
| 34 | |
| 35 | 2. Enque EVENT to the 'queue' field of 'struct notif_server' for |
| 36 | FOO and send corresponding notification packet to GDB if EVENT is |
| 37 | the first one. |
| 38 | #1 and #2 are done by function 'notif_push'. |
| 39 | |
| 40 | 3. EVENT is not deque'ed until the ack of FOO from GDB arrives. |
| 41 | Before ack of FOO arrives, FOO happens again, a new object of |
| 42 | EVENT is created and enque EVENT silently. |
| 43 | Once GDB has a chance to ack to FOO, it sends an ack to GDBserver, |
| 44 | and GDBserver repeatedly sends events to GDB and gets ack of FOO, |
| 45 | until queue is empty. Then, GDBserver sends 'OK' to GDB that all |
| 46 | queued notification events are done. |
| 47 | |
| 48 | # 3 is done by function 'handle_notif_ack'. */ |
| 49 | |
| 50 | #include "server.h" |
| 51 | #include "notif.h" |
| 52 | |
| 53 | static struct notif_server *notifs[] = |
| 54 | { |
| 55 | ¬if_stop, |
| 56 | }; |
| 57 | |
| 58 | /* Write another event or an OK, if there are no more left, to |
| 59 | OWN_BUF. */ |
| 60 | |
| 61 | void |
| 62 | notif_write_event (struct notif_server *notif, char *own_buf) |
| 63 | { |
| 64 | if (!QUEUE_is_empty (notif_event_p, notif->queue)) |
| 65 | { |
| 66 | struct notif_event *event |
| 67 | = QUEUE_peek (notif_event_p, notif->queue); |
| 68 | |
| 69 | notif->write (event, own_buf); |
| 70 | } |
| 71 | else |
| 72 | write_ok (own_buf); |
| 73 | } |
| 74 | |
| 75 | /* Handle the ack in buffer OWN_BUF,and packet length is PACKET_LEN. |
| 76 | Return 1 if the ack is handled, and return 0 if the contents |
| 77 | in OWN_BUF is not a ack. */ |
| 78 | |
| 79 | int |
| 80 | handle_notif_ack (char *own_buf, int packet_len) |
| 81 | { |
| 82 | size_t i; |
| 83 | struct notif_server *np; |
| 84 | |
| 85 | for (i = 0; i < ARRAY_SIZE (notifs); i++) |
| 86 | { |
| 87 | const char *ack_name = notifs[i]->ack_name; |
| 88 | |
| 89 | if (startswith (own_buf, ack_name) |
| 90 | && packet_len == strlen (ack_name)) |
| 91 | break; |
| 92 | } |
| 93 | |
| 94 | if (i == ARRAY_SIZE (notifs)) |
| 95 | return 0; |
| 96 | |
| 97 | np = notifs[i]; |
| 98 | |
| 99 | /* If we're waiting for GDB to acknowledge a pending event, |
| 100 | consider that done. */ |
| 101 | if (!QUEUE_is_empty (notif_event_p, np->queue)) |
| 102 | { |
| 103 | struct notif_event *head |
| 104 | = QUEUE_deque (notif_event_p, np->queue); |
| 105 | |
| 106 | if (remote_debug) |
| 107 | fprintf (stderr, "%s: acking %d\n", np->ack_name, |
| 108 | QUEUE_length (notif_event_p, np->queue)); |
| 109 | |
| 110 | xfree (head); |
| 111 | } |
| 112 | |
| 113 | notif_write_event (np, own_buf); |
| 114 | |
| 115 | return 1; |
| 116 | } |
| 117 | |
| 118 | /* Put EVENT to the queue of NOTIF. */ |
| 119 | |
| 120 | void |
| 121 | notif_event_enque (struct notif_server *notif, |
| 122 | struct notif_event *event) |
| 123 | { |
| 124 | QUEUE_enque (notif_event_p, notif->queue, event); |
| 125 | |
| 126 | if (remote_debug) |
| 127 | fprintf (stderr, "pending events: %s %d\n", notif->notif_name, |
| 128 | QUEUE_length (notif_event_p, notif->queue)); |
| 129 | |
| 130 | } |
| 131 | |
| 132 | /* Push one event NEW_EVENT of notification NP into NP->queue. */ |
| 133 | |
| 134 | void |
| 135 | notif_push (struct notif_server *np, struct notif_event *new_event) |
| 136 | { |
| 137 | int is_first_event = QUEUE_is_empty (notif_event_p, np->queue); |
| 138 | |
| 139 | /* Something interesting. Tell GDB about it. */ |
| 140 | notif_event_enque (np, new_event); |
| 141 | |
| 142 | /* If this is the first stop reply in the queue, then inform GDB |
| 143 | about it, by sending a corresponding notification. */ |
| 144 | if (is_first_event) |
| 145 | { |
| 146 | char buf[PBUFSIZ]; |
| 147 | char *p = buf; |
| 148 | |
| 149 | xsnprintf (p, PBUFSIZ, "%s:", np->notif_name); |
| 150 | p += strlen (p); |
| 151 | |
| 152 | np->write (new_event, p); |
| 153 | putpkt_notif (buf); |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | static void |
| 158 | notif_event_xfree (struct notif_event *event) |
| 159 | { |
| 160 | xfree (event); |
| 161 | } |
| 162 | |
| 163 | void |
| 164 | initialize_notif (void) |
| 165 | { |
| 166 | int i = 0; |
| 167 | |
| 168 | for (i = 0; i < ARRAY_SIZE (notifs); i++) |
| 169 | notifs[i]->queue |
| 170 | = QUEUE_alloc (notif_event_p, notif_event_xfree); |
| 171 | } |