base/strings/safe_sprintf_unittest.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/strings/safe_sprintf.h"
   6
   7 #include <stdio.h>
   8 #include <string.h>
   9
  10 #include <limits>
  11
  12 #include "base/logging.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "testing/gtest/include/gtest/gtest.h"
  15
  16 // Death tests on Android are currently very flaky. No need to add more flaky
  17 // tests, as they just make it hard to spot real problems.
  18 // TODO(markus): See if the restrictions on Android can eventually be lifted.
  19 #if defined(GTEST_HAS_DEATH_TEST) && !defined(OS_ANDROID)
  20 #define ALLOW_DEATH_TEST
  21 #endif
  22
  23 namespace base {
  24 namespace strings {
  25
  26 TEST(SafeSPrintfTest, Empty) {
  27   char buf[2] = { 'X', 'X' };
  28
  29   // Negative buffer size should always result in an error.
  30   EXPECT_EQ(-1, SafeSNPrintf(buf, -1, ""));
  31   EXPECT_EQ('X', buf[0]);
  32   EXPECT_EQ('X', buf[1]);
  33
  34   // Zero buffer size should always result in an error.
  35   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, ""));
  36   EXPECT_EQ('X', buf[0]);
  37   EXPECT_EQ('X', buf[1]);
  38
  39   // A one-byte buffer should always print a single NUL byte.
  40   EXPECT_EQ(0, SafeSNPrintf(buf, 1, ""));
  41   EXPECT_EQ(0, buf[0]);
  42   EXPECT_EQ('X', buf[1]);
  43   buf[0] = 'X';
  44
  45   // A larger buffer should leave the trailing bytes unchanged.
  46   EXPECT_EQ(0, SafeSNPrintf(buf, 2, ""));
  47   EXPECT_EQ(0, buf[0]);
  48   EXPECT_EQ('X', buf[1]);
  49   buf[0] = 'X';
  50
  51   // The same test using SafeSPrintf() instead of SafeSNPrintf().
  52   EXPECT_EQ(0, SafeSPrintf(buf, ""));
  53   EXPECT_EQ(0, buf[0]);
  54   EXPECT_EQ('X', buf[1]);
  55   buf[0] = 'X';
  56 }
  57
  58 TEST(SafeSPrintfTest, NoArguments) {
  59   // Output a text message that doesn't require any substitutions. This
  60   // is roughly equivalent to calling strncpy() (but unlike strncpy(), it does
  61   // always add a trailing NUL; it always deduplicates '%' characters).
  62   static const char text[] = "hello world";
  63   char ref[20], buf[20];
  64   memset(ref, 'X', sizeof(char) * arraysize(buf));
  65   memcpy(buf, ref, sizeof(buf));
  66
  67   // A negative buffer size should always result in an error.
  68   EXPECT_EQ(-1, SafeSNPrintf(buf, -1, text));
  69   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
  70
  71   // Zero buffer size should always result in an error.
  72   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, text));
  73   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
  74
  75   // A one-byte buffer should always print a single NUL byte.
  76   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 1, text));
  77   EXPECT_EQ(0, buf[0]);
  78   EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
  79   memcpy(buf, ref, sizeof(buf));
  80
  81   // A larger (but limited) buffer should always leave the trailing bytes
  82   // unchanged.
  83   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSNPrintf(buf, 2, text));
  84   EXPECT_EQ(text[0], buf[0]);
  85   EXPECT_EQ(0, buf[1]);
  86   EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
  87   memcpy(buf, ref, sizeof(buf));
  88
  89   // A unrestricted buffer length should always leave the trailing bytes
  90   // unchanged.
  91   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
  92             SafeSNPrintf(buf, sizeof(buf), text));
  93   EXPECT_EQ(std::string(text), std::string(buf));
  94   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
  95                       sizeof(buf) - sizeof(text)));
  96   memcpy(buf, ref, sizeof(buf));
  97
  98   // The same test using SafeSPrintf() instead of SafeSNPrintf().
  99   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, text));
 100   EXPECT_EQ(std::string(text), std::string(buf));
 101   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
 102                       sizeof(buf) - sizeof(text)));
 103   memcpy(buf, ref, sizeof(buf));
 104
 105   // Check for deduplication of '%' percent characters.
 106   EXPECT_EQ(1, SafeSPrintf(buf, "%%"));
 107   EXPECT_EQ(2, SafeSPrintf(buf, "%%%%"));
 108   EXPECT_EQ(2, SafeSPrintf(buf, "%%X"));
 109   EXPECT_EQ(3, SafeSPrintf(buf, "%%%%X"));
 110 #if defined(NDEBUG)
 111   EXPECT_EQ(1, SafeSPrintf(buf, "%"));
 112   EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
 113   EXPECT_EQ(2, SafeSPrintf(buf, "%X"));
 114   EXPECT_EQ(3, SafeSPrintf(buf, "%%%X"));
 115 #elif defined(ALLOW_DEATH_TEST)
 116   EXPECT_DEATH(SafeSPrintf(buf, "%"), "src.1. == '%'");
 117   EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
 118   EXPECT_DEATH(SafeSPrintf(buf, "%X"), "src.1. == '%'");
 119   EXPECT_DEATH(SafeSPrintf(buf, "%%%X"), "src.1. == '%'");
 120 #endif
 121 }
 122
 123 TEST(SafeSPrintfTest, OneArgument) {
 124   // Test basic single-argument single-character substitution.
 125   const char text[] = "hello world";
 126   const char fmt[]  = "hello%cworld";
 127   char ref[20], buf[20];
 128   memset(ref, 'X', sizeof(buf));
 129   memcpy(buf, ref, sizeof(buf));
 130
 131   // A negative buffer size should always result in an error.
 132   EXPECT_EQ(-1, SafeSNPrintf(buf, -1, fmt, ' '));
 133   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
 134
 135   // Zero buffer size should always result in an error.
 136   EXPECT_EQ(-1, SafeSNPrintf(buf, 0, fmt, ' '));
 137   EXPECT_TRUE(!memcmp(buf, ref, sizeof(buf)));
 138
 139   // A one-byte buffer should always print a single NUL byte.
 140   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
 141             SafeSNPrintf(buf, 1, fmt, ' '));
 142   EXPECT_EQ(0, buf[0]);
 143   EXPECT_TRUE(!memcmp(buf+1, ref+1, sizeof(buf)-1));
 144   memcpy(buf, ref, sizeof(buf));
 145
 146   // A larger (but limited) buffer should always leave the trailing bytes
 147   // unchanged.
 148   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
 149             SafeSNPrintf(buf, 2, fmt, ' '));
 150   EXPECT_EQ(text[0], buf[0]);
 151   EXPECT_EQ(0, buf[1]);
 152   EXPECT_TRUE(!memcmp(buf+2, ref+2, sizeof(buf)-2));
 153   memcpy(buf, ref, sizeof(buf));
 154
 155   // A unrestricted buffer length should always leave the trailing bytes
 156   // unchanged.
 157   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1,
 158             SafeSNPrintf(buf, sizeof(buf), fmt, ' '));
 159   EXPECT_EQ(std::string(text), std::string(buf));
 160   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
 161                       sizeof(buf) - sizeof(text)));
 162   memcpy(buf, ref, sizeof(buf));
 163
 164   // The same test using SafeSPrintf() instead of SafeSNPrintf().
 165   EXPECT_EQ(static_cast<ssize_t>(sizeof(text))-1, SafeSPrintf(buf, fmt, ' '));
 166   EXPECT_EQ(std::string(text), std::string(buf));
 167   EXPECT_TRUE(!memcmp(buf + sizeof(text), ref + sizeof(text),
 168                       sizeof(buf) - sizeof(text)));
 169   memcpy(buf, ref, sizeof(buf));
 170
 171   // Check for deduplication of '%' percent characters.
 172   EXPECT_EQ(1, SafeSPrintf(buf, "%%", 0));
 173   EXPECT_EQ(2, SafeSPrintf(buf, "%%%%", 0));
 174   EXPECT_EQ(2, SafeSPrintf(buf, "%Y", 0));
 175   EXPECT_EQ(2, SafeSPrintf(buf, "%%Y", 0));
 176   EXPECT_EQ(3, SafeSPrintf(buf, "%%%Y", 0));
 177   EXPECT_EQ(3, SafeSPrintf(buf, "%%%%Y", 0));
 178 #if defined(NDEBUG)
 179   EXPECT_EQ(1, SafeSPrintf(buf, "%", 0));
 180   EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
 181 #elif defined(ALLOW_DEATH_TEST)
 182   EXPECT_DEATH(SafeSPrintf(buf, "%", 0), "ch");
 183   EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
 184 #endif
 185 }
 186
 187 TEST(SafeSPrintfTest, MissingArg) {
 188 #if defined(NDEBUG)
 189   char buf[20];
 190   EXPECT_EQ(3, SafeSPrintf(buf, "%c%c", 'A'));
 191   EXPECT_EQ("A%c", std::string(buf));
 192 #elif defined(ALLOW_DEATH_TEST)
 193   char buf[20];
 194   EXPECT_DEATH(SafeSPrintf(buf, "%c%c", 'A'), "cur_arg < max_args");
 195 #endif
 196 }
 197
 198 TEST(SafeSPrintfTest, ASANFriendlyBufferTest) {
 199   // Print into a buffer that is sized exactly to size. ASAN can verify that
 200   // nobody attempts to write past the end of the buffer.
 201   // There is a more complicated test in PrintLongString() that covers a lot
 202   // more edge case, but it is also harder to debug in case of a failure.
 203   const char kTestString[] = "This is a test";
 204   scoped_ptr<char[]> buf(new char[sizeof(kTestString)]);
 205   EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
 206             SafeSNPrintf(buf.get(), sizeof(kTestString), kTestString));
 207   EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
 208   EXPECT_EQ(static_cast<ssize_t>(sizeof(kTestString) - 1),
 209             SafeSNPrintf(buf.get(), sizeof(kTestString), "%s", kTestString));
 210   EXPECT_EQ(std::string(kTestString), std::string(buf.get()));
 211 }
 212
 213 TEST(SafeSPrintfTest, NArgs) {
 214   // Pre-C++11 compilers have a different code path, that can only print
 215   // up to ten distinct arguments.
 216   // We test both SafeSPrintf() and SafeSNPrintf(). This makes sure we don't
 217   // have typos in the copy-n-pasted code that is needed to deal with various
 218   // numbers of arguments.
 219   char buf[12];
 220   EXPECT_EQ(1, SafeSPrintf(buf, "%c", 1));
 221   EXPECT_EQ("\1", std::string(buf));
 222   EXPECT_EQ(2, SafeSPrintf(buf, "%c%c", 1, 2));
 223   EXPECT_EQ("\1\2", std::string(buf));
 224   EXPECT_EQ(3, SafeSPrintf(buf, "%c%c%c", 1, 2, 3));
 225   EXPECT_EQ("\1\2\3", std::string(buf));
 226   EXPECT_EQ(4, SafeSPrintf(buf, "%c%c%c%c", 1, 2, 3, 4));
 227   EXPECT_EQ("\1\2\3\4", std::string(buf));
 228   EXPECT_EQ(5, SafeSPrintf(buf, "%c%c%c%c%c", 1, 2, 3, 4, 5));
 229   EXPECT_EQ("\1\2\3\4\5", std::string(buf));
 230   EXPECT_EQ(6, SafeSPrintf(buf, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
 231   EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
 232   EXPECT_EQ(7, SafeSPrintf(buf, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
 233   EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
 234   EXPECT_EQ(8, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7, 8));
 235   EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
 236   EXPECT_EQ(9, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c",
 237                            1, 2, 3, 4, 5, 6, 7, 8, 9));
 238   EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
 239   EXPECT_EQ(10, SafeSPrintf(buf, "%c%c%c%c%c%c%c%c%c%c",
 240                             1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
 241
 242   // Repeat all the tests with SafeSNPrintf() instead of SafeSPrintf().
 243   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
 244   EXPECT_EQ(1, SafeSNPrintf(buf, 11, "%c", 1));
 245   EXPECT_EQ("\1", std::string(buf));
 246   EXPECT_EQ(2, SafeSNPrintf(buf, 11, "%c%c", 1, 2));
 247   EXPECT_EQ("\1\2", std::string(buf));
 248   EXPECT_EQ(3, SafeSNPrintf(buf, 11, "%c%c%c", 1, 2, 3));
 249   EXPECT_EQ("\1\2\3", std::string(buf));
 250   EXPECT_EQ(4, SafeSNPrintf(buf, 11, "%c%c%c%c", 1, 2, 3, 4));
 251   EXPECT_EQ("\1\2\3\4", std::string(buf));
 252   EXPECT_EQ(5, SafeSNPrintf(buf, 11, "%c%c%c%c%c", 1, 2, 3, 4, 5));
 253   EXPECT_EQ("\1\2\3\4\5", std::string(buf));
 254   EXPECT_EQ(6, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6));
 255   EXPECT_EQ("\1\2\3\4\5\6", std::string(buf));
 256   EXPECT_EQ(7, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c", 1, 2, 3, 4, 5, 6, 7));
 257   EXPECT_EQ("\1\2\3\4\5\6\7", std::string(buf));
 258   EXPECT_EQ(8, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c",
 259                             1, 2, 3, 4, 5, 6, 7, 8));
 260   EXPECT_EQ("\1\2\3\4\5\6\7\10", std::string(buf));
 261   EXPECT_EQ(9, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c",
 262                             1, 2, 3, 4, 5, 6, 7, 8, 9));
 263   EXPECT_EQ("\1\2\3\4\5\6\7\10\11", std::string(buf));
 264   EXPECT_EQ(10, SafeSNPrintf(buf, 11, "%c%c%c%c%c%c%c%c%c%c",
 265                              1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
 266   EXPECT_EQ("\1\2\3\4\5\6\7\10\11\12", std::string(buf));
 267 }
 268
 269 TEST(SafeSPrintfTest, DataTypes) {
 270   char buf[40];
 271
 272   // Bytes
 273   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint8_t)1));
 274   EXPECT_EQ("1", std::string(buf));
 275   EXPECT_EQ(3, SafeSPrintf(buf, "%d", (uint8_t)-1));
 276   EXPECT_EQ("255", std::string(buf));
 277   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int8_t)1));
 278   EXPECT_EQ("1", std::string(buf));
 279   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int8_t)-1));
 280   EXPECT_EQ("-1", std::string(buf));
 281   EXPECT_EQ(4, SafeSPrintf(buf, "%d", (int8_t)-128));
 282   EXPECT_EQ("-128", std::string(buf));
 283
 284   // Half-words
 285   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint16_t)1));
 286   EXPECT_EQ("1", std::string(buf));
 287   EXPECT_EQ(5, SafeSPrintf(buf, "%d", (uint16_t)-1));
 288   EXPECT_EQ("65535", std::string(buf));
 289   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int16_t)1));
 290   EXPECT_EQ("1", std::string(buf));
 291   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int16_t)-1));
 292   EXPECT_EQ("-1", std::string(buf));
 293   EXPECT_EQ(6, SafeSPrintf(buf, "%d", (int16_t)-32768));
 294   EXPECT_EQ("-32768", std::string(buf));
 295
 296   // Words
 297   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint32_t)1));
 298   EXPECT_EQ("1", std::string(buf));
 299   EXPECT_EQ(10, SafeSPrintf(buf, "%d", (uint32_t)-1));
 300   EXPECT_EQ("4294967295", std::string(buf));
 301   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int32_t)1));
 302   EXPECT_EQ("1", std::string(buf));
 303   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int32_t)-1));
 304   EXPECT_EQ("-1", std::string(buf));
 305   // Work-around for an limitation of C90
 306   EXPECT_EQ(11, SafeSPrintf(buf, "%d", (int32_t)-2147483647-1));
 307   EXPECT_EQ("-2147483648", std::string(buf));
 308
 309   // Quads
 310   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (uint64_t)1));
 311   EXPECT_EQ("1", std::string(buf));
 312   EXPECT_EQ(20, SafeSPrintf(buf, "%d", (uint64_t)-1));
 313   EXPECT_EQ("18446744073709551615", std::string(buf));
 314   EXPECT_EQ(1, SafeSPrintf(buf, "%d", (int64_t)1));
 315   EXPECT_EQ("1", std::string(buf));
 316   EXPECT_EQ(2, SafeSPrintf(buf, "%d", (int64_t)-1));
 317   EXPECT_EQ("-1", std::string(buf));
 318   // Work-around for an limitation of C90
 319   EXPECT_EQ(20, SafeSPrintf(buf, "%d", (int64_t)-9223372036854775807LL-1));
 320   EXPECT_EQ("-9223372036854775808", std::string(buf));
 321
 322   // Strings (both const and mutable).
 323   EXPECT_EQ(4, SafeSPrintf(buf, "test"));
 324   EXPECT_EQ("test", std::string(buf));
 325   EXPECT_EQ(4, SafeSPrintf(buf, buf));
 326   EXPECT_EQ("test", std::string(buf));
 327
 328   // Pointer
 329   char addr[20];
 330   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
 331   SafeSPrintf(buf, "%p", buf);
 332   EXPECT_EQ(std::string(addr), std::string(buf));
 333   SafeSPrintf(buf, "%p", (const char *)buf);
 334   EXPECT_EQ(std::string(addr), std::string(buf));
 335   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)sprintf);
 336   SafeSPrintf(buf, "%p", sprintf);
 337   EXPECT_EQ(std::string(addr), std::string(buf));
 338
 339   // Padding for pointers is a little more complicated because of the "0x"
 340   // prefix. Padding with '0' zeros is relatively straight-forward, but
 341   // padding with ' ' spaces requires more effort.
 342   sprintf(addr, "0x%017llX", (unsigned long long)(uintptr_t)buf);
 343   SafeSPrintf(buf, "%019p", buf);
 344   EXPECT_EQ(std::string(addr), std::string(buf));
 345   sprintf(addr, "0x%llX", (unsigned long long)(uintptr_t)buf);
 346   memset(addr, ' ',
 347          (char*)memmove(addr + sizeof(addr) - strlen(addr) - 1,
 348                         addr, strlen(addr)+1) - addr);
 349   SafeSPrintf(buf, "%19p", buf);
 350   EXPECT_EQ(std::string(addr), std::string(buf));
 351 }
 352
 353 namespace {
 354 void PrintLongString(char* buf, size_t sz) {
 355   // Output a reasonably complex expression into a limited-size buffer.
 356   // At least one byte is available for writing the NUL character.
 357   CHECK_GT(sz, static_cast<size_t>(0));
 358
 359   // Allocate slightly more space, so that we can verify that SafeSPrintf()
 360   // never writes past the end of the buffer.
 361   scoped_ptr<char[]> tmp(new char[sz+2]);
 362   memset(tmp.get(), 'X', sz+2);
 363
 364   // Use SafeSPrintf() to output a complex list of arguments:
 365   // - test padding and truncating %c single characters.
 366   // - test truncating %s simple strings.
 367   // - test mismatching arguments and truncating (for %d != %s).
 368   // - test zero-padding and truncating %x hexadecimal numbers.
 369   // - test outputting and truncating %d MININT.
 370   // - test outputting and truncating %p arbitrary pointer values.
 371   // - test outputting, padding and truncating NULL-pointer %s strings.
 372   char* out = tmp.get();
 373   size_t out_sz = sz;
 374   size_t len;
 375   for (scoped_ptr<char[]> perfect_buf;;) {
 376     size_t needed = SafeSNPrintf(out, out_sz,
 377 #if defined(NDEBUG)
 378                             "A%2cong %s: %d %010X %d %p%7s", 'l', "string", "",
 379 #else
 380                             "A%2cong %s: %%d %010X %d %p%7s", 'l', "string",
 381 #endif
 382                             0xDEADBEEF, std::numeric_limits<intptr_t>::min(),
 383                             PrintLongString, static_cast<char*>(NULL)) + 1;
 384
 385     // Various sanity checks:
 386     // The numbered of characters needed to print the full string should always
 387     // be bigger or equal to the bytes that have actually been output.
 388     len = strlen(tmp.get());
 389     CHECK_GE(needed, len+1);
 390
 391     // The number of characters output should always fit into the buffer that
 392     // was passed into SafeSPrintf().
 393     CHECK_LT(len, out_sz);
 394
 395     // The output is always terminated with a NUL byte (actually, this test is
 396     // always going to pass, as strlen() already verified this)
 397     EXPECT_FALSE(tmp[len]);
 398
 399     // ASAN can check that we are not overwriting buffers, iff we make sure the
 400     // buffer is exactly the size that we are expecting to be written. After
 401     // running SafeSNPrintf() the first time, it is possible to compute the
 402     // correct buffer size for this test. So, allocate a second buffer and run
 403     // the exact same SafeSNPrintf() command again.
 404     if (!perfect_buf.get()) {
 405       out_sz = std::min(needed, sz);
 406       out = new char[out_sz];
 407       perfect_buf.reset(out);
 408     } else {
 409       break;
 410     }
 411   }
 412
 413   // All trailing bytes are unchanged.
 414   for (size_t i = len+1; i < sz+2; ++i)
 415     EXPECT_EQ('X', tmp[i]);
 416
 417   // The text that was generated by SafeSPrintf() should always match the
 418   // equivalent text generated by sprintf(). Please note that the format
 419   // string for sprintf() is nor complicated, as it does not have the
 420   // benefit of getting type information from the C++ compiler.
 421   //
 422   // N.B.: It would be so much cleaner to use snprintf(). But unfortunately,
 423   //       Visual Studio doesn't support this function, and the work-arounds
 424   //       are all really awkward.
 425   char ref[256];
 426   CHECK_LE(sz, sizeof(ref));
 427   sprintf(ref, "A long string: %%d 00DEADBEEF %lld 0x%llX <NULL>",
 428           static_cast<long long>(std::numeric_limits<intptr_t>::min()),
 429           (long long)PrintLongString);
 430   ref[sz-1] = '\000';
 431
 432 #if defined(NDEBUG)
 433   const size_t kSSizeMax = std::numeric_limits<ssize_t>::max();
 434 #else
 435   const size_t kSSizeMax = internal::GetSafeSPrintfSSizeMaxForTest();
 436 #endif
 437
 438   // Compare the output from SafeSPrintf() to the one from sprintf().
 439   EXPECT_EQ(std::string(ref).substr(0, kSSizeMax-1), std::string(tmp.get()));
 440
 441   // We allocated a slightly larger buffer, so that we could perform some
 442   // extra sanity checks. Now that the tests have all passed, we copy the
 443   // data to the output buffer that the caller provided.
 444   memcpy(buf, tmp.get(), len+1);
 445 }
 446
 447 #if !defined(NDEBUG)
 448 class ScopedSafeSPrintfSSizeMaxSetter {
 449  public:
 450   ScopedSafeSPrintfSSizeMaxSetter(size_t sz) {
 451     old_ssize_max_ = internal::GetSafeSPrintfSSizeMaxForTest();
 452     internal::SetSafeSPrintfSSizeMaxForTest(sz);
 453   }
 454
 455   ~ScopedSafeSPrintfSSizeMaxSetter() {
 456     internal::SetSafeSPrintfSSizeMaxForTest(old_ssize_max_);
 457   }
 458
 459  private:
 460   size_t old_ssize_max_;
 461
 462   DISALLOW_COPY_AND_ASSIGN(ScopedSafeSPrintfSSizeMaxSetter);
 463 };
 464 #endif
 465
 466 }  // anonymous namespace
 467
 468 TEST(SafeSPrintfTest, Truncation) {
 469   // We use PrintLongString() to print a complex long string and then
 470   // truncate to all possible lengths. This ends up exercising a lot of
 471   // different code paths in SafeSPrintf() and IToASCII(), as truncation can
 472   // happen in a lot of different states.
 473   char ref[256];
 474   PrintLongString(ref, sizeof(ref));
 475   for (size_t i = strlen(ref)+1; i; --i) {
 476     char buf[sizeof(ref)];
 477     PrintLongString(buf, i);
 478     EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
 479   }
 480
 481   // When compiling in debug mode, we have the ability to fake a small
 482   // upper limit for the maximum value that can be stored in an ssize_t.
 483   // SafeSPrintf() uses this upper limit to determine how many bytes it will
 484   // write to the buffer, even if the caller claimed a bigger buffer size.
 485   // Repeat the truncation test and verify that this other code path in
 486   // SafeSPrintf() works correctly, too.
 487 #if !defined(NDEBUG)
 488   for (size_t i = strlen(ref)+1; i > 1; --i) {
 489     ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(i);
 490     char buf[sizeof(ref)];
 491     PrintLongString(buf, sizeof(buf));
 492     EXPECT_EQ(std::string(ref, i - 1), std::string(buf));
 493   }
 494
 495   // kSSizeMax is also used to constrain the maximum amount of padding, before
 496   // SafeSPrintf() detects an error in the format string.
 497   ScopedSafeSPrintfSSizeMaxSetter ssize_max_setter(100);
 498   char buf[256];
 499   EXPECT_EQ(99, SafeSPrintf(buf, "%99c", ' '));
 500   EXPECT_EQ(std::string(99, ' '), std::string(buf));
 501   *buf = '\000';
 502 #if defined(ALLOW_DEATH_TEST)
 503   EXPECT_DEATH(SafeSPrintf(buf, "%100c", ' '), "padding <= max_padding");
 504 #endif
 505   EXPECT_EQ(0, *buf);
 506 #endif
 507 }
 508
 509 TEST(SafeSPrintfTest, Padding) {
 510   char buf[40], fmt[40];
 511
 512   // Chars %c
 513   EXPECT_EQ(1, SafeSPrintf(buf, "%c", 'A'));
 514   EXPECT_EQ("A", std::string(buf));
 515   EXPECT_EQ(2, SafeSPrintf(buf, "%2c", 'A'));
 516   EXPECT_EQ(" A", std::string(buf));
 517   EXPECT_EQ(2, SafeSPrintf(buf, "%02c", 'A'));
 518   EXPECT_EQ(" A", std::string(buf));
 519   EXPECT_EQ(4, SafeSPrintf(buf, "%-2c", 'A'));
 520   EXPECT_EQ("%-2c", std::string(buf));
 521   SafeSPrintf(fmt, "%%%dc", std::numeric_limits<ssize_t>::max() - 1);
 522   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1, SafeSPrintf(buf, fmt, 'A'));
 523   SafeSPrintf(fmt, "%%%dc",
 524               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 525 #if defined(NDEBUG)
 526   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 'A'));
 527   EXPECT_EQ("%c", std::string(buf));
 528 #elif defined(ALLOW_DEATH_TEST)
 529   EXPECT_DEATH(SafeSPrintf(buf, fmt, 'A'), "padding <= max_padding");
 530 #endif
 531
 532   // Octal %o
 533   EXPECT_EQ(1, SafeSPrintf(buf, "%o", 1));
 534   EXPECT_EQ("1", std::string(buf));
 535   EXPECT_EQ(2, SafeSPrintf(buf, "%2o", 1));
 536   EXPECT_EQ(" 1", std::string(buf));
 537   EXPECT_EQ(2, SafeSPrintf(buf, "%02o", 1));
 538   EXPECT_EQ("01", std::string(buf));
 539   EXPECT_EQ(12, SafeSPrintf(buf, "%12o", -1));
 540   EXPECT_EQ(" 37777777777", std::string(buf));
 541   EXPECT_EQ(12, SafeSPrintf(buf, "%012o", -1));
 542   EXPECT_EQ("037777777777", std::string(buf));
 543   EXPECT_EQ(23, SafeSPrintf(buf, "%23o", -1LL));
 544   EXPECT_EQ(" 1777777777777777777777", std::string(buf));
 545   EXPECT_EQ(23, SafeSPrintf(buf, "%023o", -1LL));
 546   EXPECT_EQ("01777777777777777777777", std::string(buf));
 547   EXPECT_EQ(3, SafeSPrintf(buf, "%2o", 0111));
 548   EXPECT_EQ("111", std::string(buf));
 549   EXPECT_EQ(4, SafeSPrintf(buf, "%-2o", 1));
 550   EXPECT_EQ("%-2o", std::string(buf));
 551   SafeSPrintf(fmt, "%%%do", std::numeric_limits<ssize_t>::max()-1);
 552   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 553             SafeSNPrintf(buf, 4, fmt, 1));
 554   EXPECT_EQ("   ", std::string(buf));
 555   SafeSPrintf(fmt, "%%0%do", std::numeric_limits<ssize_t>::max()-1);
 556   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 557             SafeSNPrintf(buf, 4, fmt, 1));
 558   EXPECT_EQ("000", std::string(buf));
 559   SafeSPrintf(fmt, "%%%do",
 560               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 561 #if defined(NDEBUG)
 562   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
 563   EXPECT_EQ("%o", std::string(buf));
 564 #elif defined(ALLOW_DEATH_TEST)
 565   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
 566 #endif
 567
 568   // Decimals %d
 569   EXPECT_EQ(1, SafeSPrintf(buf, "%d", 1));
 570   EXPECT_EQ("1", std::string(buf));
 571   EXPECT_EQ(2, SafeSPrintf(buf, "%2d", 1));
 572   EXPECT_EQ(" 1", std::string(buf));
 573   EXPECT_EQ(2, SafeSPrintf(buf, "%02d", 1));
 574   EXPECT_EQ("01", std::string(buf));
 575   EXPECT_EQ(3, SafeSPrintf(buf, "%3d", -1));
 576   EXPECT_EQ(" -1", std::string(buf));
 577   EXPECT_EQ(3, SafeSPrintf(buf, "%03d", -1));
 578   EXPECT_EQ("-01", std::string(buf));
 579   EXPECT_EQ(3, SafeSPrintf(buf, "%2d", 111));
 580   EXPECT_EQ("111", std::string(buf));
 581   EXPECT_EQ(4, SafeSPrintf(buf, "%2d", -111));
 582   EXPECT_EQ("-111", std::string(buf));
 583   EXPECT_EQ(4, SafeSPrintf(buf, "%-2d", 1));
 584   EXPECT_EQ("%-2d", std::string(buf));
 585   SafeSPrintf(fmt, "%%%dd", std::numeric_limits<ssize_t>::max()-1);
 586   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 587             SafeSNPrintf(buf, 4, fmt, 1));
 588   EXPECT_EQ("   ", std::string(buf));
 589   SafeSPrintf(fmt, "%%0%dd", std::numeric_limits<ssize_t>::max()-1);
 590   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 591             SafeSNPrintf(buf, 4, fmt, 1));
 592   EXPECT_EQ("000", std::string(buf));
 593   SafeSPrintf(fmt, "%%%dd",
 594               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 595 #if defined(NDEBUG)
 596   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
 597   EXPECT_EQ("%d", std::string(buf));
 598 #elif defined(ALLOW_DEATH_TEST)
 599   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
 600 #endif
 601
 602   // Hex %X
 603   EXPECT_EQ(1, SafeSPrintf(buf, "%X", 1));
 604   EXPECT_EQ("1", std::string(buf));
 605   EXPECT_EQ(2, SafeSPrintf(buf, "%2X", 1));
 606   EXPECT_EQ(" 1", std::string(buf));
 607   EXPECT_EQ(2, SafeSPrintf(buf, "%02X", 1));
 608   EXPECT_EQ("01", std::string(buf));
 609   EXPECT_EQ(9, SafeSPrintf(buf, "%9X", -1));
 610   EXPECT_EQ(" FFFFFFFF", std::string(buf));
 611   EXPECT_EQ(9, SafeSPrintf(buf, "%09X", -1));
 612   EXPECT_EQ("0FFFFFFFF", std::string(buf));
 613   EXPECT_EQ(17, SafeSPrintf(buf, "%17X", -1LL));
 614   EXPECT_EQ(" FFFFFFFFFFFFFFFF", std::string(buf));
 615   EXPECT_EQ(17, SafeSPrintf(buf, "%017X", -1LL));
 616   EXPECT_EQ("0FFFFFFFFFFFFFFFF", std::string(buf));
 617   EXPECT_EQ(3, SafeSPrintf(buf, "%2X", 0x111));
 618   EXPECT_EQ("111", std::string(buf));
 619   EXPECT_EQ(4, SafeSPrintf(buf, "%-2X", 1));
 620   EXPECT_EQ("%-2X", std::string(buf));
 621   SafeSPrintf(fmt, "%%%dX", std::numeric_limits<ssize_t>::max()-1);
 622   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 623             SafeSNPrintf(buf, 4, fmt, 1));
 624   EXPECT_EQ("   ", std::string(buf));
 625   SafeSPrintf(fmt, "%%0%dX", std::numeric_limits<ssize_t>::max()-1);
 626   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 627             SafeSNPrintf(buf, 4, fmt, 1));
 628   EXPECT_EQ("000", std::string(buf));
 629   SafeSPrintf(fmt, "%%%dX",
 630               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 631 #if defined(NDEBUG)
 632   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
 633   EXPECT_EQ("%X", std::string(buf));
 634 #elif defined(ALLOW_DEATH_TEST)
 635   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
 636 #endif
 637
 638   // Pointer %p
 639   EXPECT_EQ(3, SafeSPrintf(buf, "%p", (void*)1));
 640   EXPECT_EQ("0x1", std::string(buf));
 641   EXPECT_EQ(4, SafeSPrintf(buf, "%4p", (void*)1));
 642   EXPECT_EQ(" 0x1", std::string(buf));
 643   EXPECT_EQ(4, SafeSPrintf(buf, "%04p", (void*)1));
 644   EXPECT_EQ("0x01", std::string(buf));
 645   EXPECT_EQ(5, SafeSPrintf(buf, "%4p", (void*)0x111));
 646   EXPECT_EQ("0x111", std::string(buf));
 647   EXPECT_EQ(4, SafeSPrintf(buf, "%-2p", (void*)1));
 648   EXPECT_EQ("%-2p", std::string(buf));
 649   SafeSPrintf(fmt, "%%%dp", std::numeric_limits<ssize_t>::max()-1);
 650   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 651             SafeSNPrintf(buf, 4, fmt, (void*)1));
 652   EXPECT_EQ("   ", std::string(buf));
 653   SafeSPrintf(fmt, "%%0%dp", std::numeric_limits<ssize_t>::max()-1);
 654   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 655             SafeSNPrintf(buf, 4, fmt, (void*)1));
 656   EXPECT_EQ("0x0", std::string(buf));
 657   SafeSPrintf(fmt, "%%%dp",
 658               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 659 #if defined(NDEBUG)
 660   EXPECT_EQ(2, SafeSPrintf(buf, fmt, 1));
 661   EXPECT_EQ("%p", std::string(buf));
 662 #elif defined(ALLOW_DEATH_TEST)
 663   EXPECT_DEATH(SafeSPrintf(buf, fmt, 1), "padding <= max_padding");
 664 #endif
 665
 666   // String
 667   EXPECT_EQ(1, SafeSPrintf(buf, "%s", "A"));
 668   EXPECT_EQ("A", std::string(buf));
 669   EXPECT_EQ(2, SafeSPrintf(buf, "%2s", "A"));
 670   EXPECT_EQ(" A", std::string(buf));
 671   EXPECT_EQ(2, SafeSPrintf(buf, "%02s", "A"));
 672   EXPECT_EQ(" A", std::string(buf));
 673   EXPECT_EQ(3, SafeSPrintf(buf, "%2s", "AAA"));
 674   EXPECT_EQ("AAA", std::string(buf));
 675   EXPECT_EQ(4, SafeSPrintf(buf, "%-2s", "A"));
 676   EXPECT_EQ("%-2s", std::string(buf));
 677   SafeSPrintf(fmt, "%%%ds", std::numeric_limits<ssize_t>::max()-1);
 678   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 679             SafeSNPrintf(buf, 4, fmt, "A"));
 680   EXPECT_EQ("   ", std::string(buf));
 681   SafeSPrintf(fmt, "%%0%ds", std::numeric_limits<ssize_t>::max()-1);
 682   EXPECT_EQ(std::numeric_limits<ssize_t>::max()-1,
 683             SafeSNPrintf(buf, 4, fmt, "A"));
 684   EXPECT_EQ("   ", std::string(buf));
 685   SafeSPrintf(fmt, "%%%ds",
 686               static_cast<size_t>(std::numeric_limits<ssize_t>::max()));
 687 #if defined(NDEBUG)
 688   EXPECT_EQ(2, SafeSPrintf(buf, fmt, "A"));
 689   EXPECT_EQ("%s", std::string(buf));
 690 #elif defined(ALLOW_DEATH_TEST)
 691   EXPECT_DEATH(SafeSPrintf(buf, fmt, "A"), "padding <= max_padding");
 692 #endif
 693 }
 694
 695 TEST(SafeSPrintfTest, EmbeddedNul) {
 696   char buf[] = { 'X', 'X', 'X', 'X' };
 697   EXPECT_EQ(2, SafeSPrintf(buf, "%3c", 0));
 698   EXPECT_EQ(' ', buf[0]);
 699   EXPECT_EQ(' ', buf[1]);
 700   EXPECT_EQ(0,   buf[2]);
 701   EXPECT_EQ('X', buf[3]);
 702
 703   // Check handling of a NUL format character. N.B. this takes two different
 704   // code paths depending on whether we are actually passing arguments. If
 705   // we don't have any arguments, we are running in the fast-path code, that
 706   // looks (almost) like a strncpy().
 707 #if defined(NDEBUG)
 708   EXPECT_EQ(2, SafeSPrintf(buf, "%%%"));
 709   EXPECT_EQ("%%", std::string(buf));
 710   EXPECT_EQ(2, SafeSPrintf(buf, "%%%", 0));
 711   EXPECT_EQ("%%", std::string(buf));
 712 #elif defined(ALLOW_DEATH_TEST)
 713   EXPECT_DEATH(SafeSPrintf(buf, "%%%"), "src.1. == '%'");
 714   EXPECT_DEATH(SafeSPrintf(buf, "%%%", 0), "ch");
 715 #endif
 716 }
 717
 718 TEST(SafeSPrintfTest, EmitNULL) {
 719   char buf[40];
 720 #if defined(__GNUC__)
 721 #pragma GCC diagnostic push
 722 #pragma GCC diagnostic ignored "-Wconversion-null"
 723 #endif
 724   EXPECT_EQ(1, SafeSPrintf(buf, "%d", NULL));
 725   EXPECT_EQ("0", std::string(buf));
 726   EXPECT_EQ(3, SafeSPrintf(buf, "%p", NULL));
 727   EXPECT_EQ("0x0", std::string(buf));
 728   EXPECT_EQ(6, SafeSPrintf(buf, "%s", NULL));
 729   EXPECT_EQ("<NULL>", std::string(buf));
 730 #if defined(__GCC__)
 731 #pragma GCC diagnostic pop
 732 #endif
 733 }
 734
 735 TEST(SafeSPrintfTest, PointerSize) {
 736   // The internal data representation is a 64bit value, independent of the
 737   // native word size. We want to perform sign-extension for signed integers,
 738   // but we want to avoid doing so for pointer types. This could be a
 739   // problem on systems, where pointers are only 32bit. This tests verifies
 740   // that there is no such problem.
 741   char *str = reinterpret_cast<char *>(0x80000000u);
 742   void *ptr = str;
 743   char buf[40];
 744   EXPECT_EQ(10, SafeSPrintf(buf, "%p", str));
 745   EXPECT_EQ("0x80000000", std::string(buf));
 746   EXPECT_EQ(10, SafeSPrintf(buf, "%p", ptr));
 747   EXPECT_EQ("0x80000000", std::string(buf));
 748 }
 749
 750 }  // namespace strings
 751 }  // namespace base