[RFC v2 2/9] printk: add one function for storing log in proper format

[Paul Osmialowski]

From: Marcin Niesluchowski 

Preparation commit for future changes purpose.

Separate code responsible for storing log message in proper format
from operations on consoles by putting it in another function.

Signed-off-by: Marcin Niesluchowski 
---
 kernel/printk/printk.c | 183 ++---
 1 file changed, 98 insertions(+), 85 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d209072..e7b2a78 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -602,6 +602,102 @@ static size_t cont_print_text(char *text, size_t size)
return textlen;
 }
 
+static int log_format_and_store(int facility, int level,
+   const char *dict, size_t dictlen,
+   const char *fmt, va_list args)
+{
+   static char textbuf[LOG_LINE_MAX];
+   char *text = textbuf;
+   size_t text_len = 0;
+   enum log_flags lflags = 0;
+   int printed_len = 0;
+
+   /*
+* The printf needs to come first; we need the syslog
+* prefix which might be passed-in as a parameter.
+*/
+   text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+
+   /* mark and strip a trailing newline */
+   if (text_len && text[text_len-1] == '\n') {
+   text_len--;
+   lflags |= LOG_NEWLINE;
+   }
+
+   /* strip kernel syslog prefix and extract log level or control flags */
+   if (facility == 0) {
+   int kern_level = printk_get_level(text);
+
+   if (kern_level) {
+   const char *end_of_header = printk_skip_level(text);
+
+   switch (kern_level) {
+   case '0' ... '7':
+   if (level == LOGLEVEL_DEFAULT)
+   level = kern_level - '0';
+   /* fallthrough */
+   case 'd':   /* KERN_DEFAULT */
+   lflags |= LOG_PREFIX;
+   }
+   /*
+* No need to check length here because vscnprintf
+* put '\0' at the end of the string. Only valid and
+* newly printed level is detected.
+*/
+   text_len -= end_of_header - text;
+   text = (char *)end_of_header;
+   }
+   }
+
+   if (level == LOGLEVEL_DEFAULT)
+   level = default_message_loglevel;
+
+   if (dict)
+   lflags |= LOG_PREFIX|LOG_NEWLINE;
+
+   if (!(lflags & LOG_NEWLINE)) {
+   /*
+* Flush the conflicting buffer. An earlier newline was missing,
+* or another task also prints continuation lines.
+*/
+   if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
+   cont_flush(LOG_NEWLINE);
+
+   /* buffer line if possible, otherwise store it right away */
+   if (cont_add(facility, level, text, text_len))
+   printed_len += text_len;
+   else
+   printed_len += log_store(facility, level,
+lflags | LOG_CONT, 0,
+dict, dictlen, text, text_len);
+   } else {
+   bool stored = false;
+
+   /*
+* If an earlier newline was missing and it was the same task,
+* either merge it with the current buffer and flush, or if
+* there was a race with interrupts (prefix == true) then just
+* flush it out and store this line separately.
+* If the preceding printk was from a different task and missed
+* a newline, flush and append the newline.
+*/
+   if (cont.len) {
+   if (cont.owner == current && !(lflags & LOG_PREFIX))
+   stored = cont_add(facility, level, text,
+ text_len);
+   cont_flush(LOG_NEWLINE);
+   }
+
+   if (stored)
+   printed_len += text_len;
+   else
+   printed_len += log_store(facility, level,
+lflags, 0, dict, dictlen,
+text, text_len);
+   }
+   return printed_len;
+}
+
 int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
 
 static int syslog_action_restricted(int type)
@@ -1657,10 +1753,6 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *fmt, va_list args)
 {
static int recursion_bug;
-   static char textbuf[LOG_LINE_MAX];
-   char *text = textbuf;
-   size_t 

[RFC v2 2/9] printk: add one function for storing log in proper format

[Paul Osmialowski]

From: Marcin Niesluchowski 

Preparation commit for future changes purpose.

Separate code responsible for storing log message in proper format
from operations on consoles by putting it in another function.

Signed-off-by: Marcin Niesluchowski 
---
 kernel/printk/printk.c | 183 ++---
 1 file changed, 98 insertions(+), 85 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d209072..e7b2a78 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -602,6 +602,102 @@ static size_t cont_print_text(char *text, size_t size)
return textlen;
 }
 
+static int log_format_and_store(int facility, int level,
+   const char *dict, size_t dictlen,
+   const char *fmt, va_list args)
+{
+   static char textbuf[LOG_LINE_MAX];
+   char *text = textbuf;
+   size_t text_len = 0;
+   enum log_flags lflags = 0;
+   int printed_len = 0;
+
+   /*
+* The printf needs to come first; we need the syslog
+* prefix which might be passed-in as a parameter.
+*/
+   text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+
+   /* mark and strip a trailing newline */
+   if (text_len && text[text_len-1] == '\n') {
+   text_len--;
+   lflags |= LOG_NEWLINE;
+   }
+
+   /* strip kernel syslog prefix and extract log level or control flags */
+   if (facility == 0) {
+   int kern_level = printk_get_level(text);
+
+   if (kern_level) {
+   const char *end_of_header = printk_skip_level(text);
+
+   switch (kern_level) {
+   case '0' ... '7':
+   if (level == LOGLEVEL_DEFAULT)
+   level = kern_level - '0';
+   /* fallthrough */
+   case 'd':   /* KERN_DEFAULT */
+   lflags |= LOG_PREFIX;
+   }
+   /*
+* No need to check length here because vscnprintf
+* put '\0' at the end of the string. Only valid and
+* newly printed level is detected.
+*/
+   text_len -= end_of_header - text;
+   text = (char *)end_of_header;
+   }
+   }
+
+   if (level == LOGLEVEL_DEFAULT)
+   level = default_message_loglevel;
+
+   if (dict)
+   lflags |= LOG_PREFIX|LOG_NEWLINE;
+
+   if (!(lflags & LOG_NEWLINE)) {
+   /*
+* Flush the conflicting buffer. An earlier newline was missing,
+* or another task also prints continuation lines.
+*/
+   if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
+   cont_flush(LOG_NEWLINE);
+
+   /* buffer line if possible, otherwise store it right away */
+   if (cont_add(facility, level, text, text_len))
+   printed_len += text_len;
+   else
+   printed_len += log_store(facility, level,
+lflags | LOG_CONT, 0,
+dict, dictlen, text, text_len);
+   } else {
+   bool stored = false;
+
+   /*
+* If an earlier newline was missing and it was the same task,
+* either merge it with the current buffer and flush, or if
+* there was a race with interrupts (prefix == true) then just
+* flush it out and store this line separately.
+* If the preceding printk was from a different task and missed
+* a newline, flush and append the newline.
+*/
+   if (cont.len) {
+   if (cont.owner == current && !(lflags & LOG_PREFIX))
+   stored = cont_add(facility, level, text,
+ text_len);
+   cont_flush(LOG_NEWLINE);
+   }
+
+   if (stored)
+   printed_len += text_len;
+   else
+   printed_len += log_store(facility, level,
+lflags, 0, dict, dictlen,
+text, text_len);
+   }
+   return printed_len;
+}
+
 int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
 
 static int syslog_action_restricted(int type)
@@ -1657,10 +1753,6 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *fmt, va_list args)
 {
static int recursion_bug;
-   static char