| 1 | /*++ |
| 2 | |
| 3 | Copyright (c) Microsoft. All rights reserved. |
| 4 | |
| 5 | Module Name: |
| 6 | |
| 7 | select.c |
| 8 | |
| 9 | Abstract: |
| 10 | |
| 11 | This file is the select system call test. |
| 12 | |
| 13 | --*/ |
| 14 | |
| 15 | #include "lxtcommon.h" |
| 16 | #include "unittests.h" |
| 17 | #include <sys/select.h> |
| 18 | #include <sys/stat.h> |
| 19 | #include <sys/time.h> |
| 20 | #include <sys/resource.h> |
| 21 | #include <sys/types.h> |
| 22 | #include <sys/mman.h> |
| 23 | #include <unistd.h> |
| 24 | #include <fcntl.h> |
| 25 | #include <errno.h> |
| 26 | #include <stdlib.h> |
| 27 | |
| 28 | #if defined(__aarch64__) |
| 29 | |
| 30 | // |
| 31 | // ARM64 glibc converts select to pselect. |
| 32 | // |
| 33 | |
| 34 | #define __ARCH_WANT_SYSCALL_DEPRECATED |
| 35 | #include <linux/unistd.h> |
| 36 | #define SYS_select __NR_select |
| 37 | #endif |
| 38 | |
| 39 | #define LxtSelect(_nfds, _readfds, _writefds, _exceptfds, _timeout) \ |
| 40 | (syscall(SYS_select, _nfds, _readfds, _writefds, _exceptfds, _timeout)) |
| 41 | |
| 42 | #define LXT_NAME "Select" |
| 43 | #define LXT_SELECT_TEST_FILE "/data/test/select_test.bin" |
| 44 | #define LXT_SHORT_TIMEOUT 1 |
| 45 | |
| 46 | LXT_VARIATION_HANDLER SelectFdBufferSize; |
| 47 | LXT_VARIATION_HANDLER SelectMaxNfds; |
| 48 | |
| 49 | // |
| 50 | // Global constants |
| 51 | // |
| 52 | |
| 53 | static const LXT_VARIATION g_LxtVariations[] = {{"FD buffer sizes", SelectFdBufferSize}, {"Max nfds", SelectMaxNfds}}; |
| 54 | |
| 55 | int SelectTestEntry(int Argc, char* Argv[]) |
| 56 | |
| 57 | /*++ |
| 58 | --*/ |
| 59 | |
| 60 | { |
| 61 | |
| 62 | LXT_ARGS Args; |
| 63 | int Result; |
| 64 | |
| 65 | LxtCheckResult(LxtInitialize(Argc, Argv, &Args, LXT_NAME)); |
| 66 | LxtCheckResult(LxtRunVariations(&Args, g_LxtVariations, LXT_COUNT_OF(g_LxtVariations))); |
| 67 | |
| 68 | ErrorExit: |
| 69 | LxtUninitialize(); |
| 70 | return !LXT_SUCCESS(Result); |
| 71 | } |
| 72 | |
| 73 | int SelectFdBufferSize(PLXT_ARGS Args) |
| 74 | { |
| 75 | |
| 76 | unsigned char* Address; |
| 77 | int Fds[sizeof(unsigned long) * 8 * 2]; |
| 78 | int Index; |
| 79 | void* MapResult; |
| 80 | int Result; |
| 81 | fd_set* ReadSet; |
| 82 | unsigned char* ReadSetBuffer; |
| 83 | int ReadSetCount; |
| 84 | struct timeval Timeout; |
| 85 | |
| 86 | Address = NULL; |
| 87 | memset(Fds, -1, sizeof(Fds)); |
| 88 | Result = LXT_RESULT_FAILURE; |
| 89 | |
| 90 | // |
| 91 | // Open files that will be used for select. |
| 92 | // |
| 93 | |
| 94 | for (Index = 0; Index < LXT_COUNT_OF(Fds); ++Index) |
| 95 | { |
| 96 | LxtCheckErrno(Fds[Index] = open(LXT_SELECT_TEST_FILE, O_RDWR | O_CREAT, S_IRWXU)); |
| 97 | } |
| 98 | |
| 99 | // |
| 100 | // Create a read\write page followed by a no access page. The readset buffer |
| 101 | // will be adjusted so it is just before the no access page. |
| 102 | // |
| 103 | |
| 104 | LxtCheckMapErrno(Address = mmap(NULL, PAGE_SIZE * 2, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANONYMOUS), -1, 0)); |
| 105 | LxtCheckErrno(mprotect(Address + PAGE_SIZE, PAGE_SIZE, PROT_NONE)); |
| 106 | |
| 107 | // |
| 108 | // A ReadSetCount of 0 should not touch the buffer. |
| 109 | // |
| 110 | |
| 111 | ReadSetCount = 0; |
| 112 | ReadSetBuffer = (Address + PAGE_SIZE) - sizeof(unsigned char); |
| 113 | memset(ReadSetBuffer, -1, sizeof(unsigned char)); |
| 114 | ReadSet = (fd_set*)ReadSetBuffer; |
| 115 | memset(&Timeout, 0, sizeof(Timeout)); |
| 116 | LxtCheckErrno(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout)); |
| 117 | LxtCheckEqual(*ReadSetBuffer, (unsigned char)-1, "%c"); |
| 118 | |
| 119 | // |
| 120 | // Test select with different sized buffers that have all of the bits set |
| 121 | // and a ReadSetCount of 1. The expectation is that the write will fail if |
| 122 | // the buffer is less than an unsigned long. If larger, the values will be |
| 123 | // zeroed out to an unsigned long but not more. |
| 124 | // |
| 125 | |
| 126 | ReadSetCount = 1; |
| 127 | ReadSetBuffer = (Address + PAGE_SIZE) - sizeof(unsigned char); |
| 128 | memset(ReadSetBuffer, -1, sizeof(unsigned char)); |
| 129 | ReadSet = (fd_set*)ReadSetBuffer; |
| 130 | memset(&Timeout, 0, sizeof(Timeout)); |
| 131 | LxtCheckErrnoFailure(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout), EFAULT); |
| 132 | LxtCheckEqual(*ReadSetBuffer, (unsigned char)-1, "%c"); |
| 133 | |
| 134 | if (sizeof(unsigned int) != sizeof(unsigned long)) |
| 135 | { |
| 136 | ReadSetBuffer = (Address + PAGE_SIZE) - sizeof(unsigned int); |
| 137 | memset(ReadSetBuffer, -1, sizeof(unsigned int)); |
| 138 | ReadSet = (fd_set*)ReadSetBuffer; |
| 139 | memset(&Timeout, 0, sizeof(Timeout)); |
| 140 | LxtCheckErrnoFailure(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout), EFAULT); |
| 141 | LxtCheckEqual(*(unsigned int*)ReadSetBuffer, (unsigned int)-1, "%d"); |
| 142 | } |
| 143 | |
| 144 | ReadSetBuffer = (Address + PAGE_SIZE) - sizeof(unsigned long); |
| 145 | memset(ReadSetBuffer, -1, sizeof(unsigned long)); |
| 146 | ReadSet = (fd_set*)ReadSetBuffer; |
| 147 | memset(&Timeout, 0, sizeof(Timeout)); |
| 148 | LxtCheckErrno(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout)); |
| 149 | LxtCheckEqual(*((unsigned long*)ReadSetBuffer), 0, "%ld"); |
| 150 | |
| 151 | ReadSetBuffer = (Address + PAGE_SIZE) - (sizeof(unsigned long) * 2); |
| 152 | memset(ReadSetBuffer, -1, sizeof(unsigned long) * 2); |
| 153 | ReadSet = (fd_set*)ReadSetBuffer; |
| 154 | memset(&Timeout, 0, sizeof(Timeout)); |
| 155 | LxtCheckErrno(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout)); |
| 156 | LxtCheckEqual(*((unsigned long*)ReadSetBuffer), 0, "%ld"); |
| 157 | LxtCheckEqual(*(((unsigned long*)ReadSetBuffer + 1)), -1, "%ld"); |
| 158 | |
| 159 | // |
| 160 | // Test with a ReadSetCount of exactly the number of bits in an unsigned |
| 161 | // long. |
| 162 | // |
| 163 | |
| 164 | ReadSetCount = sizeof(unsigned long) * 8; |
| 165 | ReadSetBuffer = (Address + PAGE_SIZE) - (sizeof(unsigned long) * 2); |
| 166 | memset(ReadSetBuffer, -1, sizeof(unsigned long) * 2); |
| 167 | ReadSet = (fd_set*)ReadSetBuffer; |
| 168 | memset(&Timeout, 0, sizeof(Timeout)); |
| 169 | LxtCheckErrno(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout)); |
| 170 | LxtCheckNotEqual(*((unsigned long*)ReadSetBuffer), -1, "%ld"); |
| 171 | LxtCheckEqual(*(((unsigned long*)ReadSetBuffer + 1)), -1, "%ld"); |
| 172 | |
| 173 | // |
| 174 | // And again with one larger. |
| 175 | // |
| 176 | |
| 177 | ReadSetCount = sizeof(unsigned long) * 8 + 1; |
| 178 | ReadSetBuffer = (Address + PAGE_SIZE) - (sizeof(unsigned long) * 2); |
| 179 | memset(ReadSetBuffer, -1, sizeof(unsigned long) * 2); |
| 180 | ReadSet = (fd_set*)ReadSetBuffer; |
| 181 | memset(&Timeout, 0, sizeof(Timeout)); |
| 182 | LxtCheckErrno(LxtSelect(ReadSetCount, ReadSet, NULL, NULL, &Timeout)); |
| 183 | LxtCheckNotEqual(*((unsigned long*)ReadSetBuffer), -1, "%ld"); |
| 184 | LxtCheckEqual(*(((unsigned long*)ReadSetBuffer + 1)), 1, "%ld"); |
| 185 | |
| 186 | Result = LXT_RESULT_SUCCESS; |
| 187 | |
| 188 | ErrorExit: |
| 189 | for (Index = 0; Index < LXT_COUNT_OF(Fds); ++Index) |
| 190 | { |
| 191 | if (Fds[Index] != -1) |
| 192 | { |
| 193 | LxtClose(Fds[Index]); |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | if (Address != NULL) |
| 198 | { |
| 199 | munmap(Address, PAGE_SIZE * 2); |
| 200 | } |
| 201 | |
| 202 | return Result; |
| 203 | } |
| 204 | |
| 205 | int SelectMaxNfds(PLXT_ARGS Args) |
| 206 | { |
| 207 | |
| 208 | int Result; |
| 209 | int Fd; |
| 210 | int NumFd; |
| 211 | fd_set ReadSet; |
| 212 | struct timeval Timeout; |
| 213 | struct rlimit MaxFds; |
| 214 | |
| 215 | // |
| 216 | // Initialize locals. |
| 217 | // |
| 218 | |
| 219 | Fd = -1; |
| 220 | Timeout.tv_sec = 5; |
| 221 | Timeout.tv_usec = 0; |
| 222 | |
| 223 | // |
| 224 | // Open a file that will be used for select. |
| 225 | // |
| 226 | |
| 227 | LxtCheckErrno(Fd = open(LXT_SELECT_TEST_FILE, (O_RDWR | O_CREAT), S_IRWXU)); |
| 228 | |
| 229 | // |
| 230 | // Create the select set and set the FD in it. |
| 231 | // |
| 232 | |
| 233 | FD_ZERO(&ReadSet); |
| 234 | FD_SET(Fd, &ReadSet); |
| 235 | |
| 236 | // |
| 237 | // -ve values for 'nfds' should return EINVAL. |
| 238 | // |
| 239 | |
| 240 | LxtCheckErrnoFailure(select(-1, &ReadSet, NULL, NULL, &Timeout), EINVAL); |
| 241 | |
| 242 | LxtLogInfo("Waiting on select to succeed.."); |
| 243 | |
| 244 | // |
| 245 | // Set 'nfds' to > FD_SETSIZE. Kernel seems to ignore anything above the |
| 246 | // current ulimit(RLIMIT_NOFILE). |
| 247 | // |
| 248 | // N.B The value chosen for 'nfds' is > nr_open (which is the upper limit |
| 249 | // for RLIMIT_NOFILE and by default set to 1048576). As per the man |
| 250 | // page, EINVAL is returned if nfds exceeds the RLIMIT_NOFILE resource |
| 251 | // limit, but that doesn't seem to be case. |
| 252 | // |
| 253 | |
| 254 | LxtCheckErrno(NumFd = select(1048576 + 100, &ReadSet, NULL, NULL, &Timeout)); |
| 255 | |
| 256 | LxtCheckEqual(NumFd, 1, "%d"); |
| 257 | if (FD_ISSET(Fd, &ReadSet) == 0) |
| 258 | { |
| 259 | LxtLogError( |
| 260 | "Select was satisfied but file descriptor is not set " |
| 261 | "for read!"); |
| 262 | |
| 263 | Result = -1; |
| 264 | goto ErrorExit; |
| 265 | } |
| 266 | |
| 267 | // |
| 268 | // Provide a bad file descriptor to select. As per the man page kernel |
| 269 | // ignores any FD > maximum FD currently opened by the process. But, |
| 270 | // in testing it seems like it does perform that check. |
| 271 | // |
| 272 | // N.B Below assumes that 200 > #FD's opened by the process. |
| 273 | // |
| 274 | |
| 275 | FD_ZERO(&ReadSet); |
| 276 | FD_SET(200, &ReadSet); |
| 277 | |
| 278 | // |
| 279 | // Kernel ignores anything above FD_SETSIZE. |
| 280 | // |
| 281 | |
| 282 | LxtCheckErrnoFailure(select(201, &ReadSet, NULL, NULL, &Timeout), EBADF); |
| 283 | |
| 284 | Result = LXT_RESULT_SUCCESS; |
| 285 | |
| 286 | ErrorExit: |
| 287 | if (Fd != -1) |
| 288 | { |
| 289 | close(Fd); |
| 290 | } |
| 291 | |
| 292 | return Result; |
| 293 | } |