pwd: Add initial implementation of getpwent

fix ltp sigqueue testcase crash in getpwent:
nsh> ltp_sigqueue_3_1
core dumped

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

include/pwd.h

@@ -67,6 +67,12 @@ extern "C"
 #define EXTERN extern
 #endif
 
+void setpwent(void);
+void endpwent(void);
+FAR struct passwd *getpwent(void);
+int getpwent_r(FAR struct passwd *pwd,
+               FAR char *buf, size_t buflen,
+               FAR struct passwd **result);
 FAR struct passwd *getpwnam(FAR const char *name);
 FAR struct passwd *getpwuid(uid_t uid);
 int getpwnam_r(FAR const char *name, FAR struct passwd *pwd, FAR char *buf,

libs/libc/pwd/Make.defs

@@ -21,10 +21,10 @@
 # Add the pwd C files to the build
 
 CSRCS += lib_getpwnam.c lib_getpwnamr.c lib_getpwuid.c lib_getpwuidr.c
-CSRCS += lib_pwd_globals.c
+CSRCS += lib_getpwent.c lib_pwd_globals.c
 
 ifeq ($(CONFIG_LIBC_PASSWD_FILE),y)
-CSRCS += lib_find_pwdfile.c lib_pwd_globals.c
+CSRCS += lib_find_pwdfile.c
 else
 CSRCS += lib_getpwbuf.c lib_getpwbufr.c
 endif

libs/libc/pwd/lib_find_pwdfile.c

@@ -37,7 +37,7 @@
  ****************************************************************************/
 
 typedef CODE int (pwd_foreach_match_t)(FAR const struct passwd *entry,
-                                       uintptr_t arg);
+                                       uintptr_t index, uintptr_t arg);
 
 /****************************************************************************
  * Private Functions
@@ -52,6 +52,7 @@ typedef CODE int (pwd_foreach_match_t)(FAR const struct passwd *entry,
  *
  * Input Parameters:
  *   entry  - The parsed passwd file record
+ *   index  - The index of record in passwd file
  *   arg    - A pointer to the user name to match
  *
  * Returned Value:
@@ -61,8 +62,11 @@ typedef CODE int (pwd_foreach_match_t)(FAR const struct passwd *entry,
  *
  ****************************************************************************/
 
-static int pwd_match_name(FAR const struct passwd *entry, uintptr_t arg)
+static int pwd_match_name(FAR const struct passwd *entry,
+                          uintptr_t index, uintptr_t arg)
 {
+  UNUSED(index);
+
   FAR const char *uname = (FAR const char *)arg;
   return strcmp(entry->pw_name, uname) == 0 ? 1 : 0;
 }
@@ -76,6 +80,7 @@ static int pwd_match_name(FAR const struct passwd *entry, uintptr_t arg)
  *
  * Input Parameters:
  *   entry  - The parsed passwd file record
+ *   index  - The index of record in passwd file
  *   arg    - The user ID to match
  *
  * Returned Value:
@@ -85,12 +90,41 @@ static int pwd_match_name(FAR const struct passwd *entry, uintptr_t arg)
  *
  ****************************************************************************/
 
-static int pwd_match_uid(FAR const struct passwd *entry, uintptr_t arg)
+static int pwd_match_uid(FAR const struct passwd *entry,
+                         uintptr_t index, uintptr_t arg)
 {
+  UNUSED(index);
+
   int match_uid = (int)arg;
   return match_uid == entry->pw_uid ? 1 : 0;
 }
 
+/****************************************************************************
+ * Name: pwd_match_index
+ *
+ * Description:
+ *   Called for each record in the passwd file.  Returns "1" if the record
+ *   matches the index (passed as arg)
+ *
+ * Input Parameters:
+ *   entry  - The parsed passwd file record
+ *   index  - The index of record in passwd file
+ *   arg    - The index to match
+ *
+ * Returned Value:
+ *   = 0 :  No entry name does not match.
+ *   = 1 :  The entry name matches
+ *
+ ****************************************************************************/
+
+static int pwd_match_index(FAR const struct passwd *entry,
+                           uintptr_t index, uintptr_t arg)
+{
+  UNUSED(entry);
+
+  return index == arg;
+}
+
 /****************************************************************************
  * Name: pwd_foreach
  *
@@ -118,6 +152,7 @@ static int pwd_foreach(pwd_foreach_match_t match, uintptr_t arg,
   FAR FILE *stream;
   FAR char *ptr;
   FAR char *save;
+  int index = 0;
   int ret;
 
   stream = fopen(CONFIG_LIBC_PASSWD_FILEPATH, "r");
@@ -255,7 +290,7 @@ static int pwd_foreach(pwd_foreach_match_t match, uintptr_t arg,
 
       /* Check for a match */
 
-      ret = match(entry, arg);
+      ret = match(entry, (uintptr_t)index++, arg);
       if (ret != 0)
         {
           /* We either have the match or an error occurred. */
@@ -333,3 +368,29 @@ int pwd_findby_uid(uid_t uid, FAR struct passwd *entry, FAR char *buffer,
 
   return pwd_foreach(pwd_match_uid, (uintptr_t)uid, entry, buffer, buflen);
 }
+
+/****************************************************************************
+ * Name: pwd_findby_index
+ *
+ * Description:
+ *   Find passwd file entry using the index.
+ *
+ * Input Parameters:
+ *   index  - The index of entry
+ *   entry  - Location to return the parsed passwd file entry
+ *   buffer - I/O buffer used to access the passwd file
+ *   buflen - The size of the I/O buffer in bytes
+ *
+ * Returned Value:
+ *   < 0 :  An error has occurred.
+ *   = 0 :  No entry with this name was found.
+ *   = 1 :  The entry with this name was found.
+ *
+ ****************************************************************************/
+
+int pwd_findby_index(int index, FAR struct passwd *entry,
+                     FAR char *buffer, size_t buflen)
+{
+  return pwd_foreach(pwd_match_index, (uintptr_t)index,
+                     entry, buffer, buflen);
+}

libs/libc/pwd/lib_getpwent.c

@@ -0,0 +1,165 @@
+/****************************************************************************
+ * libs/libc/pwd/lib_getpwent.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 <string.h>
+#include <pwd.h>
+#include <errno.h>
+
+#include "pwd/lib_pwd.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: setpwent
+ *
+ * Description:
+ *   The setpwent() function rewinds to the beginning of the password
+ *   database.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void setpwent(void)
+{
+  g_passwd_index = 0;
+}
+
+/****************************************************************************
+ * Name: endpwent
+ *
+ * Description:
+ *   The endpwent() function is used to close the password database after
+ *   all processing has been performed.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void endpwent(void)
+{
+  g_passwd_index = 0;
+}
+
+/****************************************************************************
+ * Name: getpwent
+ *
+ * Description:
+ *   The getpwent() function returns a pointer to a structure
+ *   containing the broken-out fields of a record from the password
+ *   database.
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   The getpwent() function returns a pointer to a passwd structure,
+ *   or NULL if there are no more entries or an error occurred.  If an
+ *   error occurs, errno is set to indicate the error.  If one wants
+ *   to check errno after the call, it should be set to zero before
+ *   the call.
+ *
+ ****************************************************************************/
+
+FAR struct passwd *getpwent(void)
+{
+  FAR struct passwd *pwd;
+  getpwent_r(&g_passwd, g_passwd_buffer,
+             CONFIG_LIBC_PASSWD_LINESIZE, &pwd);
+  return pwd;
+}
+
+/****************************************************************************
+ * Name: getpwent_r
+ *
+ * Description:
+ *   The functions getpwent_r() are the reentrant versions of getpwent().
+ *   The former reads the next passwd entry from the stream
+ *   initialized by setpwent().
+ *
+ * Input Parameters:
+ *   pwd     - contains the struct passwd that was read from the stream,
+ *             if any.
+ *   buf     - contains additional strings, if any.
+ *   buflen  - specifies the size of buf.
+ *   *result - returns a pointer to the struct passwd in *pwd.
+ *
+ * Returned Value:
+ *   On success, return 0, and *pwbufp shall contain a pointer to the result.
+ *   On failure, *pwbufp shall contain NULL. return an error an follows:
+ *     ENOENT: No more password entries.
+ *     ERANGE: Not enough buffer space. Specify a larger buffer and
+ *             try again.
+ *
+ ****************************************************************************/
+
+int getpwent_r(FAR struct passwd *pwd,
+               FAR char *buf, size_t buflen,
+               FAR struct passwd **result)
+{
+  int ret;
+#ifdef CONFIG_LIBC_PASSWD_FILE
+  ret = pwd_findby_index(g_passwd_index, pwd, buf, buflen);
+  if (ret != 1)
+    {
+      *result = NULL;
+      return ret < 0 ? ret : ENOENT;
+    }
+
+  *result = pwd;
+  g_passwd_index++;
+  return OK;
+#else
+  if (g_passwd_index != 0)
+    {
+      /* The only known user is 'root', if index in not 0. Thus, report
+       * back that no match was found.
+       */
+
+      *result = NULL;
+      return ENOENT;
+    }
+
+  ret = getpwbuf_r(ROOT_UID, ROOT_GID, ROOT_NAME, ROOT_NAME, ROOT_DIR,
+                    ROOT_SHELL, pwd, buf, buflen, result);
+  if (ret == 0)
+    {
+      g_passwd_index++;
+    }
+
+  return ret;
+#endif
+}

libs/libc/pwd/lib_pwd.h

@@ -58,6 +58,7 @@ extern "C"
 
 /* Data for non-reentrant group functions */
 
+EXTERN int g_passwd_index;
 EXTERN struct passwd g_passwd;
 EXTERN char g_passwd_buffer[CONFIG_LIBC_PASSWD_LINESIZE];
 
@@ -78,6 +79,8 @@ int pwd_findby_name(FAR const char *uname, FAR struct passwd *entry,
                     FAR char *buffer, size_t buflen);
 int pwd_findby_uid(uid_t uid, FAR struct passwd *entry, FAR char *buffer,
                    size_t buflen);
+int pwd_findby_index(int index, FAR struct passwd *entry,
+                     FAR char *buffer, size_t buflen)
 #endif
 
 #undef EXTERN

libs/libc/pwd/lib_pwd_globals.c

@@ -32,6 +32,7 @@
 
 /* Data for non-reentrant group functions */
 
+int g_passwd_index;
 struct passwd g_passwd;
 char g_passwd_buffer[CONFIG_LIBC_PASSWD_LINESIZE];