----- Original Message -----
> From: "Jan Chaloupka" <jchal...@redhat.com>
> To: libcg-devel@lists.sourceforge.net
> Cc: jchal...@redhat.com, varek...@redhat.com
> Sent: Thursday, July 24, 2014 8:20:51 AM
> Subject: [PATCH 1/2] api.c: Adding support for loading configuration files
> from cgrules.d directory
>
> Implementation of loading rules from /etc/cgrules.d/. Explanation is in the
> cover letter. New function cgroup_parse_rules_file created,
> calling cgroup_parse_rules. cgroup_parse_rules is invoked only in
> cgroup_change_cgroup_flags, cgroup_init_rules_cache and
> cgroup_reload_cached_rules functions. For them the change in
> cgroup_parse_rules
> implementation is transpart.
>
> Tested with two configuration files in /etc/cgrules.d/ and all rules
> in /etc/cgrules.conf commented out:
>
> $ cat /etc/cgrules.conf
> #*:ls cpu strom/%u
> #*:sleep memory les/%g
>
> $ cat /etc/cgrules.d/cgrules1.conf
> *:ls cpu strom/%u
>
> $ cat /etc/cgrules.d/cgrules2.conf
> *:sleep memory les/%g
>
> plus cgconfig.[c|d/*] files:
> $ cat /etc/cgconfig.conf
> mount {
> cpuset = /cgroup/cpuset;
> cpu = /cgroup/cpu;
> cpuacct = /cgroup/cpuacct;
> memory = /cgroup/memory;
> devices = /cgroup/devices;
> freezer = /cgroup/freezer;
> net_cls = /cgroup/net_cls;
> blkio = /cgroup/blkio;
> }
>
> $ cat /etc/cgconfig.d/small.conf
> template strom/%u {
> cpu {}
> }
>
> group vetev {
> cpu {}
> }
>
> $ cat /etc/cgconfig.d/medium.conf
> template les/%g {
> memory {}
> }
>
> group drevo/listi {
> memory {}
> }
>
> Tested to cache reload as well by sending SIGUSR2 signal to running
> cgrulesengd process. After first reload I commented out all rules => no
> rules match after invoking ls command. After second reload I uncommented
> out ls rule => rule match after invoking ls command. After third reload
> I uncommented out ls and sleep rule => debug output of cgrulesengd shows
> both rules loaded in the cache
>
> Changelog:
> * CGROUP_PARSE_STATE_UNLOCK removed
> * reformulation of comment to "Cannot read directory. However,
> CGRULES_CONF_FILE is succesfully parsed. Thus return as a success for
> back compatibility."
> * errno = 0 removed, once it is not zero, function returns, so need to set
> it to 0 in every iteration
> * fprintf replaced by cgroup_err
> * added missing unlocks + new label unlock_list for all returns
>
> This
> - * finds a rule matching the given UID or GID. It will store this rule in
> rl,
> + * finds a rule matching the given UID or GID. It will store this rule in
> trl,
> is valid correction. "It will store this rule in rl" talks about cache being
> disabled. In this case, it is stored into trl.
>
> Signed-off-by: Jan Chaloupka <jchal...@redhat.com>
Acked-by: Ivana Hutarova Varekova <varek...@redhat.com>
> ---
> src/api.c | 159
> +++++++++++++++++++++++++++++++++++++++++++---
> src/libcgroup-internal.h | 1
> 2 files changed, 148 insertions(+), 12 deletions(-)
>
> diff --git a/src/api.c b/src/api.c
> index 0b3d8a0..5751b8f 100644
> --- a/src/api.c
> +++ b/src/api.c
> @@ -473,17 +473,19 @@ static char *cg_skip_unused_charactors_in_rule(char
> *rule)
> * The cache parameter alters the behavior of this function. If true, this
> * function will read the entire configuration file and store the results in
> * rl (global rules list). If false, this function will only parse until it
> - * finds a rule matching the given UID or GID. It will store this rule in
> rl,
> + * finds a rule matching the given UID or GID. It will store this rule in
> trl,
> * as well as any children rules (rules that begin with a %) that it has.
> *
> * This function is NOT thread safe!
> + * @param filename configuration file to parse
> * @param cache True to cache rules, else false
> * @param muid If cache is false, the UID to match against
> * @param mgid If cache is false, the GID to match against
> * @return 0 on success, -1 if no cache and match found, > 0 on error.
> * TODO: Make this function thread safe!
> + *
> */
> -static int cgroup_parse_rules(bool cache, uid_t muid,
> +static int cgroup_parse_rules_file(char *filename, bool cache, uid_t muid,
> gid_t mgid, const char *mprocname)
> {
> /* File descriptor for the configuration file */
> @@ -544,21 +546,19 @@ static int cgroup_parse_rules(bool cache, uid_t muid,
> else
> lst = &trl;
>
> - /* If our list already exists, clean it. */
> - if (lst->head)
> - cgroup_free_rule_list(lst);
> -
> /* Open the configuration file. */
> - pthread_rwlock_wrlock(&rl_lock);
> - fp = fopen(CGRULES_CONF_FILE, "re");
> + fp = fopen(filename, "re");
> if (!fp) {
> cgroup_warn("Warning: failed to open configuration file %s:
> %s\n",
> - CGRULES_CONF_FILE, strerror(errno));
> - goto unlock;
> + filename, strerror(errno));
> +
> + ret = ECGRULESPARSEFAIL; /* originally ret = 0, but */
> + /* this is parse fail, not success */
> + goto finish;
> }
>
> /* Now, parse the configuration file one line at a time. */
> - cgroup_dbg("Parsing configuration file.\n");
> + cgroup_dbg("Parsing configuration file %s.\n", filename);
> while (fgets(buff, sizeof(buff), fp) != NULL) {
> linenum++;
>
> @@ -804,8 +804,143 @@ parsefail:
>
> close:
> fclose(fp);
> -unlock:
> +finish:
> + return ret;
> +}
> +
> +/**
> + * Parse CGRULES_CONF_FILE and all files in CGRULES_CONF_FILE_DIR.
> + * If CGRULES_CONF_FILE_DIR does not exists or can not be read,
> + * parse only CGRULES_CONF_FILE. This way we keep the back compatibility.
> + *
> + * Original description of this function moved to cgroup_parse_rules_file.
> + * Also cloned and all occurences of file changed to files.
> + *
> + * Parse the configuration files that maps UID/GIDs to cgroups. If ever the
> + * configuration files are modified, applications should call this function
> to
> + * load the new configuration rules. The function caller is responsible for
> + * calling free() on each rule in the list.
> + *
> + * The cache parameter alters the behavior of this function. If true, this
> + * function will read the entire content of all configuration files and
> store
> + * the results in rl (global rules list). If false, this function will only
> + * parse until it finds a file and a rule matching the given UID or GID.
> + * The remaining files are skipped. It will store this rule in trl,
> + * as well as any children rules (rules that begin with a %) that it has.
> + *
> + * Files can be read in an random order so the first match must not be
> + * dependent on it. Thus construct the rules the way not to break
> + * this assumption.
> + *
> + * This function is NOT thread safe!
> + * @param cache True to cache rules, else false
> + * @param muid If cache is false, the UID to match against
> + * @param mgid If cache is false, the GID to match against
> + * @return 0 on success, -1 if no cache and match found, > 0 on error.
> + * TODO: Make this function thread safe!
> + */
> +static int cgroup_parse_rules(bool cache, uid_t muid,
> + gid_t mgid, const char *mprocname)
> +{
> + int ret;
> +
> + /* Pointer to the list that we're using */
> + struct cgroup_rule_list *lst = NULL;
> +
> + /* Directory variables */
> + DIR *d;
> + struct dirent *item;
> + const char *dirname = CGRULES_CONF_DIR;
> + char *tmp;
> + int sret;
> +
> + /* Determine which list we're using. */
> + if (cache)
> + lst = &rl;
> + else
> + lst = &trl;
> +
> + /* If our list already exists, clean it. */
> + if (lst->head)
> + cgroup_free_rule_list(lst);
> +
> + pthread_rwlock_wrlock(&rl_lock);
> +
> + /* Parse CGRULES_CONF_FILE configuration file (back compatibility). */
> + ret = cgroup_parse_rules_file(CGRULES_CONF_FILE,
> + cache, muid, mgid, mprocname);
> +
> + /*
> + * if match (ret = -1), stop parsing other files, just return
> + * or ret > 0 => error
> + */
> + if (ret != 0) {
> + pthread_rwlock_unlock(&rl_lock);
> + return ret;
> + }
> +
> + /* Continue parsing */
> + d = opendir(dirname);
> + if (!d) {
> + cgroup_warn("Warning: Failed to open directory %s: %s\n",
> + dirname, strerror(errno));
> +
> + /*
> + * Cannot read directory. However, CGRULES_CONF_FILE is
> + * succesfully parsed. Thus return as a success
> + * for back compatibility.
> + */
> + pthread_rwlock_unlock(&rl_lock);
> +
> + return 0;
> + }
> +
> + /* read all files from CGRULES_CONF_FILE_DIR */
> + do {
> + item = readdir(d);
> + if (item && (item->d_type == DT_REG
> + || item->d_type == DT_LNK)) {
> +
> + sret = asprintf(&tmp, "%s/%s", dirname, item->d_name);
> + if (sret < 0) {
> + cgroup_err("Out of memory\n");
> +
> + /*
> + * Cannot read directory. However,
> CGRULES_CONF_FILE is
> + * succesfully parsed. Thus return as a success
> + * for back compatibility.
> + */
> + ret = 0;
> + goto unlock_list;
> + }
> +
> + cgroup_dbg("Parsing cgrules file: %s\n", tmp);
> + ret = cgroup_parse_rules_file(tmp,
> + cache, muid, mgid, mprocname);
> +
> + free(tmp);
> +
> + /* match with cache disabled? */
> + if (ret != 0)
> + goto unlock_list;
> + }
> + if (!item && errno) {
> + cgroup_warn("Warning: cannot read %s: %s\n",
> + dirname, strerror(errno));
> + /*
> + * Cannot read an item. But continue for
> + * back compatibility as a success.
> + */
> + ret = 0;
> + goto unlock_list;
> + }
> + } while (item != NULL);
> +
> +unlock_list:
> + closedir(d);
> +
> pthread_rwlock_unlock(&rl_lock);
> +
> return ret;
> }
>
> diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
> index c128788..9875dd9 100644
> --- a/src/libcgroup-internal.h
> +++ b/src/libcgroup-internal.h
> @@ -53,6 +53,7 @@ __BEGIN_DECLS
> #define CGCONFIG_CONF_DIR "/etc/cgconfig.d"
>
> #define CGRULES_CONF_FILE "/etc/cgrules.conf"
> +#define CGRULES_CONF_DIR "/etc/cgrules.d"
> #define CGRULES_MAX_FIELDS_PER_LINE 3
>
> #define CGROUP_BUFFER_LEN (5 * FILENAME_MAX)
>
>
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