[dpdk-dev] [PATCH v4 2/8] eal: introduce internal wrappers for file operations
Dmitry Kozlyuk
dmitry.kozliuk at gmail.com
Wed Apr 29 01:50:09 CEST 2020
EAL common code uses file locking and truncation. Introduce
OS-independent wrappers in order to support both Linux/FreeBSD
and Windows:
* eal_file_lock: lock or unlock an open file.
* eal_file_truncate: enforce a given size for an open file.
Wrappers follow POSIX semantics, but interface is not POSIX,
so that it can be made more clean, e.g. by not mixing locking
operation and behaviour on conflict.
Implementation for Linux and FreeBSD is placed in "unix" subdirectory,
which is intended for common code between the two. Files should be named
after the ones from which the code is factored in OS subdirectory.
Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk at gmail.com>
---
lib/librte_eal/common/eal_common_fbarray.c | 19 ++++----
lib/librte_eal/common/eal_private.h | 45 +++++++++++++++++++
lib/librte_eal/freebsd/Makefile | 4 ++
lib/librte_eal/linux/Makefile | 4 ++
lib/librte_eal/meson.build | 4 ++
lib/librte_eal/unix/eal_unix.c | 51 ++++++++++++++++++++++
lib/librte_eal/unix/meson.build | 6 +++
7 files changed, 122 insertions(+), 11 deletions(-)
create mode 100644 lib/librte_eal/unix/eal_unix.c
create mode 100644 lib/librte_eal/unix/meson.build
diff --git a/lib/librte_eal/common/eal_common_fbarray.c b/lib/librte_eal/common/eal_common_fbarray.c
index 4f8f1af73..1e55757ca 100644
--- a/lib/librte_eal/common/eal_common_fbarray.c
+++ b/lib/librte_eal/common/eal_common_fbarray.c
@@ -8,8 +8,8 @@
#include <sys/mman.h>
#include <stdint.h>
#include <errno.h>
-#include <sys/file.h>
#include <string.h>
+#include <unistd.h>
#include <rte_common.h>
#include <rte_log.h>
@@ -85,7 +85,7 @@ resize_and_map(int fd, void *addr, size_t len)
char path[PATH_MAX];
void *map_addr;
- if (ftruncate(fd, len)) {
+ if (eal_file_truncate(fd, len)) {
RTE_LOG(ERR, EAL, "Cannot truncate %s\n", path);
/* pass errno up the chain */
rte_errno = errno;
@@ -778,7 +778,8 @@ rte_fbarray_init(struct rte_fbarray *arr, const char *name, unsigned int len,
__func__, path, strerror(errno));
rte_errno = errno;
goto fail;
- } else if (flock(fd, LOCK_EX | LOCK_NB)) {
+ } else if (eal_file_lock(
+ fd, EAL_FLOCK_EXCLUSIVE, EAL_FLOCK_RETURN)) {
RTE_LOG(DEBUG, EAL, "%s(): couldn't lock %s: %s\n",
__func__, path, strerror(errno));
rte_errno = EBUSY;
@@ -789,10 +790,8 @@ rte_fbarray_init(struct rte_fbarray *arr, const char *name, unsigned int len,
* still attach to it, but no other process could reinitialize
* it.
*/
- if (flock(fd, LOCK_SH | LOCK_NB)) {
- rte_errno = errno;
+ if (eal_file_lock(fd, EAL_FLOCK_SHARED, EAL_FLOCK_RETURN))
goto fail;
- }
if (resize_and_map(fd, data, mmap_len))
goto fail;
@@ -895,10 +894,8 @@ rte_fbarray_attach(struct rte_fbarray *arr)
}
/* lock the file, to let others know we're using it */
- if (flock(fd, LOCK_SH | LOCK_NB)) {
- rte_errno = errno;
+ if (eal_file_lock(fd, EAL_FLOCK_SHARED, EAL_FLOCK_RETURN))
goto fail;
- }
if (resize_and_map(fd, data, mmap_len))
goto fail;
@@ -1025,7 +1022,7 @@ rte_fbarray_destroy(struct rte_fbarray *arr)
* has been detached by all other processes
*/
fd = tmp->fd;
- if (flock(fd, LOCK_EX | LOCK_NB)) {
+ if (eal_file_lock(fd, EAL_FLOCK_EXCLUSIVE, EAL_FLOCK_RETURN)) {
RTE_LOG(DEBUG, EAL, "Cannot destroy fbarray - another process is using it\n");
rte_errno = EBUSY;
ret = -1;
@@ -1042,7 +1039,7 @@ rte_fbarray_destroy(struct rte_fbarray *arr)
* we're still holding an exclusive lock, so drop it to
* shared.
*/
- flock(fd, LOCK_SH | LOCK_NB);
+ eal_file_lock(fd, EAL_FLOCK_SHARED, EAL_FLOCK_RETURN);
ret = -1;
goto out;
diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index ecf827914..3aafd892f 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -448,4 +448,49 @@ eal_malloc_no_trace(const char *type, size_t size, unsigned int align);
void eal_free_no_trace(void *addr);
+/** File locking operation. */
+enum eal_flock_op {
+ EAL_FLOCK_SHARED, /**< Acquire a shared lock. */
+ EAL_FLOCK_EXCLUSIVE, /**< Acquire an exclusive lock. */
+ EAL_FLOCK_UNLOCK /**< Release a previously taken lock. */
+};
+
+/** Behavior on file locking conflict. */
+enum eal_flock_mode {
+ EAL_FLOCK_WAIT, /**< Wait until the file gets unlocked to lock it. */
+ EAL_FLOCK_RETURN /**< Return immediately if the file is locked. */
+};
+
+/**
+ * Lock or unlock the file.
+ *
+ * On failure @code rte_errno @endcode is set to the error code
+ * specified by POSIX flock(3) description.
+ *
+ * @param fd
+ * Opened file descriptor.
+ * @param op
+ * Operation to perform.
+ * @param mode
+ * Behavior on conflict.
+ * @return
+ * 0 on success, (-1) on failure.
+ */
+int eal_file_lock(int fd, enum eal_flock_op op, enum eal_flock_mode mode);
+
+/**
+ * Truncate or extend the file to the specified size.
+ *
+ * On failure @code rte_errno @endcode is set to the error code
+ * specified by POSIX ftruncate(3) description.
+ *
+ * @param fd
+ * Opened file descriptor.
+ * @param size
+ * Desired file size.
+ * @return
+ * 0 on success, (-1) on failure.
+ */
+int eal_file_truncate(int fd, ssize_t size);
+
#endif /* _EAL_PRIVATE_H_ */
diff --git a/lib/librte_eal/freebsd/Makefile b/lib/librte_eal/freebsd/Makefile
index a8400f20a..a26c455c7 100644
--- a/lib/librte_eal/freebsd/Makefile
+++ b/lib/librte_eal/freebsd/Makefile
@@ -7,6 +7,7 @@ LIB = librte_eal.a
ARCH_DIR ?= $(RTE_ARCH)
VPATH += $(RTE_SDK)/lib/librte_eal/$(ARCH_DIR)
+VPATH += $(RTE_SDK)/lib/librte_eal/unix
VPATH += $(RTE_SDK)/lib/librte_eal/common
CFLAGS += -I$(SRCDIR)/include
@@ -74,6 +75,9 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_service.c
SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_random.c
SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_reciprocal.c
+# from unix dir
+SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += eal_unix.c
+
# from arch dir
SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_cpuflags.c
SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_hypervisor.c
diff --git a/lib/librte_eal/linux/Makefile b/lib/librte_eal/linux/Makefile
index a77eb1757..fa41f00bf 100644
--- a/lib/librte_eal/linux/Makefile
+++ b/lib/librte_eal/linux/Makefile
@@ -7,6 +7,7 @@ LIB = librte_eal.a
ARCH_DIR ?= $(RTE_ARCH)
VPATH += $(RTE_SDK)/lib/librte_eal/$(ARCH_DIR)
+VPATH += $(RTE_SDK)/lib/librte_eal/unix
VPATH += $(RTE_SDK)/lib/librte_eal/common
CFLAGS += -I$(SRCDIR)/include
@@ -81,6 +82,9 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_service.c
SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_random.c
SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_reciprocal.c
+# from unix dir
+SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += eal_unix.c
+
# from arch dir
SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_cpuflags.c
SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_hypervisor.c
diff --git a/lib/librte_eal/meson.build b/lib/librte_eal/meson.build
index 0267c3b9d..98c97dd07 100644
--- a/lib/librte_eal/meson.build
+++ b/lib/librte_eal/meson.build
@@ -6,6 +6,10 @@ subdir('include')
subdir('common')
+if not is_windows
+ subdir('unix')
+endif
+
dpdk_conf.set('RTE_EXEC_ENV_' + exec_env.to_upper(), 1)
subdir(exec_env)
diff --git a/lib/librte_eal/unix/eal_unix.c b/lib/librte_eal/unix/eal_unix.c
new file mode 100644
index 000000000..b9c57ef18
--- /dev/null
+++ b/lib/librte_eal/unix/eal_unix.c
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Dmitry Kozlyuk
+ */
+
+#include <sys/file.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <rte_errno.h>
+
+#include "eal_private.h"
+
+int
+eal_file_truncate(int fd, ssize_t size)
+{
+ int ret;
+
+ ret = ftruncate(fd, size);
+ if (ret)
+ rte_errno = errno;
+
+ return ret;
+}
+
+int
+eal_file_lock(int fd, enum eal_flock_op op, enum eal_flock_mode mode)
+{
+ int sys_flags = 0;
+ int ret;
+
+ if (mode == EAL_FLOCK_RETURN)
+ sys_flags |= LOCK_NB;
+
+ switch (op) {
+ case EAL_FLOCK_EXCLUSIVE:
+ sys_flags |= LOCK_EX;
+ break;
+ case EAL_FLOCK_SHARED:
+ sys_flags |= LOCK_SH;
+ break;
+ case EAL_FLOCK_UNLOCK:
+ sys_flags |= LOCK_UN;
+ break;
+ }
+
+ ret = flock(fd, sys_flags);
+ if (ret)
+ rte_errno = errno;
+
+ return ret;
+}
diff --git a/lib/librte_eal/unix/meson.build b/lib/librte_eal/unix/meson.build
new file mode 100644
index 000000000..cfa1b4ef9
--- /dev/null
+++ b/lib/librte_eal/unix/meson.build
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2020 Dmitry Kozlyuk
+
+sources += files(
+ 'eal_unix.c',
+)
--
2.25.1
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