There's an ongoing project to bring some kind of path selection

mechanism to the ENGINE framework.  This means there there are going
to be new functionality for the DSO part, and ultimately some way of
merging two file specifications together.

This commit places the merging code into the repository.  It's
currently not used anywhere, and hasn't been tested at all.  It may be
full of errors, including syntactical ones.  Those will be fixed as
promptly as possible.

1 files changed, 69 insertions, 1 deletions

diff --git a/crypto/dso/dso_dl.c b/crypto/dso/dso_dl.c
index 195717e993..32a8d41bf7 100644
--- a/crypto/dso/dso_dl.c
+++ b/crypto/dso/dso_dl.c
@@ -1,4 +1,4 @@
-/* dso_dl.c */
+/* dso_dl.c -*- mode:C; c-file-style: "eay" -*- */
 /* Written by Richard Levitte (richard@levitte.org) for the OpenSSL
  * project 2000.
  */
@@ -84,6 +84,7 @@ static int dl_finish(DSO *dso);
 static int dl_ctrl(DSO *dso, int cmd, long larg, void *parg);
 #endif
 static char *dl_name_converter(DSO *dso, const char *filename);
+static char *dl_merger(DSO *dso, const char *filespec1, const char *filespec2);
 
 static DSO_METHOD dso_meth_dl = {
 	"OpenSSL 'dl' shared library method",
@@ -98,6 +99,7 @@ static DSO_METHOD dso_meth_dl = {
 #endif
 	NULL, /* ctrl */
 	dl_name_converter,
+	dl_merger,
 	NULL, /* init */
 	NULL  /* finish */
 	};
@@ -238,6 +240,72 @@ static DSO_FUNC_TYPE dl_bind_func(DSO *dso, const char *symname)
 	return((DSO_FUNC_TYPE)sym);
 	}
 
+static char *dl_merger(DSO *dso, const char *filespec1, const char *filespec2)
+	{
+	char *merged;
+
+	if(!filespec1 && !filespec2)
+		{
+		DSOerr(DSO_F_DL_MERGER,
+				ERR_R_PASSED_NULL_PARAMETER);
+		return(NULL);
+		}
+	/* If the first file specification is a rooted path, it rules.
+	   same goes if the second file specification is missing. */
+	if (!filespec2 || filespec1[0] == '/')
+		{
+		merged = OPENSSL_malloc(strlen(filespec1) + 1);
+		if(!merged)
+			{
+			DSOerr(DSO_F_DL_MERGER,
+				ERR_R_MALLOC_FAILURE);
+			return(NULL);
+			}
+		strcpy(merged, filespec1);
+		}
+	/* If the first file specification is missing, the second one rules. */
+	else if (!filespec1)
+		{
+		merged = OPENSSL_malloc(strlen(filespec2) + 1);
+		if(!merged)
+			{
+			DSOerr(DSO_F_DL_MERGER,
+				ERR_R_MALLOC_FAILURE);
+			return(NULL);
+			}
+		strcpy(merged, filespec2);
+		}
+	else
+		/* This part isn't as trivial as it looks.  It assumes that
+		   the second file specification really is a directory, and
+		   makes no checks whatsoever.  Therefore, the result becomes
+		   the concatenation of filespec2 followed by a slash followed
+		   by filespec1. */
+		{
+		int spec2len, len;
+
+		spec2len = (filespec2 ? strlen(filespec2) : 0);
+		len = spec2len + (filespec1 ? strlen(filespec1) : 0);
+
+		if(filespec2 && filespec2[spec2len - 1] == '/')
+			{
+			spec2len--;
+			len--;
+			}
+		merged = OPENSSL_malloc(len + 2);
+		if(!merged)
+			{
+			DSOerr(DSO_F_DL_MERGER,
+				ERR_R_MALLOC_FAILURE);
+			return(NULL);
+			}
+		strcpy(merged, filespec2);
+		merged[spec2len] = '/';
+		strcpy(&merged[spec2len + 1], filespec1);
+		}
+	return(merged);
+	}
+
 /* This function is identical to the one in dso_dlfcn.c, but as it is highly
  * unlikely that both the "dl" *and* "dlfcn" variants are being compiled at the
  * same time, there's no great duplicating the code. Figuring out an elegant