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/*
watchfrr CLI functions.
Copyright (C) 2016 David Lamparter for NetDEF, 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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <zebra.h>
#include <sys/wait.h>
#include "memory.h"
#include "log.h"
#include "vty.h"
#include "command.h"
#include "watchfrr.h"
pid_t integrated_write_pid;
static int integrated_result_fd;
DEFUN(config_write_integrated,
config_write_integrated_cmd,
"write integrated",
"Write running configuration to memory, network, or terminal\n"
"Write integrated all-daemon frr.conf file\n")
{
pid_t child;
sigset_t oldmask, sigmask;
if (integrated_write_pid != -1) {
vty_out(vty, "%% configuration write already in progress.%s",
VTY_NEWLINE);
return CMD_WARNING;
}
fflush(stdout);
fflush(stderr);
/* need to temporarily block SIGCHLD because it could arrive between
* fork() call and setting the integrated_write_pid variable. This
* would mean the completion call gets lost and this hangs forever.
*/
sigemptyset(&oldmask);
sigemptyset(&sigmask);
sigaddset(&sigmask, SIGCHLD);
sigprocmask(SIG_BLOCK, &sigmask, &oldmask);
child = fork();
if (child == -1) {
vty_out(vty, "%% configuration write fork() failed: %s.%s",
safe_strerror(errno), VTY_NEWLINE);
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return CMD_WARNING;
}
if (child != 0) {
/* note: the VTY won't write a command return value to vtysh; the
* session temporarily enters an intentional "hang" state. This is
* to make sure latency in vtysh doing the config write (several
* seconds is not rare to see) does not interfere with watchfrr's
* supervisor job.
*
* The fd is duplicated here so we don't need to hold a vty pointer
* (which could become invalid in the meantime).
*/
integrated_write_pid = child;
integrated_result_fd = dup(vty->wfd);
sigprocmask(SIG_SETMASK, &oldmask, NULL);
return CMD_SUSPEND;
}
/* redirect stdout/stderr to vty session. Note vty->wfd is marked
* CLOEXEC, but dup2 will clear that flag. */
dup2(vty->wfd, 1);
dup2(vty->wfd, 2);
/* don't allow the user to pass parameters, we're root here!
* should probably harden vtysh at some point too... */
execl(VTYSH_BIN_PATH, "vtysh", "-w", NULL);
/* unbuffered write; we just messed with stdout... */
char msg[512];
snprintf(msg, sizeof(msg), "error executing %s: %s\n",
VTYSH_BIN_PATH, safe_strerror(errno));
write(1, msg, strlen(msg));
exit(1);
}
void integrated_write_sigchld(int status)
{
uint8_t reply[4] = { 0, 0, 0, CMD_WARNING };
if (WIFEXITED(status)) {
zlog_info("configuration write completed with exit code %d",
WEXITSTATUS(status));
reply[3] = WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
zlog_warn("configuration write terminated by signal %d",
WTERMSIG(status));
} else {
zlog_warn("configuration write terminated");
}
if (reply[3] != CMD_SUCCESS) {
/* failure might be silent in vtysh without this */
static const char msg[] = "% Configuration write failed.\n";
write(integrated_result_fd, msg, strlen(msg));
}
/* don't care about failures here, if the connection is broken the
* return value will just be lost. */
write(integrated_result_fd, reply, sizeof(reply));
close(integrated_result_fd);
integrated_write_pid = -1;
}
void watchfrr_vty_init(void)
{
integrated_write_pid = -1;
install_element(ENABLE_NODE, &config_write_integrated_cmd);
}
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