libdpkg: Move quote_filename to the path module as path_quote_filename

This function will be useful for other parts of dpkg, so the function
has been moved to a more sensible location, the static qualifier removed,
and its name appropriately prefixed.

Signed-off-by: Guillem Jover <guillem@debian.org>

2 files changed, 62 insertions, 0 deletions

diff --git a/lib/dpkg/path.c b/lib/dpkg/path.c
index 8ea891eb4..240bdce4d 100644
--- a/lib/dpkg/path.c
+++ b/lib/dpkg/path.c
@@ -23,6 +23,7 @@
 #include <config.h>
 #include <compat.h>
 
+#include <stdio.h>
 #include <string.h>
 
 #include <dpkg/path.h>
@@ -54,3 +55,63 @@ path_skip_slash_dotslash(const char *path)
 	return path;
 }
 
+/*
+ * snprintf(3) doesn't work if format contains %.<nnn>s and an argument has
+ * invalid char for locale, then it returns -1.
+ * ohshite() is ok, but fd_fd_copy(), which is used in tarobject() in this
+ * file, is not ok, because
+ * - fd_fd_copy() == buffer_copy_setup() [include/dpkg.h]
+ * - buffer_copy_setup() uses varbufvprintf(&v, desc, al); [lib/mlib.c]
+ * - varbufvprintf() fails and memory exausted, because it call
+ *    fmt = "backend dpkg-deb during `%.255s'
+ *    arg may contain some invalid char, for example,
+ *    /usr/share/doc/console-tools/examples/unicode/\342\231\252\342\231\254
+ *   in console-tools.
+ *   In this case, if user uses some locale which doesn't support \342\231...,
+ *   vsnprintf() always returns -1 and varbufextend() get called again
+ *   and again until memory is exausted and it aborts.
+ *
+ * So, we need to escape invalid char, probably as in
+ * tar-1.13.19/lib/quotearg.c: quotearg_buffer_restyled()
+ * but here I escape all 8bit chars, in order to be simple.
+ * - ukai@debian.or.jp
+ */
+char *
+path_quote_filename(char *buf, int size, char *s)
+{
+	char *r = buf;
+
+	while (size > 0) {
+		switch (*s) {
+		case '\0':
+			*buf = '\0';
+			return r;
+		case '\\':
+			*buf++ = '\\';
+			*buf++ = '\\';
+			size -= 2;
+			break;
+		default:
+			if (((*s) & 0x80) == '\0') {
+				*buf++ = *s++;
+				--size;
+			} else {
+				if (size > 4) {
+					sprintf(buf, "\\%03o",
+					        *(unsigned char *)s);
+					size -= 4;
+					buf += 4;
+					s++;
+				} else {
+					/* Buffer full. */
+					*buf = '\0'; /* XXX */
+					return r;
+				}
+			}
+		}
+	}
+	*buf = '\0'; /* XXX */
+
+	return r;
+}
+
diff --git a/lib/dpkg/path.h b/lib/dpkg/path.h
index 701eb8e87..ae65f063e 100644
--- a/lib/dpkg/path.h
+++ b/lib/dpkg/path.h
@@ -32,6 +32,7 @@ DPKG_BEGIN_DECLS
 
 size_t path_rtrim_slash_slashdot(char *path);
 const char *path_skip_slash_dotslash(const char *path);
+char *path_quote_filename(char *buf, int size, char *s);
 
 DPKG_END_DECLS