// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

#include <fs-management/mount.h>
#include <lib/fdio/io.h>
#include <lib/fdio/spawn.h>
#include <lib/fdio/util.h>
#include <lib/zx/process.h>
#include <zircon/compiler.h>
#include <zircon/processargs.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>

namespace {

void InitArgvAndActions(int argc, const char** argv, zx_handle_t* handles,
                        uint32_t* types, size_t len,
                        const char** null_terminated_argv_out,
                        fdio_spawn_action_t* actions_out) {
    for (int i = 0; i < argc; ++i) {
        null_terminated_argv_out[i] = argv[i];
    }
    null_terminated_argv_out[argc] = nullptr;

    for (size_t i = 0; i < len; ++i) {
        actions_out[i].action = FDIO_SPAWN_ACTION_ADD_HANDLE;
        actions_out[i].h.id = types[i];
        actions_out[i].h.handle = handles[i];
    }
}

constexpr size_t kMaxStdioActions = 1;

enum class StdioType {
    kLog,
    kClone,
    kNone,
};

// Initializes Stdio.
//
// If necessary, updates the |actions| which will be sent to fdio_spawn.
// |action_count| is an in/out parameter which may be increased if an action is
// added.
// |flags| is an in/out parameter which may be modified to alter the cloning of
// STDIO.
void InitStdio(StdioType stdio, fdio_spawn_action_t* actions,
               size_t* action_count, uint32_t* flags) {
    switch (stdio) {
    case StdioType::kLog:
        zx_handle_t h;
        zx_debuglog_create(ZX_HANDLE_INVALID, 0, &h);
        if (h != ZX_HANDLE_INVALID) {
            actions[*action_count].action = FDIO_SPAWN_ACTION_ADD_HANDLE;
            actions[*action_count].h.id = PA_HND(PA_FDIO_LOGGER, FDIO_FLAG_USE_FOR_STDIO);
            actions[*action_count].h.handle = h;
            *action_count += 1;
        }
        *flags &= ~FDIO_SPAWN_CLONE_STDIO;
        break;
    case StdioType::kClone:
        *flags |= FDIO_SPAWN_CLONE_STDIO;
        break;
    case StdioType::kNone:
        *flags &= ~FDIO_SPAWN_CLONE_STDIO;
        break;
    }
}

enum class ProcessAction {
    kBlock,
    kNonBlock,
};

// Spawns a process.
//
// Optionally blocks, waiting for the process to terminate, depending
// the value provided in |block|.
zx_status_t Spawn(ProcessAction proc_action, uint32_t flags, const char** argv,
                  size_t action_count, const fdio_spawn_action_t* actions) {
    zx::process proc;
    char err_msg[FDIO_SPAWN_ERR_MSG_MAX_LENGTH];
    zx_status_t status = fdio_spawn_etc(ZX_HANDLE_INVALID, flags, argv[0], argv, nullptr,
                                        action_count, actions, proc.reset_and_get_address(),
                                        err_msg);
    if (status != ZX_OK) {
        fprintf(stderr, "fs-management: Cannot spawn %s: %d (%s): %s\n",
                argv[0], status, zx_status_get_string(status), err_msg);
        return status;
    }

    if (proc_action == ProcessAction::kBlock) {
        status = proc.wait_one(ZX_PROCESS_TERMINATED, zx::time::infinite(), nullptr);
        if (status != ZX_OK) {
            fprintf(stderr, "spawn: Error waiting for process to terminate\n");
            return status;
        }

        zx_info_process_t info;
        status = proc.get_info(ZX_INFO_PROCESS, &info, sizeof(info), nullptr, nullptr);
        if (status != ZX_OK) {
            fprintf(stderr, "spawn: Failed to get process info\n");
            return status;
        }

        if (!info.exited || info.return_code != 0) {
            return ZX_ERR_BAD_STATE;
        }
    }
    return ZX_OK;
}

zx_status_t Launch(StdioType stdio, ProcessAction proc_action, int argc,
                   const char** argv, zx_handle_t* handles, uint32_t* types, size_t len) {
    const char* null_terminated_argv[argc + 1];
    fdio_spawn_action_t actions[len + kMaxStdioActions];
    InitArgvAndActions(argc, argv, handles, types, len, null_terminated_argv, actions);

    size_t action_count = len;
    uint32_t flags = FDIO_SPAWN_CLONE_ALL;
    InitStdio(stdio, actions, &action_count, &flags);

    return Spawn(proc_action, flags, null_terminated_argv, action_count, actions);
}

}  // namespace

zx_status_t launch_silent_sync(int argc, const char** argv, zx_handle_t* handles,
                               uint32_t* types, size_t len) {
    return Launch(StdioType::kNone, ProcessAction::kBlock, argc, argv, handles, types, len);
}

zx_status_t launch_silent_async(int argc, const char** argv, zx_handle_t* handles,
                                uint32_t* types, size_t len) {
    return Launch(StdioType::kNone, ProcessAction::kNonBlock, argc, argv, handles, types, len);
}

zx_status_t launch_stdio_sync(int argc, const char** argv, zx_handle_t* handles,
                              uint32_t* types, size_t len) {
    return Launch(StdioType::kClone, ProcessAction::kBlock, argc, argv, handles, types, len);
}

zx_status_t launch_stdio_async(int argc, const char** argv, zx_handle_t* handles,
                               uint32_t* types, size_t len) {
    return Launch(StdioType::kClone, ProcessAction::kNonBlock, argc, argv, handles, types, len);
}

zx_status_t launch_logs_async(int argc, const char** argv, zx_handle_t* handles,
                              uint32_t* types, size_t len) {
    return Launch(StdioType::kLog, ProcessAction::kNonBlock, argc, argv, handles, types, len);
}