Added chdir(2), getcwd(2), which mxsh and ls now uses.

libmaxsi/c/hsrc/unistd.h

@@ -78,7 +78,6 @@ __BEGIN_DECLS
 #ifndef SORTIX_UNIMPLEMENTED
 int access(const char*, int);
 unsigned alarm(unsigned);
-int chdir(const char*);
 int chown(const char*, uid_t, gid_t);
 size_t confstr(int, char*, size_t);
 char* crypt(const char*, const char*);
@@ -100,7 +99,6 @@ int fexecve(int, char* const [], char* const []);
 long fpathconf(int, int);
 int fsync(int);
 int ftruncate(int, off_t);
-char* getcwd(char*, size_t);
 gid_t getegid(void);
 uid_t geteuid(void);
 gid_t getgid(void);
@@ -157,10 +155,12 @@ extern char* optarg;
 extern int opterr, optind, optopt;
 #endif
 
+int chdir(const char*);
 int close(int);
 int dup(int);
 void _exit(int);
 pid_t fork(void);
+char* getcwd(char*, size_t);
 pid_t getpid(void);
 pid_t getppid(void);
 int pipe(int [2]);

libmaxsi/hsrc/error.h

@@ -55,6 +55,8 @@ namespace Maxsi
 		const int EROFS = 20;
 		const int EINVAL = 21;
 		const int ENOTDIR = 22;
+		const int ENOMEM = 23;
+		const int ERANGE = 24;
 
 		extern int _errornumber;
 

libmaxsi/io.cpp

@@ -38,6 +38,8 @@ namespace Maxsi
 	DEFN_SYSCALL1(int, SysDup, 22, int);
 	DEFN_SYSCALL3(int, SysOpen, 23, const char*, int, mode_t);
 	DEFN_SYSCALL3(int, SysReadDirEnts, 24, int, struct sortix_dirent*, size_t);
+	DEFN_SYSCALL1(int, SysChDir, 25, const char*);
+	DEFN_SYSCALL2(char*, SysGetCWD, 26, char*, size_t);
 
 	size_t Print(const char* Message)
 	{
@@ -102,6 +104,16 @@ namespace Maxsi
 	{
 		return SysReadDirEnts(fd, dirent, size);
 	}
+
+	extern "C" int chdir(const char* path)
+	{
+		return SysChDir(path);
+	}
+
+	extern "C" char* getcwd(char* buf, size_t size)
+	{
+		return SysGetCWD(buf, size);
+	}
 #endif
 
 }

sortix/directory.cpp

@@ -30,6 +30,8 @@
 #include "process.h"
 #include "device.h"
 #include "directory.h"
+#include "filesystem.h"
+#include "mount.h"
 
 using namespace Maxsi;
 
@@ -84,9 +86,127 @@ namespace Sortix
 			}
 		}
 
+		int SysChDir(const char* path)
+		{
+			// Calculate the absolute new path.
+			Process* process = CurrentProcess();
+			const char* wd = process->workingdir;
+			char* abs = MakeAbsolute(wd, path);
+			if ( !abs ) { Error::Set(Error::ENOMEM); return -1; }
+			size_t abslen = String::Length(abs);
+			if ( 1 < abslen && abs[abslen-1] == '/' )
+			{
+				abs[abslen-1] = '\0';
+			}
+
+			// Lookup the path and see if it is a directory.
+			size_t pathoffset = 0;
+			DevFileSystem* fs = Mount::WhichFileSystem(abs, &pathoffset);
+			if ( !fs ) { delete[] abs; Error::Set(Error::EINVAL); return -1; }
+			Device* dev = fs->Open(abs + pathoffset, O_SEARCH | O_DIRECTORY, 0);
+			if ( !dev ) { Error::Set(Error::ENOTDIR); return -1; }
+			dev->Unref();
+
+			// Alright, the path passed.
+			delete[] process->workingdir; // Works if it was NULL.
+			process->workingdir = abs;
+
+			return 0;
+		}
+
+		char* SysGetCWD(char* buf, size_t size)
+		{
+			// Calculate the absolute new path.
+			Process* process = CurrentProcess();
+			const char* wd = process->workingdir;
+			if ( !wd ) { wd = "/"; }
+			size_t wdsize = String::Length(wd) + 1;
+			if ( size < wdsize ) { Error::Set(Error::ERANGE); return NULL; }
+			String::Copy(buf, wd);
+			return buf;
+		}
+
 		void Init()
 		{
 			Syscall::Register(SYSCALL_READDIRENTS, (void*) SysReadDirEnts);
+			Syscall::Register(SYSCALL_CHDIR, (void*) SysChDir);
+			Syscall::Register(SYSCALL_GETCWD, (void*) SysGetCWD);
+		}
+
+		// Allocate a byte too much, in case you want to add a trailing slash.
+		char* MakeAbsolute(const char* wd, const char* rel)
+		{
+			// If given no wd, then interpret from the root.
+			if ( !wd ) { wd = "/"; }
+
+			// The resulting size won't ever be larger than this.
+			size_t wdlen = String::Length(wd);
+			size_t resultsize = wdlen + String::Length(rel) + 2;
+			char* result = new char[resultsize + 1];
+			if ( !result ) { return NULL; }
+
+			// Detect if rel is relative to / or to wd, and then continue the
+			// interpretation from that point.
+			size_t offset;
+			if ( *rel == '/' ) { result[0] = '/'; offset = 1; rel++; }
+			else { String::Copy(result, wd); offset = wdlen; }
+
+			// Make sure the working directory ends with a slash.
+			if ( result[offset-1] != '/' ) { result[offset++] = '/'; }
+
+			bool leadingdots = true;
+			size_t dots = 0;
+			int c = 1;
+			while ( c ) // Exit after handling \0
+			{
+				c = *rel++;
+
+				// Don't insert double //'s into the final path.
+				if ( c == '/' && result[offset-1] == '/' ) { continue; }
+
+				// / or \0 means that we should interpret . and ..
+				if ( c == '/' || c == '\0' )
+				{
+					// If ., just remove the dot and ignore the slash.
+					if ( leadingdots && dots == 1 )
+					{
+						result[--offset] = '\0';
+						dots = 0;
+						continue;
+					}
+
+					// If .., remove .. and one element of the path.
+					if ( leadingdots && dots == 2 )
+					{
+						offset -= 2; // Remove ..
+						offset -= 1; // Remove the trailing slash
+						while ( offset )
+						{
+							if ( result[--offset] == '/' ) { break; }
+						}
+						result[offset++] = '/'; // Need to re-insert a slash.
+						result[offset] = '\0';
+						dots = 0;
+						continue;
+					}
+
+					// Reset the dot count after a slash.
+					dots = 0;
+				}
+
+				// The newest path element consisted solely of dots.
+				leadingdots = ( c == '/' || c == '.' );
+
+				// Count the number of leading dots in the path element.
+				if ( c == '.' && leadingdots ) { dots++; }
+
+				// Insert the character into the result.
+				result[offset++] = c;
+			}
+
+			// TODO: To avoid wasting space, should we String::Clone(result)?
+
+			return result;
 		}
 	}
 }

sortix/directory.h

@@ -57,6 +57,7 @@ namespace Sortix
 	namespace Directory
 	{
 		void Init();
+		char* MakeAbsolute(const char* wd, const char* rel);
 	}
 }
 

sortix/filesystem.cpp

@@ -23,11 +23,13 @@
 ******************************************************************************/
 
 #include "platform.h"
+#include <libmaxsi/error.h>
 #include <libmaxsi/memory.h>
 #include <libmaxsi/string.h>
 #include "syscall.h"
 #include "process.h"
 #include "filesystem.h"
+#include "directory.h"
 #include "mount.h"
 
 using namespace Maxsi;
@@ -38,22 +40,16 @@ namespace Sortix
 	{
 		Device* Open(const char* path, int flags, mode_t mode)
 		{
-			const char* workingdir = "/";
-			char* fullpath = NULL;
-			if ( *path != '/' )
-			{
-				size_t len = String::Length(workingdir) + String::Length(path);
-				fullpath = new char[len+1];
-				if ( !fullpath ) { return NULL; }
-				String::Copy(fullpath, workingdir);
-				String::Cat(fullpath, path);
-				path = fullpath;
-			}
+			Process* process = CurrentProcess();
+			const char* wd = process->workingdir;
+			char* abs = Directory::MakeAbsolute(wd, path);
+			if ( !abs ) { Error::Set(Error::ENOMEM); return NULL; }
+
 			size_t pathoffset = 0;
-			DevFileSystem* fs = Mount::WhichFileSystem(path, &pathoffset);
-			if ( !fs ) { delete[] fullpath; return NULL; }
-			Device* result = fs->Open(path + pathoffset, flags, mode);
-			delete[] fullpath;
+			DevFileSystem* fs = Mount::WhichFileSystem(abs, &pathoffset);
+			if ( !fs ) { delete[] abs; return NULL; }
+			Device* result = fs->Open(abs + pathoffset, flags, mode);
+			delete[] abs;
 			return result;
 		}
 

sortix/process.cpp

@@ -96,6 +96,7 @@ namespace Sortix
 		firstchild = NULL;
 		zombiechild = NULL;
 		firstthread = NULL;
+		workingdir = NULL;
 		mmapfrom = 0x80000000UL;
 		exitstatus = -1;
 		pid = AllocatePID();
@@ -110,6 +111,8 @@ namespace Sortix
 
 		// Avoid memory leaks.
 		ASSERT(segments == NULL);
+	
+		delete[] workingdir;
 
 		// TODO: Delete address space!
 	}
@@ -193,6 +196,8 @@ namespace Sortix
 
 		// Copy variables.
 		clone->mmapfrom = mmapfrom;
+		if ( workingdir ) { clone->workingdir = String::Clone(workingdir); }
+		else { clone->workingdir = NULL; }
 
 		// Now that the cloned process is fully created, we need to signal to
 		// its threads that they should insert themselves into the scheduler.

sortix/process.h

@@ -67,8 +67,7 @@ namespace Sortix
 	public:
 		addr_t addrspace;
 		int exitstatus;
-
-	public:
+		char* workingdir;
 		pid_t pid;
 
 	public:

sortix/syscallnum.h

@@ -50,7 +50,9 @@
 #define SYSCALL_DUP 22
 #define SYSCALL_OPEN 23
 #define SYSCALL_READDIRENTS 24
-#define SYSCALL_MAX_NUM 25 /* index of highest constant + 1 */
+#define SYSCALL_CHDIR 25
+#define SYSCALL_GETCWD 26
+#define SYSCALL_MAX_NUM 27 /* index of highest constant + 1 */
 
 #endif
 

utils/ls.cpp

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <fcntl.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/readdirents.h>
 #include <libmaxsi/platform.h>
 #include <libmaxsi/process.h>
@@ -37,7 +38,11 @@ int ls(const char* path)
 
 int main(int argc, char* argv[])
 {
-	const char* path = "/";
+	const size_t CWD_SIZE = 512;
+	char cwd[CWD_SIZE];
+	const char* path = getcwd(cwd, CWD_SIZE);
+	if ( !path ) { path = "."; }
+
 	if ( 1 < argc ) { path = argv[1]; }
 
 	return ls(path);

utils/mxsh.cpp

@@ -14,7 +14,12 @@ int status = 0;
 
 void command()
 {
-	printf("root@sortix / # ");	
+	const size_t CWD_SIZE = 512;
+	char cwd[CWD_SIZE];
+	const char* wd = getcwd(cwd, CWD_SIZE);
+	if ( !wd ) { wd = "?"; }
+
+	printf("root@sortix %s # ", wd);	
 
 	const size_t commandsize = 128;
 	char command[commandsize + 1];
@@ -81,6 +86,19 @@ void command()
 		exit(atoi(status));
 	}
 
+	if ( strcmp(argv[0], "cd") == 0 )
+	{
+		status = 0;
+		const char* newdir = "/";
+		if ( 1 < argc ) { newdir = argv[1]; }
+		if ( chdir(newdir) )
+		{
+			printf("cd: %s: cannot change directory\n", newdir);
+			status = 1;
+		}
+		return;
+	}
+
 	pid_t child = fork();
 	if ( child < 0 ) { printf("fork failed\n"); return; }
 	if ( child != 0 )