/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2.0, as published by the Free Software Foundation. This program is also distributed with certain software (including but not limited to OpenSSL) that is licensed under separate terms, as designated in a particular file or component or in included license documentation. The authors of MySQL hereby grant you an additional permission to link the program and your derivative works with the separately licensed software that they have included with MySQL. Without limiting anything contained in the foregoing, this file, which is part of C Driver for MySQL (Connector/C), is also subject to the Universal FOSS Exception, version 1.0, a copy of which can be found at http://oss.oracle.com/licenses/universal-foss-exception. 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, version 2.0, for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /** @file mysys/my_write.cc */ #include "my_config.h" #include #include #include #ifdef HAVE_UNISTD_H #include #endif #include "my_compiler.h" #include "my_dbug.h" #include "my_inttypes.h" #include "my_io.h" #include "my_sys.h" #include "my_thread_local.h" #include "mysys_err.h" #if defined(_WIN32) #include "mysys/mysys_priv.h" #endif #include extern PSI_stage_info stage_waiting_for_disk_space; #ifndef _WIN32 // Mock away write() for unit testing. ssize_t (*mock_write)(int fd, const void *buf, size_t count) = nullptr; #endif /** Write a chunk of bytes to a file if (MyFlags & (MY_NABP | MY_FNABP)) returns 0 if Count == 0 On succes, 0 On failure, (size_t)-1 == MY_FILE_ERROR otherwise returns 0 if Count == 0 On success, the number of bytes written. On partial success (if less than Count bytes could be written), the actual number of bytes written. On failure, (size_t)-1 == MY_FILE_ERROR */ size_t my_write(File Filedes, const uchar *Buffer, size_t Count, myf MyFlags) { size_t writtenbytes; size_t sum_written = 0; uint errors = 0; const size_t initial_count = Count; size_t ToWriteCount; DBUG_TRACE; DBUG_PRINT("my", ("fd: %d Buffer: %p Count: %lu MyFlags: %d", Filedes, Buffer, (ulong)Count, MyFlags)); /* The behavior of write(fd, buf, 0) is not portable */ if (unlikely(!Count)) return 0; DBUG_EXECUTE_IF("simulate_no_free_space_error", { DBUG_SET("+d,simulate_file_write_error"); }); for (;;) { errno = 0; ToWriteCount = Count; DBUG_EXECUTE_IF("force_wait_for_disk_space", { ToWriteCount = 1; }); DBUG_EXECUTE_IF("simulate_io_thd_wait_for_disk_space", { if (strstr(my_filename(Filedes), "slave-relay-bin.0")) ToWriteCount = 1; }); DBUG_EXECUTE_IF("simulate_random_io_thd_wait_for_disk_space", { if (strstr(my_filename(Filedes), "slave-relay-bin.0")) { if (rand() % 3 == 0) ToWriteCount = Count; else ToWriteCount = std::min(Count, 1 + (Count * (rand() % 100) / 100)); } }); #ifdef _WIN32 writtenbytes = my_win_write(Filedes, Buffer, ToWriteCount); #else if (mock_write) writtenbytes = mock_write(Filedes, Buffer, ToWriteCount); else writtenbytes = write(Filedes, Buffer, ToWriteCount); #endif DBUG_EXECUTE_IF("simulate_file_write_error", { errno = ENOSPC; writtenbytes = (size_t)-1; }); DBUG_EXECUTE_IF("force_wait_for_disk_space", { errno = ENOSPC; }); DBUG_EXECUTE_IF("simulate_io_thd_wait_for_disk_space", { if (strstr(my_filename(Filedes), "slave-relay-bin.0")) errno = ENOSPC; }); DBUG_EXECUTE_IF("simulate_random_io_thd_wait_for_disk_space", { if (strstr(my_filename(Filedes), "slave-relay-bin.0") && ToWriteCount != Count) errno = ENOSPC; }); if (writtenbytes == Count) { sum_written += writtenbytes; break; } if (writtenbytes != (size_t)-1) { /* Safeguard */ sum_written += writtenbytes; Buffer += writtenbytes; Count -= writtenbytes; } set_my_errno(errno); DBUG_PRINT("error", ("Write only %ld bytes, error: %d", (long)writtenbytes, my_errno())); if (is_killed_hook(NULL)) MyFlags &= ~MY_WAIT_IF_FULL; /* End if aborted by user */ if ((my_errno() == ENOSPC || my_errno() == EDQUOT) && (MyFlags & MY_WAIT_IF_FULL)) { PSI_stage_info old_stage; if (MyFlags & MY_REPORT_WAITING_IF_FULL) { set_waiting_for_disk_space_hook(NULL, true); enter_stage_hook(NULL, &stage_waiting_for_disk_space, &old_stage, __func__, __FILE__, __LINE__); } wait_for_free_space(my_filename(Filedes), errors); if (MyFlags & MY_REPORT_WAITING_IF_FULL) { enter_stage_hook(NULL, &old_stage, NULL, __func__, __FILE__, __LINE__); set_waiting_for_disk_space_hook(NULL, false); } errors++; DBUG_EXECUTE_IF("simulate_no_free_space_error", { DBUG_SET("-d,simulate_file_write_error"); }); if (is_killed_hook(NULL)) break; continue; } if (writtenbytes != 0 && writtenbytes != (size_t)-1 && !is_killed_hook(NULL)) continue; /* Retry if something written */ else if (my_errno() == EINTR) { DBUG_PRINT("debug", ("my_write() was interrupted and returned %ld", (long)writtenbytes)); continue; /* Interrupted, retry */ } else if (writtenbytes == 0 && !errors++) /* Retry once */ { /* We may come here if the file quota is exeeded */ continue; } break; } if (MyFlags & (MY_NABP | MY_FNABP)) { if (sum_written == initial_count) return 0; /* Want only errors, not bytes written */ if (MyFlags & (MY_WME | MY_FAE | MY_FNABP)) { char errbuf[MYSYS_STRERROR_SIZE]; my_error(EE_WRITE, MYF(0), my_filename(Filedes), my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno())); } return MY_FILE_ERROR; } if (sum_written == 0) return MY_FILE_ERROR; return sum_written; } /* my_write */