/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <grpc/support/port_platform.h>

#ifdef GPR_POSIX_SUBPROCESS

#include <grpc/support/subprocess.h>

#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include <grpc/support/alloc.h>
#include <grpc/support/log.h>

struct gpr_subprocess {
  int pid;
  bool joined;
};

const char *gpr_subprocess_binary_extension() { return ""; }

gpr_subprocess *gpr_subprocess_create(int argc, const char **argv) {
  gpr_subprocess *r;
  int pid;
  char **exec_args;

  pid = fork();
  if (pid == -1) {
    return NULL;
  } else if (pid == 0) {
    exec_args = (char **)gpr_malloc(((size_t)argc + 1) * sizeof(char *));
    memcpy(exec_args, argv, (size_t)argc * sizeof(char *));
    exec_args[argc] = NULL;
    execv(exec_args[0], exec_args);
    /* if we reach here, an error has occurred */
    gpr_log(GPR_ERROR, "execv '%s' failed: %s", exec_args[0], strerror(errno));
    _exit(1);
    return NULL;
  } else {
    r = (gpr_subprocess *)gpr_zalloc(sizeof(gpr_subprocess));
    r->pid = pid;
    return r;
  }
}

void gpr_subprocess_destroy(gpr_subprocess *p) {
  if (!p->joined) {
    kill(p->pid, SIGKILL);
    gpr_subprocess_join(p);
  }
  gpr_free(p);
}

int gpr_subprocess_join(gpr_subprocess *p) {
  int status;
retry:
  if (waitpid(p->pid, &status, 0) == -1) {
    if (errno == EINTR) {
      goto retry;
    }
    gpr_log(GPR_ERROR, "waitpid failed for pid %d: %s", p->pid,
            strerror(errno));
    return -1;
  }
  p->joined = true;
  return status;
}

void gpr_subprocess_interrupt(gpr_subprocess *p) {
  if (!p->joined) {
    kill(p->pid, SIGINT);
  }
}

#endif /* GPR_POSIX_SUBPROCESS */