Revision 6bc0cb5176a5e42ca4a74e3558e8f0790ed09bb1 authored by Jeff King on 20 May 2015, 07:37:09 UTC, committed by Junio C Hamano on 26 May 2015, 03:43:18 UTC
When http-backend spawns "upload-pack" to do ref negotiation, it streams the http request body to upload-pack, who then streams the http response back to the client as it reads. In theory, git can go full-duplex; the client can consume our response while it is still sending the request. In practice, however, HTTP is a half-duplex protocol. Even if our client is ready to read and write simultaneously, we may have other HTTP infrastructure in the way, including the webserver that spawns our CGI, or any intermediate proxies. In at least one documented case[1], this leads to deadlock when trying a fetch over http. What happens is basically: 1. Apache proxies the request to the CGI, http-backend. 2. http-backend gzip-inflates the data and sends the result to upload-pack. 3. upload-pack acts on the data and generates output over the pipe back to Apache. Apache isn't reading because it's busy writing (step 1). This works fine most of the time, because the upload-pack output ends up in a system pipe buffer, and Apache reads it as soon as it finishes writing. But if both the request and the response exceed the system pipe buffer size, then we deadlock (Apache blocks writing to http-backend, http-backend blocks writing to upload-pack, and upload-pack blocks writing to Apache). We need to break the deadlock by spooling either the input or the output. In this case, it's ideal to spool the input, because Apache does not start reading either stdout _or_ stderr until we have consumed all of the input. So until we do so, we cannot even get an error message out to the client. The solution is fairly straight-forward: we read the request body into an in-memory buffer in http-backend, freeing up Apache, and then feed the data ourselves to upload-pack. But there are a few important things to note: 1. We limit the in-memory buffer to prevent an obvious denial-of-service attack. This is a new hard limit on requests, but it's unlikely to come into play. The default value is 10MB, which covers even the ridiculous 100,000-ref negotation in the included test (that actually caps out just over 5MB). But it's configurable on the off chance that you don't mind spending some extra memory to make even ridiculous requests work. 2. We must take care only to buffer when we have to. For pushes, the incoming packfile may be of arbitrary size, and we should connect the input directly to receive-pack. There's no deadlock problem here, though, because we do not produce any output until the whole packfile has been read. For upload-pack's initial ref advertisement, we similarly do not need to buffer. Even though we may generate a lot of output, there is no request body at all (i.e., it is a GET, not a POST). [1] http://article.gmane.org/gmane.comp.version-control.git/269020 Test-adapted-from: Dennis Kaarsemaker <dennis@kaarsemaker.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent cc969c8
git.c
#include "builtin.h"
#include "cache.h"
#include "exec_cmd.h"
#include "help.h"
#include "quote.h"
#include "run-command.h"
#include "commit.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 struct startup_info git_startup_info;
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 saved_environment;
static void save_env(void)
{
int i;
if (saved_environment)
return;
saved_environment = 1;
orig_cwd = xgetcwd();
for (i = 0; i < ARRAY_SIZE(env_names); i++) {
orig_env[i] = getenv(env_names[i]);
if (orig_env[i])
orig_env[i] = xstrdup(orig_env[i]);
}
}
static void restore_env(void)
{
int i;
if (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 (orig_env[i])
setenv(env_names[i], orig_env[i], 1);
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, "--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 (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;
const char *subdir;
int count, option_count;
const char **new_argv;
const char *alias_command;
char *alias_string;
int unused_nongit;
subdir = setup_git_directory_gently(&unused_nongit);
alias_command = (*argv)[0];
alias_string = alias_lookup(alias_command);
if (alias_string) {
if (alias_string[0] == '!') {
const char **alias_argv;
int argc = *argcp, i;
commit_pager_choice();
/* build alias_argv */
alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
alias_argv[0] = alias_string + 1;
for (i = 1; i < argc; ++i)
alias_argv[i] = (*argv)[i];
alias_argv[argc] = NULL;
ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
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;
}
if (subdir && chdir(subdir))
die_errno("Cannot change to '%s'", subdir);
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 NO_SETUP (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 && 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 },
{ "annotate", cmd_annotate, RUN_SETUP },
{ "apply", cmd_apply, RUN_SETUP_GENTLY },
{ "archive", cmd_archive },
{ "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, NO_SETUP },
{ "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, NO_SETUP },
{ "init-db", cmd_init_db, NO_SETUP },
{ "interpret-trailers", cmd_interpret_trailers, RUN_SETUP },
{ "log", cmd_log, RUN_SETUP },
{ "ls-files", cmd_ls_files, RUN_SETUP },
{ "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
{ "ls-tree", cmd_ls_tree, RUN_SETUP },
{ "mailinfo", cmd_mailinfo },
{ "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 },
{ "pickaxe", cmd_blame, RUN_SETUP },
{ "prune", cmd_prune, RUN_SETUP },
{ "prune-packed", cmd_prune_packed, RUN_SETUP },
{ "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 },
{ "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 },
{ "write-tree", cmd_write_tree, RUN_SETUP },
};
int is_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 1;
}
return 0;
}
static void handle_builtin(int argc, const char **argv)
{
const char *cmd = argv[0];
int i;
static const char ext[] = STRIP_EXTENSION;
if (sizeof(ext) > 1) {
i = strlen(argv[0]) - strlen(ext);
if (i > 0 && !strcmp(argv[0] + i, ext)) {
char *argv0 = xstrdup(argv[0]);
argv[0] = cmd = argv0;
argv0[i] = '\0';
}
}
/* Turn "git cmd --help" into "git help cmd" */
if (argc > 1 && !strcmp(argv[1], "--help")) {
argv[1] = argv[0];
argv[0] = cmd = "help";
}
for (i = 0; i < ARRAY_SIZE(commands); i++) {
struct cmd_struct *p = commands+i;
if (strcmp(p->cmd, cmd))
continue;
if (saved_environment && (p->option & NO_SETUP)) {
restore_env();
break;
}
exit(run_builtin(p, argc, argv));
}
}
static void execv_dashed_external(const char **argv)
{
struct strbuf cmd = STRBUF_INIT;
const char *tmp;
int status;
if (use_pager == -1)
use_pager = check_pager_config(argv[0]);
commit_pager_choice();
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, "trace: exec:");
/*
* if we fail because the command is not found, it is
* OK to return. Otherwise, we just pass along the status code.
*/
status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
if (status >= 0 || errno != ENOENT)
exit(status);
argv[0] = tmp;
strbuf_release(&cmd);
}
static int run_argv(int *argcp, const char ***argv)
{
int done_alias = 0;
while (1) {
/* See if it's a builtin */
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;
save_env();
if (!handle_alias(argcp, argv))
break;
done_alias = 1;
}
return done_alias;
}
/*
* Many parts of Git have subprograms communicate via pipe, expect the
* upstream of a pipe to die with SIGPIPE when the downstream of a
* pipe does not need to read all that is written. Some third-party
* programs that ignore or block SIGPIPE for their own reason forget
* to restore SIGPIPE handling to the default before spawning Git and
* break this carefully orchestrated machinery.
*
* Restore the way SIGPIPE is handled to default, which is what we
* expect.
*/
static void restore_sigpipe_to_default(void)
{
sigset_t unblock;
sigemptyset(&unblock);
sigaddset(&unblock, SIGPIPE);
sigprocmask(SIG_UNBLOCK, &unblock, NULL);
signal(SIGPIPE, SIG_DFL);
}
int main(int argc, char **av)
{
const char **argv = (const char **) av;
const char *cmd;
startup_info = &git_startup_info;
cmd = git_extract_argv0_path(argv[0]);
if (!cmd)
cmd = "git-help";
/*
* Always open file descriptors 0/1/2 to avoid clobbering files
* in die(). It also avoids messing up when the pipes are dup'ed
* onto stdin/stdout/stderr in the child processes we spawn.
*/
sanitize_stdfds();
restore_sigpipe_to_default();
git_setup_gettext();
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) {
static int done_help = 0;
static int was_alias = 0;
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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