Fix two errors and move reuseable code from sbusd to libsbusd

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 342 insertions, 0 deletions

diff --git a/libsbusd.c b/libsbusd.c
new file mode 100644
index 0000000..7c0596e
--- /dev/null
+++ b/libsbusd.c
@@ -0,0 +1,342 @@
+/* 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);
+	}
+}