log the container console when it is daemonized and the log is enabled

When we daemonize the container and we specify the log file,
the container will use the log file to write the console output.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index b5a34a7b5fee1a59006ba3c65bab4ed1f2cbca27..9c90771adeb1632e8565c030a2b52f245fc8cebf 100644 (file)
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -135,9 +135,30 @@ int main(int argc, char *argv[])
                         my_args.progname, my_args.quiet))
                return err;
 
-       if (my_args.daemonize && daemon(0 ,0)) {
-               SYSERROR("failed to daemonize '%s'", my_args.name);
-               return err;
+       if (my_args.daemonize) {
+
+                /* do not chdir as we want to open the log file,
+                * change the directory right after.
+                * do not close 0, 1, 2, we want to do that
+                * ourself because we don't want /dev/null
+                * being reopened.
+                */
+               if (daemon(1 ,1)) {
+                       SYSERROR("failed to daemonize '%s'", my_args.name);
+                       return err;
+               }
+
+               close(0);
+               close(1);
+               close(2);
+
+               if (my_args.log_file) {
+                       open(my_args.log_file, O_WRONLY | O_CLOEXEC);
+                       open(my_args.log_file, O_RDONLY | O_CLOEXEC);
+                       open(my_args.log_file, O_RDONLY | O_CLOEXEC);
+               }
+
+               chdir("/");
        }
 
        save_tty(&tios);

diff --git a/src/lxc/start.c b/src/lxc/start.c
index c3340bb22b0321abc336c77a0af70de562aa4647..0b085604ea0c1fa41fc43871f16f8d13de8165f6 100644 (file)
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -332,6 +332,41 @@ static void remove_init_pid(const char *name, pid_t pid)
        unlink(init);
 }
 
+static int fdname(int fd, char *name, size_t size)
+{
+       char path[MAXPATHLEN];
+
+       snprintf(path, MAXPATHLEN, "/proc/self/fd/%d", fd);
+
+       return readlink(path, name, size) < 0 ? -1 : 0;
+}
+
+static int console_init(char *console, size_t size)
+{
+       struct stat stat;
+       int i;
+
+       for (i = 0; i < 3; i++) {
+               if (!isatty(i))
+                       continue;
+
+               if (ttyname_r(i, console, size)) {
+                       SYSERROR("failed to retrieve tty name");
+                       return -1;
+               }
+               return 0;
+       }
+
+       if (!fstat(0, &stat)) {
+               if (S_ISREG(stat.st_mode) || S_ISCHR(stat.st_mode) ||
+                   S_ISFIFO(stat.st_mode) || S_ISLNK(stat.st_mode))
+                       return fdname(0, console, size);
+       }
+
+       console[0] = '\0';
+       return 0;
+}
+
 int lxc_init(const char *name, struct lxc_handler *handler)
 {
        int err = -1;
@@ -348,9 +383,10 @@ int lxc_init(const char *name, struct lxc_handler *handler)
                goto out_put_lock;
        }
 
-       /* If we are not attached to a tty, disable it */
-       if (ttyname_r(0, handler->tty, sizeof(handler->tty)))
-               handler->tty[0] = '\0';
+       if (console_init(handler->tty, sizeof(handler->tty))) {
+               ERROR("failed to initialize the console");
+               goto out_aborting;
+       }
 
        if (lxc_create_tty(name, &handler->tty_info)) {
                ERROR("failed to create the ttys");