Make it possible to log kprintf() to file

It's now possible to compile Emacs using cosmocc. However we need to
troubleshoot why it's event loop isn't working correctly at runtime.

ape/ape.lds

@@ -304,7 +304,6 @@ SECTIONS {
     KEEP(*(.keep.text))
     *(.text .stub .text.*)
     KEEP(*(SORT_BY_NAME(.sort.text.*)))
-    *(.subrs)
 
     KEEP(*(.ape.pad.test));
     *(.test.unlikely)
@@ -402,6 +401,7 @@ SECTIONS {
 /*BEGIN: NT FORK COPYING */
     KEEP(*(.dataprologue))
     *(.data .data.*)
+    *(.subrs) /* for emacs */
     KEEP(*(SORT_BY_NAME(.sort.data.*)))
     . += . > 0 ? CODE_GRANULE : 0;
 

libc/intrin/kprintf.greg.c

@@ -103,6 +103,7 @@
       break;                                 \
   }
 
+_Hide long __klog_handle;
 extern _Hide struct SymbolTable *__symtab;
 
 privileged static inline char *kadvance(char *p, char *e, long n) {
@@ -190,18 +191,30 @@ privileged bool kisdangerous(const void *p) {
   return true;
 }
 
-privileged dontinline void klog(const char *b, size_t n) {
+privileged static long kloghandle(void) {
+  if (__klog_handle) {
+    return __klog_handle;
+  } else if (!IsWindows()) {
+    return 2;
+  } else {
+    return __imp_GetStdHandle(kNtStdErrorHandle);
+  }
+}
+
+privileged void _klog(const char *b, size_t n) {
 #ifdef __x86_64__
   int e;
+  long h;
   bool cf;
   size_t i;
   uint16_t dx;
   uint32_t wrote;
   unsigned char al;
   long rax, rdi, rsi, rdx;
+  h = kloghandle();
   if (IsWindows()) {
     e = __imp_GetLastError();
-    __imp_WriteFile(__imp_GetStdHandle(kNtStdErrorHandle), b, n, &wrote, 0);
+    __imp_WriteFile(h, b, n, &wrote, 0);
     __imp_SetLastError(e);
   } else if (IsMetal()) {
     if (_weaken(_klog_vga)) _weaken(_klog_vga)(b, n);
@@ -220,11 +233,11 @@ privileged dontinline void klog(const char *b, size_t n) {
   } else {
     asm volatile("syscall"
                  : "=a"(rax), "=D"(rdi), "=S"(rsi), "=d"(rdx)
-                 : "0"(__NR_write), "1"(2), "2"(b), "3"(n)
+                 : "0"(__NR_write), "1"(h), "2"(b), "3"(n)
                  : "rcx", "r8", "r9", "r10", "r11", "memory", "cc");
   }
 #elif defined(__aarch64__)
-  register long r0 asm("x0") = (long)2;
+  register long r0 asm("x0") = (long)h;
   register long r1 asm("x1") = (long)b;
   register long r2 asm("x2") = (long)n;
   register long r8 asm("x8") = (long)__NR_write;
@@ -840,7 +853,7 @@ privileged void kvprintf(const char *fmt, va_list v) {
   size_t n;
   char b[4000];
   n = kformat(b, sizeof(b), fmt, v);
-  klog(b, MIN(n, sizeof(b) - 1));
+  _klog(b, MIN(n, sizeof(b) - 1));
 }
 
 /**

libc/intrin/kprintf.h

@@ -8,6 +8,7 @@ size_t ksnprintf(char *, size_t, const char *, ...);
 void kvprintf(const char *, va_list);
 size_t kvsnprintf(char *, size_t, const char *, va_list);
 bool kisdangerous(const void *);
+void _klog(const char *, size_t);
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

libc/log/backtrace2.c

@@ -148,11 +148,11 @@ static int PrintBacktraceUsingAddr2line(int fd, const struct StackFrame *bp) {
                        strlen(" (discriminator ") - 1)) &&
           (p3 = memchr(p2, '\n', got - (p2 - p1)))) {
         if (p3 > p2 && p3[-1] == '\r') --p3;
-        sys_write(2, p1, p2 - p1);
+        _klog(p1, p2 - p1);
         got -= p3 - p1;
         p1 += p3 - p1;
       } else {
-        sys_write(2, p1, got);
+        _klog(p1, got);
         break;
       }
     }

libc/log/log.h

@@ -40,6 +40,7 @@ void _meminfo(int);                    /* shows malloc statistics &c. */
 void _memsummary(int);                 /* light version of same thing */
 bool IsTerminalInarticulate(void) nosideeffect;
 const char *commandvenv(const char *, const char *);
+int LogKprintfToFile(const char *);
 const char *GetAddr2linePath(void);
 const char *GetGdbPath(void);
 void ShowCrashReports(void);

libc/log/logkprintftofile.c

@@ -0,0 +1,57 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/log/log.h"
+#include "libc/sysv/consts/f.h"
+#include "libc/sysv/consts/o.h"
+
+static int __klog_fd;
+extern _Hide long __klog_handle;
+
+/**
+ * Redirects kprintf(), `--strace`, etc. output to file.
+ *
+ * @param path is filename to append to; if null is specified then
+ *     this file logging facility will be disabled; when the empty
+ *     string is specified, then the default path shall be used
+ * @return 0 on success, or -1 w/ errno
+ */
+int LogKprintfToFile(const char *path) {
+  int fd, dd;
+  if (!path) {
+    if (__klog_fd) {
+      __klog_handle = 0;
+      close(__klog_fd);
+      __klog_fd = 0;
+    }
+    return 0;
+  }
+  if (!*path) path = "/tmp/kprintf.log";
+  fd = open(path, O_WRONLY | O_APPEND | O_CREAT, 0644);
+  if (fd == -1) return -1;
+  dd = fcntl(fd, F_DUPFD_CLOEXEC, 100);
+  close(fd);
+  if (dd == -1) return -1;
+  if (__klog_fd) close(__klog_fd);
+  __klog_fd = dd;
+  __klog_handle = IsWindows() ? g_fds.p[dd].handle : dd;
+  return 0;
+}

libc/log/oncrash_amd64.c

@@ -235,11 +235,11 @@ relegated void ShowCrashReport(int err, int sig, struct siginfo *si,
     p = ShowGeneralRegisters(p, ctx);
     p = ShowSseRegisters(p, ctx);
     *p++ = '\n';
-    write(2, buf, p - buf);
+    _klog(buf, p - buf);
     ShowFunctionCalls(ctx);
   } else {
     *p++ = '\n';
-    write(2, buf, p - buf);
+    _klog(buf, p - buf);
   }
   kprintf("\n");
   if (!IsWindows()) __print_maps();

libc/runtime/finddebugbinary.c

@@ -61,7 +61,8 @@ static bool IsMyDebugBinaryImpl(const char *path) {
     // which is currently running in memory.
     if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
         (map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
-      if (GetElfSymbolValue(map, size, "_etext", &value)) {
+      if (IsElf64Binary(map, size) &&
+          GetElfSymbolValue(map, size, "_etext", &value)) {
         res = !_etext || value == (uintptr_t)_etext;
       }
       munmap(map, size);
@@ -94,7 +95,8 @@ const char *FindDebugBinary(void) {
   if (!once) {
     p = GetProgramExecutableName();
     n = strlen(p);
-    if (n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg")) {
+    if (n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg") ||
+        IsMyDebugBinary(p)) {
       res = p;
     } else if (n > 4 && READ32LE(p + n - 4) == READ32LE(".com") &&
                n + 4 < ARRAYLEN(buf)) {

libc/sock/pselect.c

@@ -17,7 +17,10 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/struct/itimerval.internal.h"
+#include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/struct/timespec.h"
+#include "libc/calls/struct/timespec.internal.h"
 #include "libc/calls/struct/timeval.h"
 #include "libc/dce.h"
 #include "libc/intrin/asan.internal.h"
@@ -25,6 +28,7 @@
 #include "libc/intrin/strace.internal.h"
 #include "libc/sock/internal.h"
 #include "libc/sock/select.h"
+#include "libc/sysv/consts/nrlinux.h"
 #include "libc/sysv/errfuns.h"
 
 /**
@@ -99,7 +103,7 @@ int pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 
   END_CANCELLATION_POINT;
   POLLTRACE("pselect(%d, %p, %p, %p, %s, %s) → %d% m", nfds, readfds, writefds,
-            exceptfds, DescribeTimeval(0, timeout), DescribeSigset(0, sigmask),
+            exceptfds, DescribeTimespec(0, timeout), DescribeSigset(0, sigmask),
             rc);
   return rc;
 }

libc/sock/select.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/sock/select.h"
 #include "libc/calls/cp.internal.h"
+#include "libc/calls/struct/itimerval.internal.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/calls/struct/timeval.h"
 #include "libc/dce.h"

tool/scripts/cosmoc++

@@ -30,7 +30,7 @@ exit 0
 fi
 
 CXX="/opt/cosmo/o/third_party/gcc/bin/x86_64-linux-musl-g++"
-CCFLAGS="-g -O2 -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
+CCFLAGS="-g -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
 CXXFLAGS="-fno-exceptions -fuse-cxa-atexit -fno-threadsafe-statics"
 CPPFLAGS="-DNDEBUG -nostdinc -iquote /opt/cosmo -isystem /opt/cosmos/include -isystem /opt/cosmo/libc/isystem -include libc/integral/normalize.inc"
 LDFLAGS="-static -no-pie -nostdlib -fuse-ld=bfd -Wl,-melf_x86_64 -Wl,--gc-sections -L/opt/cosmos/lib -Wl,-T,/opt/cosmo/o/ape/public/ape.lds /opt/cosmo/o/ape/ape-no-modify-self.o /opt/cosmo/o/libc/crt/crt.o"

tool/scripts/cosmocc

@@ -33,7 +33,7 @@ exit 0
 fi
 
 CC="/opt/cosmo/o/third_party/gcc/bin/x86_64-linux-musl-gcc"
-CFLAGS="-g -O2 -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
+CFLAGS="-g -fdata-sections -ffunction-sections -fno-pie -pg -mnop-mcount -mno-tls-direct-seg-refs -fportcosmo -include /opt/cosmo/build/portcosmo.h"
 CPPFLAGS="-DNDEBUG -nostdinc -iquote /opt/cosmo -isystem $COSMOS/include -isystem /opt/cosmo/libc/isystem -include libc/integral/normalize.inc"
 LDFLAGS="-static -no-pie -nostdlib -fuse-ld=bfd -Wl,-melf_x86_64 -Wl,--gc-sections -Wl,-z,max-page-size=0x1000 -L$COSMOS/lib -Wl,-T,/opt/cosmo/o/ape/public/ape.lds /opt/cosmo/o/ape/ape-no-modify-self.o /opt/cosmo/o/libc/crt/crt.o"
 LDLIBS="/opt/cosmo/o/cosmopolitan.a"