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