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library: tweak 'other' user/group names for efficiency

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This commit just ensures that the relatively expensive
ID to name conversions aren't performed unless they're
explicitly requested. It also internalizes those flags
that required the PROC_FILLSTATUS flag to also be set.

[ requiring a caller, in our case pids.c, to provide ]
[ two flags when a single field was the objective is ]
[ wrong & represents a future potential toe-stubber. ]

[ moreover, what's worse is that those two flags are ]
[ seemingly unrelated. but, without both, a SEGV can ]
[ can be expected when a result.str pointer is NULL. ]

[ by contrast, in the master branch those fields are ]
[ arrays which, when set to zeroes, produce an empty ]
[ string. So, there is no abend (but no name either) ]
[ when one of those two required flags were omitted. ]

[ and worth noting, in that branch it's not just one ]
[ caller required to observe a two flag requirement. ]

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2021-02-02 00:00:00 -06:00 committed by Craig Small
parent 4770195b87
commit 3c87c46439
3 changed files with 35 additions and 41 deletions
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8
proc/pids.c
View File

@ -356,10 +356,10 @@ srtDECL(noop) {
#define v_arg PROC_FILLARG
#define v_cgroup PROC_FILLCGROUP
#define v_env PROC_FILLENV
// remaining are compound flags
#define x_ogroup PROC_FILLSTATUS | PROC_FILLGRP
#define x_ouser PROC_FILLSTATUS | PROC_FILLUSR
#define x_supgrp PROC_FILLSTATUS | PROC_FILLSUPGRP
// these next three will also force PROC_FILLSTATUS
#define x_ogroup PROC_FILL_OGROUPS
#define x_ouser PROC_FILL_OUSERS
#define x_supgrp PROC_FILL_SUPGRP
typedef void (*SET_t)(struct pids_info *, struct pids_result *, proc_t *);
typedef void (*FRE_t)(struct pids_result *);

58
proc/readproc.c
View File

@ -1051,8 +1051,18 @@ static proc_t* simple_readproc(PROCTAB *restrict const PT, proc_t *restrict cons
if (flags & PROC_FILLSTATUS) { // read /proc/#/status
if (file2str(path, "status", &ub) != -1){
rc += status2proc(ub.buf, p, 1);
if (flags & PROC_FILLSUPGRP)
if (flags & (PROC_FILL_SUPGRP & ~PROC_FILLSTATUS))
rc += supgrps_from_supgids(p);
if (flags & (PROC_FILL_OUSERS & ~PROC_FILLSTATUS)) {
p->ruser = pwcache_get_user(p->ruid);
p->suser = pwcache_get_user(p->suid);
p->fuser = pwcache_get_user(p->fuid);
}
if (flags & (PROC_FILL_OGROUPS & ~PROC_FILLSTATUS)) {
p->rgroup = pwcache_get_group(p->rgid);
p->sgroup = pwcache_get_group(p->sgid);
p->fgroup = pwcache_get_group(p->fgid);
}
}
}
@ -1063,25 +1073,10 @@ static proc_t* simple_readproc(PROCTAB *restrict const PT, proc_t *restrict cons
/* some number->text resolving which is time consuming */
/* ( names are cached, so memcpy to arrays was silly ) */
if (flags & PROC_FILLUSR){
if (flags & PROC_FILLUSR)
p->euser = pwcache_get_user(p->euid);
if(flags & PROC_FILLSTATUS) {
p->ruser = pwcache_get_user(p->ruid);
p->suser = pwcache_get_user(p->suid);
p->fuser = pwcache_get_user(p->fuid);
}
}
/* some number->text resolving which is time consuming */
/* ( names are cached, so memcpy to arrays was silly ) */
if (flags & PROC_FILLGRP){
if (flags & PROC_FILLGRP)
p->egroup = pwcache_get_group(p->egid);
if(flags & PROC_FILLSTATUS) {
p->rgroup = pwcache_get_group(p->rgid);
p->sgroup = pwcache_get_group(p->sgid);
p->fgroup = pwcache_get_group(p->fgid);
}
}
if (flags & PROC_FILLENV) // read /proc/#/environ
if (!(p->environ_v = file2strvec(path, "environ")))
@ -1165,32 +1160,27 @@ static proc_t* simple_readtask(PROCTAB *restrict const PT, proc_t *restrict cons
if (flags & PROC_FILLSTATUS) { // read /proc/#/task/#/status
if (file2str(path, "status", &ub) != -1) {
rc += status2proc(ub.buf, t, 0);
if (flags & PROC_FILLSUPGRP)
if (flags & (PROC_FILL_SUPGRP & ~PROC_FILLSTATUS))
rc += supgrps_from_supgids(t);
}
}
/* some number->text resolving which is time consuming */
/* ( names are cached, so memcpy to arrays was silly ) */
if (flags & PROC_FILLUSR){
t->euser = pwcache_get_user(t->euid);
if(flags & PROC_FILLSTATUS) {
if (flags & (PROC_FILL_OUSERS & ~PROC_FILLSTATUS)) {
t->ruser = pwcache_get_user(t->ruid);
t->suser = pwcache_get_user(t->suid);
t->fuser = pwcache_get_user(t->fuid);
}
}
/* some number->text resolving which is time consuming */
/* ( names are cached, so memcpy to arrays was silly ) */
if (flags & PROC_FILLGRP){
t->egroup = pwcache_get_group(t->egid);
if(flags & PROC_FILLSTATUS) {
if (flags & (PROC_FILL_OGROUPS & ~PROC_FILLSTATUS)) {
t->rgroup = pwcache_get_group(t->rgid);
t->sgroup = pwcache_get_group(t->sgid);
t->fgroup = pwcache_get_group(t->fgid);
}
}
}
/* some number->text resolving which is time consuming */
/* ( names are cached, so memcpy to arrays was silly ) */
if (flags & PROC_FILLUSR)
t->euser = pwcache_get_user(t->euid);
if (flags & PROC_FILLGRP)
t->egroup = pwcache_get_group(t->egid);
#ifdef FALSE_THREADS
if (!IS_THREAD(t)) {

6
proc/readproc.h
View File

@ -207,7 +207,6 @@ typedef struct PROCTAB {
#define PROC_FILLSTATUS 0x0020 // read status
#define PROC_FILLSTAT 0x0040 // read stat
#define PROC_FILLCGROUP 0x0200 // alloc and fill in `cgroup` vectors
#define PROC_FILLSUPGRP 0x0400 // resolve supplementary group id -> group name
#define PROC_FILLOOM 0x0800 // fill in proc_t oom_score and oom_adj
#define PROC_FILLNS 0x8000 // fill in proc_t namespace information
#define PROC_FILLSYSTEMD 0x80000 // fill in proc_t systemd information
@ -224,6 +223,11 @@ typedef struct PROCTAB {
#define PROC_EDITCMDLCVT 0x20000 // edit `cmdline' as regular string
#define PROC_EDITENVRCVT 0x40000 // edit `environ' as regular string
// these three also require the PROC_FILLSTATUS flage
#define PROC_FILL_OUSERS ( 0x0080 | PROC_FILLSTATUS ) // obtain other user names
#define PROC_FILL_OGROUPS ( 0x0100 | PROC_FILLSTATUS ) // obtain other group names
#define PROC_FILL_SUPGRP ( 0x0400 | PROC_FILLSTATUS ) // obtain supplementary group names
// it helps to give app code a few spare bits
#define PROC_SPARE_1 0x01000000
#define PROC_SPARE_2 0x02000000