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git/git.c
Jeff King 46df6906f3 execv_dashed_external: wait for child on signal death 
When you hit ^C to interrupt a git command going to a pager,
this usually leaves the pager running. But when a dashed
external is in use, the pager ends up in a funny state and
quits (but only after eating one more character from the
terminal!). This fixes it.

Explaining the reason will require a little background.

When git runs a pager, it's important for the git process to
hang around and wait for the pager to finish, even though it
has no more data to feed it. This is because git spawns the
pager as a child, and thus the git process is the session
leader on the terminal. After it dies, the pager will finish
its current read from the terminal (eating the one
character), and then get EIO trying to read again.

When you hit ^C, that sends SIGINT to git and to the pager,
and it's a similar situation.  The pager ignores it, but the
git process needs to hang around until the pager is done. We
addressed that long ago in a3da882120 (pager: do
wait_for_pager on signal death, 2009-01-22).

But when you have a dashed external (or an alias pointing to
a builtin, which will re-exec git for the builtin), there's
an extra process in the mix. For instance, running:

  $ git -c alias.l=log l

will end up with a process tree like:

  git (parent)
    \
     git-log (child)
      \
       less (pager)

If you hit ^C, SIGINT goes to all of them. The pager ignores
it, and the child git process will end up in wait_for_pager().
But the parent git process will die, and the usual EIO
trouble happens.

So we really want the parent git process to wait_for_pager(),
but of course it doesn't know anything about the pager at
all, since it was started by the child.  However, we can
have it wait on the git-log child, which in turn is waiting
on the pager. And that's what this patch does.

There are a few design decisions here worth explaining:

  1. The new feature is attached to run-command's
     clean_on_exit feature. Partly this is convenience,
     since that feature already has a signal handler that
     deals with child cleanup.

     But it's also a meaningful connection. The main reason
     that dashed externals use clean_on_exit is to bind the
     two processes together. If somebody kills the parent
     with a signal, we propagate that to the child (in this
     instance with SIGINT, we do propagate but it doesn't
     matter because the original signal went to the whole
     process group). Likewise, we do not want the parent
     to go away until the child has done so.

     In a traditional Unix world, we'd probably accomplish
     this binding by just having the parent execve() the
     child directly. But since that doesn't work on Windows,
     everything goes through run_command's more spawn-like
     interface.

  2. We do _not_ automatically waitpid() on any
     clean_on_exit children. For dashed externals this makes
     sense; we know that the parent is doing nothing but
     waiting for the child to exit anyway. But with other
     children, it's possible that the child, after getting
     the signal, could be waiting on the parent to do
     something (like closing a descriptor). If we were to
     wait on such a child, we'd end up in a deadlock. So
     this errs on the side of caution, and lets callers
     enable the feature explicitly.

  3. When we send children the cleanup signal, we send all
     the signals first, before waiting on any children. This
     is to avoid the case where one child might be waiting
     on another one to exit, causing a deadlock. We inform
     all of them that it's time to die before reaping any.

     In practice, there is only ever one dashed external run
     from a given process, so this doesn't matter much now.
     But it future-proofs us if other callers start using
     the wait_after_clean mechanism.

There's no automated test here, because it would end up racy
and unportable. But it's easy to reproduce the situation by
running the log command given above and hitting ^C.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-09 13:41:40 -08:00

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#include "builtin.h"
#include "exec_cmd.h"
#include "help.h"
#include "run-command.h"
const char git_usage_string[] =
"git [--version] [--help] [-C <path>] [-c name=value]\n"
" [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
" [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]\n"
" [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
" <command> [<args>]";
const char git_more_info_string[] =
N_("'git help -a' and 'git help -g' list available subcommands and some\n"
"concept guides. See 'git help <command>' or 'git help <concept>'\n"
"to read about a specific subcommand or concept.");
static int use_pager = -1;
static char *orig_cwd;
static const char *env_names[] = {
GIT_DIR_ENVIRONMENT,
GIT_WORK_TREE_ENVIRONMENT,
GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
GIT_PREFIX_ENVIRONMENT
};
static char *orig_env[4];
static int save_restore_env_balance;
static void save_env_before_alias(void)
{
int i;
assert(save_restore_env_balance == 0);
save_restore_env_balance = 1;
orig_cwd = xgetcwd();
for (i = 0; i < ARRAY_SIZE(env_names); i++) {
orig_env[i] = getenv(env_names[i]);
orig_env[i] = xstrdup_or_null(orig_env[i]);
}
}
static void restore_env(int external_alias)
{
int i;
assert(save_restore_env_balance == 1);
save_restore_env_balance = 0;
if (!external_alias && orig_cwd && chdir(orig_cwd))
die_errno("could not move to %s", orig_cwd);
free(orig_cwd);
for (i = 0; i < ARRAY_SIZE(env_names); i++) {
if (external_alias &&
!strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
continue;
if (orig_env[i]) {
setenv(env_names[i], orig_env[i], 1);
free(orig_env[i]);
} else {
unsetenv(env_names[i]);
}
}
}
static void commit_pager_choice(void) {
switch (use_pager) {
case 0:
setenv("GIT_PAGER", "cat", 1);
break;
case 1:
setup_pager();
break;
default:
break;
}
}
static int handle_options(const char ***argv, int *argc, int *envchanged)
{
const char **orig_argv = *argv;
while (*argc > 0) {
const char *cmd = (*argv)[0];
if (cmd[0] != '-')
break;
/*
* For legacy reasons, the "version" and "help"
* commands can be written with "--" prepended
* to make them look like flags.
*/
if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
break;
/*
* Check remaining flags.
*/
if (skip_prefix(cmd, "--exec-path", &cmd)) {
if (*cmd == '=')
git_set_argv_exec_path(cmd + 1);
else {
puts(git_exec_path());
exit(0);
}
} else if (!strcmp(cmd, "--html-path")) {
puts(system_path(GIT_HTML_PATH));
exit(0);
} else if (!strcmp(cmd, "--man-path")) {
puts(system_path(GIT_MAN_PATH));
exit(0);
} else if (!strcmp(cmd, "--info-path")) {
puts(system_path(GIT_INFO_PATH));
exit(0);
} else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
use_pager = 1;
} else if (!strcmp(cmd, "--no-pager")) {
use_pager = 0;
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--no-replace-objects")) {
check_replace_refs = 0;
setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--git-dir")) {
if (*argc < 2) {
fprintf(stderr, "No directory given for --git-dir.\n" );
usage(git_usage_string);
}
setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
if (envchanged)
*envchanged = 1;
(*argv)++;
(*argc)--;
} else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--namespace")) {
if (*argc < 2) {
fprintf(stderr, "No namespace given for --namespace.\n" );
usage(git_usage_string);
}
setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
if (envchanged)
*envchanged = 1;
(*argv)++;
(*argc)--;
} else if (skip_prefix(cmd, "--namespace=", &cmd)) {
setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--work-tree")) {
if (*argc < 2) {
fprintf(stderr, "No directory given for --work-tree.\n" );
usage(git_usage_string);
}
setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
if (envchanged)
*envchanged = 1;
(*argv)++;
(*argc)--;
} else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--super-prefix")) {
if (*argc < 2) {
fprintf(stderr, "No prefix given for --super-prefix.\n" );
usage(git_usage_string);
}
setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
if (envchanged)
*envchanged = 1;
(*argv)++;
(*argc)--;
} else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--bare")) {
char *cwd = xgetcwd();
is_bare_repository_cfg = 1;
setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
free(cwd);
setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "-c")) {
if (*argc < 2) {
fprintf(stderr, "-c expects a configuration string\n" );
usage(git_usage_string);
}
git_config_push_parameter((*argv)[1]);
(*argv)++;
(*argc)--;
} else if (!strcmp(cmd, "--literal-pathspecs")) {
setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--no-literal-pathspecs")) {
setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--glob-pathspecs")) {
setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--noglob-pathspecs")) {
setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--icase-pathspecs")) {
setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "--shallow-file")) {
(*argv)++;
(*argc)--;
set_alternate_shallow_file((*argv)[0], 1);
if (envchanged)
*envchanged = 1;
} else if (!strcmp(cmd, "-C")) {
if (*argc < 2) {
fprintf(stderr, "No directory given for -C.\n" );
usage(git_usage_string);
}
if ((*argv)[1][0]) {
if (chdir((*argv)[1]))
die_errno("Cannot change to '%s'", (*argv)[1]);
if (envchanged)
*envchanged = 1;
}
(*argv)++;
(*argc)--;
} else {
fprintf(stderr, "Unknown option: %s\n", cmd);
usage(git_usage_string);
}
(*argv)++;
(*argc)--;
}
return (*argv) - orig_argv;
}
static int handle_alias(int *argcp, const char ***argv)
{
int envchanged = 0, ret = 0, saved_errno = errno;
int count, option_count;
const char **new_argv;
const char *alias_command;
char *alias_string;
int unused_nongit;
save_env_before_alias();
setup_git_directory_gently(&unused_nongit);
alias_command = (*argv)[0];
alias_string = alias_lookup(alias_command);
if (alias_string) {
if (alias_string[0] == '!') {
struct child_process child = CHILD_PROCESS_INIT;
commit_pager_choice();
restore_env(1);
child.use_shell = 1;
argv_array_push(&child.args, alias_string + 1);
argv_array_pushv(&child.args, (*argv) + 1);
ret = run_command(&child);
if (ret >= 0) /* normal exit */
exit(ret);
die_errno("While expanding alias '%s': '%s'",
alias_command, alias_string + 1);
}
count = split_cmdline(alias_string, &new_argv);
if (count < 0)
die("Bad alias.%s string: %s", alias_command,
split_cmdline_strerror(count));
option_count = handle_options(&new_argv, &count, &envchanged);
if (envchanged)
die("alias '%s' changes environment variables\n"
"You can use '!git' in the alias to do this.",
alias_command);
memmove(new_argv - option_count, new_argv,
count * sizeof(char *));
new_argv -= option_count;
if (count < 1)
die("empty alias for %s", alias_command);
if (!strcmp(alias_command, new_argv[0]))
die("recursive alias: %s", alias_command);
trace_argv_printf(new_argv,
"trace: alias expansion: %s =>",
alias_command);
REALLOC_ARRAY(new_argv, count + *argcp);
/* insert after command name */
memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
*argv = new_argv;
*argcp += count - 1;
ret = 1;
}
restore_env(0);
errno = saved_errno;
return ret;
}
#define RUN_SETUP (1<<0)
#define RUN_SETUP_GENTLY (1<<1)
#define USE_PAGER (1<<2)
/*
* require working tree to be present -- anything uses this needs
* RUN_SETUP for reading from the configuration file.
*/
#define NEED_WORK_TREE (1<<3)
#define SUPPORT_SUPER_PREFIX (1<<4)
struct cmd_struct {
const char *cmd;
int (*fn)(int, const char **, const char *);
int option;
};
static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
int status, help;
struct stat st;
const char *prefix;
prefix = NULL;
help = argc == 2 && !strcmp(argv[1], "-h");
if (!help) {
if (p->option & RUN_SETUP)
prefix = setup_git_directory();
else if (p->option & RUN_SETUP_GENTLY) {
int nongit_ok;
prefix = setup_git_directory_gently(&nongit_ok);
}
if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
use_pager = check_pager_config(p->cmd);
if (use_pager == -1 && p->option & USE_PAGER)
use_pager = 1;
if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
trace_repo_setup(prefix);
}
commit_pager_choice();
if (!help && get_super_prefix()) {
if (!(p->option & SUPPORT_SUPER_PREFIX))
die("%s doesn't support --super-prefix", p->cmd);
if (prefix)
die("can't use --super-prefix from a subdirectory");
}
if (!help && p->option & NEED_WORK_TREE)
setup_work_tree();
trace_argv_printf(argv, "trace: built-in: git");
status = p->fn(argc, argv, prefix);
if (status)
return status;
/* Somebody closed stdout? */
if (fstat(fileno(stdout), &st))
return 0;
/* Ignore write errors for pipes and sockets.. */
if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
return 0;
/* Check for ENOSPC and EIO errors.. */
if (fflush(stdout))
die_errno("write failure on standard output");
if (ferror(stdout))
die("unknown write failure on standard output");
if (fclose(stdout))
die_errno("close failed on standard output");
return 0;
}
static struct cmd_struct commands[] = {
{ "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
{ "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
{ "annotate", cmd_annotate, RUN_SETUP },
{ "apply", cmd_apply, RUN_SETUP_GENTLY },
{ "archive", cmd_archive, RUN_SETUP_GENTLY },
{ "bisect--helper", cmd_bisect__helper, RUN_SETUP },
{ "blame", cmd_blame, RUN_SETUP },
{ "branch", cmd_branch, RUN_SETUP },
{ "bundle", cmd_bundle, RUN_SETUP_GENTLY },
{ "cat-file", cmd_cat_file, RUN_SETUP },
{ "check-attr", cmd_check_attr, RUN_SETUP },
{ "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
{ "check-mailmap", cmd_check_mailmap, RUN_SETUP },
{ "check-ref-format", cmd_check_ref_format },
{ "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
{ "checkout-index", cmd_checkout_index,
RUN_SETUP | NEED_WORK_TREE},
{ "cherry", cmd_cherry, RUN_SETUP },
{ "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
{ "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
{ "clone", cmd_clone },
{ "column", cmd_column, RUN_SETUP_GENTLY },
{ "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
{ "commit-tree", cmd_commit_tree, RUN_SETUP },
{ "config", cmd_config, RUN_SETUP_GENTLY },
{ "count-objects", cmd_count_objects, RUN_SETUP },
{ "credential", cmd_credential, RUN_SETUP_GENTLY },
{ "describe", cmd_describe, RUN_SETUP },
{ "diff", cmd_diff },
{ "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
{ "diff-index", cmd_diff_index, RUN_SETUP },
{ "diff-tree", cmd_diff_tree, RUN_SETUP },
{ "fast-export", cmd_fast_export, RUN_SETUP },
{ "fetch", cmd_fetch, RUN_SETUP },
{ "fetch-pack", cmd_fetch_pack, RUN_SETUP },
{ "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
{ "for-each-ref", cmd_for_each_ref, RUN_SETUP },
{ "format-patch", cmd_format_patch, RUN_SETUP },
{ "fsck", cmd_fsck, RUN_SETUP },
{ "fsck-objects", cmd_fsck, RUN_SETUP },
{ "gc", cmd_gc, RUN_SETUP },
{ "get-tar-commit-id", cmd_get_tar_commit_id },
{ "grep", cmd_grep, RUN_SETUP_GENTLY },
{ "hash-object", cmd_hash_object },
{ "help", cmd_help },
{ "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
{ "init", cmd_init_db },
{ "init-db", cmd_init_db },
{ "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
{ "log", cmd_log, RUN_SETUP },
{ "ls-files", cmd_ls_files, RUN_SETUP | SUPPORT_SUPER_PREFIX },
{ "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
{ "ls-tree", cmd_ls_tree, RUN_SETUP },
{ "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
{ "mailsplit", cmd_mailsplit },
{ "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
{ "merge-base", cmd_merge_base, RUN_SETUP },
{ "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
{ "merge-index", cmd_merge_index, RUN_SETUP },
{ "merge-ours", cmd_merge_ours, RUN_SETUP },
{ "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
{ "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
{ "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
{ "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
{ "merge-tree", cmd_merge_tree, RUN_SETUP },
{ "mktag", cmd_mktag, RUN_SETUP },
{ "mktree", cmd_mktree, RUN_SETUP },
{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
{ "name-rev", cmd_name_rev, RUN_SETUP },
{ "notes", cmd_notes, RUN_SETUP },
{ "pack-objects", cmd_pack_objects, RUN_SETUP },
{ "pack-redundant", cmd_pack_redundant, RUN_SETUP },
{ "pack-refs", cmd_pack_refs, RUN_SETUP },
{ "patch-id", cmd_patch_id, RUN_SETUP_GENTLY },
{ "pickaxe", cmd_blame, RUN_SETUP },
{ "prune", cmd_prune, RUN_SETUP },
{ "prune-packed", cmd_prune_packed, RUN_SETUP },
{ "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
{ "push", cmd_push, RUN_SETUP },
{ "read-tree", cmd_read_tree, RUN_SETUP },
{ "receive-pack", cmd_receive_pack },
{ "reflog", cmd_reflog, RUN_SETUP },
{ "remote", cmd_remote, RUN_SETUP },
{ "remote-ext", cmd_remote_ext },
{ "remote-fd", cmd_remote_fd },
{ "repack", cmd_repack, RUN_SETUP },
{ "replace", cmd_replace, RUN_SETUP },
{ "rerere", cmd_rerere, RUN_SETUP },
{ "reset", cmd_reset, RUN_SETUP },
{ "rev-list", cmd_rev_list, RUN_SETUP },
{ "rev-parse", cmd_rev_parse },
{ "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
{ "rm", cmd_rm, RUN_SETUP },
{ "send-pack", cmd_send_pack, RUN_SETUP },
{ "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
{ "show", cmd_show, RUN_SETUP },
{ "show-branch", cmd_show_branch, RUN_SETUP },
{ "show-ref", cmd_show_ref, RUN_SETUP },
{ "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
{ "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
{ "stripspace", cmd_stripspace },
{ "submodule--helper", cmd_submodule__helper, RUN_SETUP },
{ "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
{ "tag", cmd_tag, RUN_SETUP },
{ "unpack-file", cmd_unpack_file, RUN_SETUP },
{ "unpack-objects", cmd_unpack_objects, RUN_SETUP },
{ "update-index", cmd_update_index, RUN_SETUP },
{ "update-ref", cmd_update_ref, RUN_SETUP },
{ "update-server-info", cmd_update_server_info, RUN_SETUP },
{ "upload-archive", cmd_upload_archive },
{ "upload-archive--writer", cmd_upload_archive_writer },
{ "var", cmd_var, RUN_SETUP_GENTLY },
{ "verify-commit", cmd_verify_commit, RUN_SETUP },
{ "verify-pack", cmd_verify_pack },
{ "verify-tag", cmd_verify_tag, RUN_SETUP },
{ "version", cmd_version },
{ "whatchanged", cmd_whatchanged, RUN_SETUP },
{ "worktree", cmd_worktree, RUN_SETUP },
{ "write-tree", cmd_write_tree, RUN_SETUP },
};
static struct cmd_struct *get_builtin(const char *s)
{
int i;
for (i = 0; i < ARRAY_SIZE(commands); i++) {
struct cmd_struct *p = commands + i;
if (!strcmp(s, p->cmd))
return p;
}
return NULL;
}
int is_builtin(const char *s)
{
return !!get_builtin(s);
}
#ifdef STRIP_EXTENSION
static void strip_extension(const char **argv)
{
size_t len;
if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
argv[0] = xmemdupz(argv[0], len);
}
#else
#define strip_extension(cmd)
#endif
static void handle_builtin(int argc, const char **argv)
{
struct argv_array args = ARGV_ARRAY_INIT;
const char *cmd;
struct cmd_struct *builtin;
strip_extension(argv);
cmd = argv[0];
/* Turn "git cmd --help" into "git help --exclude-guides cmd" */
if (argc > 1 && !strcmp(argv[1], "--help")) {
int i;
argv[1] = argv[0];
argv[0] = cmd = "help";
for (i = 0; i < argc; i++) {
argv_array_push(&args, argv[i]);
if (!i)
argv_array_push(&args, "--exclude-guides");
}
argc++;
argv = args.argv;
}
builtin = get_builtin(cmd);
if (builtin)
exit(run_builtin(builtin, argc, argv));
argv_array_clear(&args);
}
static void execv_dashed_external(const char **argv)
{
struct child_process cmd = CHILD_PROCESS_INIT;
int status;
if (get_super_prefix())
die("%s doesn't support --super-prefix", argv[0]);
if (use_pager == -1)
use_pager = check_pager_config(argv[0]);
commit_pager_choice();
argv_array_pushf(&cmd.args, "git-%s", argv[0]);
argv_array_pushv(&cmd.args, argv + 1);
cmd.clean_on_exit = 1;
cmd.wait_after_clean = 1;
cmd.silent_exec_failure = 1;
trace_argv_printf(cmd.args.argv, "trace: exec:");
/*
* If we fail because the command is not found, it is
* OK to return. Otherwise, we just pass along the status code,
* or our usual generic code if we were not even able to exec
* the program.
*/
status = run_command(&cmd);
if (status >= 0)
exit(status);
else if (errno != ENOENT)
exit(128);
}
static int run_argv(int *argcp, const char ***argv)
{
int done_alias = 0;
while (1) {
/*
* If we tried alias and futzed with our environment,
* it no longer is safe to invoke builtins directly in
* general. We have to spawn them as dashed externals.
*
* NEEDSWORK: if we can figure out cases
* where it is safe to do, we can avoid spawning a new
* process.
*/
if (!done_alias)
handle_builtin(*argcp, *argv);
/* .. then try the external ones */
execv_dashed_external(*argv);
/* It could be an alias -- this works around the insanity
* of overriding "git log" with "git show" by having
* alias.log = show
*/
if (done_alias)
break;
if (!handle_alias(argcp, argv))
break;
done_alias = 1;
}
return done_alias;
}
int cmd_main(int argc, const char **argv)
{
const char *cmd;
int done_help = 0;
cmd = argv[0];
if (!cmd)
cmd = "git-help";
else {
const char *slash = find_last_dir_sep(cmd);
if (slash)
cmd = slash + 1;
}
trace_command_performance(argv);
/*
* "git-xxxx" is the same as "git xxxx", but we obviously:
*
* - cannot take flags in between the "git" and the "xxxx".
* - cannot execute it externally (since it would just do
* the same thing over again)
*
* So we just directly call the builtin handler, and die if
* that one cannot handle it.
*/
if (skip_prefix(cmd, "git-", &cmd)) {
argv[0] = cmd;
handle_builtin(argc, argv);
die("cannot handle %s as a builtin", cmd);
}
/* Look for flags.. */
argv++;
argc--;
handle_options(&argv, &argc, NULL);
if (argc > 0) {
/* translate --help and --version into commands */
skip_prefix(argv[0], "--", &argv[0]);
} else {
/* The user didn't specify a command; give them help */
commit_pager_choice();
printf("usage: %s\n\n", git_usage_string);
list_common_cmds_help();
printf("\n%s\n", _(git_more_info_string));
exit(1);
}
cmd = argv[0];
/*
* We use PATH to find git commands, but we prepend some higher
* precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
* environment, and the $(gitexecdir) from the Makefile at build
* time.
*/
setup_path();
while (1) {
int was_alias = run_argv(&argc, &argv);
if (errno != ENOENT)
break;
if (was_alias) {
fprintf(stderr, "Expansion of alias '%s' failed; "
"'%s' is not a git command\n",
cmd, argv[0]);
exit(1);
}
if (!done_help) {
cmd = argv[0] = help_unknown_cmd(cmd);
done_help = 1;
} else
break;
}
fprintf(stderr, "Failed to run command '%s': %s\n",
cmd, strerror(errno));
return 1;
}
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