[systemd-devel] [PATCH] journal: return -ECHILD after a fork
Zbigniew Jędrzejewski-Szmek
zbyszek at in.waw.pl
Wed Jun 26 16:55:48 PDT 2013
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?
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;
--
1.8.2.562.g931e949
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