diff --git a/lib/nss.c b/lib/nss.c
index af3e95ac..02742902 100644
--- a/lib/nss.c
+++ b/lib/nss.c
@@ -29,7 +29,7 @@ bool nss_is_initialized() {
 	return atomic_load(&nss_init_completed);
 }
 
-void nss_exit() {
+static void nss_exit(void) {
 	if (nss_is_initialized() && subid_nss) {
 		dlclose(subid_nss->handle);
 		free(subid_nss);
@@ -38,7 +38,7 @@ void nss_exit() {
 }
 
 // nsswitch_path is an argument only to support testing.
-void nss_init(char *nsswitch_path) {
+void nss_init(const char *nsswitch_path) {
 	FILE *nssfp = NULL;
 	char *line = NULL, *p, *token, *saveptr;
 	size_t len = 0;
diff --git a/lib/prototypes.h b/lib/prototypes.h
index 6f80df82..cd873bf7 100644
--- a/lib/prototypes.h
+++ b/lib/prototypes.h
@@ -164,7 +164,7 @@ extern int getrange (char *range,
                      unsigned long *max, bool *has_max);
 
 /* gettime.c */
-extern time_t gettime ();
+extern time_t gettime (void);
 
 /* get_uid.c */
 extern int get_uid (const char *uidstr, uid_t *uid);
@@ -242,8 +242,8 @@ extern /*@null@*//*@only@*/struct passwd *get_my_pwent (void);
 
 /* nss.c */
 #include <libsubid/subid.h>
-extern void nss_init(char *nsswitch_path);
-extern bool nss_is_initialized();
+extern void nss_init(const char *nsswitch_path);
+extern bool nss_is_initialized(void);
 
 struct subid_nss_ops {
 	/*
@@ -293,7 +293,7 @@ struct subid_nss_ops {
 	void *handle;
 };
 
-extern struct subid_nss_ops *get_subid_nss_handle();
+extern struct subid_nss_ops *get_subid_nss_handle(void);
 
 
 /* pam_pass_non_interactive.c */
@@ -324,12 +324,12 @@ extern struct passwd *prefix_getpwuid(uid_t uid);
 extern struct passwd *prefix_getpwnam(const char* name);
 extern struct spwd *prefix_getspnam(const char* name);
 extern struct group *prefix_getgr_nam_gid(const char *grname);
-extern void prefix_setpwent();
-extern struct passwd* prefix_getpwent();
-extern void prefix_endpwent();
-extern void prefix_setgrent();
-extern struct group* prefix_getgrent();
-extern void prefix_endgrent();
+extern void prefix_setpwent(void);
+extern struct passwd* prefix_getpwent(void);
+extern void prefix_endpwent(void);
+extern void prefix_setgrent(void);
+extern struct group* prefix_getgrent(void);
+extern void prefix_endgrent(void);
 
 /* pwd2spwd.c */
 #ifndef USE_PAM
diff --git a/lib/run_part.c b/lib/run_part.c
index 1ce06be0..1e4f154b 100644
--- a/lib/run_part.c
+++ b/lib/run_part.c
@@ -8,9 +8,10 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <lib/prototypes.h>
+#include "run_part.h"
 #include "shadowlog_internal.h"
 
-int run_part (char *script_path, char *name, char *action)
+int run_part (char *script_path, const char *name, const char *action)
 {
 	int pid;
 	int wait_status;
@@ -39,7 +40,7 @@ int run_part (char *script_path, char *name, char *action)
 	return (1);
 }
 
-int run_parts (char *directory, char *name, char *action)
+int run_parts (const char *directory, const char *name, const char *action)
 {
 	struct dirent **namelist;
 	int scanlist;
@@ -47,7 +48,7 @@ int run_parts (char *directory, char *name, char *action)
 	int execute_result;
 
 	scanlist = scandir (directory, &namelist, 0, alphasort);
-	if (scanlist<0) {
+	if (scanlist<=0) {
 		return (0);
 	}
 
diff --git a/lib/run_part.h b/lib/run_part.h
index d3d80663..0b68dbfc 100644
--- a/lib/run_part.h
+++ b/lib/run_part.h
@@ -1,2 +1,2 @@
-int run_part (char *script_path, char *name, char *action);
-int run_parts (char *directory, char *name, char *action);
+int run_part (char *script_path, const char *name, const char *action);
+int run_parts (const char *directory, const char *name, const char *action);
diff --git a/libmisc/idmapping.h b/libmisc/idmapping.h
index e3527606..81a628b8 100644
--- a/libmisc/idmapping.h
+++ b/libmisc/idmapping.h
@@ -17,7 +17,5 @@ extern struct map_range *get_map_ranges(int ranges, int argc, char **argv);
 extern void write_mapping(int proc_dir_fd, int ranges,
 	struct map_range *mappings, const char *map_file, uid_t ruid);
 
-extern void nss_init(char *nsswitch_path);
-
 #endif /* _ID_MAPPING_H_ */
 
diff --git a/libmisc/prefix_flag.c b/libmisc/prefix_flag.c
index d4dfbc20..4eb51547 100644
--- a/libmisc/prefix_flag.c
+++ b/libmisc/prefix_flag.c
@@ -248,7 +248,7 @@ extern struct spwd *prefix_getspnam(const char* name)
 	}
 }
 
-extern void prefix_setpwent()
+extern void prefix_setpwent(void)
 {
 	if (!passwd_db_file) {
 		setpwent();
@@ -261,7 +261,7 @@ extern void prefix_setpwent()
 	if (!fp_pwent)
 		return;
 }
-extern struct passwd* prefix_getpwent()
+extern struct passwd* prefix_getpwent(void)
 {
 	if (!passwd_db_file) {
 		return getpwent();
@@ -271,7 +271,7 @@ extern struct passwd* prefix_getpwent()
 	}
 	return fgetpwent(fp_pwent);
 }
-extern void prefix_endpwent()
+extern void prefix_endpwent(void)
 {
 	if (!passwd_db_file) {
 		endpwent();
@@ -282,7 +282,7 @@ extern void prefix_endpwent()
 	fp_pwent = NULL;
 }
 
-extern void prefix_setgrent()
+extern void prefix_setgrent(void)
 {
 	if (!group_db_file) {
 		setgrent();
@@ -295,14 +295,14 @@ extern void prefix_setgrent()
 	if (!fp_grent)
 		return;
 }
-extern struct group* prefix_getgrent()
+extern struct group* prefix_getgrent(void)
 {
 	if (!group_db_file) {
 		return getgrent();
 	}
 	return fgetgrent(fp_grent);
 }
-extern void prefix_endgrent()
+extern void prefix_endgrent(void)
 {
 	if (!group_db_file) {
 		endgrent();
diff --git a/libmisc/shell.c b/libmisc/shell.c
index 29724063..7c67500d 100644
--- a/libmisc/shell.c
+++ b/libmisc/shell.c
@@ -45,7 +45,7 @@ int shell (const char *file, /*@null@*/const char *arg, char *const envp[])
 	 * don't want to tell us what it is themselves.
 	 */
 	if (arg == (char *) 0) {
-		(void) snprintf (arg0, sizeof arg0, "-%s", Basename ((char *) file));
+		(void) snprintf (arg0, sizeof arg0, "-%s", Basename (file));
 		arg0[sizeof arg0 - 1] = '\0';
 		arg = arg0;
 	}
diff --git a/src/free_subid_range.c b/src/free_subid_range.c
index a2d2e8e0..d9a2cd8d 100644
--- a/src/free_subid_range.c
+++ b/src/free_subid_range.c
@@ -11,7 +11,7 @@
 
 const char *Prog;
 
-void usage(void)
+static void usage(void)
 {
 	fprintf(stderr, "Usage: %s [-g] user start count\n", Prog);
 	fprintf(stderr, "    Release a user's subuid (or with -g, subgid) range\n");
diff --git a/src/get_subid_owners.c b/src/get_subid_owners.c
index b0f46397..36974b84 100644
--- a/src/get_subid_owners.c
+++ b/src/get_subid_owners.c
@@ -8,7 +8,7 @@
 
 const char *Prog;
 
-void usage(void)
+static void usage(void)
 {
 	fprintf(stderr, "Usage: [-g] %s subuid\n", Prog);
 	fprintf(stderr, "    list uids who own the given subuid\n");
diff --git a/src/getsubids.c b/src/getsubids.c
index 4384cfae..c91ae39e 100644
--- a/src/getsubids.c
+++ b/src/getsubids.c
@@ -9,7 +9,7 @@
 
 const char *Prog;
 
-void usage(void)
+static void usage(void)
 {
 	fprintf(stderr, "Usage: %s [-g] user\n", Prog);
 	fprintf(stderr, "    list subuid ranges for user\n");
diff --git a/src/grpck.c b/src/grpck.c
index 7accac94..881fb4de 100644
--- a/src/grpck.c
+++ b/src/grpck.c
@@ -455,7 +455,7 @@ static void check_grp_file (int *errors, bool *changed)
 	struct commonio_entry *gre, *tgre;
 	struct group *grp;
 #ifdef SHADOWGRP
-	struct sgrp *sgr;
+	const struct sgrp *sgr;
 #endif
 
 	/*
@@ -596,7 +596,7 @@ static void check_grp_file (int *errors, bool *changed)
 		 */
 
 		if (is_shadow) {
-			sgr = (struct sgrp *) sgr_locate (grp->gr_name);
+			sgr = sgr_locate (grp->gr_name);
 			if (sgr == NULL) {
 				printf (_("no matching group file entry in %s\n"),
 				        sgr_file);
@@ -663,7 +663,7 @@ static void check_grp_file (int *errors, bool *changed)
  */
 static void check_sgr_file (int *errors, bool *changed)
 {
-	struct group *grp;
+	const struct group *grp;
 	struct commonio_entry *sge, *tsge;
 	struct sgrp *sgr;
 
@@ -758,7 +758,7 @@ static void check_sgr_file (int *errors, bool *changed)
 		/*
 		 * Make sure this entry exists in the /etc/group file.
 		 */
-		grp = (struct group *) gr_locate (sgr->sg_name);
+		grp = gr_locate (sgr->sg_name);
 		if (grp == NULL) {
 			printf (_("no matching group file entry in %s\n"),
 			        grp_file);
diff --git a/src/new_subid_range.c b/src/new_subid_range.c
index 6cb294d4..523d480a 100644
--- a/src/new_subid_range.c
+++ b/src/new_subid_range.c
@@ -11,7 +11,7 @@
 
 const char *Prog;
 
-void usage(void)
+static void usage(void)
 {
 	fprintf(stderr, "Usage: %s [-g] [-n] user count\n", Prog);
 	fprintf(stderr, "    Find a subuid (or with -g, subgid) range for user\n");
diff --git a/src/newgidmap.c b/src/newgidmap.c
index ebf16cde..5b42431b 100644
--- a/src/newgidmap.c
+++ b/src/newgidmap.c
@@ -73,10 +73,11 @@ static void usage(void)
 	exit(EXIT_FAILURE);
 }
 
-void write_setgroups(int proc_dir_fd, bool allow_setgroups)
+static void write_setgroups(int proc_dir_fd, bool allow_setgroups)
 {
 	int setgroups_fd;
-	char *policy, policy_buffer[4096];
+	const char *policy;
+	char policy_buffer[4096];
 
 	/*
 	 * Default is "deny", and any "allow" will out-rank a "deny". We don't
diff --git a/src/newgrp.c b/src/newgrp.c
index cb88f6d7..99820832 100644
--- a/src/newgrp.c
+++ b/src/newgrp.c
@@ -379,7 +379,7 @@ int main (int argc, char **argv)
 	int err = 0;
 	gid_t gid;
 	char *cp;
-	char *progbase;
+	const char *progbase;
 	const char *name, *prog;
 	char *group = NULL;
 	char *command = NULL;
@@ -787,7 +787,7 @@ int main (int argc, char **argv)
 	 * Now I try to find the basename of the login shell. This will
 	 * become argv[0] of the spawned command.
 	 */
-	progbase = (char *) Basename ((char *) prog);
+	progbase = Basename (prog);
 
 	/*
 	 * Switch back to her home directory if i am doing login
diff --git a/src/newuidmap.c b/src/newuidmap.c
index 9aa2ddcc..546856a2 100644
--- a/src/newuidmap.c
+++ b/src/newuidmap.c
@@ -62,7 +62,7 @@ static void verify_ranges(struct passwd *pw, int ranges,
 	}
 }
 
-void usage(void)
+static void usage(void)
 {
 	fprintf(stderr, _("usage: %s <pid> <uid> <loweruid> <count> [ <uid> <loweruid> <count> ] ... \n"), Prog);
 	exit(EXIT_FAILURE);
diff --git a/src/newusers.c b/src/newusers.c
index c1d29f83..8e7c620d 100644
--- a/src/newusers.c
+++ b/src/newusers.c
@@ -464,7 +464,9 @@ static int add_passwd (struct passwd *pwd, const char *password)
 {
 	const struct spwd *sp;
 	struct spwd spent;
+#ifndef USE_PAM
 	char *cp;
+#endif				/* !USE_PAM */
 
 #ifndef USE_PAM
 	void *crypt_arg = NULL;
@@ -607,9 +609,11 @@ static int add_passwd (struct passwd *pwd, const char *password)
 static void process_flags (int argc, char **argv)
 {
 	int c;
+#ifndef USE_PAM
 #if defined(USE_SHA_CRYPT) || defined(USE_BCRYPT) || defined(USE_YESCRYPT)
         int bad_s;
 #endif				/* USE_SHA_CRYPT || USE_BCRYPT || USE_YESCRYPT */
+#endif 				/* !USE_PAM */
 	static struct option long_options[] = {
 		{"badnames",     no_argument,       NULL, 'b'},
 #ifndef USE_PAM
diff --git a/src/pwck.c b/src/pwck.c
index ee1df500..28209131 100644
--- a/src/pwck.c
+++ b/src/pwck.c
@@ -366,7 +366,7 @@ static void check_pw_file (int *errors, bool *changed)
 {
 	struct commonio_entry *pfe, *tpfe;
 	struct passwd *pwd;
-	struct spwd *spw;
+	const struct spwd *spw;
 	uid_t min_sys_id = (uid_t) getdef_ulong ("SYS_UID_MIN", 101UL);
 	uid_t max_sys_id = (uid_t) getdef_ulong ("SYS_UID_MAX", 999UL);
 
@@ -584,7 +584,7 @@ static void check_pw_file (int *errors, bool *changed)
 				spw_opened = true;
 			}
 #endif				/* WITH_TCB */
-			spw = (struct spwd *) spw_locate (pwd->pw_name);
+			spw = spw_locate (pwd->pw_name);
 			if (NULL == spw) {
 				printf (_("no matching password file entry in %s\n"),
 				        spw_dbname ());
diff --git a/src/useradd.c b/src/useradd.c
index 456b9de5..34376fa5 100644
--- a/src/useradd.c
+++ b/src/useradd.c
@@ -2492,7 +2492,7 @@ int main (int argc, char **argv)
 	    (!user_id || (user_id <= uid_max && user_id >= uid_min));
 #endif				/* ENABLE_SUBIDS */
 
-	if (run_parts ("/etc/shadow-maint/useradd-pre.d", (char*)user_name,
+	if (run_parts ("/etc/shadow-maint/useradd-pre.d", user_name,
 			"useradd")) {
 		exit(1);
 	}
@@ -2715,7 +2715,7 @@ int main (int argc, char **argv)
 		create_mail ();
 	}
 
-	if (run_parts ("/etc/shadow-maint/useradd-post.d", (char*)user_name,
+	if (run_parts ("/etc/shadow-maint/useradd-post.d", user_name,
 			"useradd")) {
 		exit(1);
 	}