builtin/for-each-repo: remove unnecessary argv copy to plug leak

cmd_for_each_repo() copies argv into args (a strvec), which is later
passed into run_command_on_repo(), which in turn copies that strvec onto
the end of child.args. The initial copy is unnecessary (we never modify
args). We therefore choose to just pass argv directly into
run_command_on_repo(), which lets us avoid the copy and fixes the leak.

LSAN output from t0068:

Direct leak of 192 byte(s) in 1 object(s) allocated from:
    #0 0x7f63bd4ab8b0 in realloc (/usr/lib64/libasan.so.4+0xdc8b0)
    #1 0x98d7e6 in xrealloc wrapper.c:126
    #2 0x916914 in strvec_push_nodup strvec.c:19
    #3 0x916a6e in strvec_push strvec.c:26
    #4 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49
    #5 0x410dcd in run_builtin git.c:475
    #6 0x410dcd in handle_builtin git.c:729
    #7 0x414087 in run_argv git.c:818
    #8 0x414087 in cmd_main git.c:949
    #9 0x40e9ec in main common-main.c:52
    #10 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349)

Indirect leak of 22 byte(s) in 2 object(s) allocated from:
    #0 0x7f63bd445e30 in __interceptor_strdup (/usr/lib64/libasan.so.4+0x76e30)
    #1 0x98d698 in xstrdup wrapper.c:29
    #2 0x916a63 in strvec_push strvec.c:26
    #3 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49
    #4 0x410dcd in run_builtin git.c:475
    #5 0x410dcd in handle_builtin git.c:729
    #6 0x414087 in run_argv git.c:818
    #7 0x414087 in cmd_main git.c:949
    #8 0x40e9ec in main common-main.c:52
    #9 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349)

See also discussion about the original implementation below - this code
appears to have evolved from a callback explaining the double-strvec-copy
pattern, but there's no strong reason to keep that now:
  https://lore.kernel.org/git/68bbeca5-314b-08ee-ef36-040e3f3814e9@gmail.com/

Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/for-each-repo.c b/builtin/for-each-repo.c
index 52be64a4373a3a4fb992662aaee54e17c9d03b46..fd86e5a8619256fd903122b08e937141eb1725f0 100644 (file)
--- a/builtin/for-each-repo.c
+++ b/builtin/for-each-repo.c
@@ -10,18 +10,16 @@ static const char * const for_each_repo_usage[] = {
        NULL
 };
 
-static int run_command_on_repo(const char *path,
-                              void *cbdata)
+static int run_command_on_repo(const char *path, int argc, const char ** argv)
 {
        int i;
        struct child_process child = CHILD_PROCESS_INIT;
-       struct strvec *args = (struct strvec *)cbdata;
 
        child.git_cmd = 1;
        strvec_pushl(&child.args, "-C", path, NULL);
 
-       for (i = 0; i < args->nr; i++)
-               strvec_push(&child.args, args->v[i]);
+       for (i = 0; i < argc; i++)
+               strvec_push(&child.args, argv[i]);
 
        return run_command(&child);
 }
@@ -31,7 +29,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
        static const char *config_key = NULL;
        int i, result = 0;
        const struct string_list *values;
-       struct strvec args = STRVEC_INIT;
 
        const struct option options[] = {
                OPT_STRING(0, "config", &config_key, N_("config"),
@@ -45,9 +42,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
        if (!config_key)
                die(_("missing --config=<config>"));
 
-       for (i = 0; i < argc; i++)
-               strvec_push(&args, argv[i]);
-
        values = repo_config_get_value_multi(the_repository,
                                             config_key);
 
@@ -59,7 +53,7 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
                return 0;
 
        for (i = 0; !result && i < values->nr; i++)
-               result = run_command_on_repo(values->items[i].string, &args);
+               result = run_command_on_repo(values->items[i].string, argc, argv);
 
        return result;
 }