libasys

Signed-off-by: Jeremy Allison <jra@samba.org>

4 files changed, 521 insertions, 0 deletions

diff --git a/source3/lib/asys/asys.c b/source3/lib/asys/asys.c
new file mode 100644
index 0000000000..766a716f9a
--- /dev/null
+++ b/source3/lib/asys/asys.c
@@ -0,0 +1,274 @@
+/*
+ * Async syscalls
+ * Copyright (C) Volker Lendecke 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "asys.h"
+#include <stdlib.h>
+#include <errno.h>
+#include "../pthreadpool/pthreadpool.h"
+
+struct asys_pwrite_args {
+	int fildes;
+	const void *buf;
+	size_t nbyte;
+	off_t offset;
+};
+
+struct asys_pread_args {
+	int fildes;
+	void *buf;
+	size_t nbyte;
+	off_t offset;
+};
+
+union asys_job_args {
+	struct asys_pwrite_args pwrite_args;
+	struct asys_pread_args pread_args;
+};
+
+struct asys_job {
+	void *private_data;
+	union asys_job_args args;
+	ssize_t ret;
+	int err;
+	char busy;
+	char canceled;
+};
+
+struct asys_context {
+	struct pthreadpool *pool;
+	int pthreadpool_fd;
+
+	unsigned num_jobs;
+	struct asys_job **jobs;
+};
+
+struct asys_creds_context {
+	int dummy;
+};
+
+int asys_context_init(struct asys_context **pctx, unsigned max_parallel)
+{
+	struct asys_context *ctx;
+	int ret;
+
+	ctx = calloc(1, sizeof(struct asys_context));
+	if (ctx == NULL) {
+		return ENOMEM;
+	}
+	ret = pthreadpool_init(max_parallel, &ctx->pool);
+	if (ret != 0) {
+		free(ctx);
+		return ret;
+	}
+	ctx->pthreadpool_fd = pthreadpool_signal_fd(ctx->pool);
+
+	*pctx = ctx;
+	return 0;
+}
+
+int asys_signalfd(struct asys_context *ctx)
+{
+	return ctx->pthreadpool_fd;
+}
+
+int asys_context_destroy(struct asys_context *ctx)
+{
+	int ret;
+	unsigned i;
+
+	for (i=0; i<ctx->num_jobs; i++) {
+		if (ctx->jobs[i]->busy) {
+			return EBUSY;
+		}
+	}
+
+	ret = pthreadpool_destroy(ctx->pool);
+	if (ret != 0) {
+		return ret;
+	}
+	for (i=0; i<ctx->num_jobs; i++) {
+		free(ctx->jobs[i]);
+	}
+	free(ctx->jobs);
+	free(ctx);
+	return 0;
+}
+
+static int asys_new_job(struct asys_context *ctx, int *jobid,
+			struct asys_job **pjob)
+{
+	struct asys_job **tmp;
+	struct asys_job *job;
+	unsigned i;
+
+	for (i=0; i<ctx->num_jobs; i++) {
+		job = ctx->jobs[i];
+		if (!job->busy) {
+			job->err = 0;
+			*pjob = job;
+			*jobid = i;
+			return 0;
+		}
+	}
+
+	if (ctx->num_jobs+1 == 0) {
+		return EBUSY; 	/* overflow */
+	}
+
+	tmp = realloc(ctx->jobs, sizeof(struct asys_job *)*(ctx->num_jobs+1));
+	if (tmp == NULL) {
+		return ENOMEM;
+	}
+	ctx->jobs = tmp;
+
+	job = calloc(1, sizeof(struct asys_job));
+	if (job == NULL) {
+		return ENOMEM;
+	}
+	ctx->jobs[ctx->num_jobs] = job;
+
+	*jobid = ctx->num_jobs;
+	*pjob = job;
+	ctx->num_jobs += 1;
+	return 0;
+}
+
+static void asys_pwrite_do(void *private_data);
+
+int asys_pwrite(struct asys_context *ctx, int fildes, const void *buf,
+		size_t nbyte, off_t offset, void *private_data)
+{
+	struct asys_job *job;
+	struct asys_pwrite_args *args;
+	int jobid;
+	int ret;
+
+	ret = asys_new_job(ctx, &jobid, &job);
+	if (ret != 0) {
+		return ret;
+	}
+	job->private_data = private_data;
+
+	args = &job->args.pwrite_args;
+	args->fildes = fildes;
+	args->buf = buf;
+	args->nbyte = nbyte;
+	args->offset = offset;
+
+	ret = pthreadpool_add_job(ctx->pool, jobid, asys_pwrite_do, job);
+	if (ret != 0) {
+		return ret;
+	}
+	job->busy = 1;
+
+	return 0;
+}
+
+static void asys_pwrite_do(void *private_data)
+{
+	struct asys_job *job = (struct asys_job *)private_data;
+	struct asys_pwrite_args *args = &job->args.pwrite_args;
+
+	job->ret = pwrite(args->fildes, args->buf, args->nbyte, args->offset);
+	if (job->ret == -1) {
+		job->err = errno;
+	}
+}
+
+static void asys_pread_do(void *private_data);
+
+int asys_pread(struct asys_context *ctx, int fildes, void *buf,
+	       size_t nbyte, off_t offset, void *private_data)
+{
+	struct asys_job *job;
+	struct asys_pread_args *args;
+	int jobid;
+	int ret;
+
+	ret = asys_new_job(ctx, &jobid, &job);
+	if (ret != 0) {
+		return ret;
+	}
+	job->private_data = private_data;
+
+	args = &job->args.pread_args;
+	args->fildes = fildes;
+	args->buf = buf;
+	args->nbyte = nbyte;
+	args->offset = offset;
+
+	ret = pthreadpool_add_job(ctx->pool, jobid, asys_pread_do, job);
+	if (ret != 0) {
+		return ret;
+	}
+	job->busy = 1;
+
+	return 0;
+}
+
+static void asys_pread_do(void *private_data)
+{
+	struct asys_job *job = (struct asys_job *)private_data;
+	struct asys_pread_args *args = &job->args.pread_args;
+
+	job->ret = pread(args->fildes, args->buf, args->nbyte, args->offset);
+	if (job->ret == -1) {
+		job->err = errno;
+	}
+}
+
+void asys_cancel(struct asys_context *ctx, void *private_data)
+{
+	unsigned i;
+
+	for (i=0; i<ctx->num_jobs; i++) {
+		struct asys_job *job = ctx->jobs[i];
+
+		if (job->private_data == private_data) {
+			job->canceled = 1;
+		}
+	}
+}
+
+int asys_result(struct asys_context *ctx, ssize_t *pret, int *perrno,
+		void *pdata)
+{
+	void **pprivate_data = (void **)pdata;
+	struct asys_job *job;
+	int ret, jobid;
+
+	ret = pthreadpool_finished_job(ctx->pool, &jobid);
+	if (ret != 0) {
+		return ret;
+	}
+	if ((jobid < 0) || (jobid >= ctx->num_jobs)) {
+		return EIO;
+	}
+
+	job = ctx->jobs[jobid];
+
+	if (job->canceled) {
+		return ECANCELED;
+	}
+
+	*pret = job->ret;
+	*perrno = job->err;
+	*pprivate_data = job->private_data;
+	job->busy = 0;
+	return 0;
+}
diff --git a/source3/lib/asys/asys.h b/source3/lib/asys/asys.h
new file mode 100644
index 0000000000..73f1051f61
--- /dev/null
+++ b/source3/lib/asys/asys.h
@@ -0,0 +1,146 @@
+/*
+ * Async syscalls
+ * Copyright (C) Volker Lendecke 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASYS_H__
+#define __ASYS_H__
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+/**
+ * @defgroup asys The async syscall library
+ *
+ * This module contains a set of asynchronous functions that directly
+ * wrap normally synchronous posix system calls. The reason for this
+ * module's existence is the limited set of operations the posix async
+ * I/O API provides.
+ *
+ * The basic flow of operations is:
+ *
+ * The application creates a asys_context structure using
+ * asys_context_create()
+ *
+ * The application triggers a call to the library by calling for
+ * example asys_ftruncate(). asys_ftruncate() takes a private_data
+ * argument that will be returned later by asys_result. The calling
+ * application should hand a pointer representing the async operation
+ * to the private_data argument.
+ *
+ * The application puts the fd returned by asys_signalfd() into its
+ * event loop. When the signal fd becomes readable, the application
+ * calls asys_result() to grab the final result of one of the system
+ * calls that were issued in the meantime.
+ *
+ * For multi-user applications it is necessary to create different
+ * credential contexts, as it is not clear when exactly the real
+ * system call will be issued. The application might have called
+ * seteuid(2) or something equivalent in the meantime. Thus, all
+ * system calls doing access checks, in particular all calls doing
+ * path-based operations, require a struct auth_creds_context
+ * parameter. asys_creds_context_create() creates such a context. All
+ * credential-checking operations take a struct asys_creds_context as
+ * an argument. It can be NULL if the application never changes
+ * credentials.
+ *
+ * @{
+ */
+
+struct asys_context;
+struct asys_creds_context;
+
+enum asys_log_level {
+	ASYS_LOG_FATAL = 0,
+	ASYS_DEBUG_ERROR,
+	ASYS_DEBUG_WARNING,
+	ASYS_DEBUG_TRACE
+};
+
+#ifndef PRINTF_ATTRIBUTE
+#if (__GNUC__ >= 3)
+/** Use gcc attribute to check printf fns.  a1 is the 1-based index of
+ * the parameter containing the format, and a2 the index of the first
+ * argument. Note that some gcc 2.x versions don't handle this
+ * properly **/
+#define PRINTF_ATTRIBUTE(a1, a2) __attribute__ ((format (__printf__, a1, a2)))
+#else
+#define PRINTF_ATTRIBUTE(a1, a2)
+#endif
+#endif
+
+typedef void (*asys_log_fn)(struct asys_context *ctx, void *private_data,
+			    enum asys_log_level level,
+			    const char *fmt, ...) PRINTF_ATTRIBUTE(4, 5);
+
+int asys_context_init(struct asys_context **ctx, unsigned max_parallel);
+int asys_context_destroy(struct asys_context *ctx);
+void asys_set_log_fn(struct asys_context *ctx, asys_log_fn fn,
+		     void *private_data);
+
+/**
+ * @brief Get the the signal fd
+ *
+ * asys_signalfd() returns a file descriptor that will become readable
+ * whenever an asynchronous request has finished. When the signalfd is
+ * readable, calling asys_result() will not block.
+ *
+ * @param[in]	ctx	The asys context
+ * @return		A file descriptor indicating a finished operation
+ */
+
+int asys_signalfd(struct asys_context *ctx);
+
+/**
+ * @brief Pull the result from an async operation
+ *
+ * Whe the fd returned from asys_signalfd() is readable, an async
+ * operation has finished. The result from the async operation can be
+ * pulled with asys_result().
+ *
+ * @param[in]	ctx	The asys context
+ * @return		success: 0, failure: errno
+ */
+int asys_result(struct asys_context *ctx, ssize_t *pret, int *perrno,
+		void *pdata);
+void asys_cancel(struct asys_context *ctx, void *private_data);
+
+int asys_pread(struct asys_context *ctx, int fildes, void *buf, size_t nbyte,
+	       off_t offset, void *private_data);
+int asys_pwrite(struct asys_context *ctx, int fildes, const void *buf,
+		size_t nbyte, off_t offset, void *private_data);
+int asys_ftruncate(struct asys_context *ctx, int filedes, off_t length,
+		   void *private_data);
+int asys_fsync(struct asys_context *ctx, int fd, void *private_data);
+int asys_close(struct asys_context *ctx, int fd, void *private_data);
+
+struct asys_creds_context *asys_creds_context_create(
+	struct asys_context *ctx,
+	uid_t uid, gid_t gid, unsigned num_gids, gid_t *gids);
+
+int asys_creds_context_delete(struct asys_creds_context *ctx);
+
+int asys_open(struct asys_context *ctx, struct asys_creds_context *cctx,
+	      const char *pathname, int flags, mode_t mode,
+	      void *private_data);
+int asys_unlink(struct asys_context *ctx, struct asys_creds_context *cctx,
+		const char *pathname, void *private_data);
+
+/* @} */
+
+#endif /* __ASYS_H__ */
diff --git a/source3/lib/asys/tests.c b/source3/lib/asys/tests.c
new file mode 100644
index 0000000000..354f1bfbdb
--- /dev/null
+++ b/source3/lib/asys/tests.c
@@ -0,0 +1,92 @@
+/*
+ * Test async syscalls
+ * Copyright (C) Volker Lendecke 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "asys.h"
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+int main(int argc, const char *argv[])
+{
+	struct asys_context *ctx;
+	int i, fd, ret;
+
+	int *buf;
+
+	int ntasks = 10;
+
+	ret = asys_context_init(&ctx, 0);
+	if (ret != 0) {
+		perror("asys_context_create failed");
+		return 1;
+	}
+
+	fd = open("asys_testfile", O_CREAT|O_RDWR, 0644);
+	if (fd == -1) {
+		perror("open failed");
+		return 1;
+	}
+
+	buf = calloc(ntasks, sizeof(int));
+	if (buf == NULL) {
+		perror("calloc failed");
+		return 1;
+	}
+
+	for (i=0; i<ntasks; i++) {
+		buf[i] = i;
+	}
+
+	for (i=0; i<ntasks; i++) {
+		ret = asys_pwrite(ctx, fd, &buf[i], sizeof(int),
+				  i * sizeof(int), &buf[i]);
+		if (ret != 0) {
+			errno = ret;
+			perror("asys_pwrite failed");
+			return 1;
+		}
+	}
+
+	for (i=0; i<ntasks; i++) {
+		void *priv;
+		ssize_t retval;
+		int err;
+		int *pidx;
+
+		ret = asys_result(ctx, &retval, &err, &priv);
+		if (ret == -1) {
+			errno = ret;
+			perror("asys_result failed");
+			return 1;
+		}
+		pidx = (int *)priv;
+
+		printf("%d returned %d\n", *pidx, (int)retval);
+	}
+
+	ret = asys_context_destroy(ctx);
+	if (ret != 0) {
+		perror("asys_context_delete failed");
+		return 1;
+	}
+
+	free(buf);
+
+	return 0;
+}
diff --git a/source3/lib/asys/wscript_build b/source3/lib/asys/wscript_build
new file mode 100644
index 0000000000..7b6d2365e6
--- /dev/null
+++ b/source3/lib/asys/wscript_build
@@ -0,0 +1,9 @@
+#!/usr/bin/env python
+
+bld.SAMBA3_SUBSYSTEM('LIBASYS',
+		     source='asys.c',
+		     deps='PTHREADPOOL')
+
+bld.SAMBA3_BINARY('asystest',
+		  source='tests.c',
+		  deps='LIBASYS')