| Message ID | 20210301143856.948525416@goodmis.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | trace-cmd: Fixes for trace-cmd restore | expand |
Hi Steven, On Mon, Mar 1, 2021 at 4:38 PM Steven Rostedt <rostedt@goodmis.org> wrote: > > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org> > > The trace-cmd restore operation can create a partial header to read the > trace event formats and kallsyms and other data into a stand alone header > before it has access to the cpu data. Then it will also read this header to > put together a broken trace, and it reads the header that does not have the > cpu data attached to it. > > In order to handle this case, it needs a way to read the headers but stop > short of reading the CPU information. That requires breaking up > tracecmd_read_headers() with just stopping short of adding the cpu data. While looking at these changes, I think it could be more flexible instead of introducing a new API, to enhance the existing tracecmd_read_headers(). We can add an additional (optional) parameter to point out what headers to be read, i.e. the desired new state of reading the file. Something like that: int tracecmd_read_headers(struct tracecmd_input *handle, int state); It will read the file from its current file_state to the desired state. The API could be called multiple times, to progress the reading of the file, header by header if needed, or a bunch of headers. > > A new API is added called tracecmd_read_pre_headers() that does exactly that. > > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> > --- > .../include/private/trace-cmd-private.h | 1 + > lib/trace-cmd/trace-input.c | 25 ++++++++++++++++--- > tracecmd/trace-restore.c | 2 +- > 3 files changed, 24 insertions(+), 4 deletions(-) > > diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h > index fc968cc9efe1..c7ef3af7c8f7 100644 > --- a/lib/trace-cmd/include/private/trace-cmd-private.h > +++ b/lib/trace-cmd/include/private/trace-cmd-private.h > @@ -153,6 +153,7 @@ typedef void (*tracecmd_handle_init_func)(struct tracecmd_input *handle, > struct tracecmd_input *tracecmd_alloc(const char *file, int flags); > struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags); > void tracecmd_ref(struct tracecmd_input *handle); > +int tracecmd_read_pre_headers(struct tracecmd_input *handle); > int tracecmd_read_headers(struct tracecmd_input *handle); > int tracecmd_get_parsing_failures(struct tracecmd_input *handle); > int tracecmd_long_size(struct tracecmd_input *handle); > diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c > index 9ef7b9f16951..9e1a44540201 100644 > --- a/lib/trace-cmd/trace-input.c > +++ b/lib/trace-cmd/trace-input.c > @@ -772,14 +772,17 @@ static int read_cpus(struct tracecmd_input *handle) > } > > /** > - * tracecmd_read_headers - read the header information from trace.dat > + * tracecmd_read_pre_headers - read the header information from trace.dat > * @handle: input handle for the trace.dat file > * > * This reads the trace.dat file for various information. Like the > * format of the ring buffer, event formats, ftrace formats, kallsyms > - * and printk. > + * and printk, but stops before reading cpu and options. > + * > + * This is needed by the restore operation where the header does not > + * have the CPU information yet. > */ > -int tracecmd_read_headers(struct tracecmd_input *handle) > +int tracecmd_read_pre_headers(struct tracecmd_input *handle) > { > int ret; > > @@ -815,6 +818,22 @@ int tracecmd_read_headers(struct tracecmd_input *handle) > return -1; > handle->file_state = TRACECMD_FILE_CMD_LINES; > > + return 0; > +} > + > +/** > + * tracecmd_read_headers - read the header information from trace.dat > + * @handle: input handle for the trace.dat file > + * > + * This reads the trace.dat file for various information. Like the > + * format of the ring buffer, event formats, ftrace formats, kallsyms > + * and printk. > + */ > +int tracecmd_read_headers(struct tracecmd_input *handle) > +{ > + if (tracecmd_read_pre_headers(handle)) > + return -1; > + > if (read_cpus(handle) < 0) > return -1; > handle->file_state = TRACECMD_FILE_CPU_COUNT; > diff --git a/tracecmd/trace-restore.c b/tracecmd/trace-restore.c > index 13f803053582..bf6940991178 100644 > --- a/tracecmd/trace-restore.c > +++ b/tracecmd/trace-restore.c > @@ -122,7 +122,7 @@ void trace_restore (int argc, char **argv) > if (!ihandle) > die("error reading file %s", input); > /* make sure headers are ok */ > - if (tracecmd_read_headers(ihandle) < 0) > + if (tracecmd_read_pre_headers(ihandle) < 0) > die("error reading file %s headers", input); > > handle = tracecmd_copy(ihandle, output); > -- > 2.30.0 > > -- Tzvetomir (Ceco) Stoyanov VMware Open Source Technology Center
On Tue, 2 Mar 2021 06:49:18 +0200 Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote: > While looking at these changes, I think it could be more flexible instead of > introducing a new API, to enhance the existing tracecmd_read_headers(). > We can add an additional (optional) parameter to point out what headers > to be read, i.e. the desired new state of reading the file. Something like that: > int tracecmd_read_headers(struct tracecmd_input *handle, int state); > It will read the file from its current file_state to the desired state. > The API could be called multiple times, to progress the reading of the > file, header by header if needed, or a bunch of headers. > I actually like this idea. The only downside of it, is that we need to make the states part of the API (export them). -- Steve
diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h index fc968cc9efe1..c7ef3af7c8f7 100644 --- a/lib/trace-cmd/include/private/trace-cmd-private.h +++ b/lib/trace-cmd/include/private/trace-cmd-private.h @@ -153,6 +153,7 @@ typedef void (*tracecmd_handle_init_func)(struct tracecmd_input *handle, struct tracecmd_input *tracecmd_alloc(const char *file, int flags); struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags); void tracecmd_ref(struct tracecmd_input *handle); +int tracecmd_read_pre_headers(struct tracecmd_input *handle); int tracecmd_read_headers(struct tracecmd_input *handle); int tracecmd_get_parsing_failures(struct tracecmd_input *handle); int tracecmd_long_size(struct tracecmd_input *handle); diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c index 9ef7b9f16951..9e1a44540201 100644 --- a/lib/trace-cmd/trace-input.c +++ b/lib/trace-cmd/trace-input.c @@ -772,14 +772,17 @@ static int read_cpus(struct tracecmd_input *handle) } /** - * tracecmd_read_headers - read the header information from trace.dat + * tracecmd_read_pre_headers - read the header information from trace.dat * @handle: input handle for the trace.dat file * * This reads the trace.dat file for various information. Like the * format of the ring buffer, event formats, ftrace formats, kallsyms - * and printk. + * and printk, but stops before reading cpu and options. + * + * This is needed by the restore operation where the header does not + * have the CPU information yet. */ -int tracecmd_read_headers(struct tracecmd_input *handle) +int tracecmd_read_pre_headers(struct tracecmd_input *handle) { int ret; @@ -815,6 +818,22 @@ int tracecmd_read_headers(struct tracecmd_input *handle) return -1; handle->file_state = TRACECMD_FILE_CMD_LINES; + return 0; +} + +/** + * tracecmd_read_headers - read the header information from trace.dat + * @handle: input handle for the trace.dat file + * + * This reads the trace.dat file for various information. Like the + * format of the ring buffer, event formats, ftrace formats, kallsyms + * and printk. + */ +int tracecmd_read_headers(struct tracecmd_input *handle) +{ + if (tracecmd_read_pre_headers(handle)) + return -1; + if (read_cpus(handle) < 0) return -1; handle->file_state = TRACECMD_FILE_CPU_COUNT; diff --git a/tracecmd/trace-restore.c b/tracecmd/trace-restore.c index 13f803053582..bf6940991178 100644 --- a/tracecmd/trace-restore.c +++ b/tracecmd/trace-restore.c @@ -122,7 +122,7 @@ void trace_restore (int argc, char **argv) if (!ihandle) die("error reading file %s", input); /* make sure headers are ok */ - if (tracecmd_read_headers(ihandle) < 0) + if (tracecmd_read_pre_headers(ihandle) < 0) die("error reading file %s headers", input); handle = tracecmd_copy(ihandle, output);