Re: [PATCH] alias: detect loops in mixed execution mode
From: Ævar Arnfjörð Bjarmason <hidden>
Date: 2018-10-19 08:28:29
On Thu, Oct 18 2018, Ævar Arnfjörð Bjarmason wrote:
quoted hunk ↗ jump to hunk
+static void init_cmd_history(struct strbuf *env, struct string_list *cmd_list) +{ + const char *old = getenv(COMMAND_HISTORY_ENVIRONMENT); + struct strbuf **cmd_history, **ptr; + + if (!old || !*old) + return; + + strbuf_addstr(env, old); + strbuf_rtrim(env); + + cmd_history = strbuf_split_buf(old, strlen(old), ' ', 0); + for (ptr = cmd_history; *ptr; ptr++) { + strbuf_rtrim(*ptr); + string_list_append(cmd_list, (*ptr)->buf); + } + strbuf_list_free(cmd_history); +} + +static void add_cmd_history(struct strbuf *env, struct string_list *cmd_list, + const char *cmd) +{ + string_list_append(cmd_list, cmd); + if (env->len) + strbuf_addch(env, ' '); + strbuf_addstr(env, cmd); + setenv(COMMAND_HISTORY_ENVIRONMENT, env->buf, 1); +} + static int run_argv(int *argcp, const char ***argv) { int done_alias = 0; - struct string_list cmd_list = STRING_LIST_INIT_NODUP; + struct string_list cmd_list = STRING_LIST_INIT_DUP; struct string_list_item *seen; + struct strbuf env = STRBUF_INIT; + init_cmd_history(&env, &cmd_list); while (1) { /* * If we tried alias and futzed with our environment,@@ -711,7 +742,7 @@ static int run_argv(int *argcp, const char ***argv) " not terminate:%s"), cmd_list.items[0].string, sb.buf); } - string_list_append(&cmd_list, *argv[0]); + add_cmd_history(&env, &cmd_list, *argv[0]); /* * It could be an alias -- this works around the insanity
Just to sanity check an assumption of mine: One thing I didn't do is use
sq_quote_buf() and sq_dequote_to_argv() like we do for
CONFIG_DATA_ENVIRONMENT. This is because in the case of config we need
to deal with:
$ git config alias.cfgdump
!env
$ git -c x.y=z -c "foo.bar='baz'" cfgdump|grep baz
GIT_CONFIG_PARAMETERS='x.y=z' 'foo.bar='\''baz'\'''
But in this case I don't see how a command-name would ever contain
whitespace. So we skip quoting and just delimit by space.
There's also nothing stopping you from doing e.g.:
$ GIT_COMMAND_HISTORY='foo bar' ~/g/git/git --exec-path=$PWD one
fatal: alias loop detected: expansion of 'foo' does not terminate:
foo
bar
one
two <==
three
four
five ==>
Or even confuse the code by adding a whitespace at the beginning:
$ GIT_COMMAND_HISTORY=' foo bar' ~/g/git/git --exec-path=$PWD one
fatal: alias loop detected: expansion of '' does not terminate:
foo
bar
one
two <==
three
four
five ==>
I thought none of this was worth dealing with. Worst case someone's
screwing with this, but I don't see how it would happen accidentally,
and even then we detect the infinite loop and just degrade to confusing
error messages because you decided to screw with git's GIT_* env vars.