hi steve / tzvetomir,
If there are any dependencies for merging this patch, please let me
know. If not, please merge this
patch. will give the man page and test code in separate patches, as
suggested by tzvetmoir.
Thanks,
sameer
On Thu, Mar 18, 2021 at 10:52 PM Tzvetomir Stoyanov
<tz.stoyanov@xxxxxxxxx> wrote:
>
> On Thu, Mar 18, 2021 at 6:38 PM Sameeruddin shaik
> <sameeruddin.shaik8@xxxxxxxxx> wrote:
> >
> > This new API will write the function filters into the
> > set_ftrace_filter file.
> >
> > tracefs_function_filter()
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=210643
> >
> > Signed-off-by: Sameeruddin shaik <sameeruddin.shaik8@xxxxxxxxx>
> > ---
> > Addressed the realloc comments
> > diff --git a/include/tracefs.h b/include/tracefs.h
> > index f3eec62..c1f07b0 100644
> > --- a/include/tracefs.h
> > +++ b/include/tracefs.h
> > @@ -145,5 +145,6 @@ bool tracefs_option_is_enabled(struct tracefs_instance *instance, enum tracefs_o
> > int tracefs_option_enable(struct tracefs_instance *instance, enum tracefs_option_id id);
> > int tracefs_option_diasble(struct tracefs_instance *instance, enum tracefs_option_id id);
> > const char *tracefs_option_name(enum tracefs_option_id id);
> > -
> > +int tracefs_function_filter(struct tracefs_instance *instance, const char **filters,
> > + const char *module, bool reset, const char ***errs);
> > #endif /* _TRACE_FS_H */
> > diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c
> > index e2dfc7b..4f8bcdc 100644
> > --- a/src/tracefs-tools.c
> > +++ b/src/tracefs-tools.c
> > @@ -18,6 +18,7 @@
> > #include "tracefs-local.h"
> >
> > #define TRACE_CTRL "tracing_on"
> > +#define TRACE_FILTER "set_ftrace_filter"
> >
> > static const char * const options_map[] = {
> > "unknown",
> > @@ -387,3 +388,113 @@ void tracefs_option_clear(struct tracefs_options_mask *options, enum tracefs_opt
> > if (options && id > TRACEFS_OPTION_INVALID)
> > options->mask &= ~(1ULL << (id - 1));
> > }
> > +
> > +static int controlled_write(const char *filter_path, const char **filters,
> > + const char *module, bool reset, const char ***errs)
> > +{
> > + int flags = reset ? O_TRUNC : O_APPEND;
> > + const char **temp = NULL;
> > + const char **e = NULL;
> > + char *each_str = NULL;
> > + int write_size = 0;
> > + int size = 0;
> > + int fd = -1;
> > + int ret = 0;
> > + int j = 0;
> > + int i;
> > +
> > + fd = open(filter_path, O_WRONLY | flags);
> > + if (fd < 0)
> > + return 1;
> > +
> > + for (i = 0; filters[i]; i++) {
> > + if (module)
> > + write_size = asprintf(&each_str, "%s:mod:%s ", filters[i], module);
> > + else
> > + write_size = asprintf(&each_str, "%s ", filters[i]);
> > + if (write_size < 0) {
> > + ret = 1;
> > + goto error;
> > + }
> > + size = write(fd, each_str, write_size);
> > + /* compare written bytes*/
> > + if (size < write_size) {
> > + if (errs) {
> > + temp = realloc(e, (j + 1) * (sizeof(char *)));
> > + if (!temp) {
> > + free(e);
> > + ret = 1;
> > + goto error;
> > + } else
> > + e = temp;
> > +
> > + e[j++] = filters[i];
> > + ret -= 1;
> > + }
> > + }
> > + free(each_str);
> > + each_str = NULL;
> > + }
> > + if (errs) {
> > + temp = realloc(e, (j + 1) * (sizeof(char *)));
> > + if (!temp) {
> > + free(e);
> > + ret = 1;
> > + goto error;
> > + } else
> > + e = temp;
> > + e[j] = NULL;
> > + *errs = e;
> > + }
> > + error:
> > + if (each_str)
> > + free(each_str);
> > + close(fd);
> > + return ret;
> > +}
> > +
> > +/**
> > + * tracefs_function_filter - write to set_ftrace_filter file to trace
> > + * particular functions
> > + * @instance: ftrace instance, can be NULL for top tracing instance
> > + * @filters: An array of function names ending with a NULL pointer
> > + * @module: Module to be traced
> > + * @reset: set to true to reset the file before applying the filter
> > + * @errs: A pointer to array of constant strings that will be allocated
> > + * on negative return of this function, pointing to the filters that
> > + * failed.May be NULL, in which case this field will be ignored.
> > + *
> > + * The @filters is an array of strings, where each string will be used
> > + * to set a function or functions to be traced.
> > + *
> > + * If @reset is true, then all functions in the filter are cleared
> > + * before adding functions from @filters. Otherwise, the functions set
> > + * by @filters will be appended to the filter file
> > + *
> > + * returns -x on filter errors (where x is number of failed filter
> > + * srtings) and if @errs is not NULL will be an allocated string array
> > + * pointing to the strings in @filters that failed and must be freed
> > + * with free().
> > + *
> > + * returns 1 on general errors not realted to setting the filter.
> > + * @errs is not set even if supplied.
> > + *
> > + * return 0 on success and @errs is not set.
> > + */
> > +int tracefs_function_filter(struct tracefs_instance *instance, const char **filters,
> > + const char *module, bool reset, const char ***errs)
> > +{
> > + char *ftrace_filter_path;
> > + int ret = 0;
> > +
> > + if (!filters)
> > + return 1;
> > +
> > + ftrace_filter_path = tracefs_instance_get_file(instance, TRACE_FILTER);
> > + if (!ftrace_filter_path)
> > + return 1;
> > +
> > + ret = controlled_write(ftrace_filter_path, filters, module, reset, errs);
> > + tracefs_put_tracing_file(ftrace_filter_path);
> > + return ret;
> > +}
> > --
> > 2.7.4
> >
>
> Looks good to me.
> Thanks Sameer!
> Acked-by: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx>
>
>
> --
> Tzvetomir (Ceco) Stoyanov
> VMware Open Source Technology Center
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