util: Add a UNIX platform independent samba_getpass().

Reviewed-by: Jelmer Vernooij <jelmer@samba.org>

3 files changed, 265 insertions, 1 deletions

diff --git a/lib/util/getpass.c b/lib/util/getpass.c
new file mode 100644
index 0000000000..480bd56898
--- /dev/null
+++ b/lib/util/getpass.c
@@ -0,0 +1,224 @@
+/*
+ *  Unix SMB/CIFS implementation.
+ *
+ *  getpass.c - platform independent getpass function.
+ *
+ *  Copyright (c) 2010-2012 Andreas Schneider <asn@samba.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+
+#include "system/filesys.h"
+#include "system/terminal.h"
+
+#if !defined(SMB_MALLOC)
+#undef malloc
+#define SMB_MALLOC(s) malloc((s))
+#endif
+
+/**
+ * @internal
+ *
+ * @brief Get the password from the console.
+ *
+ * @param[in]  prompt   The prompt to display.
+ *
+ * @param[in]  buf      The buffer to fill.
+ *
+ * @param[in]  len      The length of the buffer.
+ *
+ * @param[in]  verify   Should the password be verified?
+ *
+ * @return              1 on success, 0 on error.
+ */
+static int samba_gets(const char *prompt, char *buf, size_t len, bool verify)
+{
+	char *tmp;
+	char *ptr = NULL;
+	int ok = 0;
+
+	tmp = SMB_MALLOC(len);
+	if (tmp == NULL) {
+		return 0;
+	}
+	memset(tmp,'\0',len);
+
+	/* read the password */
+	while (!ok) {
+		if (buf[0] != '\0') {
+			fprintf(stdout, "%s[%s] ", prompt, buf);
+		} else {
+			fprintf(stdout, "%s", prompt);
+		}
+		fflush(stdout);
+		if (fgets(tmp, len, stdin) == NULL) {
+			free(tmp);
+			return 0;
+		}
+
+		if ((ptr = strchr(tmp, '\n'))) {
+			*ptr = '\0';
+		}
+		fprintf(stdout, "\n");
+
+		if (*tmp) {
+			strncpy(buf, tmp, len);
+		}
+
+		if (verify) {
+			char *key_string;
+
+			key_string = SMB_MALLOC(len);
+			if (key_string == NULL) {
+				break;
+			}
+			memset(key_string, '\0', len);
+
+			fprintf(stdout, "\nVerifying, please re-enter. %s", prompt);
+			fflush(stdout);
+			if (! fgets(key_string, len, stdin)) {
+				memset(key_string, '\0', len);
+				SAFE_FREE(key_string);
+				clearerr(stdin);
+				continue;
+			}
+			if ((ptr = strchr(key_string, '\n'))) {
+				*ptr = '\0';
+			}
+			fprintf(stdout, "\n");
+			if (strcmp(buf, key_string)) {
+				printf("\n\07\07Mismatch - try again\n");
+				memset(key_string, '\0', len);
+				SAFE_FREE(key_string);
+				fflush(stdout);
+				continue;
+			}
+			memset(key_string, '\0', len);
+			SAFE_FREE(key_string);
+		}
+		ok = 1;
+	}
+	memset(tmp, '\0', len);
+	free(tmp);
+
+	return ok;
+}
+
+/**
+ * @brief Get a password from the console.
+ *
+ * You should make sure that the buffer is an empty string!
+ *
+ * You can also use this function to ask for a username. Then you can fill the
+ * buffer with the username and it is shows to the users. If the users just
+ * presses enter the buffer will be untouched.
+ *
+ * @code
+ *   char username[128];
+ *
+ *   snprintf(username, sizeof(username), "john");
+ *
+ *   samba_getpass("Username:", username, sizeof(username), 1, 0);
+ * @endcode
+ *
+ * The prompt will look like this:
+ *
+ *   Username: [john]
+ *
+ * If you press enter then john is used as the username, or you can type it in
+ * to change it.
+ *
+ * @param[in]  prompt   The prompt to show to ask for the password.
+ *
+ * @param[out] buf    The buffer the password should be stored. It NEEDS to be
+ *                      empty or filled out.
+ *
+ * @param[in]  len      The length of the buffer.
+ *
+ * @param[in]  echo     Should we echo what you type.
+ *
+ * @param[in]  verify   Should we ask for the password twice.
+ *
+ * @return              0 on success, -1 on error.
+ */
+int samba_getpass(const char *prompt,
+		  char *buf,
+		  size_t len,
+		  bool echo,
+		  bool verify)
+{
+	struct termios attr;
+	struct termios old_attr;
+	int ok = 0;
+	int fd = -1;
+
+	/* fgets needs at least len - 1 */
+	if (prompt == NULL || buf == NULL || len < 2) {
+		return -1;
+	}
+
+	ZERO_STRUCT(attr);
+	ZERO_STRUCT(old_attr);
+
+	/* get local terminal attributes */
+	if (tcgetattr(STDIN_FILENO, &attr) < 0) {
+		perror("tcgetattr");
+		return -1;
+	}
+
+	/* save terminal attributes */
+	memcpy(&old_attr, &attr, sizeof(attr));
+	if((fd = fcntl(0, F_GETFL, 0)) < 0) {
+		perror("fcntl");
+		return -1;
+	}
+
+	/* disable echo */
+	if (!echo) {
+		attr.c_lflag &= ~(ECHO);
+	}
+
+	/* write attributes to terminal */
+	if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr) < 0) {
+		perror("tcsetattr");
+		return -1;
+	}
+
+	/* disable nonblocking I/O */
+	if (fd & O_NDELAY) {
+		fcntl(0, F_SETFL, fd & ~O_NDELAY);
+	}
+
+	ok = samba_gets(prompt, buf, len, verify);
+
+	/* reset terminal */
+	tcsetattr(STDIN_FILENO, TCSANOW, &old_attr);
+
+	/* close fd */
+	if (fd & O_NDELAY) {
+		fcntl(0, F_SETFL, fd);
+	}
+
+	if (!ok) {
+		memset (buf, '\0', len);
+		return -1;
+	}
+
+	/* force termination */
+	buf[len - 1] = '\0';
+
+	return 0;
+}
diff --git a/lib/util/samba_util.h b/lib/util/samba_util.h
index 4a6dd3bc80..e553ec1342 100644
--- a/lib/util/samba_util.h
+++ b/lib/util/samba_util.h
@@ -817,6 +817,46 @@ _PUBLIC_ void close_low_fds(bool stdin_too, bool stdout_too, bool stderr_too);
 _PUBLIC_ void become_daemon(bool do_fork, bool no_process_group, bool log_stdout);
 
 /**
+ * @brief Get a password from the console.
+ *
+ * You should make sure that the buffer is an empty string!
+ *
+ * You can also use this function to ask for a username. Then you can fill the
+ * buffer with the username and it is shows to the users. If the users just
+ * presses enter the buffer will be untouched.
+ *
+ * @code
+ *   char username[128];
+ *
+ *   snprintf(username, sizeof(username), "john");
+ *
+ *   smb_getpass("Username:", username, sizeof(username), 1, 0);
+ * @endcode
+ *
+ * The prompt will look like this:
+ *
+ *   Username: [john]
+ *
+ * If you press enter then john is used as the username, or you can type it in
+ * to change it.
+ *
+ * @param[in]  prompt   The prompt to show to ask for the password.
+ *
+ * @param[out] buf    The buffer the password should be stored. It NEEDS to be
+ *                      empty or filled out.
+ *
+ * @param[in]  len      The length of the buffer.
+ *
+ * @param[in]  echo     Should we echo what you type.
+ *
+ * @param[in]  verify   Should we ask for the password twice.
+ *
+ * @return              0 on success, -1 on error.
+ */
+_PUBLIC_ int samba_getpass(const char *prompt, char *buf, size_t len,
+			   bool echo, bool verify);
+
+/**
  * Load a ini-style file.
  */
 bool pm_process( const char *fileName,
diff --git a/lib/util/wscript_build b/lib/util/wscript_build
index ddaf90ffc2..a671bc9c36 100755
--- a/lib/util/wscript_build
+++ b/lib/util/wscript_build
@@ -2,7 +2,7 @@
 
 bld.SAMBA_LIBRARY('samba-util',
                   source='''talloc_stack.c smb_threads.c xfile.c data_blob.c
-                    util_file.c time.c rbtree.c rfc1738.c select.c
+                    util_file.c time.c rbtree.c rfc1738.c select.c getpass.c
                     genrand.c fsusage.c blocking.c become_daemon.c
                     signal.c system.c params.c util.c util_id.c util_net.c
                     util_strlist.c util_paths.c idtree.c debug.c fault.c base64.c