# tep_parse_saved_cmdlines

## 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.
    


## 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
    


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