4 files changed, 80 insertions, 9 deletions

diff --git a/parse-events.c b/parse-events.c
index e9f122a..59596ae 100644
--- a/parse-events.c
+++ b/parse-events.c
@@ -4041,11 +4041,16 @@ static void print_args(struct print_arg *args)
 }
 
 static void parse_header_field(const char *field,
-                               int *offset, int *size)
+                               int *offset, int *size, int mandatory)
 {
+        unsigned long long save_input_buf_ptr;
+        unsigned long long save_input_buf_siz;
         char *token;
         int type;
 
+        save_input_buf_ptr = input_buf_ptr;
+        save_input_buf_siz = input_buf_siz;
+
         if (read_expected(EVENT_ITEM, "field") < 0)
                 return;
         if (read_expected(EVENT_OP, ":") < 0)
@@ -4056,8 +4061,20 @@ static void parse_header_field(const char *field,
                 goto fail;
         free_token(token);
 
-        if (read_expected(EVENT_ITEM, field) < 0)
-                return;
+        /*
+         * If this is not a mandatory field, then test it first.
+         */
+        if (mandatory) {
+                if (read_expected(EVENT_ITEM, field) < 0)
+                        return;
+        } else {
+                if (read_expect_type(EVENT_ITEM, &token) < 0)
+                        goto fail;
+                if (strcmp(token, field) != 0)
+                        goto discard;
+                free_token(token);
+        }
+
         if (read_expected(EVENT_OP, ";") < 0)
                 return;
         if (read_expected(EVENT_ITEM, "offset") < 0)
@@ -4106,6 +4123,14 @@ static void parse_header_field(const char *field,
         }
  fail:
         free_token(token);
+        return;
+
+ discard:
+        input_buf_ptr = save_input_buf_ptr;
+        input_buf_siz = save_input_buf_siz;
+        *offset = 0;
+        *size = 0;
+        free_token(token);
 }
 
 /**
@@ -4123,6 +4148,8 @@ static void parse_header_field(const char *field,
 int pevent_parse_header_page(struct pevent *pevent, char *buf, unsigned long size,
                              int long_size)
 {
+        int ignore;
+
         if (!size) {
                 /*
                  * Old kernels did not have header page info.
@@ -4137,11 +4164,13 @@ int pevent_parse_header_page(struct pevent *pevent, char *buf, unsigned long siz
         init_input_buf(buf, size);
 
         parse_header_field("timestamp", &pevent->header_page_ts_offset,
-                           &pevent->header_page_ts_size);
+                           &pevent->header_page_ts_size, 1);
         parse_header_field("commit", &pevent->header_page_size_offset,
-                           &pevent->header_page_size_size);
+                           &pevent->header_page_size_size, 1);
+        parse_header_field("overwrite", &pevent->header_page_overwrite,
+                           &ignore, 0);
         parse_header_field("data", &pevent->header_page_data_offset,
-                           &pevent->header_page_data_size);
+                           &pevent->header_page_data_size, 1);
 
         return 0;
 }
diff --git a/parse-events.h b/parse-events.h
index 03b382e..d79f4e0 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -38,6 +38,7 @@
 struct record {
         unsigned long long      ts;
         unsigned long long      offset;
+        long long               missed_events;  /* buffer dropped events before */
         int                     record_size;    /* size of binary record */
         int                     size;           /* size of data */
         void                    *data;
@@ -284,6 +285,7 @@ struct pevent {
         int header_page_size_size;
         int header_page_data_offset;
         int header_page_data_size;
+        int header_page_overwrite;
 
         int file_bigendian;
         int host_bigendian;
diff --git a/trace-input.c b/trace-input.c
index c919cd0..c70dc6b 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -39,6 +39,11 @@
 #include "trace-cmd-local.h"
 #include "list.h"
 
+#define MISSING_EVENTS (1 << 31)
+#define MISSING_STORED (1 << 30)
+
+#define COMMIT_MASK ((1 << 27) - 1)
+
 /* for debugging read instead of mmap */
 static int force_read = 0;
 
@@ -48,6 +53,7 @@ struct page {
         struct tracecmd_input   *handle;
         void                    *map;
         int                     ref_count;
+        long long               lost_events;
 };
 
 struct cpu_data {
@@ -679,6 +685,7 @@ static int update_page_info(struct tracecmd_input *handle, int cpu)
 {
         struct pevent *pevent = handle->pevent;
         void *ptr = handle->cpu_data[cpu].page->map;
+        unsigned int flags;
 
         /* FIXME: handle header page */
         if (pevent->header_page_ts_size != 8) {
@@ -690,16 +697,39 @@ static int update_page_info(struct tracecmd_input *handle, int cpu)
         ptr += 8;
         switch (pevent->header_page_size_size) {
         case 4:
-                handle->cpu_data[cpu].page_size = data2host4(pevent, ptr);
+                flags = data2host4(pevent, ptr);
+                ptr += 4;
                 break;
         case 8:
-                handle->cpu_data[cpu].page_size = data2host8(pevent, ptr);
+                flags = (unsigned int)data2host8(pevent, ptr);
+                ptr += 8;
                 break;
         default:
                 warning("bad long size");
                 return -1;
         }
 
+        handle->cpu_data[cpu].page_size = flags & COMMIT_MASK;
+
+        if (flags & MISSING_EVENTS) {
+                breakpoint();
+                if (flags & MISSING_STORED) {
+                        ptr += handle->cpu_data[cpu].page_size;
+                        switch (pevent->header_page_size_size) {
+                        case 4:
+                                handle->cpu_data[cpu].page->lost_events =
+                                        data2host4(pevent, ptr);
+                                break;
+                        case 8:
+                                handle->cpu_data[cpu].page->lost_events =
+                                        data2host8(pevent, ptr);
+                                break;
+                        }
+                } else
+                        handle->cpu_data[cpu].page->lost_events = -1;
+        } else
+                handle->cpu_data[cpu].page->lost_events = 0;
+
         handle->cpu_data[cpu].index = 0;
 
         return 0;
@@ -1435,6 +1465,7 @@ tracecmd_peek_data(struct tracecmd_input *handle, int cpu)
         void *ptr;
         unsigned long long extend;
         unsigned int type_len;
+        long long missed_events = 0;
         int length;
 
         if (index < 0)
@@ -1464,8 +1495,10 @@ tracecmd_peek_data(struct tracecmd_input *handle, int cpu)
 
         ptr = page->map + index;
 
-        if (!index)
+        if (!index) {
+                missed_events = page->lost_events;
                 ptr = handle->cpu_data[cpu].page->map + pevent->header_page_data_offset;
+        }
 
 read_again:
         index = calc_index(handle, ptr, cpu);
@@ -1520,6 +1553,7 @@ read_again:
         record->cpu = cpu;
         record->data = ptr;
         record->offset = handle->cpu_data[cpu].offset + index;
+        record->missed_events = missed_events;
 
         ptr += length;
 
diff --git a/trace-read.c b/trace-read.c
index 80173f9..bbe34ba 100644
--- a/trace-read.c
+++ b/trace-read.c
@@ -462,6 +462,12 @@ static void show_data(struct tracecmd_input *handle,
         test_save(record, cpu);
 
         trace_seq_init(&s);
+        if (record->missed_events > 0)
+                trace_seq_printf(&s, "CPU:%d [%lld EVENTS DROPPED]\n",
+                                 record->cpu, record->missed_events);
+        else if (record->missed_events < 0)
+                trace_seq_printf(&s, "CPU:%d [EVENTS DROPPED]\n",
+                                 record->cpu);
         pevent_print_event(pevent, &s, record);
         trace_seq_do_printf(&s);