Added fchdir() system call, with corresponding manpage, Changelog and

system include modifications.

include/minix/callnr.h

@@ -1,4 +1,4 @@
-#define NCALLS		  86	/* number of system calls allowed */
+#define NCALLS		  87	/* number of system calls allowed */
 
 #define EXIT		   1 
 #define FORK		   2 
@@ -74,3 +74,4 @@
 #define ALLOCMEM	  83	/* to PM */
 #define FREEMEM		  84	/* to PM */
 #define SELECT            85	/* to FS */
+#define FCHDIR            86	/* to FS */

include/unistd.h

@@ -85,6 +85,7 @@ _PROTOTYPE( void _exit, (int _status)					);
 _PROTOTYPE( int access, (const char *_path, int _amode)			);
 _PROTOTYPE( unsigned int alarm, (unsigned int _seconds)			);
 _PROTOTYPE( int chdir, (const char *_path)				);
+_PROTOTYPE( int fchdir, (int fd)					);
 _PROTOTYPE( int chown, (const char *_path, _mnx_Uid_t _owner, _mnx_Gid_t _group)	);
 _PROTOTYPE( int close, (int _fd)					);
 _PROTOTYPE( char *ctermid, (char *_s)					);

lib/posix/_chdir.c

@@ -10,3 +10,13 @@ _CONST char *name;
   _loadname(name, &m);
   return(_syscall(FS, CHDIR, &m));
 }
+
+PUBLIC int fchdir(fd)
+int fd;
+{
+  message m;
+
+  m.m1_i1 = fd;
+  return(_syscall(FS, FCHDIR, &m));
+}
+

man/man2/chdir.2

@@ -7,18 +7,22 @@
 .TH CHDIR 2 "August 26, 1985"
 .UC 4
 .SH NAME
-chdir \- change current working directory
+chdir, fchdir \- change current working directory
 .SH SYNOPSIS
 .nf
 .ft B
 #include <unistd.h>
 
 int chdir(const char *\fIpath\fP)
+int fchdir(int \fIfd\fP)
 .ft R
 .fi
 .SH DESCRIPTION
 .I Path
 is the pathname of a directory.
+.I Fd
+is the file descriptor of a directory.
+
 .B Chdir
 causes this directory
 to become the current working directory,

servers/fs/proto.h

@@ -142,6 +142,7 @@ _PROTOTYPE( zone_t rd_indir, (struct buf *bp, int index)		);
 
 /* stadir.c */
 _PROTOTYPE( int do_chdir, (void)					);
+_PROTOTYPE( int do_fchdir, (void)					);
 _PROTOTYPE( int do_chroot, (void)					);
 _PROTOTYPE( int do_fstat, (void)					);
 _PROTOTYPE( int do_stat, (void)						);

servers/fs/stadir.c

@@ -20,9 +20,24 @@
 #include "super.h"
 
 FORWARD _PROTOTYPE( int change, (struct inode **iip, char *name_ptr, int len));
+FORWARD _PROTOTYPE( int change_into, (struct inode **iip, struct inode *ip));
 FORWARD _PROTOTYPE( int stat_inode, (struct inode *rip, struct filp *fil_ptr,
 			char *user_addr)				);
 
+/*===========================================================================*
+ *				do_fchdir				     *
+ *===========================================================================*/
+PUBLIC int do_fchdir()
+{
+	/* Change directory on already-opened fd. */
+	struct filp *rfilp;
+
+	/* Is the file descriptor valid? */
+	if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
+
+	return change_into(&fp->fp_workdir, rfilp->filp_ino);
+}
+
 /*===========================================================================*
  *				do_chdir				     *
  *===========================================================================*/
@@ -86,13 +101,22 @@ char *name_ptr;			/* pointer to the directory name to change to */
 int len;			/* length of the directory name string */
 {
 /* Do the actual work for chdir() and chroot(). */
-
   struct inode *rip;
-  register int r;
 
   /* Try to open the new directory. */
   if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
   if ( (rip = eat_path(user_path)) == NIL_INODE) return(err_code);
+  return change_into(iip, rip);
+}
+
+/*===========================================================================*
+ *				change_into					     *
+ *===========================================================================*/
+PRIVATE int change_into(iip, rip)
+struct inode **iip;		/* pointer to the inode pointer for the dir */
+struct inode *rip;		/* this is what the inode has to become */
+{
+  register int r;
 
   /* It must be a directory and also be searchable. */
   if ( (rip->i_mode & I_TYPE) != I_DIRECTORY)
@@ -112,7 +136,6 @@ int len;			/* length of the directory name string */
   return(OK);
 }
 
-
 /*===========================================================================*
  *				do_stat					     *
  *===========================================================================*/

servers/fs/table.c

@@ -103,6 +103,7 @@ PUBLIC _PROTOTYPE (int (*call_vec[]), (void) ) = {
 	no_sys,		/* 83 = memalloc */
 	no_sys,		/* 84 = memfree */
 	do_select,	/* 85 = select */
+	do_fchdir,	/* 86 = fchdir */
 };
 /* This should not fail with "array size is negative": */
 extern int dummy[sizeof(call_vec) == NCALLS * sizeof(call_vec[0]) ? 1 : -1];

servers/pm/table.c

@@ -102,6 +102,7 @@ _PROTOTYPE (int (*call_vec[NCALLS]), (void) ) = {
 	do_allocmem, 	/* 83 = memalloc */
 	do_freemem, 	/* 84 = memfree */
 	no_sys,		/* 85 = select */
+	no_sys,		/* 86 = fchdir */
 };
 /* This should not fail with "array size is negative": */
 extern int dummy[sizeof(call_vec) == NCALLS * sizeof(call_vec[0]) ? 1 : -1];