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; 1195053dd6aSRobert Morris 1205053dd6aSRobert Morris begin_trans(); 1215053dd6aSRobert Morris 12207090dd7Srsc ilock(ip); 123eaea18cbSrsc if(ip->type == T_DIR){ 12407090dd7Srsc iunlockput(ip); 1255053dd6aSRobert Morris commit_trans(); 126eaea18cbSrsc return -1; 127eaea18cbSrsc } 1282e590463SRobert Morris 129eaea18cbSrsc ip->nlink++; 130eaea18cbSrsc iupdate(ip); 13107090dd7Srsc iunlock(ip); 132eaea18cbSrsc 13307090dd7Srsc if((dp = nameiparent(new, name)) == 0) 13407090dd7Srsc goto bad; 13507090dd7Srsc ilock(dp); 136f3685aa3Srsc if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){ 137f3685aa3Srsc iunlockput(dp); 13807090dd7Srsc goto bad; 139f3685aa3Srsc } 14007090dd7Srsc iunlockput(dp); 14107090dd7Srsc iput(ip); 1422e590463SRobert Morris 1432e590463SRobert Morris commit_trans(); 1442e590463SRobert Morris 14507090dd7Srsc return 0; 14607090dd7Srsc 14707090dd7Srsc bad: 14807090dd7Srsc ilock(ip); 149eaea18cbSrsc ip->nlink--; 150eaea18cbSrsc iupdate(ip); 15107090dd7Srsc iunlockput(ip); 1522e590463SRobert Morris commit_trans(); 153eaea18cbSrsc return -1; 154eaea18cbSrsc } 155eaea18cbSrsc 156eaea18cbSrsc // Is the directory dp empty except for "." and ".." ? 157eaea18cbSrsc static int 158eaea18cbSrsc isdirempty(struct inode *dp) 159eaea18cbSrsc { 160eaea18cbSrsc int off; 161eaea18cbSrsc struct dirent de; 162eaea18cbSrsc 163eaea18cbSrsc for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){ 164eaea18cbSrsc if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 165eaea18cbSrsc panic("isdirempty: readi"); 166eaea18cbSrsc if(de.inum != 0) 167eaea18cbSrsc return 0; 168eaea18cbSrsc } 169eaea18cbSrsc return 1; 170eaea18cbSrsc } 171eaea18cbSrsc 1728d2e9a48Srsc //PAGEBREAK! 173eaea18cbSrsc int 174eaea18cbSrsc sys_unlink(void) 175eaea18cbSrsc { 176eaea18cbSrsc struct inode *ip, *dp; 177eaea18cbSrsc struct dirent de; 178eaea18cbSrsc char name[DIRSIZ], *path; 179eaea18cbSrsc uint off; 180eaea18cbSrsc 181eaea18cbSrsc if(argstr(0, &path) < 0) 182eaea18cbSrsc return -1; 18307090dd7Srsc if((dp = nameiparent(path, name)) == 0) 184eaea18cbSrsc return -1; 1855053dd6aSRobert Morris 1865053dd6aSRobert Morris begin_trans(); 1875053dd6aSRobert Morris 18807090dd7Srsc ilock(dp); 189eaea18cbSrsc 190eaea18cbSrsc // Cannot unlink "." or "..". 191*4e015d81SAustin Clements if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0) 192*4e015d81SAustin Clements goto bad; 193eaea18cbSrsc 194*4e015d81SAustin Clements if((ip = dirlookup(dp, name, &off)) == 0) 195*4e015d81SAustin Clements goto bad; 19607090dd7Srsc ilock(ip); 197eaea18cbSrsc 198eaea18cbSrsc if(ip->nlink < 1) 199eaea18cbSrsc panic("unlink: nlink < 1"); 200eaea18cbSrsc if(ip->type == T_DIR && !isdirempty(ip)){ 20107090dd7Srsc iunlockput(ip); 202*4e015d81SAustin Clements goto bad; 203eaea18cbSrsc } 204eaea18cbSrsc 205eaea18cbSrsc memset(&de, 0, sizeof(de)); 206eaea18cbSrsc if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 207eaea18cbSrsc panic("unlink: writei"); 20815a26936Skolya if(ip->type == T_DIR){ 20915a26936Skolya dp->nlink--; 21015a26936Skolya iupdate(dp); 21115a26936Skolya } 21207090dd7Srsc iunlockput(dp); 213eaea18cbSrsc 214eaea18cbSrsc ip->nlink--; 215eaea18cbSrsc iupdate(ip); 21607090dd7Srsc iunlockput(ip); 2172e590463SRobert Morris 2182e590463SRobert Morris commit_trans(); 2192e590463SRobert Morris 220eaea18cbSrsc return 0; 221*4e015d81SAustin Clements 222*4e015d81SAustin Clements bad: 223*4e015d81SAustin Clements iunlockput(dp); 224*4e015d81SAustin Clements commit_trans(); 225*4e015d81SAustin Clements return -1; 226eaea18cbSrsc } 227eaea18cbSrsc 228eaea18cbSrsc static struct inode* 229f3685aa3Srsc create(char *path, short type, short major, short minor) 230eaea18cbSrsc { 231eaea18cbSrsc uint off; 232eaea18cbSrsc struct inode *ip, *dp; 233eaea18cbSrsc char name[DIRSIZ]; 234eaea18cbSrsc 23507090dd7Srsc if((dp = nameiparent(path, name)) == 0) 236eaea18cbSrsc return 0; 23707090dd7Srsc ilock(dp); 238eaea18cbSrsc 239f3685aa3Srsc if((ip = dirlookup(dp, name, &off)) != 0){ 24007090dd7Srsc iunlockput(dp); 24107090dd7Srsc ilock(ip); 242f9a06440SRuss Cox if(type == T_FILE && ip->type == T_FILE) 243f9a06440SRuss Cox return ip; 24407090dd7Srsc iunlockput(ip); 245eaea18cbSrsc return 0; 246eaea18cbSrsc } 247eaea18cbSrsc 248f9a06440SRuss Cox if((ip = ialloc(dp->dev, type)) == 0) 249f9a06440SRuss Cox panic("create: ialloc"); 250f9a06440SRuss Cox 25107090dd7Srsc ilock(ip); 252eaea18cbSrsc ip->major = major; 253eaea18cbSrsc ip->minor = minor; 254603deefcSrsc ip->nlink = 1; 255eaea18cbSrsc iupdate(ip); 256eaea18cbSrsc 257eaea18cbSrsc if(type == T_DIR){ // Create . and .. entries. 258eaea18cbSrsc dp->nlink++; // for ".." 259eaea18cbSrsc iupdate(dp); 260eaea18cbSrsc // No ip->nlink++ for ".": avoid cyclic ref count. 261eaea18cbSrsc if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) 262e79b1659Srsc panic("create dots"); 263eaea18cbSrsc } 264f3e87bc8Skolya 265f3685aa3Srsc if(dirlink(dp, name, ip->inum) < 0) 266f3685aa3Srsc panic("create: dirlink"); 267f3e87bc8Skolya 26807090dd7Srsc iunlockput(dp); 2692e590463SRobert Morris 270eaea18cbSrsc return ip; 271eaea18cbSrsc } 272eaea18cbSrsc 2732685309fSrsc int 2742685309fSrsc sys_open(void) 2752685309fSrsc { 276f32f3638Srsc char *path; 277f32f3638Srsc int fd, omode; 278224f6598Srsc struct file *f; 279f32f3638Srsc struct inode *ip; 2802685309fSrsc 281224f6598Srsc if(argstr(0, &path) < 0 || argint(1, &omode) < 0) 2822685309fSrsc return -1; 283eaea18cbSrsc if(omode & O_CREATE){ 2842e590463SRobert Morris begin_trans(); 2852e590463SRobert Morris ip = create(path, T_FILE, 0, 0); 2862e590463SRobert Morris commit_trans(); 2872e590463SRobert Morris if(ip == 0) 288e2a620daSrsc return -1; 289eaea18cbSrsc } else { 29007090dd7Srsc if((ip = namei(path)) == 0) 291eaea18cbSrsc return -1; 29207090dd7Srsc ilock(ip); 293f3685aa3Srsc if(ip->type == T_DIR && omode != O_RDONLY){ 29407090dd7Srsc iunlockput(ip); 2952685309fSrsc return -1; 2962685309fSrsc } 297eaea18cbSrsc } 2982685309fSrsc 299eaea18cbSrsc if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ 300eaea18cbSrsc if(f) 301224f6598Srsc fileclose(f); 30207090dd7Srsc iunlockput(ip); 3032685309fSrsc return -1; 3042685309fSrsc } 30507090dd7Srsc iunlock(ip); 3062685309fSrsc 307eaea18cbSrsc f->type = FD_INODE; 30807090dd7Srsc f->ip = ip; 309eaea18cbSrsc f->off = 0; 310e79b1659Srsc f->readable = !(omode & O_WRONLY); 311e79b1659Srsc f->writable = (omode & O_WRONLY) || (omode & O_RDWR); 312224f6598Srsc return fd; 3132685309fSrsc } 3142685309fSrsc 3152685309fSrsc int 316f9a06440SRuss Cox sys_mkdir(void) 317f9a06440SRuss Cox { 318f9a06440SRuss Cox char *path; 319f9a06440SRuss Cox struct inode *ip; 320f9a06440SRuss Cox 3212e590463SRobert Morris begin_trans(); 3222e590463SRobert Morris if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0){ 3232e590463SRobert Morris commit_trans(); 324f9a06440SRuss Cox return -1; 3252e590463SRobert Morris } 326f9a06440SRuss Cox iunlockput(ip); 3272e590463SRobert Morris commit_trans(); 328f9a06440SRuss Cox return 0; 329f9a06440SRuss Cox } 330f9a06440SRuss Cox 331f9a06440SRuss Cox int 3322685309fSrsc sys_mknod(void) 3332685309fSrsc { 334eaea18cbSrsc struct inode *ip; 335224f6598Srsc char *path; 336224f6598Srsc int len; 337aa6824abSrsc int major, minor; 3382685309fSrsc 3392e590463SRobert Morris begin_trans(); 34007090dd7Srsc if((len=argstr(0, &path)) < 0 || 34107090dd7Srsc argint(1, &major) < 0 || 34207090dd7Srsc argint(2, &minor) < 0 || 3432e590463SRobert Morris (ip = create(path, T_DEV, major, minor)) == 0){ 3442e590463SRobert Morris commit_trans(); 3452685309fSrsc return -1; 3462e590463SRobert Morris } 34707090dd7Srsc iunlockput(ip); 3482e590463SRobert Morris commit_trans(); 349224f6598Srsc return 0; 3502685309fSrsc } 3512685309fSrsc 3522685309fSrsc int 3532685309fSrsc sys_chdir(void) 3542685309fSrsc { 355eaea18cbSrsc char *path; 3562685309fSrsc struct inode *ip; 3572685309fSrsc 35807090dd7Srsc if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) 3592685309fSrsc return -1; 36007090dd7Srsc ilock(ip); 3612685309fSrsc if(ip->type != T_DIR){ 36207090dd7Srsc iunlockput(ip); 3632685309fSrsc return -1; 3642685309fSrsc } 36507090dd7Srsc iunlock(ip); 36648755214SRuss Cox iput(proc->cwd); 36748755214SRuss Cox proc->cwd = ip; 3682685309fSrsc return 0; 3692685309fSrsc } 3702685309fSrsc 3712685309fSrsc int 3722685309fSrsc sys_exec(void) 3732685309fSrsc { 3744655d42eSRobert Morris char *path, *argv[MAXARG]; 375f32f3638Srsc int i; 376f32f3638Srsc uint uargv, uarg; 3772685309fSrsc 37840889627SFrans Kaashoek if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0){ 3792685309fSrsc return -1; 38040889627SFrans Kaashoek } 381eaea18cbSrsc memset(argv, 0, sizeof(argv)); 3822685309fSrsc for(i=0;; i++){ 383eaea18cbSrsc if(i >= NELEM(argv)) 3842685309fSrsc return -1; 38548755214SRuss Cox if(fetchint(proc, uargv+4*i, (int*)&uarg) < 0) 386f32f3638Srsc return -1; 387f32f3638Srsc if(uarg == 0){ 388f32f3638Srsc argv[i] = 0; 389f32f3638Srsc break; 3902685309fSrsc } 39148755214SRuss Cox if(fetchstr(proc, uarg, &argv[i]) < 0) 392f32f3638Srsc return -1; 393f32f3638Srsc } 394f32f3638Srsc return exec(path, argv); 395f32f3638Srsc } 396f32f3638Srsc 397eaea18cbSrsc int 398eaea18cbSrsc sys_pipe(void) 399eaea18cbSrsc { 400eaea18cbSrsc int *fd; 401eaea18cbSrsc struct file *rf, *wf; 402eaea18cbSrsc int fd0, fd1; 403eaea18cbSrsc 404eaea18cbSrsc if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) 405eaea18cbSrsc return -1; 4067834cca6Srsc if(pipealloc(&rf, &wf) < 0) 407eaea18cbSrsc return -1; 408eaea18cbSrsc fd0 = -1; 409eaea18cbSrsc if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ 410eaea18cbSrsc if(fd0 >= 0) 41148755214SRuss Cox proc->ofile[fd0] = 0; 412eaea18cbSrsc fileclose(rf); 413eaea18cbSrsc fileclose(wf); 414eaea18cbSrsc return -1; 415eaea18cbSrsc } 416eaea18cbSrsc fd[0] = fd0; 417eaea18cbSrsc fd[1] = fd1; 418eaea18cbSrsc return 0; 419eaea18cbSrsc } 420