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subsurface/core/git-access.cpp
Berthold Stoeger bfbf4934dd core: enable compiler warngings for report_error and report_info 
printf() is a horrible interface as it does no type checking.
Let's at least use the compiler to check format strings and
arguments. This obviously doesn't work for translated strings
and using report_error on translated strings is dubious. But OK.

Had to convert a number of report_error() calls to supress
warnings.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2024-03-12 10:31:07 -04:00

1161 lines
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// SPDX-License-Identifier: GPL-2.0
#ifdef __clang__
// Clang has a bug on zero-initialization of C structs.
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#endif
#include "ssrf.h"
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdarg.h>
#include <git2.h>
#include "subsurface-string.h"
#include "membuffer.h"
#include "strndup.h"
#include "qthelper.h"
#include "file.h"
#include "errorhelper.h"
#include "git-access.h"
#include "gettext.h"
#include "sha1.h"
// the mobile app assumes that it shouldn't talk to the cloud
// the desktop app assumes that it should
#if defined(SUBSURFACE_MOBILE)
bool git_local_only = true;
#else
bool git_local_only = false;
#endif
bool git_remote_sync_successful = false;
int (*update_progress_cb)(const char *) = NULL;
static bool includes_string_caseinsensitive(const char *haystack, const char *needle)
{
if (!needle)
return 1; /* every string includes the NULL string */
if (!haystack)
return 0; /* nothing is included in the NULL string */
int len = strlen(needle);
while (*haystack) {
if (strncasecmp(haystack, needle, len))
return 1;
haystack++;
}
return 0;
}
extern "C" void set_git_update_cb(int(*cb)(const char *))
{
update_progress_cb = cb;
}
// total overkill, but this allows us to get good timing in various scenarios;
// the various parts of interacting with the local and remote git repositories send
// us updates which indicate progress (and no, this is not smooth and definitely not
// proportional - some parts are based on compute performance, some on network speed)
// they also provide information where in the process we are so we can analyze the log
// to understand which parts of the process take how much time.
extern "C" int git_storage_update_progress(const char *text)
{
int ret = 0;
if (update_progress_cb)
ret = (*update_progress_cb)(text);
return ret;
}
// the checkout_progress_cb doesn't allow canceling of the operation
// map the git progress to 20% of overall progress
static void progress_cb(const char *, size_t completed_steps, size_t total_steps, void *)
{
char buf[80];
snprintf(buf, sizeof(buf), translate("gettextFromC", "Checkout from storage (%lu/%lu)"), completed_steps, total_steps);
(void)git_storage_update_progress(buf);
}
// this randomly assumes that 80% of the time is spent on the objects and 20% on the deltas
// map the git progress to 20% of overall progress
// if the user cancels the dialog this is passed back to libgit2
static int transfer_progress_cb(const git_transfer_progress *stats, void *)
{
static int last_done = -1;
char buf[80];
int done = 0;
int total = 0;
if (stats->total_objects) {
total = 60;
done = 60 * stats->received_objects / stats->total_objects;
}
if (stats->total_deltas) {
total += 20;
done += 20 * stats->indexed_deltas / stats->total_deltas;
}
/* for debugging this is useful
char buf[100];
snprintf(buf, 100, "transfer cb rec_obj %d tot_obj %d idx_delta %d total_delta %d local obj %d", stats->received_objects, stats->total_objects, stats->indexed_deltas, stats->total_deltas, stats->local_objects);
return git_storage_update_progress(buf);
*/
if (done > last_done) {
last_done = done;
snprintf(buf, sizeof(buf), translate("gettextFromC", "Transfer from storage (%d/%d)"), done, total);
return git_storage_update_progress(buf);
}
return 0;
}
// the initial push to sync the repos is mapped to 10% of overall progress
static int push_transfer_progress_cb(unsigned int current, unsigned int total, size_t, void *)
{
char buf[80];
snprintf(buf, sizeof(buf), translate("gettextFromC", "Transfer to storage (%d/%d)"), current, total);
return git_storage_update_progress(buf);
}
extern "C" char *get_local_dir(const char *url, const char *branch)
{
SHA_CTX ctx;
unsigned char hash[20];
// this optimization could in theory lead to odd things happening if the
// cloud backend servers ever get out of sync - but when a user switches
// between those servers (either because one is down, or because the algorithm
// which server to pick changed, or because the user is on a different continent),
// then the hash and therefore the local directory would change. To prevent that
// from happening, normalize the cloud string to always use the old default name.
// That's trivial with QString operations and painful to do right in plain C, so
// let's be lazy and call a C++ helper function
// just remember to free the string we get back
std::string remote = normalize_cloud_name(url);
// That zero-byte update is so that we don't get hash
// collisions for "repo1 branch" vs "repo 1branch".
SHA1_Init(&ctx);
SHA1_Update(&ctx, remote.c_str(), remote.size());
SHA1_Update(&ctx, "", 1);
SHA1_Update(&ctx, branch, strlen(branch));
SHA1_Final(hash, &ctx);
return format_string("%s/cloudstorage/%02x%02x%02x%02x%02x%02x%02x%02x",
system_default_directory(),
hash[0], hash[1], hash[2], hash[3],
hash[4], hash[5], hash[6], hash[7]);
}
static char *move_local_cache(struct git_info *info)
{
char *old_path = get_local_dir(info->url, info->branch);
char *new_path = move_away(old_path);
free(old_path);
return new_path;
}
static int check_clean(const char *path, unsigned int status, void *payload)
{
struct git_info *info = (struct git_info *)payload;
status &= ~GIT_STATUS_CURRENT | GIT_STATUS_IGNORED;
if (!status)
return 0;
SSRF_INFO("git storage: local cache dir %s modified, git status 0x%04x", path, status);
if (info->is_subsurface_cloud)
report_error(translate("gettextFromC", "Local cache directory %s corrupted - can't sync with Subsurface cloud storage"), path);
else
report_error("WARNING: Git cache directory modified (path %s) status 0x%04x", path, status);
return 1;
}
/*
* The remote is strictly newer than the local branch.
*/
static int reset_to_remote(struct git_info *info, git_reference *local, const git_oid *new_id)
{
git_checkout_options opts = GIT_CHECKOUT_OPTIONS_INIT;
opts.progress_cb = &progress_cb;
git_object *target;
if (verbose)
SSRF_INFO("git storage: reset to remote\n");
/* If it's not checked out (bare or not HEAD), just update the reference */
if (git_repository_is_bare(info->repo) || git_branch_is_head(local) != 1) {
git_reference *out;
if (git_reference_set_target(&out, local, new_id, "Update to remote")) {
SSRF_INFO("git storage: could not update local cache to newer remote data");
return report_error("%s", translate("gettextFromC", "Could not update local cache to newer remote data"));
}
git_reference_free(out);
#ifdef DEBUG
// Not really an error, just informational
report_error("Updated local branch from remote");
#endif
return 0;
}
if (git_object_lookup(&target, info->repo, new_id, GIT_OBJ_COMMIT)) {
SSRF_INFO("git storage: could not look up remote commit");
if (info->is_subsurface_cloud)
return report_error("%s", translate("gettextFromC", "Subsurface cloud storage corrupted"));
else
return report_error("Could not look up remote commit");
}
opts.checkout_strategy = GIT_CHECKOUT_SAFE;
if (git_reset(info->repo, target, GIT_RESET_HARD, &opts)) {
SSRF_INFO("git storage: local head checkout failed after update");
if (info->is_subsurface_cloud)
return report_error("%s", translate("gettextFromC", "Could not update local cache to newer remote data"));
else
return report_error("Local head checkout failed after update");
}
// Not really an error, just informational
#ifdef DEBUG
report_error("Updated local information from remote");
#endif
return 0;
}
static int auth_attempt = 0;
static const int max_auth_attempts = 2;
static bool exceeded_auth_attempts()
{
if (auth_attempt++ > max_auth_attempts) {
SSRF_INFO("git storage: authentication to cloud storage failed");
report_error("Authentication to cloud storage failed.");
return true;
}
return false;
}
extern "C" int credential_ssh_cb(git_cred **out,
const char *,
const char *,
unsigned int allowed_types,
void *)
{
const char *username = prefs.cloud_storage_email_encoded;
const char *passphrase = prefs.cloud_storage_password ? prefs.cloud_storage_password : "";
// TODO: We need a way to differentiate between password and private key authentication
if (allowed_types & GIT_CREDTYPE_SSH_KEY) {
char *priv_key = format_string("%s/%s", system_default_directory(), "ssrf_remote.key");
if (!access(priv_key, F_OK)) {
if (exceeded_auth_attempts())
return GIT_EUSER;
int ret = git_cred_ssh_key_new(out, username, NULL, priv_key, passphrase);
free(priv_key);
return ret;
}
free(priv_key);
}
if (allowed_types & GIT_CREDTYPE_USERPASS_PLAINTEXT) {
if (exceeded_auth_attempts())
return GIT_EUSER;
return git_cred_userpass_plaintext_new(out, username, passphrase);
}
if (allowed_types & GIT_CREDTYPE_USERNAME)
return git_cred_username_new(out, username);
report_error("No supported ssh authentication.");
return GIT_EUSER;
}
extern "C" int credential_https_cb(git_cred **out,
const char *,
const char *,
unsigned int,
void *)
{
if (exceeded_auth_attempts())
return GIT_EUSER;
const char *username = prefs.cloud_storage_email_encoded;
const char *password = prefs.cloud_storage_password ? prefs.cloud_storage_password : "";
return git_cred_userpass_plaintext_new(out, username, password);
}
extern "C" int certificate_check_cb(git_cert *cert, int valid, const char *host, void *)
{
if (verbose)
SSRF_INFO("git storage: certificate callback for host %s with validity %d\n", host, valid);
if ((same_string(host, CLOUD_HOST_GENERIC) ||
same_string(host, CLOUD_HOST_US) ||
same_string(host, CLOUD_HOST_U2) ||
same_string(host, CLOUD_HOST_EU) ||
same_string(host, CLOUD_HOST_E2)) &&
cert->cert_type == GIT_CERT_X509) {
// for some reason the LetsEncrypt certificate makes libgit2 throw up on some
// platforms but not on others
// if we are connecting to the cloud server we alrady called 'canReachCloudServer()'
// which will fail if the SSL certificate isn't valid, so let's simply always
// tell the caller that this certificate is valid
return 0;
}
return valid ? 0 : -1;
}
static int update_remote(struct git_info *info, git_remote *origin, git_reference *local, git_reference *)
{
git_push_options opts = GIT_PUSH_OPTIONS_INIT;
git_strarray refspec;
const char *name = git_reference_name(local);
if (verbose)
SSRF_INFO("git storage: update remote\n");
refspec.count = 1;
refspec.strings = (char **)&name;
auth_attempt = 0;
opts.callbacks.push_transfer_progress = &push_transfer_progress_cb;
if (info->transport == RT_SSH)
opts.callbacks.credentials = credential_ssh_cb;
else if (info->transport == RT_HTTPS)
opts.callbacks.credentials = credential_https_cb;
opts.callbacks.certificate_check = certificate_check_cb;
if (git_remote_push(origin, &refspec, &opts)) {
const char *msg = giterr_last()->message;
SSRF_INFO("git storage: unable to update remote with current local cache state, error: %s", msg);
if (info->is_subsurface_cloud)
return report_error("%s", translate("gettextFromC", "Could not update Subsurface cloud storage, try again later"));
else
return report_error("Unable to update remote with current local cache state (%s)", msg);
}
return 0;
}
extern "C" int update_git_checkout(git_repository *repo, git_object *parent, git_tree *tree);
static int try_to_git_merge(struct git_info *info, git_reference **local_p, git_reference *, git_oid *base, const git_oid *local_id, const git_oid *remote_id)
{
git_tree *local_tree, *remote_tree, *base_tree;
git_commit *local_commit, *remote_commit, *base_commit;
git_index *merged_index;
git_merge_options merge_options;
struct membuffer msg = { 0, 0, NULL};
if (verbose) {
char outlocal[41], outremote[41];
outlocal[40] = outremote[40] = 0;
git_oid_fmt(outlocal, local_id);
git_oid_fmt(outremote, remote_id);
SSRF_INFO("git storage: trying to merge local SHA %s remote SHA %s\n", outlocal, outremote);
}
git_merge_init_options(&merge_options, GIT_MERGE_OPTIONS_VERSION);
merge_options.flags = GIT_MERGE_FIND_RENAMES;
merge_options.file_favor = GIT_MERGE_FILE_FAVOR_UNION;
merge_options.rename_threshold = 100;
if (git_commit_lookup(&local_commit, info->repo, local_id)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: can't get commit (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_commit_tree(&local_tree, local_commit)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: failed local tree lookup (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_commit_lookup(&remote_commit, info->repo, remote_id)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: can't get commit (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_commit_tree(&remote_tree, remote_commit)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: failed local tree lookup (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_commit_lookup(&base_commit, info->repo, base)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: can't get commit (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_commit_tree(&base_tree, base_commit)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: failed base tree lookup (%s)", giterr_last()->message);
goto diverged_error;
}
if (git_merge_trees(&merged_index, info->repo, base_tree, local_tree, remote_tree, &merge_options)) {
SSRF_INFO("git storage: remote storage and local data diverged. Error: merge failed (%s)", giterr_last()->message);
// this is the one where I want to report more detail to the user - can't quite explain why
return report_error(translate("gettextFromC", "Remote storage and local data diverged. Error: merge failed (%s)"), giterr_last()->message);
}
if (git_index_has_conflicts(merged_index)) {
int error;
const git_index_entry *ancestor = NULL,
*ours = NULL,
*theirs = NULL;
git_index_conflict_iterator *iter = NULL;
error = git_index_conflict_iterator_new(&iter, merged_index);
while (git_index_conflict_next(&ancestor, &ours, &theirs, iter)
!= GIT_ITEROVER) {
/* Mark this conflict as resolved */
SSRF_INFO("git storage: conflict in %s / %s / %s -- ",
ours ? ours->path : "-",
theirs ? theirs->path : "-",
ancestor ? ancestor->path : "-");
if ((!ours && theirs && ancestor) ||
(ours && !theirs && ancestor)) {
// the file was removed on one side or the other - just remove it
SSRF_INFO("git storage: looks like a delete on one side; removing the file from the index\n");
error = git_index_remove(merged_index, ours ? ours->path : theirs->path, GIT_INDEX_STAGE_ANY);
} else if (ancestor) {
error = git_index_conflict_remove(merged_index, ours ? ours->path : theirs ? theirs->path : ancestor->path);
}
if (error) {
SSRF_INFO("git storage: error at conflict resolution (%s)", giterr_last()->message);
}
}
git_index_conflict_cleanup(merged_index);
git_index_conflict_iterator_free(iter);
report_error("%s", translate("gettextFromC", "Remote storage and local data diverged. Cannot combine local and remote changes"));
}
{
git_oid merge_oid, commit_oid;
git_tree *merged_tree;
git_signature *author;
git_commit *commit;
if (git_index_write_tree_to(&merge_oid, merged_index, info->repo))
goto write_error;
if (git_tree_lookup(&merged_tree, info->repo, &merge_oid))
goto write_error;
if (get_authorship(info->repo, &author) < 0)
goto write_error;
std::string user_agent = subsurface_user_agent();
put_format(&msg, "Automatic merge\n\nCreated by %s\n", user_agent.c_str());
if (git_commit_create_v(&commit_oid, info->repo, NULL, author, author, NULL, mb_cstring(&msg), merged_tree, 2, local_commit, remote_commit))
goto write_error;
if (git_commit_lookup(&commit, info->repo, &commit_oid))
goto write_error;
if (git_branch_is_head(*local_p) && !git_repository_is_bare(info->repo)) {
git_object *parent;
git_reference_peel(&parent, *local_p, GIT_OBJ_COMMIT);
if (update_git_checkout(info->repo, parent, merged_tree)) {
goto write_error;
}
}
if (git_reference_set_target(local_p, *local_p, &commit_oid, "Subsurface merge event"))
goto write_error;
set_git_id(&commit_oid);
git_signature_free(author);
if (verbose)
SSRF_INFO("git storage: successfully merged repositories");
free_buffer(&msg);
return 0;
}
diverged_error:
return report_error("%s", translate("gettextFromC", "Remote storage and local data diverged"));
write_error:
free_buffer(&msg);
return report_error(translate("gettextFromC", "Remote storage and local data diverged. Error: writing the data failed (%s)"), giterr_last()->message);
}
// if accessing the local cache of Subsurface cloud storage fails, we simplify things
// for the user and simply move the cache away (in case they want to try and extract data)
// and ask them to retry the operation (which will then refresh the data from the cloud server)
static int cleanup_local_cache(struct git_info *info)
{
char *backup_path = move_local_cache(info);
SSRF_INFO("git storage: problems with local cache, moved to %s", backup_path);
report_error("%s", translate("gettextFromC", "Problems with local cache of Subsurface cloud data"));
report_error(translate("gettextFromC", "Moved cache data to %s. Please try the operation again."), backup_path);
free(backup_path);
return -1;
}
static int try_to_update(struct git_info *info, git_remote *origin, git_reference *local, git_reference *remote)
{
git_oid base;
const git_oid *local_id, *remote_id;
int ret = 0;
if (verbose)
SSRF_INFO("git storage: try to update\n");
if (!git_reference_cmp(local, remote))
return 0;
// Dirty modified state in the working tree? We're not going
// to update either way
if (git_status_foreach(info->repo, check_clean, (void *)info)) {
SSRF_INFO("git storage: local cache is dirty, skipping update");
if (info->is_subsurface_cloud)
goto cloud_data_error;
else
return report_error("local cached copy is dirty, skipping update");
}
local_id = git_reference_target(local);
remote_id = git_reference_target(remote);
if (!local_id || !remote_id) {
if (!local_id)
SSRF_INFO("git storage: unable to get local SHA");
if (!remote_id)
SSRF_INFO("git storage: unable to get remote SHA");
if (info->is_subsurface_cloud)
goto cloud_data_error;
else
return report_error("Unable to get local or remote SHA1");
}
if (git_merge_base(&base, info->repo, local_id, remote_id)) {
// TODO:
// if they have no merge base, they actually are different repos
// so instead merge this as merging a commit into a repo - git_merge() appears to do that
// but needs testing and cleanup afterwards
//
SSRF_INFO("git storage: no common commit between local and remote branches");
if (info->is_subsurface_cloud)
goto cloud_data_error;
else
return report_error("Unable to find common commit of local and remote branches");
}
/* Is the remote strictly newer? Use it */
if (git_oid_equal(&base, local_id)) {
if (verbose)
SSRF_INFO("git storage: remote is newer than local, update local");
git_storage_update_progress(translate("gettextFromC", "Update local storage to match cloud storage"));
return reset_to_remote(info, local, remote_id);
}
/* Is the local repo the more recent one? See if we can update upstream */
if (git_oid_equal(&base, remote_id)) {
if (verbose)
SSRF_INFO("git storage: local is newer than remote, update remote");
git_storage_update_progress(translate("gettextFromC", "Push local changes to cloud storage"));
return update_remote(info, origin, local, remote);
}
/* Merging a bare repository always needs user action */
if (git_repository_is_bare(info->repo)) {
SSRF_INFO("git storage: local is bare and has diverged from remote; user action needed");
if (info->is_subsurface_cloud)
goto cloud_data_error;
else
return report_error("Local and remote have diverged, merge of bare branch needed");
}
/* Merging will definitely need the head branch too */
if (git_branch_is_head(local) != 1) {
SSRF_INFO("git storage: local branch is not HEAD, cannot merge");
if (info->is_subsurface_cloud)
goto cloud_data_error;
else
return report_error("Local and remote do not match, local branch not HEAD - cannot update");
}
/* Ok, let's try to merge these */
git_storage_update_progress(translate("gettextFromC", "Try to merge local changes into cloud storage"));
ret = try_to_git_merge(info, &local, remote, &base, local_id, remote_id);
if (ret == 0)
return update_remote(info, origin, local, remote);
else
return ret;
cloud_data_error:
// since we are working with Subsurface cloud storage we want to make the user interaction
// as painless as possible. So if something went wrong with the local cache, tell the user
// about it an move it away
return cleanup_local_cache(info);
}
static int check_remote_status(struct git_info *info, git_remote *origin)
{
int error = 0;
git_reference *local_ref, *remote_ref;
if (verbose)
SSRF_INFO("git storage: check remote status\n");
if (git_branch_lookup(&local_ref, info->repo, info->branch, GIT_BRANCH_LOCAL)) {
SSRF_INFO("git storage: branch %s is missing in local repo", info->branch);
if (info->is_subsurface_cloud)
return cleanup_local_cache(info);
else
return report_error("Git cache branch %s no longer exists", info->branch);
}
if (git_branch_upstream(&remote_ref, local_ref)) {
/* so there is no upstream branch for our branch; that's a problem.
* let's push our branch */
SSRF_INFO("git storage: branch %s is missing in remote, pushing branch", info->branch);
git_strarray refspec;
git_reference_list(&refspec, info->repo);
git_push_options opts = GIT_PUSH_OPTIONS_INIT;
opts.callbacks.transfer_progress = &transfer_progress_cb;
auth_attempt = 0;
if (info->transport == RT_SSH)
opts.callbacks.credentials = credential_ssh_cb;
else if (info->transport == RT_HTTPS)
opts.callbacks.credentials = credential_https_cb;
opts.callbacks.certificate_check = certificate_check_cb;
git_storage_update_progress(translate("gettextFromC", "Store data into cloud storage"));
error = git_remote_push(origin, &refspec, &opts);
} else {
error = try_to_update(info, origin, local_ref, remote_ref);
git_reference_free(remote_ref);
}
git_reference_free(local_ref);
git_remote_sync_successful = (error == 0);
return error;
}
/* this is (so far) only used by the git storage tests to remove a remote branch
* it will print out errors, but not return an error (as this isn't a function that
* we test as part of the tests, it's a helper to not leave loads of dead branches on
* the server)
*/
extern "C" void delete_remote_branch(git_repository *repo, const char *remote, const char *branch)
{
int error;
char *proxy_string;
git_remote *origin;
git_config *conf;
/* set up the config and proxy information in order to connect to the server */
git_repository_config(&conf, repo);
if (getProxyString(&proxy_string)) {
git_config_set_string(conf, "http.proxy", proxy_string);
free(proxy_string);
} else {
git_config_delete_entry(conf, "http.proxy");
}
if (git_remote_lookup(&origin, repo, "origin")) {
SSRF_INFO("git storage: repository '%s' origin lookup failed (%s)", remote, giterr_last() ? giterr_last()->message : "(unspecified)");
return;
}
/* fetch the remote state */
git_fetch_options f_opts = GIT_FETCH_OPTIONS_INIT;
auth_attempt = 0;
f_opts.callbacks.credentials = credential_https_cb;
error = git_remote_fetch(origin, NULL, &f_opts, NULL);
if (error) {
SSRF_INFO("git storage: remote fetch failed (%s)\n", giterr_last() ? giterr_last()->message : "authentication failed");
return;
}
/* delete the remote branch by pushing to ":refs/heads/<branch>" */
git_strarray refspec;
char *branch_ref = format_string(":refs/heads/%s", branch);
refspec.count = 1;
refspec.strings = &branch_ref;
git_push_options p_opts = GIT_PUSH_OPTIONS_INIT;
auth_attempt = 0;
p_opts.callbacks.credentials = credential_https_cb;
error = git_remote_push(origin, &refspec, &p_opts);
free(branch_ref);
if (error) {
SSRF_INFO("git storage: unable to delete branch '%s'", branch);
SSRF_INFO("git storage: error was (%s)\n", giterr_last() ? giterr_last()->message : "(unspecified)");
}
git_remote_free(origin);
return;
}
extern "C" int sync_with_remote(struct git_info *info)
{
int error;
git_remote *origin;
char *proxy_string;
git_config *conf;
if (git_local_only) {
if (verbose)
SSRF_INFO("git storage: don't sync with remote - read from cache only\n");
return 0;
}
if (verbose)
SSRF_INFO("git storage: sync with remote %s[%s]\n", info->url, info->branch);
git_storage_update_progress(translate("gettextFromC", "Sync with cloud storage"));
git_repository_config(&conf, info->repo);
if (info->transport == RT_HTTPS && getProxyString(&proxy_string)) {
if (verbose)
SSRF_INFO("git storage: set proxy to \"%s\"\n", proxy_string);
git_config_set_string(conf, "http.proxy", proxy_string);
free(proxy_string);
} else {
if (verbose)
SSRF_INFO("git storage: delete proxy setting\n");
git_config_delete_entry(conf, "http.proxy");
}
/*
* NOTE! Remote errors are reported, but are nonfatal:
* we still successfully return the local repository.
*/
error = git_remote_lookup(&origin, info->repo, "origin");
if (error) {
const char *msg = giterr_last()->message;
SSRF_INFO("git storage: repo %s origin lookup failed with: %s", info->url, msg);
if (!info->is_subsurface_cloud)
report_error("Repository '%s' origin lookup failed (%s)", info->url, msg);
return 0;
}
// we know that we already checked for the cloud server, but to give a decent warning message
// here in case none of them are reachable, let's check one more time
if (info->is_subsurface_cloud && !canReachCloudServer(info)) {
// this is not an error, just a warning message, so return 0
SSRF_INFO("git storage: cannot connect to remote server");
report_error("Cannot connect to cloud server, working with local copy");
git_storage_update_progress(translate("gettextFromC", "Can't reach cloud server, working with local data"));
return 0;
}
if (verbose)
SSRF_INFO("git storage: fetch remote %s\n", git_remote_url(origin));
git_fetch_options opts = GIT_FETCH_OPTIONS_INIT;
opts.callbacks.transfer_progress = &transfer_progress_cb;
auth_attempt = 0;
if (info->transport == RT_SSH)
opts.callbacks.credentials = credential_ssh_cb;
else if (info->transport == RT_HTTPS)
opts.callbacks.credentials = credential_https_cb;
opts.callbacks.certificate_check = certificate_check_cb;
git_storage_update_progress(translate("gettextFromC", "Successful cloud connection, fetch remote"));
error = git_remote_fetch(origin, NULL, &opts, NULL);
// NOTE! A fetch error is not fatal, we just report it
if (error) {
if (info->is_subsurface_cloud)
report_error("Cannot sync with cloud server, working with offline copy");
else
report_error("Unable to fetch remote '%s'", info->url);
// If we returned GIT_EUSER during authentication, giterr_last() returns NULL
SSRF_INFO("git storage: remote fetch failed (%s)\n", giterr_last() ? giterr_last()->message : "authentication failed");
// Since we failed to sync with online repository, enter offline mode
git_local_only = true;
error = 0;
} else {
error = check_remote_status(info, origin);
}
git_remote_free(origin);
git_storage_update_progress(translate("gettextFromC", "Done syncing with cloud storage"));
return error;
}
static bool update_local_repo(struct git_info *info)
{
git_reference *head;
/* Check the HEAD being the right branch */
if (!git_repository_head(&head, info->repo)) {
const char *name;
if (!git_branch_name(&name, head)) {
if (strcmp(name, info->branch)) {
char *branchref = format_string("refs/heads/%s", info->branch);
SSRF_INFO("git storage: setting cache branch from '%s' to '%s'", name, info->branch);
git_repository_set_head(info->repo, branchref);
free(branchref);
}
}
git_reference_free(head);
}
/* make sure we have the correct origin - the cloud server URL could have changed */
if (git_remote_set_url(info->repo, "origin", info->url)) {
SSRF_INFO("git storage: failed to update origin to '%s'", info->url);
return false;
}
if (!git_local_only)
sync_with_remote(info);
return true;
}
static int repository_create_cb(git_repository **out, const char *path, int bare, void *)
{
char *proxy_string;
git_config *conf;
int ret = git_repository_init(out, path, bare);
if (ret != 0) {
if (verbose)
SSRF_INFO("git storage: initializing git repository failed\n");
return ret;
}
git_repository_config(&conf, *out);
if (getProxyString(&proxy_string)) {
if (verbose)
SSRF_INFO("git storage: set proxy to \"%s\"\n", proxy_string);
git_config_set_string(conf, "http.proxy", proxy_string);
free(proxy_string);
} else {
if (verbose)
SSRF_INFO("git storage: delete proxy setting\n");
git_config_delete_entry(conf, "http.proxy");
}
return ret;
}
/* this should correctly initialize both the local and remote
* repository for the Subsurface cloud storage */
static bool create_and_push_remote(struct git_info *info)
{
git_config *conf;
char *variable_name, *head;
if (verbose)
SSRF_INFO("git storage: create and push remote\n");
/* first make sure the directory for the local cache exists */
subsurface_mkdir(info->localdir);
head = format_string("refs/heads/%s", info->branch);
/* set up the origin to point to our remote */
git_repository_init_options init_opts = GIT_REPOSITORY_INIT_OPTIONS_INIT;
init_opts.origin_url = info->url;
init_opts.initial_head = head;
/* now initialize the repository with */
git_repository_init_ext(&info->repo, info->localdir, &init_opts);
/* create a config so we can set the remote tracking branch */
git_repository_config(&conf, info->repo);
variable_name = format_string("branch.%s.remote", info->branch);
git_config_set_string(conf, variable_name, "origin");
free(variable_name);
variable_name = format_string("branch.%s.merge", info->branch);
git_config_set_string(conf, variable_name, head);
free(head);
free(variable_name);
/* finally create an empty commit and push it to the remote */
if (do_git_save(info, false, true))
return false;
return true;
}
static bool create_local_repo(struct git_info *info)
{
int error;
git_clone_options opts = GIT_CLONE_OPTIONS_INIT;
if (verbose)
SSRF_INFO("git storage: create_local_repo\n");
auth_attempt = 0;
opts.fetch_opts.callbacks.transfer_progress = &transfer_progress_cb;
if (info->transport == RT_SSH)
opts.fetch_opts.callbacks.credentials = credential_ssh_cb;
else if (info->transport == RT_HTTPS)
opts.fetch_opts.callbacks.credentials = credential_https_cb;
opts.repository_cb = repository_create_cb;
opts.fetch_opts.callbacks.certificate_check = certificate_check_cb;
opts.checkout_branch = info->branch;
if (info->is_subsurface_cloud && !canReachCloudServer(info)) {
SSRF_INFO("git storage: cannot reach remote server");
return false;
}
if (verbose > 1)
SSRF_INFO("git storage: calling git_clone()\n");
error = git_clone(&info->repo, info->url, info->localdir, &opts);
if (verbose > 1)
SSRF_INFO("git storage: returned from git_clone() with return value %d\n", error);
if (error) {
SSRF_INFO("git storage: clone of %s failed", info->url);
const char *msg = "";
if (giterr_last()) {
msg = giterr_last()->message;
SSRF_INFO("git storage: error message was %s\n", msg);
} else {
SSRF_INFO("git storage: giterr_last() is null\n");
}
char *pattern = format_string("reference 'refs/remotes/origin/%s' not found", info->branch);
// it seems that we sometimes get 'Reference' and sometimes 'reference'
if (includes_string_caseinsensitive(msg, pattern)) {
/* we're trying to open the remote branch that corresponds
* to our cloud storage and the branch doesn't exist.
* So we need to create the branch and push it to the remote */
if (verbose)
SSRF_INFO("git storage: remote repo didn't include our branch\n");
if (create_and_push_remote(info))
error = 0;
#if !defined(DEBUG) && !defined(SUBSURFACE_MOBILE)
} else if (info->is_subsurface_cloud) {
report_error("%s", translate("gettextFromC", "Error connecting to Subsurface cloud storage"));
#endif
} else {
report_error(translate("gettextFromC", "git clone of %s failed (%s)"), info->url, msg);
}
free(pattern);
}
return !error;
}
static enum remote_transport url_to_remote_transport(const char *remote)
{
/* figure out the remote transport */
if (strncmp(remote, "ssh://", 6) == 0)
return RT_SSH;
else if (strncmp(remote, "https://", 8) == 0)
return RT_HTTPS;
else
return RT_OTHER;
}
static bool get_remote_repo(struct git_info *info)
{
struct stat st;
if (verbose > 1) {
SSRF_INFO("git storage: accessing %s\n", info->url);
}
git_storage_update_progress(translate("gettextFromC", "Synchronising data file"));
/* Do we already have a local cache? */
if (!subsurface_stat(info->localdir, &st)) {
int error;
if (verbose)
SSRF_INFO("git storage: update local repo\n");
error = git_repository_open(&info->repo, info->localdir);
if (error) {
const char *msg = giterr_last()->message;
SSRF_INFO("git storage: unable to open local cache at %s: %s", info->localdir, msg);
if (info->is_subsurface_cloud)
(void)cleanup_local_cache(info);
else
report_error("Unable to open git cache repository at %s: %s", info->localdir, msg);
return false;
}
return update_local_repo(info);
} else {
/* We have no local cache yet.
* Take us temporarly online to create a local and
* remote cloud repo.
*/
bool ret;
bool glo = git_local_only;
git_local_only = false;
ret = create_local_repo(info);
git_local_only = glo;
if (ret)
git_remote_sync_successful = true;
return ret;
}
/* all normal cases are handled above */
return false;
}
/*
* Remove the user name from the url if it exists, and
* save it in 'info->username'.
*/
static void extract_username(struct git_info *info, char *url)
{
char c;
char *p = url;
while ((c = *p++) >= 'a' && c <= 'z')
/* nothing */;
if (c != ':')
return;
if (*p++ != '/' || *p++ != '/')
return;
/*
* Ok, we found "[a-z]*://" and we think we have a real
* "remote git" format. The "file://" case was handled
* in the calling function.
*/
info->transport = url_to_remote_transport(url);
char *at = strchr(p, '@');
if (!at)
return;
/* was this the @ that denotes an account? that means it was before the
* first '/' after the protocol:// - so let's find a '/' after that and compare */
char *slash = strchr(p, '/');
if (!slash || at > slash)
return;
/* grab the part between "protocol://" and "@" as encoded email address
* (that's our username) and move the rest of the URL forward, remembering
* to copy the closing NUL as well */
info->username = strndup(p, at - p);
memmove(p, at + 1, strlen(at + 1) + 1);
/*
* Ugly, ugly. Parsing the remote repo user name also sets
* it in the preferences. We should do this somewhere else!
*/
prefs.cloud_storage_email_encoded = strdup(info->username);
}
extern "C" void cleanup_git_info(struct git_info *info)
{
if (info->repo)
git_repository_free(info->repo);
free((void *)info->url);
free((void *)info->branch);
free((void *)info->username);
free((void *)info->localdir);
memset(info, 0, sizeof(*info));
}
/*
* If it's not a git repo, return NULL. Be very conservative.
*
* The recognized formats are
* git://host/repo[branch]
* ssh://host/repo[branch]
* http://host/repo[branch]
* https://host/repo[branch]
* file://repo[branch]
*/
extern "C" bool is_git_repository(const char *filename, struct git_info *info)
{
int flen, blen;
int offset = 1;
char *url, *branch;
/* we are looking at a new potential remote, but we haven't synced with it */
git_remote_sync_successful = false;
memset(info, 0, sizeof(*info));
info->transport = RT_LOCAL;
flen = strlen(filename);
if (!flen || filename[--flen] != ']')
return false;
/*
* Special-case "file://", and treat it as a local
* repository since libgit2 is insanely slow for that.
*/
if (!strncmp(filename, "file://", 7)) {
filename += 7;
flen -= 7;
}
/* Find the matching '[' */
blen = 0;
while (flen && filename[--flen] != '[')
blen++;
/* Ignore slashes at the end of the repo name */
while (flen && filename[flen-1] == '/') {
flen--;
offset++;
}
if (!flen)
return false;
/*
* This is the "point of no return": the name matches
* the git repository name rules, and we will no longer
* return NULL.
*
* We will either return with NULL git repo and the
* branch pointer will have the _whole_ filename in it,
* or we will return a real git repository with the
* branch pointer being filled in with just the branch
* name.
*
* The actual git reading/writing routines can use this
* to generate proper error messages.
*/
url = format_string("%.*s", flen, filename);
branch = format_string("%.*s", blen, filename + flen + offset);
/* Extract the username from the url string */
extract_username(info, url);
info->url = url;
info->branch = branch;
/*
* We now create the SHA1 hash of the whole thing,
* including the branch name. That will be our unique
* local repository name.
*
* NOTE! We will create a local repository per branch,
* because
*
* (a) libgit2 remote tracking branch support seems to
* be a bit lacking
* (b) we'll actually check the branch out so that we
* can do merges etc too.
*
* so even if you have a single remote git repo with
* multiple branches for different people, the local
* caches will sadly force that to split into multiple
* individual repositories.
*/
switch (info->transport) {
case RT_LOCAL:
info->localdir = strdup(url);
break;
default:
info->localdir = get_local_dir(info->url, info->branch);
break;
}
/*
* Remember if the current git storage we are working on is our
* cloud storage.
*
* This is used to create more user friendly error message and warnings.
*/
info->is_subsurface_cloud = (strstr(info->url, prefs.cloud_base_url) != NULL);
return true;
}
extern "C" bool open_git_repository(struct git_info *info)
{
/*
* If the repository is local, just open it. There's nothing
* else to do.
*/
if (info->transport == RT_LOCAL) {
const char *url = info->localdir;
if (git_repository_open(&info->repo, url)) {
if (verbose)
SSRF_INFO("git storage: loc %s couldn't be opened (%s)\n", url, giterr_last()->message);
return false;
}
return true;
}
/* if we are planning to access the server, make sure it's available and try to
* pick one of the alternative servers if necessary */
if (info->is_subsurface_cloud && !git_local_only) {
// since we know that this is Subsurface cloud storage, we don't have to
// worry about the local directory name changing if we end up with a different
// cloud_base_url... the algorithm normalizes those URLs
(void)canReachCloudServer(info);
}
return get_remote_repo(info);
}
extern "C" int git_create_local_repo(const char *filename)
{
git_repository *repo;
char *path = strdup(filename);
char *branch = strchr(path, '[');
if (branch)
*branch = '\0';
int ret = git_repository_init(&repo, path, false);
free(path);
if (ret != 0)
(void)report_error("Create local repo failed with error code %d", ret);
git_repository_free(repo);
return ret;
}
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