blob: ba07ebe01ccc75a723edab575492c8fe149586ca [file] [log] [blame]
/*
* Wrapper to make haproxy systemd-compliant.
*
* Copyright 2013 Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
*
* 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.
*
*/
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#define REEXEC_FLAG "HAPROXY_SYSTEMD_REEXEC"
#define SD_DEBUG "<7>"
#define SD_NOTICE "<5>"
static char *pid_file = "/run/haproxy.pid";
static int wrapper_argc;
static char **wrapper_argv;
static void locate_haproxy(char *buffer, size_t buffer_size)
{
char *end = NULL;
if (readlink("/proc/self/exe", buffer, buffer_size) > 0)
end = strrchr(buffer, '/');
if (end == NULL) {
strncpy(buffer, "/usr/sbin/haproxy", buffer_size);
return;
}
end[1] = '\0';
strncpy(end + 1, "haproxy", buffer + buffer_size - (end + 1));
buffer[buffer_size - 1] = '\0';
}
static void spawn_haproxy(char **pid_strv, int nb_pid)
{
char haproxy_bin[512];
pid_t pid;
int main_argc;
char **main_argv;
main_argc = wrapper_argc - 1;
main_argv = wrapper_argv + 1;
pid = fork();
if (!pid) {
/* 3 for "haproxy -Ds -sf" */
char **argv = calloc(4 + main_argc + nb_pid + 1, sizeof(char *));
int i;
int argno = 0;
locate_haproxy(haproxy_bin, 512);
argv[argno++] = haproxy_bin;
for (i = 0; i < main_argc; ++i)
argv[argno++] = main_argv[i];
argv[argno++] = "-Ds";
if (nb_pid > 0) {
argv[argno++] = "-sf";
for (i = 0; i < nb_pid; ++i)
argv[argno++] = pid_strv[i];
}
argv[argno] = NULL;
fprintf(stderr, SD_DEBUG "haproxy-systemd-wrapper: executing ");
for (i = 0; argv[i]; ++i)
fprintf(stderr, "%s ", argv[i]);
fprintf(stderr, "\n");
execv(argv[0], argv);
exit(0);
}
}
static int read_pids(char ***pid_strv)
{
FILE *f = fopen(pid_file, "r");
int read = 0, allocated = 8;
char pid_str[10];
if (!f)
return 0;
*pid_strv = malloc(allocated * sizeof(char *));
while (1 == fscanf(f, "%s\n", pid_str)) {
if (read == allocated) {
allocated *= 2;
*pid_strv = realloc(*pid_strv, allocated * sizeof(char *));
}
(*pid_strv)[read++] = strdup(pid_str);
}
fclose(f);
return read;
}
static void sigusr2_handler(int signum __attribute__((unused)))
{
setenv(REEXEC_FLAG, "1", 1);
fprintf(stderr, SD_NOTICE "haproxy-systemd-wrapper: re-executing\n");
execv(wrapper_argv[0], wrapper_argv);
}
static void sigint_handler(int signum __attribute__((unused)))
{
int i, pid;
char **pid_strv = NULL;
int nb_pid = read_pids(&pid_strv);
for (i = 0; i < nb_pid; ++i) {
pid = atoi(pid_strv[i]);
if (pid > 0) {
fprintf(stderr, SD_DEBUG "haproxy-systemd-wrapper: SIGINT -> %d\n", pid);
kill(pid, SIGINT);
free(pid_strv[i]);
}
}
free(pid_strv);
}
static void init(int argc, char **argv)
{
while (argc > 1) {
if (**argv == '-') {
char *flag = *argv + 1;
--argc; ++argv;
if (*flag == 'p')
pid_file = *argv;
}
--argc; ++argv;
}
}
int main(int argc, char **argv)
{
int status;
wrapper_argc = argc;
wrapper_argv = argv;
--argc; ++argv;
init(argc, argv);
signal(SIGINT, &sigint_handler);
signal(SIGUSR2, &sigusr2_handler);
if (getenv(REEXEC_FLAG) != NULL) {
/* We are being re-executed: restart HAProxy gracefully */
int i;
char **pid_strv = NULL;
int nb_pid = read_pids(&pid_strv);
sigset_t sigs;
unsetenv(REEXEC_FLAG);
spawn_haproxy(pid_strv, nb_pid);
/* Unblock SIGUSR2 which was blocked by the signal handler
* before re-exec */
sigprocmask(SIG_BLOCK, NULL, &sigs);
sigdelset(&sigs, SIGUSR2);
sigprocmask(SIG_SETMASK, &sigs, NULL);
for (i = 0; i < nb_pid; ++i)
free(pid_strv[i]);
free(pid_strv);
}
else {
/* Start a fresh copy of HAProxy */
spawn_haproxy(NULL, 0);
}
status = -1;
while (-1 != wait(&status) || errno == EINTR)
;
fprintf(stderr, SD_NOTICE "haproxy-systemd-wrapper: exit, haproxy RC=%d\n",
status);
return status;
}