[dpdk-dev,1/2] add support for strlcpy function
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Commit Message
The strncpy function is error prone for doing "safe" string copies, so
we generally try to use "snprintf" instead in the code. The function
"strlcpy" is a better alternative, since it better conveys the
intention of the programmer, and doesn't suffer from the non-null
terminating behaviour of it's n'ed brethern.
The downside of this function is that it is not available by default
on linux, though standard in the BSD's. It is available on most
distros by installing "libbsd" package.
This patch therefore provides the following in rte_string_fns.h to ensure
that strlcpy is available there:
* for BSD, include string.h as normal
* if RTE_USE_LIBBSD is set, include <bsd/string.h>
* if not set, fallback to snprintf for strlcpy
Using make build system, the RTE_USE_LIBBSD is a hard-coded value to "n",
but when using meson, it's automatically set based on what is available
on the platform.
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
----
RFC->v1:
* split patch into 2, to separate out snprintf replacement
* added missing include in mlx drivers
* adding linking support against libbsd when feature is enabled
* make strlcpy an inline function rather than macro
* fix support on BSD where strict posix compliance is requested and
therefore strlcpy is not available.
---
config/common_base | 1 +
config/meson.build | 7 +++++++
devtools/cocci/strlcpy.cocci | 8 +++++++
lib/librte_eal/common/include/rte_string_fns.h | 29 ++++++++++++++++++++++++++
mk/rte.app.mk | 3 +++
5 files changed, 48 insertions(+)
create mode 100644 devtools/cocci/strlcpy.cocci
Comments
On Mon, Mar 12, 2018 at 11:32:59AM +0000, Bruce Richardson wrote:
> The strncpy function is error prone for doing "safe" string copies, so
> we generally try to use "snprintf" instead in the code. The function
> "strlcpy" is a better alternative, since it better conveys the
> intention of the programmer, and doesn't suffer from the non-null
> terminating behaviour of it's n'ed brethern.
>
> The downside of this function is that it is not available by default
> on linux, though standard in the BSD's. It is available on most
> distros by installing "libbsd" package.
>
> This patch therefore provides the following in rte_string_fns.h to ensure
> that strlcpy is available there:
> * for BSD, include string.h as normal
> * if RTE_USE_LIBBSD is set, include <bsd/string.h>
> * if not set, fallback to snprintf for strlcpy
>
> Using make build system, the RTE_USE_LIBBSD is a hard-coded value to "n",
> but when using meson, it's automatically set based on what is available
> on the platform.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
>
> ----
> RFC->v1:
> * split patch into 2, to separate out snprintf replacement
> * added missing include in mlx drivers
> * adding linking support against libbsd when feature is enabled
> * make strlcpy an inline function rather than macro
> * fix support on BSD where strict posix compliance is requested and
> therefore strlcpy is not available.
> ---
Forgot to include Stephen's reviewed-by from RFC:
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
@@ -76,6 +76,7 @@ CONFIG_RTE_EAL_VFIO=n
CONFIG_RTE_MAX_VFIO_GROUPS=64
CONFIG_RTE_MALLOC_DEBUG=n
CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES=n
+CONFIG_RTE_USE_LIBBSD=n
#
# Recognize/ignore the AVX/AVX512 CPU flags for performance/power testing.
@@ -38,6 +38,13 @@ if numa_dep.found() and cc.has_header('numaif.h')
dpdk_extra_ldflags += '-lnuma'
endif
+# check for strlcpy
+if host_machine.system() == 'linux' and cc.find_library('bsd', required: false).found()
+ dpdk_conf.set('RTE_USE_LIBBSD', 1)
+ add_project_link_arguments('-lbsd', language: 'c')
+ dpdk_extra_ldflags += '-lbsd'
+endif
+
# add -include rte_config to cflags
add_project_arguments('-include', 'rte_config.h', language: 'c')
new file mode 100644
@@ -0,0 +1,8 @@
+@use_strlcpy@
+identifier src, dst;
+expression size;
+@@
+(
+- snprintf(dst, size, "%s", src)
++ strlcpy(dst, src, size)
+)
@@ -45,6 +45,35 @@ int
rte_strsplit(char *string, int stringlen,
char **tokens, int maxtokens, char delim);
+/**
+ * @internal
+ * DPDK-specific version of strlcpy for systems without
+ * libc or libbsd copies of the function
+ */
+static inline size_t
+rte_strlcpy(char *dst, const char *src, size_t size)
+{
+ return snprintf(dst, size, "%s", src);
+}
+
+/* pull in a strlcpy function */
+#ifdef RTE_EXEC_ENV_BSDAPP
+#include <string.h>
+#ifndef __BSD_VISIBLE /* non-standard functions are hidden */
+#define strlcpy(dst, src, size) rte_strlcpy(dst, src, size)
+#endif
+
+
+#else /* non-BSD platforms */
+#ifdef RTE_USE_LIBBSD
+#include <bsd/string.h>
+
+#else /* no BSD header files, create own */
+#define strlcpy(dst, src, size) rte_strlcpy(dst, src, size)
+
+#endif /* RTE_USE_LIBBSD */
+#endif /* BSDAPP */
+
#ifdef __cplusplus
}
#endif
@@ -248,6 +248,9 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_EAL) += -lrt
ifeq ($(CONFIG_RTE_EXEC_ENV_LINUXAPP)$(CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES),yy)
_LDLIBS-$(CONFIG_RTE_LIBRTE_EAL) += -lnuma
endif
+ifeq ($(CONFIG_RTE_EXEC_ENV_LINUXAPP)$(CONFIG_RTE_USE_LIBBSD),yy)
+_LDLIBS-$(CONFIG_RTE_LIBRTE_EAL) += -lbsd
+endif
_LDLIBS-$(CONFIG_RTE_LIBRTE_SCHED) += -lm
_LDLIBS-$(CONFIG_RTE_LIBRTE_SCHED) += -lrt
_LDLIBS-$(CONFIG_RTE_LIBRTE_MEMBER) += -lm