| 1 | /* |
| 2 | * SPDX-License-Identifier: MIT |
| 3 | * |
| 4 | * Copyright 2015 (c) Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 5 | * |
| 6 | * fcntl compatibility layer. |
| 7 | */ |
| 8 | |
| 9 | #ifndef _BABELTRACE_COMPAT_FCNTL_H |
| 10 | #define _BABELTRACE_COMPAT_FCNTL_H |
| 11 | |
| 12 | #include "common/common.h" |
| 13 | |
| 14 | #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE |
| 15 | |
| 16 | #include <fcntl.h> |
| 17 | |
| 18 | static inline |
| 19 | int bt_posix_fallocate(int fd, off_t offset, off_t len) |
| 20 | { |
| 21 | return posix_fallocate(fd, offset, len); |
| 22 | } |
| 23 | |
| 24 | #elif defined(__MINGW32__) /* #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE */ |
| 25 | |
| 26 | #include <stdlib.h> |
| 27 | #include <windows.h> |
| 28 | #include <fcntl.h> |
| 29 | |
| 30 | static inline |
| 31 | int bt_posix_fallocate(int fd, off_t offset, off_t len) |
| 32 | { |
| 33 | HANDLE handle; |
| 34 | LARGE_INTEGER pos, file_pos, orig_end_offset, range_end; |
| 35 | int ret = 0; |
| 36 | char zero = 0; |
| 37 | DWORD byteswritten; |
| 38 | |
| 39 | if (offset < 0 || len <= 0) { |
| 40 | ret = EINVAL; |
| 41 | goto end; |
| 42 | } |
| 43 | |
| 44 | range_end.QuadPart = (__int64) offset + (__int64) len; |
| 45 | |
| 46 | /* Get a handle from the fd */ |
| 47 | handle = (HANDLE) _get_osfhandle(fd); |
| 48 | if (handle == INVALID_HANDLE_VALUE) { |
| 49 | ret = EBADF; |
| 50 | goto end; |
| 51 | } |
| 52 | |
| 53 | /* Get the file original end offset */ |
| 54 | ret = GetFileSizeEx(handle, &orig_end_offset); |
| 55 | if (ret == 0) { |
| 56 | ret = EBADF; |
| 57 | goto end; |
| 58 | } |
| 59 | |
| 60 | /* Make sure we don't truncate the file */ |
| 61 | if (orig_end_offset.QuadPart >= range_end.QuadPart) { |
| 62 | ret = 0; |
| 63 | goto end; |
| 64 | } |
| 65 | |
| 66 | /* Get the current file pointer position */ |
| 67 | pos.QuadPart = 0; |
| 68 | ret = SetFilePointerEx(handle, pos, &file_pos, FILE_CURRENT); |
| 69 | if (ret == 0) { |
| 70 | ret = EBADF; |
| 71 | goto end; |
| 72 | } |
| 73 | |
| 74 | /* Move the file pointer to the new end offset */ |
| 75 | ret = SetFilePointerEx(handle, range_end, NULL, FILE_BEGIN); |
| 76 | if (ret == 0) { |
| 77 | ret = EBADF; |
| 78 | goto end; |
| 79 | } |
| 80 | |
| 81 | /* Sets the physical file size to the current position */ |
| 82 | ret = SetEndOfFile(handle); |
| 83 | if (ret == 0) { |
| 84 | ret = EINVAL; |
| 85 | goto restore; |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Move the file pointer back 1 byte, and write a single 0 at the |
| 90 | * last byte of the new end offset, the operating system will zero |
| 91 | * fill the file. |
| 92 | */ |
| 93 | pos.QuadPart = -1; |
| 94 | ret = SetFilePointerEx(handle, pos, NULL, FILE_END); |
| 95 | if (ret == 0) { |
| 96 | ret = EBADF; |
| 97 | goto end; |
| 98 | } |
| 99 | |
| 100 | ret = WriteFile(handle, &zero, 1, &byteswritten, NULL); |
| 101 | if (ret == 0 || byteswritten != 1) { |
| 102 | ret = ENOSPC; |
| 103 | } else { |
| 104 | ret = 0; |
| 105 | } |
| 106 | |
| 107 | restore: |
| 108 | /* Restore the original file pointer position */ |
| 109 | if (!SetFilePointerEx(handle, file_pos, NULL, FILE_BEGIN)) { |
| 110 | /* We moved the file pointer but failed to restore it. */ |
| 111 | bt_common_abort(); |
| 112 | } |
| 113 | |
| 114 | end: |
| 115 | return ret; |
| 116 | } |
| 117 | |
| 118 | #else |
| 119 | |
| 120 | #include <sys/types.h> |
| 121 | #include <unistd.h> |
| 122 | #include <string.h> |
| 123 | |
| 124 | #define BABELTRACE_FALLOCATE_BUFLEN 256 |
| 125 | |
| 126 | #ifndef min_t |
| 127 | #define min_t(type, a, b) \ |
| 128 | ((type) (a) < (type) (b) ? (type) (a) : (type) (b)) |
| 129 | #endif |
| 130 | |
| 131 | static inline |
| 132 | int bt_posix_fallocate(int fd, off_t offset, off_t len) |
| 133 | { |
| 134 | int ret = 0; |
| 135 | ssize_t copy_len; |
| 136 | char buf[BABELTRACE_FALLOCATE_BUFLEN]; |
| 137 | off_t i, file_pos, orig_end_offset, range_end; |
| 138 | |
| 139 | if (offset < 0 || len < 0) { |
| 140 | ret = EINVAL; |
| 141 | goto end; |
| 142 | } |
| 143 | |
| 144 | range_end = offset + len; |
| 145 | if (range_end < 0) { |
| 146 | ret = EFBIG; |
| 147 | goto end; |
| 148 | } |
| 149 | |
| 150 | file_pos = lseek(fd, 0, SEEK_CUR); |
| 151 | if (file_pos < 0) { |
| 152 | ret = errno; |
| 153 | goto end; |
| 154 | } |
| 155 | |
| 156 | orig_end_offset = lseek(fd, 0, SEEK_END); |
| 157 | if (orig_end_offset < 0) { |
| 158 | ret = errno; |
| 159 | goto end; |
| 160 | } |
| 161 | |
| 162 | /* Seek back to original position. */ |
| 163 | ret = lseek(fd, file_pos, SEEK_SET); |
| 164 | if (ret) { |
| 165 | ret = errno; |
| 166 | goto end; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * The file may not need to grow, but we want to ensure the |
| 171 | * space has actually been reserved by the file system. First, copy |
| 172 | * the "existing" region of the file, then grow the file if needed. |
| 173 | */ |
| 174 | for (i = file_pos; i < min_t(off_t, range_end, orig_end_offset); |
| 175 | i += copy_len) { |
| 176 | ssize_t copy_ret; |
| 177 | |
| 178 | copy_len = min_t(size_t, BABELTRACE_FALLOCATE_BUFLEN, |
| 179 | min_t(off_t, range_end - i, |
| 180 | orig_end_offset - i)); |
| 181 | copy_ret = pread(fd, &buf, copy_len, i); |
| 182 | if (copy_ret < copy_len) { |
| 183 | /* |
| 184 | * The caller must handle any EINTR. |
| 185 | * POSIX_FALLOCATE(3) does not mention EINTR. |
| 186 | * However, glibc does forward to fallocate() |
| 187 | * directly on Linux, which may be interrupted. |
| 188 | */ |
| 189 | ret = errno; |
| 190 | goto end; |
| 191 | } |
| 192 | |
| 193 | copy_ret = pwrite(fd, &buf, copy_len, i); |
| 194 | if (copy_ret < copy_len) { |
| 195 | /* Same caveat as noted at pread() */ |
| 196 | ret = errno; |
| 197 | goto end; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /* Grow file, as necessary. */ |
| 202 | memset(&buf, 0, BABELTRACE_FALLOCATE_BUFLEN); |
| 203 | for (i = orig_end_offset; i < range_end; i += copy_len) { |
| 204 | ssize_t write_ret; |
| 205 | |
| 206 | copy_len = min_t(size_t, BABELTRACE_FALLOCATE_BUFLEN, |
| 207 | range_end - i); |
| 208 | write_ret = pwrite(fd, &buf, copy_len, i); |
| 209 | if (write_ret < copy_len) { |
| 210 | ret = errno; |
| 211 | goto end; |
| 212 | } |
| 213 | } |
| 214 | end: |
| 215 | return ret; |
| 216 | } |
| 217 | #endif /* #else #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE */ |
| 218 | |
| 219 | #endif /* _BABELTRACE_COMPAT_FCNTL_H */ |