/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SUBCMD_RUN_COMMAND_H
#define __SUBCMD_RUN_COMMAND_H

#include <unistd.h>

enum {
    ERR_RUN_COMMAND_FORK = 10000,
    ERR_RUN_COMMAND_EXEC,
    ERR_RUN_COMMAND_PIPE,
    ERR_RUN_COMMAND_WAITPID,
    ERR_RUN_COMMAND_WAITPID_WRONG_PID,
    ERR_RUN_COMMAND_WAITPID_SIGNAL,
    ERR_RUN_COMMAND_WAITPID_NOEXIT,
};
#define IS_RUN_COMMAND_ERR(x) (-(x) >= ERR_RUN_COMMAND_FORK)

struct child_process {
    const char **argv;
    pid_t pid;
    /*
     * Using .in, .out, .err:
     * - Specify 0 for no redirections (child inherits stdin, stdout,
     *   stderr from parent).
     * - Specify -1 to have a pipe allocated as follows:
     *     .in: returns the writable pipe end; parent writes to it,
     *          the readable pipe end becomes child's stdin
     *     .out, .err: returns the readable pipe end; parent reads from
     *          it, the writable pipe end becomes child's stdout/stderr
     *   The caller of start_command() must close the returned FDs
     *   after it has completed reading from/writing to it!
     * - Specify > 0 to set a channel to a particular FD as follows:
     *     .in: a readable FD, becomes child's stdin
     *     .out: a writable FD, becomes child's stdout/stderr
     *     .err > 0 not supported
     *   The specified FD is closed by start_command(), even in case
     *   of errors!
     */
    int in;
    int out;
    int err;
    const char *dir;
    const char *const *env;
    unsigned no_stdin:1;
    unsigned no_stdout:1;
    unsigned no_stderr:1;
    unsigned exec_cmd:1; /* if this is to be external sub-command */
    unsigned stdout_to_stderr:1;
    void (*preexec_cb)(void);
};

int start_command(struct child_process *);
int finish_command(struct child_process *);
int run_command(struct child_process *);

#define RUN_COMMAND_NO_STDIN 1
#define RUN_EXEC_CMD         2    /*If this is to be external sub-command */
#define RUN_COMMAND_STDOUT_TO_STDERR 4
int run_command_v_opt(const char **argv, int opt);

#endif /* __SUBCMD_RUN_COMMAND_H */