Fix a bunch of Windows bugs reported on Discord

This change addresses everything from stack smashing to %SYSTEMROOT%
breaking socket(). Issues relating to compile.com not reporting text
printed to stderr has been resolved for Windows builds.

libc/calls/mkntenvblock.c

@@ -18,11 +18,13 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/ntspawn.h"
 #include "libc/fmt/conv.h"
+#include "libc/intrin/_getenv.internal.h"
 #include "libc/intrin/bits.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/alloca.h"
 #include "libc/mem/arraylist2.internal.h"
 #include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
 #include "libc/str/str.h"
 #include "libc/str/thompike.h"
 #include "libc/str/utf16.h"
@@ -91,12 +93,15 @@ static textwindows void FixPath(char *path) {
 }
 
 static textwindows void InsertString(char **a, size_t i, char *s,
-                                     char buf[ARG_MAX], size_t *bufi) {
+                                     char buf[ARG_MAX], size_t *bufi,
+                                     bool *have_systemroot) {
   char *v;
   size_t j, k;
 
+  v = StrChr(s, '=');
+
   // apply fixups to var=/c/...
-  if ((v = StrChr(s, '=')) && v[1] == '/' && IsAlpha(v[2]) && v[3] == '/') {
+  if (v && v[1] == '/' && IsAlpha(v[2]) && v[3] == '/') {
     v = buf + *bufi;
     for (k = 0; s[k]; ++k) {
       if (*bufi + 1 < ARG_MAX) {
@@ -136,11 +141,25 @@ textwindows int mkntenvblock(char16_t envvars[ARG_MAX / 2], char *const envp[],
   uint64_t w;
   char **vars;
   wint_t x, y;
+  bool have_systemroot = false;
   size_t i, j, k, n, m, bufi = 0;
   for (n = 0; envp[n];) n++;
   vars = alloca((n + 1) * sizeof(char *));
-  for (i = 0; i < n; ++i) InsertString(vars, i, envp[i], buf, &bufi);
-  if (extravar) InsertString(vars, n++, extravar, buf, &bufi);
+  for (i = 0; i < n; ++i) {
+    InsertString(vars, i, envp[i], buf, &bufi, &have_systemroot);
+  }
+  if (extravar) {
+    InsertString(vars, n++, extravar, buf, &bufi, &have_systemroot);
+  }
+  if (!have_systemroot && environ) {
+    // https://jpassing.com/2009/12/28/the-hidden-danger-of-forgetting-to-specify-systemroot-in-a-custom-environment-block/
+    struct Env systemroot;
+    systemroot = _getenv(environ, "SYSTEMROOT");
+    if (systemroot.s) {
+      InsertString(vars, n++, environ[systemroot.i], buf, &bufi,
+                   &have_systemroot);
+    }
+  }
   for (k = i = 0; i < n; ++i) {
     j = 0;
     v = false;

libc/elf/getelfsectionaddress.c

@@ -31,17 +31,15 @@
  * @param shdr is from GetElfSectionHeaderAddress(), or null
  * @return pointer to section data within image, or null if
  *     1. `shdr` was null, or
- *     2. `sh_size` was zero, or
- *     3, `sh_type` was `SHT_NOBITS`, or
- *     4. content wasn't contained within `[elf,elf+mapsize)`, or
- *     5. an arithmetic overflow occurred
+ *     2. content wasn't contained within `[elf,elf+mapsize)`, or
+ *     3. an arithmetic overflow occurred
  */
 void *GetElfSectionAddress(const Elf64_Ehdr *elf,     // validated
                            size_t mapsize,            // validated
                            const Elf64_Shdr *shdr) {  // foreign
   Elf64_Off last;
   if (!shdr) return 0;
-  if (shdr->sh_size <= 0) return 0;
+  if (!shdr->sh_size) return elf;
   if (shdr->sh_type == SHT_NOBITS) return 0;
   if (ckd_add(&last, shdr->sh_offset, shdr->sh_size)) return 0;
   if (last > mapsize) return 0;

libc/intrin/describentpipeopenflags.c

@@ -18,16 +18,24 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/macros.internal.h"
+#include "libc/nt/enum/accessmask.h"
+#include "libc/nt/enum/fileflagandattributes.h"
 #include "libc/nt/enum/filemapflags.h"
 #include "libc/nt/ipc.h"
 
 static const struct DescribeFlags kPipeOpenFlags[] = {
-    {kNtPipeAccessDuplex, "Duplex"},      // 0x00000003
-    {kNtPipeAccessOutbound, "Outbound"},  // 0x00000002
-    {kNtPipeAccessInbound, "Inbound"},    // 0x00000001
+    {kNtPipeAccessDuplex, "kNtPipeAccessDuplex"},
+    {kNtPipeAccessOutbound, "kNtPipeAccessOutbound"},
+    {kNtPipeAccessInbound, "kNtPipeAccessInbound"},
+    {kNtFileFlagOverlapped, "kNtFileFlagOverlapped"},
+    {kNtFileFlagFirstPipeInstance, "kNtFileFlagFirstPipeInstance"},
+    {kNtFileFlagWriteThrough, "kNtFileFlagWriteThrough"},
+    {kNtWriteDac, "kNtWriteDac"},
+    {kNtWriteOwner, "kNtWriteOwner"},
+    {kNtAccessSystemSecurity, "kNtAccessSystemSecurity"},
 };
 
 const char *(DescribeNtPipeOpenFlags)(char buf[64], uint32_t x) {
-  return DescribeFlags(buf, 64, kPipeOpenFlags, ARRAYLEN(kPipeOpenFlags),
-                       "kNtPipeAccess", x);
+  return DescribeFlags(buf, 64, kPipeOpenFlags, ARRAYLEN(kPipeOpenFlags), "",
+                       x);
 }

libc/intrin/describentsecurityattributes.c

@@ -17,10 +17,13 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/state.internal.h"
+#include "libc/fmt/itoa.h"
 #include "libc/intrin/describeflags.internal.h"
 #include "libc/nt/struct/securityattributes.h"
 
-const char *DescribeNtSecurityAttributes(struct NtSecurityAttributes *p) {
+const char *(DescribeNtSecurityAttributes)(char buf[32],
+                                           struct NtSecurityAttributes *p) {
   if (p == &kNtIsInheritable) return "&kNtIsInheritable";
-  return "0";
+  FormatInt64(buf, (uintptr_t)p);
+  return buf;
 }

libc/nt/struct/securityattributes.h

@@ -1,5 +1,6 @@
 #ifndef COSMOPOLITAN_LIBC_NT_STRUCT_SECURITYATTRIBUTES_H_
 #define COSMOPOLITAN_LIBC_NT_STRUCT_SECURITYATTRIBUTES_H_
+#include "libc/mem/alloca.h"
 #include "libc/nt/struct/securitydescriptor.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 
@@ -9,7 +10,10 @@ struct NtSecurityAttributes {
   bool32 bInheritHandle;
 };
 
-const char *DescribeNtSecurityAttributes(struct NtSecurityAttributes *);
+const char *DescribeNtSecurityAttributes(char[32],
+                                         struct NtSecurityAttributes *);
+#define DescribeNtSecurityAttributes(x) \
+  DescribeNtSecurityAttributes(alloca(32), x)
 
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_NT_STRUCT_SECURITYATTRIBUTES_H_ */