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, capturing its stdout in the given strbuf.
  83  * Returns -1 if starting the command fails or reading fails, and otherwise
  84  * returns the exit code of the command. The output collected in the
  85  * buffer is kept even if the command returns a non-zero exit. The hint field
  86  * gives a starting size for the strbuf allocation.
  87  *
  88  * The fields of "cmd" should be set up as they would for a normal run_command
  89  * invocation. But note that there is no need to set cmd->out; the function
  90  * sets it up for the caller.
  91  */
  92 int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint);
  93
  94 /*
  95  * The purpose of the following functions is to feed a pipe by running
  96  * a function asynchronously and providing output that the caller reads.
  97  *
  98  * It is expected that no synchronization and mutual exclusion between
  99  * the caller and the feed function is necessary so that the function
 100  * can run in a thread without interfering with the caller.
 101  */
 102 struct async {
 103         /*
 104          * proc reads from in; closes it before return
 105          * proc writes to out; closes it before return
 106          * returns 0 on success, non-zero on failure
 107          */
 108         int (*proc)(int in, int out, void *data);
 109         void *data;
 110         int in;         /* caller writes here and closes it */
 111         int out;        /* caller reads from here and closes it */
 112 #ifdef NO_PTHREADS
 113         pid_t pid;
 114 #else
 115         pthread_t tid;
 116         int proc_in;
 117         int proc_out;
 118 #endif
 119 };
 120
 121 int start_async(struct async *async);
 122 int finish_async(struct async *async);
 123 int in_async(void);
 124 void NORETURN async_exit(int code);
 125
 126 /**
 127  * This callback should initialize the child process and preload the
 128  * error channel if desired. The preloading of is useful if you want to
 129  * have a message printed directly before the output of the child process.
 130  * pp_cb is the callback cookie as passed to run_processes_parallel.
 131  * You can store a child process specific callback cookie in pp_task_cb.
 132  *
 133  * Even after returning 0 to indicate that there are no more processes,
 134  * this function will be called again until there are no more running
 135  * child processes.
 136  *
 137  * Return 1 if the next child is ready to run.
 138  * Return 0 if there are currently no more tasks to be processed.
 139  * To send a signal to other child processes for abortion,
 140  * return the negative signal number.
 141  */
 142 typedef int (*get_next_task_fn)(struct child_process *cp,
 143                                 struct strbuf *err,
 144                                 void *pp_cb,
 145                                 void **pp_task_cb);
 146
 147 /**
 148  * This callback is called whenever there are problems starting
 149  * a new process.
 150  *
 151  * You must not write to stdout or stderr in this function. Add your
 152  * message to the strbuf err instead, which will be printed without
 153  * messing up the output of the other parallel processes.
 154  *
 155  * pp_cb is the callback cookie as passed into run_processes_parallel,
 156  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 157  *
 158  * Return 0 to continue the parallel processing. To abort return non zero.
 159  * To send a signal to other child processes for abortion, return
 160  * the negative signal number.
 161  */
 162 typedef int (*start_failure_fn)(struct child_process *cp,
 163                                 struct strbuf *err,
 164                                 void *pp_cb,
 165                                 void *pp_task_cb);
 166
 167 /**
 168  * This callback is called on every child process that finished processing.
 169  *
 170  * You must not write to stdout or stderr in this function. Add your
 171  * message to the strbuf err instead, which will be printed without
 172  * messing up the output of the other parallel processes.
 173  *
 174  * pp_cb is the callback cookie as passed into run_processes_parallel,
 175  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 176  *
 177  * Return 0 to continue the parallel processing.  To abort return non zero.
 178  * To send a signal to other child processes for abortion, return
 179  * the negative signal number.
 180  */
 181 typedef int (*task_finished_fn)(int result,
 182                                 struct child_process *cp,
 183                                 struct strbuf *err,
 184                                 void *pp_cb,
 185                                 void *pp_task_cb);
 186
 187 /**
 188  * Runs up to n processes at the same time. Whenever a process can be
 189  * started, the callback get_next_task_fn is called to obtain the data
 190  * required to start another child process.
 191  *
 192  * The children started via this function run in parallel. Their output
 193  * (both stdout and stderr) is routed to stderr in a manner that output
 194  * from different tasks does not interleave.
 195  *
 196  * If start_failure_fn or task_finished_fn are NULL, default handlers
 197  * will be used. The default handlers will print an error message on
 198  * error without issuing an emergency stop.
 199  */
 200 int run_processes_parallel(int n,
 201                            get_next_task_fn,
 202                            start_failure_fn,
 203                            task_finished_fn,
 204                            void *pp_cb);
 205
 206 #endif