git/builtin/credential-store.c
Simão Afonso df7f915fb6 crendential-store: use timeout when locking file
When holding the lock for rewriting the credential file, use a timeout
to avoid race conditions when the credentials file needs to be updated
in parallel.

An example would be doing `fetch --all` on a repository with several
remotes that need credentials, using parallel fetching.

The timeout can be configured using "credentialStore.lockTimeoutMS",
defaulting to 1 second.

Signed-off-by: Simão Afonso <simao.afonso@powertools-tech.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-25 12:30:18 -08:00

200 lines
5.3 KiB
C

#include "builtin.h"
#include "config.h"
#include "lockfile.h"
#include "credential.h"
#include "string-list.h"
#include "parse-options.h"
static struct lock_file credential_lock;
static int parse_credential_file(const char *fn,
struct credential *c,
void (*match_cb)(struct credential *),
void (*other_cb)(struct strbuf *))
{
FILE *fh;
struct strbuf line = STRBUF_INIT;
struct credential entry = CREDENTIAL_INIT;
int found_credential = 0;
fh = fopen(fn, "r");
if (!fh) {
if (errno != ENOENT && errno != EACCES)
die_errno("unable to open %s", fn);
return found_credential;
}
while (strbuf_getline_lf(&line, fh) != EOF) {
if (!credential_from_url_gently(&entry, line.buf, 1) &&
entry.username && entry.password &&
credential_match(c, &entry)) {
found_credential = 1;
if (match_cb) {
match_cb(&entry);
break;
}
}
else if (other_cb)
other_cb(&line);
}
credential_clear(&entry);
strbuf_release(&line);
fclose(fh);
return found_credential;
}
static void print_entry(struct credential *c)
{
printf("username=%s\n", c->username);
printf("password=%s\n", c->password);
}
static void print_line(struct strbuf *buf)
{
strbuf_addch(buf, '\n');
write_or_die(get_lock_file_fd(&credential_lock), buf->buf, buf->len);
}
static void rewrite_credential_file(const char *fn, struct credential *c,
struct strbuf *extra)
{
int timeout_ms = 1000;
git_config_get_int("credentialstore.locktimeoutms", &timeout_ms);
if (hold_lock_file_for_update_timeout(&credential_lock, fn, 0, timeout_ms) < 0)
die_errno(_("unable to get credential storage lock in %d ms"), timeout_ms);
if (extra)
print_line(extra);
parse_credential_file(fn, c, NULL, print_line);
if (commit_lock_file(&credential_lock) < 0)
die_errno("unable to write credential store");
}
static void store_credential_file(const char *fn, struct credential *c)
{
struct strbuf buf = STRBUF_INIT;
strbuf_addf(&buf, "%s://", c->protocol);
strbuf_addstr_urlencode(&buf, c->username, is_rfc3986_unreserved);
strbuf_addch(&buf, ':');
strbuf_addstr_urlencode(&buf, c->password, is_rfc3986_unreserved);
strbuf_addch(&buf, '@');
if (c->host)
strbuf_addstr_urlencode(&buf, c->host, is_rfc3986_unreserved);
if (c->path) {
strbuf_addch(&buf, '/');
strbuf_addstr_urlencode(&buf, c->path,
is_rfc3986_reserved_or_unreserved);
}
rewrite_credential_file(fn, c, &buf);
strbuf_release(&buf);
}
static void store_credential(const struct string_list *fns, struct credential *c)
{
struct string_list_item *fn;
/*
* Sanity check that what we are storing is actually sensible.
* In particular, we can't make a URL without a protocol field.
* Without either a host or pathname (depending on the scheme),
* we have no primary key. And without a username and password,
* we are not actually storing a credential.
*/
if (!c->protocol || !(c->host || c->path) || !c->username || !c->password)
return;
for_each_string_list_item(fn, fns)
if (!access(fn->string, F_OK)) {
store_credential_file(fn->string, c);
return;
}
/*
* Write credential to the filename specified by fns->items[0], thus
* creating it
*/
if (fns->nr)
store_credential_file(fns->items[0].string, c);
}
static void remove_credential(const struct string_list *fns, struct credential *c)
{
struct string_list_item *fn;
/*
* Sanity check that we actually have something to match
* against. The input we get is a restrictive pattern,
* so technically a blank credential means "erase everything".
* But it is too easy to accidentally send this, since it is equivalent
* to empty input. So explicitly disallow it, and require that the
* pattern have some actual content to match.
*/
if (!c->protocol && !c->host && !c->path && !c->username)
return;
for_each_string_list_item(fn, fns)
if (!access(fn->string, F_OK))
rewrite_credential_file(fn->string, c, NULL);
}
static void lookup_credential(const struct string_list *fns, struct credential *c)
{
struct string_list_item *fn;
for_each_string_list_item(fn, fns)
if (parse_credential_file(fn->string, c, print_entry, NULL))
return; /* Found credential */
}
int cmd_credential_store(int argc, const char **argv, const char *prefix)
{
const char * const usage[] = {
"git credential-store [<options>] <action>",
NULL
};
const char *op;
struct credential c = CREDENTIAL_INIT;
struct string_list fns = STRING_LIST_INIT_DUP;
char *file = NULL;
struct option options[] = {
OPT_STRING(0, "file", &file, "path",
"fetch and store credentials in <path>"),
OPT_END()
};
umask(077);
argc = parse_options(argc, (const char **)argv, prefix, options, usage, 0);
if (argc != 1)
usage_with_options(usage, options);
op = argv[0];
if (file) {
string_list_append(&fns, file);
} else {
if ((file = expand_user_path("~/.git-credentials", 0)))
string_list_append_nodup(&fns, file);
file = xdg_config_home("credentials");
if (file)
string_list_append_nodup(&fns, file);
}
if (!fns.nr)
die("unable to set up default path; use --file");
if (credential_read(&c, stdin) < 0)
die("unable to read credential");
if (!strcmp(op, "get"))
lookup_credential(&fns, &c);
else if (!strcmp(op, "erase"))
remove_credential(&fns, &c);
else if (!strcmp(op, "store"))
store_credential(&fns, &c);
else
; /* Ignore unknown operation. */
string_list_clear(&fns, 0);
return 0;
}