Re: [PATCH 0/3] Call builtin functions directly, was Re: [PATCH] transport.c: call dash-less form of receive-pack and upload-pack on remote
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Dec 2, 2007, 05:19 UTC
- Message-ID
- <7v3aul1xmt.fsf@gitster.siamese.dyndns.org>
- In-Reply-To
- <Pine.LNX.4.64.0712020146240.27959@racer.site>
Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
Show 5 quoted lines
> Okay, I bit the apple and tried to move the builtins into the library, and > rename handle_internal_command into execv_git_builtin(), moving it into > exec-cmd.c. > > Big mistake.
I really feel this should not go in. Anything called exec _should_ assure the callers that the new command will start from a clean slate, and the way to give that assurance is by actually doing exec(), not introducing "clean-up" functions for random things we can think of (like cached objects) and risking of forgetting some others. I do not think the complexity is worth it.
The first step we have decided to take is to move git-foo form out of users' PATH. This would reduce the cluttered PATH problem, and it means not all of external commands have to become built-ins on a single flag day. I also think it has always been a nice touch that we allowed users to drop their own custom git-foo script to their path and call "git foo" as if it is part of the official git suite, so spawning commands in git-foo form needs to be supported via GIT_EXEC_PATH even if everything eventually becomes built-in.
So I would prefer doing something like this instead for v1.5.5 (see the top of updated release notes for 1.5.4 for deprecation notice).
* execv_git_cmd() function will exec "git" with the given subcommand and its arguments;
* The command dispatcher of git potty itself will first try the built-ins, and then try externals in dash form (which cannot be done with execv_git_cmd() anymore), and then aliases.
* Just to be nice, we allow git-shell to treat "git foo arg" as if "git-foo arg" was given, but it continues to use execv_git_cmd(), and starts from a clean slate.
--- exec_cmd.c | 31 ++++++++++++------------------- git.c | 32 +++++++++++++++++++++++++++++++- shell.c | 26 +++++++++++++++----------- 3 files changed, 58 insertions(+), 31 deletions(-)
diff --git a/exec_cmd.c b/exec_cmd.c index 2d0a758..10b2908 100644 --- a/exec_cmd.c +++ b/exec_cmd.c @@ -65,32 +65,25 @@ void setup_path(const char *cmd_path) int execv_git_cmd(const char **argv) { - struct strbuf cmd; - const char *tmp; - - strbuf_init(&cmd, 0); - strbuf_addf(&cmd, "git-%s", argv[0]); + int argc; + const char **nargv; - /* - * argv[0] must be the git command, but the argv array - * belongs to the caller, and may be reused in - * subsequent loop iterations. Save argv[0] and - * restore it on error. - */ - tmp = argv[0]; - argv[0] = cmd.buf; + for (argc = 0; argv[argc]; argc++) + ; /* just counting */ + nargv = xmalloc(sizeof(*nargv) * (argc + 2)); - trace_argv_printf(argv, -1, "trace: exec:"); + nargv[0] = "git"; + for (argc = 0; argv[argc]; argc++) + nargv[argc + 1] = argv[argc]; + nargv[argc + 1] = NULL; + trace_argv_printf(nargv, -1, "trace: exec:"); /* execvp() can only ever return if it fails */ - execvp(cmd.buf, (char **)argv); + execvp("git", (char **)nargv); trace_printf("trace: exec failed: %s\n", strerror(errno)); - argv[0] = tmp; - - strbuf_release(&cmd); - + free(nargv); return -1; } diff --git a/git.c b/git.c index 01bbbc7..d690426 100644 --- a/git.c +++ b/git.c @@ -382,6 +382,36 @@ static void handle_internal_command(int argc, const char **argv) } } +static void execv_dashed_external(const char **argv) +{ + struct strbuf cmd; + const char *tmp; + + strbuf_init(&cmd, 0); + strbuf_addf(&cmd, "git-%s", argv[0]); + + /* + * argv[0] must be the git command, but the argv array + * belongs to the caller, and may be reused in + * subsequent loop iterations. Save argv[0] and + * restore it on error. + */ + tmp = argv[0]; + argv[0] = cmd.buf; + + trace_argv_printf(argv, -1, "trace: exec:"); + + /* execvp() can only ever return if it fails */ + execvp(cmd.buf, (char **)argv); + + trace_printf("trace: exec failed: %s\n", strerror(errno)); + + argv[0] = tmp; + + strbuf_release(&cmd); +} + + int main(int argc, const char **argv) { const char *cmd = argv[0] ? argv[0] : "git-help"; @@ -445,7 +475,7 @@ int main(int argc, const char **argv) handle_internal_command(argc, argv); /* .. then try the external ones */ - execv_git_cmd(argv); + execv_dashed_external(argv); /* It could be an alias -- this works around the insanity * of overriding "git log" with "git show" by having diff --git a/shell.c b/shell.c index 9826109..729797c 100644 --- a/shell.c +++ b/shell.c @@ -19,17 +19,13 @@ static int do_generic_cmd(const char *me, char *arg) return execv_git_cmd(my_argv); } -static int do_cvs_cmd(const char *me, char *arg) +static int do_cvs_cmd(void) { const char *cvsserver_argv[3] = { "cvsserver", "server", NULL }; - if (!arg || strcmp(arg, "server")) - die("git-cvsserver only handles server: %s", arg); - setup_path(NULL); - return execv_git_cmd(cvsserver_argv); } @@ -40,7 +36,6 @@ static struct commands { } cmd_list[] = { { "git-receive-pack", do_generic_cmd }, { "git-upload-pack", do_generic_cmd }, - { "cvs", do_cvs_cmd }, { NULL }, }; @@ -49,15 +44,24 @@ int main(int argc, char **argv) char *prog; struct commands *cmd; + /* + * Special hack to pretend to be a CVS server + */ if (argc == 2 && !strcmp(argv[1], "cvs server")) - argv--; - /* We want to see "-c cmd args", and nothing else */ - else if (argc != 3 || strcmp(argv[1], "-c")) + exit(do_cvs_cmd()); + + /* + * We do not accept anything but "-c" followed by "cmd arg", + * where "cmd" is a very limited subset of git commands. + */ + if (argc != 3 || strcmp(argv[1], "-c")) die("What do you think I am? A shell?"); prog = argv[2]; - argv += 2; - argc -= 2; + if (!strncmp(prog, "git", 3) && isspace(prog[3])) + /* Accept "git foo" as if the caller said "git-foo". */ + prog[3] = '-'; + for (cmd = cmd_list ; cmd->name ; cmd++) { int len = strlen(cmd->name); char *arg;