diff options
Diffstat (limited to 'run-command.h')
| -rw-r--r-- | run-command.h | 153 |
1 files changed, 110 insertions, 43 deletions
diff --git a/run-command.h b/run-command.h index af1296769f..2be5f5d642 100644 --- a/run-command.h +++ b/run-command.h @@ -44,22 +44,35 @@ struct child_process { /** - * The .argv member is set up as an array of string pointers (NULL - * terminated), of which .argv[0] is the program name to run (usually - * without a path). If the command to run is a git command, set argv[0] to - * the command name without the 'git-' prefix and set .git_cmd = 1. + * The .args is a `struct strvec', use that API to manipulate + * it, e.g. strvec_pushv() to add an existing "const char **" + * vector. * - * Note that the ownership of the memory pointed to by .argv stays with the - * caller, but it should survive until `finish_command` completes. If the - * .argv member is NULL, `start_command` will point it at the .args - * `strvec` (so you may use one or the other, but you must use exactly - * one). The memory in .args will be cleaned up automatically during - * `finish_command` (or during `start_command` when it is unsuccessful). + * If the command to run is a git command, set the first + * element in the strvec to the command name without the + * 'git-' prefix and set .git_cmd = 1. * + * The memory in .args will be cleaned up automatically during + * `finish_command` (or during `start_command` when it is unsuccessful). */ - const char **argv; - struct strvec args; + + /** + * Like .args the .env_array is a `struct strvec'. + * + * To modify the environment of the sub-process, specify an array of + * environment settings. Each string in the array manipulates the + * environment. + * + * - If the string is of the form "VAR=value", i.e. it contains '=' + * the variable is added to the child process's environment. + * + * - If the string does not contain '=', it names an environment + * variable that will be removed from the child process's environment. + * + * The memory in .env_array will be cleaned up automatically during + * `finish_command` (or during `start_command` when it is unsuccessful). + */ struct strvec env_array; pid_t pid; @@ -96,23 +109,6 @@ struct child_process { */ const char *dir; - /** - * To modify the environment of the sub-process, specify an array of - * string pointers (NULL terminated) in .env: - * - * - If the string is of the form "VAR=value", i.e. it contains '=' - * the variable is added to the child process's environment. - * - * - If the string does not contain '=', it names an environment - * variable that will be removed from the child process's environment. - * - * If the .env member is NULL, `start_command` will point it at the - * .env_array `strvec` (so you may use one or the other, but not both). - * The memory in .env_array will be cleaned up automatically during - * `finish_command` (or during `start_command` when it is unsuccessful). - */ - const char *const *env; - unsigned no_stdin:1; unsigned no_stdout:1; unsigned no_stderr:1; @@ -134,6 +130,14 @@ struct child_process { */ unsigned use_shell:1; + /** + * Release any open file handles to the object store before running + * the command; This is necessary e.g. when the spawned process may + * want to repack because that would delete `.pack` files (and on + * Windows, you cannot delete files that are still in use). + */ + unsigned close_object_store:1; + unsigned stdout_to_stderr:1; unsigned clean_on_exit:1; unsigned wait_after_clean:1; @@ -183,6 +187,18 @@ void child_process_clear(struct child_process *); int is_executable(const char *name); /** + * Check if the command exists on $PATH. This emulates the path search that + * execvp would perform, without actually executing the command so it + * can be used before fork() to prepare to run a command using + * execve() or after execvp() to diagnose why it failed. + * + * The caller should ensure that command contains no directory separators. + * + * Returns 1 if it is found in $PATH or 0 if the command could not be found. + */ +int exists_in_PATH(const char *command); + +/** * Start a sub-process. Takes a pointer to a `struct child_process` * that specifies the details and returns pipe FDs (if requested). * See below for details. @@ -204,13 +220,6 @@ int finish_command_in_signal(struct child_process *); */ int run_command(struct child_process *); -/* - * Returns the path to the hook file, or NULL if the hook is missing - * or disabled. Note that this points to static storage that will be - * overwritten by further calls to find_hook and run_hook_*. - */ -const char *find_hook(const char *name); - /** * Run a hook. * The first argument is a pathname to an index file, or NULL @@ -233,13 +242,14 @@ int run_hook_ve(const char *const *env, const char *name, va_list args); */ int run_auto_maintenance(int quiet); -#define RUN_COMMAND_NO_STDIN 1 -#define RUN_GIT_CMD 2 /*If this is to be git sub-command */ -#define RUN_COMMAND_STDOUT_TO_STDERR 4 -#define RUN_SILENT_EXEC_FAILURE 8 -#define RUN_USING_SHELL 16 -#define RUN_CLEAN_ON_EXIT 32 -#define RUN_WAIT_AFTER_CLEAN 64 +#define RUN_COMMAND_NO_STDIN (1<<0) +#define RUN_GIT_CMD (1<<1) +#define RUN_COMMAND_STDOUT_TO_STDERR (1<<2) +#define RUN_SILENT_EXEC_FAILURE (1<<3) +#define RUN_USING_SHELL (1<<4) +#define RUN_CLEAN_ON_EXIT (1<<5) +#define RUN_WAIT_AFTER_CLEAN (1<<6) +#define RUN_CLOSE_OBJECT_STORE (1<<7) /** * Convenience functions that encapsulate a sequence of @@ -496,4 +506,61 @@ int run_processes_parallel_tr2(int n, get_next_task_fn, start_failure_fn, */ void prepare_other_repo_env(struct strvec *env_array, const char *new_git_dir); +/** + * Possible return values for start_bg_command(). + */ +enum start_bg_result { + /* child process is "ready" */ + SBGR_READY = 0, + + /* child process could not be started */ + SBGR_ERROR, + + /* callback error when testing for "ready" */ + SBGR_CB_ERROR, + + /* timeout expired waiting for child to become "ready" */ + SBGR_TIMEOUT, + + /* child process exited or was signalled before becomming "ready" */ + SBGR_DIED, +}; + +/** + * Callback used by start_bg_command() to ask whether the + * child process is ready or needs more time to become "ready". + * + * The callback will receive the cmd and cb_data arguments given to + * start_bg_command(). + * + * Returns 1 is child needs more time (subject to the requested timeout). + * Returns 0 if child is "ready". + * Returns -1 on any error and cause start_bg_command() to also error out. + */ +typedef int(start_bg_wait_cb)(const struct child_process *cmd, void *cb_data); + +/** + * Start a command in the background. Wait long enough for the child + * to become "ready" (as defined by the provided callback). Capture + * immediate errors (like failure to start) and any immediate exit + * status (such as a shutdown/signal before the child became "ready") + * and return this like start_command(). + * + * We run a custom wait loop using the provided callback to wait for + * the child to start and become "ready". This is limited by the given + * timeout value. + * + * If the child does successfully start and become "ready", we orphan + * it into the background. + * + * The caller must not call finish_command(). + * + * The opaque cb_data argument will be forwarded to the callback for + * any instance data that it might require. This may be NULL. + */ +enum start_bg_result start_bg_command(struct child_process *cmd, + start_bg_wait_cb *wait_cb, + void *cb_data, + unsigned int timeout_sec); + #endif |