From 470bc6191952eb590b8157c4928190ef66fdd6ba Mon Sep 17 00:00:00 2001 From: Quentin Young Date: Tue, 20 Mar 2018 15:07:36 -0400 Subject: [PATCH] watchfrr, vtysh: do not write config during crash If a daemon is restarting, crashed, or otherwise in the process of reconnecting to watchfrr and a user issues "write memory" or "write file" the resulting config will not include the configuration of that daemon. This is problematic because this output will overwrite the previous config, potentially causing unintentional loss of configuration stored only in the config file based upon timing. This patch remedies that by making watchfrr check that all daemons are up before attempting a configuration write, and updating vtysh so that its failsafe respects this condition as well. Note that this issue only manifests when using integrated config. Signed-off-by: Quentin Young --- vtysh/vtysh.c | 7 ++++++- watchfrr/watchfrr.c | 10 ++++++++++ watchfrr/watchfrr.h | 7 +++++++ watchfrr/watchfrr_vty.c | 15 ++++++++++++++- 4 files changed, 37 insertions(+), 2 deletions(-) diff --git a/vtysh/vtysh.c b/vtysh/vtysh.c index efef106d97..1308e1218b 100644 --- a/vtysh/vtysh.c +++ b/vtysh/vtysh.c @@ -2477,7 +2477,12 @@ DEFUN (vtysh_write_memory, "do write integrated", outputfile); - if (ret != CMD_SUCCESS) { + /* + * If watchfrr returns CMD_WARNING_CONFIG_FAILED this means + * that it could not write the config, but additionally + * indicates that we should not try either + */ + if (ret != CMD_SUCCESS && ret != CMD_WARNING_CONFIG_FAILED) { printf("\nWarning: attempting direct configuration write without " "watchfrr.\nFile permissions and ownership may be " "incorrect, or write may fail.\n\n"); diff --git a/watchfrr/watchfrr.c b/watchfrr/watchfrr.c index dc3dcbf1e9..264882e21f 100644 --- a/watchfrr/watchfrr.c +++ b/watchfrr/watchfrr.c @@ -899,6 +899,16 @@ static int wakeup_send_echo(struct thread *t_wakeup) return 0; } +bool check_all_up(void) +{ + struct daemon *dmn; + + for (dmn = gs.daemons; dmn; dmn = dmn->next) + if (dmn->state != DAEMON_UP) + return false; + return true; +} + static void sigint(void) { zlog_notice("Terminating on signal"); diff --git a/watchfrr/watchfrr.h b/watchfrr/watchfrr.h index 53b92bd833..1a1c19056f 100644 --- a/watchfrr/watchfrr.h +++ b/watchfrr/watchfrr.h @@ -25,5 +25,12 @@ extern void watchfrr_vty_init(void); extern pid_t integrated_write_pid; extern void integrated_write_sigchld(int status); +/* + * Check if all daemons we are monitoring are in the DAEMON_UP state. + * + * Returns: + * True if they are all DAEMON_UP, false otherwise. + */ +extern bool check_all_up(void); #endif /* FRR_WATCHFRR_H */ diff --git a/watchfrr/watchfrr_vty.c b/watchfrr/watchfrr_vty.c index 1f872c91ff..1bfc41f255 100644 --- a/watchfrr/watchfrr_vty.c +++ b/watchfrr/watchfrr_vty.c @@ -40,11 +40,24 @@ DEFUN(config_write_integrated, pid_t child; sigset_t oldmask, sigmask; + const char *e_inprog = "Configuration write already in progress."; + const char *e_dmn = "Not all daemons are up, cannot write config."; + if (integrated_write_pid != -1) { - vty_out(vty, "%% configuration write already in progress.\n"); + vty_out(vty, "%% %s\n", e_inprog); return CMD_WARNING; } + /* check that all daemons are up before clobbering config */ + if (!check_all_up()) { + vty_out(vty, "%% %s\n", e_dmn); + /* + * vtysh interprets this return value to mean that it should + * not try to write the config itself + */ + return CMD_WARNING_CONFIG_FAILED; + } + fflush(stdout); fflush(stderr); -- 2.39.5