Fix #45: add support for rlimit per service/run/task/inetd/tty

This patch extends the existing rlimit implementation to support setting
limits per service, run/task, inetd, and tty.

Use rlimit in /etc/finit.conf to change the global setting, which is
then inherited to each /etc/finit.d/*.conf.  For each .conf file the
rlimit is reinitialized to the global finit.conf settings.

Also, add `unlimited` keyword, to replace the now deprecated `infinity`
keyword.  The latter is however kept, for compatibility with previous
releases, for the foreseeable future.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

doc/config.md

@@ -51,12 +51,15 @@ Syntax
 * `network <PATH>`  
   Script or program to bring up networking, with optional arguments
 
-* `rlimit <hard|soft> RESOURCE <LIMIT|infinity>`  
+* `rlimit <hard|soft> RESOURCE <LIMIT|unlimited>`  
   Set the hard or soft limit for a resource.  `RESOURCE` is a lower-case
   string matching the `RLIMIT_` constants from `setrlimit(2)`, without
-  the prefix.  E.g. to set `RLIMIT_CPU`, use `cpu`.  The limit is an
-  integer that depends on the resource being modified, see the man page
-  for more information.  The special limit `infinity` means unlimited.
+  the prefix.  E.g. to set `RLIMIT_CPU`, use `cpu`.
+  
+  The limit is an integer that depends on the resource being modified,
+  see the man page, or the kernel `/proc/PID/limits` file, for more
+  information.  Finit versions before v3.1 used `infinity` for
+  `unlimited`, which is still a supported keyword.
 
 ```shell
         # No process is allowed more than 8MB of address space

plugins/dbus.c

@@ -29,6 +29,7 @@
 #include "helpers.h"
 #include "plugin.h"
 #include "service.h"
+#include "conf.h"
 
 #define DAEMON "dbus-daemon"
 #define ARGS   "--nofork --system"
@@ -58,7 +59,7 @@ static void setup(void *arg)
 
 	/* Register service with Finit */
 	snprintf(line, sizeof(line), "[S12345] %s %s -- %s", cmd, ARGS, DESC);
-	if (service_register(SVC_TYPE_SERVICE, line, NULL))
+	if (service_register(SVC_TYPE_SERVICE, line, global_rlimit, NULL))
 		_pe("Failed registering %s", DAEMON);
 	free(cmd);
 

src/conf.c

@@ -38,6 +38,7 @@
 #define MATCH_CMD(l, c, x) \
 	(!strncasecmp(l, c, strlen(c)) && (x = (l) + strlen(c)))
 
+struct rlimit global_rlimit[RLIMIT_NLIMITS];
 static int parse_conf(char *file);
 
 
@@ -163,59 +164,74 @@ static const struct rlimit_name rlimit_names[] = {
 	{ NULL, 0 }
 };
 
-void conf_parse_rlimit(char *line)
+int str2rlim(char *str)
 {
-	struct rlimit rlim;
-	rlim_t cfg, *set;
-	const struct rlimit_name *name;
+	const struct rlimit_name *rn;
+
+	for (rn = rlimit_names; rn->name; rn++) {
+		if (!strcmp(str, rn->name))
+			return rn->val;
+	}
+
+	return -1;
+}
+
+char *rlim2str(int rlim)
+{
+	const struct rlimit_name *rn;
+
+	for (rn = rlimit_names; rn->name; rn++) {
+		if (rn->val == rlim)
+			return rn->name;
+	}
+
+	return "unknown";
+}
+
+void conf_parse_rlimit(char *line, struct rlimit arr[])
+{
+	char *level, *limit, *val;
 	int resource = -1;
+	rlim_t cfg, *set;
 
-	char *tok = strtok(line, " \t");
+	level = strtok(line, " \t");
+	if (!level)
+		goto error;
 
-	if (tok && !strcmp(tok, "soft"))
-		set = &rlim.rlim_cur;
-	else if (tok && !strcmp(tok, "hard"))
-		set = &rlim.rlim_max;
+	limit = strtok(NULL, " \t");
+	if (!limit)
+		goto error;
+
+	resource = str2rlim(limit);
+	if (resource < 0 || resource > RLIMIT_NLIMITS)
+		goto error;
+
+	val = strtok(NULL, " \t");
+	if (!val)
+		goto error;
+
+	if (!strcmp(level, "soft"))
+		set = &arr[resource].rlim_cur;
+	else if (!strcmp(level, "hard"))
+		set = &arr[resource].rlim_max;
 	else
 		goto error;
 
-	tok = strtok(NULL, " \t");
-	if (!tok)
-		goto error;
-
-	for (name = rlimit_names; name->name; name++) {
-		if (!strcmp(tok, name->name))
-			resource = name->val;
-	}
-
-	if (resource < 0)
-		goto fail;
-
-	tok = strtok(NULL, " \t");
-	if (!tok)
-		goto fail;
-
-	if (!strcmp(tok, "infinity")) {
+	/* Official keyword from v3.1 is `unlimited`, from prlimit(1) */
+	if (!strcmp(val, "unlimited") || !strcmp(val, "infinity")) {
 		cfg = RLIM_INFINITY;
 	} else {
 		const char *err = NULL;
 
-		cfg = strtonum(tok, 0, (long long)2 << 31, &err);
-		if (err)
-			goto fail;
+		cfg = strtonum(val, 0, (long long)2 << 31, &err);
+		if (err) {
+			logit(LOG_WARNING, "rlimit: invalid %s value: %s",
+			      rlim2str(resource), val);
+			return;
+		}
 	}
 
-	if (getrlimit(resource, &rlim))
-		goto fail;
-
 	*set = cfg;
-	if (setrlimit(resource, &rlim))
-		goto fail;
-
-	return;
-
-fail:
-	logit(LOG_WARNING, "rlimit: Failed setting rlimit %s", name->name ? : "unknown");
 	return;
 error:
 	logit(LOG_WARNING, "rlimit: parse error");
@@ -289,7 +305,7 @@ static void parse_static(char *line)
 	}
 }
 
-static void parse_dynamic(char *line, struct timeval *mtime)
+static void parse_dynamic(char *line, struct rlimit rlimit[], struct timeval *mtime)
 {
 	char *x;
 	char cmd[CMD_SIZE];
@@ -315,26 +331,26 @@ static void parse_dynamic(char *line, struct timeval *mtime)
 
 	/* Monitored daemon, will be respawned on exit */
 	if (MATCH_CMD(line, "service ", x)) {
-		service_register(SVC_TYPE_SERVICE, x, mtime);
+		service_register(SVC_TYPE_SERVICE, x, rlimit, mtime);
 		return;
 	}
 
 	/* One-shot task, will not be respawned */
 	if (MATCH_CMD(line, "task ", x)) {
-		service_register(SVC_TYPE_TASK, x, mtime);
+		service_register(SVC_TYPE_TASK, x, rlimit, mtime);
 		return;
 	}
 
 	/* Like task but waits for completion, useful w/ [S] */
 	if (MATCH_CMD(line, "run ", x)) {
-		service_register(SVC_TYPE_RUN, x, mtime);
+		service_register(SVC_TYPE_RUN, x, rlimit, mtime);
 		return;
 	}
 
 	/* Classic inetd service */
 	if (MATCH_CMD(line, "inetd ", x)) {
 #ifdef INETD_ENABLED
-		service_register(SVC_TYPE_INETD, x, mtime);
+		service_register(SVC_TYPE_INETD, x, rlimit, mtime);
 #else
 		_e("Finit built with inetd support disabled, cannot register service inetd %s!", x);
 #endif
@@ -343,13 +359,13 @@ static void parse_dynamic(char *line, struct timeval *mtime)
 
 	/* Read resource limits */
 	if (MATCH_CMD(line, "rlimit ", x)) {
-		conf_parse_rlimit(x);
+		conf_parse_rlimit(x, rlimit);
 		return;
 	}
 
 	/* Regular or serial TTYs to run getty */
 	if (MATCH_CMD(line, "tty ", x)) {
-		tty_register(strip_line(x), mtime);
+		tty_register(strip_line(x), rlimit, mtime);
 		return;
 	}
 }
@@ -368,6 +384,7 @@ static void tabstospaces(char *line)
 static int parse_conf_dynamic(char *file, struct timeval *mtime)
 {
 	FILE *fp;
+	struct rlimit rlimit[RLIMIT_NLIMITS];
 
 	fp = fopen(file, "r");
 	if (!fp) {
@@ -375,6 +392,9 @@ static int parse_conf_dynamic(char *file, struct timeval *mtime)
 		return 1;
 	}
 
+	/* Prepare default limits for each service */
+	memcpy(rlimit, global_rlimit, sizeof(rlimit));
+
 	_d("Parsing %s", file);
 	while (!feof(fp)) {
 		char line[LINE_SIZE] = "";
@@ -386,7 +406,7 @@ static int parse_conf_dynamic(char *file, struct timeval *mtime)
 		tabstospaces(line);
 		_d("%s", line);
 
-		parse_dynamic(line, mtime);
+		parse_dynamic(line, rlimit, mtime);
 	}
 
 	fclose(fp);
@@ -394,11 +414,19 @@ static int parse_conf_dynamic(char *file, struct timeval *mtime)
 	return 0;
 }
 
+/* Reads /etc/finit.conf, once at boot */
 static int parse_conf(char *file)
 {
 	FILE *fp;
 	char line[LINE_SIZE] = "";
-	char *x;
+
+	/*
+	 * Get current global limits, which may be overridden from both
+	 * finit.conf, for Finit and its services like inetd+getty, and
+	 * *.conf in finit.d/, for each service(s) listed there.
+	 */
+	for (int i = 0; i < RLIMIT_NLIMITS; i++)
+		getrlimit(i, &global_rlimit[i]);
 
 	fp = fopen(file, "r");
 	if (!fp)
@@ -414,11 +442,17 @@ static int parse_conf(char *file)
 		_d("%s", line);
 
 		parse_static(line);
-		parse_dynamic(line, NULL);
+		parse_dynamic(line, global_rlimit, NULL);
 	}
 
 	fclose(fp);
 
+	/* Set global limits */
+	for (int i = 0; i < RLIMIT_NLIMITS; i++) {
+		if (setrlimit(i, &global_rlimit[i]) == -1)
+			logit(LOG_WARNING, "rlimit: Failed setting %s", rlim2str(i));
+	}
+
 	return 0;
 }
 
@@ -439,6 +473,10 @@ int conf_reload_dynamic(void)
 		return 1;
 	}
 
+	/* Update global limits in case operator used prlimit(1) on us */
+	for (i = 0; i < RLIMIT_NLIMITS; i++)
+		getrlimit(i, &global_rlimit[i]);
+
 	for (i = 0; i < num; i++) {
 		char *name = e[i]->d_name;
 		char  path[LINE_SIZE];

src/conf.h

@@ -26,6 +26,11 @@
 
 #include "svc.h"
 
+extern struct rlimit global_rlimit[];
+
+int   str2rlim(char *str);
+char *rlim2str(int rlim);
+
 void conf_parse_cmdline   (void);
 int  conf_parse_runlevels (char *runlevels);
 void conf_parse_cond      (svc_t *svc, char *cond);

src/exec.c

@@ -234,7 +234,7 @@ int exec_runtask(char *cmd, char *args[])
 	return execvp(_PATH_BSHELL, argv);
 }
 
-static void prepare_tty(char *tty, speed_t speed, char *procname)
+static void prepare_tty(char *tty, speed_t speed, char *procname, struct rlimit rlimit[])
 {
 	struct sigaction sa;
 	struct termios term;
@@ -270,6 +270,12 @@ static void prepare_tty(char *tty, speed_t speed, char *procname)
 	sigaction(SIGINT,  &sa, NULL);
 	sigaction(SIGQUIT, &sa, NULL);
 
+	/* Set configured limits */
+	for (int i = 0; i < RLIMIT_NLIMITS; i++) {
+		if (setrlimit(i, &rlimit[i]) == -1)
+			logit(LOG_WARNING, "%s: rlimit: Failed setting %s", tty, rlim2str(i));
+	}
+
 	/* Create new session and process group */
 	setsid();
 
@@ -348,7 +354,7 @@ static int activate_console(int noclear, int nowait)
  * since /bin/login usually only disables ECHO until a password line has
  * been entered.  Upon starting the user's $SHELL the ISIG flag is reset
  */
-pid_t run_getty(char *tty, char *baud, char *term, int noclear, int nowait)
+pid_t run_getty(char *tty, char *baud, char *term, int noclear, int nowait, struct rlimit rlimit[])
 {
 	pid_t pid;
 
@@ -362,7 +368,7 @@ pid_t run_getty(char *tty, char *baud, char *term, int noclear, int nowait)
 				logit(LOG_CRIT, "TTY %s: Invalid speed %s", tty, baud);
 		}
 
-		prepare_tty(tty, speed, "finit-getty");
+		prepare_tty(tty, speed, "finit-getty", rlimit);
 		if (activate_console(noclear, nowait))
 			_exit(getty(tty, speed, term, NULL));
 	}
@@ -370,7 +376,7 @@ pid_t run_getty(char *tty, char *baud, char *term, int noclear, int nowait)
 	return pid;
 }
 
-pid_t run_getty2(char *tty, char *cmd, char *args[], int noclear, int nowait)
+pid_t run_getty2(char *tty, char *cmd, char *args[], int noclear, int nowait, struct rlimit rlimit[])
 {
 	pid_t pid;
 
@@ -400,7 +406,7 @@ pid_t run_getty2(char *tty, char *cmd, char *args[], int noclear, int nowait)
 		dup2(fd, STDERR_FILENO);
 
 		/* Dunno speed, tell stty() to not mess with it */
-		prepare_tty(tty, B0, "getty");
+		prepare_tty(tty, B0, "getty", rlimit);
 
 		if (ioctl(STDIN_FILENO, TIOCSCTTY, 1) < 0)
 			_pe("Failed TIOCSCTTY");

src/finit.c

@@ -357,7 +357,7 @@ int main(int argc, char* argv[])
 
 			/* Register udevd as a monitored service, started much later */
 			snprintf(cmd, sizeof(cmd), "[12345] %s -- Device event manager daemon", path);
-			if (service_register(SVC_TYPE_SERVICE, cmd, NULL)) {
+			if (service_register(SVC_TYPE_SERVICE, cmd, global_rlimit, NULL)) {
 				_pe("Failed registering %s", path);
 				udev = 0;
 			}

src/helpers.h

@@ -26,6 +26,7 @@
 #define FINIT_HELPERS_H_
 
 #include <stdarg.h>
+#include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/ttydefaults.h>	/* Not included by default in musl libc */
 #include <termios.h>
@@ -71,8 +72,8 @@ int     complete        (char *cmd, int pid);
 int     run             (char *cmd);
 int     run_interactive (char *cmd, char *fmt, ...);
 int     exec_runtask    (char *cmd, char *args[]);
-pid_t   run_getty       (char *tty, char *baud, char *term,  int noclear, int nowait);
-pid_t   run_getty2      (char *tty, char *cmd, char *args[], int noclear, int nowait);
+pid_t   run_getty       (char *tty, char *baud, char *term,  int noclear, int nowait, struct rlimit rlimit[]);
+pid_t   run_getty2      (char *tty, char *cmd, char *args[], int noclear, int nowait, struct rlimit rlimit[]);
 int     run_parts       (char *dir, char *cmd);
 
 static inline void create(char *path, mode_t mode, uid_t uid, gid_t gid)

src/service.c

@@ -26,6 +26,7 @@
 
 #include <ctype.h>		/* isblank() */
 #include <string.h>
+#include <sys/resource.h>
 #include <sys/wait.h>
 #include <net/if.h>
 #include <lite/lite.h>
@@ -192,6 +193,14 @@ static int service_start(svc_t *svc)
 #endif
 		char *args[MAX_NUM_SVC_ARGS];
 
+		/* Set configured limits */
+		for (int i = 0; i < RLIMIT_NLIMITS; i++) {
+			if (setrlimit(i, &svc->rlimit[i]) == -1)
+				logit(LOG_WARNING,
+				      "%s: rlimit: Failed setting %s",
+				      svc->cmd, rlim2str(i));
+		}
+
 		/* Set desired user+group */
 		if (gid >= 0)
 			setgid(gid);
@@ -471,9 +480,10 @@ void service_runlevel(int newlevel)
 
 /**
  * service_register - Register service, task or run commands
- * @type:     %SVC_TYPE_SERVICE(0), %SVC_TYPE_TASK(1), %SVC_TYPE_RUN(2)
- * @svcline:  A complete command line with -- separated description text
- * @mtime:    The modification time if service is loaded from /etc/finit.d
+ * @type:   %SVC_TYPE_SERVICE(0), %SVC_TYPE_TASK(1), %SVC_TYPE_RUN(2)
+ * @cfg:    Configuration, complete command, with -- for description text
+ * @rlimit: Limits for this service/task/run/inetd, may be global limits
+ * @mtime:  The modification time if service is loaded from /etc/finit.d
  *
  * This function is used to register commands to be run on different
  * system runlevels with optional username.  The @type argument details
@@ -520,7 +530,7 @@ void service_runlevel(int newlevel)
  * Returns:
  * POSIX OK(0) on success, or non-zero errno exit status on failure.
  */
-int service_register(int type, char *svcline, struct timeval *mtime)
+int service_register(int type, char *cfg, struct rlimit rlimit[], struct timeval *mtime)
 {
 	int i = 0;
 	int id = 1;		/* Default to ID:1 */
@@ -534,12 +544,12 @@ int service_register(int type, char *svcline, struct timeval *mtime)
 	svc_t *svc;
 	plugin_t *plugin = NULL;
 
-	if (!svcline) {
+	if (!cfg) {
 		_e("Invalid input argument");
 		return errno = EINVAL;
 	}
 
-	line = strdup(svcline);
+	line = strdup(cfg);
 	if (!line)
 		return 1;
 
@@ -555,7 +565,7 @@ int service_register(int type, char *svcline, struct timeval *mtime)
 	cmd = strtok(line, " ");
 	if (!cmd) {
 	incomplete:
-		_e("Incomplete service '%s', cannot register", svcline);
+		_e("Incomplete service '%s', cannot register", cfg);
 		free(line);
 		return errno = ENOENT;
 	}
@@ -718,6 +728,8 @@ recreate:
 		}
 	}
 #endif
+	/* Set configured limits */
+	memcpy(svc->rlimit, rlimit, sizeof(svc->rlimit));
 
 	/* New, recently modified or unchanged ... used on reload. */
 	svc_check_dirty(svc, mtime);

src/service.h

@@ -28,7 +28,7 @@
 #include "svc.h"
 
 void	  service_runlevel	 (int newlevel);
-int	  service_register	 (int type, char *line, struct timeval *mtime);
+int	  service_register	 (int type, char *line, struct rlimit rlimit[], struct timeval *mtime);
 void      service_unregister     (svc_t *svc);
 int       service_enabled	 (svc_t *svc);
 

src/svc.h

@@ -26,6 +26,7 @@
 #define FINIT_SVC_H_
 
 #include <sys/ipc.h>		/* IPC_CREAT */
+#include <sys/resource.h>
 #include <sys/shm.h>		/* shmat() */
 #include <sys/types.h>		/* pid_t */
 #include <lite/lite.h>
@@ -84,6 +85,9 @@ typedef struct svc {
 	/* Instance specifics */
 	int            job, id;	       /* JOB:ID */
 
+	/* Limits and scoping */
+	struct rlimit  rlimit[RLIMIT_NLIMITS];
+
 	/* Service details */
 	pid_t	       pid;
 	const svc_state_t state;       /* Paused, Reloading, Restart, Running, ... */

src/tty.c

@@ -127,8 +127,9 @@ void tty_sweep(void)
 
 /**
  * tty_register - Register a getty on a device
- * @line:  Configuration, text after initial "tty"
- * @mtime: Modification time, to propagate to lower layers
+ * @line:   Configuration, text after initial "tty"
+ * @rlimit: Limits for this service/task/run/inetd, may be global limits
+ * @mtime:  Modification time, to propagate to lower layers
  *
  * A Finit tty line can use the internal getty implementation or an
  * external one, like the BusyBox getty for instance.  This function
@@ -146,7 +147,7 @@ void tty_sweep(void)
  * Different getty implementations prefer the TTY device argument in
  * different order, so take care to investigate this first.
  */
-int tty_register(char *line, struct timeval *mtime)
+int tty_register(char *line, struct rlimit rlimit[], struct timeval *mtime)
 {
 	tty_node_t *entry;
 	int         insert = 0, noclear = 0, nowait = 0;
@@ -278,6 +279,9 @@ int tty_register(char *line, struct timeval *mtime)
 	if (insert)
 		LIST_INSERT_HEAD(&tty_list, entry, link);
 
+	/* Register configured limits */
+	memcpy(entry->data.rlimit, rlimit, sizeof(entry->data.rlimit));
+
 	tty_check(entry, mtime);
 	_d("TTY %s is %sdirty", dev, entry->dirty ? "" : "NOT ");
 
@@ -399,9 +403,9 @@ void tty_start(finit_tty_t *tty)
 	}
 
 	if (!tty->cmd)
-		tty->pid = run_getty(dev, tty->baud, tty->term, tty->noclear, tty->nowait);
+		tty->pid = run_getty(dev, tty->baud, tty->term, tty->noclear, tty->nowait, tty->rlimit);
 	else
-		tty->pid = run_getty2(dev, tty->cmd, tty->args, tty->noclear, tty->nowait);
+		tty->pid = run_getty2(dev, tty->cmd, tty->args, tty->noclear, tty->nowait, tty->rlimit);
 }
 
 void tty_stop(finit_tty_t *tty)

src/tty.h

@@ -26,6 +26,7 @@
 #define FINIT_TTY_H_
 
 #include <limits.h>
+#include <sys/resource.h>
 #include <lite/queue.h>		/* BSD sys/queue.h API */
 
 #define TTY_MAX_ARGS 16
@@ -43,6 +44,9 @@ typedef struct {
 	char  *args[TTY_MAX_ARGS];
 
 	int    pid;
+
+	/* Limits and scoping */
+	struct rlimit rlimit[RLIMIT_NLIMITS];
 } finit_tty_t;
 
 typedef struct tty_node {
@@ -61,7 +65,7 @@ void	    tty_mark	    (void);
 void	    tty_check	    (tty_node_t *tty, struct timeval *mtime);
 void	    tty_sweep	    (void);
 
-int	    tty_register    (char *line, struct timeval *mtime);
+int	    tty_register    (char *line, struct rlimit rlimit[], struct timeval *mtime);
 int	    tty_unregister  (tty_node_t *tty);
 
 tty_node_t *tty_find	    (char *dev);