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library: tweak support for get/select/reap, <PIDS> api

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When the <pids> api was refactored in the commit shown
below, one objective was enabling the simultaneous use
of 'get' & 'select/reap' functions. Unlike other 'get'
functions, this <pids> 'get' acts as an iterator where
successive calls will return successive tasks/threads.

However, that goal wasn't quite met since a stack used
by 'get' was commingled with the 'select/reap' stacks.
Such commingling supported the 'reset' function, again
a provision which was unique to this <pids> interface.

Unfortunately, some poor assumptions in 'stacks_fetch'
produced a SEGV whenever 'reap/select' followed 'get'.
Thus, this patch addresses those issues and guarantees
such commingled stacks (extents) will be accommodated.

Reference(s):
. standardize portions of interface, <PIDS> api
commit 9ebadc1438

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2019-05-02 00:00:00 -05:00 committed by Craig Small
parent a9bfb186eb
commit f87fc7dc83
1 changed files with 19 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
proc/pids.c
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@ -86,7 +86,7 @@ struct pids_info {
unsigned long hertz; // for TIME_ALL & TIME_ELAPSED calculations
unsigned long long boot_seconds; // for TIME_ELAPSED calculation
PROCTAB *get_PT; // oldlib interface for active 'get'
struct stacks_extent *get_ext; // an extent used for active 'get'
struct stacks_extent *get_ext; // for active 'get' (also within 'extents')
enum pids_fetch_type get_type; // last known type of 'get' request
int seterr; // an ENOMEM encountered during assign
};
@ -1047,13 +1047,10 @@ static int pids_stacks_fetch (
if (!info->fetch.anchor) {
if (!(info->fetch.anchor = calloc(sizeof(void *), STACKS_INCR)))
return -1;
n_alloc = STACKS_INCR;
}
if (!info->extents) {
if (!(ext = pids_stacks_alloc(info, n_alloc)))
if (!(ext = pids_stacks_alloc(info, STACKS_INCR)))
return -1; // here, errno was set to ENOMEM
memset(info->fetch.anchor, 0, sizeof(void *) * n_alloc);
memcpy(info->fetch.anchor, ext->stacks, sizeof(void *) * n_alloc);
memcpy(info->fetch.anchor, ext->stacks, sizeof(void *) * STACKS_INCR);
n_alloc = STACKS_INCR;
}
pids_cleanup_stacks_all(info);
pids_toggle_history(info);
@ -1223,6 +1220,9 @@ PROCPS_EXPORT int procps_pids_unref (
free((*info)->hist);
}
if ((*info)->get_ext)
pids_oldproc_close(&(*info)->get_PT);
numa_uninit();
free(*info);
@ -1288,10 +1288,10 @@ PROCPS_EXPORT struct pids_stack *procps_pids_get (
if (!info->curitems)
return NULL;
fresh_start:
if (!info->get_ext) {
if (!(info->get_ext = pids_stacks_alloc(info, 1)))
return NULL; // here, errno was overridden with ENOMEM
fresh_start:
if (!pids_oldproc_open(&info->get_PT, info->oldflags))
return NULL; // here, errno was overridden with ENOMEM/others
info->get_type = which;
@ -1300,10 +1300,6 @@ fresh_start:
if (info->get_type != which) {
pids_oldproc_close(&info->get_PT);
pids_cleanup_stack(info->get_ext->stacks[0]->head);
if (pids_extent_cut(info, info->get_ext))
free(info->get_ext);
info->get_ext = NULL;
goto fresh_start;
}
errno = 0;
@ -1364,6 +1360,9 @@ PROCPS_EXPORT int procps_pids_reset (
if (pids_items_check_failed(newitems, newnumitems))
return -EINVAL;
if (info->dirty_stacks)
pids_cleanup_stacks_all(info);
/* shame on this caller, they didn't change anything. and unless they have
altered the depth of the stacks we're not gonna change anything either! */
if (info->curitems == newnumitems + 1
@ -1371,22 +1370,25 @@ PROCPS_EXPORT int procps_pids_reset (
return 0;
if (info->maxitems < newnumitems + 1) {
if (info->dirty_stacks)
pids_cleanup_stacks_all(info);
while (info->extents) {
struct stacks_extent *p = info->extents;
info->extents = p->next;
free(p);
};
if (info->get_ext) {
pids_oldproc_close(&info->get_PT);
info->get_ext = NULL;
}
if (info->fetch.anchor) {
free(info->fetch.anchor);
info->fetch.anchor = NULL;
}
// allow for our PIDS_logical_end
info->maxitems = newnumitems + 1;
if (!(info->items = realloc(info->items, sizeof(enum pids_item) * info->maxitems)))
return -ENOMEM;
}
if (info->dirty_stacks)
pids_cleanup_stacks_all(info);
memcpy(info->items, newitems, sizeof(enum pids_item) * newnumitems);
info->items[newnumitems] = PIDS_logical_end;
// account for above PIDS_logical_end