eal: support strlcat function

Add the strlcat function to DPDK to exist alongside the strlcpy one.
While strncat is generally safe for use for concatenation, the API for the
strlcat function is perhaps a little nicer to use, and supports truncation
detection.

See commit 5364de644a4b ("eal: support strlcpy function") for more
details on the function selection logic, since we only should be using the
DPDK-provided version when no system-provided version is present.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

diff --git a/lib/librte_eal/common/include/rte_string_fns.h b/lib/librte_eal/common/include/rte_string_fns.h
index 9a2a1ff..35c6b00 100644 (file)
--- a/lib/librte_eal/common/include/rte_string_fns.h
+++ b/lib/librte_eal/common/include/rte_string_fns.h
@@ -59,10 +59,25 @@ rte_strlcpy(char *dst, const char *src, size_t size)
        return (size_t)snprintf(dst, size, "%s", src);
 }
 
+/**
+ * @internal
+ * DPDK-specific version of strlcat for systems without
+ * libc or libbsd copies of the function
+ */
+static inline size_t
+rte_strlcat(char *dst, const char *src, size_t size)
+{
+       size_t l = strnlen(dst, size);
+       if (l < size)
+               return l + rte_strlcpy(&dst[l], src, size - l);
+       return l + strlen(src);
+}
+
 /* pull in a strlcpy function */
 #ifdef RTE_EXEC_ENV_BSDAPP
 #ifndef __BSD_VISIBLE /* non-standard functions are hidden */
 #define strlcpy(dst, src, size) rte_strlcpy(dst, src, size)
+#define strlcat(dst, src, size) rte_strlcat(dst, src, size)
 #endif
 
 #else /* non-BSD platforms */
@@ -71,6 +86,7 @@ rte_strlcpy(char *dst, const char *src, size_t size)
 
 #else /* no BSD header files, create own */
 #define strlcpy(dst, src, size) rte_strlcpy(dst, src, size)
+#define strlcat(dst, src, size) rte_strlcat(dst, src, size)
 
 #endif /* RTE_USE_LIBBSD */
 #endif /* BSDAPP */

diff --git a/test/test/test_string_fns.c b/test/test/test_string_fns.c
index 3f091ab..5e105d2 100644 (file)
--- a/test/test/test_string_fns.c
+++ b/test/test/test_string_fns.c
@@ -129,11 +129,56 @@ test_rte_strsplit(void)
        return 0;
 }
 
+static int
+test_rte_strlcat(void)
+{
+       /* only run actual unit tests if we have system-provided strlcat */
+#if defined(__BSD_VISIBLE) || defined(RTE_USE_LIBBSD)
+#define BUF_LEN 32
+       const char dst[BUF_LEN] = "Test string";
+       const char src[] = " appended";
+       char bsd_dst[BUF_LEN];
+       char rte_dst[BUF_LEN];
+       size_t i, bsd_ret, rte_ret;
+
+       LOG("dst = '%s', strlen(dst) = %zu\n", dst, strlen(dst));
+       LOG("src = '%s', strlen(src) = %zu\n", src, strlen(src));
+       LOG("---\n");
+
+       for (i = 0; i < BUF_LEN; i++) {
+               /* initialize destination buffers */
+               memcpy(bsd_dst, dst, BUF_LEN);
+               memcpy(rte_dst, dst, BUF_LEN);
+               /* compare implementations */
+               bsd_ret = strlcat(bsd_dst, src, i);
+               rte_ret = rte_strlcat(rte_dst, src, i);
+               if (bsd_ret != rte_ret) {
+                       LOG("Incorrect retval for buf length = %zu\n", i);
+                       LOG("BSD: '%zu', rte: '%zu'\n", bsd_ret, rte_ret);
+                       return -1;
+               }
+               if (memcmp(bsd_dst, rte_dst, BUF_LEN) != 0) {
+                       LOG("Resulting buffers don't match\n");
+                       LOG("BSD: '%s', rte: '%s'\n", bsd_dst, rte_dst);
+                       return -1;
+               }
+               LOG("buffer size = %zu: dst = '%s', ret = %zu\n",
+                       i, rte_dst, rte_ret);
+       }
+       LOG("Checked %zu combinations\n", i);
+#undef BUF_LEN
+#endif /* defined(__BSD_VISIBLE) || defined(RTE_USE_LIBBSD) */
+
+       return 0;
+}
+
 static int
 test_string_fns(void)
 {
        if (test_rte_strsplit() < 0)
                return -1;
+       if (test_rte_strlcat() < 0)
+               return -1;
        return 0;
 }