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

2025-06-26 22:38:30 +00:00 · 2024-11-15 20:37:34 -08:00 · 2024-11-15 20:37:34 -08:00 · cafdb456ed
commit cafdb456ed
parent 4e9566cd33
24 changed files with 216 additions and 59 deletions
--- a/libc/system/popen.c
+++ b/libc/system/popen.c
@ -0,0 +1,124 @@
+/*-*- 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 2021 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/errno.h"
+#include "libc/intrin/weaken.h"
+#include "libc/paths.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/fflush.internal.h"
+#include "libc/stdio/internal.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/consts/f.h"
+#include "libc/sysv/consts/fd.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/thread/thread.h"
+
+/**
+ * Spawns subprocess and returns pipe stream.
+ *
+ * The returned resource needs to be passed to pclose().
+ *
+ * This embeds the Cosmopolitan Command Interpreter which provides
+ * Bourne-like syntax on all platforms including Windows.
+ *
+ * @param cmdline is a unix shell script
+ * @param mode can be:
+ *     - `"r"` for reading from subprocess standard output
+ *     - `"w"` for writing to subprocess standard input
+ *     - `"e"` for `O_CLOEXEC` on returned file
+ * @raise EINVAL if `mode` is invalid or specifies read+write
+ * @raise EMFILE if process `RLIMIT_NOFILE` has been reached
+ * @raise ENFILE if system-wide file limit has been reached
+ * @raise ECANCELED if thread was cancelled in masked mode
+ * @raise ENOMEM if we require more vespene gas
+ * @raise EAGAIN if `RLIMIT_NPROC` was exceeded
+ * @raise EINTR if signal was delivered
+ * @cancelationpoint
+ */
+FILE *popen(const char *cmdline, const char *mode) {
+  FILE *f, *f2;
+  int e, rc, pid, dir, flags, pipefds[2];
+  flags = fopenflags(mode);
+  if ((flags & O_ACCMODE) == O_RDONLY) {
+    dir = 0;
+  } else if ((flags & O_ACCMODE) == O_WRONLY) {
+    dir = 1;
+  } else {
+    einval();
+    return NULL;
+  }
+  if (_weaken(pthread_testcancel_np) &&
+      (rc = _weaken(pthread_testcancel_np)())) {
+    errno = rc;
+    return 0;
+  }
+  if (pipe2(pipefds, O_CLOEXEC) == -1)
+    return NULL;
+  if ((f = fdopen(pipefds[dir], mode))) {
+    switch ((pid = fork())) {
+      case 0:
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-fd-leak"
+        unassert(dup2(pipefds[!dir], !dir) == !dir);
+#pragma GCC diagnostic pop
+        // we can't rely on cloexec because cocmd builtins don't execve
+        if (pipefds[0] != !dir)
+          unassert(!close(pipefds[0]));
+        if (pipefds[1] != !dir)
+          unassert(!close(pipefds[1]));
+        // "The popen() function shall ensure that any streams from
+        //  previous popen() calls that remain open in the parent
+        //  process are closed in the new child process." -POSIX
+        for (int i = 0; i < __fflush.handles.i; ++i) {
+          if ((f2 = __fflush.handles.p[i]) && f2->pid) {
+            close(f2->fd);
+          }
+        }
+        _Exit(_cocmd(3,
+                     (char *[]){
+                         "popen",
+                         "-c",
+                         (char *)cmdline,
+                         0,
+                     },
+                     environ));
+      default:
+        f->pid = pid;
+        unassert(!close(pipefds[!dir]));
+        if (!(flags & O_CLOEXEC)) {
+          unassert(!fcntl(pipefds[dir], F_SETFD, 0));
+        }
+        return f;
+      case -1:
+        e = errno;
+        fclose(f);
+        close(pipefds[!dir]);
+        errno = e;
+        return NULL;
+    }
+  } else {
+    e = errno;
+    close(pipefds[0]);
+    close(pipefds[1]);
+    errno = e;
+    return NULL;
+  }
+}