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-rw-r--r--src/common/safe_io.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/src/common/safe_io.c b/src/common/safe_io.c
new file mode 100644
index 000000000..80921d0f2
--- /dev/null
+++ b/src/common/safe_io.c
@@ -0,0 +1,297 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2011 New Dream Network
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+
+#include "common/safe_io.h"
+#include "include/compat.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/socket.h>
+
+ssize_t safe_read(int fd, void *buf, size_t count)
+{
+ size_t cnt = 0;
+
+ while (cnt < count) {
+ ssize_t r = read(fd, buf, count - cnt);
+ if (r <= 0) {
+ if (r == 0) {
+ // EOF
+ return cnt;
+ }
+ if (errno == EINTR)
+ continue;
+ return -errno;
+ }
+ cnt += r;
+ buf = (char *)buf + r;
+ }
+ return cnt;
+}
+
+#ifdef _WIN32
+// "read" doesn't work with Windows sockets.
+ssize_t safe_recv(int fd, void *buf, size_t count)
+{
+ size_t cnt = 0;
+
+ while (cnt < count) {
+ ssize_t r = recv(fd, (SOCKOPT_VAL_TYPE)buf, count - cnt, 0);
+ if (r <= 0) {
+ if (r == 0) {
+ // EOF
+ return cnt;
+ }
+ int err = ceph_sock_errno();
+ if (err == EAGAIN || err == EINTR) {
+ continue;
+ }
+ return -err;
+ }
+ cnt += r;
+ buf = (char *)buf + r;
+ }
+ return cnt;
+}
+#else
+ssize_t safe_recv(int fd, void *buf, size_t count)
+{
+ // We'll use "safe_read" so that this can work with any type of
+ // file descriptor.
+ return safe_read(fd, buf, count);
+}
+#endif /* _WIN32 */
+
+ssize_t safe_read_exact(int fd, void *buf, size_t count)
+{
+ ssize_t ret = safe_read(fd, buf, count);
+ if (ret < 0)
+ return ret;
+ if ((size_t)ret != count)
+ return -EDOM;
+ return 0;
+}
+
+ssize_t safe_recv_exact(int fd, void *buf, size_t count)
+{
+ ssize_t ret = safe_recv(fd, buf, count);
+ if (ret < 0)
+ return ret;
+ if ((size_t)ret != count)
+ return -EDOM;
+ return 0;
+}
+
+ssize_t safe_write(int fd, const void *buf, size_t count)
+{
+ while (count > 0) {
+ ssize_t r = write(fd, buf, count);
+ if (r < 0) {
+ if (errno == EINTR)
+ continue;
+ return -errno;
+ }
+ count -= r;
+ buf = (char *)buf + r;
+ }
+ return 0;
+}
+
+#ifdef _WIN32
+ssize_t safe_send(int fd, const void *buf, size_t count)
+{
+ while (count > 0) {
+ ssize_t r = send(fd, (SOCKOPT_VAL_TYPE)buf, count, 0);
+ if (r < 0) {
+ int err = ceph_sock_errno();
+ if (err == EINTR || err == EAGAIN) {
+ continue;
+ }
+ return -err;
+ }
+ count -= r;
+ buf = (char *)buf + r;
+ }
+ return 0;
+}
+#else
+ssize_t safe_send(int fd, const void *buf, size_t count)
+{
+ return safe_write(fd, buf, count);
+}
+#endif /* _WIN32 */
+
+ssize_t safe_pread(int fd, void *buf, size_t count, off_t offset)
+{
+ size_t cnt = 0;
+ char *b = (char*)buf;
+
+ while (cnt < count) {
+ ssize_t r = pread(fd, b + cnt, count - cnt, offset + cnt);
+ if (r <= 0) {
+ if (r == 0) {
+ // EOF
+ return cnt;
+ }
+ if (errno == EINTR)
+ continue;
+ return -errno;
+ }
+
+ cnt += r;
+ }
+ return cnt;
+}
+
+ssize_t safe_pread_exact(int fd, void *buf, size_t count, off_t offset)
+{
+ ssize_t ret = safe_pread(fd, buf, count, offset);
+ if (ret < 0)
+ return ret;
+ if ((size_t)ret != count)
+ return -EDOM;
+ return 0;
+}
+
+ssize_t safe_pwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+ while (count > 0) {
+ ssize_t r = pwrite(fd, buf, count, offset);
+ if (r < 0) {
+ if (errno == EINTR)
+ continue;
+ return -errno;
+ }
+ count -= r;
+ buf = (char *)buf + r;
+ offset += r;
+ }
+ return 0;
+}
+
+#ifdef CEPH_HAVE_SPLICE
+ssize_t safe_splice(int fd_in, off_t *off_in, int fd_out, off_t *off_out,
+ size_t len, unsigned int flags)
+{
+ size_t cnt = 0;
+
+ while (cnt < len) {
+ ssize_t r = splice(fd_in, off_in, fd_out, off_out, len - cnt, flags);
+ if (r <= 0) {
+ if (r == 0) {
+ // EOF
+ return cnt;
+ }
+ if (errno == EINTR)
+ continue;
+ if (errno == EAGAIN)
+ break;
+ return -errno;
+ }
+ cnt += r;
+ }
+ return cnt;
+}
+
+ssize_t safe_splice_exact(int fd_in, off_t *off_in, int fd_out,
+ off_t *off_out, size_t len, unsigned int flags)
+{
+ ssize_t ret = safe_splice(fd_in, off_in, fd_out, off_out, len, flags);
+ if (ret < 0)
+ return ret;
+ if ((size_t)ret != len)
+ return -EDOM;
+ return 0;
+}
+#endif
+
+int safe_write_file(const char *base, const char *file,
+ const char *val, size_t vallen,
+ unsigned mode)
+{
+ int ret;
+ char fn[PATH_MAX];
+ char tmp[PATH_MAX];
+ int fd;
+
+ // does the file already have correct content?
+ char oldval[80];
+ ret = safe_read_file(base, file, oldval, sizeof(oldval));
+ if (ret == (int)vallen && memcmp(oldval, val, vallen) == 0)
+ return 0; // yes.
+
+ snprintf(fn, sizeof(fn), "%s/%s", base, file);
+ snprintf(tmp, sizeof(tmp), "%s/%s.tmp", base, file);
+ fd = open(tmp, O_WRONLY|O_CREAT|O_TRUNC|O_BINARY, mode);
+ if (fd < 0) {
+ ret = errno;
+ return -ret;
+ }
+ ret = safe_write(fd, val, vallen);
+ if (ret) {
+ VOID_TEMP_FAILURE_RETRY(close(fd));
+ return ret;
+ }
+
+ ret = fsync(fd);
+ if (ret < 0) ret = -errno;
+ VOID_TEMP_FAILURE_RETRY(close(fd));
+ if (ret < 0) {
+ unlink(tmp);
+ return ret;
+ }
+ ret = rename(tmp, fn);
+ if (ret < 0) {
+ ret = -errno;
+ unlink(tmp);
+ return ret;
+ }
+
+ fd = open(base, O_RDONLY|O_BINARY);
+ if (fd < 0) {
+ ret = -errno;
+ return ret;
+ }
+ ret = fsync(fd);
+ if (ret < 0) ret = -errno;
+ VOID_TEMP_FAILURE_RETRY(close(fd));
+
+ return ret;
+}
+
+int safe_read_file(const char *base, const char *file,
+ char *val, size_t vallen)
+{
+ char fn[PATH_MAX];
+ int fd, len;
+
+ snprintf(fn, sizeof(fn), "%s/%s", base, file);
+ fd = open(fn, O_RDONLY|O_BINARY);
+ if (fd < 0) {
+ return -errno;
+ }
+ len = safe_read(fd, val, vallen);
+ if (len < 0) {
+ VOID_TEMP_FAILURE_RETRY(close(fd));
+ return len;
+ }
+ // close sometimes returns errors, but only after write()
+ VOID_TEMP_FAILURE_RETRY(close(fd));
+
+ return len;
+}
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