| Message ID | 20210330005248.694899644@goodmis.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8340f261dee9282c8f210004a26f67520e698459 |
| Headers | show |
| Series | libtracefs: Add tracefs_function_filter() | expand |
On Tue, Mar 30, 2021 at 3:54 AM Steven Rostedt <rostedt@goodmis.org> wrote: > > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org> > > Instead of having a separate boolean to tell tracefs_function_filter() to > reset the file upon opening, make it a flag instead. This way other > booleans can be passed into the function without having to extend the > parameters. > > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> > --- > Documentation/libtracefs-function-filter.txt | 26 ++++++++++++++------ > include/tracefs.h | 10 +++++++- > src/tracefs-tools.c | 19 ++++++++------ > 3 files changed, 38 insertions(+), 17 deletions(-) > > diff --git a/Documentation/libtracefs-function-filter.txt b/Documentation/libtracefs-function-filter.txt > index 88aa3b923d54..5b55a72727c8 100644 > --- a/Documentation/libtracefs-function-filter.txt > +++ b/Documentation/libtracefs-function-filter.txt > @@ -11,7 +11,7 @@ SYNOPSIS > -- > *#include <tracefs.h>* > > -int *tracefs_function_filter*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]pass:[*]_filters_, const char pass:[*]_module_, bool _reset_, const char pass:[*]pass:[*]pass:[*]_errs_); > +int *tracefs_function_filter*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]pass:[*]_filters_, const char pass:[*]_module_, int _flags_, const char pass:[*]pass:[*]pass:[*]_errs_); > -- > > DESCRIPTION > @@ -25,18 +25,17 @@ _filters_, which is an array of the strings that represent a list of filters tha > be applied to define what functions are to be traced and The array must end > with a NULL pointer. > _module_ , name of the module to be traced (or NULL for all functions), > -_reset_ if set will clear the current set of filters and then apply the > -filter list, otherwise the list of filters are added to the current set of > -filters, > +_flags_ which holds control knobs on how the filters will be handled (see *FLAGS*) > +section below, > _errs_, is a pointer to an array of strings, which will be allocated if > any of filters fail to match any available function, If _errs_ is NULL, it will > be ignored. > > A filter in the array of _filters_ may be either a straight match of a > -function, a glob or regex(3). a glob is where '*' matches zero or more > +function, a glob or regex(3). a glob is where 'pass:[*]' matches zero or more > characters, '?' will match zero or one character, and '.' only matches a > period. If the filter is determined to be a regex (where it contains > -anything other than alpha numeric characters, or '.', '*', '?') the filter > +anything other than alpha numeric characters, or '.', 'pass:[*]', '?') the filter > will be processed as a regex(3) following the rules of regex(3), and '.' is > not a period, but will match any one character. To force a regular > expression, either prefix the filter with a '^' or append it with a '$' as > @@ -44,6 +43,17 @@ all filters will act as complete matches of functions anyway. > > returns 0 on success, 1 or -x (where x is an integer) on error. > > +FLAGS > +----- > + > +The _flags_ parameter may have the following set, or be zero. > + > +*TRACEFS_FL_RESET* : > +If _flags_ contains *TRACEFS_FL_RESET*, then it will clear the filters that > +are currently set before applying the list of filters from _filters_. Otherwise, > +the list of filters from _filters_ will be added to the current set of filters > +already enabled. > + > RETURN VALUE > ------------ > return 0 on success, if there is error, it will return 1 for general errors or > @@ -66,7 +76,7 @@ int main(int argc, char *argv[]) > { > struct tracefs_instance *inst = tracefs_instance_create(INST); > const char **errs = NULL; > - bool reset = 1; > + int flags = TRACEFS_FL_RESET; > int ret; > int i = 0; > > @@ -74,7 +84,7 @@ int main(int argc, char *argv[]) > /* Error creating new trace instance */ > } > > - ret = tracefs_function_filter(inst, filters, NULL, reset, &errs); > + ret = tracefs_function_filter(inst, filters, NULL, flags, &errs); > > if (ret < 0 && errs) { > while (errs[i]) > diff --git a/include/tracefs.h b/include/tracefs.h > index 9477fdb14c5a..5193d46f41f5 100644 > --- a/include/tracefs.h > +++ b/include/tracefs.h > @@ -145,6 +145,14 @@ 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); > + > +/* > + * RESET - Reset on opening filter file (O_TRUNC) > + */ > +enum { > + TRACEFS_FL_RESET = (1 << 0), > +}; > + > int tracefs_function_filter(struct tracefs_instance *instance, const char **filters, > - const char *module, bool reset, const char ***errs); > + const char *module, unsigned int flags, const char ***errs); > #endif /* _TRACE_FS_H */ > diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c > index 8f2130948fe0..6d03b4856a63 100644 > --- a/src/tracefs-tools.c > +++ b/src/tracefs-tools.c > @@ -835,7 +835,7 @@ static int write_func_list(int fd, struct func_list *list) > * @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 > + * @flags: flags on modifying the filter file > * @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. > @@ -843,9 +843,11 @@ static int write_func_list(int fd, struct func_list *list) > * 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 > + * @flags: > + * TRACEFS_FL_RESET - will clear the functions in the filter file > + * before applying the @filters. This flag is ignored > + * if this function is called again when the previous > + * call had TRACEFS_FL_CONTINUE set. > * > * 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 > @@ -858,12 +860,13 @@ static int write_func_list(int fd, struct func_list *list) > * 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) > + const char *module, unsigned int flags, const char ***errs) > { > struct func_filter *func_filters; > struct func_list *func_list = NULL; > char *ftrace_filter_path; > - int flags; > + bool reset = flags & TRACEFS_FL_RESET; > + int open_flags; > int ret; > int fd; > > @@ -887,9 +890,9 @@ int tracefs_function_filter(struct tracefs_instance *instance, const char **filt > if (!ftrace_filter_path) > goto out_free; > > - flags = reset ? O_TRUNC : O_APPEND; > + open_flags = reset ? O_TRUNC : O_APPEND; > > - fd = open(ftrace_filter_path, O_WRONLY | flags); > + fd = open(ftrace_filter_path, O_WRONLY | open_flags); > tracefs_put_tracing_file(ftrace_filter_path); > if (fd < 0) > goto out_free; > -- > 2.30.1 > > It will be useful to allow calling the API with RESET flag set and no filters, just to reset the current filters without adding new: tracefs_function_filter(NULL, NULL, NULL,TRACEFS_FL_RESET, NULL); could be a valid call to reset filters in the top trace instance. -- Tzvetomir (Ceco) Stoyanov VMware Open Source Technology Center
On Tue, 30 Mar 2021 17:29:35 +0300 Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote: > It will be useful to allow calling the API with RESET flag set and no > filters, just to reset the current filters without adding new: > tracefs_function_filter(NULL, NULL, NULL,TRACEFS_FL_RESET, NULL); > could be a valid call to reset filters in the top trace instance. Agreed. I planned on adding a patch to do just that. -- Steve
diff --git a/Documentation/libtracefs-function-filter.txt b/Documentation/libtracefs-function-filter.txt index 88aa3b923d54..5b55a72727c8 100644 --- a/Documentation/libtracefs-function-filter.txt +++ b/Documentation/libtracefs-function-filter.txt @@ -11,7 +11,7 @@ SYNOPSIS -- *#include <tracefs.h>* -int *tracefs_function_filter*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]pass:[*]_filters_, const char pass:[*]_module_, bool _reset_, const char pass:[*]pass:[*]pass:[*]_errs_); +int *tracefs_function_filter*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]pass:[*]_filters_, const char pass:[*]_module_, int _flags_, const char pass:[*]pass:[*]pass:[*]_errs_); -- DESCRIPTION @@ -25,18 +25,17 @@ _filters_, which is an array of the strings that represent a list of filters tha be applied to define what functions are to be traced and The array must end with a NULL pointer. _module_ , name of the module to be traced (or NULL for all functions), -_reset_ if set will clear the current set of filters and then apply the -filter list, otherwise the list of filters are added to the current set of -filters, +_flags_ which holds control knobs on how the filters will be handled (see *FLAGS*) +section below, _errs_, is a pointer to an array of strings, which will be allocated if any of filters fail to match any available function, If _errs_ is NULL, it will be ignored. A filter in the array of _filters_ may be either a straight match of a -function, a glob or regex(3). a glob is where '*' matches zero or more +function, a glob or regex(3). a glob is where 'pass:[*]' matches zero or more characters, '?' will match zero or one character, and '.' only matches a period. If the filter is determined to be a regex (where it contains -anything other than alpha numeric characters, or '.', '*', '?') the filter +anything other than alpha numeric characters, or '.', 'pass:[*]', '?') the filter will be processed as a regex(3) following the rules of regex(3), and '.' is not a period, but will match any one character. To force a regular expression, either prefix the filter with a '^' or append it with a '$' as @@ -44,6 +43,17 @@ all filters will act as complete matches of functions anyway. returns 0 on success, 1 or -x (where x is an integer) on error. +FLAGS +----- + +The _flags_ parameter may have the following set, or be zero. + +*TRACEFS_FL_RESET* : +If _flags_ contains *TRACEFS_FL_RESET*, then it will clear the filters that +are currently set before applying the list of filters from _filters_. Otherwise, +the list of filters from _filters_ will be added to the current set of filters +already enabled. + RETURN VALUE ------------ return 0 on success, if there is error, it will return 1 for general errors or @@ -66,7 +76,7 @@ int main(int argc, char *argv[]) { struct tracefs_instance *inst = tracefs_instance_create(INST); const char **errs = NULL; - bool reset = 1; + int flags = TRACEFS_FL_RESET; int ret; int i = 0; @@ -74,7 +84,7 @@ int main(int argc, char *argv[]) /* Error creating new trace instance */ } - ret = tracefs_function_filter(inst, filters, NULL, reset, &errs); + ret = tracefs_function_filter(inst, filters, NULL, flags, &errs); if (ret < 0 && errs) { while (errs[i]) diff --git a/include/tracefs.h b/include/tracefs.h index 9477fdb14c5a..5193d46f41f5 100644 --- a/include/tracefs.h +++ b/include/tracefs.h @@ -145,6 +145,14 @@ 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); + +/* + * RESET - Reset on opening filter file (O_TRUNC) + */ +enum { + TRACEFS_FL_RESET = (1 << 0), +}; + int tracefs_function_filter(struct tracefs_instance *instance, const char **filters, - const char *module, bool reset, const char ***errs); + const char *module, unsigned int flags, const char ***errs); #endif /* _TRACE_FS_H */ diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c index 8f2130948fe0..6d03b4856a63 100644 --- a/src/tracefs-tools.c +++ b/src/tracefs-tools.c @@ -835,7 +835,7 @@ static int write_func_list(int fd, struct func_list *list) * @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 + * @flags: flags on modifying the filter file * @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. @@ -843,9 +843,11 @@ static int write_func_list(int fd, struct func_list *list) * 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 + * @flags: + * TRACEFS_FL_RESET - will clear the functions in the filter file + * before applying the @filters. This flag is ignored + * if this function is called again when the previous + * call had TRACEFS_FL_CONTINUE set. * * 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 @@ -858,12 +860,13 @@ static int write_func_list(int fd, struct func_list *list) * 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) + const char *module, unsigned int flags, const char ***errs) { struct func_filter *func_filters; struct func_list *func_list = NULL; char *ftrace_filter_path; - int flags; + bool reset = flags & TRACEFS_FL_RESET; + int open_flags; int ret; int fd; @@ -887,9 +890,9 @@ int tracefs_function_filter(struct tracefs_instance *instance, const char **filt if (!ftrace_filter_path) goto out_free; - flags = reset ? O_TRUNC : O_APPEND; + open_flags = reset ? O_TRUNC : O_APPEND; - fd = open(ftrace_filter_path, O_WRONLY | flags); + fd = open(ftrace_filter_path, O_WRONLY | open_flags); tracefs_put_tracing_file(ftrace_filter_path); if (fd < 0) goto out_free;