Constification

8 files changed, 49 insertions, 38 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 63f357885..62156137e 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -13,6 +13,11 @@ JH/01 Move the wait-for-next-tick (needed for unique messmage IDs) from
 JH/02 Move from using the pcre library to pcre2.  The former is no longer
       being developed or supported (by the original developer).
 
+JH/03 Constification work in the filters module required a major version
+      bump for the local-scan API.  Specifically, the "headers_charset"
+      global which is visible via the API is now const and may therefore
+      not be modified by local-scan code.
+
 
 Exim version 4.95
 -----------------
diff --git a/src/src/expand.c b/src/src/expand.c
index 88d4e756f..3d48301a1 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -1593,7 +1593,7 @@ Returns:        NULL if the header does not exist, else a pointer to a new
 */
 
 static uschar *
-find_header(uschar *name, int *newsize, unsigned flags, uschar *charset)
+find_header(uschar *name, int *newsize, unsigned flags, const uschar *charset)
 {
 BOOL found = !name;
 int len = name ? Ustrlen(name) : 0;
@@ -4592,7 +4592,7 @@ while (*s)
       unsigned flags = *name == 'r' ? FH_WANT_RAW
 		      : *name == 'l' ? FH_WANT_RAW|FH_WANT_LIST
 		      : 0;
-      uschar * charset = *name == 'b' ? NULL : headers_charset;
+      const uschar * charset = *name == 'b' ? NULL : headers_charset;
 
       s = read_header_name(name, sizeof(name), s);
       value = find_header(name, &newsize, flags, charset);
diff --git a/src/src/filter.c b/src/src/filter.c
index dfcc80271..1dbae43e9 100644
--- a/src/src/filter.c
+++ b/src/src/filter.c
@@ -1993,16 +1993,19 @@ while (commands)
 	s = expargs[0];
 
 	if (filter_test != FTEST_NONE)
-	  printf("Headers %s \"%s\"\n", (subtype == TRUE)? "add" :
-	    (subtype == FALSE)? "remove" : "charset", string_printing(s));
+	  printf("Headers %s \"%s\"\n",
+	    subtype == TRUE ? "add"
+	    : subtype == FALSE ? "remove"
+	    : "charset",
+	    string_printing(s));
 
 	if (subtype == TRUE)
 	  {
 	  while (isspace(*s)) s++;
-	  if (s[0] != 0)
+	  if (*s)
 	    {
-	    header_add(htype_other, "%s%s", s, (s[Ustrlen(s)-1] == '\n')?
-	      "" : "\n");
+	    header_add(htype_other, "%s%s", s,
+	      s[Ustrlen(s)-1] == '\n' ? "" : "\n");
 	    header_last->type = header_checkname(header_last, FALSE);
 	    if (header_last->type >= 'a') header_last->type = htype_other;
 	    }
@@ -2020,7 +2023,7 @@ while (commands)
 	/* This setting lasts only while the filter is running; on exit, the
 	variable is reset to the previous value. */
 
-	else headers_charset = s;	/*XXX loses track of const */
+	else headers_charset = s;
 	}
       break;
 
@@ -2043,18 +2046,18 @@ while (commands)
       ff_name = US"freeze";
       ff_ret = FF_FREEZE;
 
-      DEFERFREEZEFAIL:
-      fmsg = expargs[0];		/*XXX loses track of const */
-      if (Ustrlen(fmsg) > 1024) Ustrcpy(fmsg + 1000, US" ... (truncated)");
-      fmsg = US string_printing(fmsg);
-      *error_pointer = fmsg;
+    DEFERFREEZEFAIL:
+      *error_pointer = fmsg = US string_printing(Ustrlen(expargs[0]) > 1024
+	? string_sprintf("%.1000s ... (truncated)", expargs[0])
+	: string_copy(expargs[0]));
 
       if (filter_test != FTEST_NONE)
 	{
 	indent();
 	printf("%c%s text \"%s\"\n", toupper(ff_name[0]), ff_name+1, fmsg);
 	}
-      else DEBUG(D_filter) debug_printf_indent("Filter: %s \"%s\"\n", ff_name, fmsg);
+      else
+        DEBUG(D_filter) debug_printf_indent("Filter: %s \"%s\"\n", ff_name, fmsg);
       return ff_ret;
 
     case finish_command:
@@ -2064,19 +2067,19 @@ while (commands)
 	printf("%sinish\n", (commands->seen)? "Seen f" : "F");
 	}
       else
-	{
 	DEBUG(D_filter) debug_printf_indent("Filter: %sfinish\n",
-	  (commands->seen)? " Seen " : "");
-	}
+	  commands->seen ? " Seen " : "");
       finish_obeyed = TRUE;
-      return filter_delivered? FF_DELIVERED : FF_NOTDELIVERED;
+      return filter_delivered ? FF_DELIVERED : FF_NOTDELIVERED;
 
     case if_command:
 	{
 	uschar *save_address = filter_thisaddress;
 	int ok = FF_DELIVERED;
 	condition_value = test_condition(commands->args[0].c, TRUE);
-	if (*error_pointer != NULL) ok = FF_ERROR; else
+	if (*error_pointer)
+	  ok = FF_ERROR;
+	else
 	  {
 	  output_indent += 2;
 	  ok = interpret_commands(commands->args[condition_value? 1:2].f,
@@ -2084,7 +2087,7 @@ while (commands)
 	  output_indent -= 2;
 	  }
 	filter_thisaddress = save_address;
-	if (finish_obeyed || (ok != FF_DELIVERED && ok != FF_NOTDELIVERED))
+	if (finish_obeyed  ||  ok != FF_DELIVERED && ok != FF_NOTDELIVERED)
 	  return ok;
 	}
       break;
@@ -2096,7 +2099,7 @@ while (commands)
 
     case mail_command:
     case vacation_command:
-	if (return_path == NULL || return_path[0] == 0)
+	if (!return_path || !*return_path)
 	  {
 	  if (filter_test != FTEST_NONE)
 	    printf("%s command ignored because return_path is empty\n",
@@ -2126,10 +2129,10 @@ while (commands)
 
 	for (i = 0; i < MAILARGS_STRING_COUNT; i++)
 	  {
-	  uschar *p;
+	  const uschar *p;
 	  const uschar *s = expargs[i];
 
-	  if (s == NULL) continue;
+	  if (!s) continue;
 
 	  if (i != mailarg_index_text) for (p = s; *p != 0; p++)
 	    {
@@ -2161,12 +2164,12 @@ while (commands)
 
 	      else
 		{
-		uschar *pp;
+		const uschar *pp;
 		for (pp = p + 1;; pp++)
 		  {
 		  c = *pp;
 		  if (c == ':' && pp != p + 1) break;
-		  if (c == 0 || c == ':' || isspace(*pp))
+		  if (!c || c == ':' || isspace(c))
 		    {
 		    *error_pointer = string_sprintf("\\n not followed by space or "
 		      "valid header name in \"%.1024s\" in %s command",
@@ -2196,7 +2199,7 @@ while (commands)
 	    commands->noerror ? " (noerror)" : "");
 	  for (i = 1; i < MAILARGS_STRING_COUNT; i++)
 	    {
-	    uschar *arg = commands->args[i].u;
+	    const uschar *arg = commands->args[i].u;
 	    if (arg)
 	      {
 	      int len = Ustrlen(mailargs[i]);
@@ -2505,7 +2508,7 @@ filter_interpret(uschar *filter, int options, address_item **generated,
 int i;
 int yield = FF_ERROR;
 uschar *ptr = filter;
-uschar *save_headers_charset = headers_charset;
+const uschar *save_headers_charset = headers_charset;
 filter_cmd *commands = NULL;
 filter_cmd **lastcmdptr = &commands;
 
diff --git a/src/src/functions.h b/src/src/functions.h
index a51998864..43424061a 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -378,7 +378,8 @@ extern uschar *parse_find_address_end(const uschar *, BOOL);
 extern const uschar *parse_find_at(const uschar *);
 extern const uschar *parse_fix_phrase(const uschar *, int);
 extern const uschar *parse_message_id(const uschar *, uschar **, uschar **);
-extern const uschar *parse_quote_2047(const uschar *, int, uschar *, BOOL);
+extern const uschar *parse_quote_2047(const uschar *, int, const uschar *,
+				      BOOL);
 extern const uschar *parse_date_time(const uschar *str, time_t *t);
 extern void priv_drop_temp(const uid_t, const gid_t);
 extern void priv_restore(void);
@@ -444,8 +445,8 @@ extern header_line *rewrite_header(header_line *,
 extern const uschar *rewrite_one(const uschar *, int, BOOL *, BOOL, uschar *,
                  rewrite_rule *);
 extern void    rewrite_test(const uschar *);
-extern uschar *rfc2047_decode2(uschar *, BOOL, uschar *, int, int *, int *,
-                 uschar **);
+extern uschar *rfc2047_decode2(uschar *, BOOL, const uschar *, int, int *,
+				     int *, uschar **);
 extern int     route_address(address_item *, address_item **, address_item **,
                  address_item **, address_item **, int);
 extern int     route_check_prefix(const uschar *, const uschar *, unsigned *);
diff --git a/src/src/globals.c b/src/src/globals.c
index 7dfbc7608..19269138c 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -953,7 +953,7 @@ volatile sig_atomic_t had_command_timeout = 0;
 volatile sig_atomic_t had_command_sigterm = 0;
 volatile sig_atomic_t had_data_timeout    = 0;
 volatile sig_atomic_t had_data_sigint     = 0;
-uschar *headers_charset        = US HEADERS_CHARSET;
+const uschar *headers_charset  = US HEADERS_CHARSET;
 int     header_insert_maxlen   = 64 * 1024;
 header_line  *header_last      = NULL;
 header_line  *header_list      = NULL;
diff --git a/src/src/local_scan.h b/src/src/local_scan.h
index cb50a6809..3efe94941 100644
--- a/src/src/local_scan.h
+++ b/src/src/local_scan.h
@@ -40,7 +40,7 @@ ABI is changed in a non backward compatible way. The minor number is increased
 each time a new feature is added (in a way that doesn't break backward
 compatibility). */
 
-#define LOCAL_SCAN_ABI_VERSION_MAJOR 4
+#define LOCAL_SCAN_ABI_VERSION_MAJOR 5
 #define LOCAL_SCAN_ABI_VERSION_MINOR 1
 #define LOCAL_SCAN_ABI_VERSION \
   LOCAL_SCAN_ABI_VERSION_MAJOR.LOCAL_SCAN_ABI_VERSION_MINOR
@@ -160,7 +160,7 @@ extern unsigned int debug_selector;    /* Debugging bits */
 extern int     body_linecount;         /* Line count in body */
 extern int     body_zerocount;         /* Binary zero count in body */
 extern uschar *expand_string_message;  /* Error info for failing expansion */
-extern uschar *headers_charset;        /* Charset for RFC 2047 decoding */
+extern const uschar *headers_charset;  /* Charset for RFC 2047 decoding */
 extern header_line *header_last;       /* Final header */
 extern header_line *header_list;       /* First header */
 extern BOOL    host_checking;          /* Set when checking a host */
@@ -198,7 +198,8 @@ extern int     lss_match_address(uschar *, uschar *, BOOL);
 extern int     lss_match_host(uschar *, uschar *, uschar *);
 extern void    receive_add_recipient(uschar *, int);
 extern BOOL    receive_remove_recipient(uschar *);
-extern uschar *rfc2047_decode(uschar *, BOOL, uschar *, int, int *, uschar **);
+extern uschar *rfc2047_decode(uschar *, BOOL, const uschar *, int, int *,
+			      uschar **);
 extern int     smtp_fflush(void);
 extern void    smtp_printf(const char *, BOOL, ...) PRINTF_FUNCTION(1,3);
 extern void    smtp_vprintf(const char *, BOOL, va_list);
diff --git a/src/src/parse.c b/src/src/parse.c
index 58f894199..352f07d60 100644
--- a/src/src/parse.c
+++ b/src/src/parse.c
@@ -863,7 +863,8 @@ Returns:       pointer to the original string, if no quoting needed, or
 */
 
 const uschar *
-parse_quote_2047(const uschar *string, int len, uschar *charset, BOOL fold)
+parse_quote_2047(const uschar *string, int len, const uschar *charset,
+  BOOL fold)
 {
 const uschar * s = string;
 int hlen, l;
diff --git a/src/src/rfc2047.c b/src/src/rfc2047.c
index 6c461029b..c3cf4db11 100644
--- a/src/src/rfc2047.c
+++ b/src/src/rfc2047.c
@@ -186,8 +186,8 @@ Returns:         the decoded, converted string, or NULL on error; if there are
 */
 
 uschar *
-rfc2047_decode2(uschar *string, BOOL lencheck, uschar *target, int zeroval,
-  int *lenptr, int *sizeptr, uschar **error)
+rfc2047_decode2(uschar *string, BOOL lencheck, const uschar *target,
+  int zeroval, int *lenptr, int *sizeptr, uschar **error)
 {
 int size = Ustrlen(string);
 size_t dlen;
@@ -336,7 +336,7 @@ return string_from_gstring(yield);
 argument. */
 
 uschar *
-rfc2047_decode(uschar *string, BOOL lencheck, uschar *target, int zeroval,
+rfc2047_decode(uschar *string, BOOL lencheck, const uschar *target, int zeroval,
   int *lenptr, uschar **error)
 {
 return rfc2047_decode2(string, lencheck, target, zeroval, lenptr, NULL, error);