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Big refactor: Add request cache and collector

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This commit is contained in:
topjohnwu 2017-05-29 18:54:33 +08:00
parent 3395c84560
commit 48ace3de57
6 changed files with 314 additions and 212 deletions
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4
activity.c
View File

@ -54,13 +54,13 @@ static int setup_user(struct su_context *ctx, char* user) {
void app_send_result(struct su_context *ctx, policy_t policy) {
char fromUid[16];
sprintf(fromUid, "%d", ctx->from.uid);
sprintf(fromUid, "%d", ctx->info->uid);
char toUid[16];
sprintf(toUid, "%d", ctx->to.uid);
char pid[16];
sprintf(pid, "%d", ctx->from.pid);
sprintf(pid, "%d", ctx->info->pid);
char user[16];
int notify = setup_user(ctx, user);

53
db.c
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@ -9,67 +9,56 @@
#include <sqlite3.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
#include "magisk.h"
#include "su.h"
struct callback_data_t {
struct su_context *ctx;
policy_t policy;
};
static int database_callback(void *v, int argc, char **argv, char **azColName){
struct callback_data_t *data = (struct callback_data_t *)v;
policy_t policy = INTERACTIVE;
int i;
static int database_callback(void *v, int argc, char **argv, char **azColName) {
struct su_context *ctx = (struct su_context *) v;
policy_t policy = QUERY;
time_t until = 0;
for(i = 0; i < argc; i++) {
for(int i = 0; i < argc; i++) {
if (strcmp(azColName[i], "policy") == 0) {
if (argv[i] != NULL) {
policy = atoi(argv[i]);
}
}
else if (strcmp(azColName[i], "until") == 0) {
} else if (strcmp(azColName[i], "until") == 0) {
if (argv[i] != NULL) {
until = atol(argv[i]);
}
}
}
if (policy == DENY) {
data->policy = DENY;
return -1;
} else if (policy == ALLOW && (until == 0 || until > time(NULL))) {
data->policy = ALLOW;
// even though we allow, continue, so we can see if there's another policy
// that denies...
}
if (policy == DENY)
ctx->info->policy = DENY;
else if (policy == ALLOW && (until == 0 || until > time(NULL)))
ctx->info->policy = ALLOW;
return 0;
}
policy_t database_check(struct su_context *ctx) {
void database_check(struct su_context *ctx) {
sqlite3 *db = NULL;
// Check if file is readable
if (access(ctx->user.database_path, R_OK) == -1)
return;
char query[512];
snprintf(query, sizeof(query), "select policy, until from policies where uid=%d", ctx->from.uid);
snprintf(query, sizeof(query), "SELECT policy, until FROM policies WHERE uid=%d", ctx->info->uid % 100000);
int ret = sqlite3_open_v2(ctx->user.database_path, &db, SQLITE_OPEN_READONLY, NULL);
if (ret) {
LOGE("sqlite3 open failure: %d", ret);
LOGD("sqlite3 open failure: %s\n", sqlite3_errstr(ret));
sqlite3_close(db);
return INTERACTIVE;
return;
}
char *err = NULL;
struct callback_data_t data;
data.ctx = ctx;
data.policy = INTERACTIVE;
ret = sqlite3_exec(db, query, database_callback, &data, &err);
ret = sqlite3_exec(db, query, database_callback, ctx, &err);
sqlite3_close(db);
if (err != NULL) {
LOGE("sqlite3_exec: %s", err);
return DENY;
LOGE("sqlite3_exec: %s\n", err);
ctx->info->policy = DENY;
}
return data.policy;
}

190
su.c
View File

@ -27,7 +27,7 @@
#include "resetprop.h"
#include "su.h"
static struct su_context *su_ctx;
struct su_context *su_ctx;
static void usage(int status) {
FILE *stream = (status == EXIT_SUCCESS) ? stdout : stderr;
@ -46,7 +46,7 @@ static void usage(int status) {
" -v, --version display version number and exit\n"
" -V display version code and exit,\n"
" this is used almost exclusively by Superuser.apk\n");
exit(status);
exit2(status);
}
static char *concat_commands(int argc, char *argv[]) {
@ -61,16 +61,6 @@ static char *concat_commands(int argc, char *argv[]) {
return strdup(command);
}
static int get_multiuser_mode() {
char *prop = getprop(MULTIUSER_MODE_PROP);
if (prop) {
int ret = atoi(prop);
free(prop);
return ret;
}
return MULTIUSER_MODE_OWNER_ONLY;
}
static void populate_environment(const struct su_context *ctx) {
struct passwd *pw;
@ -96,8 +86,7 @@ static __attribute__ ((noreturn)) void allow() {
umask(su_ctx->umask);
// no need to log if called by root
if (su_ctx->from.uid != UID_ROOT)
if (su_ctx->notify)
app_send_result(su_ctx, ALLOW);
char *binary = su_ctx->to.shell;
@ -129,11 +118,10 @@ static __attribute__ ((noreturn)) void allow() {
}
static __attribute__ ((noreturn)) void deny() {
// no need to log if called by root
if (su_ctx->from.uid != UID_ROOT)
if (su_ctx->notify)
app_send_result(su_ctx, DENY);
LOGW("su: request rejected (%u->%u)", su_ctx->from.uid, su_ctx->to.uid);
LOGW("su: request rejected (%u->%u)", su_ctx->info->uid, su_ctx->to.uid);
fprintf(stderr, "%s\n", strerror(EACCES));
exit(EXIT_FAILURE);
}
@ -147,7 +135,17 @@ static void socket_cleanup() {
static void cleanup_signal(int sig) {
socket_cleanup();
exit(EXIT_FAILURE);
exit2(EXIT_FAILURE);
}
__attribute__ ((noreturn)) void exit2(int status) {
// Handle the pipe, or the daemon will get stuck
if (su_ctx->info->policy == QUERY) {
xwrite(pipefd[1], &su_ctx->info->policy, sizeof(su_ctx->info->policy));
close(pipefd[0]);
close(pipefd[1]);
}
exit(status);
}
int su_daemon_main(int argc, char **argv) {
@ -199,35 +197,8 @@ int su_daemon_main(int argc, char **argv) {
}
}
// Default values
struct su_context ctx = {
.from = {
.pid = su_credentials.pid,
.uid = su_credentials.uid,
},
.to = {
.uid = UID_ROOT,
.login = 0,
.keepenv = 0,
.shell = DEFAULT_SHELL,
.command = NULL,
.argv = argv,
.argc = argc,
},
.user = {
.android_user_id = 0,
.multiuser_mode = get_multiuser_mode(),
.database_path = APP_DATA_PATH REQUESTOR_DATABASE_PATH,
.base_path = APP_DATA_PATH REQUESTOR
},
.umask = 022,
};
su_ctx = &ctx;
struct stat st;
int c, socket_serv_fd, fd;
char result[64];
policy_t dballow;
struct option long_opts[] = {
{ "command", required_argument, NULL, 'c' },
{ "help", no_argument, NULL, 'h' },
@ -242,30 +213,31 @@ int su_daemon_main(int argc, char **argv) {
while ((c = getopt_long(argc, argv, "c:hlmps:Vvuz:", long_opts, NULL)) != -1) {
switch (c) {
case 'c':
ctx.to.command = concat_commands(argc, argv);
su_ctx->to.command = concat_commands(argc, argv);
optind = argc;
su_ctx->notify = 1;
break;
case 'h':
usage(EXIT_SUCCESS);
break;
case 'l':
ctx.to.login = 1;
su_ctx->to.login = 1;
break;
case 'm':
case 'p':
ctx.to.keepenv = 1;
su_ctx->to.keepenv = 1;
break;
case 's':
ctx.to.shell = optarg;
su_ctx->to.shell = optarg;
break;
case 'V':
printf("%d\n", MAGISK_VER_CODE);
exit(EXIT_SUCCESS);
exit2(EXIT_SUCCESS);
case 'v':
printf("%s\n", MAGISKSU_VER_STR);
exit(EXIT_SUCCESS);
exit2(EXIT_SUCCESS);
case 'u':
switch (ctx.user.multiuser_mode) {
switch (su_ctx->user.multiuser_mode) {
case MULTIUSER_MODE_USER:
printf("Owner only: Only owner has root access\n");
break;
@ -276,7 +248,7 @@ int su_daemon_main(int argc, char **argv) {
printf("User independent: Each user has its own separate root rules\n");
break;
}
exit(EXIT_SUCCESS);
exit2(EXIT_SUCCESS);
case 'z':
// Do nothing, placed here for legacy support :)
break;
@ -286,8 +258,12 @@ int su_daemon_main(int argc, char **argv) {
usage(2);
}
}
su_ctx->to.argc = argc;
su_ctx->to.argv = argv;
if (optind < argc && !strcmp(argv[optind], "-")) {
ctx.to.login = 1;
su_ctx->to.login = 1;
optind++;
}
/* username or uid */
@ -299,14 +275,14 @@ int su_daemon_main(int argc, char **argv) {
/* It seems we shouldn't do this at all */
errno = 0;
ctx.to.uid = strtoul(argv[optind], &endptr, 10);
su_ctx->to.uid = strtoul(argv[optind], &endptr, 10);
if (errno || *endptr) {
LOGE("Unknown id: %s\n", argv[optind]);
fprintf(stderr, "Unknown id: %s\n", argv[optind]);
exit(EXIT_FAILURE);
}
} else {
ctx.to.uid = pw->pw_uid;
su_ctx->to.uid = pw->pw_uid;
}
optind++;
}
@ -314,54 +290,28 @@ int su_daemon_main(int argc, char **argv) {
optind++;
}
// The su_context setup is done, now every error leads to deny
// Setup done, now every error leads to deny
err_handler = deny;
// It's in multiuser mode
if (ctx.from.uid > 99999) {
ctx.user.android_user_id = ctx.from.uid / 100000;
ctx.from.uid %= 100000;
switch (ctx.user.multiuser_mode) {
case MULTIUSER_MODE_OWNER_ONLY:
deny();
case MULTIUSER_MODE_USER:
snprintf(ctx.user.database_path, PATH_MAX, "%s/%d/%s",
USER_DATA_PATH, ctx.user.android_user_id, REQUESTOR_DATABASE_PATH);
snprintf(ctx.user.base_path, PATH_MAX, "%s/%d/%s",
USER_DATA_PATH, ctx.user.android_user_id, REQUESTOR);
break;
}
}
// verify if Magisk Manager is installed
xstat(ctx.user.base_path, &st);
// always allow if this is Magisk Manager
if (ctx.from.uid == (st.st_uid % 100000)) {
allow();
}
// odd perms on superuser data dir
if (st.st_gid != st.st_uid) {
LOGE("Bad uid/gid %d/%d for Superuser Requestor application",
(int)st.st_uid, (int)st.st_gid);
deny();
}
// Check property of root configuration
char *root_prop = getprop(ROOT_ACCESS_PROP);
if (root_prop) {
int prop_status = atoi(root_prop);
switch (prop_status) {
case ROOT_ACCESS_DISABLED:
LOGE("Root access is disabled!\n");
exit(EXIT_FAILURE);
case ROOT_ACCESS_APPS_ONLY:
if (ctx.from.uid == UID_SHELL)
if (su_ctx->info->uid == UID_SHELL) {
LOGE("Root access is disabled for ADB!\n");
exit(EXIT_FAILURE);
}
break;
case ROOT_ACCESS_ADB_ONLY:
if (ctx.from.uid != UID_SHELL)
if (su_ctx->info->uid != UID_SHELL) {
LOGE("Root access limited to ADB only!\n");
exit(EXIT_FAILURE);
}
break;
case ROOT_ACCESS_APPS_AND_ADB:
default:
@ -373,40 +323,9 @@ int su_daemon_main(int argc, char **argv) {
setprop(ROOT_ACCESS_PROP, xstr(ROOT_ACCESS_APPS_AND_ADB));
}
// Allow root to start root
if (ctx.from.uid == UID_ROOT) {
allow();
}
mkdir(REQUESTOR_CACHE_PATH, 0770);
if (chown(REQUESTOR_CACHE_PATH, st.st_uid, st.st_gid)) {
PLOGE("chown (%s, %u, %u)", REQUESTOR_CACHE_PATH, st.st_uid, st.st_gid);
}
if (setgroups(0, NULL)) {
PLOGE("setgroups");
}
if (setegid(st.st_gid)) {
PLOGE("setegid (%u)", st.st_gid);
}
if (seteuid(st.st_uid)) {
PLOGE("seteuid (%u)", st.st_uid);
}
// If db exits, check directly instead query application
dballow = database_check(&ctx);
switch (dballow) {
case INTERACTIVE:
break;
case ALLOW:
allow();
case DENY:
default:
deny();
}
// New request or no db exist, notify app for response
socket_serv_fd = socket_create_temp(ctx.sock_path, sizeof(ctx.sock_path));
// New request or no db exist, notify user for response
if (su_ctx->info->policy == QUERY) {
socket_serv_fd = socket_create_temp(su_ctx->sock_path, sizeof(su_ctx->sock_path));
setup_sighandlers(cleanup_signal);
// Start activity
@ -415,20 +334,27 @@ int su_daemon_main(int argc, char **argv) {
atexit(socket_cleanup);
fd = socket_accept(socket_serv_fd);
socket_send_request(fd, &ctx);
socket_send_request(fd, su_ctx);
socket_receive_result(fd, result, sizeof(result));
close(fd);
close(socket_serv_fd);
socket_cleanup();
if (strcmp(result, "socket:DENY") == 0) {
deny();
} else if (strcmp(result, "socket:ALLOW") == 0) {
allow();
} else {
LOGE("unknown response from Superuser Requestor: %s", result);
deny();
if (strcmp(result, "socket:ALLOW") == 0)
su_ctx->info->policy = ALLOW;
else
su_ctx->info->policy = DENY;
// Report the policy to main daemon
xwrite(pipefd[1], &su_ctx->info->policy, sizeof(su_ctx->info->policy));
close(pipefd[0]);
close(pipefd[1]);
}
if (su_ctx->info->policy == ALLOW)
allow();
else
deny();
}

28
su.h
View File

@ -7,6 +7,8 @@
#include <limits.h>
#include <sys/types.h>
#include "list.h"
#define MAGISKSU_VER_STR xstr(MAGISK_VERSION) ":MAGISKSU (topjohnwu)"
// Property check for root access
@ -43,9 +45,20 @@
#define DEFAULT_SHELL "/system/bin/sh"
typedef enum {
QUERY = 0,
DENY = 1,
ALLOW = 2,
} policy_t;
struct su_initiator {
pid_t pid;
unsigned uid;
policy_t policy;
pthread_mutex_t lock;
int count;
int clock;
struct list_head pos;
};
struct su_request {
@ -76,24 +89,21 @@ struct su_user_info {
};
struct su_context {
struct su_initiator from;
struct su_initiator *info;
struct su_request to;
struct su_user_info user;
int notify;
mode_t umask;
char sock_path[PATH_MAX];
};
typedef enum {
INTERACTIVE = 0,
DENY = 1,
ALLOW = 2,
} policy_t;
extern struct ucred su_credentials;
extern struct su_context *su_ctx;
extern int pipefd[2];
// su.c
int su_daemon_main(int argc, char **argv);
__attribute__ ((noreturn)) void exit2(int status);
// su_client.c
@ -109,7 +119,7 @@ void app_send_request(struct su_context *ctx);
// db.c
policy_t database_check(struct su_context *ctx);
void database_check(struct su_context *ctx);
// misc.c

216
su_client.c → su_daemon.c
View File

@ -1,11 +1,12 @@
/* su_client.c - The entrypoint for su, connect to daemon and send correct info
*/
#define _GNU_SOURCE
#include <limits.h>
#include <unistd.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <signal.h>
@ -16,17 +17,24 @@
#include "magisk.h"
#include "daemon.h"
#include "resetprop.h"
#include "utils.h"
#include "su.h"
#include "pts.h"
#include "list.h"
// Constants for the atty bitfield
#define ATTY_IN 1
#define ATTY_OUT 2
#define ATTY_ERR 4
struct ucred su_credentials;
static __thread int client_fd;
#define TIMEOUT 3
static struct list_head active_list, waiting_list;
static pthread_t su_collector = 0;
static pthread_mutex_t list_lock = PTHREAD_MUTEX_INITIALIZER;
int pipefd[2];
static void sighandler(int sig) {
restore_stdin();
@ -53,27 +61,181 @@ static void sighandler(int sig) {
static void sigpipe_handler(int sig) {
LOGD("su: Client killed unexpectedly\n");
close(client_fd);
pthread_exit(NULL);
}
static int get_multiuser_mode() {
char *prop = getprop(MULTIUSER_MODE_PROP);
if (prop) {
int ret = atoi(prop);
free(prop);
return ret;
}
return MULTIUSER_MODE_OWNER_ONLY;
}
// Maintain the lists periodically
static void *collector(void *args) {
LOGD("su: collector started\n");
struct list_head *pos, *temp;
struct su_initiator *node;
while(1) {
sleep(1);
pthread_mutex_lock(&list_lock);
list_for_each(pos, &active_list) {
node = list_entry(pos, struct su_initiator, pos);
--node->clock;
// Timeout, move to waiting list
if (node->clock == 0) {
temp = pos;
pos = pos->prev;
list_pop(temp);
list_insert_end(&waiting_list, temp);
}
}
list_for_each(pos, &waiting_list) {
node = list_entry(pos, struct su_initiator, pos);
// Nothing is using the info, remove it
if (node->count == 0) {
temp = pos;
pos = pos->prev;
list_pop(temp);
pthread_mutex_destroy(&node->lock);
free(node);
}
}
pthread_mutex_unlock(&list_lock);
}
}
void su_daemon_receiver(int client) {
LOGD("su: get request from client: %d\n", client);
LOGD("su: request from client: %d\n", client);
struct su_initiator *info = NULL, *node;
struct list_head *pos;
int new_request = 0;
pthread_mutex_lock(&list_lock);
if (!su_collector) {
init_list_head(&active_list);
init_list_head(&waiting_list);
xpthread_create(&su_collector, NULL, collector, NULL);
}
// Get client credntial
struct ucred credential;
get_client_cred(client, &credential);
// Search for existing in the active list
list_for_each(pos, &active_list) {
node = list_entry(pos, struct su_initiator, pos);
if (node->uid == credential.uid)
info = node;
}
// If no exist, create a new request
if (info == NULL) {
new_request = 1;
info = malloc(sizeof(*info));
info->uid = credential.uid;
info->policy = QUERY;
info->count = 0;
pthread_mutex_init(&info->lock, NULL);
list_insert_end(&active_list, &info->pos);
}
info->clock = TIMEOUT; /* Reset timer */
++info->count; /* Increment reference count */
pthread_mutex_unlock(&list_lock);
LOGD("su: request from uid=[%d] (#%d)\n", info->uid, info->count);
// Lock before the policy is determined
pthread_mutex_lock(&info->lock);
info->pid = credential.pid;
// Default values
struct su_context ctx = {
.info = info,
.to = {
.uid = UID_ROOT,
.login = 0,
.keepenv = 0,
.shell = DEFAULT_SHELL,
.command = NULL,
},
.user = {
.android_user_id = info->uid / 100000,
.multiuser_mode = get_multiuser_mode(),
},
.umask = 022,
.notify = new_request,
};
su_ctx = &ctx;
snprintf(su_ctx->user.database_path, PATH_MAX, "%s/%d/%s",
USER_DATA_PATH, su_ctx->user.android_user_id, REQUESTOR_DATABASE_PATH);
snprintf(su_ctx->user.base_path, PATH_MAX, "%s/%d/%s",
USER_DATA_PATH, su_ctx->user.android_user_id, REQUESTOR);
// verify if Magisk Manager is installed
struct stat st;
xstat(su_ctx->user.base_path, &st);
// odd perms on superuser data dir
if (st.st_gid != st.st_uid) {
LOGE("Bad uid/gid %d/%d for Superuser Requestor application", st.st_uid, st.st_gid);
info->policy = DENY;
}
// Not cached, do the checks
if (info->policy == QUERY) {
if (su_ctx->user.android_user_id &&
su_ctx->user.multiuser_mode == MULTIUSER_MODE_OWNER_ONLY) {
info->policy = DENY;
su_ctx->notify = 0;
}
// always allow if this is Magisk Manager
if (info->policy == QUERY && (info->uid % 100000) == (st.st_uid % 100000)) {
info->policy = ALLOW;
su_ctx->notify = 0;
}
// always allow if it's root
if (info->uid == UID_ROOT) {
info->policy = ALLOW;
su_ctx->notify = 0;
}
// If not determined, check database
if (info->policy == QUERY)
database_check(su_ctx);
// If still not determined, open a pipe and wait for results
if (info->policy == QUERY)
pipe2(pipefd, O_CLOEXEC);
}
// Fork a new process, the child process will need to setsid,
// open a pseudo-terminal if needed, and will eventually run exec
// The parent process will wait for the result and
// send the return code back to our client
int child = fork();
if (child < 0) {
write(client, &child, sizeof(child));
close(client);
if (child < 0)
PLOGE("fork");
return;
} else if (child != 0) {
// For sighandler to close it
client_fd = client;
if (child) {
// Wait for results
if (info->policy == QUERY) {
xxread(pipefd[0], &info->policy, sizeof(info->policy));
close(pipefd[0]);
close(pipefd[1]);
}
// The policy is determined, unlock
pthread_mutex_unlock(&info->lock);
// Wait result
LOGD("su: wait_result waiting for %d\n", child);
@ -91,10 +253,13 @@ void su_daemon_receiver(int client) {
code = -1;
// Pass the return code back to the client
write_int(client, code);
write(client, &code, sizeof(code)); /* Might SIGPIPE, ignored */
LOGD("su: return code to client: %d\n", code);
close(client);
// Decrement reference count
--info->count;
return;
}
@ -106,14 +271,11 @@ void su_daemon_receiver(int client) {
// Become session leader
xsetsid();
// Get the credentials
get_client_cred(client, &su_credentials);
// Let's read some info from the socket
int argc = read_int(client);
if (argc < 0 || argc > 512) {
LOGE("unable to allocate args: %d", argc);
exit(1);
exit2(1);
}
LOGD("su: argc=[%d]\n", argc);
@ -149,9 +311,9 @@ void su_daemon_receiver(int client) {
xstat(pts_slave, &stbuf);
//If caller is not root, ensure the owner of pts_slave is the caller
if(stbuf.st_uid != su_credentials.uid && su_credentials.uid != 0) {
if(stbuf.st_uid != credential.uid && credential.uid != 0) {
LOGE("su: Wrong permission of pts_slave");
exit(1);
exit2(1);
}
// Opening the TTY has to occur after the
@ -182,6 +344,20 @@ void su_daemon_receiver(int client) {
close(ptsfd);
mkdir(REQUESTOR_CACHE_PATH, 0770);
if (chown(REQUESTOR_CACHE_PATH, st.st_uid, st.st_gid))
PLOGE("chown (%s, %u, %u)", REQUESTOR_CACHE_PATH, st.st_uid, st.st_gid);
if (setgroups(0, NULL))
PLOGE("setgroups");
if (setegid(st.st_gid))
PLOGE("setegid (%u)", st.st_gid);
if (seteuid(st.st_uid))
PLOGE("seteuid (%u)", st.st_uid);
su_daemon_main(argc, argv);
}

9
su_socket.c
View File

@ -12,6 +12,7 @@
#include <sys/socket.h>
#include <sys/un.h>
#include <selinux/selinux.h>
#include <syscall.h>
#include "magisk.h"
#include "utils.h"
@ -28,7 +29,7 @@ int socket_create_temp(char *path, size_t len) {
memset(&sun, 0, sizeof(sun));
sun.sun_family = AF_LOCAL;
snprintf(path, len, "%s/.socket%d", REQUESTOR_CACHE_PATH, getpid());
snprintf(path, len, "%s/.socket%d", REQUESTOR_CACHE_PATH, (int) syscall(SYS_gettid));
snprintf(sun.sun_path, sizeof(sun.sun_path), "%s", path);
/*
@ -52,8 +53,8 @@ int socket_accept(int serv_fd) {
fd_set fds;
int rc;
/* Wait 20 seconds for a connection, then give up. */
tv.tv_sec = 20;
/* Wait 60 seconds for a connection, then give up. */
tv.tv_sec = 60;
tv.tv_usec = 0;
FD_ZERO(&fds);
FD_SET(serv_fd, &fds);
@ -95,7 +96,7 @@ do { \
} while (0)
void socket_send_request(int fd, const struct su_context *ctx) {
write_token(fd, "uid", ctx->from.uid);
write_token(fd, "uid", ctx->info->uid);
write_token(fd, "eof", 1);
}