devenv: allow environment total size of up to 1MB
Sometimes, there is the one-off occation when one needs to pass a huge list in rc... This change makes devenv track total memory consumption of environment groups allowing them to grow up to 1MB in size (including overhead). (Before, only the variable size was restricted, but not the amount of files being created). The maximum value size of a single environment variable is set to half of the total size, which allows the occational large value. (But not many of them). Because we track all memory consuption, it is also now possible to create around 10k small environment variales. A hashtable is added for name lookups and the qid.path was changed to allow direct indexing into the entry array without needing a scan lookup. All smalloc() calls have been removed, exhaustion is handled with error(Enomem) avoiding deadlock in case we run out of kernel memory.
This commit is contained in:
cinap_lenrek
parent
a5a8a92adf
commit
60adc40118
3 changed files with 235 additions and 151 deletions
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@ -58,6 +58,3 @@ in
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.IR plan9.ini (8)
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.SH SOURCE
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.B /sys/src/9/port/devenv.c
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.SH BUGS
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A write starting at an offset after the current extent of a file
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yields an error instead of zero filling.
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@ -7,27 +7,53 @@
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enum
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{
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Maxenvsize = 1*MB,
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Maxvalsize = Maxenvsize/2,
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DELTAENV = 32,
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Maxenvsize = 16300,
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};
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static Egrp *envgrp(Chan *c);
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static int envwriteable(Chan *c);
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static int envwritable(Chan *c);
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static Egrp confegrp; /* global environment group containing the kernel configuration */
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static Evalue*
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envlookup(Egrp *eg, char *name, ulong qidpath)
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{
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Evalue *e, *ee;
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#define PATH(p,i) ((uvlong)(p) << 32 | (i))
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#define QID(quidpath) ((uint)(quidpath) & 0x7FFFFFFF)
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e = eg->ent;
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for(ee = e + eg->nent; e < ee; e++){
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if(e->qid.path == qidpath
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|| (name != nil && name[0] == e->name[0] && strcmp(e->name, name) == 0))
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return e;
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static Evalue*
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envindex(Egrp *eg, uvlong qidpath)
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{
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Evalue *e;
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int i;
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i = QID(qidpath);
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if(i >= eg->nent)
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return nil;
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e = eg->ent[i];
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if(e != nil && e->path != qidpath)
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return nil;
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return e;
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}
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static Evalue**
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envhash(Egrp *eg, char *name)
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{
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uint c, h = 0;
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while(c = *name++)
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h = h*131 + c;
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return &eg->hash[h % ENVHASH];
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}
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static Evalue*
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lookupname(Evalue *e, char *name)
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{
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while(e != nil){
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if(strcmp(e->name, name) == 0)
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break;
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e = e->hash;
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}
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return nil;
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return e;
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}
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static int
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@ -35,28 +61,40 @@ envgen(Chan *c, char *name, Dirtab*, int, int s, Dir *dp)
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{
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Egrp *eg;
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Evalue *e;
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Qid q;
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eg = envgrp(c);
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if(s == DEVDOTDOT){
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c->qid.vers = eg->vers;
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devdir(c, c->qid, "#e", 0, eve, 0775, dp);
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return 1;
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}
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eg = envgrp(c);
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rlock(eg);
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if(name != nil)
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e = envlookup(eg, name, -1);
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else if(s < eg->nent)
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e = &eg->ent[s];
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else
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e = nil;
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if(e == nil || name != nil && (strlen(e->name) >= sizeof(up->genbuf))) {
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if((c->qid.type & QTDIR) == 0) {
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e = envindex(eg, c->qid.path);
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if(e == nil)
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goto Notfound;
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} else if(name != nil) {
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if(strlen(name) >= sizeof(up->genbuf))
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goto Notfound;
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e = lookupname(*envhash(eg, name), name);
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if(e == nil)
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goto Notfound;
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} else if(s < eg->nent) {
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e = eg->ent[s];
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if(e == nil) {
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runlock(eg);
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return 0; /* deleted, try next */
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}
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} else {
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Notfound:
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runlock(eg);
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return -1;
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}
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/* make sure name string continues to exist after we release lock */
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kstrcpy(up->genbuf, e->name, sizeof up->genbuf);
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devdir(c, e->qid, up->genbuf, e->len, eve,
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kstrcpy(up->genbuf, e->name, sizeof(up->genbuf));
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mkqid(&q, e->path, e->vers, QTFILE);
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devdir(c, q, up->genbuf, e->len, eve,
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eg == &confegrp || eg != up->egrp ? 0664: 0666, dp);
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runlock(eg);
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return 1;
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@ -82,15 +120,34 @@ envattach(char *spec)
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static Walkqid*
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envwalk(Chan *c, Chan *nc, char **name, int nname)
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{
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return devwalk(c, nc, name, nname, 0, 0, envgen);
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return devwalk(c, nc, name, nname, nil, 0, envgen);
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}
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static int
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envstat(Chan *c, uchar *db, int n)
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{
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if(c->qid.type & QTDIR)
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c->qid.vers = envgrp(c)->vers;
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return devstat(c, db, n, 0, 0, envgen);
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return devstat(c, db, n, nil, 0, envgen);
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}
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static void*
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envrealloc(Egrp *eg, void *old, int newsize)
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{
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int oldsize = old != nil ? msize(old) : 0;
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void *new;
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if(newsize == 0){
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eg->alloc -= oldsize;
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free(old);
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return nil;
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}
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if(newsize < 0 || eg != &confegrp && (eg->alloc + newsize) - oldsize > Maxenvsize)
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error(Enomem);
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new = realloc(old, newsize);
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if(new == nil)
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error(Enomem);
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eg->alloc += msize(new) - oldsize;
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setmalloctag(new, getcallerpc(&eg));
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return new;
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}
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static Chan*
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@ -98,7 +155,6 @@ envopen(Chan *c, int omode)
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{
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Egrp *eg;
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Evalue *e;
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int trunc;
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eg = envgrp(c);
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if(c->qid.type & QTDIR) {
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@ -106,14 +162,14 @@ envopen(Chan *c, int omode)
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error(Eperm);
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}
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else {
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trunc = omode & OTRUNC;
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if(omode != OREAD && !envwriteable(c))
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int trunc = omode & OTRUNC;
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if(omode != OREAD && !envwritable(c))
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error(Eperm);
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if(trunc)
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wlock(eg);
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else
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rlock(eg);
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e = envlookup(eg, nil, c->qid.path);
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e = envindex(eg, c->qid.path);
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if(e == nil) {
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if(trunc)
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wunlock(eg);
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@ -121,12 +177,12 @@ envopen(Chan *c, int omode)
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runlock(eg);
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error(Enonexist);
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}
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if(trunc && e->value != nil) {
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e->qid.vers++;
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free(e->value);
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e->value = nil;
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if(trunc && e->len > 0) {
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e->value = envrealloc(eg, e->value, 0); /* free */
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e->len = 0;
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e->vers++;
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}
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c->qid.vers = e->vers;
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if(trunc)
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wunlock(eg);
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else
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@ -144,12 +200,14 @@ static Chan*
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envcreate(Chan *c, char *name, int omode, ulong)
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{
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Egrp *eg;
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Evalue *e;
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Evalue *e, **h;
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int n, i;
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if(c->qid.type != QTDIR || !envwriteable(c))
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if(c->qid.type != QTDIR || !envwritable(c))
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error(Eperm);
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if(strlen(name) >= sizeof(up->genbuf))
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n = strlen(name)+1;
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if(n > sizeof(up->genbuf))
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error(Etoolong);
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omode = openmode(omode);
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@ -160,28 +218,33 @@ envcreate(Chan *c, char *name, int omode, ulong)
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nexterror();
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}
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if(envlookup(eg, name, -1) != nil)
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h = envhash(eg, name);
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if(lookupname(*h, name) != nil)
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error(Eexist);
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if(eg->nent == eg->ment){
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Evalue *tmp;
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for(i = eg->low; i < eg->nent; i++)
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if(eg->ent[i] == nil)
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break;
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eg->ment += DELTAENV;
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if((tmp = realloc(eg->ent, sizeof(eg->ent[0])*eg->ment)) == nil){
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eg->ment -= DELTAENV;
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error(Enomem);
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}
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eg->ent = tmp;
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if(i >= eg->nent){
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if((eg->nent % DELTAENV) == 0)
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eg->ent = envrealloc(eg, eg->ent, (eg->nent+DELTAENV) * sizeof(Evalue*));
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i = eg->nent++;
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eg->ent[i] = nil;
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eg->low = i;
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}
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eg->vers++;
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e = &eg->ent[eg->nent++];
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e = envrealloc(eg, nil, sizeof(Evalue)+n);
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memmove(e->name, name, n);
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e->value = nil;
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e->len = 0;
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e->name = smalloc(strlen(name)+1);
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strcpy(e->name, name);
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mkqid(&e->qid, ++eg->path, 0, QTFILE);
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c->qid = e->qid;
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e->vers = 0;
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e->path = PATH(++eg->path, i);
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e->hash = *h, *h = e;
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eg->ent[i] = e;
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eg->low = i+1;
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eg->vers++;
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mkqid(&c->qid, e->path, e->vers, QTFILE);
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wunlock(eg);
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poperror();
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incref(eg);
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@ -196,22 +259,35 @@ static void
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envremove(Chan *c)
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{
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Egrp *eg;
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Evalue *e;
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Evalue *e, **h;
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int i;
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if(c->qid.type & QTDIR || !envwriteable(c))
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if(c->qid.type & QTDIR || !envwritable(c))
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error(Eperm);
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eg = envgrp(c);
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wlock(eg);
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e = envlookup(eg, nil, c->qid.path);
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e = envindex(eg, c->qid.path);
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if(e == nil){
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wunlock(eg);
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error(Enonexist);
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}
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free(e->name);
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free(e->value);
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*e = eg->ent[--eg->nent];
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for(h = envhash(eg, e->name); *h != nil; h = &(*h)->hash){
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if(*h == e){
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*h = e->hash;
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break;
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}
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}
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i = QID(c->qid.path);
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eg->ent[i] = nil;
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if(i < eg->low)
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eg->low = i;
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eg->vers++;
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/* free */
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envrealloc(eg, e->value, 0);
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envrealloc(eg, e, 0);
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wunlock(eg);
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}
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@ -238,10 +314,9 @@ envread(Chan *c, void *a, long n, vlong off)
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{
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Egrp *eg;
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Evalue *e;
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ulong offset = off;
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if(c->qid.type & QTDIR)
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return devdirread(c, a, n, 0, 0, envgen);
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return devdirread(c, a, n, nil, 0, envgen);
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eg = envgrp(c);
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rlock(eg);
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@ -249,19 +324,17 @@ envread(Chan *c, void *a, long n, vlong off)
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runlock(eg);
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nexterror();
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}
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e = envlookup(eg, nil, c->qid.path);
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e = envindex(eg, c->qid.path);
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if(e == nil)
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error(Enonexist);
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if(offset >= e->len || e->value == nil)
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if(off >= e->len)
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n = 0;
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else if(offset + n > e->len)
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n = e->len - offset;
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else if(off + n > e->len)
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n = e->len - off;
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if(n <= 0)
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n = 0;
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else
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memmove(a, e->value+offset, n);
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memmove(a, e->value+off, n);
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runlock(eg);
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poperror();
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return n;
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@ -270,16 +343,9 @@ envread(Chan *c, void *a, long n, vlong off)
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static long
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envwrite(Chan *c, void *a, long n, vlong off)
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{
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char *s;
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ulong len;
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Egrp *eg;
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Evalue *e;
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ulong offset = off;
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if(n <= 0)
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return 0;
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if(offset > Maxenvsize || n > (Maxenvsize - offset))
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error(Etoobig);
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int diff;
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eg = envgrp(c);
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wlock(eg);
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@ -287,24 +353,22 @@ envwrite(Chan *c, void *a, long n, vlong off)
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wunlock(eg);
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nexterror();
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}
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e = envlookup(eg, nil, c->qid.path);
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e = envindex(eg, c->qid.path);
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if(e == nil)
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error(Enonexist);
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len = offset+n;
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if(len > e->len) {
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s = realloc(e->value, len);
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if(s == nil)
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error(Enomem);
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memset(s+offset, 0, n);
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e->value = s;
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e->len = len;
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}
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memmove(e->value+offset, a, n);
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e->qid.vers++;
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if(off > Maxvalsize || n > (Maxvalsize - off))
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error(Etoobig);
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diff = (off+n) - e->len;
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if(diff > 0)
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e->value = envrealloc(eg, e->value, e->len+diff);
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else
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diff = 0;
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memmove(e->value+off, a, n); /* might fault */
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if(off > e->len)
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memset(e->value+e->len, 0, off-e->len);
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e->len += diff;
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e->vers++;
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eg->vers++;
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wunlock(eg);
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poperror();
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return n;
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@ -334,41 +398,58 @@ Dev envdevtab = {
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void
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envcpy(Egrp *to, Egrp *from)
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{
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Evalue *e, *ee, *ne;
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Evalue *e, *ne, **h;
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int i, n;
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rlock(from);
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to->ment = ROUND(from->nent, DELTAENV);
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to->ent = smalloc(to->ment*sizeof(to->ent[0]));
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ne = to->ent;
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e = from->ent;
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for(ee = e + from->nent; e < ee; e++, ne++){
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ne->name = smalloc(strlen(e->name)+1);
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strcpy(ne->name, e->name);
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if(e->value != nil){
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ne->value = smalloc(e->len);
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if(waserror()){
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runlock(from);
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nexterror();
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}
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to->nent = 0;
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to->ent = envrealloc(to, nil, ROUND(from->nent, DELTAENV) * sizeof(Evalue*));
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for(i = 0; i < from->nent; i++){
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e = from->ent[i];
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if(e == nil)
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continue;
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h = envhash(to, e->name);
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n = strlen(e->name)+1;
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ne = envrealloc(to, nil, sizeof(Evalue)+n);
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memmove(ne->name, e->name, n);
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ne->value = nil;
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ne->len = 0;
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ne->vers = 0;
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ne->path = PATH(++to->path, to->nent);
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ne->hash = *h, *h = ne;
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to->ent[to->nent++] = ne;
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if(e->len > 0){
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ne->value = envrealloc(to, ne->value, e->len);
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memmove(ne->value, e->value, e->len);
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ne->len = e->len;
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}
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mkqid(&ne->qid, ++to->path, 0, QTFILE);
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}
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to->nent = from->nent;
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to->low = to->nent;
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runlock(from);
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poperror();
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}
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void
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closeegrp(Egrp *eg)
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{
|
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Evalue *e, *ee;
|
||||
Evalue *e;
|
||||
int i;
|
||||
|
||||
if(decref(eg) == 0 && eg != &confegrp){
|
||||
e = eg->ent;
|
||||
for(ee = e + eg->nent; e < ee; e++){
|
||||
free(e->name);
|
||||
free(e->value);
|
||||
}
|
||||
free(eg->ent);
|
||||
free(eg);
|
||||
if(decref(eg) || eg == &confegrp)
|
||||
return;
|
||||
for(i = 0; i < eg->nent; i++){
|
||||
e = eg->ent[i];
|
||||
if(e == nil)
|
||||
continue;
|
||||
free(e->value);
|
||||
free(e);
|
||||
}
|
||||
free(eg->ent);
|
||||
free(eg);
|
||||
}
|
||||
|
||||
static Egrp*
|
||||
|
|
@ -380,7 +461,7 @@ envgrp(Chan *c)
|
|||
}
|
||||
|
||||
static int
|
||||
envwriteable(Chan *c)
|
||||
envwritable(Chan *c)
|
||||
{
|
||||
return c->aux == nil || c->aux == up->egrp || iseve();
|
||||
}
|
||||
|
|
@ -409,38 +490,38 @@ char *
|
|||
getconfenv(void)
|
||||
{
|
||||
Egrp *eg = &confegrp;
|
||||
Evalue *e, *ee;
|
||||
Evalue *e;
|
||||
char *p, *q;
|
||||
int n;
|
||||
int i, n;
|
||||
|
||||
rlock(eg);
|
||||
if(waserror()) {
|
||||
runlock(eg);
|
||||
nexterror();
|
||||
n = 1;
|
||||
for(i = 0; i < eg->nent; i++){
|
||||
e = eg->ent[i];
|
||||
if(e == nil)
|
||||
continue;
|
||||
n += strlen(e->name)+e->len+2;
|
||||
}
|
||||
|
||||
/* determine size */
|
||||
n = 0;
|
||||
e = eg->ent;
|
||||
for(ee = e + eg->nent; e < ee; e++)
|
||||
n += strlen(e->name) + e->len + 2;
|
||||
|
||||
p = malloc(n + 1);
|
||||
if(p == nil)
|
||||
p = malloc(n);
|
||||
if(p == nil){
|
||||
runlock(eg);
|
||||
error(Enomem);
|
||||
}
|
||||
q = p;
|
||||
e = eg->ent;
|
||||
for(ee = e + eg->nent; e < ee; e++){
|
||||
strcpy(q, e->name);
|
||||
q += strlen(q) + 1;
|
||||
for(i = 0; i < eg->nent; i++){
|
||||
e = eg->ent[i];
|
||||
if(e == nil)
|
||||
continue;
|
||||
n = strlen(e->name)+1;
|
||||
memmove(q, e->name, n);
|
||||
q += n;
|
||||
memmove(q, e->value, e->len);
|
||||
q[e->len] = 0;
|
||||
/* move up to the first null */
|
||||
q += strlen(q) + 1;
|
||||
}
|
||||
*q = '\0';
|
||||
|
||||
runlock(eg);
|
||||
poperror();
|
||||
|
||||
return p;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -456,6 +456,8 @@ enum
|
|||
NFD = 100, /* per process file descriptors */
|
||||
PGHLOG = 9,
|
||||
PGHSIZE = 1<<PGHLOG, /* Page hash for image lookup */
|
||||
ENVLOG = 5,
|
||||
ENVHASH = 1<<ENVLOG, /* Egrp hash for variable lookup */
|
||||
};
|
||||
#define REND(p,s) ((p)->rendhash[(s)&((1<<RENDLOG)-1)])
|
||||
#define MOUNTH(p,qid) ((p)->mnthash[(qid).path&((1<<MNTLOG)-1)])
|
||||
|
|
@ -493,23 +495,27 @@ struct Rgrp
|
|||
Proc *rendhash[RENDHASH]; /* Rendezvous tag hash */
|
||||
};
|
||||
|
||||
struct Evalue
|
||||
{
|
||||
char *value;
|
||||
int len;
|
||||
ulong vers;
|
||||
uvlong path; /* qid.path: Egrp.path << 32 | index (of Egrp.ent[]) */
|
||||
Evalue *hash;
|
||||
char name[];
|
||||
};
|
||||
|
||||
struct Egrp
|
||||
{
|
||||
Ref;
|
||||
RWlock;
|
||||
Evalue *ent;
|
||||
int nent;
|
||||
int ment;
|
||||
ulong path; /* qid.path of next Evalue to be allocated */
|
||||
ulong vers; /* of Egrp */
|
||||
};
|
||||
|
||||
struct Evalue
|
||||
{
|
||||
char *name;
|
||||
char *value;
|
||||
int len;
|
||||
Qid qid;
|
||||
Evalue **ent;
|
||||
int nent; /* numer of slots in ent[] */
|
||||
int low; /* lowest free index in ent[] */
|
||||
int alloc; /* bytes allocated for env */
|
||||
ulong path; /* generator for qid path */
|
||||
ulong vers; /* of Egrp */
|
||||
Evalue *hash[ENVHASH]; /* hashtable for name lookup */
|
||||
};
|
||||
|
||||
struct Fgrp
|
||||
|
|
|
|||
Loading…
Reference in a new issue