lib/, src/: Use streq() instead of its pattern

Except for the added (and sorted) includes, the removal of redundant
parentheses, a few cases that have been refactored for readability, and
a couple of non-string cases that I've left out of the change, this
patch can be approximated with the following semantic patch:

	$ cat ~/tmp/spatch/streq.sp
	@@
	expression s;
	@@

	- '\0' == *s
	+ streq(s, "")

	@@
	expression s;
	@@

	- '\0' == s[0]
	+ streq(s, "")

	@@
	expression s;
	@@

	- *s == '\0'
	+ streq(s, "")

	@@
	expression s;
	@@

	- s[0] == '\0'
	+ streq(s, "")

	$ find contrib/ lib* src/ -type f \
	| xargs spatch --in-place --sp-file ~/tmp/spatch/streq.sp;

Signed-off-by: Alejandro Colomar <alx@kernel.org>

src/grpck.c

@@ -580,7 +580,8 @@ static void check_grp_file (int *errors, bool *changed)
 		 */
 		if (   (NULL != grp->gr_mem[0])
 		    && (NULL == grp->gr_mem[1])
-		    && ('\0' == grp->gr_mem[0][0])) {
+		    && streq(grp->gr_mem[0], ""))
+		{
 			grp->gr_mem[0] = NULL;
 		}
 

src/login.c

@@ -661,7 +661,7 @@ int main (int argc, char **argv)
 		/* if we didn't get a user on the command line,
 		   set it to NULL */
 		get_pam_user (&pam_user);
-		if ((NULL != pam_user) && ('\0' == pam_user[0])) {
+		if ((NULL != pam_user) && streq(pam_user, "")) {
 			retcode = pam_set_item (pamh, PAM_USER, NULL);
 			PAM_FAIL_CHECK;
 		}
@@ -838,7 +838,7 @@ int main (int argc, char **argv)
 			username = XMALLOC(max_size, char);
 			login_prompt(username, max_size);
 
-			if ('\0' == username[0]) {
+			if (streq(username, "")) {
 				/* Prompt for a new login */
 				free (username);
 				username = NULL;
@@ -963,7 +963,7 @@ int main (int argc, char **argv)
 		 * guys won't see that the passwordless account exists at
 		 * all).  --marekm
 		 */
-		if (user_passwd[0] == '\0') {
+		if (streq(user_passwd, "")) {
 			pw_auth ("!", username, reason, NULL);
 		}
 

src/login_nopam.c

@@ -29,7 +29,6 @@
 #ifndef USE_PAM
 #ident "$Id$"
 
-#include "prototypes.h"
     /*
      * This module implements a simple but effective form of login access
      * control based on login names and on host (or domain) names, internet
@@ -38,27 +37,29 @@
      *
      * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
      */
-#include <sys/types.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <syslog.h>
+#include <arpa/inet.h>		/* for inet_ntoa() */
 #include <ctype.h>
-#include <netdb.h>
+#include <errno.h>
 #include <grp.h>
+#include <netdb.h>
+#include <netinet/in.h>
 #ifdef PRIMARY_GROUP_MATCH
 #include <pwd.h>
 #endif
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
+#include <stddef.h>
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/param.h>
 #include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>		/* for inet_ntoa() */
+#include <sys/types.h>
+#include <syslog.h>
+#include <unistd.h>
 
+#include "prototypes.h"
 #include "sizeof.h"
 #include "string/strchr/strrspn.h"
+#include "string/strcmp/streq.h"
 #include "string/strtok/stpsep.h"
 
 
@@ -110,7 +111,7 @@ login_access(const char *user, const char *from)
 				continue;	/* comment line */
 			}
 			stpcpy(strrspn(line, " \t"), "");
-			if (line[0] == '\0') {	/* skip blank lines */
+			if (streq(line, "")) {	/* skip blank lines */
 				continue;
 			}
 			p = line;
@@ -182,7 +183,7 @@ static char *myhostname (void)
 {
 	static char name[MAXHOSTNAMELEN + 1] = "";
 
-	if (name[0] == '\0') {
+	if (streq(name, "")) {
 		gethostname (name, sizeof (name));
 		stpcpy(&name[MAXHOSTNAMELEN], "");
 	}

src/newgrp.c

@@ -150,7 +150,7 @@ static void check_perms (const struct group *grp,
 		spw_free (spwd);
 	}
 
-	if ((pwd->pw_passwd[0] == '\0') && (grp->gr_passwd[0] != '\0')) {
+	if (streq(pwd->pw_passwd, "") && (grp->gr_passwd[0] != '\0')) {
 		needspasswd = true;
 	}
 
@@ -188,8 +188,8 @@ static void check_perms (const struct group *grp,
 			goto failure;
 		}
 
-		if (grp->gr_passwd[0] == '\0' ||
-		    !streq(cpasswd, grp->gr_passwd)) {
+		if (streq(grp->gr_passwd, "") ||
+		    !streq(grp->gr_passwd, cpasswd)) {
 #ifdef WITH_AUDIT
 			SNPRINTF(audit_buf, "authentication new-gid=%lu",
 			         (unsigned long) grp->gr_gid);

src/passwd.c

@@ -441,7 +441,7 @@ static /*@observer@*/const char *pw_status (const char *pass)
 	if (*pass == '*' || *pass == '!') {
 		return "L";
 	}
-	if (*pass == '\0') {
+	if (streq(pass, "")) {
 		return "NP";
 	}
 	return "P";

src/su.c

@@ -862,7 +862,7 @@ static void process_flags (int argc, char **argv)
 	if (optind < argc) {
 		STRTCPY(name, argv[optind++]);	/* use this login id */
 	}
-	if ('\0' == name[0]) {		/* use default user */
+	if (streq(name, "")) {		/* use default user */
 		struct passwd *root_pw = getpwnam ("root");
 		if ((NULL != root_pw) && (0 == root_pw->pw_uid)) {
 			(void) strcpy (name, "root");
@@ -1080,7 +1080,7 @@ int main (int argc, char **argv)
 	/*
 	 * Set the default shell.
 	 */
-	if ((NULL == shellstr) || ('\0' == shellstr[0])) {
+	if ((NULL == shellstr) || streq(shellstr, "")) {
 		shellstr = SHELL;
 	}
 

src/suauth.c

@@ -86,7 +86,7 @@ check_su_auth(const char *actual_id, const char *wanted_id, bool su_to_root)
 		stpcpy(strrspn(temp, " \t"), "");
 
 		p = stpspn(temp, " \t");
-		if (*p == '#' || *p == '\0')
+		if (*p == '#' || streq(p, ""))
 			continue;
 
 		to_users = strsep(&p, ":");

src/sulogin.c

@@ -27,6 +27,7 @@
 /*@-exitarg@*/
 #include "exitcodes.h"
 #include "shadowlog.h"
+#include "string/strcmp/streq.h"
 #include "string/strdup/xstrdup.h"
 
 
@@ -153,7 +154,7 @@ main(int argc, char *argv[])
 		 * it will work with standard getpass() (no NULL on EOF).
 		 * --marekm
 		 */
-		if ((NULL == pass) || ('\0' == *pass)) {
+		if ((NULL == pass) || streq(pass, "")) {
 			erase_pass (pass);
 			(void) puts ("");
 #ifdef	TELINIT

src/useradd.c

@@ -439,7 +439,7 @@ get_defaults(void)
 		 * Default Skeleton information
 		 */
 		else if (streq(buf, DSKEL)) {
-			if ('\0' == *ccp)
+			if (streq(ccp, ""))
 				ccp = SKEL_DIR;
 
 			if (prefix[0]) {
@@ -456,7 +456,7 @@ get_defaults(void)
 		 * Default Usr Skeleton information
 		 */
 		else if (streq(buf, DUSRSKEL)) {
-			if ('\0' == *ccp)
+			if (streq(ccp, ""))
 				ccp = USRSKELDIR;
 
 			if (prefix[0]) {
@@ -472,7 +472,7 @@ get_defaults(void)
 		 * Create by default user mail spool or not ?
 		 */
 		else if (streq(buf, DCREATE_MAIL_SPOOL)) {
-			if (*ccp == '\0')
+			if (streq(ccp, ""))
 				ccp = "no";
 
 			def_create_mail_spool = xstrdup(ccp);
@@ -482,7 +482,7 @@ get_defaults(void)
 		 * By default do we add the user to the lastlog and faillog databases ?
 		 */
 		else if (streq(buf, DLOG_INIT)) {
-			if (*ccp == '\0')
+			if (streq(ccp, ""))
 				ccp = def_log_init;
 
 			def_log_init = xstrdup(ccp);
@@ -770,7 +770,7 @@ static int get_groups (char *list)
 		user_groups[i++] = NULL;
 	}
 
-	if ('\0' == *list) {
+	if (streq(list, "")) {
 		return 0;
 	}
 

src/userdel.c

@@ -1131,7 +1131,7 @@ int main (int argc, char **argv)
 	 * Note: This is a best effort basis. The user may log in between,
 	 * a cron job may be started on her behalf, etc.
 	 */
-	if ((prefix[0] == '\0') && !Rflg && user_busy (user_name, user_id) != 0) {
+	if (streq(prefix, "") && !Rflg && user_busy(user_name, user_id) != 0) {
 		if (!fflg) {
 #ifdef WITH_AUDIT
 			audit_logger (AUDIT_DEL_USER, Prog,
@@ -1264,7 +1264,7 @@ int main (int argc, char **argv)
 	 * Cancel any crontabs or at jobs. Have to do this before we remove
 	 * the entry from /etc/passwd.
 	 */
-	if (prefix[0] == '\0')
+	if (streq(prefix, ""))
 		user_cancel (user_name);
 	close_files ();
 

src/usermod.c

@@ -227,7 +227,7 @@ static int get_groups (char *list)
 	 */
 	user_groups[0] = NULL;
 
-	if ('\0' == *list) {
+	if (streq(list, "")) {
 		return 0;
 	}
 
@@ -2186,7 +2186,7 @@ int main (int argc, char **argv)
 	 * be changed while the user is logged in.
 	 * Note: no need to check if a prefix is specified...
 	 */
-	if ( (prefix[0] == '\0') &&  (uflg || lflg || dflg
+	if (streq(prefix, "") && (uflg || lflg || dflg
 #ifdef ENABLE_SUBIDS
 	        || Vflg || Wflg
 #endif				/* ENABLE_SUBIDS */