add -u and -g command line args to set user and group.

properly handle portability for mlockall and setrlimit
Tested on linux, Freebsd, solaris, mac.
FSCORE-47

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@6033 d0543943-73ff-0310-b7d9-9358b9ac24b2

configure.in

@@ -170,7 +170,7 @@ AC_SUBST(DYNAMIC_LIB_EXTEN)
 # Checks for header files.
 AC_HEADER_DIRENT
 AC_HEADER_STDC
-AC_CHECK_HEADERS([sys/types.h])
+AC_CHECK_HEADERS([sys/types.h sys/resource.h sched.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
@@ -185,6 +185,59 @@ AC_FUNC_MALLOC
 AC_TYPE_SIGNAL
 AC_FUNC_STRFTIME
 AC_CHECK_FUNCS([gethostname vasprintf mmap mlock mlockall usleep])
+AC_CHECK_FUNCS([sched_setscheduler setpriority setrlimit setgroups initgroups])
+
+AC_CHECK_DECL([RLIMIT_MEMLOCK],
+	[AC_DEFINE([HAVE_RLIMIT_MEMLOCK],[1],[RLIMIT_MEMLOCK constant for setrlimit])],,
+	[#ifdef HAVE_SYS_RESOURCE_H
+	 #include <sys/resource.h>
+	 #endif])
+
+AC_CHECK_DECL([SCHED_RR],
+	[AC_DEFINE([HAVE_SCHED_RR],[1],[SCHED_RR constant for sched_setscheduler])],,
+	[#ifdef HAVE_SCHED_H
+	 #include <sched.h>
+	 #endif])
+
+#
+# use mlockall only on linux (for now; if available)
+#
+if test "x${ac_cv_func_mlockall}" = "xyes"; then
+	AC_MSG_CHECKING([whether to use mlockall])
+	case "$host" in
+	*-linux-*)
+		AC_DEFINE([USE_MLOCKALL],[1],[Enable mlockall support])
+		AC_MSG_RESULT([yes])
+		USE_MLOCKALL=yes
+		;;
+	*-freebsd*)
+		AC_MSG_RESULT([no, broken for non-root users])
+		;;
+	*)
+		AC_MSG_RESULT([no])
+		;;
+	esac
+
+	#
+	# setrlimit prerequisites
+	#
+	if test "x${USE_MLOCKALL}" = "xyes" -a \
+		"x${ac_cv_func_setrlimit}" = "xyes" -a \
+		"x${ac_cv_have_decl_RLIMIT_MEMLOCK}" = "xyes"
+	then
+		AC_DEFINE([USE_SETRLIMIT],[1],[Use setrlimit to disable mlock limit for non-root users])
+	fi
+fi
+
+#
+# sched_setcheduler + round-robin scheduler prerequisites
+#
+if test "x${ac_cv_func_sched_setscheduler}" = "xyes" -a \
+        "x${ac_cv_have_decl_SCHED_RR}" = "xyes"
+then
+	AC_DEFINE([USE_SCHED_SETSCHEDULER],[1],[Enable round-robin scheduler using sched_setscheduler])
+fi
+
 
 AC_C_BIGENDIAN(AC_DEFINE([SWITCH_BYTE_ORDER],__BIG_ENDIAN,[Big Endian]),AC_DEFINE([SWITCH_BYTE_ORDER],__LITTLE_ENDIAN,[Little Endian]))
 

src/include/private/switch_core_pvt.h

@@ -60,6 +60,19 @@ typedef apr_os_thread_t switch_thread_id_t;
 #include <sys/mman.h>
 #endif
 
+#ifndef WIN32
+/* setuid, setgid */
+#include <unistd.h>
+
+/* getgrnam, getpwnam */
+#include <pwd.h>
+#include <grp.h>
+
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+#endif
+
 /* #define DEBUG_ALLOC */
 #define DO_EVENTS
 

src/include/switch_core.h

@@ -1413,6 +1413,18 @@ SWITCH_DECLARE(switch_status_t) switch_core_management_exec(char *relative_oid,
 */
 SWITCH_DECLARE(int32_t) set_high_priority(void);
 
+/*! 
+  \brief Change user and/or group of the running process
+  \long Several possible combinations:
+  - user only (group NULL): switch to user and his primary group (and supplementary groups, if supported)
+  - user and group: switch to user and specified group (only)
+  - group only (user NULL): switch group only
+  \param user name of the user to switch to (or NULL)
+  \param group name of the group to switch to (or NULL)
+  \return 0 on success, -1 otherwise
+*/
+SWITCH_DECLARE(int32_t) change_user_group(const char *user, const char *group);
+
 /*! 
   \brief Run endlessly until the system is shutdown
   \param bg divert console to the background

src/switch.c

@@ -205,6 +205,8 @@ int main(int argc, char *argv[])
 	const char *err = NULL;		/* error value for return from freeswitch initialization */
 #ifndef WIN32
 	int nf = 0;					/* TRUE if we are running in nofork mode */
+	char *runas_user = NULL;
+	char *runas_group = NULL;
 #endif
 	int nc = 0;					/* TRUE if we are running in noconsole mode */
 	FILE *f;					/* file handle to the pid file */
@@ -214,6 +216,7 @@ int main(int argc, char *argv[])
 	char *usageDesc;
 	int alt_dirs = 0;
 	int known_opt;
+ 	int high_prio = 0;
 	switch_core_flag_t flags = SCF_USE_SQL;
 
 #ifdef WIN32
@@ -229,6 +232,8 @@ int main(int argc, char *argv[])
 		"\t-uninstall       -- remove freeswitch as a service\n"
 #else
 		"\t-nf              -- no forking\n"
+		"\t-u [user]        -- specify user to switch to\n"
+		"\t-g [group]       -- specify group to switch to\n"
 #endif
 		"\t-help            -- this message\n"
 		"\t-hp              -- enable high priority settings\n"
@@ -280,6 +285,21 @@ int main(int argc, char *argv[])
 			}
 		}
 #else
+		if (argv[x] && !strcmp(argv[x], "-u")) {
+			x++;
+			if (argv[x] && strlen(argv[x])) {
+				runas_user = argv[x];
+			}
+			known_opt++;
+		}
+
+		if (argv[x] && !strcmp(argv[x], "-g")) {
+			x++;
+			if (argv[x] && strlen(argv[x])) {
+				runas_group = argv[x];
+			}
+			known_opt++;
+		}
 
 		if (argv[x] && !strcmp(argv[x], "-nf")) {
 			nf++;
@@ -287,7 +307,7 @@ int main(int argc, char *argv[])
 		}
 #endif
 		if (argv[x] && !strcmp(argv[x], "-hp")) {
-			set_high_priority();
+			high_prio++;
 			known_opt++;
 		}
 
@@ -389,6 +409,19 @@ int main(int argc, char *argv[])
 #endif
 	}
 
+	if (high_prio) {
+		set_high_priority();
+	}
+
+#ifndef WIN32
+	if (runas_user || runas_group) {
+		if(change_user_group(runas_user, runas_group) < 0) {
+			fprintf(stderr, "Failed to switch user / group\n" );
+			return 255;
+		}
+	}
+#endif
+
 	if (switch_core_init_and_modload(nc ? lfile : NULL, flags, &err) != SWITCH_STATUS_SUCCESS) {
 		fprintf(stderr, "Cannot Initilize [%s]\n", err);
 		return 255;

src/switch_core.c

@@ -360,7 +360,19 @@ SWITCH_DECLARE(void) switch_core_set_globals(void)
 
 SWITCH_DECLARE(int32_t) set_high_priority(void)
 {
-#ifdef __linux__
+#ifdef WIN32
+	SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
+#else
+
+#ifdef USE_SETRLIMIT
+	struct rlimit lim = { RLIM_INFINITY, RLIM_INFINITY };
+#endif
+
+#ifdef USE_SCHED_SETSCHEDULER
+	/*
+	 * Try to use a round-robin scheduler
+	 * with a fallback if that does not work
+	 */
 	struct sched_param sched = { 0 };
 	sched.sched_priority = 1;
 	if (sched_setscheduler(0, SCHED_RR, &sched)) {
@@ -371,19 +383,126 @@ SWITCH_DECLARE(int32_t) set_high_priority(void)
 	}
 #endif
 
-#ifdef WIN32
-	SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
+#ifdef HAVE_SETPRIORITY
+	/*
+	 * setpriority() works on FreeBSD (6.2), nice() doesn't
+	 */
+	if (setpriority(PRIO_PROCESS, getpid(), -10) < 0) {
+		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Could not set nice level\n");
+	}
 #else
-	if(nice(-10)!= -10) {
+	if (nice(-10) != -10) {
 		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Could not set nice level\n");
 	}
 #endif
 
-#define USE_MLOCKALL
-#ifdef HAVE_MLOCKALL
+#ifdef USE_SETRLIMIT
+	/*
+	 * The amount of memory which can be mlocked is limited for non-root users.
+	 * FS will segfault (= hitting the limit) soon after mlockall has been called
+	 * and we've switched to a different user.
+	 * So let's try to remove the mlock limit here...
+	 */
+	if (setrlimit(RLIMIT_MEMLOCK, &lim) < 0) {
+		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT,
+			 "Failed to disable memlock limit, application may crash if run as non-root user!\n");
+	}
+#endif
+
 #ifdef USE_MLOCKALL
+	/*
+	 * Pin memory pages to RAM to prevent being swapped to disk
+	 */
 	mlockall(MCL_CURRENT | MCL_FUTURE);
 #endif
+
+#endif
+	return 0;
+}
+
+SWITCH_DECLARE(int32_t) change_user_group(const char *user, const char *group)
+{
+#ifndef WIN32
+	uid_t runas_uid = 0;
+	gid_t runas_gid = 0;
+	struct passwd *runas_pw = NULL;
+
+	if (user) {
+		/*
+		 * Lookup user information in the system's db
+		 */
+		runas_pw = getpwnam( user );
+		if (!runas_pw) {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Unknown user \"%s\"\n", user);
+			return -1;
+		}
+		runas_uid = runas_pw->pw_uid;
+	}
+
+	if (group) {
+		struct group *gr = NULL;
+
+		/*
+		 * Lookup group information in the system's db
+		 */
+		gr = getgrnam( group );
+		if (!gr) {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Unknown group \"%s\"\n", group);
+			return -1;
+		}
+		runas_gid = gr->gr_gid;
+	}
+
+	if (runas_uid) {
+#ifdef HAVE_SETGROUPS
+		/*
+		 * Drop all group memberships prior to changing anything
+		 * or else we're going to inherit the parent's list of groups
+		 * (which is not what we want...)
+		 */
+		if (setgroups(0, NULL) < 0) {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to drop group access list\n");
+			return -1;
+		}
+#endif
+		if (runas_gid) {
+			/*
+			 * A group has been passed, switch to it
+			 * (without loading the user's other groups)
+			 */
+			if (setgid(runas_gid) < 0) {
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to change gid!\n");
+				return -1;
+			}
+		} else {
+			/*
+			 * No group has been passed, use the user's primary group in this case
+			 */
+			if (setgid(runas_pw->pw_gid) < 0) {
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to change gid!\n");
+				return -1;
+			}
+
+#ifdef HAVE_INITGROUPS
+			/*
+			 * Set all the other groups the user is a member of
+			 * (This can be really useful for fine-grained access control)
+			 */
+			if (initgroups(runas_pw->pw_name, runas_pw->pw_gid) < 0) {
+				switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to set group access list for user\n");
+				return -1;
+			}
+#endif
+		}
+
+		/*
+		 * Finally drop all privileges by switching to the new userid
+		 */
+		if (setuid(runas_uid) < 0) {
+			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to change uid!\n");
+			return -1;
+		}
+	}
 #endif
 	return 0;
 }