[systemd-devel] [PATCH] journal: return -ECHILD after a fork
Lennart Poettering
lennart at poettering.net
Tue Jul 16 08:50:27 PDT 2013
On Wed, 26.06.13 19:55, Zbigniew Jędrzejewski-Szmek (zbyszek at in.waw.pl) wrote:
> A few asserts are replaced with 'return -EINVAL'. I think that
> assert should not be used to check argument in public functions.
>
> Fields in struct sd_journal are rearranged to make it less
> swiss-cheesy.
> ---
> Does this look sound?
Yupp! Looks great! Please commit!
>
> Zbyszek
>
> TODO | 5 +--
> man/sd_journal_open.xml | 7 ++++
> src/journal/journal-internal.h | 18 +++++-----
> src/journal/sd-journal.c | 80 +++++++++++++++++++++++++++++++++++++++---
> 4 files changed, 93 insertions(+), 17 deletions(-)
>
> diff --git a/TODO b/TODO
> index caba4e3..2968d18 100644
> --- a/TODO
> +++ b/TODO
> @@ -68,7 +68,7 @@ Features:
>
> * document systemd-journal-flush.service properly
>
> -* chane systemd-journal-flush into a service that stays around during
> +* change systemd-journal-flush into a service that stays around during
> boot, and causes the journal to be moved back to /run on shutdown,
> so that we don't keep /var busy. This needs to happen synchronously,
> hence doing this via signals is not going to work.
> @@ -76,9 +76,6 @@ Features:
> * allow implementation of InaccessibleDirectories=/ plus
> ReadOnlyDirectories=... for whitelisting files for a service.
>
> -* libsystemd-journal:
> - - return ECHILD as soon as somebody tries to reuse a journal object across a fork()
> -
> * libsystemd-bus:
> - default policy (allow uid == 0 and our own uid)
> - enforce alignment of pointers passed in
> diff --git a/man/sd_journal_open.xml b/man/sd_journal_open.xml
> index d7ea8ff..b2f6f9e 100644
> --- a/man/sd_journal_open.xml
> +++ b/man/sd_journal_open.xml
> @@ -131,6 +131,13 @@
> can be rotated at any moment, and the opening of
> specific files is inherently racy.</para>
>
> + <para><varname>sd_journal</varname> objects cannot be
> + used in the child after a fork. Functions which take a
> + journal object as an argument
> + (<function>sd_journal_next()</function> and others)
> + will return <constant>-ECHILD</constant> after a fork.
> + </para>
> +
> <para><function>sd_journal_close()</function> will
> close the journal context allocated with
> <function>sd_journal_open()</function> or
> diff --git a/src/journal/journal-internal.h b/src/journal/journal-internal.h
> index 5b717f8..5bc6535 100644
> --- a/src/journal/journal-internal.h
> +++ b/src/journal/journal-internal.h
> @@ -97,8 +97,6 @@ struct Directory {
> };
>
> struct sd_journal {
> - int flags;
> -
> char *path;
>
> Hashmap *files;
> @@ -109,27 +107,29 @@ struct sd_journal {
> JournalFile *current_file;
> uint64_t current_field;
>
> - Hashmap *directories_by_path;
> - Hashmap *directories_by_wd;
> -
> - int inotify_fd;
> -
> Match *level0, *level1, *level2;
>
> + pid_t original_pid;
> +
> + int inotify_fd;
> unsigned current_invalidate_counter, last_invalidate_counter;
> + usec_t last_process_usec;
>
> char *unique_field;
> JournalFile *unique_file;
> uint64_t unique_offset;
>
> + int flags;
> +
> bool on_network;
> bool no_new_files;
>
> size_t data_threshold;
>
> - Set *errors;
> + Hashmap *directories_by_path;
> + Hashmap *directories_by_wd;
>
> - usec_t last_process_usec;
> + Set *errors;
> };
>
> char *journal_make_match_string(sd_journal *j);
> diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
> index 1e70739..81b0c13 100644
> --- a/src/journal/sd-journal.c
> +++ b/src/journal/sd-journal.c
> @@ -50,6 +50,15 @@
>
> #define DEFAULT_DATA_THRESHOLD (64*1024)
>
> +static bool journal_pid_changed(sd_journal *j) {
> + assert(j);
> +
> + /* We don't support people creating a journal object and
> + * keeping it around over a fork(). Let's complain. */
> +
> + return j->original_pid != getpid();
> +}
> +
> /* We return an error here only if we didn't manage to
> memorize the real error. */
> static int set_put_error(sd_journal *j, int r) {
> @@ -209,6 +218,8 @@ _public_ int sd_journal_add_match(sd_journal *j, const void *data, size_t size)
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (!data)
> return -EINVAL;
> @@ -303,7 +314,10 @@ fail:
> }
>
> _public_ int sd_journal_add_conjunction(sd_journal *j) {
> - assert(j);
> + if (!j)
> + return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (!j->level0)
> return 0;
> @@ -321,7 +335,10 @@ _public_ int sd_journal_add_conjunction(sd_journal *j) {
> }
>
> _public_ int sd_journal_add_disjunction(sd_journal *j) {
> - assert(j);
> + if (!j)
> + return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (!j->level0)
> return 0;
> @@ -391,7 +408,6 @@ char *journal_make_match_string(sd_journal *j) {
> }
>
> _public_ void sd_journal_flush_matches(sd_journal *j) {
> -
> if (!j)
> return;
>
> @@ -870,6 +886,8 @@ static int real_journal_next(sd_journal *j, direction_t direction) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> HASHMAP_FOREACH(f, j->files, i) {
> bool found;
> @@ -922,6 +940,8 @@ static int real_journal_next_skip(sd_journal *j, direction_t direction, uint64_t
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (skip == 0) {
> /* If this is not a discrete skip, then at least
> @@ -962,6 +982,8 @@ _public_ int sd_journal_get_cursor(sd_journal *j, char **cursor) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!cursor)
> return -EINVAL;
>
> @@ -1001,6 +1023,8 @@ _public_ int sd_journal_seek_cursor(sd_journal *j, const char *cursor) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (isempty(cursor))
> return -EINVAL;
>
> @@ -1100,6 +1124,8 @@ _public_ int sd_journal_test_cursor(sd_journal *j, const char *cursor) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (isempty(cursor))
> return -EINVAL;
>
> @@ -1178,6 +1204,8 @@ _public_ int sd_journal_test_cursor(sd_journal *j, const char *cursor) {
> _public_ int sd_journal_seek_monotonic_usec(sd_journal *j, sd_id128_t boot_id, uint64_t usec) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> reset_location(j);
> j->current_location.type = LOCATION_SEEK;
> @@ -1191,6 +1219,8 @@ _public_ int sd_journal_seek_monotonic_usec(sd_journal *j, sd_id128_t boot_id, u
> _public_ int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> reset_location(j);
> j->current_location.type = LOCATION_SEEK;
> @@ -1203,6 +1233,8 @@ _public_ int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec) {
> _public_ int sd_journal_seek_head(sd_journal *j) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> reset_location(j);
> j->current_location.type = LOCATION_HEAD;
> @@ -1213,6 +1245,8 @@ _public_ int sd_journal_seek_head(sd_journal *j) {
> _public_ int sd_journal_seek_tail(sd_journal *j) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> reset_location(j);
> j->current_location.type = LOCATION_TAIL;
> @@ -1651,6 +1685,7 @@ static sd_journal *journal_new(int flags, const char *path) {
> if (!j)
> return NULL;
>
> + j->original_pid = getpid();
> j->inotify_fd = -1;
> j->flags = flags;
> j->data_threshold = DEFAULT_DATA_THRESHOLD;
> @@ -1812,6 +1847,8 @@ _public_ int sd_journal_get_realtime_usec(sd_journal *j, uint64_t *ret) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!ret)
> return -EINVAL;
>
> @@ -1838,6 +1875,8 @@ _public_ int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *ret, sd_id12
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> f = j->current_file;
> if (!f)
> @@ -1904,6 +1943,8 @@ _public_ int sd_journal_get_data(sd_journal *j, const char *field, const void **
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!field)
> return -EINVAL;
> if (!data)
> @@ -2030,6 +2071,8 @@ _public_ int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!data)
> return -EINVAL;
> if (!size)
> @@ -2080,6 +2123,8 @@ _public_ int sd_journal_get_fd(sd_journal *j) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (j->inotify_fd >= 0)
> return j->inotify_fd;
> @@ -2107,6 +2152,8 @@ _public_ int sd_journal_get_events(sd_journal *j) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> fd = sd_journal_get_fd(j);
> if (fd < 0)
> @@ -2120,6 +2167,8 @@ _public_ int sd_journal_get_timeout(sd_journal *j, uint64_t *timeout_usec) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!timeout_usec)
> return -EINVAL;
>
> @@ -2220,6 +2269,8 @@ _public_ int sd_journal_process(sd_journal *j) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> j->last_process_usec = now(CLOCK_MONOTONIC);
>
> @@ -2258,7 +2309,10 @@ _public_ int sd_journal_wait(sd_journal *j, uint64_t timeout_usec) {
> int r;
> uint64_t t;
>
> - assert(j);
> + if (!j)
> + return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> if (j->inotify_fd < 0) {
>
> @@ -2307,6 +2361,8 @@ _public_ int sd_journal_get_cutoff_realtime_usec(sd_journal *j, uint64_t *from,
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!from && !to)
> return -EINVAL;
> if (from == to)
> @@ -2348,6 +2404,8 @@ _public_ int sd_journal_get_cutoff_monotonic_usec(sd_journal *j, sd_id128_t boot
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!from && !to)
> return -EINVAL;
> if (from == to)
> @@ -2405,6 +2463,8 @@ _public_ int sd_journal_get_usage(sd_journal *j, uint64_t *bytes) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!bytes)
> return -EINVAL;
>
> @@ -2426,6 +2486,8 @@ _public_ int sd_journal_query_unique(sd_journal *j, const char *field) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (isempty(field))
> return -EINVAL;
> if (!field_is_valid(field))
> @@ -2450,6 +2512,8 @@ _public_ int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!data)
> return -EINVAL;
> if (!l)
> @@ -2562,6 +2626,8 @@ _public_ void sd_journal_restart_unique(sd_journal *j) {
> _public_ int sd_journal_reliable_fd(sd_journal *j) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> return !j->on_network;
> }
> @@ -2595,6 +2661,8 @@ _public_ int sd_journal_get_catalog(sd_journal *j, char **ret) {
>
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!ret)
> return -EINVAL;
>
> @@ -2632,6 +2700,8 @@ _public_ int sd_journal_get_catalog_for_message_id(sd_id128_t id, char **ret) {
> _public_ int sd_journal_set_data_threshold(sd_journal *j, size_t sz) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
>
> j->data_threshold = sz;
> return 0;
> @@ -2640,6 +2710,8 @@ _public_ int sd_journal_set_data_threshold(sd_journal *j, size_t sz) {
> _public_ int sd_journal_get_data_threshold(sd_journal *j, size_t *sz) {
> if (!j)
> return -EINVAL;
> + if (journal_pid_changed(j))
> + return -ECHILD;
> if (!sz)
> return -EINVAL;
>
Lennart
--
Lennart Poettering - Red Hat, Inc.
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