One simple task pulled on the thread of constification, which rippled…

… throughout

the codebase.  I'm sure there'll be more cleanup of warnings in the contrib
modules; this is just the first pass.

include/auth.h

@@ -1,6 +1,6 @@
 /*
  * ProFTPD - FTP server daemon
- * Copyright (c) 2004-2014 The ProFTPD Project team
+ * Copyright (c) 2004-2016 The ProFTPD Project team
  *
  * 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
@@ -22,9 +22,7 @@
  * the source distribution.
  */
 
-/* ProFTPD Auth API
- * $Id: auth.h,v 1.14 2011-05-23 20:35:35 castaglia Exp $
- */
+/* ProFTPD Auth API */
 
 #ifndef PR_AUTH_H
 #define PR_AUTH_H
@@ -104,7 +102,7 @@ int pr_auth_requires_pass(pool *, const char *);
  * configuration for that user.  If the user name is not be handled as
  * an anonymous login, NULL is returned.
  */
-config_rec *pr_auth_get_anon_config(pool *p, char **, char **, char **);
+config_rec *pr_auth_get_anon_config(pool *p, const char **, char **, char **);
 
 /* Wrapper function around the chroot(2) system call, handles setting of
  * appropriate environment variables if necessary.
@@ -164,7 +162,7 @@ int pr_auth_cache_set(int enable, unsigned int flags);
 /* Wrapper function for retrieving the user's home directory.  This handles
  * any possible RewriteHome configuration.
  */
-char *pr_auth_get_home(pool *, char *pw_dir);
+const char *pr_auth_get_home(pool *, const char *pw_dir);
 
 /* For internal use only. */
 int init_auth(void);

include/cmd.h

@@ -27,7 +27,7 @@
 
 cmd_rec *pr_cmd_alloc(pool *p, int, ...);
 int pr_cmd_clear_cache(cmd_rec *cmd);
-char *pr_cmd_get_displayable_str(cmd_rec *cmd, size_t *len);
+const char *pr_cmd_get_displayable_str(cmd_rec *cmd, size_t *len);
 int pr_cmd_get_errno(cmd_rec *cmd);
 
 int pr_cmd_cmp(cmd_rec *cmd, int cmd_id);

include/dirtree.h

@@ -2,7 +2,7 @@
  * ProFTPD - FTP server daemon
  * Copyright (c) 1997, 1998 Public Flood Software
  * Copyright (c) 1999, 2000 MacGyver aka Habeeb J. Dihu <macgyver@tos.net>
- * Copyright (c) 2001-2015 The ProFTPD Project team
+ * Copyright (c) 2001-2016 The ProFTPD Project team
  *
  * 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
@@ -226,14 +226,14 @@ int dir_check(pool *, cmd_rec *, const char *, const char *, int *);
 int dir_check_canon(pool *, cmd_rec *, const char *, const char *, int *);
 int is_dotdir(const char *);
 int login_check_limits(xaset_t *, int, int, int *);
-char *path_subst_uservar(pool *, char **);
+const char *path_subst_uservar(pool *, const char **);
 void resolve_anonymous_dirs(xaset_t *);
 void resolve_deferred_dirs(server_rec *);
 void fixup_dirs(server_rec *, int);
 unsigned char check_context(cmd_rec *, int);
 char *get_context_name(cmd_rec *);
 int get_boolean(cmd_rec *, int);
-char *get_full_cmd(cmd_rec *);
+const char *get_full_cmd(cmd_rec *);
 
 /* Internal use only. */
 void init_dirtree(void);

include/modules.h

@@ -2,7 +2,7 @@
  * ProFTPD - FTP server daemon
  * Copyright (c) 1997, 1998 Public Flood Software
  * Copyright (c) 1999, 2000 MacGyver aka Habeeb J. Dihu <macgyver@tos.net>
- * Copyright (c) 2001-2015 The ProFTPD Project team
+ * Copyright (c) 2001-2016 The ProFTPD Project team
  *
  * 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
@@ -34,10 +34,10 @@ typedef struct modret_struc	modret_t;
 
 struct modret_struc {
   module *mr_handler_module;		/* which module handled this? */
-  int    mr_error;			/* !0 if error */
-  char   *mr_numeric;			/* numeric error code */
-  char   *mr_message;			/* text message */
-  void	 *data;				/* add'l data -- undefined */
+  int mr_error;				/* !0 if error */
+  const char *mr_numeric;		/* numeric error code */
+  const char *mr_message;		/* text message */
+  void *data;				/* add'l data -- undefined */
 };
 
 /* The following macros are for creating basic modret_t, and can
@@ -66,7 +66,7 @@ struct modret_struc {
 
 typedef struct conftab_rec {
   char *directive;
-  modret_t *(*handler)(cmd_rec*);
+  modret_t *(*handler)(cmd_rec *);
 
   module *m;				/* Reference to owning module
 					 * set when module is initialized
@@ -107,11 +107,11 @@ typedef struct cmdtab_rec {
 
   /* See above for cmd types. */
   unsigned char cmd_type;
-  char *command;
+  const char *command;
 
   /* Command group. */
-  char *group;
-  modret_t *(*handler)(cmd_rec*);
+  const char *group;
+  modret_t *(*handler)(cmd_rec *);
 
   /* Does this command require authentication? */
   unsigned char requires_auth;
@@ -126,19 +126,19 @@ typedef struct cmdtab_rec {
 
 typedef struct authtab_rec {
   int auth_flags;			/* future use */
-  char *name;
-  modret_t *(*handler)(cmd_rec*);
+  const char *name;
+  modret_t *(*handler)(cmd_rec *);
 
   module *m;
 } authtable;
 
 #define PR_AUTH_FL_REQUIRED		0x00001
 
 struct module_struc {
-  module *next,*prev;
+  module *next, *prev;
 
   int api_version;			/* API version _not_ module version */
-  char *name;				/* Module name */
+  const char *name;			/* Module name */
 
   struct conftab_rec *conftable;	/* Configuration directive table */
   struct cmdtab_rec *cmdtable;		/* Command table */
@@ -147,7 +147,7 @@ struct module_struc {
   int (*init)(void); 			/* Module initialization */
   int (*sess_init)(void);		/* Session initialization */
 
-  char *module_version;			/* Module version */
+  const char *module_version;		/* Module version */
   void *handle;				/* Module handle */
 
   /* Internal use; high number == higher priority. */
@@ -158,7 +158,7 @@ struct module_struc {
 
 /* Prototypes */
 
-unsigned char command_exists(char *);
+unsigned char command_exists(const char *);
 int modules_init(void);
 void modules_list(int flags);
 void modules_list2(int (*listf)(const char *, ...), int flags);
@@ -186,12 +186,12 @@ void set_auth_check(int (*ck)(cmd_rec *));
 extern int (*cmd_auth_chk)(cmd_rec *);
 
 /* For use from inside module handler functions */
-modret_t *mod_create_ret(cmd_rec *, unsigned char, char *, char *);
+modret_t *mod_create_ret(cmd_rec *, unsigned char, const char *, const char *);
 modret_t *mod_create_error(cmd_rec *, int);
 modret_t *mod_create_data(cmd_rec *, void *);
 
 /* Implemented in mod_core.c */
-int core_chgrp(cmd_rec *, char *, uid_t, gid_t);
-int core_chmod(cmd_rec *, char *, mode_t);
+int core_chgrp(cmd_rec *, const char *, uid_t, gid_t);
+int core_chmod(cmd_rec *, const char *, mode_t);
 
 #endif /* PR_MODULES_H */

include/proftpd.h

@@ -109,7 +109,7 @@ typedef struct {
   uid_t fsuid;				/* Saved file UID */
   gid_t fsgid;				/* Saved file GID */
 
-  char *user, *group;			/* Username/groupname after login */
+  const char *user, *group;		/* Username/groupname after login */
   uid_t login_uid;                      /* UID after login, but before
                                          * session.uid is changed
                                          */
@@ -120,7 +120,7 @@ typedef struct {
   pr_table_t *notes;			/* Session notes table */
 
   pr_class_t *conn_class;		/* Session class */
-  char *proc_prefix;			/* The "prefix" of our process name */
+  const char *proc_prefix;		/* The "prefix" of our process name */
 
   int wtmp_log;				/* Are we logging to wtmp? */
   int multiline_rfc2228;		/* Are we using RFC2228-style multiline responses ? */
@@ -130,12 +130,12 @@ typedef struct {
 
   int hide_password;			/* Hide password in logs/ps listing */
 
-  char *chroot_path;			/* Chroot directory */
+  const char *chroot_path;		/* Chroot directory */
 
   struct config_struc *anon_config;	/* Anonymous FTP configuration */
-  char *anon_user;			/* E-mail address sent to us */
+  const char *anon_user;		/* Email address sent to us */
 
-  char *curr_cmd;                       /* Current FTP command */
+  const char *curr_cmd;			/* Current FTP command */
   int curr_cmd_id;			/* Current FTP command ID */
   struct cmd_struc *curr_cmd_rec;       /* Current command */
 
@@ -152,17 +152,17 @@ typedef struct {
 
     int xfer_type;     /* xfer session attributes, default/append/hidden */
     int direction;
-    char *filename;			/* As shown to user */
-    char *path;				/* As used in transfer */
-    char *path_hidden;			/* As used in hidden stor */
+    const char *filename;		/* As shown to user */
+    const char *path;			/* As used in transfer */
+    const char *path_hidden;		/* As used in hidden stor */
 
-    unsigned int bufsize,buflen;
+    unsigned int bufsize, buflen;
 
     struct timeval start_time;		/* Time current transfer started */
     off_t file_size;			/* Total size of file (if known) */
     off_t total_bytes;			/* Total bytes transfered */
 
-    char *bufstart,*buf;
+    char *bufstart, *buf;
   } xfer;
 
   /* Total number of bytes uploaded in this session. */

include/session.h

@@ -1,6 +1,6 @@
 /*
  * ProFTPD - FTP server daemon
- * Copyright (c) 2009-2014 The ProFTPD Project team
+ * Copyright (c) 2009-2016 The ProFTPD Project team
  *
  * 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
@@ -25,8 +25,7 @@
 #ifndef PR_SESSION_H
 #define PR_SESSION_H
 
-/* List of disconnect/end-of-session reason codes.
- */
+/* List of disconnect/end-of-session reason codes. */
 
 /* Unknown/unspecified reason for disconnection */
 #define PR_SESS_DISCONNECT_UNSPECIFIED		0
@@ -77,7 +76,7 @@
  * the session ended.  If a pointer to a char * was provided, any extra
  * disconnect details will be provided.
  */
-const char *pr_session_get_disconnect_reason(char **details);
+const char *pr_session_get_disconnect_reason(const char **details);
 
 /* Returns the current protocol name in use.
  *

include/str.h

@@ -38,7 +38,7 @@
 const char *quote_dir(pool *p, char *dir);
 
 char *sstrcat(char *, const char *, size_t);
-char *sreplace(pool *, char *, ...);
+const char *sreplace(pool *, const char *, ...);
 
 char *pdircat(pool *, ...);
 char *pstrcat(pool *, ...);
@@ -57,8 +57,11 @@ char *pstrndup(pool *, const char *, size_t);
 int pr_strnrstr(const char *s, size_t slen, const char *suffix,
   size_t suffixlen, int flags);
 
+/* Returns a quoted version of the given string. */
+const char *pr_str_quote(pool *p, const char *str);
+
 /* Newer version of sreplace(), with more control and better error reporting. */
-char *pr_str_replace(pool *, unsigned int, char *, ...);
+const char *pr_str_replace(pool *, unsigned int, const char *, ...);
 char *pr_str_strip(pool *, char *);
 char *pr_str_strip_end(char *, char *);
 int pr_str_get_nbytes(const char *, const char *, off_t *);