From 49d0b265b2a1e49eac871a2e4d45aa59d8a4bf47 Mon Sep 17 00:00:00 2001
From: rofl0r <rofl0r@users.noreply.github.com>
Date: Fri, 7 Jun 2024 23:32:27 +0000
Subject: [PATCH] add normalizepath_cstr()

---
 include/filelib.h                |   9 +++-
 src/filelib/normalizepath_cstr.c | 111 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 src/filelib/normalizepath_cstr.c

diff --git a/include/filelib.h b/include/filelib.h
index 6a94ec5..536d31d 100644
--- a/include/filelib.h
+++ b/include/filelib.h
@@ -9,11 +9,18 @@
 char* getFileExt(const char* filename, size_t fnlen);
 time_t getFileModTime(const char* filename);
 size_t getfilesize(char* filename);
-int normalizepath(stringptr* path);
 ssize_t getpathdiff(stringptr* path1, stringptr* path2, char* workbuf);
 char* ulz_mkdtemp(char* templ);
 size_t mktempdir(const char* prefix, char* buffer, size_t bufsize);
 char* getfilename(stringptr* path);
+int normalizepath(stringptr* path);
+/* removes multiple slashes, /./ style stuff and resolves ../ kind of stuff on _absolute_ paths.
+ * will always strip trailing slashes.
+ * will fail with relative paths. does not resolve symlinks.
+ * out must point to a buffer of sufficient size, which equals (worst case) strlen(path)+1.
+ * returns 0 on failure, on success out.
+*/
+char* normalizepath_cstr(const char* path, char* out);
 
 #pragma RcB2 DEP "../src/filelib/*.c"
 
diff --git a/src/filelib/normalizepath_cstr.c b/src/filelib/normalizepath_cstr.c
new file mode 100644
index 0000000..74276bf
--- /dev/null
+++ b/src/filelib/normalizepath_cstr.c
@@ -0,0 +1,111 @@
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#include <stddef.h>
+#include <string.h>
+
+/* removes multiple slashes, /./ style stuff and resolves ../ kind of stuff on _absolute_ paths.
+ * will always strip trailing slashes.
+ * will fail with relative paths. does not resolve symlinks.
+ * out must point to a buffer of sufficient size, which equals (worst case) strlen(path)+1.
+ * returns 0 on failure, on success out.
+*/
+char* normalizepath_cstr(const char* path, char* out) {
+	size_t i, out_size = 0;
+	char* tmp;
+#if defined(__psp__) || defined(PSPLIKE_PATH)
+	/* psp paths are a mix of DOS and unix, with a drive name + colon,
+	   followed by a unix path, e.g. ms0:/PSP */
+	for(i = 0; path[i]; ++i) {
+		out[out_size++] = path[i];
+		if(path[i] == '/') {
+			--out_size;
+			if(i > 0 && path[i-1] != ':') goto fail;
+			break;
+		}
+	}
+#else
+	i = 0;
+#endif
+	if(path[i] != '/') goto fail;
+	for(; path[i]; i++) {
+		switch(path[i]) {
+		case '/':
+			while(path[i+1] == '/') i++;
+			if(!out_size || out[out_size -1] != '/') goto copy;
+			break;
+		case '.':
+			if(!i || !out_size) goto fail;
+			else if(path[i-1] == '/' && out[out_size -1] == '/') {
+				out_size--;
+				switch(path[i+1]) {
+					case '.':
+						if((!path[i+2] || path[i+2] == '/')) {
+							tmp = out + out_size;
+							while(--tmp > out && *tmp != '/');
+							if(tmp >= out && *tmp == '/') {
+								out_size = tmp - out;
+								i += 2;
+								goto restore;
+							} else {
+								fail:
+								return 0;
+							}
+						}
+						goto def;
+					case '/':
+						i++;
+						restore:
+						out_size++;
+						if(!path[i]) goto done;
+						break;
+					case 0:
+						goto restore;
+					default:
+						def:
+						out_size++;
+						goto copy;
+						break;
+				}
+			} else goto copy;
+			break;
+		default:
+			copy:
+			out[out_size++] = path[i];
+			break;
+		}
+	}
+	done:
+	if(out_size > 1 && out[out_size -1] == '/')
+		out_size--; // remove trailing slash
+	out[out_size] = 0;
+	return out;
+}
+
+#ifdef FUZZER_TEST
+#include <sys/mman.h>
+#include <stdio.h>
+int main(int a, char**b) {
+	char buf[64], wb[64];
+	if(a == 3 && b[1][0] == 'X' && !b[1][1]) {
+		if(normalizepath_cstr(b[2], buf))
+			printf("%s -> %s\n" , b[2], buf);
+		return 0;
+	}
+	FILE *f;
+	if(a == 2 && (f = fopen(b[1], "r")) && fgets(buf, sizeof buf, f)) {
+		size_t l = strlen(buf); if(l) buf[l-1] = 0; else return 1;
+		char *page2 = mmap(0, 4096, PROT_NONE,MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+		char* page = mmap(0, 4096, PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+		if(!page) return 1;
+		if(!page2) return 1;
+		if(page2-page!=4096) return 1;
+		char* ns = page+4096-l;
+		memcpy(ns, buf, l);
+		if (normalizepath_cstr(ns, wb))
+			printf("%s -> %s\n" , ns, wb);
+		fclose(f);
+		return 0;
+	}
+	return 1;
+}
+#endif
-- 
2.11.4.GIT