id: support multiple specified users

  $ id root nobody
  uid=0(root) gid=0(root) groups=0(root)
  uid=99(nobody) gid=99(nobody) groups=99(nobody)

* src/id.c (main): Make variables opt_zero, just_group_list,
just_group, use_real, just_user global to be used in a new
function.
(print_stuff): New function that will print user and group
information for the specified USER.
When using -G option delimit each record with two NULs.
Restructure the code in the file to have global variables
followed by functions.
* tests/id/zero.sh: Add test cases to check the usage
of -z option with multiple users.
* tests/id/uid.sh: Add a test case to ensure all users
are queried in the presence of errors.
* doc/coreutils.texi: Document the interface changes.
* NEWS: Mention the new feature.

2 files changed, 42 insertions, 0 deletions

diff --git a/tests/id/uid.sh b/tests/id/uid.sh
index 61d313778..9d856433d 100755
--- a/tests/id/uid.sh
+++ b/tests/id/uid.sh
@@ -24,6 +24,11 @@ user=$(id -nu) || fail=1
 # Ensure the empty user spec is discarded
 returns_ 1 id '' || fail=1
 
+# Ensure we don't exit early, and process all users
+id $user > user_out || fail=1
+returns_ 1 id '' $user >multi_user_out || fail=1
+compare user_out multi_user_out || fail=1
+
 for mode in '' '-G' '-g'; do
   id $mode $user > user_out || fail=1 # lookup name for comparison
 
diff --git a/tests/id/zero.sh b/tests/id/zero.sh
index f183e18f8..d0cf44c53 100755
--- a/tests/id/zero.sh
+++ b/tests/id/zero.sh
@@ -63,4 +63,41 @@ printf '\n' >> out || framework_failure_
 tr '\0' ' ' < out > out2 || framework_failure_
 compare exp out2 || fail=1
 
+# multiuser testing with -z
+# test if the options work, these tests should pass if the above tests
+# do.
+
+for o in g gr u ur ; do
+  for n in '' n ; do
+    id -${o}${n}  $users >> tmp1 ||
+      { test $? -ne 1 || test -z "$n" && fail=1; }
+    id -${o}${n}z $users  > tmp2 ||
+      { test $? -ne 1 || test -z "$n" && fail=1; }
+    tr '\0' '\n' < tmp2 >> tmp3
+  done
+done
+compare tmp1 tmp3 || fail=1
+
+# Separate checks when we are testing for multiple users && -G.
+# This is done because we terminate the records with two NULs
+# instead of a regular single NUL.
+
+NL='
+'
+
+for o in G Gr ; do
+  for n in '' n ; do
+    id -${o}${n}  $users >> gtmp1 ||
+      { test $? -ne 1 || test -z "$n" && fail=1; }
+    id -${o}${n}z $users  > gtmp2 ||
+      { test $? -ne 1 || test -z "$n" && fail=1; }
+    # we replace all NULs with spaces, the result we get is there are two
+    # consecutive spaces instead of two NUL's, we pass this to sed
+    # to replace more than 1 space with a newline. This is ideally where a new
+    # line should be. This should make the output similar to without -z.
+    tr '\0' ' ' < gtmp2 | sed "s/  /\\$NL/g" >> gtmp3
+  done
+done
+compare gtmp1 gtmp3 || fail=1
+
 Exit $fail