Hi, On 10/17/25 1:04 PM, Jonas Rebmann wrote: > Previously, `dmesg -c` would clear the logbuffer except for the last 10 > lines. This comes with a fair amount of surprise given linux `dmesg -c` > clears the whole logbuffer. > > Clear the complete logbuffer given `dmesg -c` but with an optional > argument `dmesg -c [<num>]` to keep <num> lines. > > While at it, move the deleteion of log lines to the log_print function
deletion > to prevent a corner case of lost log message if they arrive between the > log_print() and log_clean() in dmesg. > > If loglevels are selected using -l or -p in addition to cleaning being > selected using -c, only clean those messages shown by the loglevel > selection. Given that this might break test suites, I think it warrants a short addition to migration-2025.11.0.rst (create if needed). > > Signed-off-by: Jonas Rebmann <[email protected]> > --- > commands/dmesg.c | 17 ++++++++++------- > common/console_common.c | 20 +++++++++++++++++--- > include/linux/printk.h | 2 +- > 3 files changed, 28 insertions(+), 11 deletions(-) > > diff --git a/commands/dmesg.c b/commands/dmesg.c > index a93ad5b359..6853f3afc9 100644 > --- a/commands/dmesg.c > +++ b/commands/dmesg.c > @@ -77,14 +77,20 @@ static unsigned dmesg_get_levels(const char *__args) > static int do_dmesg(int argc, char *argv[]) > { > int opt, ret, i; > - int delete_buf = 0, emit = 0; > + int delete_buf = -1, emit = 0; just make it unsigned and use UINT_MAX? delete_buf is no longer a good name for the variable IMO. > unsigned flags = 0, levels = 0; > char *set = NULL; > > - while ((opt = getopt(argc, argv, "ctderl:p:n:")) > 0) { > + while ((opt = getopt(argc, argv, "c::tderl:p:n:")) > 0) { > switch (opt) { > case 'c': > - delete_buf = 1; > + if (optarg) { > + ret = kstrtoint(optarg, 10, &delete_buf); With type changed above, kstrtouint > + if (ret || delete_buf < 0) ... which simplifies this condition. > + return COMMAND_ERROR_USAGE; > + } else { > + delete_buf = 0; You can initialize this right after case '0': and drop the else. > + } > break; > case 't': > flags |= BAREBOX_LOG_PRINT_TIME; > @@ -155,13 +161,10 @@ static int do_dmesg(int argc, char *argv[]) > return 0; > } > > - ret = log_print(flags, levels); > + ret = log_print(flags, levels, delete_buf); Not sure, we want to overload log_print with this. How about we switch the ctrlc() to ctrlc_non_interruptible() and then we are certain that there will be no messages coming in between as there will be no resched() points (barebox multitasking is completely cooperative). > -int log_print(unsigned flags, unsigned levels) > +/** Thanks for adding docs :) > + if (delete_buf >= 0 && barebox_logbuf_num_messages > delete_buf) If delete_buf were unsigned, it would simplify the condition. The variable name is suboptimal though, something with keep in it would be better. Cheers, Ahmad -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
