[PATCH v5 4/8] tools subcmd: Add a no exec function call option

Ian Rogers
2024-02-16T23:55:22Z

Tools like perf fork tests in case they crash, but they don't want to
exec a full binary. Add an option to call a function rather than do an
exec. The child process exits with the result of the function call and
is passed the struct of the run_command, things like container_of can
then allow the child process function to determine additional
arguments.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/lib/subcmd/run-command.c | 2 ++
tools/lib/subcmd/run-command.h | 2 ++
2 files changed, 4 insertions(+)

diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c
index 5cdac2162532..d435eb42354b 100644
--- a/tools/lib/subcmd/run-command.c
+++ b/tools/lib/subcmd/run-command.c
@@ -122,6 +122,8 @@ int start_command(struct child_process *cmd)
}
if (cmd->preexec_cb)
cmd->preexec_cb();
+ if (cmd->no_exec_cmd)
+ exit(cmd->no_exec_cmd(cmd));
if (cmd->exec_cmd) {
execv_cmd(cmd->argv);
} else {
diff --git a/tools/lib/subcmd/run-command.h b/tools/lib/subcmd/run-command.h
index 17d969c6add3..d794138a797f 100644
--- a/tools/lib/subcmd/run-command.h
+++ b/tools/lib/subcmd/run-command.h
@@ -47,6 +47,8 @@ struct child_process {
unsigned exec_cmd:1; /* if this is to be external sub-command */
unsigned stdout_to_stderr:1;
void (*preexec_cb)(void);
+ /* If set, call function in child rather than doing an exec. */
+ int (*no_exec_cmd)(struct child_process *process);
};

int start_command(struct child_process *);
--
2.44.0.rc0.258.g7320e95886-goog