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 } 124eaea18cbSrsc ip->nlink++; 125eaea18cbSrsc iupdate(ip); 12607090dd7Srsc iunlock(ip); 127eaea18cbSrsc 12807090dd7Srsc if((dp = nameiparent(new, name)) == 0) 12907090dd7Srsc goto bad; 13007090dd7Srsc ilock(dp); 131f3685aa3Srsc if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){ 132f3685aa3Srsc iunlockput(dp); 13307090dd7Srsc goto bad; 134f3685aa3Srsc } 13507090dd7Srsc iunlockput(dp); 13607090dd7Srsc iput(ip); 13707090dd7Srsc return 0; 13807090dd7Srsc 13907090dd7Srsc bad: 14007090dd7Srsc ilock(ip); 141eaea18cbSrsc ip->nlink--; 142eaea18cbSrsc iupdate(ip); 14307090dd7Srsc iunlockput(ip); 144eaea18cbSrsc return -1; 145eaea18cbSrsc } 146eaea18cbSrsc 147eaea18cbSrsc // Is the directory dp empty except for "." and ".." ? 148eaea18cbSrsc static int 149eaea18cbSrsc isdirempty(struct inode *dp) 150eaea18cbSrsc { 151eaea18cbSrsc int off; 152eaea18cbSrsc struct dirent de; 153eaea18cbSrsc 154eaea18cbSrsc for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){ 155eaea18cbSrsc if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 156eaea18cbSrsc panic("isdirempty: readi"); 157eaea18cbSrsc if(de.inum != 0) 158eaea18cbSrsc return 0; 159eaea18cbSrsc } 160eaea18cbSrsc return 1; 161eaea18cbSrsc } 162eaea18cbSrsc 1638d2e9a48Srsc //PAGEBREAK! 164eaea18cbSrsc int 165eaea18cbSrsc sys_unlink(void) 166eaea18cbSrsc { 167eaea18cbSrsc struct inode *ip, *dp; 168eaea18cbSrsc struct dirent de; 169eaea18cbSrsc char name[DIRSIZ], *path; 170eaea18cbSrsc uint off; 171eaea18cbSrsc 172eaea18cbSrsc if(argstr(0, &path) < 0) 173eaea18cbSrsc return -1; 17407090dd7Srsc if((dp = nameiparent(path, name)) == 0) 175eaea18cbSrsc return -1; 17607090dd7Srsc ilock(dp); 177eaea18cbSrsc 178eaea18cbSrsc // Cannot unlink "." or "..". 179eaea18cbSrsc if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0){ 18007090dd7Srsc iunlockput(dp); 181eaea18cbSrsc return -1; 182eaea18cbSrsc } 183eaea18cbSrsc 18407090dd7Srsc if((ip = dirlookup(dp, name, &off)) == 0){ 18507090dd7Srsc iunlockput(dp); 186eaea18cbSrsc return -1; 187eaea18cbSrsc } 18807090dd7Srsc ilock(ip); 189eaea18cbSrsc 190eaea18cbSrsc if(ip->nlink < 1) 191eaea18cbSrsc panic("unlink: nlink < 1"); 192eaea18cbSrsc if(ip->type == T_DIR && !isdirempty(ip)){ 19307090dd7Srsc iunlockput(ip); 19407090dd7Srsc iunlockput(dp); 195eaea18cbSrsc return -1; 196eaea18cbSrsc } 197eaea18cbSrsc 198eaea18cbSrsc memset(&de, 0, sizeof(de)); 199eaea18cbSrsc if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 200eaea18cbSrsc panic("unlink: writei"); 20115a26936Skolya if(ip->type == T_DIR){ 20215a26936Skolya dp->nlink--; 20315a26936Skolya iupdate(dp); 20415a26936Skolya } 20507090dd7Srsc iunlockput(dp); 206eaea18cbSrsc 207eaea18cbSrsc ip->nlink--; 208eaea18cbSrsc iupdate(ip); 20907090dd7Srsc iunlockput(ip); 210eaea18cbSrsc return 0; 211eaea18cbSrsc } 212eaea18cbSrsc 213eaea18cbSrsc static struct inode* 214f3685aa3Srsc create(char *path, short type, short major, short minor) 215eaea18cbSrsc { 216eaea18cbSrsc uint off; 217eaea18cbSrsc struct inode *ip, *dp; 218eaea18cbSrsc char name[DIRSIZ]; 219eaea18cbSrsc 22007090dd7Srsc if((dp = nameiparent(path, name)) == 0) 221eaea18cbSrsc return 0; 22207090dd7Srsc ilock(dp); 223eaea18cbSrsc 224f3685aa3Srsc if((ip = dirlookup(dp, name, &off)) != 0){ 22507090dd7Srsc iunlockput(dp); 22607090dd7Srsc ilock(ip); 227f9a06440SRuss Cox if(type == T_FILE && ip->type == T_FILE) 228f9a06440SRuss Cox return ip; 22907090dd7Srsc iunlockput(ip); 230eaea18cbSrsc return 0; 231eaea18cbSrsc } 232eaea18cbSrsc 233f9a06440SRuss Cox if((ip = ialloc(dp->dev, type)) == 0) 234f9a06440SRuss Cox panic("create: ialloc"); 235f9a06440SRuss Cox 23607090dd7Srsc ilock(ip); 237eaea18cbSrsc ip->major = major; 238eaea18cbSrsc ip->minor = minor; 239603deefcSrsc ip->nlink = 1; 240eaea18cbSrsc iupdate(ip); 241eaea18cbSrsc 242eaea18cbSrsc if(type == T_DIR){ // Create . and .. entries. 243eaea18cbSrsc dp->nlink++; // for ".." 244eaea18cbSrsc iupdate(dp); 245eaea18cbSrsc // No ip->nlink++ for ".": avoid cyclic ref count. 246eaea18cbSrsc if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) 247e79b1659Srsc panic("create dots"); 248eaea18cbSrsc } 249f3e87bc8Skolya 250f3685aa3Srsc if(dirlink(dp, name, ip->inum) < 0) 251f3685aa3Srsc panic("create: dirlink"); 252f3e87bc8Skolya 25307090dd7Srsc iunlockput(dp); 254eaea18cbSrsc return ip; 255eaea18cbSrsc } 256eaea18cbSrsc 2572685309fSrsc int 2582685309fSrsc sys_open(void) 2592685309fSrsc { 260f32f3638Srsc char *path; 261f32f3638Srsc int fd, omode; 262224f6598Srsc struct file *f; 263f32f3638Srsc struct inode *ip; 2642685309fSrsc 265224f6598Srsc if(argstr(0, &path) < 0 || argint(1, &omode) < 0) 2662685309fSrsc return -1; 267eaea18cbSrsc if(omode & O_CREATE){ 268f3685aa3Srsc if((ip = create(path, T_FILE, 0, 0)) == 0) 269e2a620daSrsc return -1; 270eaea18cbSrsc } else { 27107090dd7Srsc if((ip = namei(path)) == 0) 272eaea18cbSrsc return -1; 27307090dd7Srsc ilock(ip); 274f3685aa3Srsc if(ip->type == T_DIR && omode != O_RDONLY){ 27507090dd7Srsc iunlockput(ip); 2762685309fSrsc return -1; 2772685309fSrsc } 278eaea18cbSrsc } 2792685309fSrsc 280eaea18cbSrsc if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ 281eaea18cbSrsc if(f) 282224f6598Srsc fileclose(f); 28307090dd7Srsc iunlockput(ip); 2842685309fSrsc return -1; 2852685309fSrsc } 28607090dd7Srsc iunlock(ip); 2872685309fSrsc 288eaea18cbSrsc f->type = FD_INODE; 28907090dd7Srsc f->ip = ip; 290eaea18cbSrsc f->off = 0; 291e79b1659Srsc f->readable = !(omode & O_WRONLY); 292e79b1659Srsc f->writable = (omode & O_WRONLY) || (omode & O_RDWR); 293224f6598Srsc return fd; 2942685309fSrsc } 2952685309fSrsc 2962685309fSrsc int 297f9a06440SRuss Cox sys_mkdir(void) 298f9a06440SRuss Cox { 299f9a06440SRuss Cox char *path; 300f9a06440SRuss Cox struct inode *ip; 301f9a06440SRuss Cox 302f9a06440SRuss Cox if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0) 303f9a06440SRuss Cox return -1; 304f9a06440SRuss Cox iunlockput(ip); 305f9a06440SRuss Cox return 0; 306f9a06440SRuss Cox } 307f9a06440SRuss Cox 308f9a06440SRuss Cox int 3092685309fSrsc sys_mknod(void) 3102685309fSrsc { 311eaea18cbSrsc struct inode *ip; 312224f6598Srsc char *path; 313224f6598Srsc int len; 314aa6824abSrsc int major, minor; 3152685309fSrsc 31607090dd7Srsc if((len=argstr(0, &path)) < 0 || 31707090dd7Srsc argint(1, &major) < 0 || 31807090dd7Srsc argint(2, &minor) < 0 || 319f3685aa3Srsc (ip = create(path, T_DEV, major, minor)) == 0) 3202685309fSrsc return -1; 32107090dd7Srsc iunlockput(ip); 322224f6598Srsc return 0; 3232685309fSrsc } 3242685309fSrsc 3252685309fSrsc int 3262685309fSrsc sys_chdir(void) 3272685309fSrsc { 328eaea18cbSrsc char *path; 3292685309fSrsc struct inode *ip; 3302685309fSrsc 33107090dd7Srsc if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) 3322685309fSrsc return -1; 33307090dd7Srsc ilock(ip); 3342685309fSrsc if(ip->type != T_DIR){ 33507090dd7Srsc iunlockput(ip); 3362685309fSrsc return -1; 3372685309fSrsc } 33807090dd7Srsc iunlock(ip); 33948755214SRuss Cox iput(proc->cwd); 34048755214SRuss Cox proc->cwd = ip; 3412685309fSrsc return 0; 3422685309fSrsc } 3432685309fSrsc 3442685309fSrsc int 3452685309fSrsc sys_exec(void) 3462685309fSrsc { 347*4655d42eSRobert Morris char *path, *argv[MAXARG]; 348f32f3638Srsc int i; 349f32f3638Srsc uint uargv, uarg; 3502685309fSrsc 35140889627SFrans Kaashoek if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0) { 3522685309fSrsc return -1; 35340889627SFrans Kaashoek } 354eaea18cbSrsc memset(argv, 0, sizeof(argv)); 3552685309fSrsc for(i=0;; i++){ 356eaea18cbSrsc if(i >= NELEM(argv)) 3572685309fSrsc return -1; 35848755214SRuss Cox if(fetchint(proc, uargv+4*i, (int*)&uarg) < 0) 359f32f3638Srsc return -1; 360f32f3638Srsc if(uarg == 0){ 361f32f3638Srsc argv[i] = 0; 362f32f3638Srsc break; 3632685309fSrsc } 36448755214SRuss Cox if(fetchstr(proc, uarg, &argv[i]) < 0) 365f32f3638Srsc return -1; 366f32f3638Srsc } 367f32f3638Srsc return exec(path, argv); 368f32f3638Srsc } 369f32f3638Srsc 370eaea18cbSrsc int 371eaea18cbSrsc sys_pipe(void) 372eaea18cbSrsc { 373eaea18cbSrsc int *fd; 374eaea18cbSrsc struct file *rf, *wf; 375eaea18cbSrsc int fd0, fd1; 376eaea18cbSrsc 377eaea18cbSrsc if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) 378eaea18cbSrsc return -1; 3797834cca6Srsc if(pipealloc(&rf, &wf) < 0) 380eaea18cbSrsc return -1; 381eaea18cbSrsc fd0 = -1; 382eaea18cbSrsc if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ 383eaea18cbSrsc if(fd0 >= 0) 38448755214SRuss Cox proc->ofile[fd0] = 0; 385eaea18cbSrsc fileclose(rf); 386eaea18cbSrsc fileclose(wf); 387eaea18cbSrsc return -1; 388eaea18cbSrsc } 389eaea18cbSrsc fd[0] = fd0; 390eaea18cbSrsc fd[1] = fd1; 391eaea18cbSrsc return 0; 392eaea18cbSrsc } 393