lib/shadow.c: my_sgetspent(): There can be only one!

lib/shadow.c: my_sgetspent(): There can be only one!

We already have sgetspent(), with identical semantics, defined in
<lib/sgetspent.c>.

	$ diff -u <(grepc sgetspent .) <(grepc my_sgetspent .)
	--- /dev/fd/63	2024-11-11 11:56:55.444055921 +0100
	+++ /dev/fd/62	2024-11-11 11:56:55.444055921 +0100
	@@ -1,23 +1,19 @@
	-./lib/sgetspent.c:struct spwd *
	-sgetspent(const char *string)
	+./lib/shadow.c:static struct spwd *my_sgetspent (const char *string)
	 {
	-	static char spwbuf[PASSWD_ENTRY_MAX_LENGTH];
	-	static struct spwd spwd;
	-	char *fields[FIELDS];
	-	char *cp;
	-	int i;
	+	int                 i;
	+	char                *fields[FIELDS];
	+	char                *cp;
	+	static char         spwbuf[BUFSIZ];
	+	static char         empty[] = "";
	+	static struct spwd  spwd;

		/*
		 * Copy string to local buffer.  It has to be tokenized and we
		 * have to do that to our private copy.
		 */

	-	if (strlen (string) >= sizeof spwbuf) {
	-		fprintf (shadow_logfd,
	-		         "%s: Too long passwd entry encountered, file corruption?\n",
	-		         shadow_progname);
	-		return NULL;	/* fail if too long */
	-	}
	+	if (strlen (string) >= sizeof spwbuf)
	+		return 0;
		strcpy (spwbuf, string);
		stpsep(spwbuf, "\n");

	@@ -30,14 +26,16 @@
			fields[i] = strsep(&cp, ":");

		if (i == (FIELDS - 1))
	-		fields[i++] = "";
	+		fields[i++] = empty;

		if (cp != NULL || (i != FIELDS && i != OFIELDS))
	-		return NULL;
	+		return 0;

		/*
		 * Start populating the structure.  The fields are all in
	-	 * static storage, as is the structure we pass back.
	+	 * static storage, as is the structure we pass back.  If we
	+	 * ever see a name with '+' as the first character, we try
	+	 * to turn on NIS processing.
		 */

		spwd.sp_namp = fields[0];
	@@ -46,13 +44,13 @@
		/*
		 * Get the last changed date.  For all of the integer fields,
		 * we check for proper format.  It is an error to have an
	-	 * incorrectly formatted number.
	+	 * incorrectly formatted number, unless we are using NIS.
		 */

		if (fields[2][0] == '\0')
			spwd.sp_lstchg = -1;
		else if (a2sl(&spwd.sp_lstchg, fields[2], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * Get the minimum period between password changes.
	@@ -61,7 +59,7 @@
		if (fields[3][0] == '\0')
			spwd.sp_min = -1;
		else if (a2sl(&spwd.sp_min, fields[3], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * Get the maximum number of days a password is valid.
	@@ -70,7 +68,7 @@
		if (fields[4][0] == '\0')
			spwd.sp_max = -1;
		else if (a2sl(&spwd.sp_max, fields[4], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * If there are only OFIELDS fields (this is a SVR3.2 /etc/shadow
	@@ -93,7 +91,7 @@
		if (fields[5][0] == '\0')
			spwd.sp_warn = -1;
		else if (a2sl(&spwd.sp_warn, fields[5], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * Get the number of days of inactivity before an account is
	@@ -103,7 +101,7 @@
		if (fields[6][0] == '\0')
			spwd.sp_inact = -1;
		else if (a2sl(&spwd.sp_inact, fields[6], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * Get the number of days after the epoch before the account is
	@@ -113,7 +111,7 @@
		if (fields[7][0] == '\0')
			spwd.sp_expire = -1;
		else if (a2sl(&spwd.sp_expire, fields[7], NULL, 0, 0, LONG_MAX) == -1)
	-		return NULL;
	+		return 0;

		/*
		 * This field is reserved for future use.  But it isn't supposed
	@@ -123,8 +121,7 @@
		if (fields[8][0] == '\0')
			spwd.sp_flag = SHADOW_SP_FLAG_UNSET;
		else if (str2ul(&spwd.sp_flag, fields[8]) == -1)
	-		return NULL;
	+		return 0;

		return (&spwd);
	 }
	-./lib/prototypes.h:extern struct spwd *sgetspent (const char *string);

Closes: <https://github.com/shadow-maint/shadow/issues/1114>
Link: <https://www.youtube.com/watch?v=IpbvtSQvgWM>
Signed-off-by: Alejandro Colomar <alx@kernel.org>