Make improvements

- Invent openatemp() API
- Invent O_UNLINK open flag
- Introduce getenv_secure() API
- Remove `git pull` from cosmocc
- Fix utimes() when path is NULL
- Fix mktemp() to never return NULL
- Fix utimensat() UTIME_OMIT on XNU
- Improve utimensat() code for RHEL5
- Turn `argv[0]` C:/ to /C/ on Windows
- Introduce tmpnam() and tmpnam_r() APIs
- Fix more const issues with internal APIs
- Permit utimes() on WIN32 in O_RDONLY mode
- Fix fdopendir() to check fd is a directory
- Fix recent crash regression in landlock make
- Fix futimens(AT_FDCWD, NULL) to return EBADF
- Use workaround so `make -j` doesn't fork bomb
- Rename dontdiscard to __wur (just like glibc)
- Fix st_size for WIN32 symlinks containing UTF-8
- Introduce stdio ext APIs needed by GNU coreutils
- Fix lstat() on WIN32 for symlinks to directories
- Move some constants from normalize.inc to limits.h
- Fix segv with memchr() and memcmp() overlapping page
- Implement POSIX fflush() behavior for reader streams
- Implement AT_SYMLINK_NOFOLLOW for utimensat() on WIN32
- Don't change read-only status of existing files on WIN32
- Correctly handle `0x[^[:xdigit:]]` case in strtol() functions

libc/calls/utimensat-old.c

@@ -0,0 +1,117 @@
+/*-*- 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 2020 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/assert.h"
+#include "libc/calls/calls.h"
+#include "libc/calls/struct/stat.h"
+#include "libc/calls/struct/stat.internal.h"
+#include "libc/calls/struct/timespec.internal.h"
+#include "libc/calls/struct/timeval.h"
+#include "libc/calls/struct/timeval.internal.h"
+#include "libc/dce.h"
+#include "libc/fmt/itoa.h"
+#include "libc/limits.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/at.h"
+#include "libc/sysv/consts/utime.h"
+#include "libc/sysv/errfuns.h"
+
+int sys_utimensat_old(int dirfd, const char *path, const struct timespec ts[2],
+                      int flags) {
+  char buf[PATH_MAX + 1];
+
+  // validate usage
+  if (path) {
+    if (dirfd != AT_FDCWD) {
+      return enotsup();
+    }
+  } else {
+    unassert(dirfd >= 0);
+  }
+  if (flags) {
+    return einval();
+  }
+
+  // xnu has futimes(), but rhel5 only has utimes()
+  // on linux we'll try to get the path from procfs
+  if (IsLinux() && !path) {
+    char procpath[36];
+    char *p = procpath;
+    p = stpcpy(p, "/proc/");
+    p = FormatInt32(p, getpid());
+    p = stpcpy(p, "/fd/");
+    p = FormatInt32(p, dirfd);
+    ssize_t got;
+    if ((got = readlink(procpath, buf, sizeof(buf))) == -1) {
+      return -1;
+    }
+    if (got == sizeof(buf)) {
+      return enametoolong();
+    }
+    unassert(buf[0] == '/');
+    buf[got] = 0;
+    path = buf;
+  }
+
+  // perform preliminary system calls ahead of time
+  struct timeval now;
+  if (!ts || ts[0].tv_nsec == UTIME_NOW || ts[1].tv_nsec == UTIME_NOW) {
+    unassert(!gettimeofday(&now, 0));
+  }
+  struct stat st;
+  if (ts && (ts[0].tv_nsec == UTIME_OMIT || ts[1].tv_nsec == UTIME_OMIT)) {
+    if (path) {
+      if (sys_fstatat(AT_FDCWD, path, &st, 0) == -1) {
+        return -1;
+      }
+    } else {
+      if (sys_fstat(dirfd, &st) == -1) {
+        return -1;
+      }
+    }
+  }
+
+  // change the timestamps
+  struct timeval tv[2];
+  if (ts) {
+    if (ts[0].tv_nsec == UTIME_NOW) {
+      tv[0] = now;
+    } else if (ts[0].tv_nsec == UTIME_OMIT) {
+      tv[0] = timespec_totimeval(st.st_atim);
+    } else {
+      tv[0] = timespec_totimeval(ts[0]);
+    }
+    if (ts[1].tv_nsec == UTIME_NOW) {
+      tv[1] = now;
+    } else if (ts[1].tv_nsec == UTIME_OMIT) {
+      tv[1] = timespec_totimeval(st.st_mtim);
+    } else {
+      tv[1] = timespec_totimeval(ts[1]);
+    }
+  } else {
+    tv[0] = now;
+    tv[1] = now;
+  }
+
+  // apply the new timestamps
+  if (path) {
+    return sys_utimes(path, tv);
+  } else {
+    return sys_futimes(dirfd, tv);
+  }
+}