run-command.h

   1 #ifndef RUN_COMMAND_H
   2 #define RUN_COMMAND_H
   3
   4 #include "thread-utils.h"
   5
   6 #include "argv-array.h"
   7
   8 struct child_process {
   9         const char **argv;
  10         struct argv_array args;
  11         struct argv_array env_array;
  12         pid_t pid;
  13
  14         int trace2_child_id;
  15         uint64_t trace2_child_us_start;
  16         const char *trace2_child_class;
  17         const char *trace2_hook_name;
  18
  19         /*
  20          * Using .in, .out, .err:
  21          * - Specify 0 for no redirections (child inherits stdin, stdout,
  22          *   stderr from parent).
  23          * - Specify -1 to have a pipe allocated as follows:
  24          *     .in: returns the writable pipe end; parent writes to it,
  25          *          the readable pipe end becomes child's stdin
  26          *     .out, .err: returns the readable pipe end; parent reads from
  27          *          it, the writable pipe end becomes child's stdout/stderr
  28          *   The caller of start_command() must close the returned FDs
  29          *   after it has completed reading from/writing to it!
  30          * - Specify > 0 to set a channel to a particular FD as follows:
  31          *     .in: a readable FD, becomes child's stdin
  32          *     .out: a writable FD, becomes child's stdout/stderr
  33          *     .err: a writable FD, becomes child's stderr
  34          *   The specified FD is closed by start_command(), even in case
  35          *   of errors!
  36          */
  37         int in;
  38         int out;
  39         int err;
  40         const char *dir;
  41         const char *const *env;
  42         unsigned no_stdin:1;
  43         unsigned no_stdout:1;
  44         unsigned no_stderr:1;
  45         unsigned git_cmd:1; /* if this is to be git sub-command */
  46         unsigned silent_exec_failure:1;
  47         unsigned stdout_to_stderr:1;
  48         unsigned use_shell:1;
  49         unsigned clean_on_exit:1;
  50         unsigned wait_after_clean:1;
  51         void (*clean_on_exit_handler)(struct child_process *process);
  52         void *clean_on_exit_handler_cbdata;
  53 };
  54
  55 #define CHILD_PROCESS_INIT { NULL, ARGV_ARRAY_INIT, ARGV_ARRAY_INIT }
  56 void child_process_init(struct child_process *);
  57 void child_process_clear(struct child_process *);
  58 int is_executable(const char *name);
  59
  60 int start_command(struct child_process *);
  61 int finish_command(struct child_process *);
  62 int finish_command_in_signal(struct child_process *);
  63 int run_command(struct child_process *);
  64
  65 /*
  66  * Returns the path to the hook file, or NULL if the hook is missing
  67  * or disabled. Note that this points to static storage that will be
  68  * overwritten by further calls to find_hook and run_hook_*.
  69  */
  70 const char *find_hook(const char *name);
  71 LAST_ARG_MUST_BE_NULL
  72 int run_hook_le(const char *const *env, const char *name, ...);
  73 int run_hook_ve(const char *const *env, const char *name, va_list args);
  74
  75 #define RUN_COMMAND_NO_STDIN 1
  76 #define RUN_GIT_CMD          2  /*If this is to be git sub-command */
  77 #define RUN_COMMAND_STDOUT_TO_STDERR 4
  78 #define RUN_SILENT_EXEC_FAILURE 8
  79 #define RUN_USING_SHELL 16
  80 #define RUN_CLEAN_ON_EXIT 32
  81 int run_command_v_opt(const char **argv, int opt);
  82 int run_command_v_opt_tr2(const char **argv, int opt, const char *tr2_class);
  83 /*
  84  * env (the environment) is to be formatted like environ: "VAR=VALUE".
  85  * To unset an environment variable use just "VAR".
  86  */
  87 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
  88 int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
  89                                  const char *const *env, const char *tr2_class);
  90
  91 /**
  92  * Execute the given command, sending "in" to its stdin, and capturing its
  93  * stdout and stderr in the "out" and "err" strbufs. Any of the three may
  94  * be NULL to skip processing.
  95  *
  96  * Returns -1 if starting the command fails or reading fails, and otherwise
  97  * returns the exit code of the command. Any output collected in the
  98  * buffers is kept even if the command returns a non-zero exit. The hint fields
  99  * gives starting sizes for the strbuf allocations.
 100  *
 101  * The fields of "cmd" should be set up as they would for a normal run_command
 102  * invocation. But note that there is no need to set the in, out, or err
 103  * fields; pipe_command handles that automatically.
 104  */
 105 int pipe_command(struct child_process *cmd,
 106                  const char *in, size_t in_len,
 107                  struct strbuf *out, size_t out_hint,
 108                  struct strbuf *err, size_t err_hint);
 109
 110 /**
 111  * Convenience wrapper around pipe_command for the common case
 112  * of capturing only stdout.
 113  */
 114 static inline int capture_command(struct child_process *cmd,
 115                                   struct strbuf *out,
 116                                   size_t hint)
 117 {
 118         return pipe_command(cmd, NULL, 0, out, hint, NULL, 0);
 119 }
 120
 121 /*
 122  * The purpose of the following functions is to feed a pipe by running
 123  * a function asynchronously and providing output that the caller reads.
 124  *
 125  * It is expected that no synchronization and mutual exclusion between
 126  * the caller and the feed function is necessary so that the function
 127  * can run in a thread without interfering with the caller.
 128  */
 129 struct async {
 130         /*
 131          * proc reads from in; closes it before return
 132          * proc writes to out; closes it before return
 133          * returns 0 on success, non-zero on failure
 134          */
 135         int (*proc)(int in, int out, void *data);
 136         void *data;
 137         int in;         /* caller writes here and closes it */
 138         int out;        /* caller reads from here and closes it */
 139 #ifdef NO_PTHREADS
 140         pid_t pid;
 141 #else
 142         pthread_t tid;
 143         int proc_in;
 144         int proc_out;
 145 #endif
 146         int isolate_sigpipe;
 147 };
 148
 149 int start_async(struct async *async);
 150 int finish_async(struct async *async);
 151 int in_async(void);
 152 int async_with_fork(void);
 153 void check_pipe(int err);
 154
 155 /**
 156  * This callback should initialize the child process and preload the
 157  * error channel if desired. The preloading of is useful if you want to
 158  * have a message printed directly before the output of the child process.
 159  * pp_cb is the callback cookie as passed to run_processes_parallel.
 160  * You can store a child process specific callback cookie in pp_task_cb.
 161  *
 162  * Even after returning 0 to indicate that there are no more processes,
 163  * this function will be called again until there are no more running
 164  * child processes.
 165  *
 166  * Return 1 if the next child is ready to run.
 167  * Return 0 if there are currently no more tasks to be processed.
 168  * To send a signal to other child processes for abortion,
 169  * return the negative signal number.
 170  */
 171 typedef int (*get_next_task_fn)(struct child_process *cp,
 172                                 struct strbuf *out,
 173                                 void *pp_cb,
 174                                 void **pp_task_cb);
 175
 176 /**
 177  * This callback is called whenever there are problems starting
 178  * a new process.
 179  *
 180  * You must not write to stdout or stderr in this function. Add your
 181  * message to the strbuf out instead, which will be printed without
 182  * messing up the output of the other parallel processes.
 183  *
 184  * pp_cb is the callback cookie as passed into run_processes_parallel,
 185  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 186  *
 187  * Return 0 to continue the parallel processing. To abort return non zero.
 188  * To send a signal to other child processes for abortion, return
 189  * the negative signal number.
 190  */
 191 typedef int (*start_failure_fn)(struct strbuf *out,
 192                                 void *pp_cb,
 193                                 void *pp_task_cb);
 194
 195 /**
 196  * This callback is called on every child process that finished processing.
 197  *
 198  * You must not write to stdout or stderr in this function. Add your
 199  * message to the strbuf out instead, which will be printed without
 200  * messing up the output of the other parallel processes.
 201  *
 202  * pp_cb is the callback cookie as passed into run_processes_parallel,
 203  * pp_task_cb is the callback cookie as passed into get_next_task_fn.
 204  *
 205  * Return 0 to continue the parallel processing.  To abort return non zero.
 206  * To send a signal to other child processes for abortion, return
 207  * the negative signal number.
 208  */
 209 typedef int (*task_finished_fn)(int result,
 210                                 struct strbuf *out,
 211                                 void *pp_cb,
 212                                 void *pp_task_cb);
 213
 214 /**
 215  * Runs up to n processes at the same time. Whenever a process can be
 216  * started, the callback get_next_task_fn is called to obtain the data
 217  * required to start another child process.
 218  *
 219  * The children started via this function run in parallel. Their output
 220  * (both stdout and stderr) is routed to stderr in a manner that output
 221  * from different tasks does not interleave.
 222  *
 223  * start_failure_fn and task_finished_fn can be NULL to omit any
 224  * special handling.
 225  */
 226 int run_processes_parallel(int n,
 227                            get_next_task_fn,
 228                            start_failure_fn,
 229                            task_finished_fn,
 230                            void *pp_cb);
 231 int run_processes_parallel_tr2(int n, get_next_task_fn, start_failure_fn,
 232                                task_finished_fn, void *pp_cb,
 233                                const char *tr2_category, const char *tr2_label);
 234
 235 #endif