Messages in this thread | | | Date | Tue, 19 Dec 2017 10:17:27 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCHv2] printk: add console_msg_format command line option |
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On Tue, 19 Dec 2017 17:42:43 +0900 Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 8a61d1eda677..543de386e01e 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -642,6 +642,20 @@ > console=brl,ttyS0 > For now, only VisioBraille is supported. > > + console_msg_format= > + [KNL] Change console messages format > + default > + By default we print messages on consoles in > + "[time stamp] text\n" format (time stamp may not be > + printed, depending on CONFIG_PRINTK_TIME or > + `printk_time' param). > + syslog > + Switch to syslog format: "<%u>[time stamp] text\n" > + IOW, each message will have a facility and loglevel > + prefix. The format is similar to one used by syslog() > + syscall, or to executing "dmesg -S --raw" or to reading > + from /proc/kmsg.
Just to clarify. This affects all consoles, not just serial?
> + > consoleblank= [KNL] The console blank (screen saver) timeout in > seconds. A value of 0 disables the blank timer. > Defaults to 0. > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index c2e713f6ae2e..16dd91260273 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -277,6 +277,13 @@ EXPORT_SYMBOL(console_set_on_cmdline); > /* Flag: console code may call schedule() */ > static int console_may_schedule; > > +enum con_msg_format { > + MSG_FORMAT_DEFAULT = 0, > + MSG_FORMAT_SYSLOG = (1 << 0), > +};
So the con_msg_format will be a flag (as denoted with the (1<<0)). Should we call it "con_msg_format_flags" to make it more obvious that these are treated as flags and not a simple number.
> + > +static int console_msg_format = MSG_FORMAT_DEFAULT; > + > /* > * The printk log buffer consists of a chain of concatenated variable > * length records. Every record starts with a record header, containing > @@ -1913,6 +1920,17 @@ static int __add_preferred_console(char *name, int idx, char *options, > c->index = idx; > return 0; > } > + > +static int __init console_msg_format_setup(char *str) > +{ > + if (!strncmp(str, "syslog", 6)) > + console_msg_format = MSG_FORMAT_SYSLOG; > + if (!strncmp(str, "default", 7))
You can use strcmp() instead of strncmp(), the init code will nul terminate the string for you before calling this function. Otherwise if we add "syslog_special" or "default_extra" they will be confused with the above.
-- Steve
> + console_msg_format = MSG_FORMAT_DEFAULT; > + return 1; > +} > +__setup("console_msg_format=", console_msg_format_setup); > + > /* > * Set up a console. Called via do_early_param() in init/main.c > * for each "console=" parameter in the boot command line. > @@ -2215,7 +2233,10 @@ void console_unlock(void) > goto skip; > } > > - len += msg_print_text(msg, false, text + len, sizeof(text) - len); > + len += msg_print_text(msg, > + console_msg_format & MSG_FORMAT_SYSLOG, > + text + len, > + sizeof(text) - len); > if (nr_ext_console_drivers) { > ext_len = msg_print_ext_header(ext_text, > sizeof(ext_text),
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