ref: a50be99567d1b6018a0a1f019a51c0bc7a0f11ff
dir: /kern/devfs-posix.c/
#include "u.h" #include <sys/types.h> #include <sys/stat.h> #include <dirent.h> #include <fcntl.h> #include <errno.h> #include <stdio.h> /* for remove, rename */ #include <limits.h> #ifndef NAME_MAX # define NAME_MAX 256 #endif #include "lib.h" #include "dat.h" #include "fns.h" #include "error.h" typedef struct Ufsinfo Ufsinfo; struct Ufsinfo { int mode; int fd; int uid; int gid; DIR* dir; vlong offset; QLock oq; char* path; char nextname[NAME_MAX]; }; static Qid fsqid(struct stat *); static char* catpath(char*, char*); static ulong fsdirread(Chan*, uchar*, int, ulong); static int fsomode(int); static char* lastelem(char *s) { char *t; if((t = strrchr(s, '/')) == nil) return s; if(t[1] == 0) return t; return t+1; } static Chan* fsattach(char *spec) { Chan *c; struct stat stbuf; static int devno; Ufsinfo *uif; c = devattach('U', spec); uif = mallocz(sizeof(Ufsinfo), 1); uif->mode = stbuf.st_mode; uif->uid = stbuf.st_uid; uif->gid = stbuf.st_gid; uif->path = strdup("/"); c->aux = uif; c->dev = devno++; c->qid.type = QTDIR; /*print("fsattach %s\n", chanpath(c));*/ return c; } static Chan* fsclone(Chan *c, Chan *nc) { Ufsinfo *uif; uif = mallocz(sizeof(Ufsinfo), 1); *uif = *(Ufsinfo*)c->aux; uif->path = strdup(uif->path); nc->aux = uif; return nc; } static int fswalk1(Chan *c, char *name) { struct stat stbuf; Ufsinfo *uif; char *path; /*print("** fs walk '%s' -> %s\n", path, name); */ uif = c->aux; path = catpath(uif->path, name); if(stat(path, &stbuf) < 0){ free(path); return 0; } free(uif->path); uif->path = path; uif->mode = stbuf.st_mode; uif->uid = stbuf.st_uid; uif->gid = stbuf.st_gid; c->qid = fsqid(&stbuf); return 1; } static Walkqid* fswalk(Chan *c, Chan *nc, char **name, int nname) { int i; Walkqid *wq; if(nc != nil) panic("fswalk: nc != nil"); wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid)); nc = devclone(c); fsclone(c, nc); wq->clone = nc; for(i=0; i<nname; i++){ if(fswalk1(nc, name[i]) == 0) break; wq->qid[i] = nc->qid; } if(i != nname){ cclose(nc); wq->clone = nil; } wq->nqid = i; return wq; } static int fsstat(Chan *c, uchar *buf, int n) { Dir d; struct stat stbuf; Ufsinfo *uif; if(n < BIT16SZ) error(Eshortstat); uif = c->aux; if(stat(uif->path, &stbuf) < 0) error(strerror(errno)); d.name = lastelem(uif->path); d.uid = eve; d.gid = eve; d.muid = eve; d.qid = c->qid; d.mode = (c->qid.type<<24)|(stbuf.st_mode&0777); d.atime = stbuf.st_atime; d.mtime = stbuf.st_mtime; d.length = stbuf.st_size; d.type = 'U'; d.dev = c->dev; return convD2M(&d, buf, n); } static Chan* fsopen(Chan *c, int mode) { int m, isdir; Ufsinfo *uif; /*print("fsopen %s\n", chanpath(c));*/ m = mode & (OTRUNC|3); switch(m) { case 0: break; case 1: case 1|16: break; case 2: case 0|16: case 2|16: break; case 3: break; default: error(Ebadarg); } isdir = c->qid.type & QTDIR; if(isdir && mode != OREAD) error(Eperm); m = fsomode(m & 3); c->mode = openmode(mode); uif = c->aux; if(isdir) { uif->dir = opendir(uif->path); if(uif->dir == 0) error(strerror(errno)); } else { if(mode & OTRUNC) m |= O_TRUNC; uif->fd = open(uif->path, m, 0666); if(uif->fd < 0) error(strerror(errno)); } uif->offset = 0; c->offset = 0; c->flag |= COPEN; return c; } static Chan* fscreate(Chan *c, char *name, int mode, ulong perm) { int fd, m; char *path; struct stat stbuf; Ufsinfo *uif; m = fsomode(mode&3); uif = c->aux; path = catpath(uif->path, name); if(waserror()){ free(path); nexterror(); } if(perm & DMDIR) { if(m) error(Eperm); if(mkdir(path, perm & 0777) < 0) error(strerror(errno)); fd = open(path, 0); if(fd >= 0) { chmod(path, perm & 0777); chown(path, uif->uid, uif->uid); } close(fd); uif->dir = opendir(path); if(uif->dir == 0) error(strerror(errno)); } else { fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0666); if(fd >= 0) { if(m != 1) { close(fd); fd = open(path, m); } chmod(path, perm & 0777); chown(path, uif->uid, uif->gid); } if(fd < 0) error(strerror(errno)); uif->fd = fd; } if(stat(path, &stbuf) < 0) error(strerror(errno)); free(uif->path); uif->path = path; poperror(); c->qid = fsqid(&stbuf); c->offset = 0; c->flag |= COPEN; c->mode = openmode(mode); return c; } static void fsclose(Chan *c) { Ufsinfo *uif; uif = c->aux; if(c->flag & COPEN) { if(c->qid.type & QTDIR) closedir(uif->dir); else close(uif->fd); c->flag &= ~COPEN; if(c->flag & CRCLOSE) { devtab[c->type]->remove(c); return; } } free(uif->path); free(uif); } static long fsread(Chan *c, void *va, long n, vlong offset) { int fd, r; Ufsinfo *uif; /*print("fsread %s\n", chanpath(c));*/ if(c->qid.type & QTDIR) return fsdirread(c, va, n, offset); uif = c->aux; qlock(&uif->oq); if(waserror()) { qunlock(&uif->oq); nexterror(); } fd = uif->fd; if(uif->offset != offset) { r = lseek(fd, offset, 0); if(r < 0) error(strerror(errno)); uif->offset = offset; } n = read(fd, va, n); if(n < 0) error(strerror(errno)); uif->offset += n; qunlock(&uif->oq); poperror(); return n; } static long fswrite(Chan *c, void *va, long n, vlong offset) { int fd, r; Ufsinfo *uif; uif = c->aux; qlock(&uif->oq); if(waserror()) { qunlock(&uif->oq); nexterror(); } fd = uif->fd; if(uif->offset != offset) { r = lseek(fd, offset, 0); if(r < 0) error(strerror(errno)); uif->offset = offset; } n = write(fd, va, n); if(n < 0) error(strerror(errno)); uif->offset += n; qunlock(&uif->oq); poperror(); return n; } static void fsremove(Chan *c) { int n; Ufsinfo *uif; if(waserror()){ fsclose(c); nexterror(); } uif = c->aux; if(c->qid.type & QTDIR) n = rmdir(uif->path); else n = remove(uif->path); if(n < 0) error(strerror(errno)); poperror(); fsclose(c); } int fswstat(Chan *c, uchar *buf, int n) { Dir d; struct stat stbuf; char strs[NAME_MAX*3]; Ufsinfo *uif; if(convM2D(buf, n, &d, strs) != n) error(Ebadstat); uif = c->aux; if(stat(uif->path, &stbuf) < 0) error(strerror(errno)); if(~d.mode != 0 && (int)(d.mode&0777) != (int)(stbuf.st_mode&0777)) { if(chmod(uif->path, d.mode&0777) < 0) error(strerror(errno)); uif->mode &= ~0777; uif->mode |= d.mode&0777; } if(d.name[0] && strcmp(d.name, lastelem(uif->path)) != 0) { char *base, *newpath; base = strdup(uif->path); if(waserror()){ free(base); nexterror(); } *lastelem(base) = 0; newpath = catpath(base, d.name); free(base), base = newpath; if(rename(uif->path, newpath) < 0) error(strerror(errno)); free(uif->path); uif->path = newpath; poperror(); } /* p = name2pass(gid, d.gid); if(p == 0) error(Eunknown); if(p->id != stbuf.st_gid) { if(chown(old, stbuf.st_uid, p->id) < 0) error(strerror(errno)); uif->gid = p->id; } */ return n; } static Qid fsqid(struct stat *st) { Qid q; q.type = 0; if((st->st_mode&S_IFMT) == S_IFDIR) q.type = QTDIR; q.path = (uvlong)st->st_dev<<32 | st->st_ino; q.vers = st->st_mtime; return q; } static char* catpath(char *base, char *ext) { char *path; int n, m; n = strlen(base); m = strlen(ext); path = malloc(n+m+2); memmove(path, base, n); if(n > 0 && path[n-1] != '/') path[n++] = '/'; memmove(path+n, ext, m+1); return path; } static int isdots(char *name) { if(name[0] != '.') return 0; if(name[1] == '\0') return 1; if(name[1] != '.') return 0; if(name[2] == '\0') return 1; return 0; } static int p9readdir(char *name, Ufsinfo *uif) { struct dirent *de; if(uif->nextname[0]){ strcpy(name, uif->nextname); uif->nextname[0] = 0; return 1; } de = readdir(uif->dir); if(de == NULL) return 0; strcpy(name, de->d_name); return 1; } static ulong fsdirread(Chan *c, uchar *va, int count, ulong offset) { int i; Dir d; long n; char de[NAME_MAX]; struct stat stbuf; Ufsinfo *uif; /*print("fsdirread %s\n", chanpath(c));*/ i = 0; uif = c->aux; errno = 0; if(uif->offset != offset) { if(offset != 0) error("bad offset in fsdirread"); uif->offset = offset; /* sync offset */ uif->nextname[0] = 0; rewinddir(uif->dir); } while(i+BIT16SZ < count) { char *p; if(!p9readdir(de, uif)) break; if(de[0]==0 || isdots(de)) continue; d.name = de; p = catpath(uif->path, de); if(stat(p, &stbuf) < 0) { /* fprint(2, "dir: bad path %s\n", path); */ /* but continue... probably a bad symlink */ memset(&stbuf, 0, sizeof stbuf); } free(p); d.uid = eve; d.gid = eve; d.muid = eve; d.qid = fsqid(&stbuf); d.mode = (d.qid.type<<24)|(stbuf.st_mode&0777); d.atime = stbuf.st_atime; d.mtime = stbuf.st_mtime; d.length = stbuf.st_size; d.type = 'U'; d.dev = c->dev; n = convD2M(&d, (uchar*)va+i, count-i); if(n == BIT16SZ){ strcpy(uif->nextname, de); break; } i += n; } /*print("got %d\n", i);*/ uif->offset += i; return i; } static int fsomode(int m) { switch(m) { case 0: /* OREAD */ case 3: /* OEXEC */ return 0; case 1: /* OWRITE */ return 1; case 2: /* ORDWR */ return 2; } error(Ebadarg); return 0; } Dev fsdevtab = { 'U', "fs", devreset, devinit, devshutdown, fsattach, fswalk, fsstat, fsopen, fscreate, fsclose, fsread, devbread, fswrite, devbwrite, fsremove, fswstat, };