[Sheepdog] [PATCH v3 2/4] sheep: add some candy helpers in util.c

[Liu Yuan]

From: Liu Yuan <tailai.ly at taobao.com>

These are trivial helper wrappers around standard IO functions
and interger hash function. "stolen" from git and Linux kernel.

Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
---
 include/sheepdog_proto.h |    7 ++
 include/util.h           |   14 +++
 lib/util.c               |  214 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 235 insertions(+), 0 deletions(-)
 create mode 100644 lib/util.c

diff --git a/include/sheepdog_proto.h b/include/sheepdog_proto.h
index 65aeef3..198ccdc 100644
--- a/include/sheepdog_proto.h
+++ b/include/sheepdog_proto.h
@@ -216,6 +216,13 @@ static inline uint64_t fnv_64a_buf(void *buf, size_t len, uint64_t hval)
 	return hval;
 }
 
+static inline uint64_t hash_64(uint64_t val, unsigned int bits)
+{
+	uint64_t hash = fnv_64a_buf(&val, sizeof(uint64_t), FNV1A_64_INIT);
+
+	return hash & ((1 << bits) - 1);
+}
+
 static inline int is_data_obj_writeable(struct sheepdog_inode *inode, int idx)
 {
 	return inode->vdi_id == inode->data_vdi_id[idx];
diff --git a/include/util.h b/include/util.h
index 2dccd16..725c8f8 100644
--- a/include/util.h
+++ b/include/util.h
@@ -2,6 +2,8 @@
 #define __UTIL_H__
 
 #include <string.h>
+#include <limits.h>
+#include <stdint.h>
 
 #include "bitops.h"
 
@@ -53,4 +55,16 @@ static inline void *zalloc(size_t size)
 	return calloc(1, size);
 }
 
+typedef void (*try_to_free_t)(size_t);
+extern try_to_free_t set_try_to_free_routine(try_to_free_t);
+
+extern void *xmalloc(size_t size);
+extern void *xzalloc(size_t size);
+extern void *xrealloc(void *ptr, size_t size);
+extern void *xcalloc(size_t nmemb, size_t size);
+extern ssize_t xread(int fd, void *buf, size_t len);
+extern ssize_t xwrite(int fd, const void *buf, size_t len);
+extern ssize_t xpread(int fd, void *buf, size_t count, off_t offset);
+extern ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset);
+
 #endif
diff --git a/lib/util.c b/lib/util.c
new file mode 100644
index 0000000..5a314ba
--- /dev/null
+++ b/lib/util.c
@@ -0,0 +1,214 @@
+/*
+ * Taken and modfied from git by Liu Yuan <namei.unix at gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * 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 <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "util.h"
+#include "logger.h"
+
+static void do_nothing(size_t size)
+{
+}
+
+static void (*try_to_free_routine)(size_t size) = do_nothing;
+
+try_to_free_t set_try_to_free_routine(try_to_free_t routine)
+{
+	try_to_free_t old = try_to_free_routine;
+	if (!routine)
+		routine = do_nothing;
+	try_to_free_routine = routine;
+	return old;
+}
+
+void *xmalloc(size_t size)
+{
+	void *ret = malloc(size);
+	if (!ret && !size)
+		ret = malloc(1);
+	if (!ret) {
+		try_to_free_routine(size);
+		ret = malloc(size);
+		if (!ret && !size)
+			ret = malloc(1);
+		if (!ret)
+			panic("Out of memory");
+	}
+	return ret;
+}
+
+void *xzalloc(size_t size)
+{
+	void *ret;
+	ret = xmalloc(size);
+	memset(ret, 0, size);
+	return ret;
+}
+
+void *xrealloc(void *ptr, size_t size)
+{
+	void *ret = realloc(ptr, size);
+	if (!ret && !size)
+		ret = realloc(ptr, 1);
+	if (!ret) {
+		try_to_free_routine(size);
+		ret = realloc(ptr, size);
+		if (!ret && !size)
+			ret = realloc(ptr, 1);
+		if (!ret)
+			panic("Out of memory");
+	}
+	return ret;
+}
+
+void *xcalloc(size_t nmemb, size_t size)
+{
+	void *ret = calloc(nmemb, size);
+	if (!ret && (!nmemb || !size))
+		ret = calloc(1, 1);
+	if (!ret) {
+		try_to_free_routine(nmemb * size);
+		ret = calloc(nmemb, size);
+		if (!ret && (!nmemb || !size))
+			ret = calloc(1, 1);
+		if (!ret)
+			panic("Out of memory");
+	}
+	return ret;
+}
+
+static ssize_t _read(int fd, void *buf, size_t len)
+{
+	ssize_t nr;
+	while (1) {
+		nr = read(fd, buf, len);
+		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+			continue;
+		return nr;
+	}
+}
+
+static ssize_t _write(int fd, const void *buf, size_t len)
+{
+	ssize_t nr;
+	while (1) {
+		nr = write(fd, buf, len);
+		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+			continue;
+		return nr;
+	}
+}
+
+ssize_t xread(int fd, void *buf, size_t count)
+{
+	char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t loaded = _read(fd, p, count);
+		if (loaded < 0)
+			return -1;
+		if (loaded == 0)
+			return total;
+		count -= loaded;
+		p += loaded;
+		total += loaded;
+	}
+
+	return total;
+}
+
+ssize_t xwrite(int fd, const void *buf, size_t count)
+{
+	const char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t written = _write(fd, p, count);
+		if (written < 0)
+			return -1;
+		if (!written) {
+			errno = ENOSPC;
+			return -1;
+		}
+		count -= written;
+		p += written;
+		total += written;
+	}
+
+	return total;
+}
+
+static ssize_t _pread(int fd, void *buf, size_t len, off_t offset)
+{
+	ssize_t nr;
+	while (1) {
+		nr = pread(fd, buf, len, offset);
+		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+			continue;
+		return nr;
+	}
+}
+
+static ssize_t _pwrite(int fd, const void *buf, size_t len, off_t offset)
+{
+	ssize_t nr;
+	while (1) {
+		nr = pwrite(fd, buf, len, offset);
+		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
+			continue;
+		return nr;
+	}
+}
+
+ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
+{
+	char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t loaded = _pread(fd, p, count, offset);
+		if (loaded < 0)
+			return -1;
+		if (loaded == 0)
+			return total;
+		count -= loaded;
+		p += loaded;
+		total += loaded;
+		offset += loaded;
+	}
+
+	return total;
+}
+
+ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+	const char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t written = _pwrite(fd, p, count, offset);
+		if (written < 0)
+			return -1;
+		if (!written) {
+			errno = ENOSPC;
+			return -1;
+		}
+		count -= written;
+		p += written;
+		total += written;
+		offset += written;
+	}
+
+	return total;
+}
-- 
1.7.6.1