Add string copy and catonate replacements

* safe_strncpy
* safe_strncat

2 files changed, 22 insertions, 0 deletions

diff --git a/src/lib/core/include/str.h b/src/lib/core/include/str.h
index 3e7c3a4..2f86242 100644
--- a/src/lib/core/include/str.h
+++ b/src/lib/core/include/str.h
@@ -324,4 +324,7 @@ char *to_short_version(const char *s);
 
 void unindent(char *s);
 
+int safe_strncpy(char *dst, const char *src, size_t dsize);
+int safe_strncat(char *dst, const char *src, size_t dsize);
+
 #endif //STASIS_STR_H
diff --git a/src/lib/core/str.c b/src/lib/core/str.c
index c31ce5e..02c6722 100644
--- a/src/lib/core/str.c
+++ b/src/lib/core/str.c
@@ -750,3 +750,22 @@ char *remove_extras(char *s) {
     return s;
 }
 
+int safe_strncpy(char *dst, const char *src, const size_t dsize) {
+    return snprintf(dst, dsize, "%s", src);
+}
+
+int safe_strncat(char *dst, const char *src, const size_t dsize) {
+    const size_t used = strnlen(dst, dsize);
+    if (used == dsize) {
+        SYSERROR("destination is not NUL terminated: %p", dst);
+        return -1;
+    }
+    const size_t maxlen = dsize - used;
+    const int len = snprintf(dst + strlen(dst), maxlen, "%s", src);
+    if (len < 0) {
+        SYSERROR("encoding error");
+    } else if ((size_t) len >= maxlen) {
+        SYSWARN("destination truncated: %p", dst);
+    }
+    return len;
+}
\ No newline at end of file