NAME

       tep_parse_saved_cmdlines, tep_parse_printk_formats, tep_parse_kallsyms - Parsing functions
       to load mappings

SYNOPSIS

       #include <event-parse.h>

       int tep_parse_saved_cmdlines(struct tep_handle *tep, const char *buf);
       int tep_parse_printk_formats(struct tep_handle *tep, const char *buf);
       int tep_parse_kallsyms(struct tep_handle *tep, const char *buf);

DESCRIPTION

       tep_parse_saved_cmdlines() is a helper function to parse content in the tracefs file
       system of the "saved_cmdlines" file (stored in a string buffer passed in by buf) and loads
       the mapping of the process IDs (pid) to the comm names in the tep handler. The events
       store the pid and this is used to be able to show the process names associated to those
       process ids. It parses the string buf that holds the content of saved_cmdlines and ends
       with a nul character (\0).

       tep_parse_printk_formats() is a helper function to parse content in the tracefs file
       system of the "printk_formats" file (stored in a string buffer passed in by buf) and loads
       the mapping of addresses of strings that may be referenced by events. Events only store
       the address of constant strings in the kernel, and the mapping of their address to the
       string is exported to user space in the printk_formats file. It parses the string buf that
       holds the content of printk_formats and ends with a nul character (\0).

       tep_parse_kallsyms() is a helper function to parse the Linux kernel /proc/kallsyms format
       (stored in a string buffer passed in by buf) and load the functions into the tep handler
       such that function IP addresses can be mapped to their name when parsing events with %pS
       in the print format field. It parses the string buf that holds the content of
       /proc/kallsyms and ends with a nul character (\0).

RETURN VALUE

       The tep_parse_saved_cmdlines() function returns 0 in case of success, or -1 in case of an
       error.

       The tep_parse_printk_formats() function returns 0 in case of success, or -1 in case of an
       error.

       The tep_parse_kallsyms() function returns 0 in case of success, or -1 in case of an error.

EXAMPLE

           ...
           #include <event-parse.h>
           #include <tracefs.h>
           #include <stdlib.h>

           int load_cmdlines(struct tep_handle *tep)
           {
                   char *buf = NULL;
                   int r;

                   buf = tracefs_instance_file_read(NULL, "saved_cmdlines", NULL);
                   if (!buf)
                           return -1;
                   r = tep_parse_saved_cmdlines(tep, buf);
                   free(buf);
                   return r;
           }

           int load_print_strings(struct tep_handle *tep)
           {
                   char *buf = NULL;
                   int r;

                   buf = tracefs_instance_file_read(NULL, "printk_formats", NULL);
                   if (!buf)
                           return -1;
                   r = tep_parse_printk_formats(tep, buf);
                   free(buf);
                   return r;
           }

           int load_kallsyms(struct tep_handle *tep)
           {
                   char *line = NULL;
                   char *buf = NULL;
                   size_t sz = 0;
                   FILE *fp;
                   int len = 0;
                   int r;

                   fp = fopen("/proc/kallsyms", "r");
                   while ((r = getline(&line, &sz, fp)) >= 0) {
                           buf = realloc(buf, len + r + 1);
                           memcpy(buf + len, line, r);
                           len += r;
                   }
                   free(line);
                   fclose(fp);
                   if (!buf)
                           return -1;
                   buf[len] = 0;

                   r = tep_parse_kallsyms(tep, buf);
                   free(buf);
                   return r;
           }
           ...

FILES

           event-parse.h
                   Header file to include in order to have access to the library APIs.
           -ltraceevent
                   Linker switch to add when building a program that uses the library.

SEE ALSO

       libtraceevent(3), trace-cmd(1), tep_register_comm(3), tep_register_function(3),
       tep_register_print_string(3)

AUTHOR

           Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
           Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, coauthor of libtraceevent.

REPORTING BUGS

       Report bugs to <linux-trace-devel@vger.kernel.org[3]>

LICENSE

       libtraceevent is Free Software licensed under the GNU LGPL 2.1

RESOURCES

       https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/

NOTES

        1. rostedt@goodmis.org
           mailto:rostedt@goodmis.org

        2. tz.stoyanov@gmail.com
           mailto:tz.stoyanov@gmail.com

        3. linux-trace-devel@vger.kernel.org
           mailto:linux-trace-devel@vger.kernel.org