[PATCH v2] id: add feature to accept multiple usernames

[Achilles Gaikwad]

Adds a feature to id command to accept multiple usernames and/or uid
as arguments.

$ 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 varibles 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 consequent NULs.
Restructure the code in the file to have global variables followed by
functions to make the file look pretty.
* tests/id/zero.sh: Add test cases to check the usage of -z option with
multiple users.
* doc/coreutils.texi: add minor documentation change to reflect the
number of inputs that may be given.

Signed-off-by: Achilles Gaikwad <***@redhat.com>
---
doc/coreutils.texi | 2 +-
src/id.c | 171 +++++++++++++++++++++++++--------------------
tests/id/zero.sh | 34 +++++++++
3 files changed, 131 insertions(+), 76 deletions(-)

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 10fd023d8..f2d58b46d 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -15200,7 +15200,7 @@ logins, groups, and so forth.
running it if no user is specified. Synopsis:

@example
-id [@var{option}]@dots{} [@var{user}]
+id [@var{option}]@dots{} [@var{user}]@dots{}
@end example

@var{user} can be either a user ID or a name, with name look-up
diff --git a/src/id.c b/src/id.c
index be0758059..e60803894 100644
--- a/src/id.c
+++ b/src/id.c
@@ -43,10 +43,20 @@

/* If nonzero, output only the SELinux context. */
static bool just_context = 0;
-
-static void print_user (uid_t uid);
-static void print_full_info (const char *username);
-
+/* If true, delimit entries with NUL characters, not whitespace */
+bool opt_zero = false;
+/* If true, output the list of all group IDs. -G */
+bool just_group_list = false;
+/* If true, output only the group ID(s). -g */
+bool just_group = false;
+/* If true, output real UID/GID instead of default effective UID/GID. -r */
+bool use_real = false;
+/* If true, output only the user ID(s). -u */
+bool just_user = false;
+/* True unless errors have been encountered. */
+static bool ok = true;
+/* If true, we are using multiple users. Terminate -G with double NUL. */
+static bool multiple_users = false;
/* If true, output user/group name instead of ID number. -n */
static bool use_name = false;

@@ -54,13 +64,14 @@ static bool use_name = false;
static uid_t ruid, euid;
static gid_t rgid, egid;

-/* True unless errors have been encountered. */
-static bool ok = true;
-
/* The SELinux context. Start with a known invalid value so print_full_info
knows when 'context' has not been set to a meaningful value. */
static char *context = NULL;

+static void print_user (uid_t uid);
+static void print_full_info (const char *username);
+static void print_stuff(const char *pw_name);
+
static struct option const longopts[] =
{
{"context", no_argument, NULL, 'Z'},
@@ -82,9 +93,9 @@ usage (int status)
emit_try_help ();
else
{
- printf (_("Usage: %s [OPTION]... [USER]\n"), program_name);
+ printf (_("Usage: %s [OPTION]... [USER]...\n"), program_name);
fputs (_("\
-Print user and group information for the specified USER,\n\
+Print user and group information for the each specified USER,\n\
or (when USER omitted) for the current user.\n\
\n"),
stdout);
@@ -116,18 +127,8 @@ main (int argc, char **argv)
int optc;
int selinux_enabled = (is_selinux_enabled () > 0);
bool smack_enabled = is_smack_enabled ();
- bool opt_zero = false;
char *pw_name = NULL;

- /* If true, output the list of all group IDs. -G */
- bool just_group_list = false;
- /* If true, output only the group ID(s). -g */
- bool just_group = false;
- /* If true, output real UID/GID instead of default effective UID/GID. -r */
- bool use_real = false;
- /* If true, output only the user ID(s). -u */
- bool just_user = false;
-
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
@@ -185,11 +186,6 @@ main (int argc, char **argv)
}

size_t n_ids = argc - optind;
- if (1 < n_ids)
- {
- error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
- usage (EXIT_FAILURE);
- }

if (n_ids && just_context)
die (EXIT_FAILURE, 0,
@@ -228,29 +224,44 @@ main (int argc, char **argv)
die (EXIT_FAILURE, 0, _("can't get process context"));
}

- if (n_ids == 1)
- {
- struct passwd *pwd = NULL;
- const char *spec = argv[optind];
- /* Disallow an empty spec here as parse_user_spec() doesn't
- give an error for that as it seems it's a valid way to
- specify a noop or "reset special bits" depending on the system. */
- if (*spec)
- {
- if (parse_user_spec (spec, &euid, NULL, NULL, NULL) == NULL)
- {
- /* parse_user_spec will only extract a numeric spec,
- so we lookup that here to verify and also retrieve
- the PW_NAME used subsequently in group lookup. */
- pwd = getpwuid (euid);
- }
- }
- if (pwd == NULL)
- die (EXIT_FAILURE, 0, _("%s: no such user"), quote (spec));
- pw_name = xstrdup (pwd->pw_name);
- ruid = euid = pwd->pw_uid;
- rgid = egid = pwd->pw_gid;
- }
+ if (n_ids >= 1)
+ {
+ multiple_users = n_ids > 1 ? true : false;
+ /* Changing the value of n_ids to the last index in the array where we
+ have the last possible user id. This helps us because we don't have
+ to declare a different variable to keep a track of where the last username
+ lies in argv[]. */
+ n_ids += optind;
+ /* For each username/userid to get its pw_name field */
+ for (; optind < n_ids; optind++)
+ {
+ struct passwd *pwd = NULL;
+ const char *spec = argv[optind];
+ /* Disallow an empty spec here as parse_user_spec() doesn't
+ give an error for that as it seems it's a valid way to
+ specify a noop or "reset special bits" depending on the system. */
+ if (*spec) {
+ if (parse_user_spec(spec, &euid, NULL, NULL, NULL) == NULL)
+ {
+ /* parse_user_spec will only extract a numeric spec,
+ so we lookup that here to verify and also retrieve
+ the PW_NAME used subsequently in group lookup. */
+ pwd = getpwuid(euid);
+ }
+ }
+ if (pwd == NULL)
+ {
+ error (0, errno, _("%s: no such user"), quote (argv[optind]));
+ ok &= false;
+ continue;
+ }
+ pw_name = xstrdup(pwd->pw_name);
+ ruid = euid = pwd->pw_uid;
+ rgid = egid = pwd->pw_gid;
+ print_stuff(pw_name);
+ IF_LINT (free (pw_name));
+ }
+ }
else
{
/* POSIX says identification functions (getuid, getgid, and
@@ -289,34 +300,10 @@ main (int argc, char **argv)
if (rgid == NO_GID && errno)
die (EXIT_FAILURE, errno, _("cannot get real GID"));
}
+ print_stuff(pw_name);
+ IF_LINT (free (pw_name));
}

- if (just_user)
- {
- print_user (use_real ? ruid : euid);
- }
- else if (just_group)
- {
- if (!print_group (use_real ? rgid : egid, use_name))
- ok = false;
- }
- else if (just_group_list)
- {
- if (!print_group_list (pw_name, ruid, rgid, egid, use_name,
- opt_zero ? '\0' : ' '))
- ok = false;
- }
- else if (just_context)
- {
- fputs (context, stdout);
- }
- else
- {
- print_full_info (pw_name);
- }
- putchar (opt_zero ? '\0' : '\n');
-
- IF_LINT (free (pw_name));
return ok ? EXIT_SUCCESS : EXIT_FAILURE;
}

@@ -356,7 +343,7 @@ print_user (uid_t uid)
{
error (0, 0, _("cannot find name for user ID %s"),
uidtostr (uid));
- ok = false;
+ ok &= false;
}
}

@@ -415,7 +402,7 @@ print_full_info (const char *username)
quote (username));
else
error (0, errno, _("failed to get groups for the current process"));
- ok = false;
+ ok &= false;
return;
}

@@ -438,3 +425,37 @@ print_full_info (const char *username)
if (context)
printf (_(" context=%s"), context);
}
+
+/* Print information about the user based on the arguments passed. */
+
+static void
+print_stuff(const char *pw_name)
+{
+ if (just_user)
+ print_user (use_real ? ruid : euid);
+
+ /* print_group and print_group_lists functions return true on successful
+ execution but false if something goes wrong. We then AND this value with
+ the current value of 'ok' because we want to know if one of the previous
+ users faced a problem in these functions. This value of 'ok' is later used
+ to understand what status program should exit with. */
+ else if (just_group)
+ ok &= print_group (use_real ? rgid : egid, use_name);
+ else if (just_group_list)
+ ok &= print_group_list (pw_name, ruid, rgid, egid,
+ use_name, opt_zero ? '\0' : ' ');
+ else if (just_context)
+ fputs (context, stdout);
+ else
+ print_full_info (pw_name);
+ /* When printing records for more than 1 user, at the end of groups
+ of each user terminate the record with two consequent NUL characters
+ to make parsing and distinguishing between two records possible. */
+ if (opt_zero && just_group_list && multiple_users)
+ {
+ putchar('\0');
+ putchar('\0');
+ }
+ else
+ putchar (opt_zero ? '\0' : '\n');
+}
diff --git a/tests/id/zero.sh b/tests/id/zero.sh
index f183e18f8..7a94edde1 100755
--- a/tests/id/zero.sh
+++ b/tests/id/zero.sh
@@ -63,4 +63,38 @@ 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
+
+# Seperate checks when we are testing for multiple users && -G.
+# This is done because we terminate the records with two consequent
+# NULs instead of the regular single NUL.
+
+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
+ # consequent spaces instead of two consequent 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/ \+ /\n/g' >> gtmp3
+ done
+done
+compare gtmp1 gtmp3 || fail=1
+
Exit $fail

[Achilles Gaikwad]

Hello,

Any thoughts about this?

Best,
- Achilles

Post by Achilles Gaikwad
Adds a feature to id command to accept multiple usernames and/or uid
as arguments.
$ 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 varibles 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 consequent NULs.
Restructure the code in the file to have global variables followed by
functions to make the file look pretty.
* tests/id/zero.sh: Add test cases to check the usage of -z option with
multiple users.
* doc/coreutils.texi: add minor documentation change to reflect the
number of inputs that may be given.
---
doc/coreutils.texi | 2 +-
src/id.c | 171 +++++++++++++++++++++++++--------------------
tests/id/zero.sh | 34 +++++++++
3 files changed, 131 insertions(+), 76 deletions(-)
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 10fd023d8..f2d58b46d 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -15200,7 +15200,7 @@ logins, groups, and so forth.
@example
@end example
@var{user} can be either a user ID or a name, with name look-up
diff --git a/src/id.c b/src/id.c
index be0758059..e60803894 100644
--- a/src/id.c
+++ b/src/id.c
@@ -43,10 +43,20 @@
/* If nonzero, output only the SELinux context. */
static bool just_context = 0;
-
-static void print_user (uid_t uid);
-static void print_full_info (const char *username);
-
+/* If true, delimit entries with NUL characters, not whitespace */
+bool opt_zero = false;
+/* If true, output the list of all group IDs. -G */
+bool just_group_list = false;
+/* If true, output only the group ID(s). -g */
+bool just_group = false;
+/* If true, output real UID/GID instead of default effective UID/GID. -r */
+bool use_real = false;
+/* If true, output only the user ID(s). -u */
+bool just_user = false;
+/* True unless errors have been encountered. */
+static bool ok = true;
+/* If true, we are using multiple users. Terminate -G with double NUL. */
+static bool multiple_users = false;
/* If true, output user/group name instead of ID number. -n */
static bool use_name = false;
@@ -54,13 +64,14 @@ static bool use_name = false;
static uid_t ruid, euid;
static gid_t rgid, egid;
-/* True unless errors have been encountered. */
-static bool ok = true;
-
/* The SELinux context. Start with a known invalid value so print_full_info
knows when 'context' has not been set to a meaningful value. */
static char *context = NULL;
+static void print_user (uid_t uid);
+static void print_full_info (const char *username);
+static void print_stuff(const char *pw_name);
+
static struct option const longopts[] =
{
{"context", no_argument, NULL, 'Z'},
@@ -82,9 +93,9 @@ usage (int status)
emit_try_help ();
else
{
- printf (_("Usage: %s [OPTION]... [USER]\n"), program_name);
+ printf (_("Usage: %s [OPTION]... [USER]...\n"), program_name);
fputs (_("\
-Print user and group information for the specified USER,\n\
+Print user and group information for the each specified USER,\n\
or (when USER omitted) for the current user.\n\
\n"),
stdout);
@@ -116,18 +127,8 @@ main (int argc, char **argv)
int optc;
int selinux_enabled = (is_selinux_enabled () > 0);
bool smack_enabled = is_smack_enabled ();
- bool opt_zero = false;
char *pw_name = NULL;
- /* If true, output the list of all group IDs. -G */
- bool just_group_list = false;
- /* If true, output only the group ID(s). -g */
- bool just_group = false;
- /* If true, output real UID/GID instead of default effective UID/GID. -r */
- bool use_real = false;
- /* If true, output only the user ID(s). -u */
- bool just_user = false;
-
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
@@ -185,11 +186,6 @@ main (int argc, char **argv)
}
size_t n_ids = argc - optind;
- if (1 < n_ids)
- {
- error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
- usage (EXIT_FAILURE);
- }
if (n_ids && just_context)
die (EXIT_FAILURE, 0,
@@ -228,29 +224,44 @@ main (int argc, char **argv)
die (EXIT_FAILURE, 0, _("can't get process context"));
}
- if (n_ids == 1)
- {
- struct passwd *pwd = NULL;
- const char *spec = argv[optind];
- /* Disallow an empty spec here as parse_user_spec() doesn't
- give an error for that as it seems it's a valid way to
- specify a noop or "reset special bits" depending on the system. */
- if (*spec)
- {
- if (parse_user_spec (spec, &euid, NULL, NULL, NULL) == NULL)
- {
- /* parse_user_spec will only extract a numeric spec,
- so we lookup that here to verify and also retrieve
- the PW_NAME used subsequently in group lookup. */
- pwd = getpwuid (euid);
- }
- }
- if (pwd == NULL)
- die (EXIT_FAILURE, 0, _("%s: no such user"), quote (spec));
- pw_name = xstrdup (pwd->pw_name);
- ruid = euid = pwd->pw_uid;
- rgid = egid = pwd->pw_gid;
- }
+ if (n_ids >= 1)
+ {
+ multiple_users = n_ids > 1 ? true : false;
+ /* Changing the value of n_ids to the last index in the array where we
+ have the last possible user id. This helps us because we don't have
+ to declare a different variable to keep a track of where the last username
+ lies in argv[]. */
+ n_ids += optind;
+ /* For each username/userid to get its pw_name field */
+ for (; optind < n_ids; optind++)
+ {
+ struct passwd *pwd = NULL;
+ const char *spec = argv[optind];
+ /* Disallow an empty spec here as parse_user_spec() doesn't
+ give an error for that as it seems it's a valid way to
+ specify a noop or "reset special bits" depending on the system. */
+ if (*spec) {
+ if (parse_user_spec(spec, &euid, NULL, NULL, NULL) == NULL)
+ {
+ /* parse_user_spec will only extract a numeric spec,
+ so we lookup that here to verify and also retrieve
+ the PW_NAME used subsequently in group lookup. */
+ pwd = getpwuid(euid);
+ }
+ }
+ if (pwd == NULL)
+ {
+ error (0, errno, _("%s: no such user"), quote (argv[optind]));
+ ok &= false;
+ continue;
+ }
+ pw_name = xstrdup(pwd->pw_name);
+ ruid = euid = pwd->pw_uid;
+ rgid = egid = pwd->pw_gid;
+ print_stuff(pw_name);
+ IF_LINT (free (pw_name));
+ }
+ }
else
{
/* POSIX says identification functions (getuid, getgid, and
@@ -289,34 +300,10 @@ main (int argc, char **argv)
if (rgid == NO_GID && errno)
die (EXIT_FAILURE, errno, _("cannot get real GID"));
}
+ print_stuff(pw_name);
+ IF_LINT (free (pw_name));
}
- if (just_user)
- {
- print_user (use_real ? ruid : euid);
- }
- else if (just_group)
- {
- if (!print_group (use_real ? rgid : egid, use_name))
- ok = false;
- }
- else if (just_group_list)
- {
- if (!print_group_list (pw_name, ruid, rgid, egid, use_name,
- opt_zero ? '\0' : ' '))
- ok = false;
- }
- else if (just_context)
- {
- fputs (context, stdout);
- }
- else
- {
- print_full_info (pw_name);
- }
- putchar (opt_zero ? '\0' : '\n');
-
- IF_LINT (free (pw_name));
return ok ? EXIT_SUCCESS : EXIT_FAILURE;
}
@@ -356,7 +343,7 @@ print_user (uid_t uid)
{
error (0, 0, _("cannot find name for user ID %s"),
uidtostr (uid));
- ok = false;
+ ok &= false;
}
}
@@ -415,7 +402,7 @@ print_full_info (const char *username)
quote (username));
else
error (0, errno, _("failed to get groups for the current process"));
- ok = false;
+ ok &= false;
return;
}
@@ -438,3 +425,37 @@ print_full_info (const char *username)
if (context)
printf (_(" context=%s"), context);
}
+
+/* Print information about the user based on the arguments passed. */
+
+static void
+print_stuff(const char *pw_name)
+{
+ if (just_user)
+ print_user (use_real ? ruid : euid);
+
+ /* print_group and print_group_lists functions return true on successful
+ execution but false if something goes wrong. We then AND this value with
+ the current value of 'ok' because we want to know if one of the previous
+ users faced a problem in these functions. This value of 'ok' is later used
+ to understand what status program should exit with. */
+ else if (just_group)
+ ok &= print_group (use_real ? rgid : egid, use_name);
+ else if (just_group_list)
+ ok &= print_group_list (pw_name, ruid, rgid, egid,
+ use_name, opt_zero ? '\0' : ' ');
+ else if (just_context)
+ fputs (context, stdout);
+ else
+ print_full_info (pw_name);
+ /* When printing records for more than 1 user, at the end of groups
+ of each user terminate the record with two consequent NUL characters
+ to make parsing and distinguishing between two records possible. */
+ if (opt_zero && just_group_list && multiple_users)
+ {
+ putchar('\0');
+ putchar('\0');
+ }
+ else
+ putchar (opt_zero ? '\0' : '\n');
+}
diff --git a/tests/id/zero.sh b/tests/id/zero.sh
index f183e18f8..7a94edde1 100755
--- a/tests/id/zero.sh
+++ b/tests/id/zero.sh
@@ -63,4 +63,38 @@ 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
+
+# Seperate checks when we are testing for multiple users && -G.
+# This is done because we terminate the records with two consequent
+# NULs instead of the regular single NUL.
+
+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
+ # consequent spaces instead of two consequent 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/ \+ /\n/g' >> gtmp3
+ done
+done
+compare gtmp1 gtmp3 || fail=1
+
Exit $fail
--
2.17.1

[Pádraig Brady]

Post by Achilles Gaikwad
Adds a feature to id command to accept multiple usernames and/or uid
as arguments.
$ id root nobody
uid=0(root) gid=0(root) groups=0(root)
uid=99(nobody) gid=99(nobody) groups=99(nobody)

Cool thanks.
The attached adjustments include the following:

- test case to ensure all users processed in the presence of errors
- test portability fixes with sed usage
- fix global variables to have static linkage
- fix a mem leak for pw_name
- Add (texinfo) docs on double NUL behavior
- adjust to GNU coding style
- Add NEWS entry
- spelling/grammar fixes

I'll squash and push later.

thanks!
Pádraig

[Achilles Gaikwad]

Thank you very much Pádraig! :)
Best,
- Achilles