[Msan] Fix tests reading /proc files on FreeBSD

[samsonov]

LGTM

compiler-rt/trunk/lib/msan/tests/msan_test.cc

 #else
 # define MSAN_HAS_M128 0
 #endif
 
 #ifdef __AVX2__
 # include <immintrin.h>
 #endif
 
+// On FreeBSD procfs is not enabled by default.
+#if defined(__FreeBSD__)
+# define FILE_TO_READ "/bin/cat"
+#else
+# define FILE_TO_READ "/proc/self/stat"
+#endif
+
 static const size_t kPageSize = 4096;
 
 typedef unsigned char      U1;
 typedef unsigned short     U2;  // NOLINT
 typedef unsigned int       U4;
 typedef unsigned long long U8;  // NOLINT
 typedef   signed char      S1;
 typedef   signed short     S2;  // NOLINT
TEST(MemorySanitizer, strerror_r) {
   char *res = strerror_r(EINVAL, buf, sizeof(buf));
   ASSERT_EQ(0, errno);
   if (!res) res = buf; // POSIX version success.
   EXPECT_NOT_POISONED(strlen(res));
 }
 
 TEST(MemorySanitizer, fread) {
   char *x = new char[32];
-  FILE *f = fopen("/proc/self/stat", "r");
+  FILE *f = fopen(FILE_TO_READ, "r");
   ASSERT_TRUE(f != NULL);
   fread(x, 1, 32, f);
   EXPECT_NOT_POISONED(x[0]);
   EXPECT_NOT_POISONED(x[16]);
   EXPECT_NOT_POISONED(x[31]);
   fclose(f);
   delete[] x;
 }
 
 TEST(MemorySanitizer, read) {
   char *x = new char[32];
-  int fd = open("/proc/self/stat", O_RDONLY);
+  int fd = open(FILE_TO_READ, O_RDONLY);
   ASSERT_GT(fd, 0);
   int sz = read(fd, x, 32);
   ASSERT_EQ(sz, 32);
   EXPECT_NOT_POISONED(x[0]);
   EXPECT_NOT_POISONED(x[16]);
   EXPECT_NOT_POISONED(x[31]);
   close(fd);
   delete[] x;
 }
 
 TEST(MemorySanitizer, pread) {
   char *x = new char[32];
-  int fd = open("/proc/self/stat", O_RDONLY);
+  int fd = open(FILE_TO_READ, O_RDONLY);
   ASSERT_GT(fd, 0);
   int sz = pread(fd, x, 32, 0);
   ASSERT_EQ(sz, 32);
   EXPECT_NOT_POISONED(x[0]);
   EXPECT_NOT_POISONED(x[16]);
   EXPECT_NOT_POISONED(x[31]);
   close(fd);
   delete[] x;
 }
 
 TEST(MemorySanitizer, readv) {
   char buf[2011];
   struct iovec iov[2];
   iov[0].iov_base = buf + 1;
   iov[0].iov_len = 5;
   iov[1].iov_base = buf + 10;
   iov[1].iov_len = 2000;
-  int fd = open("/proc/self/stat", O_RDONLY);
+  int fd = open(FILE_TO_READ, O_RDONLY);
   ASSERT_GT(fd, 0);
   int sz = readv(fd, iov, 2);
   ASSERT_GE(sz, 0);
   ASSERT_LT(sz, 5 + 2000);
   ASSERT_GT((size_t)sz, iov[0].iov_len);
   EXPECT_POISONED(buf[0]);
   EXPECT_NOT_POISONED(buf[1]);
   EXPECT_NOT_POISONED(buf[5]);
   EXPECT_POISONED(buf[6]);
   EXPECT_POISONED(buf[9]);
   EXPECT_NOT_POISONED(buf[10]);
   EXPECT_NOT_POISONED(buf[10 + (sz - 1) - 5]);
   EXPECT_POISONED(buf[11 + (sz - 1) - 5]);
   close(fd);
 }
 
 TEST(MemorySanitizer, preadv) {
   char buf[2011];
   struct iovec iov[2];
   iov[0].iov_base = buf + 1;
   iov[0].iov_len = 5;
   iov[1].iov_base = buf + 10;
   iov[1].iov_len = 2000;
-  int fd = open("/proc/self/stat", O_RDONLY);
+  int fd = open(FILE_TO_READ, O_RDONLY);
   ASSERT_GT(fd, 0);
   int sz = preadv(fd, iov, 2, 3);
   ASSERT_GE(sz, 0);
   ASSERT_LT(sz, 5 + 2000);
   ASSERT_GT((size_t)sz, iov[0].iov_len);
   EXPECT_POISONED(buf[0]);
   EXPECT_NOT_POISONED(buf[1]);
   EXPECT_NOT_POISONED(buf[5]);

 
 TEST(MemorySanitizer, readlink) {
   char *x = new char[1000];
   readlink("/proc/self/exe", x, 1000);
   EXPECT_NOT_POISONED(x[0]);
   delete [] x;
 }
 
-
 TEST(MemorySanitizer, stat) {
   struct stat* st = new struct stat;
-  int res = stat("/proc/self/stat", st);
+  int res = stat(FILE_TO_READ, st);
   ASSERT_EQ(0, res);
   EXPECT_NOT_POISONED(st->st_dev);
   EXPECT_NOT_POISONED(st->st_mode);
   EXPECT_NOT_POISONED(st->st_size);
 }
 
 TEST(MemorySanitizer, fstatat) {
   struct stat* st = new struct stat;