[LTP] [PATCH v16 1/2] lib: New library function tst_get_free_uid

[Petr Vorel]

> Hi Wei,

> > +uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
> > +
> > +/**
> > + * tst_get_free_uid() - Find a UID not assigned to any user.
> > + * @skip: UID value to skip (pass 0 to skip none).
> > + *
> > + * Scans the password database for the first unused UID starting
> > + * from 1, skipping @skip. Calls tst_brk(TBROK) if no free UID
> > + * is found or a lookup error occurs.
> > + *
> > + * Return: An unused uid_t value.
> > + */
> > +#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
> > +
> >  /*
> >   * Find unassigned gid. The skip argument can be used to ignore e.g. the main
> >   * group of a specific user in case it's not listed in the group file. If you
> > diff --git a/lib/tst_uid.c b/lib/tst_uid.c
> > index b0b087362..47c267bc4 100644
> > --- a/lib/tst_uid.c
> > +++ b/lib/tst_uid.c
> > @@ -5,6 +5,7 @@

> >  #include <sys/types.h>
> >  #include <grp.h>
> > +#include <pwd.h>
> >  #include <errno.h>

> >  #define TST_NO_DEFAULT_MAIN
> > @@ -12,6 +13,33 @@
> >  #include "tst_uid.h"

> >  #define MAX_GID 32767
> > +#define MAX_UID 32767
> > +
> > +uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
> > +{
> > +	uid_t ret;
> > +
> > +	for (ret = 1; ret < MAX_UID; ret++) {
> > +		if (ret == skip)
> > +			continue;
> > +
> > +		errno = 0;
> > +		if (getpwuid(ret))
> > +			continue;


> If you don't mind I'd prefer to use the same approach which is on
> tst_get_free_gid_(), e.g. set errno first:

> 	errno = 0;

> 	for (ret = 1; ret < MAX_UID; ret++) {
> 		if (ret == skip || getpwuid(ret))
> 			continue;

> Reviewed-by: Petr Vorel <pvorel@suse.cz>

> Other than that LGTM.

> Cc Martin in case he wants to add his ack before I merge.

> Kind regards,
> Petr

> > +
> > +		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
> > +			tst_res_(file, lineno, TINFO,
Actually also here TERRNO probably makes sense.

I suggest to merge with following diff:

+++ lib/tst_uid.c
@@ -19,16 +19,14 @@ uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
 {
 	uid_t ret;
 
-	for (ret = 1; ret < MAX_UID; ret++) {
-		if (ret == skip)
-			continue;
+	errno = 0;
 
-		errno = 0;
-		if (getpwuid(ret))
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip || getpwuid(ret))
 			continue;
 
 		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
-			tst_res_(file, lineno, TINFO,
+			tst_res_(file, lineno, TINFO | TERRNO,
 				"Found unused UID %d", (int)ret);
 			return ret;
 		}