12685309fSrsc #include "types.h" 2558ab49fSrsc #include "defs.h" 32685309fSrsc #include "param.h" 4558ab49fSrsc #include "stat.h" 52685309fSrsc #include "mmu.h" 62685309fSrsc #include "proc.h" 72685309fSrsc #include "fs.h" 89936bffaSrsc #include "file.h" 92685309fSrsc #include "fcntl.h" 102685309fSrsc 11224f6598Srsc // Fetch the nth word-sized system call argument as a file descriptor 12224f6598Srsc // and return both the descriptor and the corresponding struct file. 13224f6598Srsc static int 1464c47374Srsc argfd(int n, int *pfd, struct file **pf) 15224f6598Srsc { 16224f6598Srsc int fd; 17224f6598Srsc struct file *f; 18224f6598Srsc 193a2310f7Srsc if(argint(n, &fd) < 0) 20224f6598Srsc return -1; 2148755214SRuss Cox if(fd < 0 || fd >= NOFILE || (f=proc->ofile[fd]) == 0) 22224f6598Srsc return -1; 23224f6598Srsc if(pfd) 24224f6598Srsc *pfd = fd; 25224f6598Srsc if(pf) 26224f6598Srsc *pf = f; 27224f6598Srsc return 0; 28224f6598Srsc } 29224f6598Srsc 30224f6598Srsc // Allocate a file descriptor for the given file. 31224f6598Srsc // Takes over file reference from caller on success. 32224f6598Srsc static int 33224f6598Srsc fdalloc(struct file *f) 34224f6598Srsc { 35224f6598Srsc int fd; 369583b476Srsc 37224f6598Srsc for(fd = 0; fd < NOFILE; fd++){ 3848755214SRuss Cox if(proc->ofile[fd] == 0){ 3948755214SRuss Cox proc->ofile[fd] = f; 40224f6598Srsc return fd; 41224f6598Srsc } 42224f6598Srsc } 43224f6598Srsc return -1; 44224f6598Srsc } 45224f6598Srsc 462685309fSrsc int 47f9a06440SRuss Cox sys_dup(void) 48f9a06440SRuss Cox { 49f9a06440SRuss Cox struct file *f; 50f9a06440SRuss Cox int fd; 51f9a06440SRuss Cox 52f9a06440SRuss Cox if(argfd(0, 0, &f) < 0) 53f9a06440SRuss Cox return -1; 54f9a06440SRuss Cox if((fd=fdalloc(f)) < 0) 55f9a06440SRuss Cox return -1; 56f9a06440SRuss Cox filedup(f); 57f9a06440SRuss Cox return fd; 58f9a06440SRuss Cox } 59f9a06440SRuss Cox 60f9a06440SRuss Cox int 61eaea18cbSrsc sys_read(void) 622685309fSrsc { 63eaea18cbSrsc struct file *f; 64eaea18cbSrsc int n; 65666f58c7Srsc char *p; 662685309fSrsc 67666f58c7Srsc if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) 682685309fSrsc return -1; 69666f58c7Srsc return fileread(f, p, n); 702685309fSrsc } 712685309fSrsc 722685309fSrsc int 732685309fSrsc sys_write(void) 742685309fSrsc { 75224f6598Srsc struct file *f; 76224f6598Srsc int n; 77666f58c7Srsc char *p; 782685309fSrsc 79666f58c7Srsc if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) 802685309fSrsc return -1; 81666f58c7Srsc return filewrite(f, p, n); 822685309fSrsc } 832685309fSrsc 842685309fSrsc int 852685309fSrsc sys_close(void) 862685309fSrsc { 872685309fSrsc int fd; 88224f6598Srsc struct file *f; 892685309fSrsc 90224f6598Srsc if(argfd(0, &fd, &f) < 0) 912685309fSrsc return -1; 9248755214SRuss Cox proc->ofile[fd] = 0; 93224f6598Srsc fileclose(f); 942685309fSrsc return 0; 952685309fSrsc } 962685309fSrsc 978d2e9a48Srsc int 988d2e9a48Srsc sys_fstat(void) 998d2e9a48Srsc { 1008d2e9a48Srsc struct file *f; 1018d2e9a48Srsc struct stat *st; 1028d2e9a48Srsc 1038d2e9a48Srsc if(argfd(0, 0, &f) < 0 || argptr(1, (void*)&st, sizeof(*st)) < 0) 1048d2e9a48Srsc return -1; 1058d2e9a48Srsc return filestat(f, st); 1068d2e9a48Srsc } 1078d2e9a48Srsc 108eaea18cbSrsc // Create the path new as a link to the same inode as old. 109eaea18cbSrsc int 110eaea18cbSrsc sys_link(void) 111eaea18cbSrsc { 112eaea18cbSrsc char name[DIRSIZ], *new, *old; 113eaea18cbSrsc struct inode *dp, *ip; 114eaea18cbSrsc 115eaea18cbSrsc if(argstr(0, &old) < 0 || argstr(1, &new) < 0) 116eaea18cbSrsc return -1; 11707090dd7Srsc if((ip = namei(old)) == 0) 118eaea18cbSrsc return -1; 11907090dd7Srsc ilock(ip); 120eaea18cbSrsc if(ip->type == T_DIR){ 12107090dd7Srsc iunlockput(ip); 122eaea18cbSrsc return -1; 123eaea18cbSrsc } 124*2e590463SRobert Morris 125*2e590463SRobert Morris begin_trans(); 126*2e590463SRobert Morris 127eaea18cbSrsc ip->nlink++; 128eaea18cbSrsc iupdate(ip); 12907090dd7Srsc iunlock(ip); 130eaea18cbSrsc 13107090dd7Srsc if((dp = nameiparent(new, name)) == 0) 13207090dd7Srsc goto bad; 13307090dd7Srsc ilock(dp); 134f3685aa3Srsc if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){ 135f3685aa3Srsc iunlockput(dp); 13607090dd7Srsc goto bad; 137f3685aa3Srsc } 13807090dd7Srsc iunlockput(dp); 13907090dd7Srsc iput(ip); 140*2e590463SRobert Morris 141*2e590463SRobert Morris commit_trans(); 142*2e590463SRobert Morris 14307090dd7Srsc return 0; 14407090dd7Srsc 14507090dd7Srsc bad: 14607090dd7Srsc ilock(ip); 147eaea18cbSrsc ip->nlink--; 148eaea18cbSrsc iupdate(ip); 14907090dd7Srsc iunlockput(ip); 150*2e590463SRobert Morris commit_trans(); 151eaea18cbSrsc return -1; 152eaea18cbSrsc } 153eaea18cbSrsc 154eaea18cbSrsc // Is the directory dp empty except for "." and ".." ? 155eaea18cbSrsc static int 156eaea18cbSrsc isdirempty(struct inode *dp) 157eaea18cbSrsc { 158eaea18cbSrsc int off; 159eaea18cbSrsc struct dirent de; 160eaea18cbSrsc 161eaea18cbSrsc for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){ 162eaea18cbSrsc if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 163eaea18cbSrsc panic("isdirempty: readi"); 164eaea18cbSrsc if(de.inum != 0) 165eaea18cbSrsc return 0; 166eaea18cbSrsc } 167eaea18cbSrsc return 1; 168eaea18cbSrsc } 169eaea18cbSrsc 1708d2e9a48Srsc //PAGEBREAK! 171eaea18cbSrsc int 172eaea18cbSrsc sys_unlink(void) 173eaea18cbSrsc { 174eaea18cbSrsc struct inode *ip, *dp; 175eaea18cbSrsc struct dirent de; 176eaea18cbSrsc char name[DIRSIZ], *path; 177eaea18cbSrsc uint off; 178eaea18cbSrsc 179eaea18cbSrsc if(argstr(0, &path) < 0) 180eaea18cbSrsc return -1; 18107090dd7Srsc if((dp = nameiparent(path, name)) == 0) 182eaea18cbSrsc return -1; 18307090dd7Srsc ilock(dp); 184eaea18cbSrsc 185eaea18cbSrsc // Cannot unlink "." or "..". 186eaea18cbSrsc if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0){ 18707090dd7Srsc iunlockput(dp); 188eaea18cbSrsc return -1; 189eaea18cbSrsc } 190eaea18cbSrsc 19107090dd7Srsc if((ip = dirlookup(dp, name, &off)) == 0){ 19207090dd7Srsc iunlockput(dp); 193eaea18cbSrsc return -1; 194eaea18cbSrsc } 19507090dd7Srsc ilock(ip); 196eaea18cbSrsc 197eaea18cbSrsc if(ip->nlink < 1) 198eaea18cbSrsc panic("unlink: nlink < 1"); 199eaea18cbSrsc if(ip->type == T_DIR && !isdirempty(ip)){ 20007090dd7Srsc iunlockput(ip); 20107090dd7Srsc iunlockput(dp); 202eaea18cbSrsc return -1; 203eaea18cbSrsc } 204eaea18cbSrsc 205*2e590463SRobert Morris begin_trans(); 206*2e590463SRobert Morris 207eaea18cbSrsc memset(&de, 0, sizeof(de)); 208eaea18cbSrsc if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 209eaea18cbSrsc panic("unlink: writei"); 21015a26936Skolya if(ip->type == T_DIR){ 21115a26936Skolya dp->nlink--; 21215a26936Skolya iupdate(dp); 21315a26936Skolya } 21407090dd7Srsc iunlockput(dp); 215eaea18cbSrsc 216eaea18cbSrsc ip->nlink--; 217eaea18cbSrsc iupdate(ip); 21807090dd7Srsc iunlockput(ip); 219*2e590463SRobert Morris 220*2e590463SRobert Morris commit_trans(); 221*2e590463SRobert Morris 222eaea18cbSrsc return 0; 223eaea18cbSrsc } 224eaea18cbSrsc 225eaea18cbSrsc static struct inode* 226f3685aa3Srsc create(char *path, short type, short major, short minor) 227eaea18cbSrsc { 228eaea18cbSrsc uint off; 229eaea18cbSrsc struct inode *ip, *dp; 230eaea18cbSrsc char name[DIRSIZ]; 231eaea18cbSrsc 23207090dd7Srsc if((dp = nameiparent(path, name)) == 0) 233eaea18cbSrsc return 0; 23407090dd7Srsc ilock(dp); 235eaea18cbSrsc 236f3685aa3Srsc if((ip = dirlookup(dp, name, &off)) != 0){ 23707090dd7Srsc iunlockput(dp); 23807090dd7Srsc ilock(ip); 239f9a06440SRuss Cox if(type == T_FILE && ip->type == T_FILE) 240f9a06440SRuss Cox return ip; 24107090dd7Srsc iunlockput(ip); 242eaea18cbSrsc return 0; 243eaea18cbSrsc } 244eaea18cbSrsc 245f9a06440SRuss Cox if((ip = ialloc(dp->dev, type)) == 0) 246f9a06440SRuss Cox panic("create: ialloc"); 247f9a06440SRuss Cox 24807090dd7Srsc ilock(ip); 249eaea18cbSrsc ip->major = major; 250eaea18cbSrsc ip->minor = minor; 251603deefcSrsc ip->nlink = 1; 252eaea18cbSrsc iupdate(ip); 253eaea18cbSrsc 254eaea18cbSrsc if(type == T_DIR){ // Create . and .. entries. 255eaea18cbSrsc dp->nlink++; // for ".." 256eaea18cbSrsc iupdate(dp); 257eaea18cbSrsc // No ip->nlink++ for ".": avoid cyclic ref count. 258eaea18cbSrsc if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) 259e79b1659Srsc panic("create dots"); 260eaea18cbSrsc } 261f3e87bc8Skolya 262f3685aa3Srsc if(dirlink(dp, name, ip->inum) < 0) 263f3685aa3Srsc panic("create: dirlink"); 264f3e87bc8Skolya 26507090dd7Srsc iunlockput(dp); 266*2e590463SRobert Morris 267eaea18cbSrsc return ip; 268eaea18cbSrsc } 269eaea18cbSrsc 2702685309fSrsc int 2712685309fSrsc sys_open(void) 2722685309fSrsc { 273f32f3638Srsc char *path; 274f32f3638Srsc int fd, omode; 275224f6598Srsc struct file *f; 276f32f3638Srsc struct inode *ip; 2772685309fSrsc 278224f6598Srsc if(argstr(0, &path) < 0 || argint(1, &omode) < 0) 2792685309fSrsc return -1; 280eaea18cbSrsc if(omode & O_CREATE){ 281*2e590463SRobert Morris begin_trans(); 282*2e590463SRobert Morris ip = create(path, T_FILE, 0, 0); 283*2e590463SRobert Morris commit_trans(); 284*2e590463SRobert Morris if(ip == 0) 285e2a620daSrsc return -1; 286eaea18cbSrsc } else { 28707090dd7Srsc if((ip = namei(path)) == 0) 288eaea18cbSrsc return -1; 28907090dd7Srsc ilock(ip); 290f3685aa3Srsc if(ip->type == T_DIR && omode != O_RDONLY){ 29107090dd7Srsc iunlockput(ip); 2922685309fSrsc return -1; 2932685309fSrsc } 294eaea18cbSrsc } 2952685309fSrsc 296eaea18cbSrsc if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ 297eaea18cbSrsc if(f) 298224f6598Srsc fileclose(f); 29907090dd7Srsc iunlockput(ip); 3002685309fSrsc return -1; 3012685309fSrsc } 30207090dd7Srsc iunlock(ip); 3032685309fSrsc 304eaea18cbSrsc f->type = FD_INODE; 30507090dd7Srsc f->ip = ip; 306eaea18cbSrsc f->off = 0; 307e79b1659Srsc f->readable = !(omode & O_WRONLY); 308e79b1659Srsc f->writable = (omode & O_WRONLY) || (omode & O_RDWR); 309224f6598Srsc return fd; 3102685309fSrsc } 3112685309fSrsc 3122685309fSrsc int 313f9a06440SRuss Cox sys_mkdir(void) 314f9a06440SRuss Cox { 315f9a06440SRuss Cox char *path; 316f9a06440SRuss Cox struct inode *ip; 317f9a06440SRuss Cox 318*2e590463SRobert Morris begin_trans(); 319*2e590463SRobert Morris if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0){ 320*2e590463SRobert Morris commit_trans(); 321f9a06440SRuss Cox return -1; 322*2e590463SRobert Morris } 323f9a06440SRuss Cox iunlockput(ip); 324*2e590463SRobert Morris commit_trans(); 325f9a06440SRuss Cox return 0; 326f9a06440SRuss Cox } 327f9a06440SRuss Cox 328f9a06440SRuss Cox int 3292685309fSrsc sys_mknod(void) 3302685309fSrsc { 331eaea18cbSrsc struct inode *ip; 332224f6598Srsc char *path; 333224f6598Srsc int len; 334aa6824abSrsc int major, minor; 3352685309fSrsc 336*2e590463SRobert Morris begin_trans(); 33707090dd7Srsc if((len=argstr(0, &path)) < 0 || 33807090dd7Srsc argint(1, &major) < 0 || 33907090dd7Srsc argint(2, &minor) < 0 || 340*2e590463SRobert Morris (ip = create(path, T_DEV, major, minor)) == 0){ 341*2e590463SRobert Morris commit_trans(); 3422685309fSrsc return -1; 343*2e590463SRobert Morris } 34407090dd7Srsc iunlockput(ip); 345*2e590463SRobert Morris commit_trans(); 346224f6598Srsc return 0; 3472685309fSrsc } 3482685309fSrsc 3492685309fSrsc int 3502685309fSrsc sys_chdir(void) 3512685309fSrsc { 352eaea18cbSrsc char *path; 3532685309fSrsc struct inode *ip; 3542685309fSrsc 35507090dd7Srsc if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) 3562685309fSrsc return -1; 35707090dd7Srsc ilock(ip); 3582685309fSrsc if(ip->type != T_DIR){ 35907090dd7Srsc iunlockput(ip); 3602685309fSrsc return -1; 3612685309fSrsc } 36207090dd7Srsc iunlock(ip); 36348755214SRuss Cox iput(proc->cwd); 36448755214SRuss Cox proc->cwd = ip; 3652685309fSrsc return 0; 3662685309fSrsc } 3672685309fSrsc 3682685309fSrsc int 3692685309fSrsc sys_exec(void) 3702685309fSrsc { 3714655d42eSRobert Morris char *path, *argv[MAXARG]; 372f32f3638Srsc int i; 373f32f3638Srsc uint uargv, uarg; 3742685309fSrsc 37540889627SFrans Kaashoek if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0){ 3762685309fSrsc return -1; 37740889627SFrans Kaashoek } 378eaea18cbSrsc memset(argv, 0, sizeof(argv)); 3792685309fSrsc for(i=0;; i++){ 380eaea18cbSrsc if(i >= NELEM(argv)) 3812685309fSrsc return -1; 38248755214SRuss Cox if(fetchint(proc, uargv+4*i, (int*)&uarg) < 0) 383f32f3638Srsc return -1; 384f32f3638Srsc if(uarg == 0){ 385f32f3638Srsc argv[i] = 0; 386f32f3638Srsc break; 3872685309fSrsc } 38848755214SRuss Cox if(fetchstr(proc, uarg, &argv[i]) < 0) 389f32f3638Srsc return -1; 390f32f3638Srsc } 391f32f3638Srsc return exec(path, argv); 392f32f3638Srsc } 393f32f3638Srsc 394eaea18cbSrsc int 395eaea18cbSrsc sys_pipe(void) 396eaea18cbSrsc { 397eaea18cbSrsc int *fd; 398eaea18cbSrsc struct file *rf, *wf; 399eaea18cbSrsc int fd0, fd1; 400eaea18cbSrsc 401eaea18cbSrsc if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) 402eaea18cbSrsc return -1; 4037834cca6Srsc if(pipealloc(&rf, &wf) < 0) 404eaea18cbSrsc return -1; 405eaea18cbSrsc fd0 = -1; 406eaea18cbSrsc if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ 407eaea18cbSrsc if(fd0 >= 0) 40848755214SRuss Cox proc->ofile[fd0] = 0; 409eaea18cbSrsc fileclose(rf); 410eaea18cbSrsc fileclose(wf); 411eaea18cbSrsc return -1; 412eaea18cbSrsc } 413eaea18cbSrsc fd[0] = fd0; 414eaea18cbSrsc fd[1] = fd1; 415eaea18cbSrsc return 0; 416eaea18cbSrsc } 417