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
diff --git a/include/private/android_logger.h b/include/private/android_logger.h
index a637ca5..c3ea1ed 100644
--- a/include/private/android_logger.h
+++ b/include/private/android_logger.h
@@ -111,6 +111,20 @@
const char *filename,
const char *buf, size_t len);
+#define LOG_ID_ANY ((log_id_t)-1)
+#define ANDROID_LOG_ANY ANDROID_LOG_UNKNOWN
+
+/* first 5 arguments match __android_log_msg_file_write, a cast is safe */
+typedef ssize_t (*__android_log_pmsg_file_read_fn)(
+ log_id_t logId,
+ char prio,
+ const char *filename,
+ const char *buf, size_t len, void *arg);
+
+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);
+
#if defined(__cplusplus)
}
#endif
diff --git a/liblog/pmsg_reader.c b/liblog/pmsg_reader.c
index de435f7..5695e8a 100644
--- a/liblog/pmsg_reader.c
+++ b/liblog/pmsg_reader.c
@@ -14,9 +14,11 @@
* limitations under the License.
*/
+#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
+#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
@@ -253,3 +255,333 @@
}
transp->context.fd = 0;
}
+
+LIBLOG_ABI_PRIVATE 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;
+ union {
+ struct logger_entry_v4 entry;
+ struct logger_entry_v4 entry_v4;
+ struct logger_entry_v3 entry_v3;
+ struct logger_entry_v2 entry_v2;
+ struct logger_entry entry_v1;
+ };
+ } *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) {
+ char *cp;
+ size_t hdr_size = transp.logMsg.entry.hdr_size ?
+ transp.logMsg.entry.hdr_size : sizeof(transp.logMsg.entry_v1);
+ char *msg = (char *)&transp.logMsg + hdr_size;
+ char *split = NULL;
+
+ /* 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 = calloc(1, sizeof(*names) + len);
+ if (!names) {
+ ret = -ENOMEM;
+ break;
+ }
+ strcpy(names->name, msg + sizeof(prio));
+ names->id = 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 = 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 = 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 = realloc(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 = realloc(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;
+}
diff --git a/liblog/tests/liblog_test.cpp b/liblog/tests/liblog_test.cpp
index f315791..941b9b9 100644
--- a/liblog/tests/liblog_test.cpp
+++ b/liblog/tests/liblog_test.cpp
@@ -2531,5 +2531,48 @@
EXPECT_LT(0, __android_log_pmsg_file_write(
LOG_ID_CRASH, ANDROID_LOG_VERBOSE,
__pmsg_file, max_payload_buf, sizeof(max_payload_buf)));
- fprintf(stderr, "Reboot, ensure file %s matches\n", __pmsg_file);
+ fprintf(stderr, "Reboot, ensure file %s matches\n"
+ "with liblog.__android_log_msg_file_read test\n",
+ __pmsg_file);
+}
+
+ssize_t __pmsg_fn(log_id_t logId, char prio, const char *filename,
+ const char *buf, size_t len, void *arg) {
+ EXPECT_TRUE(NULL == arg);
+ EXPECT_EQ(LOG_ID_CRASH, logId);
+ EXPECT_EQ(ANDROID_LOG_VERBOSE, prio);
+ EXPECT_FALSE(NULL == strstr(__pmsg_file, filename));
+ EXPECT_EQ(len, sizeof(max_payload_buf));
+ EXPECT_EQ(0, strcmp(max_payload_buf, buf));
+
+ ++signaled;
+ if ((len != sizeof(max_payload_buf)) ||
+ strcmp(max_payload_buf, buf)) {
+ fprintf(stderr, "comparison fails on content \"%s\"\n", buf);
+ }
+ return !arg ||
+ (LOG_ID_CRASH != logId) ||
+ (ANDROID_LOG_VERBOSE != prio) ||
+ !strstr(__pmsg_file, filename) ||
+ (len != sizeof(max_payload_buf)) ||
+ !!strcmp(max_payload_buf, buf) ? -ENOEXEC : 1;
+}
+
+TEST(liblog, __android_log_pmsg_file_read) {
+ signaled = 0;
+
+ ssize_t ret = __android_log_pmsg_file_read(
+ LOG_ID_CRASH, ANDROID_LOG_VERBOSE,
+ __pmsg_file, __pmsg_fn, NULL);
+
+ if (ret == -ENOENT) {
+ fprintf(stderr,
+ "No pre-boot results of liblog.__android_log_mesg_file_write to "
+ "compare with,\n"
+ "false positive test result.\n");
+ return;
+ }
+
+ EXPECT_LT(0, ret);
+ EXPECT_EQ(1U, signaled);
}