mlibc: getcwd implementation

2026-10-27 12:48:22 +00:00 · 2024-06-22 19:30:45 -03:00
parent b7505c9cf1
commit 017948a1aa
1 changed files with 133 additions and 3 deletions
@@ -207,10 +207,10 @@ index 0000000..e5b087a
 +
 diff --git mlibc-workdir/sysdeps/astral/generic/generic.cpp mlibc-workdir/sysdeps/astral/generic/generic.cpp
 new file mode 100644
-index 0000000..e11d5a4
+index 0000000..29795a8
 --- /dev/null
 +++ mlibc-workdir/sysdeps/astral/generic/generic.cpp
-@@ -0,0 +1,804 @@
+@@ -0,0 +1,934 @@
 +#include <bits/ensure.h>
 +#include <mlibc/debug.hpp>
 +#include <mlibc/all-sysdeps.hpp>
@@ -223,6 +223,9 @@ index 0000000..e11d5a4
 +#include <poll.h>
 +#include <sys/select.h>
 +#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dirent.h>
 +
 +static int gid;
 +static int egid;
@@ -327,6 +330,134 @@ index 0000000..e11d5a4
 +		return 0;
 +	}
 +
+	#ifndef MLIBC_BUILDING_RTLD
+
+	typedef struct {
+		ino_t d_ino;
+		off_t d_off;
+		unsigned short d_reclen;
+		unsigned char d_type;
+		char d_name[1024];
+	} dent_t;
+
+	// TODO at least cache the results and invalidade on a chdir
+	int sys_getcwd(char *buffer, size_t size) {
+		// cwd implemented in userspace
+		//
+		// note: not thread safe if the other threads chroot
+
+		char path[PATH_MAX];
+		int curroffset = PATH_MAX - 1;
+		path[curroffset] = '\0';
+
+
+		struct stat rootdir; // we will use dev and inode to find files and determine when the root dir has been hit
+		if (fstatat(-1, "/", &rootdir, 0))
+			return errno;
+
+		int dirfd = open(".", O_RDONLY);
+		if (dirfd < 0)
+			return errno;
+
+		struct stat dirstat;
+
+		if (fstat(dirfd, &dirstat)) {
+			close(dirfd);
+			return errno;
+		}
+
+		if (dirstat.st_dev == rootdir.st_dev && dirstat.st_ino == rootdir.st_ino) {
+			// cwd is root dir
+			close(dirfd);
+			if (size < 2)
+				return ERANGE;
+
+			buffer[0] = '/';
+			buffer[1] = '\0';
+			return 0;
+		}
+
+		struct stat upstat;
+		do {
+			if (fstat(dirfd, &dirstat)) {
+				close(dirfd);
+				return errno;
+			}
+
+			int upfd = openat(dirfd, "..", O_RDONLY);
+
+			if (fstat(upfd, &upstat)) {
+				close(upfd);
+				close(dirfd);
+				return errno;
+			}
+
+			close(dirfd);
+
+			dent_t dent;
+			size_t readcount;
+			while (sys_read_entries(upfd, &dent, sizeof(dent), &readcount) == 0) {
+				if (readcount == 0)
+					break;
+
+				if (strcmp(".", dent.d_name) == 0 || strcmp("..", dent.d_name) == 0)
+					continue;
+
+				int tmp = openat(upfd, dent.d_name, O_RDONLY);
+				// could have been deleted, continue
+				if (tmp < 0)
+					continue;
+
+				struct stat dentstat;
+				if (fstat(tmp, &dentstat)) {
+					close(tmp);
+					return errno;
+				}
+
+				close(tmp);
+
+				mlibc::infoLogger() << dent.d_name << frg::endlog;
+
+				if (dentstat.st_dev == dirstat.st_dev && dentstat.st_ino == dirstat.st_ino)
+					break;
+			}
+
+			// didn't find the directory
+			if (readcount == 0) {
+				close(upfd);
+				return ENOENT;
+			}
+
+			mlibc::infoLogger() << "got component: " << dent.d_name << frg::endlog;
+
+			dirfd = upfd;
+
+			// add it to the path to be returned
+			size_t namelen = strlen(dent.d_name);
+			curroffset -= namelen + 1; // + 1 as we add the leading '/' as well
+			// passed the start of the buffer
+			if (curroffset <= 1) {
+				close (dirfd);
+				return ENAMETOOLONG;
+			}
+
+			memcpy(&path[curroffset + 1], dent.d_name, namelen);
+			path[curroffset] = '/';
+		} while (upstat.st_dev != rootdir.st_dev || upstat.st_ino != rootdir.st_ino);
+
+		close(dirfd);
+
+		if (size < PATH_MAX - curroffset)
+			return ERANGE;
+
+		strcpy(buffer, &path[curroffset]);
+
+		mlibc::infoLogger() << "mlibc: sys_getcwd returning value " << buffer << frg::endlog;
+		return 0;
+	}
+
+	#endif
+
 +	int sys_pause() {
 +		long ret;
 +		return syscall(SYSCALL_PAUSE, &ret);
@@ -1014,7 +1145,6 @@ index 0000000..e11d5a4
 +	}
 +
 +} // namespace mlibc
-+
 diff --git mlibc-workdir/sysdeps/astral/include/astral/archctl.h mlibc-workdir/sysdeps/astral/include/astral/archctl.h
 new file mode 100644
 index 0000000..990eca0