Make more fixes and improvements

- Remove PAGESIZE constant
- Fix realloc() documentation
- Fix ttyname_r() error reporting
- Make forking more reliable on Windows
- Make execvp() a few microseconds faster
- Make system() a few microseconds faster
- Tighten up the socket-related magic numbers
- Loosen restrictions on mmap() offset alignment
- Improve GetProgramExecutableName() with getenv("_")
- Use mkstemp() as basis for mktemp(), tmpfile(), tmpfd()
- Fix flakes in pthread_cancel_test, unix_test, fork_test
- Fix recently introduced futex stack overflow regression
- Let sockets be passed as stdio to subprocesses on Windows
- Improve security of bind() on Windows w/ SO_EXCLUSIVEADDRUSE

test/libc/runtime/fork_test.c

@@ -16,15 +16,19 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/atomic.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/sigset.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/dce.h"
+#include "libc/errno.h"
 #include "libc/intrin/kprintf.h"
 #include "libc/log/check.h"
 #include "libc/macros.internal.h"
 #include "libc/nexgen32e/rdtsc.h"
 #include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/msync.h"
 #include "libc/sysv/consts/prot.h"
@@ -38,6 +42,7 @@ TEST(fork, testPipes) {
   int a, b;
   int ws, pid;
   int pipefds[2];
+  alarm(5);
   ASSERT_NE(-1, pipe(pipefds));
   ASSERT_NE(-1, (pid = fork()));
   if (!pid) {
@@ -52,9 +57,11 @@ TEST(fork, testPipes) {
   EXPECT_NE(-1, close(pipefds[0]));
   EXPECT_NE(-1, waitpid(pid, &ws, 0));
   EXPECT_EQ(31337, b);
+  alarm(0);
 }
 
 TEST(fork, testSharedMemory) {
+  alarm(5);
   int ws, pid;
   int stackvar;
   int *sharedvar;
@@ -86,6 +93,7 @@ TEST(fork, testSharedMemory) {
   EXPECT_EQ(1, *privatevar);
   EXPECT_NE(-1, munmap(sharedvar, FRAMESIZE));
   EXPECT_NE(-1, munmap(privatevar, FRAMESIZE));
+  alarm(0);
 }
 
 static volatile bool gotsigusr1;
@@ -109,6 +117,7 @@ TEST(fork, childToChild) {
   signal(SIGUSR1, OnSigusr1);
   signal(SIGUSR2, OnSigusr2);
   sigemptyset(&mask);
+  sigaddset(&mask, SIGUSR1);
   sigaddset(&mask, SIGUSR2);
   sigprocmask(SIG_BLOCK, &mask, &oldmask);
   ASSERT_NE(-1, (child1 = fork()));
@@ -117,28 +126,27 @@ TEST(fork, childToChild) {
     sigsuspend(0);
     _Exit(!gotsigusr1);
   }
-  sigdelset(&mask, SIGUSR2);
-  sigsuspend(&mask);
+  sigsuspend(0);
   ASSERT_NE(-1, (child2 = fork()));
   if (!child2) {
     kill(child1, SIGUSR1);
     _Exit(0);
   }
   ASSERT_NE(-1, wait(&ws));
-  EXPECT_TRUE(WIFEXITED(ws));
-  EXPECT_EQ(0, WEXITSTATUS(ws));
+  EXPECT_EQ(0, ws);
   ASSERT_NE(-1, wait(&ws));
-  EXPECT_TRUE(WIFEXITED(ws));
-  EXPECT_EQ(0, WEXITSTATUS(ws));
+  EXPECT_EQ(0, ws);
   sigprocmask(SIG_SETMASK, &oldmask, 0);
 }
 
 TEST(fork, preservesTlsMemory) {
+  alarm(5);
   int pid;
   __get_tls()->tib_errno = 31337;
   SPAWN(fork);
   ASSERT_EQ(31337, __get_tls()->tib_errno);
   EXITS(0);
+  alarm(0);
 }
 
 void ForkInSerial(void) {

test/libc/runtime/mmap_test.c

@@ -22,6 +22,7 @@
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/fmt/fmt.h"
+#include "libc/intrin/asan.internal.h"
 #include "libc/intrin/atomic.h"
 #include "libc/intrin/bits.h"
 #include "libc/intrin/kprintf.h"
@@ -37,6 +38,7 @@
 #include "libc/stdio/rand.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
+#include "libc/sysv/consts/auxv.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/msync.h"
 #include "libc/sysv/consts/o.h"
@@ -94,7 +96,8 @@ TEST(mmap, noreplaceExistingMap) {
 
 TEST(mmap, smallerThanPage_mapsRemainder) {
   long pagesz = sysconf(_SC_PAGESIZE);
-  char *map = mmap(0, 1, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  char *map =
+      mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   ASSERT_NE(MAP_FAILED, map);
   EXPECT_TRUE(testlib_memoryexists(map));
   EXPECT_TRUE(testlib_memoryexists(map + (pagesz - 1)));
@@ -103,6 +106,16 @@ TEST(mmap, smallerThanPage_mapsRemainder) {
   EXPECT_FALSE(testlib_memoryexists(map + (pagesz - 1)));
 }
 
+TEST(mmap, smallerThanPage_remainderIsPoisoned) {
+  if (!IsAsan()) return;
+  char *map;
+  ASSERT_NE(MAP_FAILED, (map = mmap(0, 1, PROT_READ | PROT_WRITE,
+                                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)));
+  EXPECT_TRUE(__asan_is_valid(map, 1));
+  EXPECT_FALSE(__asan_is_valid(map + 1, 1));
+  EXPECT_SYS(0, 0, munmap(map, 1));
+}
+
 TEST(mmap, testMapFile) {
   int fd;
   char *p;
@@ -130,7 +143,7 @@ TEST(mmap, testMapFile_fdGetsClosed_makesNoDifference) {
   EXPECT_NE(-1, close(fd));
   EXPECT_STREQN("hello", p, 5);
   p[1] = 'a';
-  EXPECT_NE(-1, msync(p, PAGESIZE, MS_SYNC));
+  EXPECT_NE(-1, msync(p, getauxval(AT_PAGESZ), MS_SYNC));
   ASSERT_NE(-1, (fd = open(path, O_RDONLY)));
   EXPECT_EQ(5, read(fd, buf, 5));
   EXPECT_STREQN("hallo", buf, 5);
@@ -179,15 +192,16 @@ TEST(mmap, customStackMemory_isAuthorized) {
 TEST(mmap, fileOffset) {
   int fd;
   char *map;
+  int offset_align = IsWindows() ? FRAMESIZE : getauxval(AT_PAGESZ);
   ASSERT_NE(-1, (fd = open("foo", O_CREAT | O_RDWR, 0644)));
-  EXPECT_NE(-1, ftruncate(fd, FRAMESIZE * 2));
-  EXPECT_NE(-1, pwrite(fd, "hello", 5, FRAMESIZE * 0));
-  EXPECT_NE(-1, pwrite(fd, "there", 5, FRAMESIZE * 1));
+  EXPECT_NE(-1, ftruncate(fd, offset_align * 2));
+  EXPECT_NE(-1, pwrite(fd, "hello", 5, offset_align * 0));
+  EXPECT_NE(-1, pwrite(fd, "there", 5, offset_align * 1));
   EXPECT_NE(-1, fdatasync(fd));
-  ASSERT_NE(MAP_FAILED, (map = mmap(NULL, FRAMESIZE, PROT_READ, MAP_PRIVATE, fd,
-                                    FRAMESIZE)));
+  ASSERT_NE(MAP_FAILED, (map = mmap(NULL, offset_align, PROT_READ, MAP_PRIVATE,
+                                    fd, offset_align)));
   EXPECT_EQ(0, memcmp(map, "there", 5), "%#.*s", 5, map);
-  EXPECT_NE(-1, munmap(map, FRAMESIZE));
+  EXPECT_NE(-1, munmap(map, offset_align));
   EXPECT_NE(-1, close(fd));
 }