Re: [PATCH BlueZ v3] monitor: Add option to set fallback width

[Sonny Sasaka <sonnysasaka@chromium.org>]

Hi Marcel, please take another look at v4 of this patch. Since you
mention of making it a global variable, I remove the variable passing
altogether and instead added an interface to set the global pager
width.

On Sat, Feb 27, 2021 at 12:22 PM Marcel Holtmann <marcel@holtmann.org> wrote:
>
> Hi Sonny,
>
> > Sometimes we want to be able to pipe the output of btmon to a
> > non-terminal device. The current fallback width is usually not long
> > enough so this patch adds an option to specify the column width. This is
> > especially needed for text logs from bluetoothd.
> >
> > Reviewed-by: Daniel Winkler <danielwinkler@google.com>
> >
> > ---
> > monitor/control.c |  4 ++--
> > monitor/control.h |  2 +-
> > monitor/display.c |  8 ++++++--
> > monitor/display.h |  2 +-
> > monitor/main.c    | 10 ++++++++--
> > 5 files changed, 18 insertions(+), 8 deletions(-)
> >
> > diff --git a/monitor/control.c b/monitor/control.c
> > index d1ba97d37..2fab87320 100644
> > --- a/monitor/control.c
> > +++ b/monitor/control.c
> > @@ -1474,7 +1474,7 @@ bool control_writer(const char *path)
> >       return !!btsnoop_file;
> > }
> >
> > -void control_reader(const char *path, bool pager)
> > +void control_reader(const char *path, bool pager, int num_columns)
> > {
> >       unsigned char buf[BTSNOOP_MAX_PACKET_SIZE];
> >       uint16_t pktlen;
> > @@ -1500,7 +1500,7 @@ void control_reader(const char *path, bool pager)
> >       }
> >
> >       if (pager)
> > -             open_pager();
> > +             open_pager(num_columns);
> >
> >       switch (format) {
> >       case BTSNOOP_FORMAT_HCI:
> > diff --git a/monitor/control.h b/monitor/control.h
> > index 29616c4f1..b96c542fc 100644
> > --- a/monitor/control.h
> > +++ b/monitor/control.h
> > @@ -12,7 +12,7 @@
> > #include <stdint.h>
> >
> > bool control_writer(const char *path);
> > -void control_reader(const char *path, bool pager);
> > +void control_reader(const char *path, bool pager, int num_columns);
> > void control_server(const char *path);
> > int control_tty(const char *path, unsigned int speed);
> > int control_rtt(char *jlink, char *rtt);
> > diff --git a/monitor/display.c b/monitor/display.c
> > index b11b71d5d..08db18147 100644
> > --- a/monitor/display.c
> > +++ b/monitor/display.c
> > @@ -28,6 +28,7 @@
> > #include "display.h"
> >
> > static pid_t pager_pid = 0;
> > +static int n_columns = FALLBACK_TERMINAL_WIDTH;
>
> hmmm. Wouldn’t be default_num_columns better a bit better here and more descriptive what the variable does?
>
> >
> > bool use_color(void)
> > {
> > @@ -48,7 +49,8 @@ int num_columns(void)
> >
> >               if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0 ||
> >                                                               ws.ws_col == 0)
> > -                     cached_num_columns = FALLBACK_TERMINAL_WIDTH;
> > +                     cached_num_columns = n_columns > 0 ?
> > +                             n_columns : FALLBACK_TERMINAL_WIDTH;
>
> Just set cached_num_columns = default_num_columns.
>
> >               else
> >                       cached_num_columns = ws.ws_col;
> >       }
> > @@ -81,12 +83,14 @@ static void wait_for_terminate(pid_t pid)
> >       }
> > }
> >
> > -void open_pager(void)
> > +void open_pager(int columns)
> > {
> >       const char *pager;
> >       pid_t parent_pid;
> >       int fd[2];
> >
> > +     n_columns = columns;
> > +
> >       if (pager_pid > 0)
> >               return;
> >
> > diff --git a/monitor/display.h b/monitor/display.h
> > index f3a614b81..97aac8f7a 100644
> > --- a/monitor/display.h
> > +++ b/monitor/display.h
> > @@ -75,5 +75,5 @@ static inline uint64_t print_bitfield(int indent, uint64_t val,
> >
> > int num_columns(void);
> >
> > -void open_pager(void);
> > +void open_pager(int);
>
> I know that this is fine, but don’t do that. Include the parameter name please.
>
> > void close_pager(void);
> > diff --git a/monitor/main.c b/monitor/main.c
> > index 0f5eb4a3b..23a16660f 100644
> > --- a/monitor/main.c
> > +++ b/monitor/main.c
> > @@ -67,6 +67,7 @@ static void usage(void)
> >               "\t                       Read data from RTT\n"
> >               "\t-R  --rtt [<address>],[<area>],[<name>]\n"
> >               "\t                       RTT control block parameters\n"
> > +             "\t-C, --column [width]   Output width if not a terminal\n"
> >               "\t-h, --help             Show help options\n");
> > }
> >
> > @@ -90,6 +91,7 @@ static const struct option main_options[] = {
> >       { "no-pager",  no_argument,       NULL, 'P' },
> >       { "jlink",     required_argument, NULL, 'J' },
> >       { "rtt",       required_argument, NULL, 'R' },
> > +     { "column",    required_argument, NULL, 'C' },
>
> Not plural “columns” here?
>
> >       { "todo",      no_argument,       NULL, '#' },
> >       { "version",   no_argument,       NULL, 'v' },
> >       { "help",      no_argument,       NULL, 'h' },
> > @@ -110,6 +112,7 @@ int main(int argc, char *argv[])
> >       const char *str;
> >       char *jlink = NULL;
> >       char *rtt = NULL;
> > +     int num_columns = 0;
> >       int exit_status;
> >
> >       mainloop_init();
> > @@ -121,7 +124,7 @@ int main(int argc, char *argv[])
> >               struct sockaddr_un addr;
> >
> >               opt = getopt_long(argc, argv,
> > -                                     "r:w:a:s:p:i:d:B:V:MNtTSAE:PJ:R:vh",
> > +                                     "r:w:a:s:p:i:d:B:V:MNtTSAE:PJ:R:C:vh",
> >                                       main_options, NULL);
> >               if (opt < 0)
> >                       break;
> > @@ -205,6 +208,9 @@ int main(int argc, char *argv[])
> >               case 'R':
> >                       rtt = optarg;
> >                       break;
> > +             case 'C':
> > +                     num_columns = atoi(optarg);
> > +                     break;
>
> I would have set here default_num_columns global variable.
>
> >               case '#':
> >                       packet_todo();
> >                       lmp_todo();
> > @@ -245,7 +251,7 @@ int main(int argc, char *argv[])
> >               if (ellisys_server)
> >                       ellisys_enable(ellisys_server, ellisys_port);
> >
> > -             control_reader(reader_path, use_pager);
> > +             control_reader(reader_path, use_pager, num_columns);
> >               return EXIT_SUCCESS;
> >       }
>
> Regards
>
> Marcel
>