refactor passwd file access code

this allows getpwnam and getpwuid to share code with the _r versions
in preparation for alternate backend support.

src/passwd/fgetpwent.c

@@ -6,5 +6,7 @@ struct passwd *fgetpwent(FILE *f)
 	static char *line;
 	static struct passwd pw;
 	size_t size=0;
-	return __getpwent_a(f, &pw, &line, &size);
+	struct passwd *res;
+	__getpwent_a(f, &pw, &line, &size, &res);
+	return res;
 }

src/passwd/getpw_a.c

@@ -0,0 +1,31 @@
+#include "pwf.h"
+#include <pthread.h>
+
+int __getpw_a(const char *name, uid_t uid, struct passwd *pw, char **buf, size_t *size, struct passwd **res)
+{
+	FILE *f;
+	int cs;
+	int rv = 0;
+
+	*res = 0;
+
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
+	f = fopen("/etc/passwd", "rbe");
+	if (!f) {
+		rv = errno;
+		goto done;
+	}
+
+	while (!(rv = __getpwent_a(f, pw, buf, size, res)) && *res) {
+		if (name && !strcmp(name, (*res)->pw_name)
+		|| !name && (*res)->pw_uid == uid)
+			break;
+	}
+	fclose(f);
+
+done:
+	pthread_setcancelstate(cs, 0);
+	if (rv) errno = rv;
+	return rv;
+}

src/passwd/getpw_r.c

@@ -5,7 +5,6 @@
 
 static int getpw_r(const char *name, uid_t uid, struct passwd *pw, char *buf, size_t size, struct passwd **res)
 {
-	FILE *f;
 	char *line = 0;
 	size_t len = 0;
 	int rv = 0;
@@ -13,33 +12,20 @@ static int getpw_r(const char *name, uid_t uid, struct passwd *pw, char *buf, si
 
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 
-	f = fopen("/etc/passwd", "rbe");
-	if (!f) {
-		rv = errno;
-		goto done;
+	rv = __getpw_a(name, uid, pw, &line, &len, res);
+	if (!rv && size < len) {
+		*res = 0;
+		rv = ERANGE;
 	}
-
-	*res = 0;
-	while (__getpwent_a(f, pw, &line, &len)) {
-		if (name && !strcmp(name, pw->pw_name)
-		|| !name && pw->pw_uid == uid) {
-			if (size < len) {
-				rv = ERANGE;
-				break;
-			}
-			*res = pw;
-			memcpy(buf, line, len);
-			FIX(name);
-			FIX(passwd);
-			FIX(gecos);
-			FIX(dir);
-			FIX(shell);
-			break;
-		}
+	if (!rv) {
+		memcpy(buf, line, len);
+		FIX(name);
+		FIX(passwd);
+		FIX(gecos);
+		FIX(dir);
+		FIX(shell);
 	}
  	free(line);
-	fclose(f);
-done:
 	pthread_setcancelstate(cs, 0);
 	return rv;
 }

src/passwd/getpwent.c

@@ -1,6 +1,9 @@
 #include "pwf.h"
 
 static FILE *f;
+static char *line;
+static struct passwd pw;
+static size_t size;
 
 void setpwent()
 {
@@ -12,34 +15,23 @@ weak_alias(setpwent, endpwent);
 
 struct passwd *getpwent()
 {
-	static char *line;
-	static struct passwd pw;
-	size_t size=0;
+	struct passwd *res;
 	if (!f) f = fopen("/etc/passwd", "rbe");
 	if (!f) return 0;
-	return __getpwent_a(f, &pw, &line, &size);
+	__getpwent_a(f, &pw, &line, &size, &res);
+	return res;
 }
 
 struct passwd *getpwuid(uid_t uid)
 {
-	struct passwd *pw;
-	int errno_saved;
-	setpwent();
-	while ((pw=getpwent()) && pw->pw_uid != uid);
-	errno_saved = errno;
-	endpwent();
-	errno = errno_saved;
-	return pw;
+	struct passwd *res;
+	__getpw_a(0, uid, &pw, &line, &size, &res);
+	return res;
 }
 
 struct passwd *getpwnam(const char *name)
 {
-	struct passwd *pw;
-	int errno_saved;
-	setpwent();
-	while ((pw=getpwent()) && strcmp(pw->pw_name, name));
-	errno_saved = errno;
-	endpwent();
-	errno = errno_saved;
-	return pw;
+	struct passwd *res;
+	__getpw_a(name, 0, &pw, &line, &size, &res);
+	return res;
 }

src/passwd/getpwent_a.c

@@ -8,14 +8,16 @@ static unsigned atou(char **s)
 	return x;
 }
 
-struct passwd *__getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *size)
+int __getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *size, struct passwd **res)
 {
 	ssize_t l;
 	char *s;
+	int rv = 0;
 	int cs;
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 	for (;;) {
 		if ((l=getline(line, size, f)) < 0) {
+			rv = errno;
 			free(*line);
 			*line = 0;
 			pw = 0;
@@ -46,5 +48,7 @@ struct passwd *__getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *siz
 		break;
 	}
 	pthread_setcancelstate(cs, 0);
-	return pw;
+	*res = pw;
+	if (rv) errno = rv;
+	return rv;
 }

src/passwd/pwf.h

@@ -8,6 +8,7 @@
 #include <limits.h>
 #include "libc.h"
 
-struct passwd *__getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *size);
+int __getpwent_a(FILE *f, struct passwd *pw, char **line, size_t *size, struct passwd **res);
+int __getpw_a(const char *name, uid_t uid, struct passwd *pw, char **buf, size_t *size, struct passwd **res);
 struct group *__getgrent_a(FILE *f, struct group *gr, char **line, size_t *size, char ***mem, size_t *nmem);
 int __parsespent(char *s, struct spwd *sp);