add various escaping/path handling utility functions

A portion of systemd commit 4fe88d28a4cfa504c1f2362d4a7030fae4c4af29 , needed to
support changes made by commit 6284c1ca41dca85e968e8d304cdc154c5a46d6d2

Signed-off-by: Ian Stakenvicius <axs@gentoo.org>

2 files changed, 30 insertions, 0 deletions

diff --git a/src/libudev/util.c b/src/libudev/util.c
index f625cfe99b..8fec6856e0 100644
--- a/src/libudev/util.c
+++ b/src/libudev/util.c
@@ -1046,3 +1046,31 @@ void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
         return NULL;
 }
 
+char *xescape(const char *s, const char *bad) {
+        char *r, *t;
+        const char *f;
+
+        /* Escapes all chars in bad, in addition to \ and all special
+         * chars, in \xFF style escaping. May be reversed with
+         * cunescape. */
+
+        if (!(r = new(char, strlen(s)*4+1)))
+                return NULL;
+
+        for (f = s, t = r; *f; f++) {
+
+                if (*f < ' ' || *f >= 127 ||
+                    *f == '\\' || strchr(bad, *f)) {
+                        *(t++) = '\\';
+                        *(t++) = 'x';
+                        *(t++) = hexchar(*f >> 4);
+                        *(t++) = hexchar(*f);
+                } else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+
+        return r;
+}
+
diff --git a/src/libudev/util.h b/src/libudev/util.h
index 60b300da3c..96a42bf3d3 100644
--- a/src/libudev/util.h
+++ b/src/libudev/util.h
@@ -272,6 +272,8 @@ void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
                  int (*compar) (const void *, const void *, void *),
                  void *arg);
 
+char *xescape(const char *s, const char *bad);
+
 static inline void _reset_errno_(int *saved_errno) {
         errno = *saved_errno;
 }