diff options
Diffstat (limited to 'emu/port/devenv.c')
| -rw-r--r-- | emu/port/devenv.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/emu/port/devenv.c b/emu/port/devenv.c new file mode 100644 index 00000000..9f56ce7d --- /dev/null +++ b/emu/port/devenv.c @@ -0,0 +1,253 @@ +/* + * devenv - environment + */ +#include "dat.h" +#include "fns.h" +#include "error.h" + +enum +{ + Maxenvlen= 16*1024-1, +}; + + +static void envremove(Chan*); + +static int +envgen(Chan *c, char *name, Dirtab *d, int nd, int s, Dir *dp) +{ + Egrp *eg; + Evalue *e; + + USED(name); + USED(d); + USED(nd); + if(s == DEVDOTDOT){ + devdir(c, c->qid, "#e", 0, eve, DMDIR|0775, dp); + return 1; + } + eg = up->env->egrp; + qlock(&eg->l); + for(e = eg->entries; e != nil && s != 0; e = e->next) + s--; + if(e == nil) { + qunlock(&eg->l); + return -1; + } + /* make sure name string continues to exist after we release lock */ + kstrcpy(up->genbuf, e->var, sizeof up->genbuf); + devdir(c, e->qid, up->genbuf, e->len, eve, 0666, dp); + qunlock(&eg->l); + return 1; +} + +static Chan* +envattach(char *spec) +{ + return devattach('e', spec); +} + +static Walkqid* +envwalk(Chan *c, Chan *nc, char **name, int nname) +{ + return devwalk(c, nc, name, nname, 0, 0, envgen); +} + +static int +envstat(Chan *c, uchar *db, int n) +{ + if(c->qid.type & QTDIR) + c->qid.vers = up->env->egrp->vers; + return devstat(c, db, n, 0, 0, envgen); +} + +static Chan * +envopen(Chan *c, int mode) +{ + Egrp *eg; + Evalue *e; + + if(c->qid.type & QTDIR) { + if(mode != OREAD) + error(Eperm); + c->mode = mode; + c->flag |= COPEN; + c->offset = 0; + return c; + } + eg = up->env->egrp; + qlock(&eg->l); + for(e = eg->entries; e != nil; e = e->next) + if(e->qid.path == c->qid.path) + break; + if(e == nil) { + qunlock(&eg->l); + error(Enonexist); + } + if(mode == (OWRITE|OTRUNC) && e->val) { + free(e->val); + e->val = 0; + e->len = 0; + e->qid.vers++; + } + qunlock(&eg->l); + c->offset = 0; + c->flag |= COPEN; + c->mode = mode&~OTRUNC; + return c; +} + +static void +envcreate(Chan *c, char *name, int mode, ulong perm) +{ + Egrp *eg; + Evalue *e, *le; + + USED(perm); + if(c->qid.type != QTDIR) + error(Eperm); + if(strlen(name) >= sizeof(up->genbuf)) + error("name too long"); /* needs to fit for stat */ + eg = up->env->egrp; + qlock(&eg->l); + for(le = nil, e = eg->entries; e != nil; le = e, e = e->next) + if(strcmp(e->var, name) == 0) { + qunlock(&eg->l); + error(Eexist); + } + e = smalloc(sizeof(Evalue)); + e->var = smalloc(strlen(name)+1); + strcpy(e->var, name); + e->val = 0; + e->len = 0; + e->qid.path = ++eg->path; + if (le == nil) + eg->entries = e; + else + le->next = e; + e->qid.vers = 0; + c->qid = e->qid; + eg->vers++; + qunlock(&eg->l); + c->offset = 0; + c->flag |= COPEN; + c->mode = mode; +} + +static void +envclose(Chan * c) +{ + if(c->flag & CRCLOSE) + envremove(c); +} + +static long +envread(Chan *c, void *a, long n, vlong offset) +{ + Egrp *eg; + Evalue *e; + + if(c->qid.type & QTDIR) + return devdirread(c, a, n, 0, 0, envgen); + eg = up->env->egrp; + qlock(&eg->l); + for(e = eg->entries; e != nil; e = e->next) + if(e->qid.path == c->qid.path) + break; + if(e == nil) { + qunlock(&eg->l); + error(Enonexist); + } + if(offset > e->len) /* protects against overflow converting vlong to ulong */ + n = 0; + else if(offset + n > e->len) + n = e->len - offset; + if(n <= 0) + n = 0; + else + memmove(a, e->val+offset, n); + qunlock(&eg->l); + return n; +} + +static long +envwrite(Chan *c, void *a, long n, vlong offset) +{ + char *s; + ulong ve; + Egrp *eg; + Evalue *e; + + if(n <= 0) + return 0; + ve = offset+n; + if(ve > Maxenvlen) + error(Etoobig); + eg = up->env->egrp; + qlock(&eg->l); + for(e = eg->entries; e != nil; e = e->next) + if(e->qid.path == c->qid.path) + break; + if(e == nil) { + qunlock(&eg->l); + error(Enonexist); + } + if(ve > e->len) { + s = smalloc(ve); + memmove(s, e->val, e->len); + if(e->val) + free(e->val); + e->val = s; + e->len = ve; + } + memmove(e->val+offset, a, n); + e->qid.vers++; + qunlock(&eg->l); + return n; +} + +static void +envremove(Chan *c) +{ + Egrp *eg; + Evalue *e, **l; + + if(c->qid.type & QTDIR) + error(Eperm); + eg = up->env->egrp; + qlock(&eg->l); + for(l = &eg->entries; *l != nil; l = &(*l)->next) + if((*l)->qid.path == c->qid.path) + break; + e = *l; + if(e == nil) { + qunlock(&eg->l); + error(Enonexist); + } + *l = e->next; + eg->vers++; + qunlock(&eg->l); + free(e->var); + if(e->val != nil) + free(e->val); + free(e); +} + +Dev envdevtab = { + 'e', + "env", + + devinit, + envattach, + envwalk, + envstat, + envopen, + envcreate, + envclose, + envread, + devbread, + envwrite, + devbwrite, + envremove, + devwstat +}; |