Hmm. Did you consider setting the ifdefs you can set to always get the POSIX version of strerror_r?
best, Colin On Fri, Oct 5, 2018, at 08:30, Steven Rostedt wrote: > On Tue, 2 Oct 2018 17:55:39 -0400 > Steven Rostedt <[email protected]> wrote: > > > From: "Steven Rostedt (VMware)" <[email protected]> > > > > While working on having PowerTop use libtracevent as a shared object > > library, Tzvetomir hit "str_error_r not defined". This was added by commit > > c3cec9e68f12d ("tools lib traceevent: Use str_error_r()") because > > strerror_r() has two definitions, where one is GNU specific, and the other > > is XSI complient. The strerror_r() is in a wrapper str_error_r() to keep the > > code from having to worry about which compiler is being used. > > > > The problem is that str_error_r() is external to libtraceevent, and not part > > of the library. If it is used as a shared object then the tools using it > > will need to define that function. I do not want that function defined in > > libtraceevent itself, as it is out of scope for that library. > > > > As there's only a single instance of this call, I replaced it with an open > > coded algorithm that uses sys_nerr and sys_errlist error array with > > strncpy() to place the error message in the given buffer. We don't need to > > worry about the errors that strerror_r() returns. If the buffer isn't big > > enough, we simply truncate it. > > > > The sys_nerr and sys_errlist idea was found here: > > > > http://www.club.cc.cmu.edu/~cmccabe/blog_strerror.html > > > > Cc: Colin Patrick McCabe <[email protected]> > > Reported-by: Tzvetomir Stoyanov <[email protected]> > > Signed-off-by: Steven Rostedt (VMware) <[email protected]> > > --- > > Changes since v2: > > > > Use sys_nerr and sys_errlist idea. > > > > tools/lib/traceevent/event-parse.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/tools/lib/traceevent/event-parse.c > > b/tools/lib/traceevent/event-parse.c > > index 7980fc6c3bac..d23d10bc5314 100644 > > --- a/tools/lib/traceevent/event-parse.c > > +++ b/tools/lib/traceevent/event-parse.c > > @@ -18,7 +18,6 @@ > > #include <errno.h> > > #include <stdint.h> > > #include <limits.h> > > -#include <linux/string.h> > > #include <linux/time64.h> > > > > #include <netinet/in.h> > > @@ -6215,7 +6214,13 @@ int tep_strerror(struct tep_handle *pevent > > __maybe_unused, > > const char *msg; > > > > if (errnum >= 0) { > > - str_error_r(errnum, buf, buflen); > > + if (buflen > 0) { > > + if (errnum < sys_nerr) > > + strncpy(buf, sys_errlist[errnum], buflen); > > + else > > + snprintf(buf, buflen, "Unknown error %d", > > errnum); > > + buf[buflen - 1] = 0; > > + } > > Bah, I now get warnings that sys_nerr and sys_errlist are deprecated. > > OK, so going back to just using the racy strerror() should be good > enough, as this incompatibility with strerror_r() is a disaster! > > -- Steve > > > > return 0; > > } > > > C.
