libs/libc/unistd: add getspnam function

Add getspnam function to pass tlpi example:
https://man7.org/tlpi/code/online/dist/users_groups/check_password.c.html

Signed-off-by: chenzhijia <chenzhijia@xiaomi.com>

include/shadow.h

@@ -0,0 +1,59 @@
+/****************************************************************************
+ * include/shadow.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_SHADOW_H
+#define __INCLUDE_SHADOW_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/compiler.h>
+
+/****************************************************************************
+ * Public Type Declarations
+ ****************************************************************************/
+
+/* Structure of the password file */
+
+struct spwd
+{
+  FAR char *sp_namp;          /* Login name */
+  FAR char *sp_pwdp;          /* Encrypted password */
+  long int sp_lstchg;         /* Date of last change */
+  long int sp_min;            /* Minimum number of days between changes */
+  long int sp_max;            /* Maximum number of days between changes */
+  long int sp_warn;           /* Number of days to warn user to change the password */
+  long int sp_inact;          /* Number of days the account may be inactive */
+  long int sp_expire;         /* Number of days since 1970-01-01 until account expires */
+  unsigned long int sp_flag;  /* Reserved */
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/* Get shadow entry matching NAME */
+
+FAR struct spwd *getspnam(FAR const char *name);
+int getspnam_r(FAR const char *name, FAR struct spwd *sp, FAR char *buf,
+               size_t size, FAR struct spwd **res);
+
+#endif /* __INCLUDE_SHADOW_H */

libs/libc/pwd/CMakeLists.txt

@@ -19,11 +19,17 @@
 # the License.
 #
 # ##############################################################################
-set(SRCS lib_getpwnam.c lib_getpwnamr.c lib_getpwuid.c lib_getpwuidr.c
-         lib_getpwent.c lib_pwd_globals.c)
+set(SRCS
+    lib_getpwnam.c
+    lib_getpwnamr.c
+    lib_getpwuid.c
+    lib_getpwuidr.c
+    lib_getpwent.c
+    lib_pwd_globals.c
+    lib_getspnam.c)
 
 if(CONFIG_LIBC_PASSWD_FILE)
-  list(APPEND SRCS lib_find_pwdfile.c)
+  list(APPEND SRCS lib_find_pwdfile.c lib_getspnamr.c)
 else()
   list(APPEND SRCS lib_getpwbuf.c lib_getpwbufr.c)
 endif()

libs/libc/pwd/Make.defs

@@ -23,10 +23,10 @@
 # Add the pwd C files to the build
 
 CSRCS += lib_getpwnam.c lib_getpwnamr.c lib_getpwuid.c lib_getpwuidr.c
-CSRCS += lib_getpwent.c lib_pwd_globals.c
+CSRCS += lib_getpwent.c lib_pwd_globals.c lib_getspnam.c
 
 ifeq ($(CONFIG_LIBC_PASSWD_FILE),y)
-CSRCS += lib_find_pwdfile.c
+CSRCS += lib_find_pwdfile.c lib_getspnamr.c
 else
 CSRCS += lib_getpwbuf.c lib_getpwbufr.c
 endif

libs/libc/pwd/lib_getspnam.c

@@ -0,0 +1,60 @@
+/****************************************************************************
+ * libs/libc/pwd/lib_getspnam.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <pwd.h>
+#include <shadow.h>
+#include <string.h>
+
+#include "pwd/lib_pwd.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+FAR struct spwd *getspnam(FAR const char *name)
+{
+  FAR struct spwd *result = NULL;
+
+#ifdef CONFIG_LIBC_PASSWD_FILE
+  getspnam_r(name, &g_spwd, g_passwd_buffer,
+             sizeof(g_passwd_buffer), &result);
+#else
+  if (strcmp(name, ROOT_NAME) == 0)
+    {
+      size_t nsize = sizeof(ROOT_NAME);
+      size_t psize = sizeof(ROOT_PWDP);
+      result = &g_spwd;
+
+      result->sp_namp = g_passwd_buffer;
+      result->sp_pwdp = &g_passwd_buffer[nsize];
+
+      strlcpy(result->sp_namp, ROOT_NAME, nsize);
+      strlcpy(result->sp_pwdp, ROOT_PWDP, psize);
+    }
+#endif
+
+  return result;
+}

libs/libc/pwd/lib_getspnamr.c

@@ -0,0 +1,189 @@
+/****************************************************************************
+ * libs/libc/pwd/lib_getspnamr.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <shadow.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define BUFFER_EXTRA 100
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/* This implementation support Openwall-style TCB passwords in place of
+ * traditional shadow, if the appropriate directories and files exist.
+ * Thus, it is careful to avoid following symlinks or blocking on fifos
+ * which a malicious user might create in place of his or her TCB shadow
+ * file. It also avoids any allocation to prevent memory-exhaustion
+ * attacks via huge TCB shadow files
+ */
+
+static long xatol(FAR char **s)
+{
+  if (**s == ':' || **s == '\n')
+    {
+      return -1;
+    }
+
+  return strtol(*s, &(*s), 10);
+}
+
+static int parsespent(FAR char *s, FAR struct spwd *sp)
+{
+  sp->sp_namp = s;
+  if (!(s = strchr(s, ':')))
+    {
+      return -1;
+    }
+
+  *s = 0;
+  sp->sp_pwdp = ++s;
+  if (!(s = strchr(s, ':')))
+    {
+      return -1;
+    }
+
+  *s = 0;
+  s++;
+  sp->sp_lstchg = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_min = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_max = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_warn = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_inact = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_expire = xatol(&s);
+  if (*s != ':')
+    {
+      return -1;
+    }
+
+  s++;
+  sp->sp_flag = xatol(&s);
+  if (*s != '\n')
+    {
+      return -1;
+    }
+
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+int getspnam_r(FAR const char *name, FAR struct spwd *sp, FAR char *buf,
+               size_t size, FAR struct spwd **res)
+{
+  size_t l = strlen(name);
+  size_t k;
+  FAR FILE *f;
+  int skip = 0;
+
+  *res = NULL;
+
+  /* Disallow potentially-malicious user names */
+
+  if (*name == '.' || strchr(name, '/') || l == 0)
+    {
+      set_errno(EINVAL);
+      return -1;
+    }
+
+  /* Buffer size must at least be able to hold name, plus some.. */
+
+  if (size < l + BUFFER_EXTRA)
+    {
+      set_errno(ERANGE);
+      return -1;
+    }
+
+  f = fopen(CONFIG_LIBC_PASSWD_FILEPATH, "rbe");
+  if (f == NULL)
+    {
+      return -1;
+    }
+
+  while (fgets(buf, size, f) && (k = strlen(buf)) > 0)
+    {
+      if (skip || strncmp(name, buf, l) || buf[l] != ':')
+        {
+          skip = buf[k - 1] != '\n';
+          continue;
+        }
+
+      if (buf[k - 1] != '\n')
+        {
+          set_errno(ERANGE);
+          fclose(f);
+          return -1;
+        }
+
+      if (parsespent(buf, sp) < 0)
+        {
+          continue;
+        }
+
+      *res = sp;
+      break;
+    }
+
+  fclose(f);
+  return 0;
+}

libs/libc/pwd/lib_pwd.h

@@ -30,6 +30,7 @@
 #include <nuttx/config.h>
 
 #include <pwd.h>
+#include <shadow.h>
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -46,6 +47,7 @@
 #define ROOT_DIR    "/root"
 #define ROOT_SHELL  "/bin/nsh"
 #define ROOT_PASSWD "root"
+#define ROOT_PWDP   "$1$123$SGj4CnC7VtiFx.tjjtazK1"
 
 /****************************************************************************
  * Public Data
@@ -63,6 +65,7 @@ extern "C"
 
 EXTERN int g_passwd_index;
 EXTERN struct passwd g_passwd;
+EXTERN struct spwd g_spwd;
 EXTERN char g_passwd_buffer[CONFIG_LIBC_PASSWD_LINESIZE];
 
 /****************************************************************************

libs/libc/pwd/lib_pwd_globals.c

@@ -36,6 +36,7 @@
 
 int g_passwd_index;
 struct passwd g_passwd;
+struct spwd g_spwd;
 char g_passwd_buffer[CONFIG_LIBC_PASSWD_LINESIZE];
 
 /****************************************************************************