search path: lt_dl{add|insert|set|get}searchdir(): initial implementation.

1 files changed, 242 insertions, 0 deletions

diff --git a/src/core/lt_path.c b/src/core/lt_path.c
new file mode 100644
index 0000000..14eb0eb
--- /dev/null
+++ b/src/core/lt_path.c
@@ -0,0 +1,242 @@
+/*******************************************************************/
+/*  sltdl: a surrogate ltdl implementation                         */
+/*  Copyright (C) 2019 Z. Gilboa                                   */
+/*  Released under the Standard MIT License; see COPYING.SLTDL.    */
+/*******************************************************************/
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include <sltdl/sltdl.h>
+#include "sltdl_core.h"
+
+static off_t   lt_plen;
+static off_t   lt_plocs;
+static char *  lt_upath;
+static char *  lt_vpath;
+static char ** lt_vmark;
+static char ** lt_pathv;
+
+const char * lt_dlgetsearchpath(void)
+{
+	return lt_upath;
+}
+
+static int lt_dlsetsearchpath_locked(const char * path)
+{
+	const char *    ch;
+	char *          uch;
+	char *          vch;
+	char **         pathv;
+	off_t           elements;
+
+	if (path[0] != '/')
+		return 1;
+
+	elements = 1;
+
+	for (ch=&path[1]; *ch; ch++) {
+		if (*ch == ':') {
+			if (ch[1] != '/')
+				return 1;
+
+			elements++;
+		}
+	}
+
+	if (++elements > lt_plocs) {
+		if (lt_pathv) {
+			free(lt_pathv);
+			lt_pathv = 0;
+		}
+
+		lt_plocs  = elements;
+		lt_plocs += 0x3f;
+		lt_plocs |= 0x3f;
+		lt_plocs ^= 0x3f;
+
+		if (!(lt_pathv = calloc(lt_plocs,sizeof(char *))))
+			return 1;
+	}
+
+	if ((ch - path) > lt_plen) {
+		if (lt_upath) {
+			free(lt_upath);
+			lt_upath = 0;
+		}
+
+		lt_plen = ((ch - path + 1) <= 0x800)
+			? 0x800 : ch - path + 1;
+
+		lt_plen += 0x7ff;
+		lt_plen |= 0x7ff;
+		lt_plen ^= 0x7ff;
+
+		if (!(lt_upath = calloc(2*lt_plen,1)))
+			return 1;
+
+		lt_vpath = &lt_upath[lt_plen];
+	}
+
+	pathv    = lt_pathv;
+	*pathv++ = lt_vpath;
+
+	for (ch=path, uch=lt_upath, vch=lt_vpath; *ch; ch++) {
+		if (*ch == ':') {
+			*uch++ = ch[0];
+			*uch++ = ch[1];
+
+			*vch++ = 0;
+			*pathv = vch;
+			*vch++ = ch[1];
+
+			ch++;
+			pathv++;
+		} else {
+			*uch++ = *ch;
+			*vch++ = *ch;
+		}
+	}
+
+	lt_vmark = pathv;
+
+	return 0;
+}
+
+int lt_dlsetsearchpath(const char * path)
+{
+	lt_slock();
+	return lt_sunlock(lt_dlsetsearchpath_locked(path));
+}
+
+int lt_dladdsearchdir(const char * path)
+{
+	int          ret;
+	const char * ch;
+	char *       buf;
+	off_t        alen;
+	off_t        plen;
+
+	if (path[0] != '/')
+		return 1;
+
+	for (ch=path; *ch; ch++)
+		if (*ch == ':')
+			return 1;
+
+	lt_slock();
+
+	alen = strlen(path);
+	plen = strlen(lt_upath);
+
+	/* no allocation needed? */
+	if (!lt_pathv[lt_plocs - 2] && ((plen + 1 + alen + 1) <= lt_plen)) {
+		lt_upath[plen] = ':';
+		lt_vpath[plen] = 0;
+
+		plen++;
+
+		strcpy(&lt_upath[plen],path);
+		strcpy(&lt_vpath[plen],path);
+
+		*lt_vmark++ = &lt_vpath[plen];
+
+		return lt_sunlock(0);
+	}
+
+	/* (allocation needed) */
+	if (!(buf = malloc(plen + 1 + alen + 1)))
+		return lt_sunlock(1);
+
+	sprintf(buf,"%s:%s",lt_upath,path);
+
+	ret = lt_dlsetsearchpath_locked(buf);
+
+	free(buf);
+
+	return lt_sunlock(ret);
+}
+
+int lt_dlinsertsearchdir(const char * mark, const char * path)
+{
+	int          ret;
+	const char * ch;
+	char *       buf;
+	char *       dst;
+	off_t        alen;
+	off_t        plen;
+	off_t        slen;
+	off_t        offset;
+	char **      pathv;
+
+	if (path[0] != '/')
+		return 1;
+
+	if (!mark)
+		return lt_dladdsearchdir(path);
+
+	for (ch=path; *ch; ch++)
+		if (*ch == ':')
+			return 1;
+
+	lt_slock();
+
+	alen = strlen(path);
+	plen = strlen(lt_upath);
+
+	if ((mark < lt_upath) || (mark >= &lt_upath[plen]))
+		return lt_sunlock(1);
+
+	if ((mark > lt_upath) && (mark[-1] != ':'))
+		return lt_sunlock(1);
+
+	mark = &lt_vpath[mark - lt_upath];
+
+	/* no allocation needed? */
+	if (!lt_pathv[lt_plocs - 2] && ((plen + 1 + alen + 1) <= lt_plen)) {
+		for (pathv=lt_vmark; pathv>=lt_pathv; pathv--) {
+			slen    = strlen(pathv[-1]);
+			offset  = pathv[-1] - lt_vpath;
+			offset += alen + 1;
+
+			memcpy(&lt_upath[offset],pathv[-1],slen);
+			memcpy(&lt_vpath[offset],&lt_upath[offset],slen);
+
+			if (pathv < lt_vmark)
+				lt_upath[offset + slen] = ':';
+
+			pathv[0] = pathv[-1];
+
+			if (pathv[-1] == mark) {
+				offset = mark - lt_vpath;
+				strcpy(&lt_vpath[offset],path);
+				memcpy(&lt_upath[offset],path,alen);
+				lt_upath[offset+alen] = ':';
+				lt_vmark++;
+				return lt_sunlock(0);
+			}
+		}
+	}
+
+	/* (allocation needed) */
+	if (!(buf = malloc(plen + 1 + alen + 1)))
+		return lt_sunlock(1);
+
+	for (dst=buf, pathv=lt_pathv; *pathv; pathv++) {
+		if (*pathv == mark)
+			dst += sprintf(dst,"%s:",path);
+
+		if (pathv[1])
+			dst += sprintf(dst,"%s:",*pathv);
+		else
+			dst += sprintf(dst,"%s",*pathv);
+	}
+
+	ret = lt_dlsetsearchpath_locked(buf);
+
+	free(buf);
+
+	return lt_sunlock(ret);
+}