Add more missing libc/libc++ functions

- Add sched_rr_get_interval()
- Add `unbuffer` command example
- Add more locale function stubs
- Vendor most of remaining libcxx content

examples/unbuffer.c

@@ -0,0 +1,143 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include "libc/calls/calls.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/termios.h"
+#include "libc/calls/struct/winsize.h"
+#include "libc/calls/termios.h"
+#include "libc/calls/ttydefaults.h"
+#include "libc/log/check.h"
+#include "libc/log/log.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/consts/termios.h"
+#include "libc/sysv/consts/w.h"
+
+#define STR(s) s, strlen(s)
+
+struct termios tio;
+struct winsize wsz;
+sigset_t chldmask, savemask;
+struct sigaction ignore, saveint, savequit;
+char databuf[512];
+char pathbuf[PATH_MAX];
+
+int main(int argc, char *argv[]) {
+  ssize_t rc;
+  const char *prog;
+  size_t i, got, wrote;
+  int ws, mfd, sfd, pid;
+
+  if (argc < 2) {
+    write(2, STR("usage: "));
+    if (argc > 0) write(2, argv[0], strlen(argv[0]));
+    write(2, STR(" prog [argv₁...]\n"));
+    return 1;
+  }
+
+  if (!(prog = commandv(argv[1], pathbuf, sizeof(pathbuf)))) {
+    write(2, STR("error: "));
+    write(2, prog, strlen(prog));
+    write(2, STR(" not found\n"));
+    return 2;
+  }
+
+  bzero(&wsz, sizeof(wsz));
+  wsz.ws_col = 80;
+  wsz.ws_row = 45;
+
+  bzero(&tio, sizeof(tio));
+  tio.c_iflag = ICRNL | IXON | IUTF8;
+  tio.c_oflag = OPOST | ONLCR;
+  tio.c_cflag = CREAD | CS8;
+  tio.c_lflag =
+      ISIG | ICANON | ECHO | ECHOE | ECHOK | IEXTEN | ECHOCTL | ECHOKE;
+  tio.c_cc[VMIN] = 1;
+  tio.c_cc[VINTR] = CTRL('C');
+  tio.c_cc[VQUIT] = CTRL('\\');
+  tio.c_cc[VERASE] = CTRL('?');
+  tio.c_cc[VKILL] = CTRL('U');
+  tio.c_cc[VEOF] = CTRL('D');
+  tio.c_cc[VSTART] = CTRL('Q');
+  tio.c_cc[VSTOP] = CTRL('S');
+  tio.c_cc[VSUSP] = CTRL('Z');
+  tio.c_cc[VREPRINT] = CTRL('R');
+  tio.c_cc[VDISCARD] = CTRL('O');
+  tio.c_cc[VWERASE] = CTRL('W');
+  tio.c_cc[VLNEXT] = CTRL('V');
+
+  if (openpty(&mfd, &sfd, 0, &tio, &wsz)) {
+    write(2, STR("error: openpty() failed\n"));
+    return 3;
+  }
+
+  ignore.sa_flags = 0;
+  ignore.sa_handler = SIG_IGN;
+  sigemptyset(&ignore.sa_mask);
+  sigaction(SIGINT, &ignore, &saveint);
+  sigaction(SIGQUIT, &ignore, &savequit);
+  sigemptyset(&chldmask);
+  sigaddset(&chldmask, SIGCHLD);
+  sigprocmask(SIG_BLOCK, &chldmask, &savemask);
+
+  if ((pid = vfork()) == -1) {
+    write(2, STR("error: vfork() failed\n"));
+    return 4;
+  }
+
+  if (!pid) {
+    close(0);
+    dup(sfd);
+    close(1);
+    dup(sfd);
+    close(2);
+    dup(sfd);
+    close(mfd);
+    sigaction(SIGINT, &saveint, 0);
+    sigaction(SIGQUIT, &savequit, 0);
+    sigprocmask(SIG_SETMASK, &savemask, 0);
+    execv(prog, argv + 1);
+    return 127;
+  }
+  close(sfd);
+
+  for (;;) {
+    if (waitpid(pid, &ws, WNOHANG) == pid) {
+      break;
+    }
+    rc = read(mfd, databuf, sizeof(databuf));
+    if (rc == -1) {
+      perror("read");
+      return 5;
+    }
+    if (!(got = rc)) {
+      continue;
+    }
+    for (i = 0; i < got; i += wrote) {
+      rc = write(1, databuf + i, got - i);
+      if (rc != -1) {
+        wrote = rc;
+      } else {
+        write(2, STR("error: read() failed\n"));
+        return 5;
+      }
+    }
+  }
+
+  sigaction(SIGINT, &saveint, 0);
+  sigaction(SIGQUIT, &savequit, 0);
+  sigprocmask(SIG_SETMASK, &savemask, 0);
+
+  if (WIFEXITED(ws)) {
+    return WEXITSTATUS(ws);
+  } else {
+    return 128 + WTERMSIG(ws);
+  }
+}