util: add safe write functions (#22160)

* add safe write functions

* log error

* bzfile safe_fopen&safe_flush

* update test_case

* trigger ci

Co-authored-by: Willem Melching <willem.melching@gmail.com>
old-commit-hash: 652c42da2c

selfdrive/common/tests/test_util.cc

@@ -93,6 +93,24 @@ TEST_CASE("util::read_files_in_dir") {
   }
 }
 
+
+TEST_CASE("util::safe_fwrite") {
+  char filename[] = "/tmp/XXXXXX";
+  int fd = mkstemp(filename);
+  close(fd);
+  std::string dat = random_bytes(1024 * 1024);
+
+  FILE *f = util::safe_fopen(filename, "wb");
+  REQUIRE(f != nullptr);
+  size_t size = util::safe_fwrite(dat.data(), 1, dat.size(), f);
+  REQUIRE(size == dat.size());
+  int ret = util::safe_fflush(f);
+  REQUIRE(ret == 0);
+  ret = fclose(f);
+  REQUIRE(ret == 0);
+  REQUIRE(dat == util::read_file(filename));
+}
+
 TEST_CASE("util::create_directories") {
   system("rm /tmp/test_create_directories -rf");
   std::string dir = "/tmp/test_create_directories/a/b/c/d/e/f";

selfdrive/common/util.cc

@@ -107,6 +107,32 @@ int write_file(const char* path, const void* data, size_t size, int flags, mode_
   return (n >= 0 && (size_t)n == size) ? 0 : -1;
 }
 
+FILE* safe_fopen(const char* filename, const char* mode) {
+  FILE* fp = NULL;
+  do {
+    fp = fopen(filename, mode);
+  } while ((nullptr == fp) && (errno == EINTR));
+  return fp;
+}
+
+size_t safe_fwrite(const void* ptr, size_t size, size_t count, FILE* stream) {
+  size_t written = 0;
+  do {
+    size_t ret = ::fwrite((void*)((char *)ptr + written * size), size, count - written, stream);
+    if (ret == 0 && errno != EINTR) break;
+    written += ret;
+  } while (written != count);
+  return written;
+}
+
+int safe_fflush(FILE *stream) {
+  int ret = EOF;
+  do {
+    ret = fflush(stream);
+  } while ((EOF == ret) && (errno == EINTR));
+  return ret;
+}
+
 std::string readlink(const std::string &path) {
   char buff[4096];
   ssize_t len = ::readlink(path.c_str(), buff, sizeof(buff)-1);

selfdrive/common/util.h

@@ -75,6 +75,11 @@ std::string dir_name(std::string const& path);
 std::string read_file(const std::string& fn);
 std::map<std::string, std::string> read_files_in_dir(const std::string& path);
 int write_file(const char* path, const void* data, size_t size, int flags = O_WRONLY, mode_t mode = 0664);
+
+FILE* safe_fopen(const char* filename, const char* mode);
+size_t safe_fwrite(const void * ptr, size_t size, size_t count, FILE * stream);
+int safe_fflush(FILE *stream);
+
 std::string readlink(const std::string& path);
 bool file_exists(const std::string& fn);
 bool create_directories(const std::string &dir, mode_t mode);