posix: device_io: implement pread() and pwrite() (5ccbaeff) · Commits · Wenxi XU / zephyr

lib/os/fdtable.c

+41 −13

Original line number	Diff line number	Diff line
		@@ -302,9 +302,21 @@ int zvfs_alloc_fd(void obj, const struct fd_op_vtable vtable)
		return fd;
		}

		static ssize_t zvfs_rw(int fd, void *buf, size_t sz, bool is_write)
		static bool supports_pread_pwrite(uint32_t mode)
		{
		switch (mode & ZVFS_MODE_IFMT) {
		case ZVFS_MODE_IFSHM:
		return true;
		default:
		return false;
		}
		}

		static ssize_t zvfs_rw(int fd, void buf, size_t sz, bool is_write, const size_t from_offset)
		{
		bool prw;
		ssize_t res;
		const size_t *off;

		if (_check_fd(fd) < 0) {
		return -1;
		@@ -312,24 +324,40 @@ static ssize_t zvfs_rw(int fd, void *buf, size_t sz, bool is_write)

		(void)k_mutex_lock(&fdtable[fd].lock, K_FOREVER);

		prw = supports_pread_pwrite(fdtable[fd].mode);
		if (from_offset != NULL && !prw) {
		/*
		* Seekable file types should support pread() / pwrite() and per-fd offset passing.
		* Otherwise, it's a bug.
		*/
		errno = ENOTSUP;
		res = -1;
		goto unlock;
		}

		/* If there is no specified from_offset, then use the current offset of the fd */
		off = (from_offset == NULL) ? &fdtable[fd].offset : from_offset;

		if (is_write) {
		if (fdtable[fd].vtable->write_offset == NULL) {
		if (fdtable[fd].vtable->write_offs == NULL) {
		res = -1;
		errno = EIO;
		} else {
		res = fdtable[fd].vtable->write_offset(fdtable[fd].obj, buf, sz,
		fdtable[fd].offset);
		res = fdtable[fd].vtable->write_offs(fdtable[fd].obj, buf, sz, *off);
		}
		} else {
		if (fdtable[fd].vtable->read == NULL) {
		if (fdtable[fd].vtable->read_offs == NULL) {
		res = -1;
		errno = EIO;
		} else {
		res = fdtable[fd].vtable->read_offset(fdtable[fd].obj, buf, sz,
		fdtable[fd].offset);
		res = fdtable[fd].vtable->read_offs(fdtable[fd].obj, buf, sz, *off);
		}
		}
		if (res > 0) {
		if (res > 0 && prw && from_offset == NULL) {
		/*
		* only update the fd offset when from_offset is not specified
		* See pread() / pwrite()
		*/
		fdtable[fd].offset += res;
		}

		@@ -339,14 +367,14 @@ unlock:
		return res;
		}

		ssize_t zvfs_read(int fd, void *buf, size_t sz)
		ssize_t zvfs_read(int fd, void buf, size_t sz, const size_t from_offset)
		{
		return zvfs_rw(fd, buf, sz, false);
		return zvfs_rw(fd, buf, sz, false, from_offset);
		}

		ssize_t zvfs_write(int fd, const void *buf, size_t sz)
		ssize_t zvfs_write(int fd, const void buf, size_t sz, const size_t from_offset)
		{
		return zvfs_rw(fd, (void *)buf, sz, true);
		return zvfs_rw(fd, (void *)buf, sz, true, from_offset);
		}

		int zvfs_close(int fd)
		@@ -488,7 +516,7 @@ static ssize_t stdinout_read_vmeth(void obj, void buffer, size_t count)
		static ssize_t stdinout_write_vmeth(void obj, const void buffer, size_t count)
		{
		#if defined(CONFIG_BOARD_NATIVE_POSIX)
		return zvfs_write(1, buffer, count);
		return zvfs_write(1, buffer, count, NULL);
		#elif defined(CONFIG_NEWLIB_LIBC) \|\| defined(CONFIG_ARCMWDT_LIBC)
		return z_impl_zephyr_write_stdout(buffer, count);
		#else

lib/posix/options/device_io.c

+28 −4

Original line number	Diff line number	Diff line
		@@ -15,8 +15,8 @@
		/* prototypes for external, not-yet-public, functions in fdtable.c or fs.c */
		int zvfs_close(int fd);
		int zvfs_open(const char *name, int flags);
		ssize_t zvfs_read(int fd, void *buf, size_t sz);
		ssize_t zvfs_write(int fd, const void *buf, size_t sz);
		ssize_t zvfs_read(int fd, void buf, size_t sz, size_t from_offset);
		ssize_t zvfs_write(int fd, const void buf, size_t sz, size_t from_offset);

		int close(int fd)
		{
		@@ -41,9 +41,33 @@ int poll(struct pollfd *fds, int nfds, int timeout)
		return zsock_poll(fds, nfds, timeout);
		}

		ssize_t pread(int fd, void *buf, size_t count, off_t offset)
		{
		size_t off = (size_t)offset;

		if (offset < 0) {
		errno = EINVAL;
		return -1;
		}

		return zvfs_read(fd, buf, count, (size_t *)&off);
		}

		ssize_t pwrite(int fd, void *buf, size_t count, off_t offset)
		{
		size_t off = (size_t)offset;

		if (offset < 0) {
		errno = EINVAL;
		return -1;
		}

		return zvfs_write(fd, buf, count, (size_t *)&off);
		}

		ssize_t read(int fd, void *buf, size_t sz)
		{
		return zvfs_read(fd, buf, sz);
		return zvfs_read(fd, buf, sz, NULL);
		}
		#ifdef CONFIG_POSIX_DEVICE_IO_ALIAS_READ
		FUNC_ALIAS(read, _read, ssize_t);
		@@ -57,7 +81,7 @@ int select(int nfds, fd_set readfds, fd_set writefds, fd_set *exceptfds, struc

		ssize_t write(int fd, const void *buf, size_t sz)
		{
		return zvfs_write(fd, buf, sz);
		return zvfs_write(fd, buf, sz, NULL);
		}
		#ifdef CONFIG_POSIX_DEVICE_IO_ALIAS_WRITE
		FUNC_ALIAS(write, _write, ssize_t);

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