Adding upstream version 1.21.4.upstream/1.21.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 370 insertions, 0 deletions

diff --git a/lib/wait-process.c b/lib/wait-process.c
new file mode 100644
index 0000000..3e95b4e
--- /dev/null
+++ b/lib/wait-process.c
@@ -0,0 +1,370 @@
+/* Waiting for a subprocess to finish.
+   Copyright (C) 2001-2003, 2005-2023 Free Software Foundation, Inc.
+   Written by Bruno Haible <haible@clisp.cons.org>, 2001.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+
+#include <config.h>
+
+/* Specification.  */
+#include "wait-process.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "error.h"
+#include "fatal-signal.h"
+#include "xalloc.h"
+#include "gettext.h"
+
+#define _(str) gettext (str)
+
+#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
+
+
+#if defined _WIN32 && ! defined __CYGWIN__
+
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+
+/* The return value of _spawnvp() is really a process handle as returned
+   by CreateProcess().  Therefore we can kill it using TerminateProcess.  */
+# define kill(pid,sig) TerminateProcess ((HANDLE) (pid), sig)
+
+#endif
+
+
+/* Type of an entry in the slaves array.
+   The 'used' bit determines whether this entry is currently in use.
+   (If pid_t was an atomic type like sig_atomic_t, we could just set the
+   'child' field to 0 when unregistering a slave process, and wouldn't need
+   the 'used' field.)
+   The 'used' and 'child' fields are accessed from within the cleanup_slaves()
+   action, therefore we mark them as 'volatile'.  */
+typedef struct
+{
+  volatile sig_atomic_t used;
+  volatile pid_t child;
+}
+slaves_entry_t;
+
+/* The registered slave subprocesses.  */
+static slaves_entry_t static_slaves[32];
+static slaves_entry_t * volatile slaves = static_slaves;
+static sig_atomic_t volatile slaves_count = 0;
+static size_t slaves_allocated = SIZEOF (static_slaves);
+
+/* The termination signal for slave subprocesses.
+   2003-10-07:  Terminator becomes Governator.  */
+#ifdef SIGHUP
+# define TERMINATOR SIGHUP
+#else
+# define TERMINATOR SIGTERM
+#endif
+
+/* The cleanup action.  It gets called asynchronously.  */
+static _GL_ASYNC_SAFE void
+cleanup_slaves (void)
+{
+  for (;;)
+    {
+      /* Get the last registered slave.  */
+      size_t n = slaves_count;
+      if (n == 0)
+        break;
+      n--;
+      slaves_count = n;
+      /* Skip unused entries in the slaves array.  */
+      if (slaves[n].used)
+        {
+          pid_t slave = slaves[n].child;
+
+          /* Kill the slave.  */
+          kill (slave, TERMINATOR);
+        }
+    }
+}
+
+/* The cleanup action, taking a signal argument.
+   It gets called asynchronously.  */
+static _GL_ASYNC_SAFE void
+cleanup_slaves_action (_GL_UNUSED int sig)
+{
+  cleanup_slaves ();
+}
+
+/* Register a subprocess as being a slave process.  This means that the
+   subprocess will be terminated when its creator receives a catchable fatal
+   signal or exits normally.  Registration ends when wait_subprocess()
+   notices that the subprocess has exited.  */
+void
+register_slave_subprocess (pid_t child)
+{
+  static bool cleanup_slaves_registered = false;
+  if (!cleanup_slaves_registered)
+    {
+      atexit (cleanup_slaves);
+      if (at_fatal_signal (cleanup_slaves_action) < 0)
+        xalloc_die ();
+      cleanup_slaves_registered = true;
+    }
+
+  /* Try to store the new slave in an unused entry of the slaves array.  */
+  {
+    slaves_entry_t *s = slaves;
+    slaves_entry_t *s_end = s + slaves_count;
+
+    for (; s < s_end; s++)
+      if (!s->used)
+        {
+          /* The two uses of 'volatile' in the slaves_entry_t type above
+             (and ISO C 99 section 5.1.2.3.(5)) ensure that we mark the
+             entry as used only after the child pid has been written to the
+             memory location s->child.  */
+          s->child = child;
+          s->used = 1;
+          return;
+        }
+  }
+
+  if (slaves_count == slaves_allocated)
+    {
+      /* Extend the slaves array.  Note that we cannot use xrealloc(),
+         because then the cleanup_slaves() function could access an already
+         deallocated array.  */
+      slaves_entry_t *old_slaves = slaves;
+      size_t new_slaves_allocated = 2 * slaves_allocated;
+      slaves_entry_t *new_slaves =
+        (slaves_entry_t *)
+        malloc (new_slaves_allocated * sizeof (slaves_entry_t));
+      if (new_slaves == NULL)
+        {
+          /* xalloc_die() will call exit() which will invoke cleanup_slaves().
+             Additionally we need to kill child, because it's not yet among
+             the slaves list.  */
+          kill (child, TERMINATOR);
+          xalloc_die ();
+        }
+      memcpy (new_slaves, old_slaves,
+              slaves_allocated * sizeof (slaves_entry_t));
+      slaves = new_slaves;
+      slaves_allocated = new_slaves_allocated;
+      /* Now we can free the old slaves array.  */
+      if (old_slaves != static_slaves)
+        free (old_slaves);
+    }
+  /* The three uses of 'volatile' in the types above (and ISO C 99 section
+     5.1.2.3.(5)) ensure that we increment the slaves_count only after the
+     new slave and its 'used' bit have been written to the memory locations
+     that make up slaves[slaves_count].  */
+  slaves[slaves_count].child = child;
+  slaves[slaves_count].used = 1;
+  slaves_count++;
+}
+
+/* Unregister a child from the list of slave subprocesses.  */
+static void
+unregister_slave_subprocess (pid_t child)
+{
+  /* The easiest way to remove an entry from a list that can be used by
+     an asynchronous signal handler is just to mark it as unused.  For this,
+     we rely on sig_atomic_t.  */
+  slaves_entry_t *s = slaves;
+  slaves_entry_t *s_end = s + slaves_count;
+
+  for (; s < s_end; s++)
+    if (s->used && s->child == child)
+      s->used = 0;
+}
+
+
+/* Wait for a subprocess to finish.  Return its exit code.
+   If it didn't terminate correctly, exit if exit_on_error is true, otherwise
+   return 127.  */
+int
+wait_subprocess (pid_t child, const char *progname,
+                 bool ignore_sigpipe, bool null_stderr,
+                 bool slave_process, bool exit_on_error,
+                 int *termsigp)
+{
+#if HAVE_WAITID && defined WNOWAIT && 0
+  /* Commented out because waitid() without WEXITED and with WNOWAIT doesn't
+     work: On Solaris 7 and OSF/1 4.0, it returns -1 and sets errno = ECHILD,
+     and on HP-UX 10.20 it just hangs.  */
+  /* Use of waitid() with WNOWAIT avoids a race condition: If slave_process is
+     true, and this process sleeps a very long time between the return from
+     waitpid() and the execution of unregister_slave_subprocess(), and
+     meanwhile another process acquires the same PID as child, and then - still
+     before unregister_slave_subprocess() - this process gets a fatal signal,
+     it would kill the other totally unrelated process.  */
+  siginfo_t info;
+
+  if (termsigp != NULL)
+    *termsigp = 0;
+  for (;;)
+    {
+      if (waitid (P_PID, child, &info, WEXITED | (slave_process ? WNOWAIT : 0))
+          < 0)
+        {
+# ifdef EINTR
+          if (errno == EINTR)
+            continue;
+# endif
+          if (exit_on_error || !null_stderr)
+            error (exit_on_error ? EXIT_FAILURE : 0, errno,
+                   _("%s subprocess"), progname);
+          return 127;
+        }
+
+      /* info.si_code is set to one of CLD_EXITED, CLD_KILLED, CLD_DUMPED,
+         CLD_TRAPPED, CLD_STOPPED, CLD_CONTINUED.  Loop until the program
+         terminates.  */
+      if (info.si_code == CLD_EXITED
+          || info.si_code == CLD_KILLED || info.si_code == CLD_DUMPED)
+        break;
+    }
+
+  /* The child process has exited or was signalled.  */
+
+  if (slave_process)
+    {
+      /* Unregister the child from the list of slave subprocesses, so that
+         later, when we exit, we don't kill a totally unrelated process which
+         may have acquired the same pid.  */
+      unregister_slave_subprocess (child);
+
+      /* Now remove the zombie from the process list.  */
+      for (;;)
+        {
+          if (waitid (P_PID, child, &info, WEXITED) < 0)
+            {
+# ifdef EINTR
+              if (errno == EINTR)
+                continue;
+# endif
+              if (exit_on_error || !null_stderr)
+                error (exit_on_error ? EXIT_FAILURE : 0, errno,
+                       _("%s subprocess"), progname);
+              return 127;
+            }
+          break;
+        }
+    }
+
+  switch (info.si_code)
+    {
+    case CLD_KILLED:
+    case CLD_DUMPED:
+      if (termsigp != NULL)
+        *termsigp = info.si_status; /* TODO: or info.si_signo? */
+# ifdef SIGPIPE
+      if (info.si_status == SIGPIPE && ignore_sigpipe)
+        return 0;
+# endif
+      if (exit_on_error || (!null_stderr && termsigp == NULL))
+        error (exit_on_error ? EXIT_FAILURE : 0, 0,
+               _("%s subprocess got fatal signal %d"),
+               progname, info.si_status);
+      return 127;
+    case CLD_EXITED:
+      if (info.si_status == 127)
+        {
+          if (exit_on_error || !null_stderr)
+            error (exit_on_error ? EXIT_FAILURE : 0, 0,
+                   _("%s subprocess failed"), progname);
+          return 127;
+        }
+      return info.si_status;
+    default:
+      abort ();
+    }
+#else
+  /* waitpid() is just as portable as wait() nowadays.  */
+  int status;
+
+  if (termsigp != NULL)
+    *termsigp = 0;
+  status = 0;
+  for (;;)
+    {
+      int result = waitpid (child, &status, 0);
+
+      if (result != child)
+        {
+# ifdef EINTR
+          if (errno == EINTR)
+            continue;
+# endif
+# if 0 /* defined ECHILD */
+          if (errno == ECHILD)
+            {
+              /* Child process nonexistent?! Assume it terminated
+                 successfully.  */
+              status = 0;
+              break;
+            }
+# endif
+          if (exit_on_error || !null_stderr)
+            error (exit_on_error ? EXIT_FAILURE : 0, errno,
+                   _("%s subprocess"), progname);
+          return 127;
+        }
+
+      /* One of WIFSIGNALED (status), WIFEXITED (status), WIFSTOPPED (status)
+         must always be true, since we did not specify WCONTINUED in the
+         waitpid() call.  Loop until the program terminates.  */
+      if (!WIFSTOPPED (status))
+        break;
+    }
+
+  /* The child process has exited or was signalled.  */
+
+  if (slave_process)
+    /* Unregister the child from the list of slave subprocesses, so that
+       later, when we exit, we don't kill a totally unrelated process which
+       may have acquired the same pid.  */
+    unregister_slave_subprocess (child);
+
+  if (WIFSIGNALED (status))
+    {
+      if (termsigp != NULL)
+        *termsigp = WTERMSIG (status);
+# ifdef SIGPIPE
+      if (WTERMSIG (status) == SIGPIPE && ignore_sigpipe)
+        return 0;
+# endif
+      if (exit_on_error || (!null_stderr && termsigp == NULL))
+        error (exit_on_error ? EXIT_FAILURE : 0, 0,
+               _("%s subprocess got fatal signal %d"),
+               progname, (int) WTERMSIG (status));
+      return 127;
+    }
+  if (!WIFEXITED (status))
+    abort ();
+  if (WEXITSTATUS (status) == 127)
+    {
+      if (exit_on_error || !null_stderr)
+        error (exit_on_error ? EXIT_FAILURE : 0, 0,
+               _("%s subprocess failed"), progname);
+      return 127;
+    }
+  return WEXITSTATUS (status);
+#endif
+}