add: [ipc] implementation of shm

src/libipc/platform/posix/def.h

@@ -0,0 +1,17 @@
+/**
+ * @file libipc/platform/posix/mmap.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include "libipc/def.h"
+
+LIBIPC_NAMESPACE_BEG_
+namespace posix {
+
+enum : int {
+  failed = -1,
+};
+
+} // namespace posix
+LIBIPC_NAMESPACE_END_

src/libipc/platform/posix/mmap.h

@@ -1,27 +0,0 @@
-/**
- * @file libipc/platform/posix/mmap.h
- * @author mutouyun (orz@orzz.org)
- */
-#pragma once
-
-#include <string>
-#include <cstddef>
-
-#include "libipc/shm.h"
-
-LIBIPC_NAMESPACE_BEG_
-
-struct mmap_handle {
-  std::string file;
-  std::size_t f_sz;
-  std::size_t f_of;
-  void *memp;
-};
-
-inline int mmap_open_(mmap_handle *h_out, std::string const &file, int fd, int flags, std::size_t f_sz, std::size_t f_of) noexcept {
-  if (h_out == nullptr) {
-    return -1;
-  }
-}
-
-LIBIPC_NAMESPACE_END_

src/libipc/platform/posix/shm_impl.h

@@ -0,0 +1,125 @@
+/**
+ * @file libipc/platform/posix/shm_impl.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <string>
+#include <cstddef>
+
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "libimp/log.h"
+#include "libimp/system.h"
+
+#include "libipc/shm.h"
+
+#include "def.h"
+
+LIBIPC_NAMESPACE_BEG_
+using namespace ::LIBIMP_;
+
+struct shm_handle {
+  std::string file;
+  std::size_t f_sz;
+  void *memp;
+};
+
+/**
+ * @see https://man7.org/linux/man-pages/man3/shm_open.3.html
+ *      https://man7.org/linux/man-pages/man3/fstat.3p.html
+ *      https://man7.org/linux/man-pages/man3/ftruncate.3p.html
+ *      https://man7.org/linux/man-pages/man2/mmap.2.html
+ */
+result<shm_t> shm_open(std::string name, std::size_t size, mode::type type) noexcept {
+  LIBIMP_LOG_();
+  if (name.empty()) {
+    log.error("name is empty.");
+    return {};
+  }
+
+  /// @brief Open the object for read-write access.
+  int flag = O_RDWR;
+  switch (type) {
+  case mode::open:
+    size = 0;
+    break;
+  // The check for the existence of the object, 
+  // and its creation if it does not exist, are performed atomically.
+  case mode::create:
+    flag |= O_CREAT | O_EXCL;
+    break;
+  // Create the shared memory object if it does not exist.
+  case mode::open | mode::create:
+    flag |= O_CREAT;
+    break;
+  default:
+    log.error("mode type is invalid. type = {}", type);
+    return {};
+  }
+
+  /// @brief Create/Open POSIX shared memory bject
+  int fd = ::shm_open(name.c_str(), flag, S_IRUSR | S_IWUSR |
+                                          S_IRGRP | S_IWGRP |
+                                          S_IROTH | S_IWOTH);
+  if (fd == posix::failed) {
+    log.error("shm_open fails. error = {}", sys::error_msg(sys::error_code()));
+    return {};
+  }
+
+  if (size == 0) {
+    /// @brief Try to get the size of this fd
+    struct stat st;
+    if (::fstat(fd, &st) == posix::failed) {
+      log.error("fstat fails. error = {}", sys::error_msg(sys::error_code()));
+      ::shm_unlink(name.c_str());
+      return {};
+    }
+    size = static_cast<std::size_t>(st.st_size);
+    /// @brief Truncate this fd to a specified length
+  } else if (::ftruncate(fd, size) != 0) {
+    log.error("ftruncate fails. error = {}", sys::error_msg(sys::error_code()));
+    ::shm_unlink(name.c_str());
+    return {};
+  }
+
+  /// @brief Creates a new mapping in the virtual address space of the calling process.
+  void *mem = ::mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+  if (mem == MAP_FAILED) {
+    log.error("mmap fails. error = {}", sys::error_msg(sys::error_code()));
+    ::shm_unlink(name.c_str());
+    return {};
+  }
+  ::close(fd);
+  return new shm_handle{std::move(name), size, mem};
+}
+
+/**
+ * @see https://man7.org/linux/man-pages/man2/mmap.2.html
+ */
+result_code shm_close(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  if (shm->memp == nullptr) {
+    log.error("memory pointer is null.");
+    return {};
+  }
+  if (::munmap(shm->memp, shm->f_sz) == posix::failed) {
+    auto ec = sys::error_code();
+    log.error("munmap fails. error = {}", sys::error_msg(ec));
+    return ec;
+  }
+  /// @brief no unlink the file.
+  delete shm;
+  return {true};
+}
+
+LIBIPC_NAMESPACE_END_

src/libipc/platform/win/get_sa.h

@@ -1,3 +1,7 @@
+/**
+ * @file libipc/platform/win/get_sa.h
+ * @author mutouyun (orz@orzz.org)
+ */
 #pragma once
 
 #include <securitybaseapi.h>

src/libipc/platform/win/mmap_impl.h

@@ -1,5 +1,5 @@
 /**
- * @file libipc/platform/win/mmap.h
+ * @file libipc/platform/win/mmap_impl.h
  * @author mutouyun (orz@orzz.org)
  */
 #pragma once
@@ -150,31 +150,4 @@ void mmap_release(HANDLE h, LPCVOID mem) {
 }
 
 } // namespace
-
-::LIBIMP_::result<shm_t> shm_open(std::string name, std::size_t size, mode::type type) noexcept {
-  LIBIMP_LOG_();
-  auto h = mmap_open(name, size, type);
-  if (h == NULL) {
-    log.error("mmap_open failed.");
-    return {nullptr, *sys::error_code()};
-  }
-  auto mem = mmap_memof(h);
-  if (mem == NULL) {
-    log.warning("mmap_memof failed.");
-  }
-  return new shm_handle{std::move(name), mmap_sizeof(mem), mem, h};
-}
-
-::LIBIMP_::result_code shm_close(shm_t h) noexcept {
-  LIBIMP_LOG_();
-  if (h == nullptr) {
-    log.error("shm handle is null.");
-    return {};
-  }
-  auto shm = static_cast<shm_handle *>(h);
-  mmap_release(shm->h_fmap, shm->memp);
-  delete shm;
-  return {true};
-}
-
 LIBIPC_NAMESPACE_END_

src/libipc/platform/win/shm_impl.h

@@ -0,0 +1,46 @@
+/**
+ * @file libipc/platform/win/shm_impl.h
+ * @author mutouyun (orz@orzz.org)
+ */
+#pragma once
+
+#include <string>
+#include <cstddef>
+
+#include "libimp/log.h"
+#include "libimp/system.h"
+
+#include "libipc/shm.h"
+
+#include "mmap_impl.h"
+
+LIBIPC_NAMESPACE_BEG_
+using namespace ::LIBIMP_;
+
+result<shm_t> shm_open(std::string name, std::size_t size, mode::type type) noexcept {
+  LIBIMP_LOG_();
+  auto h = mmap_open(name, size, type);
+  if (h == NULL) {
+    log.error("mmap_open failed.");
+    return {nullptr, *sys::error_code()};
+  }
+  auto mem = mmap_memof(h);
+  if (mem == NULL) {
+    log.warning("mmap_memof failed.");
+  }
+  return new shm_handle{std::move(name), mmap_sizeof(mem), mem, h};
+}
+
+result_code shm_close(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  mmap_release(shm->h_fmap, shm->memp);
+  delete shm;
+  return {true};
+}
+
+LIBIPC_NAMESPACE_END_

src/libipc/platform/win/to_tchar.h

@@ -1,3 +1,7 @@
+/**
+ * @file libipc/platform/win/to_tchar.h
+ * @author mutouyun (orz@orzz.org)
+ */
 #pragma once
 
 #include <tchar.h>

src/libipc/shm.cpp

@@ -3,9 +3,9 @@
 
 #include "libimp/detect_plat.h"
 #if defined(LIBIMP_OS_WIN)
-#include "libipc/platform/win/mmap.h"
+#include "libipc/platform/win/shm_impl.h"
 #else
-#include "libipc/platform/posix/mmap.h"
+#include "libipc/platform/posix/shm_impl.h"
 #endif
 
 LIBIPC_NAMESPACE_BEG_