Strongly link glob() into system() and popen()

libc/system/system.c

@@ -0,0 +1,99 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et 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/calls/blockcancel.internal.h"
+#include "libc/calls/calls.h"
+#include "libc/calls/struct/rusage.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/intrin/weaken.h"
+#include "libc/log/log.h"
+#include "libc/paths.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/ok.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/thread/thread.h"
+
+/**
+ * Launches program with system command interpreter.
+ *
+ * This implementation embeds the Cosmopolitan Command Interpreter which
+ * provides Bourne-like syntax on all platforms, including Windows. Many
+ * builtin commands are included, e.g. exit, cd, rm, [, cat, wait, exec,
+ * env, echo, read, true, test, kill, touch, rmdir, mkdir, false, mktemp
+ * and usleep. It's also possible to __static_yoink() the symbols `_tr`,
+ * `_sed`, `_awk`, and `_curl` for the tr, sed, awk and curl commands if
+ * you're using the Cosmopolitan mono-repo.
+ *
+ * If you just have a program name and arguments, and you don't need the
+ * full power of a UNIX-like shell, then consider using the Cosmopolitan
+ * provided API systemvpe() instead. It provides a safer alternative for
+ * variable arguments than shell script escaping. It lets you clean your
+ * environment variables, for even more safety. Finally it's 10x faster.
+ *
+ * It's important to check the returned status code. For example, if you
+ * press CTRL-C while running your program you'll expect it to terminate
+ * however that won't be the case if the SIGINT gets raised while inside
+ * the system() function. If the child process doesn't handle the signal
+ * then this will return e.g. WIFSIGNALED(ws) && WTERMSIG(ws) == SIGINT.
+ *
+ * @param cmdline is a unix shell script
+ * @return -1 if child process couldn't be created, otherwise a wait
+ *     status that can be accessed using macros like WEXITSTATUS(s),
+ *     WIFSIGNALED(s), WTERMSIG(s), etc.
+ * @see systemve()
+ * @threadsafe
+ */
+int system(const char *cmdline) {
+  int pid, wstatus;
+  sigset_t chldmask, savemask;
+  if (!cmdline)
+    return 1;
+  sigemptyset(&chldmask);
+  sigaddset(&chldmask, SIGINT);
+  sigaddset(&chldmask, SIGQUIT);
+  sigaddset(&chldmask, SIGCHLD);
+  sigprocmask(SIG_BLOCK, &chldmask, &savemask);
+  if (!(pid = fork())) {
+    sigprocmask(SIG_SETMASK, &savemask, 0);
+    _Exit(_cocmd(3, (char *[]){"system", "-c", (char *)cmdline, 0}, environ));
+  } else if (pid == -1) {
+    wstatus = -1;
+  } else {
+    struct sigaction ignore, saveint, savequit;
+    ignore.sa_flags = 0;
+    ignore.sa_handler = SIG_IGN;
+    sigemptyset(&ignore.sa_mask);
+    sigaction(SIGINT, &ignore, &saveint);
+    sigaction(SIGQUIT, &ignore, &savequit);
+    BLOCK_CANCELATION;
+    while (wait4(pid, &wstatus, 0, 0) == -1) {
+      if (errno != EINTR) {
+        wstatus = -1;
+        break;
+      }
+    }
+    ALLOW_CANCELATION;
+    sigaction(SIGQUIT, &savequit, 0);
+    sigaction(SIGINT, &saveint, 0);
+  }
+  sigprocmask(SIG_SETMASK, &savemask, 0);
+  return wstatus;
+}