12685309fSrsc #include "types.h" 22685309fSrsc #include "stat.h" 32685309fSrsc #include "param.h" 42685309fSrsc #include "mmu.h" 52685309fSrsc #include "proc.h" 62685309fSrsc #include "defs.h" 72685309fSrsc #include "x86.h" 82685309fSrsc #include "traps.h" 92685309fSrsc #include "syscall.h" 102685309fSrsc #include "spinlock.h" 112685309fSrsc #include "buf.h" 122685309fSrsc #include "fs.h" 132685309fSrsc #include "fsvar.h" 149936bffaSrsc #include "file.h" 152685309fSrsc #include "fcntl.h" 162685309fSrsc 17224f6598Srsc // Fetch the nth word-sized system call argument as a file descriptor 18224f6598Srsc // and return both the descriptor and the corresponding struct file. 19224f6598Srsc static int 20224f6598Srsc argfd(int argno, int *pfd, struct file **pf) 21224f6598Srsc { 22224f6598Srsc int fd; 23224f6598Srsc struct file *f; 24224f6598Srsc 25224f6598Srsc if(argint(argno, &fd) < 0) 26224f6598Srsc return -1; 279583b476Srsc if(fd < 0 || fd >= NOFILE || (f=cp->ofile[fd]) == 0) 28224f6598Srsc return -1; 29224f6598Srsc if(pfd) 30224f6598Srsc *pfd = fd; 31224f6598Srsc if(pf) 32224f6598Srsc *pf = f; 33224f6598Srsc return 0; 34224f6598Srsc } 35224f6598Srsc 36224f6598Srsc // Allocate a file descriptor for the given file. 37224f6598Srsc // Takes over file reference from caller on success. 38224f6598Srsc static int 39224f6598Srsc fdalloc(struct file *f) 40224f6598Srsc { 41224f6598Srsc int fd; 429583b476Srsc 43224f6598Srsc for(fd = 0; fd < NOFILE; fd++){ 449583b476Srsc if(cp->ofile[fd] == 0){ 459583b476Srsc cp->ofile[fd] = f; 46224f6598Srsc return fd; 47224f6598Srsc } 48224f6598Srsc } 49224f6598Srsc return -1; 50224f6598Srsc } 51224f6598Srsc 522685309fSrsc int 53eaea18cbSrsc sys_read(void) 542685309fSrsc { 55eaea18cbSrsc struct file *f; 56eaea18cbSrsc int n; 57eaea18cbSrsc char *cp; 582685309fSrsc 59eaea18cbSrsc if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &cp, n) < 0) 602685309fSrsc return -1; 61eaea18cbSrsc return fileread(f, cp, n); 622685309fSrsc } 632685309fSrsc 642685309fSrsc int 652685309fSrsc sys_write(void) 662685309fSrsc { 67224f6598Srsc struct file *f; 68224f6598Srsc int n; 69224f6598Srsc char *cp; 702685309fSrsc 71224f6598Srsc if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &cp, n) < 0) 722685309fSrsc return -1; 73224f6598Srsc return filewrite(f, cp, n); 742685309fSrsc } 752685309fSrsc 762685309fSrsc int 77eaea18cbSrsc sys_fstat(void) 782685309fSrsc { 79224f6598Srsc struct file *f; 80eaea18cbSrsc struct stat *st; 812685309fSrsc 82eaea18cbSrsc if(argfd(0, 0, &f) < 0 || argptr(1, (void*)&st, sizeof(*st)) < 0) 832685309fSrsc return -1; 84eaea18cbSrsc return filestat(f, st); 852685309fSrsc } 862685309fSrsc 872685309fSrsc int 882685309fSrsc sys_close(void) 892685309fSrsc { 902685309fSrsc int fd; 91224f6598Srsc struct file *f; 922685309fSrsc 93224f6598Srsc if(argfd(0, &fd, &f) < 0) 942685309fSrsc return -1; 95b6095304Srsc cp->ofile[fd] = 0; 96224f6598Srsc fileclose(f); 972685309fSrsc return 0; 982685309fSrsc } 992685309fSrsc 100eaea18cbSrsc // Create the path new as a link to the same inode as old. 101eaea18cbSrsc int 102eaea18cbSrsc sys_link(void) 103eaea18cbSrsc { 104eaea18cbSrsc char name[DIRSIZ], *new, *old; 105eaea18cbSrsc struct inode *dp, *ip; 106eaea18cbSrsc 107eaea18cbSrsc if(argstr(0, &old) < 0 || argstr(1, &new) < 0) 108eaea18cbSrsc return -1; 10907090dd7Srsc if((ip = namei(old)) == 0) 110eaea18cbSrsc return -1; 11107090dd7Srsc ilock(ip); 112eaea18cbSrsc if(ip->type == T_DIR){ 11307090dd7Srsc iunlockput(ip); 114eaea18cbSrsc return -1; 115eaea18cbSrsc } 116eaea18cbSrsc ip->nlink++; 117eaea18cbSrsc iupdate(ip); 11807090dd7Srsc iunlock(ip); 119eaea18cbSrsc 12007090dd7Srsc if((dp = nameiparent(new, name)) == 0) 12107090dd7Srsc goto bad; 12207090dd7Srsc ilock(dp); 12307090dd7Srsc if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0) 12407090dd7Srsc goto bad; 12507090dd7Srsc iunlockput(dp); 12607090dd7Srsc iput(ip); 12707090dd7Srsc return 0; 12807090dd7Srsc 12907090dd7Srsc bad: 130eaea18cbSrsc if(dp) 13107090dd7Srsc iunlockput(dp); 13207090dd7Srsc ilock(ip); 133eaea18cbSrsc ip->nlink--; 134eaea18cbSrsc iupdate(ip); 13507090dd7Srsc iunlockput(ip); 136eaea18cbSrsc return -1; 137eaea18cbSrsc } 138eaea18cbSrsc 139eaea18cbSrsc // Is the directory dp empty except for "." and ".." ? 140eaea18cbSrsc static int 141eaea18cbSrsc isdirempty(struct inode *dp) 142eaea18cbSrsc { 143eaea18cbSrsc int off; 144eaea18cbSrsc struct dirent de; 145eaea18cbSrsc 146eaea18cbSrsc for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){ 147eaea18cbSrsc if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 148eaea18cbSrsc panic("isdirempty: readi"); 149eaea18cbSrsc if(de.inum != 0) 150eaea18cbSrsc return 0; 151eaea18cbSrsc } 152eaea18cbSrsc return 1; 153eaea18cbSrsc } 154eaea18cbSrsc 155eaea18cbSrsc int 156eaea18cbSrsc sys_unlink(void) 157eaea18cbSrsc { 158eaea18cbSrsc struct inode *ip, *dp; 159eaea18cbSrsc struct dirent de; 160eaea18cbSrsc char name[DIRSIZ], *path; 161eaea18cbSrsc uint off; 162eaea18cbSrsc 163eaea18cbSrsc if(argstr(0, &path) < 0) 164eaea18cbSrsc return -1; 16507090dd7Srsc if((dp = nameiparent(path, name)) == 0) 166eaea18cbSrsc return -1; 16707090dd7Srsc ilock(dp); 168eaea18cbSrsc 169eaea18cbSrsc // Cannot unlink "." or "..". 170eaea18cbSrsc if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0){ 17107090dd7Srsc iunlockput(dp); 172eaea18cbSrsc return -1; 173eaea18cbSrsc } 174eaea18cbSrsc 17507090dd7Srsc if((ip = dirlookup(dp, name, &off)) == 0){ 17607090dd7Srsc iunlockput(dp); 177eaea18cbSrsc return -1; 178eaea18cbSrsc } 17907090dd7Srsc ilock(ip); 180eaea18cbSrsc 181eaea18cbSrsc if(ip->nlink < 1) 182eaea18cbSrsc panic("unlink: nlink < 1"); 183eaea18cbSrsc if(ip->type == T_DIR && !isdirempty(ip)){ 18407090dd7Srsc iunlockput(ip); 18507090dd7Srsc iunlockput(dp); 186eaea18cbSrsc return -1; 187eaea18cbSrsc } 188eaea18cbSrsc 189eaea18cbSrsc memset(&de, 0, sizeof(de)); 190eaea18cbSrsc if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) 191eaea18cbSrsc panic("unlink: writei"); 19207090dd7Srsc iunlockput(dp); 193eaea18cbSrsc 194eaea18cbSrsc ip->nlink--; 195eaea18cbSrsc iupdate(ip); 19607090dd7Srsc iunlockput(ip); 197eaea18cbSrsc return 0; 198eaea18cbSrsc } 199eaea18cbSrsc 200eaea18cbSrsc static struct inode* 201eaea18cbSrsc mkpath(char *path, int canexist, short type, short major, short minor) 202eaea18cbSrsc { 203eaea18cbSrsc uint off; 204eaea18cbSrsc struct inode *ip, *dp; 205eaea18cbSrsc char name[DIRSIZ]; 206eaea18cbSrsc 20707090dd7Srsc if((dp = nameiparent(path, name)) == 0) 208eaea18cbSrsc return 0; 20907090dd7Srsc ilock(dp); 210eaea18cbSrsc 21107090dd7Srsc if(canexist && (ip = dirlookup(dp, name, &off)) != 0){ 21207090dd7Srsc iunlockput(dp); 21307090dd7Srsc ilock(ip); 214eaea18cbSrsc if(ip->type != type || ip->major != major || ip->minor != minor){ 21507090dd7Srsc iunlockput(ip); 216eaea18cbSrsc return 0; 217eaea18cbSrsc } 218eaea18cbSrsc return ip; 219eaea18cbSrsc } 220eaea18cbSrsc 22107090dd7Srsc if((ip = ialloc(dp->dev, type)) == 0){ 22207090dd7Srsc iunlockput(dp); 223eaea18cbSrsc return 0; 224eaea18cbSrsc } 22507090dd7Srsc ilock(ip); 226eaea18cbSrsc ip->major = major; 227eaea18cbSrsc ip->minor = minor; 228eaea18cbSrsc ip->size = 0; 229eaea18cbSrsc ip->nlink = 1; 230eaea18cbSrsc iupdate(ip); 231eaea18cbSrsc 232eaea18cbSrsc if(dirlink(dp, name, ip->inum) < 0){ 233eaea18cbSrsc ip->nlink = 0; 23407090dd7Srsc iunlockput(ip); 23507090dd7Srsc iunlockput(dp); 236eaea18cbSrsc return 0; 237eaea18cbSrsc } 238eaea18cbSrsc 239eaea18cbSrsc if(type == T_DIR){ // Create . and .. entries. 240eaea18cbSrsc dp->nlink++; // for ".." 241eaea18cbSrsc iupdate(dp); 242eaea18cbSrsc // No ip->nlink++ for ".": avoid cyclic ref count. 243eaea18cbSrsc if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) 244eaea18cbSrsc panic("mkpath dots"); 245eaea18cbSrsc } 24607090dd7Srsc iunlockput(dp); 247eaea18cbSrsc return ip; 248eaea18cbSrsc } 249eaea18cbSrsc 2502685309fSrsc int 2512685309fSrsc sys_open(void) 2522685309fSrsc { 253f32f3638Srsc char *path; 254f32f3638Srsc int fd, omode; 255224f6598Srsc struct file *f; 256f32f3638Srsc struct inode *ip; 2572685309fSrsc 258224f6598Srsc if(argstr(0, &path) < 0 || argint(1, &omode) < 0) 2592685309fSrsc return -1; 2602685309fSrsc 261eaea18cbSrsc if(omode & O_CREATE){ 262eaea18cbSrsc if((ip = mkpath(path, 1, T_FILE, 0, 0)) == 0) 263e2a620daSrsc return -1; 264eaea18cbSrsc }else{ 26507090dd7Srsc if((ip = namei(path)) == 0) 266eaea18cbSrsc return -1; 26707090dd7Srsc ilock(ip); 268f32f3638Srsc if(ip->type == T_DIR && (omode & (O_RDWR|O_WRONLY))){ 26907090dd7Srsc iunlockput(ip); 2702685309fSrsc return -1; 2712685309fSrsc } 272eaea18cbSrsc } 2732685309fSrsc 274eaea18cbSrsc if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ 275eaea18cbSrsc if(f) 276224f6598Srsc fileclose(f); 27707090dd7Srsc iunlockput(ip); 2782685309fSrsc return -1; 2792685309fSrsc } 28007090dd7Srsc iunlock(ip); 2812685309fSrsc 282eaea18cbSrsc f->type = FD_INODE; 28307090dd7Srsc f->ip = ip; 284eaea18cbSrsc f->off = 0; 285224f6598Srsc if(omode & O_RDWR) { 286224f6598Srsc f->readable = 1; 287224f6598Srsc f->writable = 1; 288224f6598Srsc } else if(omode & O_WRONLY) { 289224f6598Srsc f->readable = 0; 290224f6598Srsc f->writable = 1; 2912685309fSrsc } else { 292224f6598Srsc f->readable = 1; 293224f6598Srsc f->writable = 0; 2942685309fSrsc } 2952685309fSrsc 296224f6598Srsc return fd; 2972685309fSrsc } 2982685309fSrsc 2992685309fSrsc int 3002685309fSrsc sys_mknod(void) 3012685309fSrsc { 302eaea18cbSrsc struct inode *ip; 303224f6598Srsc char *path; 304224f6598Srsc int len; 305*aa6824abSrsc int major, minor; 3062685309fSrsc 30707090dd7Srsc if((len=argstr(0, &path)) < 0 || 30807090dd7Srsc argint(1, &major) < 0 || 30907090dd7Srsc argint(2, &minor) < 0 || 31007090dd7Srsc (ip = mkpath(path, 0, T_DEV, major, minor)) == 0) 3112685309fSrsc return -1; 31207090dd7Srsc iunlockput(ip); 313224f6598Srsc return 0; 3142685309fSrsc } 3152685309fSrsc 3162685309fSrsc int 3172685309fSrsc sys_mkdir(void) 3182685309fSrsc { 319f32f3638Srsc char *path; 320eaea18cbSrsc struct inode *ip; 3212685309fSrsc 322eaea18cbSrsc if(argstr(0, &path) < 0 || (ip = mkpath(path, 0, T_DIR, 0, 0)) == 0) 3232685309fSrsc return -1; 32407090dd7Srsc iunlockput(ip); 325eaea18cbSrsc return 0; 3262685309fSrsc } 3272685309fSrsc 3282685309fSrsc int 3292685309fSrsc sys_chdir(void) 3302685309fSrsc { 331eaea18cbSrsc char *path; 3322685309fSrsc struct inode *ip; 3332685309fSrsc 33407090dd7Srsc if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) 3352685309fSrsc return -1; 33607090dd7Srsc ilock(ip); 3372685309fSrsc if(ip->type != T_DIR) { 33807090dd7Srsc iunlockput(ip); 3392685309fSrsc return -1; 3402685309fSrsc } 34107090dd7Srsc iunlock(ip); 342eaea18cbSrsc iput(cp->cwd); 34307090dd7Srsc cp->cwd = ip; 3442685309fSrsc return 0; 3452685309fSrsc } 3462685309fSrsc 3472685309fSrsc int 3482685309fSrsc sys_dup(void) 3492685309fSrsc { 350224f6598Srsc struct file *f; 351224f6598Srsc int fd; 3522685309fSrsc 353224f6598Srsc if(argfd(0, 0, &f) < 0) 3542685309fSrsc return -1; 355224f6598Srsc if((fd=fdalloc(f)) < 0) 3562685309fSrsc return -1; 357224f6598Srsc fileincref(f); 358224f6598Srsc return fd; 3592685309fSrsc } 3602685309fSrsc 3612685309fSrsc int 3622685309fSrsc sys_exec(void) 3632685309fSrsc { 364eaea18cbSrsc char *path, *argv[20]; 365f32f3638Srsc int i; 366f32f3638Srsc uint uargv, uarg; 3672685309fSrsc 368f32f3638Srsc if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0) 3692685309fSrsc return -1; 370eaea18cbSrsc memset(argv, 0, sizeof(argv)); 3712685309fSrsc for(i=0;; i++){ 372eaea18cbSrsc if(i >= NELEM(argv)) 3732685309fSrsc return -1; 374f32f3638Srsc if(fetchint(cp, uargv+4*i, (int*)&uarg) < 0) 375f32f3638Srsc return -1; 376f32f3638Srsc if(uarg == 0){ 377f32f3638Srsc argv[i] = 0; 378f32f3638Srsc break; 3792685309fSrsc } 380f32f3638Srsc if(fetchstr(cp, uarg, &argv[i]) < 0) 381f32f3638Srsc return -1; 382f32f3638Srsc } 383f32f3638Srsc return exec(path, argv); 384f32f3638Srsc } 385f32f3638Srsc 386eaea18cbSrsc int 387eaea18cbSrsc sys_pipe(void) 388eaea18cbSrsc { 389eaea18cbSrsc int *fd; 390eaea18cbSrsc struct file *rf, *wf; 391eaea18cbSrsc int fd0, fd1; 392eaea18cbSrsc 393eaea18cbSrsc if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) 394eaea18cbSrsc return -1; 395eaea18cbSrsc if(pipe_alloc(&rf, &wf) < 0) 396eaea18cbSrsc return -1; 397eaea18cbSrsc fd0 = -1; 398eaea18cbSrsc if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ 399eaea18cbSrsc if(fd0 >= 0) 400eaea18cbSrsc cp->ofile[fd0] = 0; 401eaea18cbSrsc fileclose(rf); 402eaea18cbSrsc fileclose(wf); 403eaea18cbSrsc return -1; 404eaea18cbSrsc } 405eaea18cbSrsc fd[0] = fd0; 406eaea18cbSrsc fd[1] = fd1; 407eaea18cbSrsc return 0; 408eaea18cbSrsc } 409