Implement lttng_strncpy safe string copy

[lttng-tools.git] / src / common / macros.h

diff --git a/src/common/macros.h b/src/common/macros.h
index 8185c85abfdacdece8bd4442cc10ca2898b8bd32..9304388554d0af82e61ab6ae2e0abddca933960d 100644 (file)
--- a/src/common/macros.h
+++ b/src/common/macros.h
@@ -20,6 +20,7 @@
 #define _MACROS_H
 
 #include <stdlib.h>
+#include <string.h>
 
 /*
  * Takes a pointer x and transform it so we can use it to access members
@@ -46,10 +47,58 @@
 /*
  * Memory allocation zeroed
  */
-#define zmalloc(x) calloc(1, x)
+static inline
+void *zmalloc(size_t len)
+{
+       return calloc(1, len);
+}
 
 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
 #endif
 
+#ifndef max
+#define max(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
+#ifndef max_t
+#define max_t(type, a, b)      ((type) max(a, b))
+#endif
+
+#ifndef min
+#define min(a, b) ((a) < (b) ? (a) : (b))
+#endif
+
+#ifndef LTTNG_PACKED
+#define LTTNG_PACKED __attribute__((__packed__))
+#endif
+
+#ifndef LTTNG_HIDDEN
+#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
+#endif
+
+/*
+ * lttng_strncpy returns 0 on success, or nonzero on failure.
+ * It checks that the @src string fits into @dst_len before performing
+ * the copy. On failure, no copy has been performed.
+ *
+ * dst_len includes the string's trailing NULL.
+ */
+static inline
+int lttng_strncpy(char *dst, const char *src, size_t dst_len)
+{
+       if (strnlen(src, dst_len) == dst_len) {
+               /* Fail since copying would result in truncation. */
+               return -1;
+       }
+       strncpy(dst, src, dst_len);
+       /*
+        * Be extra careful and put final \0 at the end after strncpy(),
+        * even though we checked the length before. This makes Coverity
+        * happy.
+        */
+       dst[dst_len - 1] = '\0';
+       return 0;
+}
+
 #endif /* _MACROS_H */