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Message-id: <1456314801-32738-3-git-send-email-k.krosman@samsung.com>
Date: Wed, 24 Feb 2016 12:53:15 +0100
From: Kazimierz Krosman <k.krosman@...sung.com>
To: akpm@...ux-foundation.org, peter@...leysoftware.com, tj@...nel.org,
vvs@...tuozzo.com, corbet@....net, arnd@...db.de, pmladek@...e.cz,
gregkh@...uxfoundation.org, daniel@...que.org,
kay.sievers@...y.org, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-api@...r.kernel.org
Cc: k.lewandowsk@...sung.com, k.krosman@...sung.com,
m.niesluchow@...sung.com, richard.weinberger@...il.com,
b.zolnierkie@...sung.com, luto@...capital.net,
knhoon.baik@...sung.com
Subject: [PATCH v6 2/8] printk: add one function for storing log in proper
format
From: Marcin Niesluchowski <m.niesluchow@...sung.com>
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 <m.niesluchow@...sung.com>
Signed-off-by: Paul Osmialowski <p.osmialowsk@...sung.com>
[Rebased kmsg patch v5 on Linux 4.5-rc5]
Signed-off-by: Kazimierz Krosman <k.krosman@...sung.com>
---
kernel/printk/printk.c | 222 ++++++++++++++++++++++++++-----------------------
1 file changed, 119 insertions(+), 103 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 2787bc7..3653a8e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -179,6 +179,27 @@ static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;
+/*
+ * Continuation lines are buffered, and not committed to the record buffer
+ * until the line is complete, or a race forces it. The line fragments
+ * though, are printed immediately to the consoles to ensure everything has
+ * reached the console in case of a kernel crash.
+ */
+static struct cont {
+ char buf[LOG_LINE_MAX];
+ size_t len; /* length == 0 means unused buffer */
+ size_t cons; /* bytes written to console */
+ struct task_struct *owner; /* task of first print*/
+ u64 ts_nsec; /* time of first print */
+ u8 level; /* log level of first message */
+ u8 facility; /* log facility of first message */
+ enum log_flags flags; /* prefix, newline flags */
+ bool flushed:1; /* buffer sealed and committed */
+} cont;
+
+static void cont_flush(enum log_flags flags);
+static bool cont_add(int facility, int level, const char *text, size_t len);
+
/* Return log buffer address */
char *log_buf_addr_get(void)
{
@@ -330,6 +351,102 @@ static int log_store(int facility, int level,
return msg->text_len;
}
+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)
@@ -1164,24 +1281,6 @@ static inline void printk_delay(void)
}
}
-/*
- * Continuation lines are buffered, and not committed to the record buffer
- * until the line is complete, or a race forces it. The line fragments
- * though, are printed immediately to the consoles to ensure everything has
- * reached the console in case of a kernel crash.
- */
-static struct cont {
- char buf[LOG_LINE_MAX];
- size_t len; /* length == 0 means unused buffer */
- size_t cons; /* bytes written to console */
- struct task_struct *owner; /* task of first print*/
- u64 ts_nsec; /* time of first print */
- u8 level; /* log level of first message */
- u8 facility; /* log facility of first message */
- enum log_flags flags; /* prefix, newline flags */
- bool flushed:1; /* buffer sealed and committed */
-} cont;
-
static void cont_flush(enum log_flags flags)
{
if (cont.flushed)
@@ -1277,10 +1376,6 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *fmt, va_list args)
{
static bool recursion_bug;
- static char textbuf[LOG_LINE_MAX];
- char *text = textbuf;
- size_t text_len = 0;
- enum log_flags lflags = 0;
unsigned long flags;
int this_cpu;
int printed_len = 0;
@@ -1334,87 +1429,8 @@ asmlinkage int vprintk_emit(int facility, int level,
strlen(recursion_msg));
}
- /*
- * 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);
- }
+ printed_len += log_format_and_store(facility, level, dict, dictlen,
+ fmt, args);
logbuf_cpu = UINT_MAX;
raw_spin_unlock(&logbuf_lock);
--
1.9.1
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