/* See LICENSE file for copyright and license details. */
#include "libsbusd.h"
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#define STYPE_MAX(T) (long long int)((1ULL << (8 * sizeof(T) - 1)) - 1)
extern char *argv0;
void
libsbusd_weprintf(const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
fprintf(stderr, "%s: ", argv0);
vfprintf(stderr, fmt, args);
if (strchr(fmt, '\0')[-1] == ':') {
fputc(' ', stderr);
perror(NULL);
}
va_end(args);
}
int
libsbusd_doessubmatch(const char *sub, const char *key)
{
const char *sub_start = sub;
for (;;) {
while (*sub && *sub == *key) {
sub++;
key++;
}
if (!*key)
return !*sub;
if (!*sub)
return sub == sub_start || sub[-1] == '/';
if (*sub == '*') {
sub++;
while (*key && *key != '/')
key++;
continue;
}
return 0;
}
}
int
libsbusd_issubed(char *const *subs, size_t nsubs, const char *key)
{
while (nsubs--)
if (libsbusd_doessubmatch(subs[nsubs], key))
return 1;
return 0;
}
void
libsbusd_adduser(uid_t *users, size_t *nusers, const char *arg)
{
struct passwd *user;
long long int tmp;
if (!isdigit(*arg))
goto user_by_name;
errno = 0;
tmp = strtoll(arg, (void *)&arg, 10);
if (errno || *arg || tmp < 0 || tmp > STYPE_MAX(uid_t))
goto user_by_name;
users[(*nusers)++] = (uid_t)tmp;
return;
user_by_name:
user = getpwnam(arg);
if (!user)
eprintf("getpwnam %s:", arg);
users[(*nusers)++] = user->pw_uid;
}
static void
randomise(void *buf, size_t n)
{
char *p = buf;
while (n--)
*p++ = rand();
}
static void
print_address(struct sockaddr_un *addr)
{
char buf[2 * sizeof(addr->sun_path) + 1];
char *p = buf;
const unsigned char *a = (const unsigned char *)addr->sun_path;
size_t n = sizeof(addr->sun_path);
for (; n--; p += 2, a += 1) {
p[0] = "0123456789abcdef"[(int)*a >> 4];
p[1] = "0123456789abcdef"[(int)*a & 15];
}
*p = '\0';
printf("/dev/unix/abstract/%s\n", buf);
if (fflush(stdout) || ferror(stdout))
eprintf("failed print generated address:");
}
int
libsbusd_afunix(struct sockaddr_un *addr, int *fdp, const char *address)
{
const char *p, *q;
long int tmp;
int hi, lo;
size_t n;
char *a;
memset(addr, 0, sizeof(*addr));
addr->sun_family = AF_UNIX;
if (strstr(address, "/dev/fd/") == address) {
p = &address[sizeof("/dev/fd/") - 1];
if (!isdigit(*p))
goto def;
errno = 0;
tmp = strtol(p, &a, 10);
if (errno || *a || tmp < 0) {
errno = 0;
goto def;
}
if (tmp > INT_MAX) {
errno = EBADF;
return -1;
}
*fdp = (int)tmp;
return LIBSBUS_AFUNIX_FD;
} else if (!strcmp(address, "/dev/unix/abstract")) {
return LIBSBUS_AFUNIX_RANDOM;
} else if (strstr(address, "/dev/unix/abstract/") == address) {
p = &address[sizeof("/dev/unix/abstract/") - 1];
n = strlen(p);
if (n & 1)
goto def;
for (q = p; *q; q++)
if (!isxdigit(*q))
goto def;
if (n > sizeof(addr->sun_path) * 2) {
errno = ENAMETOOLONG;
return -1;
}
a = addr->sun_path;
for (; *p; p += 2) {
hi = (p[0] & 15) + 9 * !isdigit(p[0]);
lo = (p[1] & 15) + 9 * !isdigit(p[1]);
*a++ = (hi << 4) | lo;
}
return LIBSBUS_AFUNIX_ABSTRACT;
} else {
def:
if (strlen(address) >= sizeof(addr->sun_path)) {
errno = ENAMETOOLONG;
return -1;
}
strcpy(addr->sun_path, address);
return LIBSBUS_AFUNIX_CONCRETE;
}
}
int
libsbusd_mksocket(struct sockaddr_un *addr, const char *address, int reuse, mode_t mode)
{
int fd, randaddr = 0, listening = 0;
switch (libsbusd_afunix(addr, &fd, address)) {
case LIBSBUS_AFUNIX_FD:
reuse = 0;
break;
case LIBSBUS_AFUNIX_RANDOM:
randaddr = 1;
reuse = 0;
fd = -1;
break;
case LIBSBUS_AFUNIX_ABSTRACT:
reuse = 0;
fd = -1;
break;
case LIBSBUS_AFUNIX_CONCRETE:
fd = -1;
break;
default:
eprintf("bad unix socket address:");
exit(1);
}
if (reuse)
unlink(addr->sun_path);
if (fd < 0) {
fd = socket(PF_UNIX, SOCK_SEQPACKET, 0);
if (fd < 0)
eprintf("socket PF_UNIX SOCK_SEQPACKET:");
if (fchmod(fd, mode))
eprintf("fchmod <socket> %o:", mode);
if (randaddr) {
srand((unsigned)time(NULL));
for (;;) {
randomise(&addr->sun_path[1], sizeof(addr->sun_path) - 1);
if (!bind(fd, (void *)addr, sizeof(*addr)))
break;
else if (errno != EADDRINUSE)
eprintf("bind <random abstract address>:");
}
print_address(addr);
} else {
if (bind(fd, (void *)addr, sizeof(*addr))) {
if (*addr->sun_path)
eprintf("bind %s:", addr->sun_path);
else
eprintf("bind <abstract:%s>:", &address[sizeof("/dev/unix/abstract/") - 1]);
}
}
} else {
if (mode & 0070)
weprintf("ignoring -g due to using passed down socket\n");
if (mode & 0007)
weprintf("ignoring -o due to using passed down socket\n");
if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &listening, &(socklen_t){sizeof(listening)}))
eprintf("getsockopt SOL_SOCKET SO_ACCEPTCONN:");
}
if (!listening && listen(fd, SOMAXCONN))
eprintf("listen:");
return fd;
}
void
libsbusd_daemonise(const char *pidfile, void (*sigexit)(int))
{
pid_t pid;
int rw[2], status = 0, fd;
FILE *fp;
if (pipe(rw))
eprintf("pipe:");
switch ((pid = fork())) {
case -1:
eprintf("fork:");
case 0:
close(rw[0]);
setsid();
switch (fork()) {
case -1:
eprintf("fork:");
case 0:
if (signal(SIGHUP, SIG_IGN) == SIG_ERR)
weprintf("signal SIGHUP SIG_IGN:");
if (signal(SIGINT, sigexit) == SIG_ERR)
weprintf("signal SIGINT <exit>:");
if (pidfile) {
pid = getpid();
fd = open(pidfile, O_WRONLY | O_CREAT | O_EXCL, 0644);
if (fd < 0)
eprintf("open %s O_WRONLY O_CREAT O_EXCL:", pidfile);
fp = fdopen(fd, "w");
fprintf(fp, "%li\n", (long int)pid);
if (fflush(fp) || ferror(fp))
eprintf("fprintf %s:", pidfile);
fclose(fp);
}
if (chdir("/"))
eprintf("chdir /:");
close(STDIN_FILENO);
close(STDOUT_FILENO);
if (isatty(STDERR_FILENO)) {
fd = open("/dev/null", O_WRONLY);
if (fd)
eprintf("open /dev/null O_WRONLY:");
if (dup2(fd, STDERR_FILENO) != STDERR_FILENO)
eprintf("dup2 /dev/null /dev/stderr:");
close(fd);
}
if (write(rw[1], &status, 1) < 1)
eprintf("write <pipe>:");
close(rw[1]);
break;
default:
exit(0);
}
break;
default:
close(rw[1]);
if (waitpid(pid, &status, 0) != pid)
eprintf("waitpid:");
if (status)
exit(1);
switch (read(rw[0], &status, 1)) {
case -1:
eprintf("read <pipe>:");
case 0:
exit(1);
default:
exit(0);
}
}
}
void
libsbusd_initalise(int foreground, const char **pidfilep, void (*sigexit)(int))
{
if (foreground) {
close(STDIN_FILENO);
close(STDOUT_FILENO);
if (signal(SIGHUP, sigexit) == SIG_ERR)
weprintf("signal SIGHUP <exit>:");
if (signal(SIGINT, sigexit) == SIG_ERR)
weprintf("signal SIGINT <exit>:");
*pidfilep = NULL;
} else {
if (!strcmp(*pidfilep, "/dev/null"))
*pidfilep = NULL;
libsbusd_daemonise(*pidfilep, sigexit);
}
}
