lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 217 insertions, 0 deletions

diff --git a/lib/mlibc/options/glibc/generic/shadow-stubs.cpp b/lib/mlibc/options/glibc/generic/shadow-stubs.cpp
new file mode 100644
index 0000000..9ce6584
--- /dev/null
+++ b/lib/mlibc/options/glibc/generic/shadow-stubs.cpp
@@ -0,0 +1,217 @@
+#include <shadow.h>
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include <bits/ensure.h>
+#include <mlibc/debug.hpp>
+
+/*
+ * The code in this file is largely based on or taken from musl.
+ * This includes:
+ * - xatol
+ * - __parsespent
+ * - cleanup
+ * - getspnam_r
+ * - getspnam
+ */
+#define NUM(n) ((n) == -1 ? 0 : -1), ((n) == -1 ? 0 : (n))
+
+int putspent(const struct spwd *sp, FILE *f) {
+	auto str = [] (char *s) {
+		return ((s) ? (s) : "");
+	};
+	return fprintf(f, "%s:%s:%.*d:%.*d:%.*d:%.*d:%.*d:%.*d:%.*u\n",
+		str(sp->sp_namp), str(sp->sp_pwdp), NUM(sp->sp_lstchg),
+		NUM(sp->sp_min), NUM(sp->sp_max), NUM(sp->sp_warn),
+		NUM(sp->sp_inact), NUM(sp->sp_expire), NUM((int)sp->sp_flag)) < 0 ? -1 : 0;
+}
+#undef NUM
+
+static long xatol(char **s) {
+	long x;
+	if(**s == ':' || **s == '\n') {
+		return -1;
+	}
+	for(x = 0; (unsigned int)**s - '0' < 10U; ++*s) {
+		x = 10 * x + (**s - '0');
+	}
+	return x;
+}
+
+static int __parsespent(char *s, struct spwd *sp) {
+	sp->sp_namp = s;
+	if(!(s = strchr(s, ':'))) {
+		return -1;
+	}
+	*s = 0;
+
+	sp->sp_pwdp = ++s;
+	if(!(s = strchr(s, ':'))) {
+		return -1;
+	}
+	*s = 0;
+
+	s++;
+	sp->sp_lstchg = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_min = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_max = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_warn = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_inact = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_expire = xatol(&s);
+	if(*s != ':') {
+		return -1;
+	}
+
+	s++;
+	sp->sp_flag = xatol(&s);
+	if(*s != '\n') {
+		return -1;
+	}
+	return 0;
+}
+
+static void cleanup(void *p) {
+	fclose((FILE *)p);
+}
+
+int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct spwd **res) {
+	char path[20 + NAME_MAX];
+	FILE *f = 0;
+	int rv = 0;
+	int fd;
+	size_t k, l = strlen(name);
+	int skip = 0;
+	int cs;
+	int orig_errno = errno;
+
+	*res = 0;
+
+	/* Disallow potentially-malicious user names */
+	if(*name=='.' || strchr(name, '/') || !l) {
+		return errno = EINVAL;
+	}
+
+	/* Buffer size must at least be able to hold name, plus some.. */
+	if(size < l + 100) {
+		return errno = ERANGE;
+	}
+
+	/* Protect against truncation */
+	if(snprintf(path, sizeof path, "/etc/tcb/%s/shadow", name) >= (int)sizeof path) {
+		return errno = EINVAL;
+	}
+
+	fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC);
+	if(fd >= 0) {
+		struct stat st = {};
+		errno = EINVAL;
+		if(fstat(fd, &st) || !S_ISREG(st.st_mode) || !(f = fdopen(fd, "rb"))) {
+			pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+			close(fd);
+			pthread_setcancelstate(cs, 0);
+			return errno;
+		}
+	} else {
+		if(errno != ENOENT && errno != ENOTDIR) {
+			return errno;
+		}
+		f = fopen("/etc/shadow", "rbe");
+		if(!f) {
+			if(errno != ENOENT && errno != ENOTDIR) {
+				return errno;
+			}
+			return 0;
+		}
+	}
+
+	pthread_cleanup_push(cleanup, f);
+	while(fgets(buf, size, f) && (k = strlen(buf)) > 0) {
+		if(skip || strncmp(name, buf, l) || buf[l] != ':') {
+			skip = buf[k - 1] != '\n';
+			continue;
+		}
+		if(buf[k - 1] != '\n') {
+			rv = ERANGE;
+			break;
+		}
+
+		if(__parsespent(buf, sp) < 0) {
+			continue;
+		}
+		*res = sp;
+		break;
+	}
+	pthread_cleanup_pop(1);
+	errno = rv ? rv : orig_errno;
+	return rv;
+}
+
+int lckpwdf(void) {
+	mlibc::infoLogger() << "mlibc: lckpwdf is unimplemented like musl" << frg::endlog;
+	return 0;
+}
+
+int ulckpwdf(void) {
+	mlibc::infoLogger() << "mlibc: ulckpwdf is unimplemented like musl" << frg::endlog;
+	return 0;
+}
+
+// Musl defines LINE_LIM to 256
+#define LINE_LIM 256
+
+struct spwd *getspnam(const char *name) {
+	static struct spwd sp;
+	static char *line;
+	struct spwd *res;
+	int e;
+	int orig_errno = errno;
+
+	if(!line) {
+		line = (char *)malloc(LINE_LIM);
+	}
+	if(!line) {
+		return 0;
+	}
+	e = getspnam_r(name, &sp, line, LINE_LIM, &res);
+	errno = e ? e : orig_errno;
+	return res;
+}
+
+struct spwd *fgetspent(FILE *) {
+	__ensure(!"Not implemented");
+	__builtin_unreachable();
+}
+
+void endspent(void) {
+	mlibc::infoLogger() << "mlibc: endspent is a stub" << frg::endlog;
+}