From ab53883c94f94958e22077c79ba1dae1850a475e Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Fri, 10 Jan 2020 20:44:48 +0000
Subject: [PATCH] Enhance --conf-dir to load files in a deterministic order.

---
 CHANGELOG     |  3 +++
 man/dnsmasq.8 |  2 +-
 src/option.c  | 47 +++++++++++++++++++++++++++++++++--------------
 3 files changed, 37 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 570eb46..42ad123 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -61,6 +61,9 @@ version 2.81
 	Thanks to Dereck Higgins for spotting this.
 
 	Add --tftp-single-port option.
+
+	Enhance --conf-dir to load files in a deterministic order. Thanks to
+	Evgenii Seliavka for the suggestion and initial patch.
 	
 
 version 2.80
diff --git a/man/dnsmasq.8 b/man/dnsmasq.8
index 744eb5e..cb5cc73 100644
--- a/man/dnsmasq.8
+++ b/man/dnsmasq.8
@@ -1967,7 +1967,7 @@ which have that extension are loaded. So
 .B --conf-dir=/path/to/dir,*.conf
 loads all files with the suffix .conf in /path/to/dir. This flag may be given on the command
 line or in a configuration file. If giving it on the command line, be sure to
-escape * characters.
+escape * characters. Files are loaded in alphabetical order of filename.
 .TP
 .B --servers-file=<file>
 A special case of 
diff --git a/src/option.c b/src/option.c
index bce8659..f110b75 100644
--- a/src/option.c
+++ b/src/option.c
@@ -1665,9 +1665,9 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	struct dirent *ent;
 	char *directory, *path;
 	struct list {
-	  char *suffix;
+	  char *name;
 	  struct list *next;
-	} *ignore_suffix = NULL, *match_suffix = NULL, *li;
+	} *ignore_suffix = NULL, *match_suffix = NULL, *files = NULL, *li;
 	
 	comma = split(arg);
 	if (!(directory = opt_string_alloc(arg)))
@@ -1689,7 +1689,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			li->next = match_suffix;
 			match_suffix = li;
 			/* Have to copy: buffer is overwritten */
-			li->suffix = opt_string_alloc(arg+1);
+			li->name = opt_string_alloc(arg+1);
 		      }
 		  }
 		else
@@ -1697,7 +1697,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		    li->next = ignore_suffix;
 		    ignore_suffix = li;
 		    /* Have to copy: buffer is overwritten */
-		    li->suffix = opt_string_alloc(arg);
+		    li->name = opt_string_alloc(arg);
 		  }
 	      }
 	  }
@@ -1722,9 +1722,9 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		for (li = match_suffix; li; li = li->next)
 		  {
 		    /* check for required suffices */
-		    size_t ls = strlen(li->suffix);
+		    size_t ls = strlen(li->name);
 		    if (len > ls &&
-			strcmp(li->suffix, &ent->d_name[len - ls]) == 0)
+			strcmp(li->name, &ent->d_name[len - ls]) == 0)
 		      break;
 		  }
 		if (!li)
@@ -1734,9 +1734,9 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    for (li = ignore_suffix; li; li = li->next)
 	      {
 		/* check for proscribed suffices */
-		size_t ls = strlen(li->suffix);
+		size_t ls = strlen(li->name);
 		if (len > ls &&
-		    strcmp(li->suffix, &ent->d_name[len - ls]) == 0)
+		    strcmp(li->name, &ent->d_name[len - ls]) == 0)
 		  break;
 	      }
 	    if (li)
@@ -1753,25 +1753,44 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    
 	    /* only reg files allowed. */
 	    if (S_ISREG(buf.st_mode))
-	      one_file(path, 0);
-	    
-	    free(path);
+	      {
+		/* sort files into order. */
+		struct list **up, *new = opt_malloc(sizeof(struct list));
+		new->name = path;
+		
+		for (up = &files, li = files; li; up = &li->next, li = li->next)
+		  if (strcmp(li->name, path) >=0)
+		    break;
+
+		new->next = li;
+		*up = new;
+	      }
+
 	  }
-     
+
+	for (li = files; li; li = li->next)
+	  one_file(li->name, 0);
+      	
 	closedir(dir_stream);
 	free(directory);
 	for(; ignore_suffix; ignore_suffix = li)
 	  {
 	    li = ignore_suffix->next;
-	    free(ignore_suffix->suffix);
+	    free(ignore_suffix->name);
 	    free(ignore_suffix);
 	  }
 	for(; match_suffix; match_suffix = li)
 	  {
 	    li = match_suffix->next;
-	    free(match_suffix->suffix);
+	    free(match_suffix->name);
 	    free(match_suffix);
 	  }
+	for(; files; files = li)
+	  {
+	    li = files->next;
+	    free(files->name);
+	    free(files);
+	  }
 	break;
       }