diff options
authorJeff King <>2014-05-15 08:33:26 (GMT)
committerJunio C Hamano <>2014-05-15 16:49:09 (GMT)
commitc460c0ecdca46be85f6d9c845f9df7ce0e45c3c2 (patch)
parent6308767f0bb58116cb405e1f4f77f5dfc1589920 (diff)
run-command: store an optional argv_array
All child_process structs need to point to an argv. For flexibility, we do not mandate the use of a dynamic argv_array. However, because the child_process does not own the memory, this can make memory management with a separate argv_array difficult. For example, if a function calls start_command but not finish_command, the argv memory must persist. The code needs to arrange to clean up the argv_array separately after finish_command runs. As a result, some of our code in this situation just leaks the memory. To help such cases, this patch adds a built-in argv_array to the child_process, which gets cleaned up automatically (both in finish_command and when start_command fails). Callers may use it if they choose, but can continue to use the raw argv if they wish. Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
3 files changed, 18 insertions, 1 deletions
diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt
index 5d7d7f2..69510ae 100644
--- a/Documentation/technical/api-run-command.txt
+++ b/Documentation/technical/api-run-command.txt
@@ -109,6 +109,13 @@ 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.
+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
+`argv_array` (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).
The members .in, .out, .err are used to redirect stdin, stdout,
stderr as follows:
diff --git a/run-command.c b/run-command.c
index 75abc47..be07d4a 100644
--- a/run-command.c
+++ b/run-command.c
@@ -279,6 +279,9 @@ int start_command(struct child_process *cmd)
int failed_errno;
char *str;
+ if (!cmd->argv)
+ cmd->argv = cmd->args.argv;
* In case of errors we must keep the promise to close FDs
* that have been passed in via ->in and ->out.
@@ -328,6 +331,7 @@ int start_command(struct child_process *cmd)
error("cannot create %s pipe for %s: %s",
str, cmd->argv[0], strerror(failed_errno));
+ argv_array_clear(&cmd->args);
errno = failed_errno;
return -1;
@@ -519,6 +523,7 @@ fail_pipe:
else if (cmd->err)
+ argv_array_clear(&cmd->args);
errno = failed_errno;
return -1;
@@ -543,7 +548,9 @@ fail_pipe:
int finish_command(struct child_process *cmd)
- return wait_or_whine(cmd->pid, cmd->argv[0]);
+ int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
+ argv_array_clear(&cmd->args);
+ return ret;
int run_command(struct child_process *cmd)
diff --git a/run-command.h b/run-command.h
index 3653bfa..ea73de3 100644
--- a/run-command.h
+++ b/run-command.h
@@ -5,8 +5,11 @@
#include <pthread.h>
+#include "argv-array.h"
struct child_process {
const char **argv;
+ struct argv_array args;
pid_t pid;
* Using .in, .out, .err: