run-command.h

   1 #ifndef RUN_COMMAND_H
   2 #define RUN_COMMAND_H
   3
   4 #ifndef NO_PTHREADS
   5 #include <pthread.h>
   6 #endif
   7
   8 #include "argv-array.h"
   9
  10 struct child_process {
  11         const char **argv;
  12         struct argv_array args;
  13         struct argv_array env_array;
  14         pid_t pid;
  15         /*
  16          * Using .in, .out, .err:
  17          * - Specify 0 for no redirections (child inherits stdin, stdout,
  18          *   stderr from parent).
  19          * - Specify -1 to have a pipe allocated as follows:
  20          *     .in: returns the writable pipe end; parent writes to it,
  21          *          the readable pipe end becomes child's stdin
  22          *     .out, .err: returns the readable pipe end; parent reads from
  23          *          it, the writable pipe end becomes child's stdout/stderr
  24          *   The caller of start_command() must close the returned FDs
  25          *   after it has completed reading from/writing to it!
  26          * - Specify > 0 to set a channel to a particular FD as follows:
  27          *     .in: a readable FD, becomes child's stdin
  28          *     .out: a writable FD, becomes child's stdout/stderr
  29          *     .err: a writable FD, becomes child's stderr
  30          *   The specified FD is closed by start_command(), even in case
  31          *   of errors!
  32          */
  33         int in;
  34         int out;
  35         int err;
  36         const char *dir;
  37         const char *const *env;
  38         unsigned no_stdin:1;
  39         unsigned no_stdout:1;
  40         unsigned no_stderr:1;
  41         unsigned git_cmd:1; /* if this is to be git sub-command */
  42         unsigned silent_exec_failure:1;
  43         unsigned stdout_to_stderr:1;
  44         unsigned use_shell:1;
  45         unsigned clean_on_exit:1;
  46         void (*clean_on_exit_handler)(struct child_process *process);
  47         void *clean_on_exit_handler_cbdata;
  48 };
  49
  50 #define CHILD_PROCESS_INIT { NULL, ARGV_ARRAY_INIT, ARGV_ARRAY_INIT }
  51 void child_process_init(struct child_process *);
  52 void child_process_clear(struct child_process *);
  53
  54 int start_command(struct child_process *);
  55 int finish_command(struct child_process *);
  56 int finish_command_in_signal(struct child_process *);
  57 int run_command(struct child_process *);
  58
  59 /*
  60  * Returns the path to the hook file, or NULL if the hook is missing
  61  * or disabled. Note that this points to static storage that will be
  62  * overwritten by further calls to find_hook and run_hook_*.
  63  */
  64 extern const char *find_hook(const char *name);
  65 LAST_ARG_MUST_BE_NULL
  66 extern int run_hook_le(const char *const *env, const char *name, ...);
  67 extern int run_hook_ve(const char *const *env, const char *name, va_list args);
  68
  69 #define RUN_COMMAND_NO_STDIN 1
  70 #define RUN_GIT_CMD          2  /*If this is to be git sub-command */
  71 #define RUN_COMMAND_STDOUT_TO_STDERR 4
  72 #define RUN_SILENT_EXEC_FAILURE 8
  73 #define RUN_USING_SHELL 16
  74 #define RUN_CLEAN_ON_EXIT 32
  75 int run_command_v_opt(const char **argv, int opt);
  76
  77 /*
  78  * env (the environment) is to be formatted like environ: "VAR=VALUE".
  79  * To unset an environment variable use just "VAR".
  80  */
  81 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
  82
  83 /**
  84  * Execute the given command, sending "in" to its stdin, and capturing its
  85  * stdout and stderr in the "out" and "err" strbufs. Any of the three may
  86  * be NULL to skip processing.
  87  *
  88  * Returns -1 if starting the command fails or reading fails, and otherwise
  89  * returns the exit code of the command. Any output collected in the
  90  * buffers is kept even if the command returns a non-zero exit. The hint fields
  91  * gives starting sizes for the strbuf allocations.
  92  *
  93  * The fields of "cmd" should be set up as they would for a normal run_command
  94  * invocation. But note that there is no need to set the in, out, or err
  95  * fields; pipe_command handles that automatically.
  96  */
  97 int pipe_command(struct child_process *cmd,
  98                  const char *in, size_t in_len,
  99                  struct strbuf *out, size_t out_hint,
 100                  struct strbuf *err, size_t err_hint);
 101
 102 /**
 103  * Convenience wrapper around pipe_command for the common case
 104  * of capturing only stdout.
 105  */
 106 static inline int capture_command(struct child_process *cmd,
 107                                   struct strbuf *out,
 108                                   size_t hint)
 109 {
 110         return pipe_command(cmd, NULL, 0, out, hint, NULL, 0);
 111 }
 112
 113 /*
 114  * The purpose of the following functions is to feed a pipe by running
 115  * a function asynchronously and providing output that the caller reads.
 116  *
 117  * It is expected that no synchronization and mutual exclusion between
 118  * the caller and the feed function is necessary so that the function
 119  * can run in a thread without interfering with the caller.
 120  */
 121 struct async {
 122         /*
 123          * proc reads from in; closes it before return
 124          * proc writes to out; closes it before return
 125          * returns 0 on success, non-zero on failure
 126          */
 127         int (*proc)(int in, int out, void *data);
 128         void *data;
 129         int in;         /* caller writes here and closes it */
 130         int out;        /* caller reads from here and closes it */
 131 #ifdef NO_PTHREADS
 132         pid_t pid;
 133 #else
 134         pthread_t tid;
 135         int proc_in;
 136         int proc_out;
 137 #endif
 138         int isolate_sigpipe;
 139 };
 140
 141 int start_async(struct async *async);
 142 int finish_async(struct async *async);
 143 int in_async(void);
 144 void check_pipe(int err);
 145
 146 /**
 147  * This callback should initialize the child process and preload the
 148  * error channel if desired. The preloading of is useful if you want to
 149  * have a message printed directly before the output of the child process.
 150  * pp_cb is the callback cookie as passed to run_processes_parallel.
 151  * You can store a child process specific callback cookie in pp_task_cb.
 152  *
 153  * Even after returning 0 to indicate that there are no more processes,
 154  * this function will be called again until there are no more running
 155  * child processes.
 156  *
 157  * Return 1 if the next child is ready to run.
 158  * Return 0 if there are currently no more tasks to be processed.
 159  * To send a signal to other child processes for abortion,
 160  * return the negative signal number.
 161  */
 162 typedef int (*get_next_task_fn)(struct child_process *cp,
 163                                 struct strbuf *out,
 164                                 void *pp_cb,
 165                                 void **pp_task_cb);
 166
 167 /**
 168  * This callback is called whenever there are problems starting
 169  * a new process.
 170  *
 171  * You must not write to stdout or stderr in this function. Add your
 172  * message to the strbuf out instead, which will be printed without
 173  * messing up the output of the other parallel processes.
 174  *
 175  * pp_cb is the callback cookie as passed into run_processes_parallel,
 176  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 177  *
 178  * Return 0 to continue the parallel processing. To abort return non zero.
 179  * To send a signal to other child processes for abortion, return
 180  * the negative signal number.
 181  */
 182 typedef int (*start_failure_fn)(struct strbuf *out,
 183                                 void *pp_cb,
 184                                 void *pp_task_cb);
 185
 186 /**
 187  * This callback is called on every child process that finished processing.
 188  *
 189  * You must not write to stdout or stderr in this function. Add your
 190  * message to the strbuf out instead, which will be printed without
 191  * messing up the output of the other parallel processes.
 192  *
 193  * pp_cb is the callback cookie as passed into run_processes_parallel,
 194  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 195  *
 196  * Return 0 to continue the parallel processing.  To abort return non zero.
 197  * To send a signal to other child processes for abortion, return
 198  * the negative signal number.
 199  */
 200 typedef int (*task_finished_fn)(int result,
 201                                 struct strbuf *out,
 202                                 void *pp_cb,
 203                                 void *pp_task_cb);
 204
 205 /**
 206  * Runs up to n processes at the same time. Whenever a process can be
 207  * started, the callback get_next_task_fn is called to obtain the data
 208  * required to start another child process.
 209  *
 210  * The children started via this function run in parallel. Their output
 211  * (both stdout and stderr) is routed to stderr in a manner that output
 212  * from different tasks does not interleave.
 213  *
 214  * start_failure_fn and task_finished_fn can be NULL to omit any
 215  * special handling.
 216  */
 217 int run_processes_parallel(int n,
 218                            get_next_task_fn,
 219                            start_failure_fn,
 220                            task_finished_fn,
 221                            void *pp_cb);
 222
 223 #endif