[Crash-utility] [PATCH 2/2] Fix build if userid does not exist in user database

[Dave Anderson]

----- Original Message -----
> 
> 
> ----- Original Message -----
> > make_build_data uses the output of the id command in order to generate the
> > string in build_data.c indicating who built the program. Unfortunately, the
> > previous parsing code looked for the presence of a ")" in order to
> > determine
> > where the user field ended. If the user is not found in the user database,
> > the output looks more like:
> > uid=59784003 gid=60243 groups=60243
> 
> For the changelog, what does "help -B" show in that case?  Or does the
> build fail?

Hello Sargun,

OK, after looking into this, I see that it causes a segmentation fault on build.

And although I do appreciate your efforts, and welcome your interest, this patch
is a bit of overkill.  This simple patch fixes it:

--- a/configure.c
+++ b/configure.c
@@ -1277,8 +1277,7 @@ make_build_data(char *target)
         p = fgets(inbuf1, 79, fp1);
 
         p = fgets(inbuf2, 79, fp2);
-        p = strstr(inbuf2, ")");
-        p++;
+        p = strstr(inbuf2, " ");
         *p = '\0';
 
         p = fgets(inbuf3, 79, fp3);

Thanks for the report.

Dave




 
> > 
> > Instead, now it just calls the glibc helpers and formats the line based
> > upon those instead of shelling out and trying to parse the output of id.
> > If it cannot retrieve the username, it just sets the UID.
> 
> Ok, that's fine.
> 
> I also seem to recall that coverity scans (or perhaps distro-specific
> compiler flags?) complain about not assigning/looking-at the return
> value fgets().  The old code assigned it to "p" (and ignored it), so
> the fgets() should probably still be assigned to something -- maybe by
> re-introducing "char *p" with an "__attribute__ ((__unused__))".
> 
> Dave
> 
> 
> > 
> > Signed-off-by: Sargun Dhillon <sargun at sargun.me>
> > ---
> >  configure.c | 16 +++++++++-------
> >  1 file changed, 9 insertions(+), 7 deletions(-)
> > 
> > diff --git a/configure.c b/configure.c
> > index 10bc6e1..8ddec66 100644
> > --- a/configure.c
> > +++ b/configure.c
> > @@ -56,6 +56,7 @@
> >  #include <sys/stat.h>
> >  #include <unistd.h>
> >  #include <ctype.h>
> > +#include <pwd.h>
> >  
> >  struct supported_gdb_version;
> >  void build_configure(struct supported_gdb_version *);
> > @@ -1252,7 +1253,7 @@ count_chars(char *s, char c)
> >  void
> >  make_build_data(char *target)
> >  {
> > -	char *p;
> > +	struct passwd *passwd;
> >  	char hostname[MAXSTRLEN];
> >  	char progname[MAXSTRLEN];
> >  	char datebuf[MAXSTRLEN];
> > @@ -1274,14 +1275,15 @@ make_build_data(char *target)
> >  	if (gethostname(hostname, MAXSTRLEN) != 0)
> >  		hostname[0] = '\0';
> >  
> > -	p = fgets(datebuf, 79, fp_date);
> > +	fgets(datebuf, 79, fp_date);
> >  
> > -	p = fgets(idbuf, 79, fp_id);
> > -	p = strstr(idbuf, ")");
> > -	p++;
> > -	*p = '\0';
> > +	passwd = getpwuid(getuid());
> > +	if (passwd)
> > +		sprintf(idbuf, "uid=%d(%s)", passwd->pw_uid, passwd->pw_name);
> > +	else
> > +		sprintf(idbuf, "uid=%d", getuid());
> >  
> > -	p = fgets(gccversionbuf, 79, fp_gcc);
> > +	fgets(gccversionbuf, 79, fp_gcc);
> >  
> >  	lower_case(target_data.program, progname);
> >  
> > --
> > 2.9.3
> > 
> > --
> > Crash-utility mailing list
> > Crash-utility at redhat.com
> > https://www.redhat.com/mailman/listinfo/crash-utility
> > 
>