1 /* This file contains the code for performing four system calls relating to
2 * status and directories.
3 *
4 * The entry points into this file are
5 * do_chdir: perform the CHDIR system call
6 * do_chroot: perform the CHROOT system call
7 * do_stat: perform the STAT system call
8 * do_fstat: perform the FSTAT system call
9 */
10
11 #include "fs.h"
12 #include <sys/stat.h>
13 #include "file.h"
14 #include "fproc.h"
15 #include "inode.h"
16 #include "param.h"
17
18 FORWARD _PROTOTYPE( int change, (struct inode **iip, char *name_ptr, int len));
19 FORWARD _PROTOTYPE( int stat_inode, (struct inode *rip, struct filp *fil_ptr,
20 char *user_addr) );
21
22 /*===========================================================================*
23 * do_chdir *
24 *===========================================================================*/
25 PUBLIC int do_chdir()
26 {
27 /* Change directory. This function is also called by MM to simulate a chdir
28 * in order to do EXEC, etc. It also changes the root directory, the uids and
29 * gids, and the umask.
30 */
31
32 int r;
33 register struct fproc *rfp;
34
35 if (who == MM_PROC_NR) {
36 rfp = &fproc[slot1];
37 put_inode(fp->fp_rootdir);
38 dup_inode(fp->fp_rootdir = rfp->fp_rootdir);
39 put_inode(fp->fp_workdir);
40 dup_inode(fp->fp_workdir = rfp->fp_workdir);
41
42 /* MM uses access() to check permissions. To make this work, pretend
43 * that the user's real ids are the same as the user's effective ids.
44 * FS calls other than access() do not use the real ids, so are not
45 * affected.
46 */
47 fp->fp_realuid =
48 fp->fp_effuid = rfp->fp_effuid;
49 fp->fp_realgid =
50 fp->fp_effgid = rfp->fp_effgid;
51 fp->fp_umask = rfp->fp_umask;
52 return(OK);
53 }
54
55 /* Perform the chdir(name) system call. */
56 r = change(&fp->fp_workdir, name, name_length);
57 return(r);
58 }
59
60
61 /*===========================================================================*
62 * do_chroot *
63 *===========================================================================*/
64 PUBLIC int do_chroot()
65 {
66 /* Perform the chroot(name) system call. */
67
68 register int r;
69
70 if (!super_user) return(EPERM); /* only su may chroot() */
71 r = change(&fp->fp_rootdir, name, name_length);
72 return(r);
73 }
74
75
76 /*===========================================================================*
77 * change *
78 *===========================================================================*/
79 PRIVATE int change(iip, name_ptr, len)
80 struct inode **iip; /* pointer to the inode pointer for the dir */
81 char *name_ptr; /* pointer to the directory name to change to */
82 int len; /* length of the directory name string */
83 {
84 /* Do the actual work for chdir() and chroot(). */
85
86 struct inode *rip;
87 register int r;
88
89 /* Try to open the new directory. */
90 if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
91 if ( (rip = eat_path(user_path)) == NIL_INODE) return(err_code);
92
93 /* It must be a directory and also be searchable. */
94 if ( (rip->i_mode & I_TYPE) != I_DIRECTORY)
95 r = ENOTDIR;
96 else
97 r = forbidden(rip, X_BIT); /* check if dir is searchable */
98
99 /* If error, return inode. */
100 if (r != OK) {
101 put_inode(rip);
102 return(r);
103 }
104
105 /* Everything is OK. Make the change. */
106 put_inode(*iip); /* release the old directory */
107 *iip = rip; /* acquire the new one */
108 return(OK);
109 }
110
111
112 /*===========================================================================*
113 * do_stat *
114 *===========================================================================*/
115 PUBLIC int do_stat()
116 {
117 /* Perform the stat(name, buf) system call. */
118
119 register struct inode *rip;
120 register int r;
121
122 /* Both stat() and fstat() use the same routine to do the real work. That
123 * routine expects an inode, so acquire it temporarily.
124 */
125 if (fetch_name(name1, name1_length, M1) != OK) return(err_code);
126 if ( (rip = eat_path(user_path)) == NIL_INODE) return(err_code);
127 r = stat_inode(rip, NIL_FILP, name2); /* actually do the work.*/
128 put_inode(rip); /* release the inode */
129 return(r);
130 }
131
132
133 /*===========================================================================*
134 * do_fstat *
135 *===========================================================================*/
136 PUBLIC int do_fstat()
137 {
138 /* Perform the fstat(fd, buf) system call. */
139
140 register struct filp *rfilp;
141
142 /* Is the file descriptor valid? */
143 if ( (rfilp = get_filp(fd)) == NIL_FILP) return(err_code);
144
145 return(stat_inode(rfilp->filp_ino, rfilp, buffer));
146 }
147
148
149 /*===========================================================================*
150 * stat_inode *
151 *===========================================================================*/
152 PRIVATE int stat_inode(rip, fil_ptr, user_addr)
153 register struct inode *rip; /* pointer to inode to stat */
154 struct filp *fil_ptr; /* filp pointer, supplied by 'fstat' */
155 char *user_addr; /* user space address where stat buf goes */
156 {
157 /* Common code for stat and fstat system calls. */
158
159 struct stat statbuf;
160 mode_t mo;
161 int r, s;
162
163 /* Update the atime, ctime, and mtime fields in the inode, if need be. */
164 if (rip->i_update) update_times(rip);
165
166 /* Fill in the statbuf struct. */
167 mo = rip->i_mode & I_TYPE;
168 s = (mo == I_CHAR_SPECIAL || mo == I_BLOCK_SPECIAL); /* true iff special */
169 statbuf.st_dev = rip->i_dev;
170 statbuf.st_ino = rip->i_num;
171 statbuf.st_mode = rip->i_mode;
172 statbuf.st_nlink = rip->i_nlinks & BYTE;
173 statbuf.st_uid = rip->i_uid;
174 statbuf.st_gid = rip->i_gid & BYTE;
175 statbuf.st_rdev = (dev_t) (s ? rip->i_zone[0] : NO_DEV);
176 statbuf.st_size = rip->i_size;
177
178 if (rip->i_pipe == I_PIPE) {
179 statbuf.st_mode &= ~I_REGULAR; /* wipe out I_REGULAR bit for pipes */
180 if (fil_ptr != NIL_FILP && fil_ptr->filp_mode & R_BIT)
181 statbuf.st_size -= fil_ptr->filp_pos;
182 }
183
184 statbuf.st_atime = rip->i_atime;
185 statbuf.st_mtime = rip->i_mtime;
186 statbuf.st_ctime = rip->i_ctime;
187
188 /* Copy the struct to user space. */
189 r = sys_copy(FS_PROC_NR, D, (phys_bytes) &statbuf,
190 who, D, (phys_bytes) user_addr, (phys_bytes) sizeof(statbuf));
191 return(r);
192 }
193
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