run-command.h

   1 #ifndef RUN_COMMAND_H
   2 #define RUN_COMMAND_H
   3
   4 enum {
   5         ERR_RUN_COMMAND_FORK = 10000,
   6         ERR_RUN_COMMAND_EXEC,
   7         ERR_RUN_COMMAND_PIPE,
   8         ERR_RUN_COMMAND_WAITPID,
   9         ERR_RUN_COMMAND_WAITPID_WRONG_PID,
  10         ERR_RUN_COMMAND_WAITPID_SIGNAL,
  11         ERR_RUN_COMMAND_WAITPID_NOEXIT,
  12 };
  13
  14 struct child_process {
  15         const char **argv;
  16         pid_t pid;
  17         /*
  18          * Using .in, .out, .err:
  19          * - Specify 0 for no redirections (child inherits stdin, stdout,
  20          *   stderr from parent).
  21          * - Specify -1 to have a pipe allocated as follows:
  22          *     .in: returns the writable pipe end; parent writes to it,
  23          *          the readable pipe end becomes child's stdin
  24          *     .out, .err: returns the readable pipe end; parent reads from
  25          *          it, the writable pipe end becomes child's stdout/stderr
  26          *   The caller of start_command() must close the returned FDs
  27          *   after it has completed reading from/writing to it!
  28          * - Specify > 0 to set a channel to a particular FD as follows:
  29          *     .in: a readable FD, becomes child's stdin
  30          *     .out: a writable FD, becomes child's stdout/stderr
  31          *     .err > 0 not supported
  32          *   The specified FD is closed by start_command(), even in case
  33          *   of errors!
  34          */
  35         int in;
  36         int out;
  37         int err;
  38         const char *dir;
  39         const char *const *env;
  40         unsigned no_stdin:1;
  41         unsigned no_stdout:1;
  42         unsigned no_stderr:1;
  43         unsigned git_cmd:1; /* if this is to be git sub-command */
  44         unsigned stdout_to_stderr:1;
  45 };
  46
  47 int start_command(struct child_process *);
  48 int finish_command(struct child_process *);
  49 int run_command(struct child_process *);
  50
  51 #define RUN_COMMAND_NO_STDIN 1
  52 #define RUN_GIT_CMD          2  /*If this is to be git sub-command */
  53 #define RUN_COMMAND_STDOUT_TO_STDERR 4
  54 int run_command_v_opt(const char **argv, int opt);
  55 int run_command_v_opt_cd(const char **argv, int opt, const char *dir);
  56
  57 /*
  58  * env (the environment) is to be formatted like environ: "VAR=VALUE".
  59  * To unset an environment variable use just "VAR".
  60  */
  61 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
  62
  63 /*
  64  * The purpose of the following functions is to feed a pipe by running
  65  * a function asynchronously and providing output that the caller reads.
  66  *
  67  * It is expected that no synchronization and mutual exclusion between
  68  * the caller and the feed function is necessary so that the function
  69  * can run in a thread without interfering with the caller.
  70  */
  71 struct async {
  72         /*
  73          * proc writes to fd and closes it;
  74          * returns 0 on success, non-zero on failure
  75          */
  76         int (*proc)(int fd, void *data);
  77         void *data;
  78         int out;        /* caller reads from here and closes it */
  79         pid_t pid;
  80 };
  81
  82 int start_async(struct async *async);
  83 int finish_async(struct async *async);
  84
  85 #endif