[PATCH] run-command: do not pass child process data into callbacks
- From
Stefan Beller <sbeller@google.com>
- Date
- Feb 29, 2016, 21:57 UTC
- Message-ID
- <1456783026-3328-1-git-send-email-sbeller@google.com>
The expected way to pass data into the callback is to pass them via the customizable callback pointer. The error reporting in default_{start_failure, task_finished} is not user friendly enough, that we want to encourage using the child data for such purposes.
Furthermore the struct child data is cleaned by the run-command API, before we access them in the callbacks, leading to use-after-free situations.
Signed-off-by: Stefan Beller <sbeller@google.com> ---
This is the proper fix to not access memory after freeing.
run-command.c | 24 +++--------------------- run-command.h | 4 +--- submodule.c | 7 +++---- test-run-command.c | 1 - 4 files changed, 7 insertions(+), 29 deletions(-)
diff --git a/run-command.c b/run-command.c index 863dad5..c726010 100644 --- a/run-command.c +++ b/run-command.c @@ -902,35 +902,18 @@ struct parallel_processes { struct strbuf buffered_output; /* of finished children */ }; -static int default_start_failure(struct child_process *cp, - struct strbuf *err, +static int default_start_failure(struct strbuf *err, void *pp_cb, void *pp_task_cb) { - int i; - - strbuf_addstr(err, "Starting a child failed:"); - for (i = 0; cp->argv[i]; i++) - strbuf_addf(err, " %s", cp->argv[i]); - return 0; } static int default_task_finished(int result, - struct child_process *cp, struct strbuf *err, void *pp_cb, void *pp_task_cb) { - int i; - - if (!result) - return 0; - - strbuf_addf(err, "A child failed with return code %d:", result); - for (i = 0; cp->argv[i]; i++) - strbuf_addf(err, " %s", cp->argv[i]); - return 0; } @@ -1048,8 +1031,7 @@ static int pp_start_one(struct parallel_processes *pp) pp->children[i].process.no_stdin = 1; if (start_command(&pp->children[i].process)) { - code = pp->start_failure(&pp->children[i].process, - &pp->children[i].err, + code = pp->start_failure(&pp->children[i].err, pp->data, &pp->children[i].data); strbuf_addbuf(&pp->buffered_output, &pp->children[i].err); @@ -1117,7 +1099,7 @@ static int pp_collect_finished(struct parallel_processes *pp) code = finish_command(&pp->children[i].process); - code = pp->task_finished(code, &pp->children[i].process, + code = pp->task_finished(code, &pp->children[i].err, pp->data, &pp->children[i].data); diff --git a/run-command.h b/run-command.h index 42917e8..c6a3e42 100644 --- a/run-command.h +++ b/run-command.h @@ -159,8 +159,7 @@ typedef int (*get_next_task_fn)(struct child_process *cp, * To send a signal to other child processes for abortion, return * the negative signal number. */ -typedef int (*start_failure_fn)(struct child_process *cp, - struct strbuf *err, +typedef int (*start_failure_fn)(struct strbuf *err, void *pp_cb, void *pp_task_cb); @@ -179,7 +178,6 @@ typedef int (*start_failure_fn)(struct child_process *cp, * the negative signal number. */ typedef int (*task_finished_fn)(int result, - struct child_process *cp, struct strbuf *err, void *pp_cb, void *pp_task_cb); diff --git a/submodule.c b/submodule.c index 24fb81a..62c4356 100644 --- a/submodule.c +++ b/submodule.c @@ -705,8 +705,7 @@ static int get_next_submodule(struct child_process *cp, return 0; } -static int fetch_start_failure(struct child_process *cp, - struct strbuf *err, +static int fetch_start_failure(struct strbuf *err, void *cb, void *task_cb) { struct submodule_parallel_fetch *spf = cb; @@ -716,8 +715,8 @@ static int fetch_start_failure(struct child_process *cp, return 0; } -static int fetch_finish(int retvalue, struct child_process *cp, - struct strbuf *err, void *cb, void *task_cb) +static int fetch_finish(int retvalue, struct strbuf *err, + void *cb, void *task_cb) { struct submodule_parallel_fetch *spf = cb; diff --git a/test-run-command.c b/test-run-command.c index fbe0a27..30a64a9 100644 --- a/test-run-command.c +++ b/test-run-command.c @@ -41,7 +41,6 @@ static int no_job(struct child_process *cp, } static int task_finished(int result, - struct child_process *cp, struct strbuf *err, void *pp_cb, void *pp_task_cb)
-- 2.8.0.rc0.1.g68b4e3f