diff mbox series

[v8,02/11] eal: introduce internal wrappers for file operations

Message ID 20200610142730.31376-3-dmitry.kozliuk@gmail.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show
Series Windows basic memory management | expand

Checks

Context Check Description
ci/Intel-compilation fail Compilation issues
ci/checkpatch success coding style OK

Commit Message

Dmitry Kozlyuk June 10, 2020, 2:27 p.m. UTC
Introduce OS-independent wrappers in order to support common EAL code
on Unix and Windows:

* eal_file_open: open or create a file.
* eal_file_lock: lock or unlock an open file.
* eal_file_truncate: enforce a given size for an open file.

Implementation for Linux and FreeBSD is placed in "unix" subdirectory,
which is intended for common code between the two. These thin wrappers
require no special maintenance.

Common code supporting multi-process doesn't use the new wrappers,
because it is inherently Unix-specific and would impose excessive
requirements on the wrappers.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
 MAINTAINERS                                |  3 +
 lib/librte_eal/common/eal_common_fbarray.c | 31 ++++-----
 lib/librte_eal/common/eal_private.h        | 73 ++++++++++++++++++++
 lib/librte_eal/freebsd/Makefile            |  4 ++
 lib/librte_eal/linux/Makefile              |  4 ++
 lib/librte_eal/meson.build                 |  4 ++
 lib/librte_eal/unix/eal_file.c             | 80 ++++++++++++++++++++++
 lib/librte_eal/unix/meson.build            |  6 ++
 8 files changed, 186 insertions(+), 19 deletions(-)
 create mode 100644 lib/librte_eal/unix/eal_file.c
 create mode 100644 lib/librte_eal/unix/meson.build

Comments

Thomas Monjalon June 11, 2020, 5:13 p.m. UTC | #1
10/06/2020 16:27, Dmitry Kozlyuk:
> Introduce OS-independent wrappers in order to support common EAL code
> on Unix and Windows:
> 
> * eal_file_open: open or create a file.
> * eal_file_lock: lock or unlock an open file.
> * eal_file_truncate: enforce a given size for an open file.
> 
> Implementation for Linux and FreeBSD is placed in "unix" subdirectory,
> which is intended for common code between the two. These thin wrappers
> require no special maintenance.
[...]
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> +Unix shared files
> +F: lib/librte_eal/unix/

Can be moved in "EAL API and common code".
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index d2b286701..1d9aff26d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -323,6 +323,9 @@  FreeBSD UIO
 M: Bruce Richardson <bruce.richardson@intel.com>
 F: kernel/freebsd/nic_uio/
 
+Unix shared files
+F: lib/librte_eal/unix/
+
 Windows support
 M: Harini Ramakrishnan <harini.ramakrishnan@microsoft.com>
 M: Omar Cardona <ocardona@microsoft.com>
diff --git a/lib/librte_eal/common/eal_common_fbarray.c b/lib/librte_eal/common/eal_common_fbarray.c
index 4f8f1af73..c52ddb967 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>
@@ -85,10 +85,8 @@  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;
 		return -1;
 	}
 
@@ -772,15 +770,15 @@  rte_fbarray_init(struct rte_fbarray *arr, const char *name, unsigned int len,
 		 * and see if we succeed. If we don't, someone else is using it
 		 * already.
 		 */
-		fd = open(path, O_CREAT | O_RDWR, 0600);
+		fd = eal_file_open(path, EAL_OPEN_CREATE | EAL_OPEN_READWRITE);
 		if (fd < 0) {
 			RTE_LOG(DEBUG, EAL, "%s(): couldn't open %s: %s\n",
-					__func__, path, strerror(errno));
-			rte_errno = errno;
+				__func__, path, rte_strerror(rte_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));
+				__func__, path, rte_strerror(rte_errno));
 			rte_errno = EBUSY;
 			goto fail;
 		}
@@ -789,10 +787,8 @@  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;
@@ -888,17 +884,14 @@  rte_fbarray_attach(struct rte_fbarray *arr)
 
 	eal_get_fbarray_path(path, sizeof(path), arr->name);
 
-	fd = open(path, O_RDWR);
+	fd = eal_file_open(path, EAL_OPEN_READWRITE);
 	if (fd < 0) {
-		rte_errno = errno;
 		goto fail;
 	}
 
 	/* 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 +1018,7 @@  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 +1035,7 @@  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 869ce183a..6733a2321 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -420,4 +420,77 @@  eal_malloc_no_trace(const char *type, size_t size, unsigned int align);
 
 void eal_free_no_trace(void *addr);
 
+/** Options for eal_file_open(). */
+enum eal_open_flags {
+	/** Open file for reading. */
+	EAL_OPEN_READONLY = 0x00,
+	/** Open file for reading and writing. */
+	EAL_OPEN_READWRITE = 0x02,
+	/**
+	 * Create the file if it doesn't exist.
+	 * New files are only accessible to the owner (0600 equivalent).
+	 */
+	EAL_OPEN_CREATE = 0x04
+};
+
+/**
+ * Open or create a file.
+ *
+ * @param path
+ *  Path to the file.
+ * @param flags
+ *  A combination of eal_open_flags controlling operation and FD behavior.
+ * @return
+ *  Open file descriptor on success, (-1) on failure and rte_errno is set.
+ */
+int
+eal_file_open(const char *path, int flags);
+
+/** 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 af95386d4..0f8741d96 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-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += eal_file.c
+
 # from arch dir
 SRCS-$(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 48cc34844..331489f99 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-$(CONFIG_RTE_EXEC_ENV_LINUX) += eal_file.c
+
 # from arch dir
 SRCS-$(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 e301f4558..8d492897d 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_file.c b/lib/librte_eal/unix/eal_file.c
new file mode 100644
index 000000000..1b26475ba
--- /dev/null
+++ b/lib/librte_eal/unix/eal_file.c
@@ -0,0 +1,80 @@ 
+/* 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_open(const char *path, int flags)
+{
+	static const int MODE_MASK = EAL_OPEN_READONLY | EAL_OPEN_READWRITE;
+
+	int ret, sys_flags;
+
+	switch (flags & MODE_MASK) {
+	case EAL_OPEN_READONLY:
+		sys_flags = O_RDONLY;
+		break;
+	case EAL_OPEN_READWRITE:
+		sys_flags = O_RDWR;
+		break;
+	default:
+		rte_errno = ENOTSUP;
+		return -1;
+	}
+
+	if (flags & EAL_OPEN_CREATE)
+		sys_flags |= O_CREAT;
+
+	ret = open(path, sys_flags, 0600);
+	if (ret < 0)
+		rte_errno = errno;
+
+	return ret;
+}
+
+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..21029ba1a
--- /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_file.c',
+)