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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |EXAMPLE |FILES |SEE ALSO |AUTHOR |REPORTING BUGS |LICENSE |RESOURCES |NOTES |COLOPHON | |
LIBTRACEEVENT(3) libtraceevent ManualLIBTRACEEVENT(3)tep_parse_saved_cmdlines, tep_parse_printk_formats, tep_parse_kallsyms - Parsing functions to load mappings
#include <event-parse.h> inttep_parse_saved_cmdlines(struct tep_handle *tep, const char *buf); inttep_parse_printk_formats(struct tep_handle *tep, const char *buf); inttep_parse_kallsyms(struct tep_handle *tep, const char *buf);
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 bybuf) and loads the mapping of the process IDs (pid) to the comm names in thetep 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 stringbuf 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 bybuf) 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 stringbuf 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 bybuf) and load the functions into thetep 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 stringbuf that holds the content of /proc/kallsyms and ends with a nul character (\0).
Thetep_parse_saved_cmdlines() function returns 0 in case of success, or -1 in case of an error. Thetep_parse_printk_formats() function returns 0 in case of success, or -1 in case of an error. Thetep_parse_kallsyms() function returns 0 in case of success, or -1 in case of an error.
... #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; } ...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.
libtraceevent(3),trace-cmd(1),tep_register_comm(3),tep_register_function(3),tep_register_print_string(3)
Steven Rostedt<rostedt@goodmis.org[1]>, author oflibtraceevent.Tzvetomir Stoyanov<tz.stoyanov@gmail.com[2]>, coauthor oflibtraceevent.
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtraceevent is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
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
This page is part of thelibtraceevent (Linux kernel trace event library) project. Information about the project can be found at ⟨https://www.trace-cmd.org/⟩. If you have a bug report for this manual page, see ⟨https://www.trace-cmd.org/⟩. This page was obtained from the project's upstream Git repository ⟨https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git⟩ on 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-05-30.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orglibtraceevent 1.7.3 09/24/2023LIBTRACEEVENT(3)HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |