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@xxxxxxxxxx>
---
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
--
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