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Diffstat (limited to 'src/kbuffer-parse.c')
| -rw-r--r-- | src/kbuffer-parse.c | 848 |
1 files changed, 848 insertions, 0 deletions
diff --git a/src/kbuffer-parse.c b/src/kbuffer-parse.c new file mode 100644 index 0000000..390a789 --- /dev/null +++ b/src/kbuffer-parse.c @@ -0,0 +1,848 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (C) 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> + * + */ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <stdbool.h> + +#include <sys/utsname.h> + +#include "kbuffer.h" + +#define MISSING_EVENTS (1UL << 31) +#define MISSING_STORED (1UL << 30) + +#define COMMIT_MASK ((1 << 27) - 1) + +/* Absolute time stamps do not have the 5 MSB, take from the real time stamp */ +#define TS_MSB (0xf8ULL << 56) + +enum { + KBUFFER_FL_HOST_BIG_ENDIAN = (1<<0), + KBUFFER_FL_BIG_ENDIAN = (1<<1), + KBUFFER_FL_LONG_8 = (1<<2), + KBUFFER_FL_OLD_FORMAT = (1<<3), +}; + +#define ENDIAN_MASK (KBUFFER_FL_HOST_BIG_ENDIAN | KBUFFER_FL_BIG_ENDIAN) + +/** kbuffer + * @timestamp - timestamp of current event + * @lost_events - # of lost events between this subbuffer and previous + * @flags - special flags of the kbuffer + * @subbuffer - pointer to the sub-buffer page + * @data - pointer to the start of data on the sub-buffer page + * @index - index from @data to the @curr event data + * @curr - offset from @data to the start of current event + * (includes metadata) + * @next - offset from @data to the start of next event + * @size - The size of data on @data + * @start - The offset from @subbuffer where @data lives + * @first - The offset from @subbuffer where the first non time stamp event lives + * + * @read_4 - Function to read 4 raw bytes (may swap) + * @read_8 - Function to read 8 raw bytes (may swap) + * @read_long - Function to read a long word (4 or 8 bytes with needed swap) + */ +struct kbuffer { + unsigned long long timestamp; + long long lost_events; + unsigned long flags; + void *subbuffer; + void *data; + unsigned int index; + unsigned int curr; + unsigned int next; + unsigned int size; + unsigned int start; + unsigned int first; + + unsigned int (*read_4)(void *ptr); + unsigned long long (*read_8)(void *ptr); + unsigned long long (*read_long)(struct kbuffer *kbuf, void *ptr); + int (*next_event)(struct kbuffer *kbuf); +}; + +static void *zmalloc(size_t size) +{ + return calloc(1, size); +} + +static int host_is_bigendian(void) +{ + unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 }; + unsigned int *ptr; + + ptr = (unsigned int *)str; + return *ptr == 0x01020304; +} + +static int do_swap(struct kbuffer *kbuf) +{ + return ((kbuf->flags & KBUFFER_FL_HOST_BIG_ENDIAN) + kbuf->flags) & + ENDIAN_MASK; +} + +static unsigned long long __read_8(void *ptr) +{ + unsigned long long data = *(unsigned long long *)ptr; + + return data; +} + +static unsigned long long __read_8_sw(void *ptr) +{ + unsigned long long data = *(unsigned long long *)ptr; + unsigned long long swap; + + swap = ((data & 0xffULL) << 56) | + ((data & (0xffULL << 8)) << 40) | + ((data & (0xffULL << 16)) << 24) | + ((data & (0xffULL << 24)) << 8) | + ((data & (0xffULL << 32)) >> 8) | + ((data & (0xffULL << 40)) >> 24) | + ((data & (0xffULL << 48)) >> 40) | + ((data & (0xffULL << 56)) >> 56); + + return swap; +} + +static unsigned int __read_4(void *ptr) +{ + unsigned int data = *(unsigned int *)ptr; + + return data; +} + +static unsigned int __read_4_sw(void *ptr) +{ + unsigned int data = *(unsigned int *)ptr; + unsigned int swap; + + swap = ((data & 0xffULL) << 24) | + ((data & (0xffULL << 8)) << 8) | + ((data & (0xffULL << 16)) >> 8) | + ((data & (0xffULL << 24)) >> 24); + + return swap; +} + +static unsigned long long read_8(struct kbuffer *kbuf, void *ptr) +{ + return kbuf->read_8(ptr); +} + +static unsigned int read_4(struct kbuffer *kbuf, void *ptr) +{ + return kbuf->read_4(ptr); +} + +static unsigned long long __read_long_8(struct kbuffer *kbuf, void *ptr) +{ + return kbuf->read_8(ptr); +} + +static unsigned long long __read_long_4(struct kbuffer *kbuf, void *ptr) +{ + return kbuf->read_4(ptr); +} + +static unsigned long long read_long(struct kbuffer *kbuf, void *ptr) +{ + return kbuf->read_long(kbuf, ptr); +} + +static int calc_index(struct kbuffer *kbuf, void *ptr) +{ + return (unsigned long)ptr - (unsigned long)kbuf->data; +} + +static int __next_event(struct kbuffer *kbuf); + +/* + * Just because sizeof(long) is 4 bytes, doesn't mean the OS isn't + * 64bits + */ +static bool host_is_32bit(void) +{ + struct utsname buf; + int ret; + + ret = uname(&buf); + if (ret < 0) { + /* Oh well, just assume it is 32 bit */ + return true; + } + /* If the uname machine value contains 64, assume the kernel is 64 bit */ + return strstr(buf.machine, "64") == NULL; +} + +/** + * kbuffer_alloc - allocat a new kbuffer + * @size; enum to denote size of word + * @endian: enum to denote endianness + * + * Allocates and returns a new kbuffer. + */ +struct kbuffer * +kbuffer_alloc(enum kbuffer_long_size size, enum kbuffer_endian endian) +{ + struct kbuffer *kbuf; + int flags = 0; + + switch (size) { + case KBUFFER_LSIZE_4: + break; + case KBUFFER_LSIZE_SAME_AS_HOST: + if (sizeof(long) != 8 && host_is_32bit()) + break; + /* fallthrough */ + case KBUFFER_LSIZE_8: + flags |= KBUFFER_FL_LONG_8; + break; + default: + return NULL; + } + + switch (endian) { + case KBUFFER_ENDIAN_LITTLE: + case KBUFFER_ENDIAN_SAME_AS_HOST: + break; + case KBUFFER_ENDIAN_BIG: + flags |= KBUFFER_FL_BIG_ENDIAN; + break; + default: + return NULL; + } + + kbuf = zmalloc(sizeof(*kbuf)); + if (!kbuf) + return NULL; + + kbuf->flags = flags; + + if (host_is_bigendian()) { + if (endian == KBUFFER_ENDIAN_SAME_AS_HOST) + flags |= KBUFFER_FL_BIG_ENDIAN; + kbuf->flags |= KBUFFER_FL_HOST_BIG_ENDIAN; + } + + if (do_swap(kbuf)) { + kbuf->read_8 = __read_8_sw; + kbuf->read_4 = __read_4_sw; + } else { + kbuf->read_8 = __read_8; + kbuf->read_4 = __read_4; + } + + if (kbuf->flags & KBUFFER_FL_LONG_8) + kbuf->read_long = __read_long_8; + else + kbuf->read_long = __read_long_4; + + /* May be changed by kbuffer_set_old_format() */ + kbuf->next_event = __next_event; + + return kbuf; +} + +/** kbuffer_free - free an allocated kbuffer + * @kbuf: The kbuffer to free + * + * Can take NULL as a parameter. + */ +void kbuffer_free(struct kbuffer *kbuf) +{ + free(kbuf); +} + +static unsigned int type4host(struct kbuffer *kbuf, + unsigned int type_len_ts) +{ + if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN) + return (type_len_ts >> 29) & 3; + else + return type_len_ts & 3; +} + +static unsigned int len4host(struct kbuffer *kbuf, + unsigned int type_len_ts) +{ + if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN) + return (type_len_ts >> 27) & 7; + else + return (type_len_ts >> 2) & 7; +} + +static unsigned int type_len4host(struct kbuffer *kbuf, + unsigned int type_len_ts) +{ + if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN) + return (type_len_ts >> 27) & ((1 << 5) - 1); + else + return type_len_ts & ((1 << 5) - 1); +} + +static unsigned int ts4host(struct kbuffer *kbuf, + unsigned int type_len_ts) +{ + if (kbuf->flags & KBUFFER_FL_BIG_ENDIAN) + return type_len_ts & ((1 << 27) - 1); + else + return type_len_ts >> 5; +} + +/* + * Linux 2.6.30 and earlier (not much ealier) had a different + * ring buffer format. It should be obsolete, but we handle it anyway. + */ +enum old_ring_buffer_type { + OLD_RINGBUF_TYPE_PADDING, + OLD_RINGBUF_TYPE_TIME_EXTEND, + OLD_RINGBUF_TYPE_TIME_STAMP, + OLD_RINGBUF_TYPE_DATA, +}; + +static unsigned int old_update_pointers(struct kbuffer *kbuf) +{ + unsigned long long extend; + unsigned int type_len_ts; + unsigned int type; + unsigned int len; + unsigned int delta; + unsigned int length; + void *ptr = kbuf->data + kbuf->curr; + + type_len_ts = read_4(kbuf, ptr); + ptr += 4; + + type = type4host(kbuf, type_len_ts); + len = len4host(kbuf, type_len_ts); + delta = ts4host(kbuf, type_len_ts); + + switch (type) { + case OLD_RINGBUF_TYPE_PADDING: + kbuf->next = kbuf->size; + return 0; + + case OLD_RINGBUF_TYPE_TIME_EXTEND: + extend = read_4(kbuf, ptr); + extend <<= TS_SHIFT; + extend += delta; + delta = extend; + ptr += 4; + length = 0; + break; + + case OLD_RINGBUF_TYPE_TIME_STAMP: + /* should never happen! */ + kbuf->curr = kbuf->size; + kbuf->next = kbuf->size; + kbuf->index = kbuf->size; + return -1; + default: + if (len) + length = len * 4; + else { + length = read_4(kbuf, ptr); + length -= 4; + ptr += 4; + } + break; + } + + kbuf->timestamp += delta; + kbuf->index = calc_index(kbuf, ptr); + kbuf->next = kbuf->index + length; + + return type; +} + +static int __old_next_event(struct kbuffer *kbuf) +{ + int type; + + do { + kbuf->curr = kbuf->next; + if (kbuf->next >= kbuf->size) + return -1; + type = old_update_pointers(kbuf); + } while (type == OLD_RINGBUF_TYPE_TIME_EXTEND || type == OLD_RINGBUF_TYPE_PADDING); + + return 0; +} + +static unsigned int +translate_data(struct kbuffer *kbuf, void *data, void **rptr, + unsigned long long *delta, int *length) +{ + unsigned long long extend, msb = 0; + unsigned int type_len_ts; + unsigned int type_len; + + type_len_ts = read_4(kbuf, data); + data += 4; + + type_len = type_len4host(kbuf, type_len_ts); + *delta = ts4host(kbuf, type_len_ts); + + switch (type_len) { + case KBUFFER_TYPE_PADDING: + *length = read_4(kbuf, data); + break; + + case KBUFFER_TYPE_TIME_STAMP: + msb = kbuf->timestamp & TS_MSB; + /* fall through */ + case KBUFFER_TYPE_TIME_EXTEND: + extend = read_4(kbuf, data); + data += 4; + extend <<= TS_SHIFT; + extend += *delta; + *delta = extend | msb; + *length = 0; + break; + + case 0: + *length = read_4(kbuf, data) - 4; + *length = (*length + 3) & ~3; + data += 4; + break; + default: + *length = type_len * 4; + break; + } + + *rptr = data; + + return type_len; +} + +static unsigned int update_pointers(struct kbuffer *kbuf) +{ + unsigned long long delta; + unsigned int type_len; + int length; + void *ptr = kbuf->data + kbuf->curr; + + type_len = translate_data(kbuf, ptr, &ptr, &delta, &length); + + if (type_len == KBUFFER_TYPE_TIME_STAMP) + kbuf->timestamp = delta; + else + kbuf->timestamp += delta; + + kbuf->index = calc_index(kbuf, ptr); + kbuf->next = kbuf->index + length; + + return type_len; +} + +/** + * kbuffer_translate_data - read raw data to get a record + * @swap: Set to 1 if bytes in words need to be swapped when read + * @data: The raw data to read + * @size: Address to store the size of the event data. + * + * Returns a pointer to the event data. To determine the entire + * record size (record metadata + data) just add the difference between + * @data and the returned value to @size. + */ +void *kbuffer_translate_data(int swap, void *data, unsigned int *size) +{ + unsigned long long delta; + struct kbuffer kbuf; + int type_len; + int length; + void *ptr; + + if (swap) { + kbuf.read_8 = __read_8_sw; + kbuf.read_4 = __read_4_sw; + kbuf.flags = host_is_bigendian() ? 0 : KBUFFER_FL_BIG_ENDIAN; + } else { + kbuf.read_8 = __read_8; + kbuf.read_4 = __read_4; + kbuf.flags = host_is_bigendian() ? KBUFFER_FL_BIG_ENDIAN: 0; + } + + type_len = translate_data(&kbuf, data, &ptr, &delta, &length); + switch (type_len) { + case KBUFFER_TYPE_PADDING: + case KBUFFER_TYPE_TIME_EXTEND: + case KBUFFER_TYPE_TIME_STAMP: + return NULL; + } + + *size = length; + + return ptr; +} + +static int __next_event(struct kbuffer *kbuf) +{ + int type; + + do { + kbuf->curr = kbuf->next; + if (kbuf->next >= kbuf->size) + return -1; + type = update_pointers(kbuf); + } while (type == KBUFFER_TYPE_TIME_EXTEND || + type == KBUFFER_TYPE_TIME_STAMP || + type == KBUFFER_TYPE_PADDING); + + return 0; +} + +static int next_event(struct kbuffer *kbuf) +{ + return kbuf->next_event(kbuf); +} + +/** + * kbuffer_next_event - increment the current pointer + * @kbuf: The kbuffer to read + * @ts: Address to store the next record's timestamp (may be NULL to ignore) + * + * Increments the pointers into the subbuffer of the kbuffer to point to the + * next event so that the next kbuffer_read_event() will return a + * new event. + * + * Returns the data of the next event if a new event exists on the subbuffer, + * NULL otherwise. + */ +void *kbuffer_next_event(struct kbuffer *kbuf, unsigned long long *ts) +{ + int ret; + + if (!kbuf || !kbuf->subbuffer) + return NULL; + + ret = next_event(kbuf); + if (ret < 0) + return NULL; + + if (ts) + *ts = kbuf->timestamp; + + return kbuf->data + kbuf->index; +} + +/** + * kbuffer_load_subbuffer - load a new subbuffer into the kbuffer + * @kbuf: The kbuffer to load + * @subbuffer: The subbuffer to load into @kbuf. + * + * Load a new subbuffer (page) into @kbuf. This will reset all + * the pointers and update the @kbuf timestamp. The next read will + * return the first event on @subbuffer. + * + * Returns 0 on succes, -1 otherwise. + */ +int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer) +{ + unsigned long long flags; + void *ptr = subbuffer; + + if (!kbuf || !subbuffer) + return -1; + + kbuf->subbuffer = subbuffer; + + kbuf->timestamp = read_8(kbuf, ptr); + ptr += 8; + + kbuf->curr = 0; + + if (kbuf->flags & KBUFFER_FL_LONG_8) + kbuf->start = 16; + else + kbuf->start = 12; + + kbuf->data = subbuffer + kbuf->start; + + flags = read_long(kbuf, ptr); + kbuf->size = (unsigned int)flags & COMMIT_MASK; + + if (flags & MISSING_EVENTS) { + if (flags & MISSING_STORED) { + ptr = kbuf->data + kbuf->size; + kbuf->lost_events = read_long(kbuf, ptr); + } else + kbuf->lost_events = -1; + } else + kbuf->lost_events = 0; + + kbuf->index = 0; + kbuf->next = 0; + + next_event(kbuf); + + /* save the first record from the page */ + kbuf->first = kbuf->curr; + + return 0; +} + +/** + * kbuffer_subbuf_timestamp - read the timestamp from a sub buffer + * @kbuf: The kbuffer to load + * @subbuf: The subbuffer to read from. + * + * Return the timestamp from a subbuffer. + */ +unsigned long long kbuffer_subbuf_timestamp(struct kbuffer *kbuf, void *subbuf) +{ + return kbuf->read_8(subbuf); +} + +/** + * kbuffer_ptr_delta - read the delta field from a record + * @kbuf: The kbuffer to load + * @ptr: The record in the buffe. + * + * Return the timestamp delta from a record + */ +unsigned int kbuffer_ptr_delta(struct kbuffer *kbuf, void *ptr) +{ + unsigned int type_len_ts; + + type_len_ts = read_4(kbuf, ptr); + return ts4host(kbuf, type_len_ts); +} + + +/** + * kbuffer_read_event - read the next event in the kbuffer subbuffer + * @kbuf: The kbuffer to read from + * @ts: The address to store the timestamp of the event (may be NULL to ignore) + * + * Returns a pointer to the data part of the current event. + * NULL if no event is left on the subbuffer. + */ +void *kbuffer_read_event(struct kbuffer *kbuf, unsigned long long *ts) +{ + if (!kbuf || !kbuf->subbuffer) + return NULL; + + if (kbuf->curr >= kbuf->size) + return NULL; + + if (ts) + *ts = kbuf->timestamp; + return kbuf->data + kbuf->index; +} + +/** + * kbuffer_timestamp - Return the timestamp of the current event + * @kbuf: The kbuffer to read from + * + * Returns the timestamp of the current (next) event. + */ +unsigned long long kbuffer_timestamp(struct kbuffer *kbuf) +{ + return kbuf->timestamp; +} + +/** + * kbuffer_read_at_offset - read the event that is at offset + * @kbuf: The kbuffer to read from + * @offset: The offset into the subbuffer + * @ts: The address to store the timestamp of the event (may be NULL to ignore) + * + * The @offset must be an index from the @kbuf subbuffer beginning. + * If @offset is bigger than the stored subbuffer, NULL will be returned. + * + * Returns the data of the record that is at @offset. Note, @offset does + * not need to be the start of the record, the offset just needs to be + * in the record (or beginning of it). + * + * Note, the kbuf timestamp and pointers are updated to the + * returned record. That is, kbuffer_read_event() will return the same + * data and timestamp, and kbuffer_next_event() will increment from + * this record. + */ +void *kbuffer_read_at_offset(struct kbuffer *kbuf, int offset, + unsigned long long *ts) +{ + void *data; + + if (offset < kbuf->start) + offset = 0; + else + offset -= kbuf->start; + + /* Reset the buffer */ + kbuffer_load_subbuffer(kbuf, kbuf->subbuffer); + data = kbuffer_read_event(kbuf, ts); + + while (kbuf->curr < offset) { + data = kbuffer_next_event(kbuf, ts); + if (!data) + break; + } + + return data; +} + +/** + * kbuffer_subbuffer_size - the size of the loaded subbuffer + * @kbuf: The kbuffer to read from + * + * Returns the size of the subbuffer. Note, this size is + * where the last event resides. The stored subbuffer may actually be + * bigger due to padding and such. + */ +int kbuffer_subbuffer_size(struct kbuffer *kbuf) +{ + return kbuf->size; +} + +/** + * kbuffer_curr_index - Return the index of the record + * @kbuf: The kbuffer to read from + * + * Returns the index from the start of the data part of + * the subbuffer to the current location. Note this is not + * from the start of the subbuffer. An index of zero will + * point to the first record. Use kbuffer_curr_offset() for + * the actually offset (that can be used by kbuffer_read_at_offset()) + */ +int kbuffer_curr_index(struct kbuffer *kbuf) +{ + return kbuf->curr; +} + +/** + * kbuffer_curr_offset - Return the offset of the record + * @kbuf: The kbuffer to read from + * + * Returns the offset from the start of the subbuffer to the + * current location. + */ +int kbuffer_curr_offset(struct kbuffer *kbuf) +{ + return kbuf->curr + kbuf->start; +} + +/** + * kbuffer_event_size - return the size of the event data + * @kbuf: The kbuffer to read + * + * Returns the size of the event data (the payload not counting + * the meta data of the record) of the current event. + */ +int kbuffer_event_size(struct kbuffer *kbuf) +{ + return kbuf->next - kbuf->index; +} + +/** + * kbuffer_curr_size - return the size of the entire record + * @kbuf: The kbuffer to read + * + * Returns the size of the entire record (meta data and payload) + * of the current event. + */ +int kbuffer_curr_size(struct kbuffer *kbuf) +{ + return kbuf->next - kbuf->curr; +} + +/** + * kbuffer_missed_events - return the # of missed events from last event. + * @kbuf: The kbuffer to read from + * + * Returns the # of missed events (if recorded) before the current + * event. Note, only events on the beginning of a subbuffer can + * have missed events, all other events within the buffer will be + * zero. + */ +int kbuffer_missed_events(struct kbuffer *kbuf) +{ + /* Only the first event can have missed events */ + if (kbuf->curr) + return 0; + + return kbuf->lost_events; +} + +/** + * kbuffer_set_old_forma - set the kbuffer to use the old format parsing + * @kbuf: The kbuffer to set + * + * This is obsolete (or should be). The first kernels to use the + * new ring buffer had a slightly different ring buffer format + * (2.6.30 and earlier). It is still somewhat supported by kbuffer, + * but should not be counted on in the future. + */ +void kbuffer_set_old_format(struct kbuffer *kbuf) +{ + kbuf->flags |= KBUFFER_FL_OLD_FORMAT; + + kbuf->next_event = __old_next_event; +} + +/** + * kbuffer_start_of_data - return offset of where data starts on subbuffer + * @kbuf: The kbuffer + * + * Returns the location on the subbuffer where the data starts. + */ +int kbuffer_start_of_data(struct kbuffer *kbuf) +{ + return kbuf->first + kbuf->start; +} + +/** + * kbuffer_raw_get - get raw buffer info + * @kbuf: The kbuffer + * @subbuf: Start of mapped subbuffer + * @info: Info descriptor to fill in + * + * For debugging. This can return internals of the ring buffer. + * Expects to have info->next set to what it will read. + * The type, length and timestamp delta will be filled in, and + * @info->next will be updated to the next element. + * The @subbuf is used to know if the info is passed the end of + * data and NULL will be returned if it is. + */ +struct kbuffer_raw_info * +kbuffer_raw_get(struct kbuffer *kbuf, void *subbuf, struct kbuffer_raw_info *info) +{ + unsigned long long flags; + unsigned long long delta; + unsigned int type_len; + unsigned int size; + int start; + int length; + void *ptr = info->next; + + if (!kbuf || !subbuf) + return NULL; + + if (kbuf->flags & KBUFFER_FL_LONG_8) + start = 16; + else + start = 12; + + flags = read_long(kbuf, subbuf + 8); + size = (unsigned int)flags & COMMIT_MASK; + + if (ptr < subbuf || ptr >= subbuf + start + size) + return NULL; + + type_len = translate_data(kbuf, ptr, &ptr, &delta, &length); + + info->next = ptr + length; + + info->type = type_len; + info->delta = delta; + info->length = length; + + return info; +} |