Add fgets_a(), and use it instead of its pattern

lib/Makefile.am

@@ -186,6 +186,8 @@ libshadow_la_SOURCES = \
 	spawn.c \
 	sssd.c \
 	sssd.h \
+	io/fgets/fgets.c \
+	io/fgets/fgets.h \
 	string/ctype/strchrisascii/strchriscntrl.c \
 	string/ctype/strchrisascii/strchriscntrl.h \
 	string/ctype/strisascii/strisdigit.c \

lib/console.c

@@ -15,6 +15,7 @@
 
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/strcmp/streq.h"
 #include "string/strcmp/strprefix.h"
@@ -76,7 +77,7 @@ is_listed(const char *cfgin, const char *tty, bool def)
 	 * See if this tty is listed in the console file.
 	 */
 
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while (fgets_a(buf, fp) != NULL) {
 		stpsep(buf, "\n");
 		if (streq(buf, tty)) {
 			(void) fclose (fp);

lib/fields.c

@@ -15,7 +15,9 @@
 #include <stddef.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/param.h>
 
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/ctype/strisascii/strisprint.h"
 #include "string/ctype/strchrisascii/strchriscntrl.h"
@@ -60,16 +62,12 @@ valid_field_(const char *field, const char *illegal)
 void
 change_field(char *buf, size_t maxsize, const char *prompt)
 {
-	char newf[200];
 	char *cp;
-
-	if (maxsize > sizeof(newf)) {
-		maxsize = sizeof(newf);
-	}
+	char  newf[MIN(200, maxsize)];
 
 	printf ("\t%s [%s]: ", prompt, buf);
 	(void) fflush (stdout);
-	if (fgets(newf, maxsize, stdin) == NULL)
+	if (fgets_a(newf, stdin) == NULL)
 		return;
 
 	if (stpsep(newf, "\n") == NULL)

lib/getdef.c

@@ -25,6 +25,7 @@
 #include "atoi/a2i.h"
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "shadowlog_internal.h"
 #include "sizeof.h"
@@ -553,7 +554,7 @@ static void def_load (void)
 	/*
 	 * Go through all of the lines in the file.
 	 */
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while (fgets_a(buf, fp) != NULL) {
 
 		/*
 		 * Trim trailing whitespace.

lib/hushed.c

@@ -20,6 +20,7 @@
 
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/sprintf/snprintf.h"
 #include "string/strcmp/streq.h"
@@ -74,7 +75,7 @@ bool hushed (const char *username)
 	if (NULL == fp) {
 		return false;
 	}
-	for (found = false; !found && (fgets(buf, sizeof(buf), fp) != NULL);) {
+	for (found = false; !found && (fgets_a(buf, fp) != NULL);) {
 		stpsep(buf, "\n");
 		found = streq(buf, pw->pw_shell) ||
 		        streq(buf, pw->pw_name);

lib/io/fgets/fgets.c

@@ -0,0 +1,7 @@
+// SPDX-FileCopyrightText: 2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#include "config.h"
+
+#include "io/fgets/fgets.h"

lib/io/fgets/fgets.h

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: 2024-2025, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#ifndef SHADOW_INCLUDE_LIB_IO_FGETS_FGETS_H_
+#define SHADOW_INCLUDE_LIB_IO_FGETS_FGETS_H_
+
+
+#include "config.h"
+
+#include <stdio.h>
+
+#include "sizeof.h"
+
+
+// fgets_a - FILE get string array-safe
+#define fgets_a(buf, stream)  fgets(buf, countof(buf), stream)
+
+
+#endif  // include guard

lib/limits.c

@@ -31,6 +31,7 @@
 #include <sys/resource.h>
 
 #include "atoi/a2i.h"
+#include "io/fgets/fgets.h"
 #include "string/memset/memzero.h"
 #include "string/strcmp/streq.h"
 #include "string/strcmp/strprefix.h"
@@ -366,7 +367,7 @@ static int setup_user_limits (const char *uname)
 	 *
 	 * FIXME: a better (smarter) checking should be done
 	 */
-	while (fgets (buf, 1024, fil) != NULL) {
+	while (fgets_a(buf, fil) != NULL) {
 		if (strprefix(buf, "#") || strprefix(buf, "\n")) {
 			continue;
 		}

lib/loginprompt.c

@@ -19,6 +19,7 @@
 #include "attr.h"
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/memset/memzero.h"
 #include "string/strcpy/strtcpy.h"
@@ -85,7 +86,7 @@ login_prompt(char *name, int namesize)
 	 */
 
 	memzero_a(buf);
-	if (fgets(buf, sizeof(buf), stdin) == NULL)
+	if (fgets_a(buf, stdin) == NULL)
 		exit (EXIT_FAILURE);
 
 	if (stpsep(buf, "\n") == NULL)

lib/port.c

@@ -17,6 +17,7 @@
 #include <string.h>
 
 #include "defines.h"
+#include "io/fgets/fgets.h"
 #include "port.h"
 #include "prototypes.h"
 #include "string/strcmp/streq.h"
@@ -139,7 +140,7 @@ getportent(void)
 	 */
 
 next:
-	if (fgets(buf, sizeof(buf), ports) == NULL) {
+	if (fgets_a(buf, ports) == NULL) {
 		errno = saveerr;
 		return NULL;
 	}

lib/setupenv.c

@@ -15,17 +15,17 @@
 
 #ident "$Id$"
 
-#include <assert.h>
+#include <ctype.h>
+#include <pwd.h>
 #include <stddef.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <stdio.h>
-#include <ctype.h>
 
 #include "prototypes.h"
 #include "defines.h"
-#include <pwd.h>
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "shadowlog.h"
 #include "string/sprintf/aprintf.h"
 #include "string/strcmp/streq.h"
@@ -34,6 +34,8 @@
 #include "string/strspn/stpspn.h"
 #include "string/strtok/stpsep.h"
 
+#include <assert.h>
+
 
 #ifndef USE_PAM
 static void
@@ -56,7 +58,7 @@ static void read_env_file (const char *filename)
 	if (NULL == fp) {
 		return;
 	}
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while (fgets_a(buf, fp) != NULL) {
 		if (stpsep(buf, "\n") == NULL)
 			break;
 

lib/ttytype.c

@@ -17,6 +17,7 @@
 
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/strcmp/streq.h"
 #include "string/strcmp/strprefix.h"
@@ -48,7 +49,7 @@ void ttytype (const char *line)
 			perror (typefile);
 		return;
 	}
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while (fgets_a(buf, fp) != NULL) {
 		if (strprefix(buf, "#")) {
 			continue;
 		}

lib/tz.c

@@ -19,6 +19,7 @@
 
 #include "defines.h"
 #include "getdef.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/strtok/stpsep.h"
 
@@ -37,7 +38,7 @@
 
 	fp = fopen (fname, "r");
 	if (   (NULL == fp)
-	    || (fgets(tzbuf, sizeof(tzbuf), fp) == NULL)) {
+	    || (fgets_a(tzbuf, fp) == NULL)) {
 		result = "TZ=CST6CDT";
 	} else {
 		stpsep(tzbuf, "\n");

lib/user_busy.c

@@ -23,6 +23,7 @@
 #include "atoi/getnum.h"
 #include "defines.h"
 #include "fs/readlink/readlinknul.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #ifdef ENABLE_SUBIDS
 #include "subordinateio.h"
@@ -128,7 +129,7 @@ static int check_status (const char *name, const char *sname, uid_t uid)
 	if (NULL == sfile) {
 		return 0;
 	}
-	while (fgets(line, sizeof(line), sfile) != NULL) {
+	while (fgets_a(line, sfile) != NULL) {
 		if (strprefix(line, "Uid:\t")) {
 			unsigned long ruid, euid, suid;
 

src/chgpasswd.c

@@ -34,6 +34,7 @@
 #endif
 /*@-exitarg@*/
 #include "exitcodes.h"
+#include "io/fgets/fgets.h"
 #include "shadow/gshadow/sgrp.h"
 #include "shadowlog.h"
 #include "string/strcmp/streq.h"
@@ -476,7 +477,7 @@ int main (int argc, char **argv)
 	 * group entry for each group will be looked up in the appropriate
 	 * file (gshadow or group) and the password changed.
 	 */
-	while (fgets(buf, sizeof(buf), stdin) != NULL) {
+	while (fgets_a(buf, stdin) != NULL) {
 		line++;
 		if (stpsep(buf, "\n") == NULL) {
 			fprintf (stderr, _("%s: line %jd: line too long\n"),

src/chpasswd.c

@@ -33,6 +33,7 @@
 #include "shadowio.h"
 /*@-exitarg@*/
 #include "exitcodes.h"
+#include "io/fgets/fgets.h"
 #include "shadowlog.h"
 #include "string/strcmp/streq.h"
 #include "string/strerrno.h"
@@ -522,14 +523,14 @@ int main (int argc, char **argv)
 	 * last change date is set in the age only if aging information is
 	 * present.
 	 */
-	while (fgets(buf, sizeof(buf), stdin) != NULL) {
+	while (fgets_a(buf, stdin) != NULL) {
 		char  *cp;
 
 		line++;
 		if (stpsep(buf, "\n") == NULL) {
 			if (feof (stdin) == 0) {
 				// Drop all remaining characters on this line.
-				while (fgets(buf, sizeof(buf), stdin) != NULL) {
+				while (fgets_a(buf, stdin) != NULL) {
 					if (strchr(buf, '\n'))
 						break;
 				}

src/login_nopam.c

@@ -58,6 +58,7 @@
 #include <unistd.h>
 
 #include "defines.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "sizeof.h"
 #include "string/strcmp/strcaseeq.h"
@@ -100,7 +101,7 @@ login_access(const char *user, const char *from)
 	if (NULL != fp) {
 		intmax_t lineno = 0;	/* for diagnostics */
 		while (   !match
-		       && (fgets(line, sizeof(line), fp) != NULL))
+		       && (fgets_a(line, fp) != NULL))
 		{
 			char  *p;
 

src/newusers.c

@@ -45,6 +45,7 @@
 #include "defines.h"
 #include "getdef.h"
 #include "groupio.h"
+#include "io/fgets/fgets.h"
 #include "nscd.h"
 #include "prototypes.h"
 #include "pwio.h"
@@ -1111,7 +1112,7 @@ int main (int argc, char **argv)
 	 * over 100 is allocated. The pw_gid field will be updated with that
 	 * value.
 	 */
-	while (fgets(buf, sizeof(buf), stdin) != NULL) {
+	while (fgets_a(buf, stdin) != NULL) {
 		line++;
 		if (stpsep(buf, "\n") == NULL && feof(stdin) == 0) {
 			fprintf (stderr, _("%s: line %jd: line too long\n"),

src/suauth.c

@@ -18,6 +18,7 @@
 #include <sys/types.h>
 
 #include "defines.h"
+#include "io/fgets/fgets.h"
 #include "prototypes.h"
 #include "string/strcmp/streq.h"
 #include "string/strcmp/strprefix.h"
@@ -73,7 +74,7 @@ check_su_auth(const char *actual_id, const char *wanted_id, bool su_to_root)
 		return DENY;
 	}
 
-	while (fgets(temp, sizeof(temp), authfile_fd) != NULL) {
+	while (fgets_a(temp, authfile_fd) != NULL) {
 		char  *p;
 
 		lines++;

src/useradd.c

@@ -47,6 +47,7 @@
 #include "fs/mkstemp/fmkomstemp.h"
 #include "getdef.h"
 #include "groupio.h"
+#include "io/fgets/fgets.h"
 #include "nscd.h"
 #include "prototypes.h"
 #include "pwauth.h"
@@ -356,7 +357,7 @@ get_defaults(const struct option_flags *flags)
 	 * Read the file a line at a time. Only the lines that have relevant
 	 * values are used, everything else can be ignored.
 	 */
-	while (fgets(buf, sizeof(buf), fp) != NULL) {
+	while (fgets_a(buf, fp) != NULL) {
 		stpsep(buf, "\n");
 
 		cp = stpsep(buf, "=");
@@ -588,7 +589,7 @@ set_defaults(void)
 		goto skip;
 	}
 
-	while (fgets(buf, sizeof(buf), ifp) != NULL) {
+	while (fgets_a(buf, ifp) != NULL) {
 		char  *val;
 
 		if (stpsep(buf, "\n") == NULL) {