[systemd-devel] [PATCH 3/5] fsckd: Reduce the SAK window when writing to console

[Lennart Poettering]

On Tue, 10.03.15 11:33, Didier Roche (didrocks at ubuntu.com) wrote:

Looks good, applied!

Thanks for looking into this!

> >From 3e877d1d493476f63fa6af7997914f93b50218bd Mon Sep 17 00:00:00 2001
> From: Didier Roche <didrocks at ubuntu.com>
> Date: Tue, 10 Mar 2015 09:57:38 +0100
> Subject: [PATCH 3/5] fsckd: Reduce the SAK window when writing to console
> 
> We don't want to keep /dev/console open all the time, but only open it when
> needed, to avoid interfering with SAK.
> ---
>  src/fsckd/fsckd.c | 66 ++++++++++++++++++++++++++++++++-----------------------
>  1 file changed, 39 insertions(+), 27 deletions(-)
> 
> diff --git a/src/fsckd/fsckd.c b/src/fsckd/fsckd.c
> index 9393379..f73d23b 100644
> --- a/src/fsckd/fsckd.c
> +++ b/src/fsckd/fsckd.c
> @@ -76,12 +76,12 @@ typedef struct Manager {
>          LIST_HEAD(Client, clients);
>          unsigned n_clients;
>  
> -        int clear;
> +        size_t clear;
>  
>          int connection_fd;
>          sd_event_source *connection_event_source;
>  
> -        FILE *console;
> +        bool show_status_console;
>  
>          double percent;
>          int numdevices;
> @@ -99,6 +99,36 @@ static void manager_free(Manager *m);
>  DEFINE_TRIVIAL_CLEANUP_FUNC(Client*, client_free);
>  DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
>  
> +static int manager_write_console(Manager *m, const char *message) {
> +        _cleanup_fclose_ FILE *console = NULL;
> +        int l;
> +        size_t j;
> +
> +        assert(m);
> +
> +        if (!m->show_status_console)
> +                return 0;
> +
> +        /* Reduce the SAK window by opening and closing console on every request */
> +        console = fopen("/dev/console", "we");
> +        if (!console)
> +                return -errno;
> +
> +        if (message) {
> +                fprintf(console, "\r%s\r%n", message, &l);
> +                if (m->clear  < (size_t)l)
> +                        m->clear = (size_t)l;
> +        } else {
> +                fputc('\r', console);
> +                for (j = 0; j < m->clear; j++)
> +                        fputc(' ', console);
> +                fputc('\r', console);
> +        }
> +        fflush(console);
> +
> +        return 0;
> +}
> +
>  static double compute_percent(int pass, size_t cur, size_t max) {
>          /* Values stolen from e2fsck */
>  
> @@ -284,7 +314,7 @@ static int manager_update_global_progress(Manager *m) {
>          Client *current = NULL;
>          _cleanup_free_ char *console_message = NULL;
>          _cleanup_free_ char *fsck_message = NULL;
> -        int current_numdevices = 0, l = 0, r;
> +        int current_numdevices = 0, r;
>          double current_percent = 100;
>  
>          /* get the overall percentage */
> @@ -311,19 +341,15 @@ static int manager_update_global_progress(Manager *m) {
>                  if (asprintf(&fsck_message, "fsckd:%d:%3.1f:%s", m->numdevices, m->percent, console_message) < 0)
>                          return -ENOMEM;
>  
> -                /* write to console */
> -                if (m->console) {
> -                        fprintf(m->console, "\r%s\r%n", console_message, &l);
> -                        fflush(m->console);
> -                }
> +                r = manager_write_console(m, console_message);
> +                if (r < 0)
> +                        return r;
>  
>                  /* try to connect to plymouth and send message */
>                  r = manager_send_plymouth_message(m, fsck_message);
>                  if (r < 0)
>                          log_debug("Couldn't send message to plymouth");
>  
> -                if (l > m->clear)
> -                        m->clear = l;
>          }
>          return 0;
>  }
> @@ -435,15 +461,7 @@ static void manager_free(Manager *m) {
>                  return;
>  
>          /* clear last line */
> -        if (m->console && m->clear > 0) {
> -                unsigned j;
> -
> -                fputc('\r', m->console);
> -                for (j = 0; j < (unsigned) m->clear; j++)
> -                        fputc(' ', m->console);
> -                fputc('\r', m->console);
> -                fflush(m->console);
> -        }
> +        manager_write_console(m, NULL);
>  
>          sd_event_source_unref(m->connection_event_source);
>          safe_close(m->connection_fd);
> @@ -453,9 +471,6 @@ static void manager_free(Manager *m) {
>  
>          manager_disconnect_plymouth(m);
>  
> -        if (m->console)
> -                fclose(m->console);
> -
>          sd_event_unref(m->event);
>  
>          free(m);
> @@ -479,11 +494,8 @@ static int manager_new(Manager **ret, int fd) {
>          if (r < 0)
>                  return r;
>  
> -        if (access("/run/systemd/show-status", F_OK) >= 0) {
> -                m->console = fopen("/dev/console", "we");
> -                if (!m->console)
> -                        return -errno;
> -        }
> +        if (access("/run/systemd/show-status", F_OK) >= 0)
> +                m->show_status_console = true;
>  
>          r = sd_event_add_io(m->event, &m->connection_event_source, fd, EPOLLIN, manager_new_connection_handler, m);
>          if (r < 0)
> -- 
> 2.1.4
> 

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Lennart

-- 
Lennart Poettering, Red Hat