login: add xgetpwnam()

Signed-off-by: Karel Zak <kzak@redhat.com>

include/Makemodule.am

@@ -19,6 +19,7 @@ dist_noinst_HEADERS += \
 	include/fileutils.h \
 	include/idcache.h \
 	include/ismounted.h \
+	include/pwdutils.h \
 	include/linux_version.h \
 	include/list.h \
 	include/loopdev.h \

include/pwdutils.h

@@ -0,0 +1,10 @@
+#ifndef UTIL_LINUX_PWDUTILS_H
+#define UTIL_LINUX_PWDUTILS_H
+
+#include <sys/types.h>
+#include <pwd.h>
+
+extern struct passwd *xgetpwnam(const char *username, char **pwdbuf);
+
+#endif /* UTIL_LINUX_PWDUTILS_H */
+

lib/Makemodule.am

@@ -18,6 +18,7 @@ libcommon_la_SOURCES = \
 	lib/pager.c \
 	lib/parse-date.y \
 	lib/path.c \
+	lib/pwdutils.c \
 	lib/randutils.c \
 	lib/setproctitle.c \
 	lib/strutils.c \
@@ -74,6 +75,7 @@ check_PROGRAMS += \
 	test_colors \
 	test_fileutils \
 	test_ismounted \
+	test_pwdutils \
 	test_mangle \
 	test_randutils \
 	test_strutils \
@@ -149,3 +151,6 @@ test_canonicalize_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_CANONICALIZE
 
 test_timeutils_SOURCES = lib/timeutils.c lib/strutils.c
 test_timeutils_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_TIMEUTILS
+
+test_pwdutils_SOURCES = lib/pwdutils.c
+test_pwdutils_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM

lib/pwdutils.c

@@ -0,0 +1,64 @@
+#include <stdlib.h>
+
+#include "c.h"
+#include "pwdutils.h"
+#include "xalloc.h"
+
+/* Returns allocated passwd and allocated pwdbuf to store passwd strings
+ * fields. In case of error returns NULL and set errno, for unknown user set
+ * errno to EINVAL
+ */
+struct passwd *xgetpwnam(const char *username, char **pwdbuf)
+{
+	struct passwd *pwd = NULL, *res = NULL;
+	int rc;
+
+	if (!pwdbuf || !username)
+		return NULL;
+
+	*pwdbuf = xmalloc(UL_GETPW_BUFSIZ);
+	pwd = xcalloc(1, sizeof(struct passwd));
+
+	errno = 0;
+	rc = getpwnam_r(username, pwd, *pwdbuf, UL_GETPW_BUFSIZ, &res);
+	if (rc != 0) {
+		errno = rc;
+		goto failed;
+	}
+	if (!res) {
+		errno = EINVAL;
+		goto failed;
+	}
+	return pwd;
+failed:
+	free(pwd);
+	free(*pwdbuf);
+	return NULL;
+}
+
+
+#ifdef TEST_PROGRAM
+int main(int argc, char *argv[])
+{
+	char *pwdbuf = NULL;
+	struct passwd *pwd = NULL;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s <username>\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	pwd = xgetpwnam(argv[1], &pwdbuf);
+	if (!pwd)
+		err(EXIT_FAILURE, "failed to get %s pwd entry", argv[1]);
+
+	printf("Username: %s\n", pwd->pw_name);
+	printf("UID:      %d\n", pwd->pw_uid);
+	printf("HOME:     %s\n", pwd->pw_dir);
+	printf("GECO:     %s\n", pwd->pw_gecos);
+
+	free(pwd);
+	free(pwdbuf);
+	return EXIT_SUCCESS;
+}
+#endif /* TEST_PROGRAM */

login-utils/login.c

@@ -77,6 +77,7 @@
 #include "all-io.h"
 #include "fileutils.h"
 #include "ttyutils.h"
+#include "pwdutils.h"
 
 #include "logindefs.h"
 
@@ -107,6 +108,7 @@ struct login_context {
 	char		*username;	/* from command line or PAM */
 
 	struct passwd	*pwd;		/* user info */
+	char		*pwdbuf;	/* pwd strings */
 
 	pam_handle_t	*pamh;		/* PAM handler */
 	struct pam_conv	conv;		/* PAM conversation */
@@ -652,26 +654,6 @@ static void log_syslog(struct login_context *cxt)
 	}
 }
 
-static struct passwd *get_passwd_entry(const char *username,
-					 char **pwdbuf,
-					 struct passwd *pwd)
-{
-	struct passwd *res = NULL;
-	int x;
-
-	if (!pwdbuf || !username)
-		return NULL;
-
-	*pwdbuf = xrealloc(*pwdbuf, UL_GETPW_BUFSIZ);
-
-	x = getpwnam_r(username, pwd, *pwdbuf, UL_GETPW_BUFSIZ, &res);
-	if (!res) {
-		errno = x;
-		return NULL;
-	}
-	return res;
-}
-
 /* encapsulate stupid "void **" pam_get_item() API */
 static int loginpam_get_username(pam_handle_t *pamh, char **name)
 {
@@ -1129,9 +1111,7 @@ int main(int argc, char **argv)
 	int childArgc = 0;
 	int retcode;
 	struct sigaction act;
-
-	char *pwdbuf = NULL;
-	struct passwd *pwd = NULL, _pwd;
+	struct passwd *pwd;
 
 	struct login_context cxt = {
 		.tty_mode = TTY_MODE,		  /* tty chmod() */
@@ -1243,7 +1223,8 @@ int main(int argc, char **argv)
 	 */
 	loginpam_acct(&cxt);
 
-	if (!(cxt.pwd = get_passwd_entry(cxt.username, &pwdbuf, &_pwd))) {
+	cxt.pwd = xgetpwnam(cxt.username, &cxt.pwdbuf);
+	if (!cxt.pwd) {
 		warnx(_("\nSession setup problem, abort."));
 		syslog(LOG_ERR, _("Invalid user name \"%s\" in %s:%d. Abort."),
 		       cxt.username, __FUNCTION__, __LINE__);