trace-cmd/restore: Allow override where debugfs/tracing and kallsyms come from

Add to trace-cmd restore:

  -t dir: where dir is the directory to search instead of looking at
          debugfs/tracing

  -k file: where to read kallsyms from, instead of reading
           /proc/kallsyms

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

4 files changed, 57 insertions, 10 deletions

diff --git a/Documentation/trace-cmd-restore.1.txt b/Documentation/trace-cmd-restore.1.txt
index 6fd6ba4..290b0ac 100644
--- a/Documentation/trace-cmd-restore.1.txt
+++ b/Documentation/trace-cmd-restore.1.txt
@@ -42,6 +42,21 @@ OPTIONS
     'trace-partial.dat'. This is because the file is not a full version
     of something that trace-cmd-report(1) could use.
 
+*-t* tracing_dir::
+    Used with *-c*, it overrides the location to read the events from.
+    By default, tracing information is read from the debugfs/tracing
+    directory. *-t* will use that location instead. This can be useful
+    if the trace.dat file to create is from another machine.
+    Just tar -cvf events.tar debugfs/tracing and copy and untar that
+    file locally, and use that directory instead.
+
+*-k* kallsyms::
+    Used with *-c*, it overrides where to read the kallsyms file from.
+    By default, /proc/kallsyms is used. *-k* will override the file to
+    read the kallsyms from. This can be useful if the trace.dat file
+    to create is from another machine. Just copy the /proc/kallsyms
+    file locally, and use *-k* to point to that file.
+
 *-o* output'::
     By default, trace-cmd restore will create a 'trace.dat' file
     (or 'trace-partial.dat' if *-c* is specified). You can
diff --git a/trace-cmd.h b/trace-cmd.h
index ec59e98..708d743 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -174,6 +174,9 @@ tracecmd_create_file_glob(const char *output_file,
                           struct tracecmd_event_list *event_globs);
 struct tracecmd_output *tracecmd_create_init_fd(int fd);
 struct tracecmd_output *tracecmd_create_init_file(const char *output_file);
+struct tracecmd_output *tracecmd_create_init_file_override(const char *output_file,
+                                                           const char *tracing_dir,
+                                                           const char *kallsyms);
 void tracecmd_output_close(struct tracecmd_output *handle);
 struct tracecmd_output *tracecmd_copy(struct tracecmd_input *ihandle,
                                       const char *file);
diff --git a/trace-output.c b/trace-output.c
index 8837aa0..26b0197 100644
--- a/trace-output.c
+++ b/trace-output.c
@@ -599,13 +599,17 @@ static int read_event_files(struct tracecmd_output *handle,
         return ret;
 }
 
-static int read_proc_kallsyms(struct tracecmd_output *handle)
+static int read_proc_kallsyms(struct tracecmd_output *handle,
+                              const char *kallsyms)
 {
         unsigned int size, check_size, endian4;
         const char *path = "/proc/kallsyms";
         struct stat st;
         int ret;
 
+        if (kallsyms)
+                path = kallsyms;
+
         ret = stat(path, &st);
         if (ret < 0) {
                 /* not found */
@@ -665,6 +669,8 @@ static int read_ftrace_printk(struct tracecmd_output *handle)
 
 static struct tracecmd_output *
 create_file_fd(int fd, struct tracecmd_input *ihandle,
+               const char *tracing_dir,
+               const char *kallsyms,
                struct tracecmd_event_list *list)
 {
         struct tracecmd_output *handle;
@@ -684,6 +690,11 @@ create_file_fd(int fd, struct tracecmd_input *ihandle,
         memset(handle, 0, sizeof(*handle));
 
         handle->fd = fd;
+        if (tracing_dir) {
+                handle->tracing_dir = strdup(tracing_dir);
+                if (!handle->tracing_dir)
+                        goto out_free;
+        }
 
         buf[0] = 23;
         buf[1] = 8;
@@ -736,7 +747,7 @@ create_file_fd(int fd, struct tracecmd_input *ihandle,
                 goto out_free;
         if (read_event_files(handle, list))
                 goto out_free;
-        if (read_proc_kallsyms(handle))
+        if (read_proc_kallsyms(handle, kallsyms))
                 goto out_free;
         if (read_ftrace_printk(handle))
                 goto out_free;
@@ -775,6 +786,8 @@ create_file_fd(int fd, struct tracecmd_input *ihandle,
 
 static struct tracecmd_output *create_file(const char *output_file,
                                            struct tracecmd_input *ihandle,
+                                           const char *tracing_dir,
+                                           const char *kallsyms,
                                            struct tracecmd_event_list *list)
 {
         struct tracecmd_output *handle;
@@ -784,7 +797,7 @@ static struct tracecmd_output *create_file(const char *output_file,
         if (fd < 0)
                 return NULL;
 
-        handle = create_file_fd(fd, ihandle, list);
+        handle = create_file_fd(fd, ihandle, tracing_dir, kallsyms, list);
         if (!handle) {
                 close(fd);
                 unlink(output_file);
@@ -870,7 +883,7 @@ struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, in
         struct tracecmd_output *handle;
         char *path;
 
-        handle = create_file(output_file, NULL, &all_event_list);
+        handle = create_file(output_file, NULL, NULL, NULL, &all_event_list);
         if (!handle)
                 return NULL;
 
@@ -1050,7 +1063,7 @@ tracecmd_create_file_glob(const char *output_file,
 {
         struct tracecmd_output *handle;
 
-        handle = create_file(output_file, NULL, list);
+        handle = create_file(output_file, NULL, NULL, NULL, list);
         if (!handle)
                 return NULL;
 
@@ -1069,12 +1082,19 @@ struct tracecmd_output *tracecmd_create_file(const char *output_file,
 
 struct tracecmd_output *tracecmd_create_init_fd(int fd)
 {
-        return create_file_fd(fd, NULL, &all_event_list);
+        return create_file_fd(fd, NULL, NULL, NULL, &all_event_list);
 }
 
 struct tracecmd_output *tracecmd_create_init_file(const char *output_file)
 {
-        return create_file(output_file, NULL, &all_event_list);
+        return create_file(output_file, NULL, NULL, NULL, &all_event_list);
+}
+
+struct tracecmd_output *tracecmd_create_init_file_override(const char *output_file,
+                                                           const char *tracing_dir,
+                                                           const char *kallsyms)
+{
+        return create_file(output_file, NULL, tracing_dir, kallsyms, &all_event_list);
 }
 
 /**
@@ -1091,7 +1111,7 @@ struct tracecmd_output *tracecmd_copy(struct tracecmd_input *ihandle,
 {
         struct tracecmd_output *handle;
 
-        handle = create_file(file, ihandle, &all_event_list);
+        handle = create_file(file, ihandle, NULL, NULL, &all_event_list);
         if (!handle)
                 return NULL;
 
diff --git a/trace-restore.c b/trace-restore.c
index cf8c14f..d255546 100644
--- a/trace-restore.c
+++ b/trace-restore.c
@@ -45,6 +45,8 @@ void trace_restore (int argc, char **argv)
         const char *output_file = "trace.dat";
         const char *output = NULL;
         const char *input = NULL;
+        const char *tracing_dir = NULL;
+        const char *kallsyms = NULL;
         struct stat st1;
         struct stat st2;
         int first_arg;
@@ -58,7 +60,7 @@ void trace_restore (int argc, char **argv)
         if (strcmp(argv[1], "restore") != 0)
                 usage(argv);
 
-        while ((c = getopt(argc-1, argv+1, "+hco:i:")) >= 0) {
+        while ((c = getopt(argc-1, argv+1, "+hco:i:t:k:")) >= 0) {
                 switch (c) {
                 case 'h':
                         usage(argv);
@@ -71,6 +73,12 @@ void trace_restore (int argc, char **argv)
                         output_file = "trace-partial.dat";
                         break;
 
+                case 't':
+                        tracing_dir = optarg;
+                        break;
+                case 'k':
+                        kallsyms = optarg;
+                        break;
                 case 'o':
                         if (output)
                                 die("only one output file allowed");
@@ -99,7 +107,8 @@ void trace_restore (int argc, char **argv)
                         usage(argv);
                 }
 
-                handle = tracecmd_create_init_file(output);
+                handle = tracecmd_create_init_file_override(output, tracing_dir,
+                                                            kallsyms);
                 if (!handle)
                         die("Unabled to create output file %s", output);
                 tracecmd_output_close(handle);