16 files changed, 602 insertions, 63 deletions

diff --git a/src/user/lib/libc/Makefile b/src/user/lib/libc/Makefile
index 14a5421..d706635 100644
--- a/src/user/lib/libc/Makefile
+++ b/src/user/lib/libc/Makefile
@@ -1,6 +1,7 @@
 Out = _libc.o
 Obj = tce/syscall.o std/_dlmalloc.o \
-	  std/stdio.o std/stdlib.o std/string.o std/sched.o std/readline.o \
+	  std/stdio.o std/stdlib.o std/string.o std/ctype.o std/setjmp.o \
+	  std/sched.o std/readline.o \
 	  start.o
 
 include $(SrcPath)/common.make
diff --git a/src/user/lib/libc/include/ctype.h b/src/user/lib/libc/include/ctype.h
new file mode 100644
index 0000000..10a64df
--- /dev/null
+++ b/src/user/lib/libc/include/ctype.h
@@ -0,0 +1,24 @@
+#ifndef DEF_LIBC_CTYPE_H
+#define DEF_LIBC_CTYPE_H
+
+#include <types.h>
+
+#ifdef __cplusplus
+extern "C" { namespace libc {
+#endif
+
+
+int isalpha(int c);
+int isdigit(int c);
+int isalnum(int c);
+
+int tolower(int c);
+int toupper(int c);
+
+
+#ifdef __cplusplus
+} }
+#endif
+
+#endif
+
diff --git a/src/user/lib/libc/include/readline.h b/src/user/lib/libc/include/readline.h
index 1ec5baa..9fa2ee7 100644
--- a/src/user/lib/libc/include/readline.h
+++ b/src/user/lib/libc/include/readline.h
@@ -14,8 +14,8 @@ typedef struct _rdln_hist {
 extern "C" { namespace libc {
 #endif
 char *readln();
-char* freadln(FILE f);		// minimal line-reading function. user must free the returned value.
-char* freadline(FILE f, readline_history *h);
+char* freadln(FILE *f);		// minimal line-reading function. user must free the returned value.
+char* freadline(FILE *f, readline_history *h);
 #ifdef __cplusplus
 } }
 #endif
diff --git a/src/user/lib/libc/include/setjmp.h b/src/user/lib/libc/include/setjmp.h
new file mode 100644
index 0000000..3bf2027
--- /dev/null
+++ b/src/user/lib/libc/include/setjmp.h
@@ -0,0 +1,25 @@
+#ifndef DEF_LIBC_SETJMP_H
+#define DEF_LIBC_SETJMP_H
+
+#include <types.h>
+
+typedef struct {
+	uint32_t ebp;	//0
+	uint32_t ebx;	//4
+	uint32_t edi;	//8
+	uint32_t esi;	//12
+	uint32_t esp;	//16
+	uint32_t eip;	//20
+} jmp_buf[1];
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+int setjmp(jmp_buf env);
+void longjmp(jmp_buf, int val);
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
diff --git a/src/user/lib/libc/include/stdio.h b/src/user/lib/libc/include/stdio.h
index 72d355a..8fbefcd 100644
--- a/src/user/lib/libc/include/stdio.h
+++ b/src/user/lib/libc/include/stdio.h
@@ -8,14 +8,57 @@
 extern "C" { namespace libc {
 #endif
 
+#define EOF 0x1E0F
+
+#define TERM_INPUT_BUFFER_SIZE 256
+
+typedef struct {
+	int fd;
+	long pos;	// -1 : it's a stream
+	file_info info;
+	// terminal input buffer
+	// Possible states :
+	//	- tib_u_begin = tib_u_end = tib_begin : buffer is empty
+	//  - tib_begin = tib_u_begin < tib_u_end : buffer contains some data
+	//  - tib_begin < tib_u_begin < tib_u_end : buffer contains some data that is
+	//				being read, and some space for putting back characters
+	char *tib_begin, *tib_end, *tib_u_begin, *tib_u_end;
+	int term_echo;		// enable echoing of entered keypresses ?
+
+} FILE;
+
 extern FILE term;
+#define stdin (&term)
+#define stdout (&term)
+
+
+#define SEEK_SET 0x5EEC0001
+#define SEEK_CUR 0x5EEC0002
+#define SEEK_END 0x5EEC0003
+FILE *fopen(const char *path, const char *mode);
+void __tce_libc_fsetup(FILE *f); // INTERNAL
+
+// These two handle buffering for terminals
+int fgetc(FILE*);
+int ungetc(int, FILE*);
+
+// These do not handle buffering for terminals
+size_t fread(void* ptr, size_t size, size_t nmemb, FILE*);
+size_t fwrite(void* ptr, size_t size, size_t nmemb, FILE*);
+size_t fseek(FILE *stream, long offset, int whence);
+long ftell(FILE *stream);
+void fclose(FILE *f);
+
+int getchar();
+int scanf(const char *s, ...);	
+
+int print(const char *s);
+int printf(const char *s, ...);
 
-void print(const char *s);
-void printf(const char *s, ...);
 
-void fprint(FILE f, const char *s);
-void fprintf(FILE f, const char *s, ...);
-void vfprintf(FILE f, const char *s, va_list arg);
+int fprint(FILE *f, const char *s);
+int fprintf(FILE *f, const char *s, ...);
+int vfprintf(FILE *f, const char *s, va_list arg);
 
 #ifdef __cplusplus
 } }
diff --git a/src/user/lib/libc/include/stdlib.h b/src/user/lib/libc/include/stdlib.h
index 1cc5d16..e1b3326 100644
--- a/src/user/lib/libc/include/stdlib.h
+++ b/src/user/lib/libc/include/stdlib.h
@@ -1,5 +1,5 @@
-#ifndef DEF_STDLIB_H
-#define DEF_STDLIB_H
+#ifndef DEF_LIBC_STDLIB_H
+#define DEF_LIBC_STDLIB_H
 
 #include <types.h>
 #include <tce/syscall.h>
@@ -8,8 +8,19 @@
 extern "C" { namespace libc {
 #endif
 
+int atoi(char*);
+double atof(char*);
+
+#define RAND_MAX 32767
+int rand();
+void srand(unsigned int);
+
+void exit(int);
 void abort();
 extern volatile int errno;
+
+
+
 #ifdef __cplusplus
 } }
 #endif
diff --git a/src/user/lib/libc/include/string.h b/src/user/lib/libc/include/string.h
index 5b86868..2f4f4ca 100644
--- a/src/user/lib/libc/include/string.h
+++ b/src/user/lib/libc/include/string.h
@@ -18,6 +18,7 @@ char *strdup(const char *src);
 char *strchr(const char *str, int c);
 char *strcat(char *dest, const char *src);
 int strcmp(const char *s1, const char *s2);
+char *strncpy(char *dest, const char *src, int max);
 
 char* format_int(char* buf, int number);
 char* format_hex(char *buf, unsigned v);
@@ -25,6 +26,10 @@ int printf_str_len(const char *fmt, va_list arg);
 int vsprintf(char *buf, const char *fmt, va_list arg);
 int sprintf(char *buf, const char *fmt, ...);
 
+
+void simplify_path(char *p);		// simplifies /../, // and /./
+char *path_cat(const char *a, const char *b, int trailing_slash);	// allocates a new buffer
+
 #ifdef __cplusplus
 } }
 #endif
diff --git a/src/user/lib/libc/include/tce/syscall.h b/src/user/lib/libc/include/tce/syscall.h
index 6679f1a..4a1c6ef 100644
--- a/src/user/lib/libc/include/tce/syscall.h
+++ b/src/user/lib/libc/include/tce/syscall.h
@@ -23,17 +23,17 @@ int proc_priv();
 void* sbrk(ptrdiff_t size);
 void brk(void* ptr);
 
-int run(const char* file, const char** args, FILE zero_fd);
+int run(const char* file, const char** args, int zero_fd);
 int waitpid(int pid, int block);
 
-FILE open(const char* filename, int mode);
-FILE open_relative(FILE root, const char* filename, int mode);
+int open(const char* filename, int mode);
+int open_relative(int root, const char* filename, int mode);
 int stat(const char* filename, file_info *info);
-int stat_relative(FILE root, const char* filename, file_info *info);
-int statf(FILE file, file_info *info);
-void close(FILE file);
-int read(FILE file, size_t offset, size_t len, char *buffer);
-int write(FILE file, size_t offset, size_t len, const char *buffer);
+int stat_relative(int root, const char* filename, file_info *info);
+int statf(int file, file_info *info);
+void close(int file);
+int read(int file, size_t offset, size_t len, char *buffer);
+int write(int file, size_t offset, size_t len, const char *buffer);
 int link(const char* from, const char* to, int mode);
 
 #ifdef __cplusplus
diff --git a/src/user/lib/libc/start.c b/src/user/lib/libc/start.c
index f15f90d..3f51fdb 100644
--- a/src/user/lib/libc/start.c
+++ b/src/user/lib/libc/start.c
@@ -1,18 +1,28 @@
 #include <tce/syscall.h>
 
-extern int main(char **args);
+#include <stdio.h>
+
+extern int main(int argc, char **argv);
 
 extern size_t start_ctors, end_ctors, start_dtors, end_dtors;
 
-void start(char **args) {
-	size_t *call;
+void __tce_libc_start(char **args) {
+	// setup stdio
+	term.fd = 0;
+	__tce_libc_fsetup(&term);
 
+	// call C++ static constructors
+	size_t *call;
 	for (call = &start_ctors; call < &end_ctors; call++) {
 		((void(*)(void))*call)();
 	}
 	
-	int ret = main(args);
+	// call main
+	char **lastarg = args;
+	while (*lastarg) lastarg++;
+	int ret = main((lastarg - args), args);
 
+	// call C++ static destructors
 	for (call = &start_dtors; call < &end_dtors; call++) {
 		((void(*)(void))*call)();
 	}
diff --git a/src/user/lib/libc/std/ctype.c b/src/user/lib/libc/std/ctype.c
new file mode 100644
index 0000000..f0e7750
--- /dev/null
+++ b/src/user/lib/libc/std/ctype.c
@@ -0,0 +1,28 @@
+#include <ctype.h>
+
+
+int isalpha(int c) {
+	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
+}
+
+int isdigit(int c) {
+	return (c >= '0' && c <= '9');
+}
+
+int isalnum(int c) {
+	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9');
+}
+
+int tolower(int c) {
+	if (c >= 'A' && c <= 'Z') {
+		return c + ('a' - 'A');
+	}
+	return c;
+}
+
+int toupper(int c) {
+	if (c >= 'a' && c <= 'z') {
+		return c - ('a' - 'A');
+	}
+	return c;
+}
diff --git a/src/user/lib/libc/std/readline.c b/src/user/lib/libc/std/readline.c
index 50e4f0d..4177bf6 100644
--- a/src/user/lib/libc/std/readline.c
+++ b/src/user/lib/libc/std/readline.c
@@ -1,15 +1,14 @@
 #include <readline.h>
 #include <stdlib.h>
 
-char* freadln(FILE f) {
-	fprint(f, "\x1b[e");	// enable keyboard echo
+char* freadln(FILE *f) {
 	int i;
 
 	char *p = (char*)malloc(256);
 	char *b = p;
 
 	while (1) {
-		int l = read(f, 0, 255, b);
+		int l = fread(b, 255, 1, f);
 		if (l < 0) {
 			free(b);
 			return 0;
@@ -36,15 +35,14 @@ char* freadln(FILE f) {
 }
 
 char* readln() {
-	return freadln(term);
+	return freadln(&term);
 }
 
 
 // ** READLINE
 
-char *freadline(FILE f, readline_history *h) {
+char *freadline(FILE *f, readline_history *h) {
 	int i;
-	fprint(f, "\x1b[h");	// disable keyboard echo
 
 	if (h->str == 0) {
 		h->str = (char**)malloc(h->max * sizeof(char*));
@@ -78,12 +76,15 @@ char *freadline(FILE f, readline_history *h) {
 		int te = cur - str;
 
 		char buf[16];
-		int l = read(f, 0, 16, buf);
+		int l = fread(buf, 16, 1, f);
 		if (l < 0) return 0;
 
 		char *in = buf;
 		while (in < buf + l) {
-			if (*in == 27) {
+			if (*in == 4) {				// eot
+				fprintf(f, "^D\n");
+				return 0;
+			} else if (*in == 27) {
 				in++;
 				if (*in == '[') {
 					in++;
@@ -142,7 +143,7 @@ char *freadline(FILE f, readline_history *h) {
 		
 		
 		if (finished) {
-			fprintf(f, "\n");
+			fprint(f, "\n");
 
 			if (h->str[h->n-1] != str) h->n--;
 
diff --git a/src/user/lib/libc/std/setjmp.asm b/src/user/lib/libc/std/setjmp.asm
new file mode 100644
index 0000000..399ad0c
--- /dev/null
+++ b/src/user/lib/libc/std/setjmp.asm
@@ -0,0 +1,37 @@
+[GLOBAL setjmp]
+setjmp:
+	mov edx, [esp + 4]		; read jmp_buf pointer into edx
+	mov eax, [esp]			; read return address into eax
+
+	mov [edx], ebp
+	mov [edx+4], ebx
+	mov [edx+8], edi
+	mov [edx+12], esi
+	mov [edx+16], esp
+	mov [edx+20], eax
+
+	xor eax, eax			; return 0
+	ret
+
+[GLOBAL longjmp]
+longjmp:
+	mov edx, [esp + 4]		; read jmp_buf pointer into edx
+	mov eax, [esp + 8]		; move return value into eax
+	
+	; make sure eax is not 0
+	cmp eax, 0
+	jne next
+	inc eax					; eax is 0, set it to 1
+
+next: 
+	mov esp, [edx + 16]		; read esp
+	mov ebx, [edx + 20]		; read return address
+	mov [esp], ebx			; update return address
+
+	mov ebp, [edx]
+	mov ebx, [edx + 4]
+	mov edi, [edx + 8]
+	mov esi, [edx + 12]
+
+	ret
+
diff --git a/src/user/lib/libc/std/stdio.c b/src/user/lib/libc/std/stdio.c
index 12064be..be65505 100644
--- a/src/user/lib/libc/std/stdio.c
+++ b/src/user/lib/libc/std/stdio.c
@@ -1,37 +1,258 @@
+#include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <tce/syscall.h>
-#include <readline.h>
+#include <ctype.h>
 
-FILE term = 0;
-void print(const char *s) {
-	fprint(term, s);
+FILE term;
+
+
+// GENERAL FILE ROUTINES
+
+FILE *fopen(const char *path, const char *mode) {
+	int m = 0;
+	if (strchr(mode, 'r')) m |= FM_READ;
+	if (strchr(mode, 'w')) m |= FM_WRITE;
+	if (strchr(mode, 't')) m |= FM_TRUNC;
+	if (strchr(mode, 'c')) m |= FM_CREATE;
+
+	FILE *ret = malloc(sizeof(FILE));
+	if (!ret) return NULL;
+
+	ret->fd = open(path, m);
+	if (ret->fd < 0) {
+		errno = ret->fd;
+		free(ret);
+		return NULL;
+	}
+	__tce_libc_fsetup(ret);
+
+	return ret;
+}
+
+void __tce_libc_fsetup(FILE *f) {
+	statf(f->fd, &f->info);
+	f->pos = 0;
+
+	if (f->info.type & FT_TERMINAL) {
+		f->pos = -1;
+
+		f->tib_begin = malloc(TERM_INPUT_BUFFER_SIZE);
+		f->tib_end = f->tib_begin + TERM_INPUT_BUFFER_SIZE;
+		f->tib_u_begin = f->tib_begin;
+		f->tib_u_end = f->tib_u_begin;
+		f->term_echo = 1;
+	}
+}
+
+int fgetc(FILE *f) {
+	if ((f->info.type & FT_TERMINAL) && f->tib_begin) {
+		if (f->tib_u_end == f->tib_u_begin) {
+			f->tib_u_begin = f->tib_u_end = f->tib_begin;
+			// read one line into buffer
+			int cont = 1;
+			while (cont) {
+				int k;
+				int n = read(f->fd, 0, f->tib_end - f->tib_u_end, f->tib_u_end);
+				for (k = 0; k < n; k++) {
+					if (f->term_echo) fprintf(f, "%c", f->tib_u_end[k]);
+					if (f->tib_u_end[k] == '\n' || f->tib_u_end[k] == 4) cont = 0;
+				}
+				f->tib_u_end += k;
+				if (f->tib_u_end == f->tib_end) cont = 0;
+			}
+
+		}
+
+		if (f->tib_u_end > f->tib_u_begin) {
+			char c = *f->tib_u_begin;
+			f->tib_u_begin++;
+			if (f->tib_u_begin == f->tib_end) {
+				f->tib_u_begin = f->tib_u_end = f->tib_begin;	// empty buffer
+			}
+			return c;
+		}
+	} else {
+		char c;
+		int r = read(f->fd, (f->pos == -1 ? 0 : f->pos), 1, &c);
+		if (r == 1) {
+			if (f->pos != -1) f->pos++;
+			return c;
+		}
+	}
+	return EOF;
+}
+
+int ungetc(int c, FILE *f) {
+	if (f->info.type & FT_TERMINAL && f->tib_begin) {
+		if (f->tib_u_begin > f->tib_begin) {
+			// buffer contains data which is partially read already
+			f->tib_u_begin--;
+			*(f->tib_u_begin) = c;
+		} else if (f->tib_u_end == f->tib_u_begin) {
+			// buffer is totally empty
+			*(f->tib_u_end) = c;
+			f->tib_u_end++;
+		} else {
+			return EOF;		// no space in buffer.
+		}
+	} else if (f->pos >0) {
+		f->pos--;
+	} else {
+		return EOF;
+	}
+	return c;
+}
+
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE* f) {
+	if (size * nmemb == 0) return 0;
+
+	int r = read(f->fd, (f->pos == -1 ? 0 : f->pos), size * nmemb, ptr);
+	if (r > 0) {
+		if (f->pos != -1) f->pos += r;
+		return r;
+	} else {
+		errno = r;
+		return 0;
+	}
+}
+
+size_t fwrite(void *ptr, size_t size, size_t nmemb, FILE *f) {
+	if (size * nmemb == 0) return 0;
+	int r = write(f->fd, (f->pos == -1 ? 0 : f->pos), size * nmemb, ptr);
+	if (r > 0) {
+		if (f->pos != -1) f->pos += r;
+		return r;
+	} else {
+		errno = r;
+		return 0;
+	}
+}
+
+size_t fseek(FILE *f, long offset, int whence) {
+	// Update info
+	statf(f->fd, &f->info);
+
+	if (!(f->info.type & FT_FILE)) {
+		errno = EBADF;
+		return -1;
+	}
+
+	if (whence == SEEK_CUR) {
+		offset += f->pos;
+	}
+	if (whence == SEEK_END) {
+		offset = f->info.size - offset;
+	}
+
+	if (offset > f->info.size || offset < 0) {
+		errno = EINVAL;
+		return -1;
+	}
+	f->pos = offset;
+
+	return 0;
+}
+
+long ftell(FILE *f) {
+	return f->pos;
+}
+
+void fclose(FILE *f) {
+	if (f->tib_begin) free(f->tib_begin);
+	close(f->fd);
+	free(f);
+}
+
+// COMFY INPUT FUNCTIONS
+
+int getchar() {
+	return fgetc(&term);
+}
+
+int scanf(const char *format, ...) {
+	// rudimentary implementation
+	int r = 0; 
+
+	va_list ap;
+	va_start(ap, format);
+
+	while (*format) {
+		if (*format == '%') {
+			format++;
+			if (!(*format)) break;
+
+			if (*format == 'd' || *format == 'i') {
+				int c = fgetc(&term);
+
+				int *ret = va_arg(ap, int*);
+				*ret = 0;
+
+				while (isdigit(c)) {
+					(*ret) *= 10;
+					(*ret) += (c - '0');
+					r++;
+					c = fgetc(&term);
+				}
+				ungetc(c, &term);
+			} else if (*format == 'c') {
+				char *c = va_arg(ap, char*);
+				*c = fgetc(&term);
+				r++;
+			}
+			format++;
+		} else {
+			int c = fgetc(&term);
+			if (c == *format) {
+				r++;
+				format++;
+			} else {
+				ungetc(c, &term);
+				break;
+			}
+		}
+	}
+
+	va_end(ap);
+	return r;
+}
+
+// COMFY OUTPUT FUNCTIONS
+
+int print(const char *s) {
+	fprint(&term, s);
+	return strlen(s);
 }
 
-void printf(const char *format,  ...) {
+int printf(const char *format,  ...) {
 	va_list ap;
+	int l;
 	va_start(ap, format);
-	vfprintf(term, format, ap);
+	l = vfprintf(&term, format, ap);
 	va_end(ap);
+	return l;
 }
 
-void fprint(FILE f, const char *s) {
-	write(f, 0, strlen(s), s);
+int fprint(FILE *f, const char *s) {
+	return fwrite((void*)s, strlen(s), 1, f);
 }
 
-void fprintf(FILE f, const char* format, ...) {
+int fprintf(FILE *f, const char* format, ...) {
 	va_list ap;
+	int l;
 	va_start(ap, format);
-	vfprintf(f, format, ap);
+	l = vfprintf(f, format, ap);
 	va_end(ap);
+	return l;
 }
 
-void vfprintf(FILE f, const char *fmt, va_list ap) {
+int vfprintf(FILE *f, const char *fmt, va_list ap) {
 	va_list ap2;
 	va_copy(ap2, ap);
 	int l = printf_str_len(fmt, ap2);
 	va_end(ap2);
 	char buf[l+1];
 	l = vsprintf(buf, fmt, ap);
-	if (l > 0) write(f, 0, l, buf);
+	if (l > 0) return fwrite(buf, l, 1, f);
+	return 0;
 }
diff --git a/src/user/lib/libc/std/stdlib.c b/src/user/lib/libc/std/stdlib.c
index 9d46b5c..15f9ddc 100644
--- a/src/user/lib/libc/std/stdlib.c
+++ b/src/user/lib/libc/std/stdlib.c
@@ -1,8 +1,38 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <ctype.h>
 
 volatile int errno;
 
+void exit(int k) {
+	process_exit(k);
+}
+
 void abort() {
-	process_exit(100 + errno);
+	process_exit(300 + errno);
+}
+
+
+// Random generator
+
+static unsigned int rnd;
+
+void srand(unsigned int l) {
+	rnd = l;
+}
+
+int rand() {
+    rnd = rnd * 1103515245 + 12345;
+    return (unsigned int)(rnd / 65536) % (RAND_MAX + 1);
+}
+
+// ASCII to int
+
+int atoi(char *s) {
+	int r = 0;
+	while (*s >= '0' && *s <= '9') {
+		r *= 10;
+		r += (*s) - '0';
+	};
+	return r;
 }
diff --git a/src/user/lib/libc/std/string.c b/src/user/lib/libc/std/string.c
index 619b8c6..02225a6 100644
--- a/src/user/lib/libc/std/string.c
+++ b/src/user/lib/libc/std/string.c
@@ -17,7 +17,18 @@ char *strchr(const char *str, int c) {
 
 char *strcpy(char *dest, const char *src) {
 	memcpy(dest, src, strlen(src) + 1);
-	return (char*)src;
+	return (char*)dest;
+}
+
+char *strncpy(char *dest, const char *src, int n) {
+	size_t i;
+
+	for (i = 0; i < n && src[i] != '\0'; i++)
+		dest[i] = src[i];
+	for ( ; i < n; i++)
+		dest[i] = '\0';
+
+	return dest;
 }
 
 char *strdup(const char *src) {
@@ -29,11 +40,10 @@ char *strdup(const char *src) {
 
 char *strcat(char *dest, const char *src) {
 	char *dest2 = dest;
-	dest2 += strlen(dest) - 1;
+	while (*dest2) dest2++;	// move to end of string
+
 	while (*src) {
-		*dest2 = *src;
-		src++;
-		dest2++;
+		*(dest2++) = *(src++);
 	}
 	*dest2 = 0;
 	return dest;
@@ -133,6 +143,8 @@ int printf_str_len(const char *format, va_list ap) {
 				va_arg(ap, void*);
 			} else if (*format == 's') {
 				l += strlen(va_arg(ap, const char*));
+			} else if (*format == 'c') {
+				l += 1;
 			}
 		} else {
 			l++;
@@ -164,6 +176,10 @@ int vsprintf(char *buf, const char *format, va_list ap) {
 				const char *s = va_arg(ap, const char*);
 				strcpy(end, s);
 				end += strlen(s);
+			} else if (*format == 'c') {
+				char k = va_arg(ap, int);
+				*(end++) = k;
+				*end = 0;
 			}
 			format++;
 		} else {
@@ -173,3 +189,90 @@ int vsprintf(char *buf, const char *format, va_list ap) {
 	*end = 0;
 	return end - buf;
 }
+
+
+// ****** PATH CONCATENATION FUNCTION *******
+
+
+void simplify_path(char* p) {
+	char *it = p;
+	char *member = it;
+	while (*it != 0) {
+		if (*it == '/') {
+			if (it == member && it != p) {
+				// two consecutive slashes
+				char *i = member;
+				while (1) {
+					i[0] = i[1];
+					if (i[0] == 0) break;
+					i++;
+				}
+			} else {
+				*it = 0;
+				if (strcmp(member, ".") == 0) {
+					char *i = member;
+					while (1) {
+						i[0] = i[2];
+						if (i[0] == 0) break;
+						i++;
+					}
+				} else if (strcmp(member, "..") == 0) {
+					*it = '/';
+					char* start = member - 2;
+					char* next = member + 3;
+					while (start > p && *start != '/') {
+						start--;
+					}
+					start++;
+					it = member = start;
+					while (1) {
+						*start = *next;
+						if (*start == 0) break;
+						start++;
+						next++;
+					}
+				} else {
+					*it = '/';
+					it++;
+					member = it;
+				}
+			}
+		} else {
+			it++;
+		}
+	}
+}
+
+char* path_cat(const char *a, const char *b, int trailing_slash) {
+	int len, la = strlen(a), lb = strlen(b);
+	if (b[0] == '/') {
+		len = lb + 2;
+	} else {
+		len = la + lb + 3;
+	}
+	char *buf = malloc(len + 1);
+	if (b[0] == '/') {
+		memcpy(buf, b, lb);
+		if (buf[lb-1] != '/') {
+			buf[lb++] = '/';
+		}
+		buf[lb] = 0;
+	} else {
+		memcpy(buf, a, la);
+		if (buf[la-1] != '/') {
+			buf[la++] = '/';
+		}
+		memcpy(buf + la, b, lb);
+		if (buf[la + lb - 1] != '/') {
+			buf[la + lb] = '/';
+			lb++;
+		}
+		buf[la + lb] = 0;
+	}
+	simplify_path(buf);
+	if (!trailing_slash) {
+		int l = strlen(buf);
+		if (buf[l-1] == '/') buf[l-1] = 0;
+	}
+	return buf;
+}
diff --git a/src/user/lib/libc/tce/syscall.c b/src/user/lib/libc/tce/syscall.c
index acdcc51..f4f1333 100644
--- a/src/user/lib/libc/tce/syscall.c
+++ b/src/user/lib/libc/tce/syscall.c
@@ -75,7 +75,7 @@ void brk(void* ptr) {
 
 // ********** proc
 
-int run(const char* filename, const char** args, FILE zero_fd) {
+int run(const char* filename, const char** args, int zero_fd) {
 	return call(SC_RUN, (unsigned)filename, (unsigned)args, (unsigned)zero_fd, 0, 0);
 }
 
@@ -85,36 +85,36 @@ int waitpid(int p, int block) {
 
 // ********** file
 
-FILE open(const char* filename, int mode) {
+int open(const char* filename, int mode) {
 	return call(SC_OPEN, (unsigned)filename, mode, 0, 0, 0);
 }
 
-FILE open_relative(FILE root, const char* filename, int mode) {
-	return call(SC_OPEN_RELATIVE, root, (unsigned) filename, mode, 0, 0);
+int open_relative(int root_fd, const char* filename, int mode) {
+	return call(SC_OPEN_RELATIVE, root_fd, (unsigned) filename, mode, 0, 0);
 }
 
 int stat(const char* filename, file_info *info) {
 	return call(SC_STAT, (unsigned) filename, (unsigned) info, 0, 0, 0);
 }
 
-int stat_relative(FILE root, const char* filename, file_info *info) {
-	return call(SC_STAT_RELATIVE, root, (unsigned) filename, (unsigned) info, 0, 0);
+int stat_relative(int root_fd, const char* filename, file_info *info) {
+	return call(SC_STAT_RELATIVE, root_fd, (unsigned) filename, (unsigned) info, 0, 0);
 }
 
-int statf(FILE file, file_info *info) {
-	return call(SC_STATF, file, (unsigned)info, 0, 0, 0);
+int statf(int file_fd, file_info *info) {
+	return call(SC_STATF, file_fd, (unsigned)info, 0, 0, 0);
 }
 
-void close(FILE file) {
-	call(SC_CLOSE, file, 0, 0, 0, 0);
+void close(int fd) {
+	call(SC_CLOSE, fd, 0, 0, 0, 0);
 }
 
-int read(FILE file, size_t offset, size_t len, char *buffer) {
-	return call(SC_READ, file, offset, len, (unsigned) buffer, 0);
+int read(int fd, size_t offset, size_t len, char *buffer) {
+	return call(SC_READ, fd, offset, len, (unsigned) buffer, 0);
 }
 
-int write(FILE file, size_t offset, size_t len, const char* buffer) {
-	return call(SC_WRITE, file, offset, len, (unsigned) buffer, 0);
+int write(int fd, size_t offset, size_t len, const char* buffer) {
+	return call(SC_WRITE, fd, offset, len, (unsigned) buffer, 0);
 }
 
 int link(const char* from, const char* to, int mode) {