user: implement mlibc as the libc, finally.

It's finally done.. Signed-off-by: kaguya <vpshinomiya@protonmail.com>
2026-05-02 03:31:49 -04:00
parent 2fa39ad85a
commit 9a9b91c940
2387 changed files with 152741 additions and 315 deletions
@@ -0,0 +1,172 @@
+#include <bits/ensure.h>
+#include <errno.h>
+#include <frg/mutex.hpp>
+#include <frg/spinlock.hpp>
+#include <mlibc/debug.hpp>
+#include <paths.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <utmpx.h>
+
+#include <mlibc/posix-sysdeps.hpp>
+#include <mlibc/utmp.hpp>
+
+namespace {
+
+constexpr const char *defaultUtmpxPath = UTMPX_FILE;
+
+const char *utmpxPath = defaultUtmpxPath;
+frg::ticket_spinlock utmpxMutex;
+
+frg::optional<int> utmpxFd = frg::null_opt;
+
+utmpx returned;
+
+} // namespace
+
+void updwtmpx(const char *file, const struct utmpx *ut) {
+	int fd;
+	int err = mlibc::sys_open(file, O_RDWR | O_CREAT | O_CLOEXEC | O_APPEND, 0644, &fd);
+	if(err) {
+		mlibc::infoLogger() << "\e[31mmlibc: updwtmpx() failed to open " << file << ": "
+							<< strerror(err) << "\e[39m" << frg::endlog;
+		return;
+	}
+
+	mlibc::putUtmpEntry(fd, ut);
+
+	mlibc::sys_close(fd);
+}
+
+void endutxent(void) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(utmpxFd) {
+		mlibc::sys_close(utmpxFd.value());
+		utmpxFd = frg::null_opt;
+	}
+}
+
+void setutxent(void) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(!utmpxFd) {
+		int fd;
+
+		// If we are opening the utmp file as a non-root user with a root-made
+		// utmp, we need to open as a reader instead of a writer, O_RDWR will
+		// fail as no write permission can be obtained with 0644.
+		//
+		// The operations that need writing like updates will naturally fail
+		// because of the underlying sysdep failing.
+		int err = mlibc::sys_open(utmpxPath, O_RDWR | O_CREAT | O_CLOEXEC, 0644, &fd);
+		if(err == EACCES) {
+			err = mlibc::sys_open(utmpxPath, O_RDONLY | O_CLOEXEC, 0644, &fd);
+		}
+
+		if(err) {
+			mlibc::infoLogger() << "\e[31mmlibc: setutxent() failed to open " << utmpxPath << ": "
+			                    << strerror(err) << "\e[39m" << frg::endlog;
+			utmpxFd = frg::null_opt;
+		} else {
+			utmpxFd = fd;
+		}
+	} else {
+		off_t discard;
+		mlibc::sys_seek(utmpxFd.value(), 0, SEEK_SET, &discard);
+	}
+}
+
+struct utmpx *getutxent(void) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(!utmpxFd)
+		setutxent();
+	if(!utmpxFd) {
+		errno = ENOENT;
+		return nullptr;
+	}
+
+	if(int e = mlibc::getUtmpEntry(*utmpxFd, &returned); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return &returned;
+}
+
+struct utmpx *pututxline(const struct utmpx *ut) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(!utmpxFd)
+		setutxent();
+	if(!utmpxFd) {
+		errno = ENOENT;
+		return nullptr;
+	}
+
+	if(int e = mlibc::putUtmpEntry(*utmpxFd, ut); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return (utmpx *) ut;
+}
+
+int utmpxname(const char *file) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(strcmp(file, utmpxPath)) {
+		if(!strcmp(file, defaultUtmpxPath)) {
+			free((void *) utmpxPath);
+			utmpxPath = defaultUtmpxPath;
+		} else {
+			char *name = strdup(file);
+			if(!name)
+				return -1;
+
+			if(utmpxPath != defaultUtmpxPath)
+				free((void *) utmpxPath);
+
+			utmpxPath = name;
+		}
+	}
+
+	return 0;
+}
+
+struct utmpx *getutxid(const struct utmpx *ut) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(!utmpxFd)
+		setutxent();
+	if(!utmpxFd) {
+		errno = ENOENT;
+		return nullptr;
+	}
+
+	if(int e = mlibc::getUtmpEntryById(*utmpxFd, ut, &returned); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return &returned;
+}
+
+struct utmpx *getutxline(const struct utmpx *ut) {
+	frg::unique_lock lock{utmpxMutex};
+
+	if(!utmpxFd)
+		setutxent();
+	if(!utmpxFd) {
+		errno = ENOENT;
+		return nullptr;
+	}
+
+	if(int e = mlibc::getUtmpEntryByType(*utmpxFd, ut, &returned); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return &returned;
+}