fix the way relative paths are handled and pid file handler

* add a pid file option on command line + implement it
* make the relative path in conf param relative to the configuration
  file directory and not the running directory

inc/utils.h

@@ -1,6 +1,8 @@
 #include "rfc3161.h"
 
 void skeleton_daemon();
+int init_pid(char *pidfile_path);
+int write_pid(char *pidfile_path);
 void uts_logger(rfc3161_context *ct, int priority, char *fmt, ...);
 void log_hex(rfc3161_context *ct, int priority, char *id,
              unsigned char *content, int content_length);

src/cmd/uts-server.c

@@ -6,6 +6,7 @@
 #include <getopt.h>
 #include <argp.h>
 #include <sys/syslog.h>
+#include <libgen.h>
 #include "http.h"
 
 const char *argp_program_version = UTS_VERSION;
@@ -18,6 +19,7 @@ static char doc[] = "\nUTS micro timestamp server (RFC 3161)";
 static struct argp_option options[] = {
     {"conffile", 'c', "CONFFILE", 0, "Path to configuration file"},
     {"daemonize", 'd', 0, 0, "Launch as a daemon"},
+    {"pidfile", 'p', "PIDFILE", 0, "Path to pid file"},
     {"debug", 'D', 0, 0, "STDOUT debugging"},
     {0}};
 
@@ -29,6 +31,7 @@ struct arguments {
     int daemonize;
     bool stdout_dbg;
     char *conffile;
+    char *pidfile;
 };
 
 static error_t parse_opt(int key, char *arg, struct argp_state *state) {
@@ -46,6 +49,9 @@ static error_t parse_opt(int key, char *arg, struct argp_state *state) {
     case 'c':
         arguments->conffile = arg;
         break;
+    case 'p':
+        arguments->pidfile = arg;
+        break;
     default:
         return ARGP_ERR_UNKNOWN;
     }
@@ -58,27 +64,50 @@ static struct argp argp = {options, parse_opt, args_doc, doc};
 int main(int argc, char **argv) {
     struct arguments args;
     args.conffile = NULL;
+    args.pidfile = NULL;
     args.daemonize = 0;
     args.stdout_dbg = 0;
     argp_parse(&argp, argc, argv, 0, 0, &args);
     int ret = EXIT_SUCCESS;
 
-    // get the current path, the configuration can be relative to this path
-    char conf_wd[PATH_MAX];
-    if (getcwd(conf_wd, sizeof(conf_wd)) == NULL) {
-        syslog(LOG_CRIT, "unable to get the current, uts-server start failed");
+    // get the full path of the configuration (daemon -> chdir to / concequently
+    // full path is necessary)
+    char conf_fp[PATH_MAX];
+    if (realpath(args.conffile, conf_fp) == NULL) {
+        syslog(LOG_CRIT, "unable to get the full path of the configuration "
+                         "file, uts-server start failed");
         return EXIT_FAILURE;
     }
 
+    init_pid(args.pidfile);
+    // get the full path for the pid file
+    char pid_file[PATH_MAX];
+    if (realpath(args.pidfile, pid_file) == NULL) {
+        syslog(LOG_CRIT, "unable to get the full path of the pid "
+                         "file, uts-server start failed");
+        return EXIT_FAILURE;
+    }
+
+    // get the directory containing the configuration file
+    // other uts-server files (ca, certs, etc) can be declared relatively to the
+    // configuration file
+    char *conf_wd = strdup(conf_fp);
+    dirname(conf_wd);
+
     if (args.daemonize)
         skeleton_daemon();
 
     syslog(LOG_NOTICE,
            "uts-server daemon starting with conf '%s' from working dir '%s'",
-           args.conffile, conf_wd);
+           conf_fp, conf_wd);
+
+    if (write_pid(pid_file) == 0) {
+        syslog(LOG_CRIT, "failed to write pid file '%s'", pid_file);
+        return EXIT_FAILURE;
+    }
 
     while (1) {
-        ret = http_server_start(args.conffile, conf_wd, args.stdout_dbg);
+        ret = http_server_start(conf_fp, conf_wd, args.stdout_dbg);
         break;
     }
 

src/lib/utils.c

@@ -10,6 +10,8 @@
 #include <errno.h>
 #include <string.h>
 #include <syslog.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include "utils.h"
 
 typedef struct _code {
@@ -38,6 +40,47 @@ static void signal_handler_up(int sig_num) {
     g_uts_sig_up = sig_num;
 }
 
+int init_pid(char *pidfile_path) {
+    // if pidfile_path is null, the user did not request one
+    // exit success
+    if (pidfile_path == NULL)
+        return 1;
+
+    int fd = open(pidfile_path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+    // in case we can't open it
+    if (fd == -1) {
+        syslog(LOG_CRIT, "failed to open the pid file");
+        return 0;
+    }
+
+    close(fd);
+    return 1;
+}
+
+int write_pid(char *pidfile_path) {
+    // if pidfile_path is null, the user did not request one
+    // exit success
+    if (pidfile_path == NULL)
+        return 1;
+
+    int fd = open(pidfile_path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+    // in case we can't open it
+    if (fd == -1) {
+        syslog(LOG_CRIT, "failed to open the pid file");
+        return 0;
+    }
+
+    char buf[100];
+    snprintf(buf, 100, "%ld\n", (long)getpid());
+    if (write(fd, buf, strlen(buf)) != strlen(buf)) {
+        syslog(LOG_CRIT, "failed to write the pid");
+        close(fd);
+        return 0;
+    }
+    close(fd);
+    return 1;
+}
+
 void skeleton_daemon() {
     pid_t pid;