From 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:07:49 -0700 Subject: pstore/ram: Should update old dmesg buffer before reading Without the update, we'll only see the new dmesg buffer after the reboot, but previously we could see it right away. Making an oops visible in pstore filesystem before reboot is a somewhat dubious feature, but removing it wasn't an intentional change, so let's restore it. For this we have to make persistent_ram_save_old() safe for calling multiple times, and also extern it. Signed-off-by: Anton Vorontsov Acked-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram.c | 2 ++ fs/pstore/ram_core.c | 15 ++++++++------- 2 files changed, 10 insertions(+), 7 deletions(-) (limited to 'fs/pstore') diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 9123cce28c1e..16ff7332eae0 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -106,6 +106,8 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, time->tv_sec = 0; time->tv_nsec = 0; + /* Update old/shadowed buffer. */ + persistent_ram_save_old(prz); size = persistent_ram_old_size(prz); *buf = kmalloc(size, GFP_KERNEL); if (*buf == NULL) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 31f8d184f3a0..235513c46aaf 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -250,23 +250,24 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz, persistent_ram_update_ecc(prz, start, count); } -static void __init -persistent_ram_save_old(struct persistent_ram_zone *prz) +void persistent_ram_save_old(struct persistent_ram_zone *prz) { struct persistent_ram_buffer *buffer = prz->buffer; size_t size = buffer_size(prz); size_t start = buffer_start(prz); - char *dest; - persistent_ram_ecc_old(prz); + if (!size) + return; - dest = kmalloc(size, GFP_KERNEL); - if (dest == NULL) { + if (!prz->old_log) { + persistent_ram_ecc_old(prz); + prz->old_log = kmalloc(size, GFP_KERNEL); + } + if (!prz->old_log) { pr_err("persistent_ram: failed to allocate buffer\n"); return; } - prz->old_log = dest; prz->old_log_size = size; memcpy(prz->old_log, &buffer->data[start], size - start); memcpy(prz->old_log + size - start, &buffer->data[0], start); -- cgit v1.2.3 From 25b63da64708212985c06c7f8b089d356efdd9cf Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:07:50 -0700 Subject: pstore/ram_core: Do not reset restored zone's position and size Otherwise, the files will survive just one reboot, and on a subsequent boot they will disappear. Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram_core.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/pstore') diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 235513c46aaf..f6650d12c0c1 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -406,6 +406,7 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool " size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); persistent_ram_save_old(prz); + return 0; } } else { pr_info("persistent_ram: no valid data in buffer" -- cgit v1.2.3 From fce397930475f7efc712a1345dc0dad269a10544 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:07:51 -0700 Subject: pstore/ram_core: Factor persistent_ram_zap() out of post_init() A handy function that we will use outside of ram_core soon. But so far just factor it out and start using it in post_init(). Signed-off-by: Anton Vorontsov Acked-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram_core.c | 11 ++++++++--- include/linux/pstore_ram.h | 1 + 2 files changed, 9 insertions(+), 3 deletions(-) (limited to 'fs/pstore') diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index f6650d12c0c1..c5fbdbbf81ac 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -320,6 +320,13 @@ void persistent_ram_free_old(struct persistent_ram_zone *prz) prz->old_log_size = 0; } +void persistent_ram_zap(struct persistent_ram_zone *prz) +{ + atomic_set(&prz->buffer->start, 0); + atomic_set(&prz->buffer->size, 0); + persistent_ram_update_header_ecc(prz); +} + static void *persistent_ram_vmap(phys_addr_t start, size_t size) { struct page **pages; @@ -414,8 +421,7 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool } prz->buffer->sig = PERSISTENT_RAM_SIG; - atomic_set(&prz->buffer->start, 0); - atomic_set(&prz->buffer->size, 0); + persistent_ram_zap(prz); return 0; } @@ -450,7 +456,6 @@ struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start, goto err; persistent_ram_post_init(prz, ecc); - persistent_ram_update_header_ecc(prz); return prz; err: diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h index 4491e8ff36e6..3b823d49a85a 100644 --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -69,6 +69,7 @@ struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start, size_t size, bool ecc); void persistent_ram_free(struct persistent_ram_zone *prz); +void persistent_ram_zap(struct persistent_ram_zone *prz); struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev, bool ecc); -- cgit v1.2.3 From 93cce049682a1aebd49766f29af363e5b8770aed Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:07:52 -0700 Subject: pstore/ram: Should zap persistent zone on unlink Otherwise, unlinked file will reappear on the next boot. Reported-by: Kees Cook Signed-off-by: Anton Vorontsov Acked-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/pstore') diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 16ff7332eae0..453030f9c5bc 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -186,6 +186,7 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, return -EINVAL; persistent_ram_free_old(cxt->przs[id]); + persistent_ram_zap(cxt->przs[id]); return 0; } -- cgit v1.2.3 From 364ed2f4653d7c86ebedcc116a9cb34fd272867c Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Sat, 26 May 2012 06:07:53 -0700 Subject: pstore/inode: Make pstore_fill_super() static There's no reason to extern it. The patch fixes the annoying sparse warning: CHECK fs/pstore/inode.c fs/pstore/inode.c:264:5: warning: symbol 'pstore_fill_super' was not declared. Should it be static? Signed-off-by: Anton Vorontsov Acked-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/pstore') diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index aeb19e68e086..11a2aa2a56c4 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -258,7 +258,7 @@ fail: return rc; } -int pstore_fill_super(struct super_block *sb, void *data, int silent) +static int pstore_fill_super(struct super_block *sb, void *data, int silent) { struct inode *inode; -- cgit v1.2.3 From e2ae715d66bf4becfb85eb84b7150e23cf27df30 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 15 Jun 2012 14:07:51 +0200 Subject: kmsg - kmsg_dump() use iterator to receive log buffer content Provide an iterator to receive the log buffer content, and convert all kmsg_dump() users to it. The structured data in the kmsg buffer now contains binary data, which should no longer be copied verbatim to the kmsg_dump() users. The iterator should provide reliable access to the buffer data, and also supports proper log line-aware chunking of data while iterating. Signed-off-by: Kay Sievers Tested-by: Tony Luck Reported-by: Anton Vorontsov Tested-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/pseries/nvram.c | 61 +------- arch/x86/platform/mrst/early_printk_mrst.c | 13 +- drivers/mtd/mtdoops.c | 22 +-- fs/pstore/platform.c | 34 ++--- include/linux/kmsg_dump.h | 45 +++++- kernel/printk.c | 220 +++++++++++++++++++++++++---- 6 files changed, 258 insertions(+), 137 deletions(-) (limited to 'fs/pstore') diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c index 36f957f31842..8733a86ad52e 100644 --- a/arch/powerpc/platforms/pseries/nvram.c +++ b/arch/powerpc/platforms/pseries/nvram.c @@ -68,9 +68,7 @@ static const char *pseries_nvram_os_partitions[] = { }; static void oops_to_nvram(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, - const char *old_msgs, unsigned long old_len, - const char *new_msgs, unsigned long new_len); + enum kmsg_dump_reason reason); static struct kmsg_dumper nvram_kmsg_dumper = { .dump = oops_to_nvram @@ -503,28 +501,6 @@ int __init pSeries_nvram_init(void) return 0; } -/* - * Try to capture the last capture_len bytes of the printk buffer. Return - * the amount actually captured. - */ -static size_t capture_last_msgs(const char *old_msgs, size_t old_len, - const char *new_msgs, size_t new_len, - char *captured, size_t capture_len) -{ - if (new_len >= capture_len) { - memcpy(captured, new_msgs + (new_len - capture_len), - capture_len); - return capture_len; - } else { - /* Grab the end of old_msgs. */ - size_t old_tail_len = min(old_len, capture_len - new_len); - memcpy(captured, old_msgs + (old_len - old_tail_len), - old_tail_len); - memcpy(captured + old_tail_len, new_msgs, new_len); - return old_tail_len + new_len; - } -} - /* * Are we using the ibm,rtas-log for oops/panic reports? And if so, * would logging this oops/panic overwrite an RTAS event that rtas_errd @@ -541,27 +517,6 @@ static int clobbering_unread_rtas_event(void) NVRAM_RTAS_READ_TIMEOUT); } -/* Squeeze out each line's severity prefix. */ -static size_t elide_severities(char *buf, size_t len) -{ - char *in, *out, *buf_end = buf + len; - /* Assume a at the very beginning marks the start of a line. */ - int newline = 1; - - in = out = buf; - while (in < buf_end) { - if (newline && in+3 <= buf_end && - *in == '<' && isdigit(in[1]) && in[2] == '>') { - in += 3; - newline = 0; - } else { - newline = (*in == '\n'); - *out++ = *in++; - } - } - return out - buf; -} - /* Derived from logfs_compress() */ static int nvram_compress(const void *in, void *out, size_t inlen, size_t outlen) @@ -619,9 +574,7 @@ static int zip_oops(size_t text_len) * partition. If that's too much, go back and capture uncompressed text. */ static void oops_to_nvram(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, - const char *old_msgs, unsigned long old_len, - const char *new_msgs, unsigned long new_len) + enum kmsg_dump_reason reason) { static unsigned int oops_count = 0; static bool panicking = false; @@ -660,14 +613,14 @@ static void oops_to_nvram(struct kmsg_dumper *dumper, return; if (big_oops_buf) { - text_len = capture_last_msgs(old_msgs, old_len, - new_msgs, new_len, big_oops_buf, big_oops_buf_sz); - text_len = elide_severities(big_oops_buf, text_len); + kmsg_dump_get_buffer(dumper, false, + big_oops_buf, big_oops_buf_sz, &text_len); rc = zip_oops(text_len); } if (rc != 0) { - text_len = capture_last_msgs(old_msgs, old_len, - new_msgs, new_len, oops_data, oops_data_sz); + kmsg_dump_rewind(dumper); + kmsg_dump_get_buffer(dumper, true, + oops_data, oops_data_sz, &text_len); err_type = ERR_TYPE_KERNEL_PANIC; *oops_len = (u16) text_len; } diff --git a/arch/x86/platform/mrst/early_printk_mrst.c b/arch/x86/platform/mrst/early_printk_mrst.c index 3c6e328483c7..028454f0c3a5 100644 --- a/arch/x86/platform/mrst/early_printk_mrst.c +++ b/arch/x86/platform/mrst/early_printk_mrst.c @@ -110,19 +110,16 @@ static struct kmsg_dumper dw_dumper; static int dumper_registered; static void dw_kmsg_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, - const char *s1, unsigned long l1, - const char *s2, unsigned long l2) + enum kmsg_dump_reason reason) { - int i; + static char line[1024]; + size_t len; /* When run to this, we'd better re-init the HW */ mrst_early_console_init(); - for (i = 0; i < l1; i++) - early_mrst_console.write(&early_mrst_console, s1 + i, 1); - for (i = 0; i < l2; i++) - early_mrst_console.write(&early_mrst_console, s2 + i, 1); + while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) + early_mrst_console.write(&early_mrst_console, line, len); } /* Set the ratio rate to 115200, 8n1, IRQ disabled */ diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index ae36d7e1e913..551e316e4454 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -304,32 +304,17 @@ static void find_next_position(struct mtdoops_context *cxt) } static void mtdoops_do_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, const char *s1, unsigned long l1, - const char *s2, unsigned long l2) + enum kmsg_dump_reason reason) { struct mtdoops_context *cxt = container_of(dumper, struct mtdoops_context, dump); - unsigned long s1_start, s2_start; - unsigned long l1_cpy, l2_cpy; - char *dst; - - if (reason != KMSG_DUMP_OOPS && - reason != KMSG_DUMP_PANIC) - return; /* Only dump oopses if dump_oops is set */ if (reason == KMSG_DUMP_OOPS && !dump_oops) return; - dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */ - l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE); - l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy); - - s2_start = l2 - l2_cpy; - s1_start = l1 - l1_cpy; - - memcpy(dst, s1 + s1_start, l1_cpy); - memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); + kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE, + record_size - MTDOOPS_HEADER_SIZE, NULL); /* Panics must be written immediately */ if (reason != KMSG_DUMP_OOPS) @@ -375,6 +360,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd) return; } + cxt->dump.max_reason = KMSG_DUMP_OOPS; cxt->dump.dump = mtdoops_do_dump; err = kmsg_dump_register(&cxt->dump); if (err) { diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 82c585f715e3..03ce7a9b81cc 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -94,20 +94,15 @@ static const char *get_reason_str(enum kmsg_dump_reason reason) * as we can from the end of the buffer. */ static void pstore_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, - const char *s1, unsigned long l1, - const char *s2, unsigned long l2) + enum kmsg_dump_reason reason) { - unsigned long s1_start, s2_start; - unsigned long l1_cpy, l2_cpy; - unsigned long size, total = 0; - char *dst; + unsigned long total = 0; const char *why; u64 id; - int hsize, ret; unsigned int part = 1; unsigned long flags = 0; int is_locked = 0; + int ret; why = get_reason_str(reason); @@ -119,30 +114,25 @@ static void pstore_dump(struct kmsg_dumper *dumper, spin_lock_irqsave(&psinfo->buf_lock, flags); oopscount++; while (total < kmsg_bytes) { + char *dst; + unsigned long size; + int hsize; + size_t len; + dst = psinfo->buf; hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); size = psinfo->bufsize - hsize; dst += hsize; - l2_cpy = min(l2, size); - l1_cpy = min(l1, size - l2_cpy); - - if (l1_cpy + l2_cpy == 0) + if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len)) break; - s2_start = l2 - l2_cpy; - s1_start = l1 - l1_cpy; - - memcpy(dst, s1 + s1_start, l1_cpy); - memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); - ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part, - hsize + l1_cpy + l2_cpy, psinfo); + hsize + len, psinfo); if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted()) pstore_new_entry = 1; - l1 -= l1_cpy; - l2 -= l2_cpy; - total += l1_cpy + l2_cpy; + + total += hsize + len; part++; } if (in_nmi()) { diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h index 35f7237ec972..af4eb5a39d9a 100644 --- a/include/linux/kmsg_dump.h +++ b/include/linux/kmsg_dump.h @@ -21,6 +21,7 @@ * is passed to the kernel. */ enum kmsg_dump_reason { + KMSG_DUMP_UNDEF, KMSG_DUMP_PANIC, KMSG_DUMP_OOPS, KMSG_DUMP_EMERG, @@ -31,23 +32,37 @@ enum kmsg_dump_reason { /** * struct kmsg_dumper - kernel crash message dumper structure - * @dump: The callback which gets called on crashes. The buffer is passed - * as two sections, where s1 (length l1) contains the older - * messages and s2 (length l2) contains the newer. * @list: Entry in the dumper list (private) + * @dump: Call into dumping code which will retrieve the data with + * through the record iterator + * @max_reason: filter for highest reason number that should be dumped * @registered: Flag that specifies if this is already registered */ struct kmsg_dumper { - void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason, - const char *s1, unsigned long l1, - const char *s2, unsigned long l2); struct list_head list; - int registered; + void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason); + enum kmsg_dump_reason max_reason; + bool active; + bool registered; + + /* private state of the kmsg iterator */ + u32 cur_idx; + u32 next_idx; + u64 cur_seq; + u64 next_seq; }; #ifdef CONFIG_PRINTK void kmsg_dump(enum kmsg_dump_reason reason); +bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, + char *line, size_t size, size_t *len); + +bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, + char *buf, size_t size, size_t *len); + +void kmsg_dump_rewind(struct kmsg_dumper *dumper); + int kmsg_dump_register(struct kmsg_dumper *dumper); int kmsg_dump_unregister(struct kmsg_dumper *dumper); @@ -56,6 +71,22 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason) { } +bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, + const char *line, size_t size, size_t *len) +{ + return false; +} + +bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, + char *buf, size_t size, size_t *len) +{ + return false; +} + +void kmsg_dump_rewind(struct kmsg_dumper *dumper) +{ +} + static inline int kmsg_dump_register(struct kmsg_dumper *dumper) { return -EINVAL; diff --git a/kernel/printk.c b/kernel/printk.c index f205c25c37e2..ceb4a2f775a1 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -909,7 +909,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear) /* * Find first record that fits, including all following records, * into the user-provided buffer for this dump. - */ + */ seq = clear_seq; idx = clear_idx; while (seq < log_next_seq) { @@ -919,6 +919,8 @@ static int syslog_print_all(char __user *buf, int size, bool clear) idx = log_next(idx); seq++; } + + /* move first record forward until length fits into the buffer */ seq = clear_seq; idx = clear_idx; while (len > size && seq < log_next_seq) { @@ -929,7 +931,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear) seq++; } - /* last message in this dump */ + /* last message fitting into this dump */ next_seq = log_next_seq; len = 0; @@ -2300,48 +2302,210 @@ module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); * kmsg_dump - dump kernel log to kernel message dumpers. * @reason: the reason (oops, panic etc) for dumping * - * Iterate through each of the dump devices and call the oops/panic - * callbacks with the log buffer. + * Call each of the registered dumper's dump() callback, which can + * retrieve the kmsg records with kmsg_dump_get_line() or + * kmsg_dump_get_buffer(). */ void kmsg_dump(enum kmsg_dump_reason reason) { - u64 idx; struct kmsg_dumper *dumper; - const char *s1, *s2; - unsigned long l1, l2; unsigned long flags; if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) return; - /* Theoretically, the log could move on after we do this, but - there's not a lot we can do about that. The new messages - will overwrite the start of what we dump. */ + rcu_read_lock(); + list_for_each_entry_rcu(dumper, &dump_list, list) { + if (dumper->max_reason && reason > dumper->max_reason) + continue; + + /* initialize iterator with data about the stored records */ + dumper->active = true; + + raw_spin_lock_irqsave(&logbuf_lock, flags); + dumper->cur_seq = clear_seq; + dumper->cur_idx = clear_idx; + dumper->next_seq = log_next_seq; + dumper->next_idx = log_next_idx; + raw_spin_unlock_irqrestore(&logbuf_lock, flags); + + /* invoke dumper which will iterate over records */ + dumper->dump(dumper, reason); + + /* reset iterator */ + dumper->active = false; + } + rcu_read_unlock(); +} + +/** + * kmsg_dump_get_line - retrieve one kmsg log line + * @dumper: registered kmsg dumper + * @syslog: include the "<4>" prefixes + * @line: buffer to copy the line to + * @size: maximum size of the buffer + * @len: length of line placed into buffer + * + * Start at the beginning of the kmsg buffer, with the oldest kmsg + * record, and copy one record into the provided buffer. + * + * Consecutive calls will return the next available record moving + * towards the end of the buffer with the youngest messages. + * + * A return value of FALSE indicates that there are no more records to + * read. + */ +bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, + char *line, size_t size, size_t *len) +{ + unsigned long flags; + struct log *msg; + size_t l = 0; + bool ret = false; + + if (!dumper->active) + goto out; raw_spin_lock_irqsave(&logbuf_lock, flags); - if (syslog_seq < log_first_seq) - idx = syslog_idx; - else - idx = log_first_idx; + if (dumper->cur_seq < log_first_seq) { + /* messages are gone, move to first available one */ + dumper->cur_seq = log_first_seq; + dumper->cur_idx = log_first_idx; + } - if (idx > log_next_idx) { - s1 = log_buf; - l1 = log_next_idx; + /* last entry */ + if (dumper->cur_seq >= log_next_seq) { + raw_spin_unlock_irqrestore(&logbuf_lock, flags); + goto out; + } - s2 = log_buf + idx; - l2 = log_buf_len - idx; - } else { - s1 = ""; - l1 = 0; + msg = log_from_idx(dumper->cur_idx); + l = msg_print_text(msg, syslog, + line, size); + + dumper->cur_idx = log_next(dumper->cur_idx); + dumper->cur_seq++; + ret = true; + raw_spin_unlock_irqrestore(&logbuf_lock, flags); +out: + if (len) + *len = l; + return ret; +} +EXPORT_SYMBOL_GPL(kmsg_dump_get_line); + +/** + * kmsg_dump_get_buffer - copy kmsg log lines + * @dumper: registered kmsg dumper + * @syslog: include the "<4>" prefixes + * @line: buffer to copy the line to + * @size: maximum size of the buffer + * @len: length of line placed into buffer + * + * Start at the end of the kmsg buffer and fill the provided buffer + * with as many of the the *youngest* kmsg records that fit into it. + * If the buffer is large enough, all available kmsg records will be + * copied with a single call. + * + * Consecutive calls will fill the buffer with the next block of + * available older records, not including the earlier retrieved ones. + * + * A return value of FALSE indicates that there are no more records to + * read. + */ +bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, + char *buf, size_t size, size_t *len) +{ + unsigned long flags; + u64 seq; + u32 idx; + u64 next_seq; + u32 next_idx; + size_t l = 0; + bool ret = false; + + if (!dumper->active) + goto out; + + raw_spin_lock_irqsave(&logbuf_lock, flags); + if (dumper->cur_seq < log_first_seq) { + /* messages are gone, move to first available one */ + dumper->cur_seq = log_first_seq; + dumper->cur_idx = log_first_idx; + } + + /* last entry */ + if (dumper->cur_seq >= dumper->next_seq) { + raw_spin_unlock_irqrestore(&logbuf_lock, flags); + goto out; + } + + /* calculate length of entire buffer */ + seq = dumper->cur_seq; + idx = dumper->cur_idx; + while (seq < dumper->next_seq) { + struct log *msg = log_from_idx(idx); + + l += msg_print_text(msg, true, NULL, 0); + idx = log_next(idx); + seq++; + } + + /* move first record forward until length fits into the buffer */ + seq = dumper->cur_seq; + idx = dumper->cur_idx; + while (l > size && seq < dumper->next_seq) { + struct log *msg = log_from_idx(idx); - s2 = log_buf + idx; - l2 = log_next_idx - idx; + l -= msg_print_text(msg, true, NULL, 0); + idx = log_next(idx); + seq++; } + + /* last message in next interation */ + next_seq = seq; + next_idx = idx; + + l = 0; + while (seq < dumper->next_seq) { + struct log *msg = log_from_idx(idx); + + l += msg_print_text(msg, syslog, + buf + l, size - l); + + idx = log_next(idx); + seq++; + } + + dumper->next_seq = next_seq; + dumper->next_idx = next_idx; + ret = true; raw_spin_unlock_irqrestore(&logbuf_lock, flags); +out: + if (len) + *len = l; + return ret; +} +EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); - rcu_read_lock(); - list_for_each_entry_rcu(dumper, &dump_list, list) - dumper->dump(dumper, reason, s1, l1, s2, l2); - rcu_read_unlock(); +/** + * kmsg_dump_rewind - reset the interator + * @dumper: registered kmsg dumper + * + * Reset the dumper's iterator so that kmsg_dump_get_line() and + * kmsg_dump_get_buffer() can be called again and used multiple + * times within the same dumper.dump() callback. + */ +void kmsg_dump_rewind(struct kmsg_dumper *dumper) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&logbuf_lock, flags); + dumper->cur_seq = clear_seq; + dumper->cur_idx = clear_idx; + dumper->next_seq = log_next_seq; + dumper->next_idx = log_next_idx; + raw_spin_unlock_irqrestore(&logbuf_lock, flags); } +EXPORT_SYMBOL_GPL(kmsg_dump_rewind); #endif -- cgit v1.2.3