mirror of
https://github.com/git/git
synced 2024-08-25 02:35:46 +00:00
![Junio C Hamano](/assets/img/avatar_default.png)
Earlier, when pushing into a repository that borrows from alternate object stores, we followed the longstanding design decision not to trust refs in the alternate repository that houses the object store we are borrowing from. If your public repository is borrowing from Linus's public repository, you pushed into it long time ago, and now when you try to push your updated history that is in sync with more recent history from Linus, you will end up sending not just your own development, but also the changes you acquired through Linus's tree, even though the objects needed for the latter already exists at the receiving end. This is because the receiving end does not advertise that the objects only reachable from the borrowed repository (i.e. Linus's) are already available there. This solves the issue by making the receiving end advertise refs from borrowed repositories. They are not sent with their true names but with a phoney name ".have" to make sure that the old senders will safely ignore them (otherwise, the old senders will misbehave, trying to push matching refs, and mirror push that deletes refs that only exist at the receiving end). Signed-off-by: Junio C Hamano <gitster@pobox.com>
559 lines
13 KiB
C
559 lines
13 KiB
C
#include "cache.h"
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#include "pack.h"
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#include "refs.h"
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#include "pkt-line.h"
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#include "run-command.h"
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#include "exec_cmd.h"
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#include "commit.h"
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#include "object.h"
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#include "remote.h"
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#include "transport.h"
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static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
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static int deny_non_fast_forwards = 0;
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static int receive_fsck_objects;
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static int receive_unpack_limit = -1;
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static int transfer_unpack_limit = -1;
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static int unpack_limit = 100;
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static int report_status;
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static char capabilities[] = " report-status delete-refs ";
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static int capabilities_sent;
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static int receive_pack_config(const char *var, const char *value, void *cb)
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{
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if (strcmp(var, "receive.denynonfastforwards") == 0) {
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deny_non_fast_forwards = git_config_bool(var, value);
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return 0;
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}
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if (strcmp(var, "receive.unpacklimit") == 0) {
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receive_unpack_limit = git_config_int(var, value);
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return 0;
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}
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if (strcmp(var, "transfer.unpacklimit") == 0) {
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transfer_unpack_limit = git_config_int(var, value);
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return 0;
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}
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if (strcmp(var, "receive.fsckobjects") == 0) {
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receive_fsck_objects = git_config_bool(var, value);
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return 0;
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}
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return git_default_config(var, value, cb);
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}
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static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
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{
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if (capabilities_sent)
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packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
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else
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packet_write(1, "%s %s%c%s\n",
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sha1_to_hex(sha1), path, 0, capabilities);
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capabilities_sent = 1;
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return 0;
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}
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static void write_head_info(void)
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{
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for_each_ref(show_ref, NULL);
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if (!capabilities_sent)
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show_ref("capabilities^{}", null_sha1, 0, NULL);
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}
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struct command {
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struct command *next;
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const char *error_string;
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unsigned char old_sha1[20];
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unsigned char new_sha1[20];
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char ref_name[FLEX_ARRAY]; /* more */
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};
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static struct command *commands;
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static const char pre_receive_hook[] = "hooks/pre-receive";
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static const char post_receive_hook[] = "hooks/post-receive";
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static int hook_status(int code, const char *hook_name)
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{
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switch (code) {
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case 0:
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return 0;
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case -ERR_RUN_COMMAND_FORK:
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return error("hook fork failed");
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case -ERR_RUN_COMMAND_EXEC:
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return error("hook execute failed");
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case -ERR_RUN_COMMAND_PIPE:
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return error("hook pipe failed");
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case -ERR_RUN_COMMAND_WAITPID:
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return error("waitpid failed");
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case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
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return error("waitpid is confused");
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case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
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return error("%s died of signal", hook_name);
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case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
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return error("%s died strangely", hook_name);
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default:
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error("%s exited with error code %d", hook_name, -code);
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return -code;
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}
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}
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static int run_hook(const char *hook_name)
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{
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static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
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struct command *cmd;
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struct child_process proc;
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const char *argv[2];
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int have_input = 0, code;
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for (cmd = commands; !have_input && cmd; cmd = cmd->next) {
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if (!cmd->error_string)
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have_input = 1;
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}
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if (!have_input || access(hook_name, X_OK) < 0)
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return 0;
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argv[0] = hook_name;
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argv[1] = NULL;
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memset(&proc, 0, sizeof(proc));
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proc.argv = argv;
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proc.in = -1;
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proc.stdout_to_stderr = 1;
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code = start_command(&proc);
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if (code)
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return hook_status(code, hook_name);
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for (cmd = commands; cmd; cmd = cmd->next) {
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if (!cmd->error_string) {
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size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
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sha1_to_hex(cmd->old_sha1),
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sha1_to_hex(cmd->new_sha1),
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cmd->ref_name);
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if (write_in_full(proc.in, buf, n) != n)
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break;
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}
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}
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close(proc.in);
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return hook_status(finish_command(&proc), hook_name);
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}
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static int run_update_hook(struct command *cmd)
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{
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static const char update_hook[] = "hooks/update";
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struct child_process proc;
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const char *argv[5];
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if (access(update_hook, X_OK) < 0)
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return 0;
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argv[0] = update_hook;
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argv[1] = cmd->ref_name;
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argv[2] = sha1_to_hex(cmd->old_sha1);
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argv[3] = sha1_to_hex(cmd->new_sha1);
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argv[4] = NULL;
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memset(&proc, 0, sizeof(proc));
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proc.argv = argv;
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proc.no_stdin = 1;
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proc.stdout_to_stderr = 1;
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return hook_status(run_command(&proc), update_hook);
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}
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static const char *update(struct command *cmd)
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{
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const char *name = cmd->ref_name;
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unsigned char *old_sha1 = cmd->old_sha1;
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unsigned char *new_sha1 = cmd->new_sha1;
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struct ref_lock *lock;
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/* only refs/... are allowed */
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if (prefixcmp(name, "refs/") || check_ref_format(name + 5)) {
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error("refusing to create funny ref '%s' remotely", name);
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return "funny refname";
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}
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if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
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error("unpack should have generated %s, "
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"but I can't find it!", sha1_to_hex(new_sha1));
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return "bad pack";
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}
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if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
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!is_null_sha1(old_sha1) &&
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!prefixcmp(name, "refs/heads/")) {
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struct object *old_object, *new_object;
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struct commit *old_commit, *new_commit;
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struct commit_list *bases, *ent;
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old_object = parse_object(old_sha1);
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new_object = parse_object(new_sha1);
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if (!old_object || !new_object ||
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old_object->type != OBJ_COMMIT ||
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new_object->type != OBJ_COMMIT) {
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error("bad sha1 objects for %s", name);
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return "bad ref";
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}
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old_commit = (struct commit *)old_object;
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new_commit = (struct commit *)new_object;
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bases = get_merge_bases(old_commit, new_commit, 1);
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for (ent = bases; ent; ent = ent->next)
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if (!hashcmp(old_sha1, ent->item->object.sha1))
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break;
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free_commit_list(bases);
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if (!ent) {
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error("denying non-fast forward %s"
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" (you should pull first)", name);
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return "non-fast forward";
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}
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}
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if (run_update_hook(cmd)) {
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error("hook declined to update %s", name);
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return "hook declined";
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}
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if (is_null_sha1(new_sha1)) {
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if (!parse_object(old_sha1)) {
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warning ("Allowing deletion of corrupt ref.");
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old_sha1 = NULL;
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}
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if (delete_ref(name, old_sha1)) {
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error("failed to delete %s", name);
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return "failed to delete";
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}
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return NULL; /* good */
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}
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else {
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lock = lock_any_ref_for_update(name, old_sha1, 0);
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if (!lock) {
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error("failed to lock %s", name);
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return "failed to lock";
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}
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if (write_ref_sha1(lock, new_sha1, "push")) {
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return "failed to write"; /* error() already called */
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}
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return NULL; /* good */
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}
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}
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static char update_post_hook[] = "hooks/post-update";
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static void run_update_post_hook(struct command *cmd)
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{
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struct command *cmd_p;
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int argc;
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const char **argv;
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for (argc = 0, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
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if (cmd_p->error_string)
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continue;
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argc++;
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}
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if (!argc || access(update_post_hook, X_OK) < 0)
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return;
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argv = xmalloc(sizeof(*argv) * (2 + argc));
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argv[0] = update_post_hook;
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for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
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char *p;
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if (cmd_p->error_string)
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continue;
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p = xmalloc(strlen(cmd_p->ref_name) + 1);
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strcpy(p, cmd_p->ref_name);
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argv[argc] = p;
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argc++;
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}
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argv[argc] = NULL;
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run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
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| RUN_COMMAND_STDOUT_TO_STDERR);
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}
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static void execute_commands(const char *unpacker_error)
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{
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struct command *cmd = commands;
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if (unpacker_error) {
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while (cmd) {
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cmd->error_string = "n/a (unpacker error)";
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cmd = cmd->next;
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}
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return;
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}
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if (run_hook(pre_receive_hook)) {
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while (cmd) {
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cmd->error_string = "pre-receive hook declined";
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cmd = cmd->next;
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}
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return;
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}
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while (cmd) {
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cmd->error_string = update(cmd);
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cmd = cmd->next;
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}
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}
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static void read_head_info(void)
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{
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struct command **p = &commands;
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for (;;) {
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static char line[1000];
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unsigned char old_sha1[20], new_sha1[20];
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struct command *cmd;
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char *refname;
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int len, reflen;
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len = packet_read_line(0, line, sizeof(line));
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if (!len)
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break;
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if (line[len-1] == '\n')
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line[--len] = 0;
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if (len < 83 ||
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line[40] != ' ' ||
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line[81] != ' ' ||
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get_sha1_hex(line, old_sha1) ||
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get_sha1_hex(line + 41, new_sha1))
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die("protocol error: expected old/new/ref, got '%s'",
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line);
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refname = line + 82;
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reflen = strlen(refname);
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if (reflen + 82 < len) {
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if (strstr(refname + reflen + 1, "report-status"))
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report_status = 1;
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}
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cmd = xmalloc(sizeof(struct command) + len - 80);
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hashcpy(cmd->old_sha1, old_sha1);
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hashcpy(cmd->new_sha1, new_sha1);
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memcpy(cmd->ref_name, line + 82, len - 81);
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cmd->error_string = NULL;
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cmd->next = NULL;
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*p = cmd;
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p = &cmd->next;
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}
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}
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static const char *parse_pack_header(struct pack_header *hdr)
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{
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switch (read_pack_header(0, hdr)) {
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case PH_ERROR_EOF:
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return "eof before pack header was fully read";
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case PH_ERROR_PACK_SIGNATURE:
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return "protocol error (pack signature mismatch detected)";
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case PH_ERROR_PROTOCOL:
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return "protocol error (pack version unsupported)";
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default:
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return "unknown error in parse_pack_header";
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case 0:
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return NULL;
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}
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}
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static const char *pack_lockfile;
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static const char *unpack(void)
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{
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struct pack_header hdr;
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const char *hdr_err;
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char hdr_arg[38];
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hdr_err = parse_pack_header(&hdr);
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if (hdr_err)
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return hdr_err;
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snprintf(hdr_arg, sizeof(hdr_arg),
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"--pack_header=%"PRIu32",%"PRIu32,
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ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
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if (ntohl(hdr.hdr_entries) < unpack_limit) {
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int code, i = 0;
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const char *unpacker[4];
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unpacker[i++] = "unpack-objects";
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if (receive_fsck_objects)
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unpacker[i++] = "--strict";
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unpacker[i++] = hdr_arg;
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unpacker[i++] = NULL;
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code = run_command_v_opt(unpacker, RUN_GIT_CMD);
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switch (code) {
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case 0:
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return NULL;
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case -ERR_RUN_COMMAND_FORK:
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return "unpack fork failed";
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case -ERR_RUN_COMMAND_EXEC:
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return "unpack execute failed";
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case -ERR_RUN_COMMAND_WAITPID:
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return "waitpid failed";
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case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
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return "waitpid is confused";
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case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
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return "unpacker died of signal";
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case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
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return "unpacker died strangely";
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default:
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return "unpacker exited with error code";
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}
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} else {
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const char *keeper[7];
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int s, status, i = 0;
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char keep_arg[256];
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struct child_process ip;
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s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
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if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
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strcpy(keep_arg + s, "localhost");
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keeper[i++] = "index-pack";
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keeper[i++] = "--stdin";
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if (receive_fsck_objects)
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keeper[i++] = "--strict";
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keeper[i++] = "--fix-thin";
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keeper[i++] = hdr_arg;
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keeper[i++] = keep_arg;
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keeper[i++] = NULL;
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memset(&ip, 0, sizeof(ip));
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ip.argv = keeper;
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ip.out = -1;
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ip.git_cmd = 1;
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if (start_command(&ip))
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return "index-pack fork failed";
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pack_lockfile = index_pack_lockfile(ip.out);
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close(ip.out);
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status = finish_command(&ip);
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if (!status) {
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reprepare_packed_git();
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return NULL;
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}
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return "index-pack abnormal exit";
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}
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}
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static void report(const char *unpack_status)
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{
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struct command *cmd;
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packet_write(1, "unpack %s\n",
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unpack_status ? unpack_status : "ok");
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for (cmd = commands; cmd; cmd = cmd->next) {
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if (!cmd->error_string)
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packet_write(1, "ok %s\n",
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cmd->ref_name);
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else
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packet_write(1, "ng %s %s\n",
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cmd->ref_name, cmd->error_string);
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}
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packet_flush(1);
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}
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static int delete_only(struct command *cmd)
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{
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while (cmd) {
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if (!is_null_sha1(cmd->new_sha1))
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return 0;
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cmd = cmd->next;
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}
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return 1;
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}
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static int add_refs_from_alternate(struct alternate_object_database *e, void *unused)
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{
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char *other = xstrdup(make_absolute_path(e->base));
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size_t len = strlen(other);
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struct remote *remote;
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struct transport *transport;
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const struct ref *extra;
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while (other[len-1] == '/')
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other[--len] = '\0';
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if (len < 8 || memcmp(other + len - 8, "/objects", 8))
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return 0;
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/* Is this a git repository with refs? */
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memcpy(other + len - 8, "/refs", 6);
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if (!is_directory(other))
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return 0;
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other[len - 8] = '\0';
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remote = remote_get(other);
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transport = transport_get(remote, other);
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for (extra = transport_get_remote_refs(transport);
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extra;
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extra = extra->next) {
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add_extra_ref(".have", extra->old_sha1, 0);
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}
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transport_disconnect(transport);
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free(other);
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return 0;
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}
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static void add_alternate_refs(void)
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{
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foreach_alt_odb(add_refs_from_alternate, NULL);
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}
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int cmd_receive_pack(int argc, const char **argv, const char *prefix)
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{
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int i;
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char *dir = NULL;
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argv++;
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for (i = 1; i < argc; i++) {
|
|
const char *arg = *argv++;
|
|
|
|
if (*arg == '-') {
|
|
/* Do flag handling here */
|
|
usage(receive_pack_usage);
|
|
}
|
|
if (dir)
|
|
usage(receive_pack_usage);
|
|
dir = xstrdup(arg);
|
|
}
|
|
if (!dir)
|
|
usage(receive_pack_usage);
|
|
|
|
setup_path();
|
|
|
|
if (!enter_repo(dir, 0))
|
|
die("'%s': unable to chdir or not a git archive", dir);
|
|
|
|
if (is_repository_shallow())
|
|
die("attempt to push into a shallow repository");
|
|
|
|
git_config(receive_pack_config, NULL);
|
|
|
|
if (0 <= transfer_unpack_limit)
|
|
unpack_limit = transfer_unpack_limit;
|
|
else if (0 <= receive_unpack_limit)
|
|
unpack_limit = receive_unpack_limit;
|
|
|
|
add_alternate_refs();
|
|
write_head_info();
|
|
clear_extra_refs();
|
|
|
|
/* EOF */
|
|
packet_flush(1);
|
|
|
|
read_head_info();
|
|
if (commands) {
|
|
const char *unpack_status = NULL;
|
|
|
|
if (!delete_only(commands))
|
|
unpack_status = unpack();
|
|
execute_commands(unpack_status);
|
|
if (pack_lockfile)
|
|
unlink(pack_lockfile);
|
|
if (report_status)
|
|
report(unpack_status);
|
|
run_hook(post_receive_hook);
|
|
run_update_post_hook(commands);
|
|
}
|
|
return 0;
|
|
}
|