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android_system_core/liblog/pmsg_reader.cpp
Tom Cherry 441054aa1e Remove old logger_entry_v* formats 
logger_entry and logger_entry_v2 were used for the kernel logger,
which we have long since deprecated.  logger_entry_v3 is the same as
logger_entry_v4 without a uid field, so it is trivially removable,
especially since we're now always providing uids in log messages.

liblog and logd already get updated in sync with each other, so we
have no reason for backwards compatibility with their format.

Test: build, unit tests
Change-Id: I27c90609f28c8d826e5614fdb3fe59bde22b5042
2019-10-24 10:53:14 -07:00

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/*
* Copyright (C) 2007-2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <private/android_filesystem_config.h>
#include <private/android_logger.h>
#include "logger.h"
static int pmsgAvailable(log_id_t logId);
static int pmsgVersion(struct android_log_logger* logger,
struct android_log_transport_context* transp);
static int pmsgRead(struct android_log_logger_list* logger_list,
struct android_log_transport_context* transp, struct log_msg* log_msg);
static void pmsgClose(struct android_log_logger_list* logger_list,
struct android_log_transport_context* transp);
static int pmsgClear(struct android_log_logger* logger,
struct android_log_transport_context* transp);
struct android_log_transport_read pmsgLoggerRead = {
.name = "pmsg",
.available = pmsgAvailable,
.version = pmsgVersion,
.close = pmsgClose,
.read = pmsgRead,
.poll = NULL,
.clear = pmsgClear,
.setSize = NULL,
.getSize = NULL,
.getReadableSize = NULL,
.getPrune = NULL,
.setPrune = NULL,
.getStats = NULL,
};
static int pmsgAvailable(log_id_t logId) {
if (logId > LOG_ID_SECURITY) {
return -EINVAL;
}
if (access("/dev/pmsg0", W_OK) == 0) {
return 0;
}
return -EBADF;
}
static int pmsgClear(struct android_log_logger* logger __unused,
struct android_log_transport_context* transp __unused) {
return unlink("/sys/fs/pstore/pmsg-ramoops-0");
}
/*
* returns the logger version
*/
static int pmsgVersion(struct android_log_logger* logger __unused,
struct android_log_transport_context* transp __unused) {
return 4;
}
static int pmsgRead(struct android_log_logger_list* logger_list,
struct android_log_transport_context* transp, struct log_msg* log_msg) {
ssize_t ret;
off_t current, next;
struct __attribute__((__packed__)) {
android_pmsg_log_header_t p;
android_log_header_t l;
uint8_t prio;
} buf;
static uint8_t preread_count;
memset(log_msg, 0, sizeof(*log_msg));
if (atomic_load(&transp->context.fd) <= 0) {
int i, fd = open("/sys/fs/pstore/pmsg-ramoops-0", O_RDONLY | O_CLOEXEC);
if (fd < 0) {
return -errno;
}
if (fd == 0) { /* Argggg */
fd = open("/sys/fs/pstore/pmsg-ramoops-0", O_RDONLY | O_CLOEXEC);
close(0);
if (fd < 0) {
return -errno;
}
}
i = atomic_exchange(&transp->context.fd, fd);
if ((i > 0) && (i != fd)) {
close(i);
}
preread_count = 0;
}
while (1) {
int fd;
if (preread_count < sizeof(buf)) {
fd = atomic_load(&transp->context.fd);
if (fd <= 0) {
return -EBADF;
}
ret = TEMP_FAILURE_RETRY(read(fd, &buf.p.magic + preread_count, sizeof(buf) - preread_count));
if (ret < 0) {
return -errno;
}
preread_count += ret;
}
if (preread_count != sizeof(buf)) {
return preread_count ? -EIO : -EAGAIN;
}
if ((buf.p.magic != LOGGER_MAGIC) || (buf.p.len <= sizeof(buf)) ||
(buf.p.len > (sizeof(buf) + LOGGER_ENTRY_MAX_PAYLOAD)) || (buf.l.id >= LOG_ID_MAX) ||
(buf.l.realtime.tv_nsec >= NS_PER_SEC) ||
((buf.l.id != LOG_ID_EVENTS) && (buf.l.id != LOG_ID_SECURITY) &&
((buf.prio == ANDROID_LOG_UNKNOWN) || (buf.prio == ANDROID_LOG_DEFAULT) ||
(buf.prio >= ANDROID_LOG_SILENT)))) {
do {
memmove(&buf.p.magic, &buf.p.magic + 1, --preread_count);
} while (preread_count && (buf.p.magic != LOGGER_MAGIC));
continue;
}
preread_count = 0;
if ((transp->logMask & (1 << buf.l.id)) &&
((!logger_list->start.tv_sec && !logger_list->start.tv_nsec) ||
((logger_list->start.tv_sec <= buf.l.realtime.tv_sec) &&
((logger_list->start.tv_sec != buf.l.realtime.tv_sec) ||
(logger_list->start.tv_nsec <= buf.l.realtime.tv_nsec)))) &&
(!logger_list->pid || (logger_list->pid == buf.p.pid))) {
char* msg = log_msg->entry.msg;
*msg = buf.prio;
fd = atomic_load(&transp->context.fd);
if (fd <= 0) {
return -EBADF;
}
ret = TEMP_FAILURE_RETRY(read(fd, msg + sizeof(buf.prio), buf.p.len - sizeof(buf)));
if (ret < 0) {
return -errno;
}
if (ret != (ssize_t)(buf.p.len - sizeof(buf))) {
return -EIO;
}
log_msg->entry.len = buf.p.len - sizeof(buf) + sizeof(buf.prio);
log_msg->entry.hdr_size = sizeof(log_msg->entry);
log_msg->entry.pid = buf.p.pid;
log_msg->entry.tid = buf.l.tid;
log_msg->entry.sec = buf.l.realtime.tv_sec;
log_msg->entry.nsec = buf.l.realtime.tv_nsec;
log_msg->entry.lid = buf.l.id;
log_msg->entry.uid = buf.p.uid;
return ret + sizeof(buf.prio) + log_msg->entry.hdr_size;
}
fd = atomic_load(&transp->context.fd);
if (fd <= 0) {
return -EBADF;
}
current = TEMP_FAILURE_RETRY(lseek(fd, (off_t)0, SEEK_CUR));
if (current < 0) {
return -errno;
}
fd = atomic_load(&transp->context.fd);
if (fd <= 0) {
return -EBADF;
}
next = TEMP_FAILURE_RETRY(lseek(fd, (off_t)(buf.p.len - sizeof(buf)), SEEK_CUR));
if (next < 0) {
return -errno;
}
if ((next - current) != (ssize_t)(buf.p.len - sizeof(buf))) {
return -EIO;
}
}
}
static void pmsgClose(struct android_log_logger_list* logger_list __unused,
struct android_log_transport_context* transp) {
int fd = atomic_exchange(&transp->context.fd, 0);
if (fd > 0) {
close(fd);
}
}
static void* realloc_or_free(void* ptr, size_t new_size) {
void* result = realloc(ptr, new_size);
if (!result) {
free(ptr);
}
return result;
}
ssize_t __android_log_pmsg_file_read(log_id_t logId, char prio, const char* prefix,
__android_log_pmsg_file_read_fn fn, void* arg) {
ssize_t ret;
struct android_log_logger_list logger_list;
struct android_log_transport_context transp;
struct content {
struct listnode node;
struct logger_entry entry;
} * content;
struct names {
struct listnode node;
struct listnode content;
log_id_t id;
char prio;
char name[];
} * names;
struct listnode name_list;
struct listnode *node, *n;
size_t len, prefix_len;
if (!fn) {
return -EINVAL;
}
/* Add just enough clues in logger_list and transp to make API function */
memset(&logger_list, 0, sizeof(logger_list));
memset(&transp, 0, sizeof(transp));
logger_list.mode = ANDROID_LOG_PSTORE | ANDROID_LOG_NONBLOCK | ANDROID_LOG_RDONLY;
transp.logMask = (unsigned)-1;
if (logId != LOG_ID_ANY) {
transp.logMask = (1 << logId);
}
transp.logMask &= ~((1 << LOG_ID_KERNEL) | (1 << LOG_ID_EVENTS) | (1 << LOG_ID_SECURITY));
if (!transp.logMask) {
return -EINVAL;
}
/* Initialize name list */
list_init(&name_list);
ret = SSIZE_MAX;
/* Validate incoming prefix, shift until it contains only 0 or 1 : or / */
prefix_len = 0;
if (prefix) {
const char *prev = NULL, *last = NULL, *cp = prefix;
while ((cp = strpbrk(cp, "/:"))) {
prev = last;
last = cp;
cp = cp + 1;
}
if (prev) {
prefix = prev + 1;
}
prefix_len = strlen(prefix);
}
/* Read the file content */
while (pmsgRead(&logger_list, &transp, &transp.logMsg) > 0) {
const char* cp;
size_t hdr_size = transp.logMsg.entry.hdr_size;
char* msg = (char*)&transp.logMsg + hdr_size;
const char* split = NULL;
if (hdr_size != sizeof(transp.logMsg.entry)) {
continue;
}
/* Check for invalid sequence number */
if ((transp.logMsg.entry.nsec % ANDROID_LOG_PMSG_FILE_SEQUENCE) ||
((transp.logMsg.entry.nsec / ANDROID_LOG_PMSG_FILE_SEQUENCE) >=
ANDROID_LOG_PMSG_FILE_MAX_SEQUENCE)) {
continue;
}
/* Determine if it has <dirbase>:<filebase> format for tag */
len = transp.logMsg.entry.len - sizeof(prio);
for (cp = msg + sizeof(prio); *cp && isprint(*cp) && !isspace(*cp) && --len; ++cp) {
if (*cp == ':') {
if (split) {
break;
}
split = cp;
}
}
if (*cp || !split) {
continue;
}
/* Filters */
if (prefix_len && strncmp(msg + sizeof(prio), prefix, prefix_len)) {
size_t offset;
/*
* Allow : to be a synonym for /
* Things we do dealing with const char * and do not alloc
*/
split = strchr(prefix, ':');
if (split) {
continue;
}
split = strchr(prefix, '/');
if (!split) {
continue;
}
offset = split - prefix;
if ((msg[offset + sizeof(prio)] != ':') || strncmp(msg + sizeof(prio), prefix, offset)) {
continue;
}
++offset;
if ((prefix_len > offset) &&
strncmp(&msg[offset + sizeof(prio)], split + 1, prefix_len - offset)) {
continue;
}
}
if ((prio != ANDROID_LOG_ANY) && (*msg < prio)) {
continue;
}
/* check if there is an existing entry */
list_for_each(node, &name_list) {
names = node_to_item(node, struct names, node);
if (!strcmp(names->name, msg + sizeof(prio)) && (names->id == transp.logMsg.entry.lid) &&
(names->prio == *msg)) {
break;
}
}
/* We do not have an existing entry, create and add one */
if (node == &name_list) {
static const char numbers[] = "0123456789";
unsigned long long nl;
len = strlen(msg + sizeof(prio)) + 1;
names = static_cast<struct names*>(calloc(1, sizeof(*names) + len));
if (!names) {
ret = -ENOMEM;
break;
}
strcpy(names->name, msg + sizeof(prio));
names->id = static_cast<log_id_t>(transp.logMsg.entry.lid);
names->prio = *msg;
list_init(&names->content);
/*
* Insert in reverse numeric _then_ alpha sorted order as
* representative of log rotation:
*
* log.10
* klog.10
* . . .
* log.2
* klog.2
* log.1
* klog.1
* log
* klog
*
* thus when we present the content, we are provided the oldest
* first, which when 'refreshed' could spill off the end of the
* pmsg FIFO but retaining the newest data for last with best
* chances to survive.
*/
nl = 0;
cp = strpbrk(names->name, numbers);
if (cp) {
nl = strtoull(cp, NULL, 10);
}
list_for_each_reverse(node, &name_list) {
struct names* a_name = node_to_item(node, struct names, node);
const char* r = a_name->name;
int compare = 0;
unsigned long long nr = 0;
cp = strpbrk(r, numbers);
if (cp) {
nr = strtoull(cp, NULL, 10);
}
if (nr != nl) {
compare = (nl > nr) ? 1 : -1;
}
if (compare == 0) {
compare = strcmp(names->name, r);
}
if (compare <= 0) {
break;
}
}
list_add_head(node, &names->node);
}
/* Remove any file fragments that match our sequence number */
list_for_each_safe(node, n, &names->content) {
content = node_to_item(node, struct content, node);
if (transp.logMsg.entry.nsec == content->entry.nsec) {
list_remove(&content->node);
free(content);
}
}
/* Add content */
content = static_cast<struct content*>(
calloc(1, sizeof(content->node) + hdr_size + transp.logMsg.entry.len));
if (!content) {
ret = -ENOMEM;
break;
}
memcpy(&content->entry, &transp.logMsg.entry, hdr_size + transp.logMsg.entry.len);
/* Insert in sequence number sorted order, to ease reconstruction */
list_for_each_reverse(node, &names->content) {
if ((node_to_item(node, struct content, node))->entry.nsec < transp.logMsg.entry.nsec) {
break;
}
}
list_add_head(node, &content->node);
}
pmsgClose(&logger_list, &transp);
/* Progress through all the collected files */
list_for_each_safe(node, n, &name_list) {
struct listnode *content_node, *m;
char* buf;
size_t sequence, tag_len;
names = node_to_item(node, struct names, node);
/* Construct content into a linear buffer */
buf = NULL;
len = 0;
sequence = 0;
tag_len = strlen(names->name) + sizeof(char); /* tag + nul */
list_for_each_safe(content_node, m, &names->content) {
ssize_t add_len;
content = node_to_item(content_node, struct content, node);
add_len = content->entry.len - tag_len - sizeof(prio);
if (add_len <= 0) {
list_remove(content_node);
free(content);
continue;
}
if (!buf) {
buf = static_cast<char*>(malloc(sizeof(char)));
if (!buf) {
ret = -ENOMEM;
list_remove(content_node);
free(content);
continue;
}
*buf = '\0';
}
/* Missing sequence numbers */
while (sequence < content->entry.nsec) {
/* plus space for enforced nul */
buf = static_cast<char*>(realloc_or_free(buf, len + sizeof(char) + sizeof(char)));
if (!buf) {
break;
}
buf[len] = '\f'; /* Mark missing content with a form feed */
buf[++len] = '\0';
sequence += ANDROID_LOG_PMSG_FILE_SEQUENCE;
}
if (!buf) {
ret = -ENOMEM;
list_remove(content_node);
free(content);
continue;
}
/* plus space for enforced nul */
buf = static_cast<char*>(realloc_or_free(buf, len + add_len + sizeof(char)));
if (!buf) {
ret = -ENOMEM;
list_remove(content_node);
free(content);
continue;
}
memcpy(buf + len, (char*)&content->entry + content->entry.hdr_size + tag_len + sizeof(prio),
add_len);
len += add_len;
buf[len] = '\0'; /* enforce trailing hidden nul */
sequence = content->entry.nsec + ANDROID_LOG_PMSG_FILE_SEQUENCE;
list_remove(content_node);
free(content);
}
if (buf) {
if (len) {
/* Buffer contains enforced trailing nul just beyond length */
ssize_t r;
*strchr(names->name, ':') = '/'; /* Convert back to filename */
r = (*fn)(names->id, names->prio, names->name, buf, len, arg);
if ((ret >= 0) && (r > 0)) {
if (ret == SSIZE_MAX) {
ret = r;
} else {
ret += r;
}
} else if (r < ret) {
ret = r;
}
}
free(buf);
}
list_remove(node);
free(names);
}
return (ret == SSIZE_MAX) ? -ENOENT : ret;
}
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