trace-cmd: Handle empty CPUs without crashing

The get_page() needs to return -1 on reading a CPU that has no
data.

Also added checks of get_page() return status that was missing
from some callers.

Have tracecmd_set_cpu_to_timestamp() also return -1 when reading an
empty CPU.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 13 insertions, 3 deletions

diff --git a/trace-input.c b/trace-input.c
index 0c7f9ad..69c2ce7 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -678,6 +678,10 @@ static int get_page(struct tracecmd_input *handle, int cpu,
             handle->cpu_data[cpu].page)
                 return 1;
 
+        /* Do not map no data for CPU */
+        if (!handle->cpu_data[cpu].size)
+                return -1;
+
         if (offset & (handle->page_size - 1)) {
                 errno = -EINVAL;
                 die("bad page offset %llx", offset);
@@ -941,7 +945,7 @@ int tracecmd_refresh_record(struct tracecmd_input *handle,
         page_offset = record->offset & ~(handle->page_size - 1);
         index = record->offset & (handle->page_size - 1);
 
-        ret = get_page(handle, record->cpu, page_offset) < 0;
+        ret =get_page(handle, record->cpu, page_offset);
         if (ret < 0)
                 return -1;
 
@@ -976,7 +980,9 @@ int tracecmd_refresh_record(struct tracecmd_input *handle,
 struct record *
 tracecmd_read_cpu_first(struct tracecmd_input *handle, int cpu)
 {
-        get_page(handle, cpu, handle->cpu_data[cpu].file_offset);
+        if (get_page(handle, cpu, handle->cpu_data[cpu].file_offset) < 0)
+                return NULL;
+
         handle->cpu_data[cpu].index = 0;
         if (handle->cpu_data[cpu].next) {
                 free_record(handle->cpu_data[cpu].next);
@@ -1009,7 +1015,8 @@ tracecmd_read_cpu_last(struct tracecmd_input *handle, int cpu)
         else
                 offset -= handle->page_size;
 
-        get_page(handle, cpu, offset);
+        if (get_page(handle, cpu, offset) < 0)
+                return NULL;
 
         do {
                 free_record(record);
@@ -1048,6 +1055,9 @@ tracecmd_set_cpu_to_timestamp(struct tracecmd_input *handle, int cpu,
                 return -1;
         }
 
+        if (!cpu_data->size)
+                return -1;
+
         if (!cpu_data->page) {
                 if (init_cpu(handle, cpu))
                     return -1;