From 4171a6676c74846c9c189f3a92b97bbcd4a11a13 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 13 Jul 2012 19:00:48 +0200 Subject: [PATCH 1/1] man: document sd_journal_get_data() and friends --- Makefile.am | 15 ++- man/sd_journal_get_data.xml | 199 ++++++++++++++++++++++++++++++++++++ man/sd_journal_next.xml | 18 ++++ src/systemd/sd-journal.h | 1 + 4 files changed, 231 insertions(+), 2 deletions(-) create mode 100644 man/sd_journal_get_data.xml diff --git a/Makefile.am b/Makefile.am index 119d96888..b54c21b37 100644 --- a/Makefile.am +++ b/Makefile.am @@ -502,7 +502,8 @@ MANPAGES = \ man/sd_journal_print.3 \ man/sd_journal_stream_fd.3 \ man/sd_journal_open.3 \ - man/sd_journal_next.3 + man/sd_journal_next.3 \ + man/sd_journal_get_data.3 MANPAGES_ALIAS = \ man/reboot.8 \ @@ -547,7 +548,12 @@ MANPAGES_ALIAS = \ man/sd_journal_close.3 \ man/sd_journal_previous.3 \ man/sd_journal_next_skip.3 \ - man/sd_journal_previous_skip.3 + man/sd_journal_previous_skip.3 \ + man/SD_JOURNAL_FOREACH.3 \ + man/SD_JOURNAL_FOREACH_BACKWARDS.3 \ + man/sd_journal_enumerate_data.3 \ + man/sd_journal_restart_data.3 \ + man/SD_JOURNAL_FOREACH_DATA.3 man/reboot.8: man/halt.8 man/poweroff.8: man/halt.8 @@ -592,6 +598,11 @@ man/sd_journal_close.3: man/sd_journal_open.3 man/sd_journal_previous.3: man/sd_journal_next.3 man/sd_journal_next_skip.3: man/sd_journal_next.3 man/sd_journal_previous_skip.3: man/sd_journal_next.3 +man/SD_JOURNAL_FOREACH.3: man/sd_journal_next.3 +man/SD_JOURNAL_FOREACH_BACKWARDS.3: man/sd_journal_next.3 +man/sd_journal_enumerate_data.3: man/sd_journal_get_data.3 +man/sd_journal_restart_data.3: man/sd_journal_get_data.3 +man/SD_JOURNAL_FOREACH_DATA.3: man/sd_journal_get_data.3 XML_FILES = \ ${patsubst %.1,%.xml,${patsubst %.3,%.xml,${patsubst %.5,%.xml,${patsubst %.7,%.xml,${patsubst %.8,%.xml,$(MANPAGES)}}}}} diff --git a/man/sd_journal_get_data.xml b/man/sd_journal_get_data.xml new file mode 100644 index 000000000..9d8a4a222 --- /dev/null +++ b/man/sd_journal_get_data.xml @@ -0,0 +1,199 @@ + + + + + + + + + sd_journal_get_data + systemd + + + + Developer + Lennart + Poettering + lennart@poettering.net + + + + + + sd_journal_get_data + 3 + + + + sd_journal_get_data + sd_journal_enumerate_data + sd_journal_restart_data + SD_JOURNAL_FOREACH_DATA + Read data fields from the current journal entry + + + + + #include <systemd/sd-journal.h> + + + int sd_journal_get_data + sd_journal* j + const char* field + const void** data + size_t* length + + + + int sd_journal_enumerate_data + sd_journal* j + const void** data + size_t* length + + + + int sd_journal_restart_data + sd_journal* j + + + + SD_JOURNAL_FOREACH_DATA + sd_journal* j + const void* data + size_t length + + + + + + + Description + + sd_journal_get_data() gets + the data object associated with a specific field from + the current journal entry. It takes four arguments: + the journal context object, a string with the field + name to request, plus a pair of pointers to + pointer/size variables where the data object and its + size shall be stored in. The field name should be an + entry field name. Well-known field names are listed in + systemd.journal-fields7. The + returned data is in a read-only memory map and is only + valid until the next invocation of + sd_journal_get_data() or + sd_journal_enumerate_data(), or + the read pointer is altered. Note that the data + returned will be prefixed with the field name and + '='. + + sd_journal_enumerate_data() + may be used to iterate through all fields of the + current entry. On each invocation the data for the + next field is returned. The order of these fields is + not defined. The data returned is in the same format + as with sd_journal_get_data() and + also follows the same life-time semantics. + + sd_journal_restart_data() + resets the data enumeration index to the beginning of + the entry. The next invocation of + sd_journal_enumerate_data() will return the first + field of the entry again. + + Note that the + SD_JOURNAL_FOREACH_DATA() macro + may be used as a wrapper around + sd_journal_restart_data() and + sd_journal_enumerate_data(). + + Note that these functions will not work before + sd_journal_next3 + (or related call) has not been called at least + once. + + + + Return Value + + sd_journal_get_data() + returns 0 on success or a negative errno-style error + code. If the current entry does not include the + specified field -ENOENT is returned. If + sd_journal_next3 + has not been called at least once -EADDRNOTAVAIL is + returned. sd_journal_enumerate_data() + returns a positive integer if the next field has been + read, 0 when no more fields are known, or a negative + errno-style error + code. sd_journal_restart_data() + returns nothing. + + + + Notes + + The sd_journal_get_data(), + sd_journal_enumerate_data() and + sd_journal_restart_data() + interfaces are available as shared library, which can + be compiled and linked to with the + libsystemd-journal + pkg-config1 + file. + + + + Examples + + See + sd_journal_next3 + for a complete example how to use + sd_journal_get_data(). + + Use the + SD_JOURNAL_FOREACH_DATA macro to + iterate through all fields of the current journal + entry: + + ... +int print_fields(sd_journal *j) { + const void *data; + size_t l; + SD_JOURNAL_FOREACH_DATA(j, data, length) + printf("%.*s\n", (int) length, data); +} +... + + + + + See Also + + + systemd1, + systemd.journal-fields7, + sd-journal3, + sd_journal_open3, + sd_journal_next3 + + + + diff --git a/man/sd_journal_next.xml b/man/sd_journal_next.xml index f55ee1574..90fcecb10 100644 --- a/man/sd_journal_next.xml +++ b/man/sd_journal_next.xml @@ -47,6 +47,8 @@ sd_journal_previous sd_journal_next_skip sd_journal_previous_skip + SD_JOURNAL_FOREACH + SD_JOURNAL_FOREACH_BACKWARDS Advance or set back the read pointer in the journal @@ -76,6 +78,15 @@ uint64_t skip + + SD_JOURNAL_FOREACH + sd_journal* j + + + + SD_JOURNAL_FOREACH_BACKWARDS + sd_journal* j + @@ -105,6 +116,13 @@ that the entry then pointing to is later in time than then previous one, or has the same timestamp. + Note that + sd_journal_get_data3 + and related calls will fail unless + sd_journal_next() has been + invoked at least once in order to position the read + pointer on a journal entry. + Note that the SD_JOURNAL_FOREACH() macro may be used as a wrapper around diff --git a/src/systemd/sd-journal.h b/src/systemd/sd-journal.h index 935b0452b..e70f575ce 100644 --- a/src/systemd/sd-journal.h +++ b/src/systemd/sd-journal.h @@ -85,6 +85,7 @@ int sd_journal_next_skip(sd_journal *j, uint64_t skip); int sd_journal_get_realtime_usec(sd_journal *j, uint64_t *ret); int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *ret, sd_id128_t *ret_boot_id); + int sd_journal_get_data(sd_journal *j, const char *field, const void **data, size_t *l); int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t *l); void sd_journal_restart_data(sd_journal *j); -- 2.30.2