The current behaviour of batmand is to detach to background by default when no debug mode is activated. This is problematic on different libc implementations which don't support to use pthreads after the usage of fork without calling exec* first. They will allow batmand to fork to the background, but freeze the batmand main thread after calling pthread_create. This patch adds a parameter to change the behaviour to not fork to the background. It can be used to fork to the background from the outside and workaround the fork+thread issue by setting this parameter. Example usage is to call batmand using batmand -D tap1 > /dev/null 2>&1 & or start-stop-daemon --start --background --exec /usr/sbin/batmand -- -D wlan0

Signed-off-by: Sven Eckelmann sven.eckelmann@gmx.de --- batman/batman.c | 2 ++ batman/man/batmand.8 | 3 +++ batman/posix/init.c | 11 ++++++++--- 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/batman/batman.c b/batman/batman.c index 73214ac..d05833e 100644 --- a/batman/batman.c +++ b/batman/batman.c @@ -138,6 +138,7 @@ void usage(void) fprintf( stderr, " -b run connection in batch mode\n" ); fprintf( stderr, " -c connect via unix socket\n" ); fprintf( stderr, " -d debug level\n" ); + fprintf( stderr, " -B don't run daemon in the background\n" ); fprintf( stderr, " -g gateway class\n" ); fprintf( stderr, " -h this help\n" ); fprintf( stderr, " -H verbose help\n" ); @@ -168,6 +169,7 @@ void verbose_usage(void) fprintf( stderr, " 2 -> list gateways\n" ); fprintf( stderr, " 3 -> observe batman\n" ); fprintf( stderr, " 4 -> observe batman (very verbose)\n\n" ); + fprintf( stderr, " -D not detach and doesn't run as daemon in the background\n" );

if ( debug_level_max == 5 ) fprintf( stderr, " 5 -> memory debug / cpu usage\n\n" ); diff --git a/batman/man/batmand.8 b/batman/man/batmand.8 index 263b4c3..07f6300 100644 --- a/batman/man/batmand.8 +++ b/batman/man/batmand.8 @@ -61,6 +61,9 @@ allowed values: 1 -> list neighbors Note that debug level 5 can be disabled at compile time. .RE .TP +.B -D don't run daemon in the background +When this option is specified, batmand will not detach and does not become a daemon. +.TP .B -g gateway class The gateway class is used to tell other nodes in the network your available internet bandwidth. Just enter any number (optionally followed by "kbit" or "mbit") and the daemon will guess your appropriate gateway class. Use "/" to seperate the down- and upload rates. You can omit the upload rate and batmand will assume an upload of download / 5. .RS 17 diff --git a/batman/posix/init.c b/batman/posix/init.c index b0ef71d..bd10438 100644 --- a/batman/posix/init.c +++ b/batman/posix/init.c @@ -229,7 +229,7 @@ void apply_init_args( int argc, char *argv[] ) { struct debug_level_info *debug_level_info; struct list_head *list_pos, *list_pos_tmp; uint8_t found_args = 1, batch_mode = 0, info_output = 0, was_hna = 0; - int8_t res; + int8_t res, no_detach = 0;

int32_t optchar, option_index, recv_buff_len, bytes_written, download_speed = 0, upload_speed = 0; char str1[16], str2[16], *slash_ptr, *unix_buff, *buff_ptr, *cr_ptr; @@ -253,7 +253,7 @@ void apply_init_args( int argc, char *argv[] ) { if ( strstr( SOURCE_VERSION, "-" ) != NULL ) printf( "WARNING: You are using the unstable batman branch. If you are interested in *using* batman get the latest stable release !\n" );

- while ( ( optchar = getopt_long( argc, argv, "a:A:bcd:hHio:g:p:r:s:vV", long_options, &option_index ) ) != -1 ) { + while ( ( optchar = getopt_long( argc, argv, "a:A:bcd:DhHio:g:p:r:s:vV", long_options, &option_index ) ) != -1 ) {

switch ( optchar ) {

@@ -306,6 +306,11 @@ void apply_init_args( int argc, char *argv[] ) { found_args += ((*((char*)( optarg - 1)) == optchar) ? 1 : 2); break;

+ case 'D': + no_detach++; + found_args++; + break; + case 'g':

if ( ( slash_ptr = strchr( optarg, '/' ) ) != NULL ) @@ -647,7 +652,7 @@ void apply_init_args( int argc, char *argv[] ) { /* daemonize */ if (debug_level == 0) {

- if (my_daemon() < 0) { + if (no_detach == 0 && my_daemon() < 0) {

printf("Error - can't fork to background: %s\n", strerror(errno)); restore_defaults();

uclibc >=0.9.29 doesn't support threads after the call of fork in linuxthreads mode without calling exec* first. We can now try to call the binary again with execv to sanitise the current process and tell him that he should not try to get into the daemon mode so we don't recursive call batmand again. This can fail when no linux procfs is mounted on /proc or /proc/self/exe is a dangling symlink. In this case we continue without any changes.

Signed-off-by: Sven Eckelmann sven.eckelmann@gmx.de --- batman/posix/init.c | 97 ++++++++++++++++++++++++++++++++------------------ 1 files changed, 62 insertions(+), 35 deletions(-)

diff --git a/batman/posix/init.c b/batman/posix/init.c index bd10438..648ebd7 100644 --- a/batman/posix/init.c +++ b/batman/posix/init.c @@ -46,7 +46,28 @@ int8_t stop;

-static int my_daemon(void) { +static void reexecute(int argc, char *argv[]) +{ + char ** new_argv = NULL; + char* no_detach_flag = "-D"; + int i; + + new_argv = debugMalloc( sizeof(char *const) * (argc + 2), 5005 ); + for (i = 0; i < argc; i++ ) { + new_argv[i] = argv[i]; + } + new_argv[argc] = no_detach_flag; + new_argv[argc + 1] = NULL; + + + execv("/proc/self/exe", new_argv); + + /* execv can fail due to different reasons + so we must be able to continue here */ + debugFree(new_argv, 5005); +} + +static int my_daemon(int argc, char *argv[]) {

int fd;

@@ -83,6 +104,9 @@ static int my_daemon(void) {

}

+ /* Try to restart batmand in daemon mode to be sure that it is sanitised */ + reexecute(argc, argv); + return 0;

} @@ -228,7 +252,7 @@ void apply_init_args( int argc, char *argv[] ) { struct hna_node *hna_node; struct debug_level_info *debug_level_info; struct list_head *list_pos, *list_pos_tmp; - uint8_t found_args = 1, batch_mode = 0, info_output = 0, was_hna = 0; + uint8_t found_args = 1, batch_mode = 0, info_output = 0, was_hna = 0, i; int8_t res, no_detach = 0;

int32_t optchar, option_index, recv_buff_len, bytes_written, download_speed = 0, upload_speed = 0; @@ -572,14 +596,44 @@ void apply_init_args( int argc, char *argv[] ) { if ( flush_routes_rules(1) < 0 ) exit(EXIT_FAILURE);

+ + for (i = found_args; i < argc; i++) { + if (argv[i][0] == '-') { + fprintf(stderr, "%s: invalid option -- %s\n", argv[0], argv[i]); + usage(); + exit(EXIT_FAILURE); + } + } + + /* daemonize */ + if (debug_level == 0) { + + if (no_detach == 0 && my_daemon(argc, argv) < 0) { + + printf("Error - can't fork to background: %s\n", strerror(errno)); + restore_defaults(); + exit(EXIT_FAILURE); + + } + + openlog("batmand", LOG_PID, LOG_DAEMON); + + } else { + + printf("B.A.T.M.A.N. %s%s (compatibility version %i)\n", SOURCE_VERSION, (strlen(REVISION_VERSION) > 3 ? REVISION_VERSION : ""), COMPAT_VERSION); + + debug_clients.clients_num[ debug_level - 1 ]++; + debug_level_info = debugMalloc( sizeof(struct debug_level_info), 205 ); + INIT_LIST_HEAD( &debug_level_info->list ); + debug_level_info->fd = 2; + list_add( &debug_level_info->list, (struct list_head_first *)debug_clients.fd_list[debug_level - 1] ); + + } + + log_facility_active = 1; + while (argc > found_args) {

- if (argv[found_args][0] == '-') { - fprintf(stderr, "%s: invalid option -- %s\n", argv[0], argv[found_args]); - usage(); - exit(EXIT_FAILURE); - } - batman_if = debugMalloc( sizeof(struct batman_if), 206 ); memset( batman_if, 0, sizeof(struct batman_if) ); INIT_LIST_HEAD( &batman_if->list ); @@ -649,33 +703,6 @@ void apply_init_args( int argc, char *argv[] ) {

}

- /* daemonize */ - if (debug_level == 0) { - - if (no_detach == 0 && my_daemon() < 0) { - - printf("Error - can't fork to background: %s\n", strerror(errno)); - restore_defaults(); - exit(EXIT_FAILURE); - - } - - openlog("batmand", LOG_PID, LOG_DAEMON); - - } else { - - printf("B.A.T.M.A.N. %s%s (compatibility version %i)\n", SOURCE_VERSION, (strlen(REVISION_VERSION) > 3 ? REVISION_VERSION : ""), COMPAT_VERSION); - - debug_clients.clients_num[ debug_level - 1 ]++; - debug_level_info = debugMalloc( sizeof(struct debug_level_info), 205 ); - INIT_LIST_HEAD( &debug_level_info->list ); - debug_level_info->fd = 2; - list_add( &debug_level_info->list, (struct list_head_first *)debug_clients.fd_list[debug_level - 1] ); - - } - - log_facility_active = 1; - pthread_create( &unix_if.listen_thread_id, NULL, &unix_listen, NULL );

/* add rule for hna networks */