Fork of Original Code Base: anongit.freedesktop.org/systemd

This is the initial fork of the code base from freedsktop.org.
The code is provided here as a reference of the initial starting
point and for possible future checkouts after a large portion
of this code is removed.

Merge git://anongit.freedesktop.org/systemd/systemd

1 files changed, 904 insertions, 0 deletions

diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
new file mode 100644
index 0000000000..36cce73550
--- /dev/null
+++ b/src/shared/logs-show.c
@@ -0,0 +1,904 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 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 <time.h>
+#include <assert.h>
+#include <errno.h>
+#include <sys/poll.h>
+#include <string.h>
+
+#include "logs-show.h"
+#include "log.h"
+#include "util.h"
+#include "utf8.h"
+#include "hashmap.h"
+
+#define PRINT_THRESHOLD 128
+#define JSON_THRESHOLD 4096
+
+static int parse_field(const void *data, size_t length, const char *field, char **target, size_t *target_size) {
+        size_t fl, nl;
+        void *buf;
+
+        assert(data);
+        assert(field);
+        assert(target);
+        assert(target_size);
+
+        fl = strlen(field);
+        if (length < fl)
+                return 0;
+
+        if (memcmp(data, field, fl))
+                return 0;
+
+        nl = length - fl;
+        buf = malloc(nl+1);
+        if (!buf)
+                return log_oom();
+
+        memcpy(buf, (const char*) data + fl, nl);
+        ((char*)buf)[nl] = 0;
+
+        free(*target);
+        *target = buf;
+        *target_size = nl;
+
+        return 1;
+}
+
+static bool shall_print(const char *p, size_t l, OutputFlags flags) {
+        assert(p);
+
+        if (flags & OUTPUT_SHOW_ALL)
+                return true;
+
+        if (l > PRINT_THRESHOLD)
+                return false;
+
+        if (!utf8_is_printable_n(p, l))
+                return false;
+
+        return true;
+}
+
+static int output_short(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        int r;
+        const void *data;
+        size_t length;
+        size_t n = 0;
+        _cleanup_free_ char *hostname = NULL, *identifier = NULL, *comm = NULL, *pid = NULL, *fake_pid = NULL, *message = NULL, *realtime = NULL, *monotonic = NULL, *priority = NULL;
+        size_t hostname_len = 0, identifier_len = 0, comm_len = 0, pid_len = 0, fake_pid_len = 0, message_len = 0, realtime_len = 0, monotonic_len = 0, priority_len = 0;
+        int p = LOG_INFO;
+        const char *color_on = "", *color_off = "";
+
+        assert(f);
+        assert(j);
+
+        SD_JOURNAL_FOREACH_DATA(j, data, length) {
+
+                r = parse_field(data, length, "PRIORITY=", &priority, &priority_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "_HOSTNAME=", &hostname, &hostname_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "SYSLOG_IDENTIFIER=", &identifier, &identifier_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "_COMM=", &comm, &comm_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "_PID=", &pid, &pid_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "SYSLOG_PID=", &fake_pid, &fake_pid_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "_SOURCE_REALTIME_TIMESTAMP=", &realtime, &realtime_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "_SOURCE_MONOTONIC_TIMESTAMP=", &monotonic, &monotonic_len);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_field(data, length, "MESSAGE=", &message, &message_len);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!message)
+                return 0;
+
+        if (priority_len == 1 && *priority >= '0' && *priority <= '7')
+                p = *priority - '0';
+
+        if (mode == OUTPUT_SHORT_MONOTONIC) {
+                uint64_t t;
+                sd_id128_t boot_id;
+
+                r = -ENOENT;
+
+                if (monotonic)
+                        r = safe_atou64(monotonic, &t);
+
+                if (r < 0)
+                        r = sd_journal_get_monotonic_usec(j, &t, &boot_id);
+
+                if (r < 0) {
+                        log_error("Failed to get monotonic: %s", strerror(-r));
+                        return r;
+                }
+
+                fprintf(f, "[%5llu.%06llu]",
+                        (unsigned long long) (t / USEC_PER_SEC),
+                        (unsigned long long) (t % USEC_PER_SEC));
+
+                n += 1 + 5 + 1 + 6 + 1;
+
+        } else {
+                char buf[64];
+                uint64_t x;
+                time_t t;
+                struct tm tm;
+
+                r = -ENOENT;
+
+                if (realtime)
+                        r = safe_atou64(realtime, &x);
+
+                if (r < 0)
+                        r = sd_journal_get_realtime_usec(j, &x);
+
+                if (r < 0) {
+                        log_error("Failed to get realtime: %s", strerror(-r));
+                        return r;
+                }
+
+                t = (time_t) (x / USEC_PER_SEC);
+                if (strftime(buf, sizeof(buf), "%b %d %H:%M:%S", localtime_r(&t, &tm)) <= 0) {
+                        log_error("Failed to format time.");
+                        return r;
+                }
+
+                fputs(buf, f);
+                n += strlen(buf);
+        }
+
+        if (hostname && shall_print(hostname, hostname_len, flags)) {
+                fprintf(f, " %.*s", (int) hostname_len, hostname);
+                n += hostname_len + 1;
+        }
+
+        if (identifier && shall_print(identifier, identifier_len, flags)) {
+                fprintf(f, " %.*s", (int) identifier_len, identifier);
+                n += identifier_len + 1;
+        } else if (comm && shall_print(comm, comm_len, flags)) {
+                fprintf(f, " %.*s", (int) comm_len, comm);
+                n += comm_len + 1;
+        } else
+                fputc(' ', f);
+
+        if (pid && shall_print(pid, pid_len, flags)) {
+                fprintf(f, "[%.*s]", (int) pid_len, pid);
+                n += pid_len + 2;
+        } else if (fake_pid && shall_print(fake_pid, fake_pid_len, flags)) {
+                fprintf(f, "[%.*s]", (int) fake_pid_len, fake_pid);
+                n += fake_pid_len + 2;
+        }
+
+        if (flags & OUTPUT_COLOR) {
+                if (p <= LOG_ERR) {
+                        color_on = ANSI_HIGHLIGHT_RED_ON;
+                        color_off = ANSI_HIGHLIGHT_OFF;
+                } else if (p <= LOG_NOTICE) {
+                        color_on = ANSI_HIGHLIGHT_ON;
+                        color_off = ANSI_HIGHLIGHT_OFF;
+                }
+        }
+
+        if (flags & OUTPUT_SHOW_ALL)
+                fprintf(f, ": %s%.*s%s\n", color_on, (int) message_len, message, color_off);
+        else if (!utf8_is_printable_n(message, message_len)) {
+                char bytes[FORMAT_BYTES_MAX];
+                fprintf(f, ": [%s blob data]\n", format_bytes(bytes, sizeof(bytes), message_len));
+        } else if ((flags & OUTPUT_FULL_WIDTH) || (message_len + n + 1 < n_columns))
+                fprintf(f, ": %s%.*s%s\n", color_on, (int) message_len, message, color_off);
+        else if (n < n_columns && n_columns - n - 2 >= 3) {
+                char *e;
+
+                e = ellipsize_mem(message, message_len, n_columns - n - 2, 90);
+
+                if (!e)
+                        fprintf(f, ": %s%.*s%s\n", color_on, (int) message_len, message, color_off);
+                else
+                        fprintf(f, ": %s%s%s\n", color_on, e, color_off);
+
+                free(e);
+        } else
+                fputs("\n", f);
+
+        return 0;
+}
+
+static int output_verbose(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        const void *data;
+        size_t length;
+        char *cursor;
+        uint64_t realtime;
+        char ts[FORMAT_TIMESTAMP_MAX];
+        int r;
+
+        assert(f);
+        assert(j);
+
+        r = sd_journal_get_realtime_usec(j, &realtime);
+        if (r < 0) {
+                log_error("Failed to get realtime timestamp: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_journal_get_cursor(j, &cursor);
+        if (r < 0) {
+                log_error("Failed to get cursor: %s", strerror(-r));
+                return r;
+        }
+
+        fprintf(f, "%s [%s]\n",
+                format_timestamp(ts, sizeof(ts), realtime),
+                cursor);
+
+        free(cursor);
+
+        SD_JOURNAL_FOREACH_DATA(j, data, length) {
+                if (!shall_print(data, length, flags)) {
+                        const char *c;
+                        char bytes[FORMAT_BYTES_MAX];
+
+                        c = memchr(data, '=', length);
+                        if (!c) {
+                                log_error("Invalid field.");
+                                return -EINVAL;
+                        }
+
+                        fprintf(f, "\t%.*s=[%s blob data]\n",
+                               (int) (c - (const char*) data),
+                               (const char*) data,
+                               format_bytes(bytes, sizeof(bytes), length - (c - (const char *) data) - 1));
+                } else
+                        fprintf(f, "\t%.*s\n", (int) length, (const char*) data);
+        }
+
+        return 0;
+}
+
+static int output_export(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        sd_id128_t boot_id;
+        char sid[33];
+        int r;
+        usec_t realtime, monotonic;
+        char *cursor;
+        const void *data;
+        size_t length;
+
+        assert(j);
+
+        r = sd_journal_get_realtime_usec(j, &realtime);
+        if (r < 0) {
+                log_error("Failed to get realtime timestamp: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_journal_get_monotonic_usec(j, &monotonic, &boot_id);
+        if (r < 0) {
+                log_error("Failed to get monotonic timestamp: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_journal_get_cursor(j, &cursor);
+        if (r < 0) {
+                log_error("Failed to get cursor: %s", strerror(-r));
+                return r;
+        }
+
+        fprintf(f,
+                "__CURSOR=%s\n"
+                "__REALTIME_TIMESTAMP=%llu\n"
+                "__MONOTONIC_TIMESTAMP=%llu\n"
+                "_BOOT_ID=%s\n",
+                cursor,
+                (unsigned long long) realtime,
+                (unsigned long long) monotonic,
+                sd_id128_to_string(boot_id, sid));
+
+        free(cursor);
+
+        SD_JOURNAL_FOREACH_DATA(j, data, length) {
+
+                /* We already printed the boot id, from the data in
+                 * the header, hence let's suppress it here */
+                if (length >= 9 &&
+                    memcmp(data, "_BOOT_ID=", 9) == 0)
+                        continue;
+
+                if (!utf8_is_printable_n(data, length)) {
+                        const char *c;
+                        uint64_t le64;
+
+                        c = memchr(data, '=', length);
+                        if (!c) {
+                                log_error("Invalid field.");
+                                return -EINVAL;
+                        }
+
+                        fwrite(data, c - (const char*) data, 1, f);
+                        fputc('\n', f);
+                        le64 = htole64(length - (c - (const char*) data) - 1);
+                        fwrite(&le64, sizeof(le64), 1, f);
+                        fwrite(c + 1, length - (c - (const char*) data) - 1, 1, f);
+                } else
+                        fwrite(data, length, 1, f);
+
+                fputc('\n', f);
+        }
+
+        fputc('\n', f);
+
+        return 0;
+}
+
+void json_escape(
+                FILE *f,
+                const char* p,
+                size_t l,
+                OutputFlags flags) {
+
+        assert(f);
+        assert(p);
+
+        if (!(flags & OUTPUT_SHOW_ALL) && l > JSON_THRESHOLD)
+
+                fputs("null", f);
+
+        else if (!utf8_is_printable_n(p, l)) {
+                bool not_first = false;
+
+                fputs("[ ", f);
+
+                while (l > 0) {
+                        if (not_first)
+                                fprintf(f, ", %u", (uint8_t) *p);
+                        else {
+                                not_first = true;
+                                fprintf(f, "%u", (uint8_t) *p);
+                        }
+
+                        p++;
+                        l--;
+                }
+
+                fputs(" ]", f);
+        } else {
+                fputc('\"', f);
+
+                while (l > 0) {
+                        if (*p == '"' || *p == '\\') {
+                                fputc('\\', f);
+                                fputc(*p, f);
+                        } else if (*p < ' ')
+                                fprintf(f, "\\u%04x", *p);
+                        else
+                                fputc(*p, f);
+
+                        p++;
+                        l--;
+                }
+
+                fputc('\"', f);
+        }
+}
+
+static int output_json(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        uint64_t realtime, monotonic;
+        char *cursor, *k;
+        const void *data;
+        size_t length;
+        sd_id128_t boot_id;
+        char sid[33];
+        int r;
+        Hashmap *h = NULL;
+        bool done, separator;
+
+        assert(j);
+
+        r = sd_journal_get_realtime_usec(j, &realtime);
+        if (r < 0) {
+                log_error("Failed to get realtime timestamp: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_journal_get_monotonic_usec(j, &monotonic, &boot_id);
+        if (r < 0) {
+                log_error("Failed to get monotonic timestamp: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_journal_get_cursor(j, &cursor);
+        if (r < 0) {
+                log_error("Failed to get cursor: %s", strerror(-r));
+                return r;
+        }
+
+        if (mode == OUTPUT_JSON_PRETTY)
+                fprintf(f,
+                        "{\n"
+                        "\t\"__CURSOR\" : \"%s\",\n"
+                        "\t\"__REALTIME_TIMESTAMP\" : \"%llu\",\n"
+                        "\t\"__MONOTONIC_TIMESTAMP\" : \"%llu\",\n"
+                        "\t\"_BOOT_ID\" : \"%s\"",
+                        cursor,
+                        (unsigned long long) realtime,
+                        (unsigned long long) monotonic,
+                        sd_id128_to_string(boot_id, sid));
+        else {
+                if (mode == OUTPUT_JSON_SSE)
+                        fputs("data: ", f);
+
+                fprintf(f,
+                        "{ \"__CURSOR\" : \"%s\", "
+                        "\"__REALTIME_TIMESTAMP\" : \"%llu\", "
+                        "\"__MONOTONIC_TIMESTAMP\" : \"%llu\", "
+                        "\"_BOOT_ID\" : \"%s\"",
+                        cursor,
+                        (unsigned long long) realtime,
+                        (unsigned long long) monotonic,
+                        sd_id128_to_string(boot_id, sid));
+        }
+        free(cursor);
+
+        h = hashmap_new(string_hash_func, string_compare_func);
+        if (!h)
+                return -ENOMEM;
+
+        /* First round, iterate through the entry and count how often each field appears */
+        SD_JOURNAL_FOREACH_DATA(j, data, length) {
+                const char *eq;
+                char *n;
+                unsigned u;
+
+                if (length >= 9 &&
+                    memcmp(data, "_BOOT_ID=", 9) == 0)
+                        continue;
+
+                eq = memchr(data, '=', length);
+                if (!eq)
+                        continue;
+
+                n = strndup(data, eq - (const char*) data);
+                if (!n) {
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                u = PTR_TO_UINT(hashmap_get(h, n));
+                if (u == 0) {
+                        r = hashmap_put(h, n, UINT_TO_PTR(1));
+                        if (r < 0) {
+                                free(n);
+                                goto finish;
+                        }
+                } else {
+                        r = hashmap_update(h, n, UINT_TO_PTR(u + 1));
+                        free(n);
+                        if (r < 0)
+                                goto finish;
+                }
+        }
+
+        separator = true;
+        do {
+                done = true;
+
+                SD_JOURNAL_FOREACH_DATA(j, data, length) {
+                        const char *eq;
+                        char *kk, *n;
+                        size_t m;
+                        unsigned u;
+
+                        /* We already printed the boot id, from the data in
+                         * the header, hence let's suppress it here */
+                        if (length >= 9 &&
+                            memcmp(data, "_BOOT_ID=", 9) == 0)
+                                continue;
+
+                        eq = memchr(data, '=', length);
+                        if (!eq)
+                                continue;
+
+                        if (separator) {
+                                if (mode == OUTPUT_JSON_PRETTY)
+                                        fputs(",\n\t", f);
+                                else
+                                        fputs(", ", f);
+                        }
+
+                        m = eq - (const char*) data;
+
+                        n = strndup(data, m);
+                        if (!n) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        u = PTR_TO_UINT(hashmap_get2(h, n, (void**) &kk));
+                        if (u == 0) {
+                                /* We already printed this, let's jump to the next */
+                                free(n);
+                                separator = false;
+
+                                continue;
+                        } else if (u == 1) {
+                                /* Field only appears once, output it directly */
+
+                                json_escape(f, data, m, flags);
+                                fputs(" : ", f);
+
+                                json_escape(f, eq + 1, length - m - 1, flags);
+
+                                hashmap_remove(h, n);
+                                free(kk);
+                                free(n);
+
+                                separator = true;
+
+                                continue;
+
+                        } else {
+                                /* Field appears multiple times, output it as array */
+                                json_escape(f, data, m, flags);
+                                fputs(" : [ ", f);
+                                json_escape(f, eq + 1, length - m - 1, flags);
+
+                                /* Iterate through the end of the list */
+
+                                while (sd_journal_enumerate_data(j, &data, &length) > 0) {
+                                        if (length < m + 1)
+                                                continue;
+
+                                        if (memcmp(data, n, m) != 0)
+                                                continue;
+
+                                        if (((const char*) data)[m] != '=')
+                                                continue;
+
+                                        fputs(", ", f);
+                                        json_escape(f, (const char*) data + m + 1, length - m - 1, flags);
+                                }
+
+                                fputs(" ]", f);
+
+                                hashmap_remove(h, n);
+                                free(kk);
+                                free(n);
+
+                                /* Iterate data fields form the beginning */
+                                done = false;
+                                separator = true;
+
+                                break;
+                        }
+                }
+
+        } while (!done);
+
+        if (mode == OUTPUT_JSON_PRETTY)
+                fputs("\n}\n", f);
+        else if (mode == OUTPUT_JSON_SSE)
+                fputs("}\n\n", f);
+        else
+                fputs(" }\n", f);
+
+        r = 0;
+
+finish:
+        while ((k = hashmap_steal_first_key(h)))
+                free(k);
+
+        hashmap_free(h);
+
+        return r;
+}
+
+static int output_cat(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        const void *data;
+        size_t l;
+        int r;
+
+        assert(j);
+        assert(f);
+
+        r = sd_journal_get_data(j, "MESSAGE", &data, &l);
+        if (r < 0) {
+                /* An entry without MESSAGE=? */
+                if (r == -ENOENT)
+                        return 0;
+
+                log_error("Failed to get data: %s", strerror(-r));
+                return r;
+        }
+
+        assert(l >= 8);
+
+        fwrite((const char*) data + 8, 1, l - 8, f);
+        fputc('\n', f);
+
+        return 0;
+}
+
+static int (*output_funcs[_OUTPUT_MODE_MAX])(
+                FILE *f,
+                sd_journal*j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) = {
+
+        [OUTPUT_SHORT] = output_short,
+        [OUTPUT_SHORT_MONOTONIC] = output_short,
+        [OUTPUT_VERBOSE] = output_verbose,
+        [OUTPUT_EXPORT] = output_export,
+        [OUTPUT_JSON] = output_json,
+        [OUTPUT_JSON_PRETTY] = output_json,
+        [OUTPUT_JSON_SSE] = output_json,
+        [OUTPUT_CAT] = output_cat
+};
+
+int output_journal(
+                FILE *f,
+                sd_journal *j,
+                OutputMode mode,
+                unsigned n_columns,
+                OutputFlags flags) {
+
+        int ret;
+        assert(mode >= 0);
+        assert(mode < _OUTPUT_MODE_MAX);
+
+        if (n_columns <= 0)
+                n_columns = columns();
+
+        ret = output_funcs[mode](f, j, mode, n_columns, flags);
+        fflush(stdout);
+        return ret;
+}
+
+int show_journal_by_unit(
+                FILE *f,
+                const char *unit,
+                OutputMode mode,
+                unsigned n_columns,
+                usec_t not_before,
+                unsigned how_many,
+                OutputFlags flags) {
+
+        _cleanup_free_ char *m1 = NULL, *m2 = NULL, *m3 = NULL;
+        sd_journal *j = NULL;
+        int r;
+        unsigned line = 0;
+        bool need_seek = false;
+        int warn_cutoff = flags & OUTPUT_WARN_CUTOFF;
+
+        assert(mode >= 0);
+        assert(mode < _OUTPUT_MODE_MAX);
+        assert(unit);
+
+        if (!endswith(unit, ".service") &&
+            !endswith(unit, ".socket") &&
+            !endswith(unit, ".mount") &&
+            !endswith(unit, ".swap"))
+                return 0;
+
+        if (how_many <= 0)
+                return 0;
+
+        if (asprintf(&m1, "_SYSTEMD_UNIT=%s", unit) < 0 ||
+            asprintf(&m2, "COREDUMP_UNIT=%s", unit) < 0 ||
+            asprintf(&m3, "UNIT=%s", unit) < 0) {
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY|SD_JOURNAL_SYSTEM_ONLY);
+        if (r < 0)
+                goto finish;
+
+        /* Look for messages from the service itself */
+        r = sd_journal_add_match(j, m1, 0);
+        if (r < 0)
+                goto finish;
+
+        /* Look for coredumps of the service */
+        r = sd_journal_add_disjunction(j);
+        if (r < 0)
+                goto finish;
+        r = sd_journal_add_match(j, "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1", 0);
+        if (r < 0)
+                goto finish;
+        r = sd_journal_add_match(j, m2, 0);
+        if (r < 0)
+                goto finish;
+
+        /* Look for messages from PID 1 about this service */
+        r = sd_journal_add_disjunction(j);
+        if (r < 0)
+                goto finish;
+        r = sd_journal_add_match(j, "_PID=1", 0);
+        if (r < 0)
+                goto finish;
+        r = sd_journal_add_match(j, m3, 0);
+        if (r < 0)
+                goto finish;
+
+        /* Seek to end */
+        r = sd_journal_seek_tail(j);
+        if (r < 0)
+                goto finish;
+
+        r = sd_journal_previous_skip(j, how_many);
+        if (r < 0)
+                goto finish;
+
+        for (;;) {
+                for (;;) {
+                        usec_t usec;
+
+                        if (need_seek) {
+                                r = sd_journal_next(j);
+                                if (r < 0)
+                                        goto finish;
+                        }
+
+                        if (r == 0)
+                                break;
+
+                        need_seek = true;
+
+                        if (not_before > 0) {
+                                r = sd_journal_get_monotonic_usec(j, &usec, NULL);
+
+                                /* -ESTALE is returned if the
+                                   timestamp is not from this boot */
+                                if (r == -ESTALE)
+                                        continue;
+                                else if (r < 0)
+                                        goto finish;
+
+                                if (usec < not_before)
+                                        continue;
+                        }
+
+                        line ++;
+
+                        r = output_journal(f, j, mode, n_columns, flags);
+                        if (r < 0)
+                                goto finish;
+                }
+
+                if (warn_cutoff && line < how_many && not_before > 0) {
+                        sd_id128_t boot_id;
+                        usec_t cutoff;
+
+                        /* Check whether the cutoff line is too early */
+
+                        r = sd_id128_get_boot(&boot_id);
+                        if (r < 0)
+                                goto finish;
+
+                        r = sd_journal_get_cutoff_monotonic_usec(j, boot_id, &cutoff, NULL);
+                        if (r < 0)
+                                goto finish;
+
+                        if (r > 0 && not_before < cutoff)
+                                fprintf(f, "Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.\n");
+
+                        warn_cutoff = false;
+                }
+
+                if (!(flags & OUTPUT_FOLLOW))
+                        break;
+
+                r = sd_journal_wait(j, (usec_t) -1);
+                if (r < 0)
+                        goto finish;
+
+        }
+
+finish:
+        if (j)
+                sd_journal_close(j);
+
+        return r;
+}
+
+static const char *const output_mode_table[_OUTPUT_MODE_MAX] = {
+        [OUTPUT_SHORT] = "short",
+        [OUTPUT_SHORT_MONOTONIC] = "short-monotonic",
+        [OUTPUT_VERBOSE] = "verbose",
+        [OUTPUT_EXPORT] = "export",
+        [OUTPUT_JSON] = "json",
+        [OUTPUT_JSON_PRETTY] = "json-pretty",
+        [OUTPUT_JSON_SSE] = "json-sse",
+        [OUTPUT_CAT] = "cat"
+};
+
+DEFINE_STRING_TABLE_LOOKUP(output_mode, OutputMode);