import: rename 'poll-dck' to 'pull-dkr'

I figure "pull-dck" is not a good name, given that one could certainly
read the verb in a way that might be funny for 16year-olds. ;-)

Also, don't hardcode the index URL to use, make it runtime and configure
time configurable instead.

1 files changed, 1177 insertions, 0 deletions

diff --git a/src/import/import-dkr.c b/src/import/import-dkr.c
new file mode 100644
index 0000000000..e2910f940f
--- /dev/null
+++ b/src/import/import-dkr.c
@@ -0,0 +1,1177 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <curl/curl.h>
+#include <sys/prctl.h>
+
+#include "hashmap.h"
+#include "set.h"
+#include "json.h"
+#include "strv.h"
+#include "curl-util.h"
+#include "import-dkr.h"
+#include "btrfs-util.h"
+#include "aufs-util.h"
+#include "utf8.h"
+
+/* TODO:
+  - convert json bits
+  - man page
+  - fall back to btrfs loop pool device
+*/
+
+typedef struct DkrImportJob DkrImportJob;
+typedef struct DkrImportName DkrImportName;
+
+typedef enum DkrImportJobType {
+        DKR_IMPORT_JOB_IMAGES,
+        DKR_IMPORT_JOB_TAGS,
+        DKR_IMPORT_JOB_ANCESTRY,
+        DKR_IMPORT_JOB_JSON,
+        DKR_IMPORT_JOB_LAYER,
+} DkrImportJobType;
+
+struct DkrImportJob {
+        DkrImport *import;
+        DkrImportJobType type;
+        bool done;
+
+        char *url;
+
+        Set *needed_by; /* DkrImport Name objects */
+
+        CURL *curl;
+        struct curl_slist *request_header;
+        void *payload;
+        size_t payload_size;
+
+        char *response_token;
+        char **response_registries;
+
+        char *temp_path;
+        char *final_path;
+
+        pid_t tar_pid;
+        FILE *tar_stream;
+};
+
+struct DkrImportName {
+        DkrImport *import;
+
+        char *index_url;
+        char *name;
+        char *tag;
+        char *id;
+        char *local;
+
+        DkrImportJob *job_images, *job_tags, *job_ancestry, *job_json, *job_layer;
+
+        char **ancestry;
+        unsigned current_ancestry;
+
+        bool force_local;
+};
+
+struct DkrImport {
+        sd_event *event;
+        CurlGlue *glue;
+
+        Hashmap *names;
+        Hashmap *jobs;
+
+        dkr_import_on_finished on_finished;
+        void *userdata;
+};
+
+#define PROTOCOL_PREFIX "https://"
+
+#define HEADER_TOKEN "X-Do" /* the HTTP header for the auth token */ "cker-Token:"
+#define HEADER_REGISTRY "X-Do" /*the HTTP header for the registry */ "cker-Endpoints:"
+
+#define PAYLOAD_MAX (16*1024*1024)
+#define LAYERS_MAX 2048
+
+static int dkr_import_name_add_job(DkrImportName *name, DkrImportJobType type, const char *url, DkrImportJob **ret);
+
+static DkrImportJob *dkr_import_job_unref(DkrImportJob *job) {
+        if (!job)
+                return NULL;
+
+        if (job->import)
+                curl_glue_remove_and_free(job->import->glue, job->curl);
+        curl_slist_free_all(job->request_header);
+
+        if (job->tar_stream)
+                fclose(job->tar_stream);
+
+        free(job->final_path);
+
+        if (job->temp_path) {
+                btrfs_subvol_remove(job->temp_path);
+                free(job->temp_path);
+        }
+
+        set_free(job->needed_by);
+
+        if (job->tar_pid > 0)
+                kill(job->tar_pid, SIGTERM);
+
+        free(job->url);
+        free(job->payload);
+        free(job->response_token);
+        strv_free(job->response_registries);
+
+        free(job);
+
+        return NULL;
+}
+
+static DkrImportName *dkr_import_name_unref(DkrImportName *name) {
+        if (!name)
+                return NULL;
+
+        if (name->job_images)
+                set_remove(name->job_images->needed_by, name);
+
+        if (name->job_tags)
+                set_remove(name->job_tags->needed_by, name);
+
+        if (name->job_ancestry)
+                set_remove(name->job_ancestry->needed_by, name);
+
+        if (name->job_json)
+                set_remove(name->job_json->needed_by, name);
+
+        if (name->job_layer)
+                set_remove(name->job_layer->needed_by, name);
+
+        free(name->index_url);
+        free(name->name);
+        free(name->id);
+        free(name->tag);
+        free(name->local);
+
+        strv_free(name->ancestry);
+        free(name);
+
+        return NULL;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DkrImportJob*, dkr_import_job_unref);
+DEFINE_TRIVIAL_CLEANUP_FUNC(DkrImportName*, dkr_import_name_unref);
+
+static void dkr_import_finish(DkrImport *import, int error) {
+        assert(import);
+
+        if (import->on_finished)
+                import->on_finished(import, error, import->userdata);
+        else
+                sd_event_exit(import->event, error);
+}
+
+static int parse_id(const void *payload, size_t size, char **ret) {
+        _cleanup_free_ char *buf = NULL, *id = NULL, *other = NULL;
+        union json_value v = {};
+        void *json_state = NULL;
+        const char *p;
+        int t;
+
+        assert(payload);
+        assert(ret);
+
+        if (size <= 0)
+                return -EBADMSG;
+
+        if (memchr(payload, 0, size))
+                return -EBADMSG;
+
+        buf = strndup(payload, size);
+        if (!buf)
+                return -ENOMEM;
+
+        p = buf;
+        t = json_tokenize(&p, &id, &v, &json_state, NULL);
+        if (t < 0)
+                return t;
+        if (t != JSON_STRING)
+                return -EBADMSG;
+
+        t = json_tokenize(&p, &other, &v, &json_state, NULL);
+        if (t < 0)
+                return t;
+        if (t != JSON_END)
+                return -EBADMSG;
+
+        if (!dkr_id_is_valid(id))
+                return -EBADMSG;
+
+        *ret = id;
+        id = NULL;
+
+        return 0;
+}
+
+static int parse_ancestry(const void *payload, size_t size, char ***ret) {
+        _cleanup_free_ char *buf = NULL;
+        void *json_state = NULL;
+        const char *p;
+        enum {
+                STATE_BEGIN,
+                STATE_ITEM,
+                STATE_COMMA,
+                STATE_END,
+        } state = STATE_BEGIN;
+        _cleanup_strv_free_ char **l = NULL;
+        size_t n = 0, allocated = 0;
+
+        if (size <= 0)
+                return -EBADMSG;
+
+        if (memchr(payload, 0, size))
+                return -EBADMSG;
+
+        buf = strndup(payload, size);
+        if (!buf)
+                return -ENOMEM;
+
+        p = buf;
+        for (;;) {
+                _cleanup_free_ char *str;
+                union json_value v = {};
+                int t;
+
+                t = json_tokenize(&p, &str, &v, &json_state, NULL);
+                if (t < 0)
+                        return t;
+
+                switch (state) {
+
+                case STATE_BEGIN:
+                        if (t == JSON_ARRAY_OPEN)
+                                state = STATE_ITEM;
+                        else
+                                return -EBADMSG;
+
+                        break;
+
+                case STATE_ITEM:
+                        if (t == JSON_STRING) {
+                                if (!dkr_id_is_valid(str))
+                                        return -EBADMSG;
+
+                                if (n+1 > LAYERS_MAX)
+                                        return -EFBIG;
+
+                                if (!GREEDY_REALLOC(l, allocated, n + 2))
+                                        return -ENOMEM;
+
+                                l[n++] = str;
+                                str = NULL;
+                                l[n] = NULL;
+
+                                state = STATE_COMMA;
+
+                        } else if (t == JSON_ARRAY_CLOSE)
+                                state = STATE_END;
+                        else
+                                return -EBADMSG;
+
+                        break;
+
+                case STATE_COMMA:
+                        if (t == JSON_COMMA)
+                                state = STATE_ITEM;
+                        else if (t == JSON_ARRAY_CLOSE)
+                                state = STATE_END;
+                        else
+                                return -EBADMSG;
+                        break;
+
+                case STATE_END:
+                        if (t == JSON_END) {
+
+                                if (strv_isempty(l))
+                                        return -EBADMSG;
+
+                                if (!strv_is_uniq(l))
+                                        return -EBADMSG;
+
+                                l = strv_reverse(l);
+
+                                *ret = l;
+                                l = NULL;
+                                return 0;
+                        } else
+                                return -EBADMSG;
+                }
+
+        }
+}
+
+static const char *dkr_import_name_current_layer(DkrImportName *name) {
+        assert(name);
+
+        if (strv_isempty(name->ancestry))
+                return NULL;
+
+        return name->ancestry[name->current_ancestry];
+}
+
+static const char *dkr_import_name_current_base_layer(DkrImportName *name) {
+        assert(name);
+
+        if (strv_isempty(name->ancestry))
+                return NULL;
+
+        if (name->current_ancestry <= 0)
+                return NULL;
+
+        return name->ancestry[name->current_ancestry-1];
+}
+
+static char** dkr_import_name_get_registries(DkrImportName *name) {
+        assert(name);
+
+        if (!name->job_images)
+                return NULL;
+
+        if (!name->job_images->done)
+                return NULL;
+
+        if (strv_isempty(name->job_images->response_registries))
+                return NULL;
+
+        return name->job_images->response_registries;
+}
+
+static const char*dkr_import_name_get_token(DkrImportName *name) {
+        assert(name);
+
+        if (!name->job_images)
+                return NULL;
+
+        if (!name->job_images->done)
+                return NULL;
+
+        return name->job_images->response_token;
+}
+
+static void dkr_import_name_maybe_finish(DkrImportName *name) {
+        int r;
+
+        assert(name);
+
+        if (!name->job_images || !name->job_images->done)
+                return;
+
+        if (!name->job_ancestry || !name->job_ancestry->done)
+                return;
+
+        if (!name->job_json || !name->job_json->done)
+                return;
+
+        if (name->job_layer && !name->job_json->done)
+                return;
+
+        if (dkr_import_name_current_layer(name))
+                return;
+
+        if (name->local) {
+                const char *p, *q;
+
+                assert(name->id);
+
+                p = strappenda("/var/lib/container/", name->local);
+                q = strappenda("/var/lib/container/.dkr-", name->id);
+
+                if (name->force_local) {
+                        (void) btrfs_subvol_remove(p);
+                        (void) rm_rf(p, false, true, false);
+                }
+
+                r = btrfs_subvol_snapshot(q, p, false, false);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to snapshot final image: %m");
+                        dkr_import_finish(name->import, r);
+                        return;
+                }
+
+                log_info("Created new image %s.", p);
+        }
+
+        dkr_import_finish(name->import, 0);
+}
+
+static int dkr_import_job_run_tar(DkrImportJob *job) {
+        _cleanup_close_pair_ int pipefd[2] = { -1, -1 };
+        bool gzip;
+
+        assert(job);
+
+        /* A stream to run tar on? */
+        if (!job->temp_path)
+                return 0;
+
+        if (job->tar_stream)
+                return 0;
+
+        /* Maybe fork off tar, if we have enough to figure out that
+         * something is gzip compressed or not */
+
+        if (job->payload_size < 2)
+                return 0;
+
+        /* Detect gzip signature */
+        gzip = ((uint8_t*) job->payload)[0] == 0x1f &&
+               ((uint8_t*) job->payload)[1] == 0x8b;
+
+        assert(!job->tar_stream);
+        assert(job->tar_pid <= 0);
+
+        if (pipe2(pipefd, O_CLOEXEC) < 0)
+                return log_error_errno(errno, "Failed to create pipe for tar: %m");
+
+        job->tar_pid = fork();
+        if (job->tar_pid < 0)
+                return log_error_errno(errno, "Failed to fork off tar: %m");
+        if (job->tar_pid == 0) {
+                int null_fd;
+
+                reset_all_signal_handlers();
+                reset_signal_mask();
+                assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
+
+                pipefd[1] = safe_close(pipefd[1]);
+
+                if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
+                        log_error_errno(errno, "Failed to dup2() fd: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                if (pipefd[0] != STDIN_FILENO)
+                        safe_close(pipefd[0]);
+                if (pipefd[1] != STDIN_FILENO)
+                        safe_close(pipefd[1]);
+
+                null_fd = open("/dev/null", O_WRONLY|O_NOCTTY);
+                if (null_fd < 0) {
+                        log_error_errno(errno, "Failed to open /dev/null: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) {
+                        log_error_errno(errno, "Failed to dup2() fd: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                if (null_fd != STDOUT_FILENO)
+                        safe_close(null_fd);
+
+                execlp("tar", "tar", "-C", job->temp_path, gzip ? "-xz" : "-x", NULL);
+                _exit(EXIT_FAILURE);
+        }
+
+        pipefd[0] = safe_close(pipefd[0]);
+
+        job->tar_stream = fdopen(pipefd[1], "w");
+        if (!job->tar_stream)
+                return log_error_errno(errno, "Failed to allocate tar stream: %m");
+
+        pipefd[1] = -1;
+
+        if (fwrite(job->payload, 1, job->payload_size, job->tar_stream) != job->payload_size)
+                return log_error_errno(errno, "Couldn't write payload: %m");
+
+        free(job->payload);
+        job->payload = NULL;
+        job->payload_size = 0;
+
+        return 0;
+}
+
+static int dkr_import_name_pull_layer(DkrImportName *name) {
+        _cleanup_free_ char *path = NULL, *temp = NULL;
+        const char *url, *layer = NULL, *base = NULL;
+        char **rg;
+        int r;
+
+        assert(name);
+
+        if (name->job_layer) {
+                set_remove(name->job_layer->needed_by, name);
+                name->job_layer = NULL;
+        }
+
+        for (;;) {
+                layer = dkr_import_name_current_layer(name);
+                if (!layer) {
+                        dkr_import_name_maybe_finish(name);
+                        return 0;
+                }
+
+                path = strjoin("/var/lib/container/.dkr-", layer, NULL);
+                if (!path)
+                        return log_oom();
+
+                if (laccess(path, F_OK) < 0) {
+                        if (errno == ENOENT)
+                                break;
+
+                        return log_error_errno(errno, "Failed to check for container: %m");
+                }
+
+                log_info("Layer %s already exists, skipping.", layer);
+
+                name->current_ancestry++;
+
+                free(path);
+                path = NULL;
+        }
+
+        rg = dkr_import_name_get_registries(name);
+        assert(rg && rg[0]);
+
+        url = strappenda(PROTOCOL_PREFIX, rg[0], "/v1/images/", layer, "/layer");
+        r = dkr_import_name_add_job(name, DKR_IMPORT_JOB_LAYER, url, &name->job_layer);
+        if (r < 0) {
+                log_error_errno(r, "Failed to issue HTTP request: %m");
+                return r;
+        }
+        if (r == 0) /* Already downloading this one? */
+                return 0;
+
+        log_info("Pulling layer %s...", layer);
+
+        r = tempfn_random(path, &temp);
+        if (r < 0)
+                return log_oom();
+
+        base = dkr_import_name_current_base_layer(name);
+        if (base) {
+                const char *base_path;
+
+                base_path = strappend("/var/lib/container/.dkr-", base);
+                r = btrfs_subvol_snapshot(base_path, temp, false, true);
+        } else
+                r = btrfs_subvol_make(temp);
+
+        if (r < 0)
+                return log_error_errno(r, "Failed to make btrfs subvolume %s", temp);
+
+        name->job_layer->final_path = path;
+        name->job_layer->temp_path = temp;
+        path = temp = NULL;
+
+        return 0;
+}
+
+static void dkr_import_name_job_finished(DkrImportName *name, DkrImportJob *job) {
+        int r;
+
+        assert(name);
+        assert(job);
+
+        if (name->job_images == job) {
+                const char *url;
+                char **rg;
+
+                assert(!name->job_tags);
+                assert(!name->job_ancestry);
+                assert(!name->job_json);
+                assert(!name->job_layer);
+
+                rg = dkr_import_name_get_registries(name);
+                if (strv_isempty(rg)) {
+                        log_error("Didn't get registry information.");
+                        r = -EBADMSG;
+                        goto fail;
+                }
+
+                log_info("Index lookup succeeded, directed to registry %s.", rg[0]);
+
+                url = strappenda(PROTOCOL_PREFIX, rg[0], "/v1/repositories/", name->name, "/tags/", name->tag);
+
+                r = dkr_import_name_add_job(name, DKR_IMPORT_JOB_TAGS, url, &name->job_tags);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to issue HTTP request: %m");
+                        goto fail;
+                }
+
+        } else if (name->job_tags == job) {
+                const char *url;
+                char *id = NULL, **rg;
+
+                assert(!name->job_ancestry);
+                assert(!name->job_json);
+                assert(!name->job_layer);
+
+                r = parse_id(job->payload, job->payload_size, &id);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to parse JSON id.");
+                        goto fail;
+                }
+
+                free(name->id);
+                name->id = id;
+
+                rg = dkr_import_name_get_registries(name);
+                assert(rg && rg[0]);
+
+                log_info("Tag lookup succeeded, resolved to layer %s.", name->id);
+
+                url = strappenda(PROTOCOL_PREFIX, rg[0], "/v1/images/", name->id, "/ancestry");
+                r = dkr_import_name_add_job(name, DKR_IMPORT_JOB_ANCESTRY, url, &name->job_ancestry);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to issue HTTP request: %m");
+                        goto fail;
+                }
+
+                url = strappenda(PROTOCOL_PREFIX, rg[0], "/v1/images/", name->id, "/json");
+                r = dkr_import_name_add_job(name, DKR_IMPORT_JOB_JSON, url, &name->job_json);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to issue HTTP request: %m");
+                        goto fail;
+                }
+
+        } else if (name->job_ancestry == job) {
+                char **ancestry = NULL, **i;
+                unsigned n;
+
+                r = parse_ancestry(job->payload, job->payload_size, &ancestry);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to parse JSON id.");
+                        goto fail;
+                }
+
+                n = strv_length(ancestry);
+                if (n <= 0 || !streq(ancestry[n-1], name->id)) {
+                        log_error("Ancestry doesn't end in main layer.");
+                        r = -EBADMSG;
+                        goto fail;
+                }
+
+                log_info("Ancestor lookup succeeded, requires layers:\n");
+                STRV_FOREACH(i, ancestry)
+                        log_info("\t%s", *i);
+
+                strv_free(name->ancestry);
+                name->ancestry = ancestry;
+
+                name->current_ancestry = 0;
+                r = dkr_import_name_pull_layer(name);
+                if (r < 0)
+                        goto fail;
+
+        } else if (name->job_json == job) {
+
+                dkr_import_name_maybe_finish(name);
+
+        } else if (name->job_layer == job) {
+
+                name->current_ancestry ++;
+                r = dkr_import_name_pull_layer(name);
+                if (r < 0)
+                        goto fail;
+
+        } else
+                assert_not_reached("Got finished event for unknown curl object");
+
+        return;
+
+fail:
+        dkr_import_finish(name->import, r);
+}
+
+static void dkr_import_curl_on_finished(CurlGlue *g, CURL *curl, CURLcode result) {
+        DkrImportJob *job = NULL;
+        CURLcode code;
+        DkrImportName *n;
+        long status;
+        Iterator i;
+        int r;
+
+        if (curl_easy_getinfo(curl, CURLINFO_PRIVATE, &job) != CURLE_OK)
+                return;
+
+        if (!job)
+                return;
+
+        job->done = true;
+
+        if (result != CURLE_OK) {
+                log_error("Transfer failed: %s", curl_easy_strerror(result));
+                r = -EIO;
+                goto fail;
+        }
+
+        code = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &status);
+        if (code != CURLE_OK) {
+                log_error("Failed to retrieve response code: %s", curl_easy_strerror(code));
+                r = -EIO;
+                goto fail;
+        } else if (status >= 300) {
+                log_error("HTTP request to %s failed with code %li.", job->url, status);
+                r = -EIO;
+                goto fail;
+        } else if (status < 200) {
+                log_error("HTTP request to %s finished with unexpected code %li.", job->url, status);
+                r = -EIO;
+                goto fail;
+        }
+
+        switch (job->type) {
+
+        case DKR_IMPORT_JOB_LAYER: {
+                siginfo_t si;
+
+                if (!job->tar_stream) {
+                        log_error("Downloaded layer too short.");
+                        r = -EIO;
+                        goto fail;
+                }
+
+                fclose(job->tar_stream);
+                job->tar_stream = NULL;
+
+                assert(job->tar_pid > 0);
+
+                r = wait_for_terminate(job->tar_pid, &si);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to wait for tar process: %m");
+                        goto fail;
+                }
+
+                job->tar_pid = 0;
+
+                if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS) {
+                        log_error_errno(r, "tar failed abnormally.");
+                        r = -EIO;
+                        goto fail;
+                }
+
+                r = aufs_resolve(job->temp_path);
+                if (r < 0) {
+                        log_error_errno(r, "Couldn't resolve aufs whiteouts: %m");
+                        goto fail;
+                }
+
+                r = btrfs_subvol_read_only(job->temp_path, true);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to mark snapshot read-only: %m");
+                        goto fail;
+                }
+
+                if (rename(job->temp_path, job->final_path) < 0) {
+                        log_error_errno(r, "Failed to rename snapshot: %m");
+                        goto fail;
+                }
+
+                log_info("Completed writing to layer %s", job->final_path);
+                break;
+        }
+
+        default:
+                ;
+        }
+
+        SET_FOREACH(n, job->needed_by, i)
+                dkr_import_name_job_finished(n, job);
+
+        return;
+
+fail:
+        dkr_import_finish(job->import, r);
+}
+
+static size_t dkr_import_job_write_callback(void *contents, size_t size, size_t nmemb, void *userdata) {
+        DkrImportJob *j = userdata;
+        size_t sz = size * nmemb;
+        char *p;
+        int r;
+
+        assert(contents);
+        assert(j);
+
+        if (j->tar_stream) {
+                size_t l;
+
+                l = fwrite(contents, size, nmemb, j->tar_stream);
+                if (l != nmemb) {
+                        r = -errno;
+                        goto fail;
+                }
+
+                return l;
+        }
+
+        if (j->payload_size + sz > PAYLOAD_MAX) {
+                r = -EFBIG;
+                goto fail;
+        }
+
+        p = realloc(j->payload, j->payload_size + sz);
+        if (!p) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        memcpy(p + j->payload_size, contents, sz);
+        j->payload_size += sz;
+        j->payload = p;
+
+        r = dkr_import_job_run_tar(j);
+        if (r < 0)
+                goto fail;
+
+        return sz;
+
+fail:
+        dkr_import_finish(j->import, r);
+        return 0;
+}
+
+static size_t dkr_import_job_header_callback(void *contents, size_t size, size_t nmemb, void *userdata) {
+        _cleanup_free_ char *registry = NULL;
+        size_t sz = size * nmemb;
+        DkrImportJob *j = userdata;
+        char *token;
+        int r;
+
+        assert(contents);
+        assert(j);
+
+        r = curl_header_strdup(contents, sz, HEADER_TOKEN, &token);
+        if (r < 0) {
+                log_oom();
+                goto fail;
+        }
+        if (r > 0) {
+                free(j->response_token);
+                j->response_token = token;
+        }
+
+        r = curl_header_strdup(contents, sz, HEADER_REGISTRY, &registry);
+        if (r < 0) {
+                log_oom();
+                goto fail;
+        }
+        if (r > 0) {
+                char **l, **i;
+
+                l = strv_split(registry, ",");
+                if (!l) {
+                        r = log_oom();
+                        goto fail;
+                }
+
+                STRV_FOREACH(i, l) {
+                        if (!hostname_is_valid(*i)) {
+                                log_error("Registry hostname is not valid.");
+                                strv_free(l);
+                                r = -EBADMSG;
+                                goto fail;
+                        }
+                }
+
+                strv_free(j->response_registries);
+                j->response_registries = l;
+        }
+
+        return sz;
+
+fail:
+        dkr_import_finish(j->import, r);
+        return 0;
+}
+
+static int dkr_import_name_add_job(DkrImportName *name, DkrImportJobType type, const char *url, DkrImportJob **ret) {
+        _cleanup_(dkr_import_job_unrefp) DkrImportJob *j = NULL;
+        DkrImportJob *f = NULL;
+        const char *t, *token;
+        int r;
+
+        assert(name);
+        assert(url);
+        assert(ret);
+
+        log_info("Getting %s.", url);
+        f = hashmap_get(name->import->jobs, url);
+        if (f) {
+                if (f->type != type)
+                        return -EINVAL;
+
+                r = set_put(f->needed_by, name);
+                if (r < 0)
+                        return r;
+
+                return 0;
+        }
+
+        r = hashmap_ensure_allocated(&name->import->jobs, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        j = new0(DkrImportJob, 1);
+        if (!j)
+                return -ENOMEM;
+
+        j->import = name->import;
+        j->type = type;
+        j->url = strdup(url);
+        if (!j->url)
+                return -ENOMEM;
+
+        r = set_ensure_allocated(&j->needed_by, &trivial_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = curl_glue_make(&j->curl, j->url, j);
+        if (r < 0)
+                return r;
+
+        token = dkr_import_name_get_token(name);
+        if (token)
+                t = strappenda("Authorization: Token ", token);
+        else
+                t = HEADER_TOKEN " true";
+
+        j->request_header = curl_slist_new("Accept: application/json", t, NULL);
+        if (!j->request_header)
+                return -ENOMEM;
+
+        if (curl_easy_setopt(j->curl, CURLOPT_HTTPHEADER, j->request_header) != CURLE_OK)
+                return -EIO;
+
+        if (curl_easy_setopt(j->curl, CURLOPT_WRITEFUNCTION, dkr_import_job_write_callback) != CURLE_OK)
+                return -EIO;
+
+        if (curl_easy_setopt(j->curl, CURLOPT_WRITEDATA, j) != CURLE_OK)
+                return -EIO;
+
+        if (curl_easy_setopt(j->curl, CURLOPT_HEADERFUNCTION, dkr_import_job_header_callback) != CURLE_OK)
+                return -EIO;
+
+        if (curl_easy_setopt(j->curl, CURLOPT_HEADERDATA, j) != CURLE_OK)
+                return -EIO;
+
+        r = curl_glue_add(name->import->glue, j->curl);
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(name->import->jobs, j->url, j);
+        if (r < 0)
+                return r;
+
+        r = set_put(j->needed_by, name);
+        if (r < 0) {
+                hashmap_remove(name->import->jobs, url);
+                return r;
+        }
+
+        *ret = j;
+        j = NULL;
+
+        return 1;
+}
+
+static int dkr_import_name_begin(DkrImportName *name) {
+        const char *url;
+
+        assert(name);
+        assert(!name->job_images);
+
+        url = strappenda(name->index_url, "/v1/repositories/", name->name, "/images");
+
+        return dkr_import_name_add_job(name, DKR_IMPORT_JOB_IMAGES, url, &name->job_images);
+}
+
+int dkr_import_new(DkrImport **import, sd_event *event, dkr_import_on_finished on_finished, void *userdata) {
+        _cleanup_(dkr_import_unrefp) DkrImport *i = NULL;
+        int r;
+
+        assert(import);
+
+        i = new0(DkrImport, 1);
+        if (!i)
+                return -ENOMEM;
+
+        i->on_finished = on_finished;
+        i->userdata = userdata;
+
+        if (event)
+                i->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&i->event);
+                if (r < 0)
+                        return r;
+        }
+
+        r = curl_glue_new(&i->glue, i->event);
+        if (r < 0)
+                return r;
+
+        i->glue->on_finished = dkr_import_curl_on_finished;
+        i->glue->userdata = i;
+
+        *import = i;
+        i = NULL;
+
+        return 0;
+}
+
+DkrImport* dkr_import_unref(DkrImport *import) {
+        DkrImportName *n;
+        DkrImportJob *j;
+
+        if (!import)
+                return NULL;
+
+        while ((n = hashmap_steal_first(import->names)))
+               dkr_import_name_unref(n);
+        hashmap_free(import->names);
+
+        while ((j = hashmap_steal_first(import->jobs)))
+                dkr_import_job_unref(j);
+        hashmap_free(import->jobs);
+
+        curl_glue_unref(import->glue);
+        sd_event_unref(import->event);
+
+        free(import);
+
+        return NULL;
+}
+
+int dkr_import_cancel(DkrImport *import, const char *name) {
+        DkrImportName *n;
+
+        assert(import);
+        assert(name);
+
+        n = hashmap_remove(import->names, name);
+        if (!n)
+                return 0;
+
+        dkr_import_name_unref(n);
+        return 1;
+}
+
+int dkr_import_pull(DkrImport *import, const char *index_url, const char *name, const char *tag, const char *local, bool force_local) {
+        _cleanup_(dkr_import_name_unrefp) DkrImportName *n = NULL;
+        char *e;
+        int r;
+
+        assert(import);
+        assert(dkr_url_is_valid(index_url));
+        assert(dkr_name_is_valid(name));
+        assert(dkr_tag_is_valid(tag));
+        assert(!local || machine_name_is_valid(local));
+
+        if (hashmap_get(import->names, name))
+                return -EEXIST;
+
+        r = hashmap_ensure_allocated(&import->names, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        n = new0(DkrImportName, 1);
+        if (!n)
+                return -ENOMEM;
+
+        n->import = import;
+
+        n->index_url = strdup(index_url);
+        if (!n->index_url)
+                return -ENOMEM;
+        e = endswith(n->index_url, "/");
+        if (e)
+                *e = NULL;
+
+        n->name = strdup(name);
+        if (!n->name)
+                return -ENOMEM;
+
+        n->tag = strdup(tag);
+        if (!n->tag)
+                return -ENOMEM;
+
+        if (local) {
+                n->local = strdup(local);
+                if (!n->local)
+                        return -ENOMEM;
+                n->force_local = force_local;
+        }
+
+        r = hashmap_put(import->names, name, n);
+        if (r < 0)
+                return r;
+
+        r = dkr_import_name_begin(n);
+        if (r < 0) {
+                dkr_import_cancel(import, n->name);
+                n = NULL;
+                return r;
+        }
+
+        n = NULL;
+
+        return 0;
+}
+
+bool dkr_name_is_valid(const char *name) {
+        const char *slash, *p;
+
+        if (isempty(name))
+                return false;
+
+        slash = strchr(name, '/');
+        if (!slash)
+                return false;
+
+        if (!filename_is_valid(slash + 1))
+                return false;
+
+        p = strndupa(name, slash - name);
+        if (!filename_is_valid(p))
+                return false;
+
+        return true;
+}
+
+bool dkr_id_is_valid(const char *id) {
+
+        if (!filename_is_valid(id))
+                return false;
+
+        if (!in_charset(id, "0123456789abcdef"))
+                return false;
+
+        return true;
+}
+
+bool dkr_url_is_valid(const char *url) {
+
+        if (!startswith(url, "http://") &&
+            !startswith(url, "https://"))
+                return false;
+
+        return ascii_is_valid(url);
+}