Make improvements

- Fix build flakes
- Polyfill SIGWINCH on Windows
- Fix an execve issue on Windows
- Make strerror show more information
- Improve cmd.exe setup/teardown on Windows
- Support bracketed paste mode in Blinkenlights
- Show keyboard shortcuts in Blinkenlights status bar
- Fixed copy_file_range() and copyfile() w/ zip filesystem
- Size optimize GetDosArgv() to keep life.com 12kb in size
- Improve Blinkenlights ability to load weird ELF executables
- Fix program_executable_name and add GetInterpreterExecutableName
- Make Python in tiny mode fail better if docstrings are requested
- Update Python test exclusions in tiny* modes such as tinylinux
- Add bulletproof unbreakable kprintf() troubleshooting function
- Remove "oldskool" keyword from ape.S for virus scanners
- Fix issue that caused backtraces to not print sometimes
- Improve Blinkenlights serial uart character i/o
- Make clock_gettime() not clobber errno on xnu
- Improve sha256 cpuid check for old computers
- Integrate some bestline linenoise fixes
- Show runit process names better in htop
- Remove SIGPIPE from ShowCrashReports()
- Make realpath() not clobber errno
- Avoid attaching GDB on non-Linux
- Improve img.com example

libc/log/backtrace2.c

@@ -27,6 +27,7 @@
 #include "libc/fmt/conv.h"
 #include "libc/fmt/fmt.h"
 #include "libc/fmt/itoa.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/log/backtrace.internal.h"
 #include "libc/log/libfatal.internal.h"
 #include "libc/log/log.h"
@@ -46,8 +47,7 @@
 #define kBacktraceMaxFrames 128
 #define kBacktraceBufSize   ((kBacktraceMaxFrames - 1) * (18 + 1))
 
-static noasan int PrintBacktraceUsingAddr2line(int fd,
-                                               const struct StackFrame *bp) {
+static int PrintBacktraceUsingAddr2line(int fd, const struct StackFrame *bp) {
   ssize_t got;
   intptr_t addr;
   size_t i, j, gi;
@@ -57,10 +57,32 @@ static noasan int PrintBacktraceUsingAddr2line(int fd,
   const struct StackFrame *frame;
   char *debugbin, *p1, *p2, *p3, *addr2line;
   char buf[kBacktraceBufSize], *argv[kBacktraceMaxFrames];
-  if (IsOpenbsd()) return -1;
-  if (IsWindows()) return -1;
-  if (!(debugbin = FindDebugBinary())) return -1;
-  if (!(addr2line = GetAddr2linePath())) return -1;
+
+  if (!(debugbin = FindDebugBinary())) {
+    if (IsLinux()) {
+      kprintf("warning: can't find debug binary try setting COMDBG%n");
+    }
+    return -1;
+  }
+
+  if (!(addr2line = GetAddr2linePath())) {
+    if (IsLinux()) {
+      kprintf("warning: can't find addr2line try setting ADDR2LINE%n");
+    }
+    return -1;
+  }
+
+  /*
+   * DWARF is a weak standard. If we build on Linux then only the
+   * precice same version of the same tools on Linux can be counted upon
+   * to work reliably. So if it's not Linux, we fall back to our builtin
+   * tooling which can be counted upon.
+   */
+  if (!IsLinux()) {
+    kprintf("note: won't print addr2line backtrace on non-linux%n");
+    return -1;
+  }
+
   i = 0;
   j = 0;
   argv[i++] = "addr2line";
@@ -92,8 +114,8 @@ static noasan int PrintBacktraceUsingAddr2line(int fd,
   if (!(pid = vfork())) {
     sigprocmask(SIG_SETMASK, &savemask, NULL);
     dup2(pipefds[1], 1);
-    close(pipefds[0]);
-    close(pipefds[1]);
+    if (pipefds[0] != 1) close(pipefds[0]);
+    if (pipefds[1] != 1) close(pipefds[1]);
     execvp(addr2line, argv);
     _exit(127);
   }
@@ -101,36 +123,6 @@ static noasan int PrintBacktraceUsingAddr2line(int fd,
   while ((got = read(pipefds[0], buf, kBacktraceBufSize)) > 0) {
     p1 = buf;
     p3 = p1 + got;
-
-    /*
-     * Remove deep libc error reporting facilities from backtraces.
-     *
-     * For example, if the following shows up in Emacs:
-     *
-     *     40d097: __die at libc/log/die.c:33
-     *     434daa: __asan_die at libc/intrin/asan.c:483
-     *     435146: __asan_report_memory_fault at libc/intrin/asan.c:524
-     *     435b32: __asan_report_store at libc/intrin/asan.c:719
-     *     43472e: __asan_report_store1 at libc/intrin/somanyasan.S:118
-     *     40c3a9: GetCipherSuite at net/https/getciphersuite.c:80
-     *     4383a5: GetCipherSuite_test at test/net/https/getciphersuite.c:23
-     *     ...
-     *
-     * Then it's unpleasant to need to press C-x C-n six times.
-     */
-#if 0
-    while ((p2 = memchr(p1, '\n', p3 - p1))) {
-      if (memmem(p1, p2 - p1, ": __asan_", 9) ||
-          memmem(p1, p2 - p1, ": __die", 7)) {
-        memmove(p1, p2 + 1, p3 - (p2 + 1));
-        p3 -= p2 + 1 - p1;
-      } else {
-        p1 = p2 + 1;
-        break;
-      }
-    }
-#endif
-
     /*
      * remove racist output from gnu tooling, that can't be disabled
      * otherwise, since it breaks other tools like emacs that aren't
@@ -165,7 +157,7 @@ static noasan int PrintBacktraceUsingAddr2line(int fd,
   }
 }
 
-static noasan int PrintBacktrace(int fd, const struct StackFrame *bp) {
+static int PrintBacktrace(int fd, const struct StackFrame *bp) {
   if (!IsTiny()) {
     if (PrintBacktraceUsingAddr2line(fd, bp) != -1) {
       return 0;
@@ -174,21 +166,23 @@ static noasan int PrintBacktrace(int fd, const struct StackFrame *bp) {
   return PrintBacktraceUsingSymbols(fd, bp, GetSymbolTable());
 }
 
-noasan void ShowBacktrace(int fd, const struct StackFrame *bp) {
+void ShowBacktrace(int fd, const struct StackFrame *bp) {
 #ifdef __FNO_OMIT_FRAME_POINTER__
   /* asan runtime depends on this function */
   static bool noreentry;
-  ++g_ftrace;
+  --g_ftrace;
   if (!bp) bp = __builtin_frame_address(0);
   if (!noreentry) {
     noreentry = true;
     PrintBacktrace(fd, bp);
     noreentry = false;
+  } else {
+    kprintf("warning: re-entered ShowBackTrace()%n");
   }
-  --g_ftrace;
+  ++g_ftrace;
 #else
-  __printf("ShowBacktrace() needs these flags to show C backtrace:\n"
-           "\t-D__FNO_OMIT_FRAME_POINTER__\n"
-           "\t-fno-omit-frame-pointer\n");
+  kprintf("ShowBacktrace() needs these flags to show C backtrace:%n"
+          "\t-D__FNO_OMIT_FRAME_POINTER__%n"
+          "\t-fno-omit-frame-pointer%n");
 #endif
 }