liblog: add __android_log_pmsg_file_read
- This is considered an Android Private function, not exported for general use. - goal is to retreive a file's content from a series of log messages from pmsg, to be retrieved after a reboot for transfer to a persistent location. - files are presented in reverse sorted order, first based on _any_ numerical content, then by alphanumeric order. - Add a gTest for this function, relies on gTest for liblog.__android_log_pmsg_file_write from prior to reboot. Bug: 27176738 Change-Id: If37ef423009bd28b598b233af3bccef3429bdc22
This commit is contained in:
Mark Salyzyn
Dan Willemsen
parent
d4b061bde2
commit
864e8e80e4
3 changed files with 390 additions and 1 deletions
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@ -111,6 +111,20 @@ ssize_t __android_log_pmsg_file_write(
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const char *filename,
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const char *buf, size_t len);
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#define LOG_ID_ANY ((log_id_t)-1)
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#define ANDROID_LOG_ANY ANDROID_LOG_UNKNOWN
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/* first 5 arguments match __android_log_msg_file_write, a cast is safe */
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typedef ssize_t (*__android_log_pmsg_file_read_fn)(
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log_id_t logId,
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char prio,
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const char *filename,
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const char *buf, size_t len, void *arg);
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ssize_t __android_log_pmsg_file_read(
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log_id_t logId, char prio, const char *prefix,
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__android_log_pmsg_file_read_fn fn, void *arg);
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#if defined(__cplusplus)
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}
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#endif
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@ -14,9 +14,11 @@
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* limitations under the License.
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*/
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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@ -253,3 +255,333 @@ static void pmsgClose(struct android_log_logger_list *logger_list __unused,
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}
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transp->context.fd = 0;
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}
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LIBLOG_ABI_PRIVATE ssize_t __android_log_pmsg_file_read(
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log_id_t logId,
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char prio,
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const char *prefix,
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__android_log_pmsg_file_read_fn fn, void *arg) {
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ssize_t ret;
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struct android_log_logger_list logger_list;
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struct android_log_transport_context transp;
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struct content {
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struct listnode node;
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union {
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struct logger_entry_v4 entry;
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struct logger_entry_v4 entry_v4;
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struct logger_entry_v3 entry_v3;
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struct logger_entry_v2 entry_v2;
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struct logger_entry entry_v1;
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};
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} *content;
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struct names {
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struct listnode node;
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struct listnode content;
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log_id_t id;
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char prio;
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char name[];
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} *names;
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struct listnode name_list;
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struct listnode *node, *n;
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size_t len, prefix_len;
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if (!fn) {
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return -EINVAL;
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}
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/* Add just enough clues in logger_list and transp to make API function */
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memset(&logger_list, 0, sizeof(logger_list));
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memset(&transp, 0, sizeof(transp));
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logger_list.mode = ANDROID_LOG_PSTORE |
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ANDROID_LOG_NONBLOCK |
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ANDROID_LOG_RDONLY;
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transp.logMask = (unsigned)-1;
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if (logId != LOG_ID_ANY) {
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transp.logMask = (1 << logId);
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}
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transp.logMask &= ~((1 << LOG_ID_KERNEL) |
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(1 << LOG_ID_EVENTS) |
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(1 << LOG_ID_SECURITY));
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if (!transp.logMask) {
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return -EINVAL;
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}
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/* Initialize name list */
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list_init(&name_list);
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ret = SSIZE_MAX;
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/* Validate incoming prefix, shift until it contains only 0 or 1 : or / */
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prefix_len = 0;
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if (prefix) {
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const char *prev = NULL, *last = NULL, *cp = prefix;
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while ((cp = strpbrk(cp, "/:"))) {
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prev = last;
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last = cp;
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cp = cp + 1;
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}
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if (prev) {
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prefix = prev + 1;
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}
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prefix_len = strlen(prefix);
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}
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/* Read the file content */
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while (pmsgRead(&logger_list, &transp, &transp.logMsg) > 0) {
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char *cp;
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size_t hdr_size = transp.logMsg.entry.hdr_size ?
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transp.logMsg.entry.hdr_size : sizeof(transp.logMsg.entry_v1);
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char *msg = (char *)&transp.logMsg + hdr_size;
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char *split = NULL;
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/* Check for invalid sequence number */
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if ((transp.logMsg.entry.nsec % ANDROID_LOG_PMSG_FILE_SEQUENCE) ||
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((transp.logMsg.entry.nsec / ANDROID_LOG_PMSG_FILE_SEQUENCE) >=
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ANDROID_LOG_PMSG_FILE_MAX_SEQUENCE)) {
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continue;
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}
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/* Determine if it has <dirbase>:<filebase> format for tag */
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len = transp.logMsg.entry.len - sizeof(prio);
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for (cp = msg + sizeof(prio);
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*cp && isprint(*cp) && !isspace(*cp) && --len;
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++cp) {
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if (*cp == ':') {
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if (split) {
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break;
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}
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split = cp;
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}
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}
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if (*cp || !split) {
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continue;
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}
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/* Filters */
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if (prefix_len && strncmp(msg + sizeof(prio), prefix, prefix_len)) {
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size_t offset;
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/*
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* Allow : to be a synonym for /
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* Things we do dealing with const char * and do not alloc
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*/
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split = strchr(prefix, ':');
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if (split) {
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continue;
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}
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split = strchr(prefix, '/');
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if (!split) {
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continue;
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}
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offset = split - prefix;
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if ((msg[offset + sizeof(prio)] != ':') ||
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strncmp(msg + sizeof(prio), prefix, offset)) {
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continue;
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}
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++offset;
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if ((prefix_len > offset) &&
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strncmp(&msg[offset + sizeof(prio)], split + 1, prefix_len - offset)) {
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continue;
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}
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}
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if ((prio != ANDROID_LOG_ANY) && (*msg < prio)) {
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continue;
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}
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/* check if there is an existing entry */
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list_for_each(node, &name_list) {
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names = node_to_item(node, struct names, node);
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if (!strcmp(names->name, msg + sizeof(prio)) &&
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(names->id == transp.logMsg.entry.lid) &&
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(names->prio == *msg)) {
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break;
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}
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}
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/* We do not have an existing entry, create and add one */
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if (node == &name_list) {
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static const char numbers[] = "0123456789";
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unsigned long long nl;
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len = strlen(msg + sizeof(prio)) + 1;
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names = calloc(1, sizeof(*names) + len);
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if (!names) {
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ret = -ENOMEM;
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break;
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}
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strcpy(names->name, msg + sizeof(prio));
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names->id = transp.logMsg.entry.lid;
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names->prio = *msg;
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list_init(&names->content);
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/*
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* Insert in reverse numeric _then_ alpha sorted order as
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* representative of log rotation:
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*
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* log.10
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* klog.10
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* . . .
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* log.2
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* klog.2
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* log.1
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* klog.1
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* log
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* klog
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*
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* thus when we present the content, we are provided the oldest
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* first, which when 'refreshed' could spill off the end of the
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* pmsg FIFO but retaining the newest data for last with best
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* chances to survive.
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*/
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nl = 0;
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cp = strpbrk(names->name, numbers);
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if (cp) {
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nl = strtoull(cp, NULL, 10);
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}
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list_for_each_reverse(node, &name_list) {
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struct names *a_name = node_to_item(node, struct names, node);
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const char *r = a_name->name;
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int compare = 0;
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unsigned long long nr = 0;
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cp = strpbrk(r, numbers);
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if (cp) {
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nr = strtoull(cp, NULL, 10);
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}
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if (nr != nl) {
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compare = (nl > nr) ? 1 : -1;
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}
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if (compare == 0) {
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compare = strcmp(names->name, r);
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}
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if (compare <= 0) {
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break;
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}
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}
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list_add_head(node, &names->node);
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}
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/* Remove any file fragments that match our sequence number */
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list_for_each_safe(node, n, &names->content) {
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content = node_to_item(node, struct content, node);
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if (transp.logMsg.entry.nsec == content->entry.nsec) {
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list_remove(&content->node);
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free(content);
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}
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}
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/* Add content */
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content = calloc(1, sizeof(content->node) +
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hdr_size + transp.logMsg.entry.len);
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if (!content) {
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ret = -ENOMEM;
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break;
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}
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memcpy(&content->entry, &transp.logMsg.entry,
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hdr_size + transp.logMsg.entry.len);
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/* Insert in sequence number sorted order, to ease reconstruction */
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list_for_each_reverse(node, &names->content) {
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if ((node_to_item(node, struct content, node))->entry.nsec <
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transp.logMsg.entry.nsec) {
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break;
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}
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}
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list_add_head(node, &content->node);
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}
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pmsgClose(&logger_list, &transp);
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/* Progress through all the collected files */
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list_for_each_safe(node, n, &name_list) {
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struct listnode *content_node, *m;
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char *buf;
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size_t sequence, tag_len;
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names = node_to_item(node, struct names, node);
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/* Construct content into a linear buffer */
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buf = NULL;
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len = 0;
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sequence = 0;
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tag_len = strlen(names->name) + sizeof(char); /* tag + nul */
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list_for_each_safe(content_node, m, &names->content) {
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ssize_t add_len;
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content = node_to_item(content_node, struct content, node);
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add_len = content->entry.len - tag_len - sizeof(prio);
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if (add_len <= 0) {
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list_remove(content_node);
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free(content);
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continue;
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}
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if (!buf) {
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buf = malloc(sizeof(char));
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if (!buf) {
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ret = -ENOMEM;
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list_remove(content_node);
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free(content);
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continue;
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}
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*buf = '\0';
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}
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/* Missing sequence numbers */
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while (sequence < content->entry.nsec) {
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/* plus space for enforced nul */
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buf = realloc(buf, len + sizeof(char) + sizeof(char));
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if (!buf) {
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break;
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}
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buf[len] = '\f'; /* Mark missing content with a form feed */
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buf[++len] = '\0';
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sequence += ANDROID_LOG_PMSG_FILE_SEQUENCE;
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}
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if (!buf) {
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ret = -ENOMEM;
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list_remove(content_node);
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free(content);
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continue;
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}
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/* plus space for enforced nul */
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buf = realloc(buf, len + add_len + sizeof(char));
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if (!buf) {
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ret = -ENOMEM;
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list_remove(content_node);
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free(content);
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continue;
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}
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memcpy(buf + len,
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(char *)&content->entry + content->entry.hdr_size +
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tag_len + sizeof(prio),
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add_len);
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len += add_len;
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buf[len] = '\0'; /* enforce trailing hidden nul */
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sequence = content->entry.nsec + ANDROID_LOG_PMSG_FILE_SEQUENCE;
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list_remove(content_node);
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free(content);
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}
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if (buf) {
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if (len) {
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/* Buffer contains enforced trailing nul just beyond length */
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ssize_t r;
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*strchr(names->name, ':') = '/'; /* Convert back to filename */
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r = (*fn)(names->id, names->prio, names->name, buf, len, arg);
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if ((ret >= 0) && (r > 0)) {
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if (ret == SSIZE_MAX) {
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ret = r;
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} else {
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ret += r;
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}
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} else if (r < ret) {
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ret = r;
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}
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}
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free(buf);
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}
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list_remove(node);
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free(names);
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}
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return (ret == SSIZE_MAX) ? -ENOENT : ret;
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}
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@ -2531,5 +2531,48 @@ TEST(liblog, __android_log_pmsg_file_write) {
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EXPECT_LT(0, __android_log_pmsg_file_write(
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LOG_ID_CRASH, ANDROID_LOG_VERBOSE,
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__pmsg_file, max_payload_buf, sizeof(max_payload_buf)));
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fprintf(stderr, "Reboot, ensure file %s matches\n", __pmsg_file);
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fprintf(stderr, "Reboot, ensure file %s matches\n"
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"with liblog.__android_log_msg_file_read test\n",
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__pmsg_file);
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}
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ssize_t __pmsg_fn(log_id_t logId, char prio, const char *filename,
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const char *buf, size_t len, void *arg) {
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EXPECT_TRUE(NULL == arg);
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EXPECT_EQ(LOG_ID_CRASH, logId);
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EXPECT_EQ(ANDROID_LOG_VERBOSE, prio);
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EXPECT_FALSE(NULL == strstr(__pmsg_file, filename));
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EXPECT_EQ(len, sizeof(max_payload_buf));
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EXPECT_EQ(0, strcmp(max_payload_buf, buf));
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++signaled;
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if ((len != sizeof(max_payload_buf)) ||
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strcmp(max_payload_buf, buf)) {
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fprintf(stderr, "comparison fails on content \"%s\"\n", buf);
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}
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return !arg ||
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(LOG_ID_CRASH != logId) ||
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(ANDROID_LOG_VERBOSE != prio) ||
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!strstr(__pmsg_file, filename) ||
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(len != sizeof(max_payload_buf)) ||
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!!strcmp(max_payload_buf, buf) ? -ENOEXEC : 1;
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}
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TEST(liblog, __android_log_pmsg_file_read) {
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signaled = 0;
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ssize_t ret = __android_log_pmsg_file_read(
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LOG_ID_CRASH, ANDROID_LOG_VERBOSE,
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__pmsg_file, __pmsg_fn, NULL);
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if (ret == -ENOENT) {
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fprintf(stderr,
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"No pre-boot results of liblog.__android_log_mesg_file_write to "
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"compare with,\n"
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"false positive test result.\n");
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return;
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}
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EXPECT_LT(0, ret);
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EXPECT_EQ(1U, signaled);
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}
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