emo/procps
1
0
Fork 0
Code Issues Pull Requests Packages Releases Activity

library: improve and/or standardize 'errno' management

Browse Source 
With older library logic having been modified to avoid
using those potentially deadly alloc.h routines, while
improving 'errno' handling, we're ready to standardize
and enhance newlib's approach to any potential errors.

In so doing, we'll establish the following objectives:

. . . . . . . . . . . . . functions returning an 'int'
. an error will be indicated by a negative number that
is always the inverse of some well known errno.h value

. . . . . . . . . . . functions returning an 'address'
. any error will be indicated by a NULL return pointer
with the actual reason found in the formal errno value

And, when errno is manipulated directly we will strive
to do so whenever possible within those routines which
have been declared with PROCPS_EXPORT. In other words,
in the user callable functions defined in source last.

[ But, that won't always be possible. In particular, ]
[ all the 'read_failed' functions will sometimes set ]
[ 'errno' so that they can serve callers returning a ]
[ NULL or an int without duplicating a lot of logic. ]

[ Also, that includes one subordinate function which ]
[ was called by 'read_failed' in the <slabinfo> API. ]

------------------------------------------------------
Along the way, several additional miscellaneous issues
were addressed. They're listed here now for posterity.

. the '-1' return value passed outside the library was
eliminated since it would erroneously equate to -EPERM

. the stacks_fetch functions in <diskstats> and <stat>
weren't checked for their possible minus return values

. hash create was not checked in <meminfo> or <vmstat>

. fixed 'new' function faulty parm check in <slabinfo>

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner
2017-11-18 00:00:00 -05:00
committed by Craig Small
parent 7453f8719b
commit 06be33b43e
6 changed files with 262 additions and 203 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
proc/stat.c
View File

@ -473,14 +473,14 @@ static inline int stat_items_check_failed (
*/
if (numitems < 1
|| (void *)items < (void *)(unsigned long)(2 * STAT_logical_end))
return -1;
return 1;
for (i = 0; i < numitems; i++) {
// a stat_item is currently unsigned, but we'll protect our future
if (items[i] < 0)
return -1;
return 1;
if (items[i] >= STAT_logical_end) {
return -1;
return 1;
}
}
return 0;
@ -561,14 +561,14 @@ static int stat_read_failed (
if (!info->cpus.hist.n_alloc) {
info->cpus.hist.tics = calloc(NEWOLD_INCR, sizeof(struct hist_tic));
if (!(info->cpus.hist.tics))
return -ENOMEM;
return 1;
info->cpus.hist.n_alloc = NEWOLD_INCR;
info->cpus.hist.n_inuse = 0;
}
if (!info->stat_fp
&& (!(info->stat_fp = fopen(STAT_FILE, "r"))))
return -errno;
return 1;
fflush(info->stat_fp);
rewind(info->stat_fp);
@ -579,21 +579,23 @@ static int stat_read_failed (
especially in a massively parallel environment. additionally, each cpu |
line is then frozen in time rather than changing until we get around to |
accessing it. this helps to minimize (not eliminate) some distortions. | */
tot_read = errno = 0;
tot_read = 0;
while ((0 < (num = fread(curPOS, 1, curSIZ, info->stat_fp)))) {
tot_read += num;
if (tot_read < maxSIZ)
break;
maxSIZ += BUFFER_INCR;
if (!(info->stat_buf = realloc(info->stat_buf, maxSIZ)))
return -ENOMEM;
return 1;
};
#undef maxSIZ
#undef curSIZ
#undef curPOS
if (!feof(info->stat_fp))
return -errno;
if (!feof(info->stat_fp)) {
errno = EIO;
return 1;
}
info->stat_buf[tot_read] = '\0';
bp = info->stat_buf;
@ -609,8 +611,10 @@ static int stat_read_failed (
, &sum_ptr->new.user, &sum_ptr->new.nice, &sum_ptr->new.system
, &sum_ptr->new.idle, &sum_ptr->new.iowait, &sum_ptr->new.irq
, &sum_ptr->new.sirq, &sum_ptr->new.stolen
, &sum_ptr->new.guest, &sum_ptr->new.gnice))
return -1;
, &sum_ptr->new.guest, &sum_ptr->new.gnice)) {
errno = ERANGE;
return 1;
}
stat_derive_unique(sum_ptr);
i = 0;
@ -642,7 +646,7 @@ reap_em_again:
info->cpus.hist.n_alloc += NEWOLD_INCR;
info->cpus.hist.tics = realloc(info->cpus.hist.tics, info->cpus.hist.n_alloc * sizeof(struct hist_tic));
if (!(info->cpus.hist.tics))
return -ENOMEM;
return 1;
goto reap_em_again;
}
@ -756,18 +760,15 @@ static int stat_stacks_fetch (
struct stacks_extent *ext;
int i;
if (this == NULL)
return -EINVAL;
// initialize stuff -----------------------------------
if (!this->anchor) {
if (!(this->anchor = calloc(sizeof(void *), STACKS_INCR)))
return -ENOMEM;
return -1;
n_alloc = STACKS_INCR;
}
if (!this->fetch.extents) {
if (!(ext = stat_stacks_alloc(&this->fetch, n_alloc)))
return -ENOMEM;
return -1; // here, errno was set to ENOMEM
memcpy(this->anchor, ext->stacks, sizeof(void *) * n_alloc);
}
if (this->fetch.dirty_stacks)
@ -778,9 +779,8 @@ static int stat_stacks_fetch (
if (!(i < n_alloc)) {
n_alloc += STACKS_INCR;
if ((!(this->anchor = realloc(this->anchor, sizeof(void *) * n_alloc)))
|| (!(ext = stat_stacks_alloc(&this->fetch, STACKS_INCR)))) {
return -ENOMEM;
}
|| (!(ext = stat_stacks_alloc(&this->fetch, STACKS_INCR))))
return -1; // here, errno was set to ENOMEM
memcpy(this->anchor + i, ext->stacks, sizeof(void *) * STACKS_INCR);
}
stat_assign_results(this->anchor[i], &info->sys_hist, &this->hist.tics[i]);
@ -794,7 +794,7 @@ static int stat_stacks_fetch (
if (n_saved < i + 1) {
n_saved = i + 1;
if (!(this->result.stacks = realloc(this->result.stacks, sizeof(void *) * n_saved)))
return -ENOMEM;
return -1;
}
memcpy(this->result.stacks, this->anchor, sizeof(void *) * i);
this->result.stacks[i] = NULL;
@ -815,15 +815,14 @@ static int stat_stacks_reconfig_maybe (
int numitems)
{
if (stat_items_check_failed(numitems, items))
return -EINVAL;
return -1;
/* is this the first time or have things changed since we were last called?
if so, gotta' redo all of our stacks stuff ... */
if (this->items->num != numitems + 1
|| memcmp(this->items->enums, items, sizeof(enum stat_item) * numitems)) {
// allow for our STAT_logical_end
if (!(this->items->enums = realloc(this->items->enums, sizeof(enum stat_item) * (numitems + 1))))
return -ENOMEM;
return -1;
memcpy(this->items->enums, items, sizeof(enum stat_item) * numitems);
this->items->enums[numitems] = STAT_logical_end;
this->items->num = numitems + 1;
@ -872,7 +871,6 @@ PROCPS_EXPORT int procps_stat_new (
struct stat_info **info)
{
struct stat_info *p;
int rc;
if (info == NULL || *info != NULL)
return -EINVAL;
@ -901,9 +899,9 @@ PROCPS_EXPORT int procps_stat_new (
1) ensure there will be no problems with subsequent access |
2) make delta results potentially useful, even if 1st time |
3) elimnate need for history distortions 1st time 'switch' | */
if ((rc = stat_read_failed(p))) {
if (stat_read_failed(p)) {
procps_stat_unref(&p);
return rc;
return -errno;
}
*info = p;
@ -931,6 +929,8 @@ PROCPS_EXPORT int procps_stat_unref (
(*info)->refcount--;
if ((*info)->refcount < 1) {
int errno_sav = errno;
if ((*info)->stat_fp)
fclose((*info)->stat_fp);
if ((*info)->stat_buf)
@ -969,6 +969,8 @@ PROCPS_EXPORT int procps_stat_unref (
free(*info);
*info = NULL;
errno = errno_sav;
return 0;
}
return (*info)->refcount;
@ -984,10 +986,12 @@ PROCPS_EXPORT struct stat_result *procps_stat_get (
static time_t sav_secs;
time_t cur_secs;
errno = EINVAL;
if (info == NULL)
return NULL;
if (item < 0 || item >= STAT_logical_end)
return NULL;
errno = 0;
/* we will NOT read the source file with every call - rather, we'll offer
a granularity of 1 second between reads ... */
@ -999,9 +1003,8 @@ PROCPS_EXPORT struct stat_result *procps_stat_get (
}
info->get_this.item = item;
// with 'get', we must NOT honor the usual 'noop' guarantee
// if (item > STAT_noop)
info->get_this.result.ull_int = 0;
// with 'get', we must NOT honor the usual 'noop' guarantee
info->get_this.result.ull_int = 0;
Item_table[item].setsfunc(&info->get_this, &info->sys_hist, &info->cpu_hist);
return &info->get_this;
@ -1023,6 +1026,7 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
{
int rc;
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (what != STAT_REAP_CPUS_ONLY && what != STAT_REAP_CPUS_AND_NODES)
@ -1037,13 +1041,13 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
}
}
#endif
if (0 > (rc = stat_stacks_reconfig_maybe(&info->cpu_summary, items, numitems)))
return NULL;
return NULL; // here, errno may be overridden with ENOMEM
if (rc) {
stat_extents_free_all(&info->cpus.fetch);
stat_extents_free_all(&info->nodes.fetch);
}
errno = 0;
if (stat_read_failed(info))
return NULL;
@ -1060,7 +1064,7 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
switch (what) {
case STAT_REAP_CPUS_ONLY:
if (!stat_stacks_fetch(info, &info->cpus))
if (0 > stat_stacks_fetch(info, &info->cpus))
return NULL;
break;
case STAT_REAP_CPUS_AND_NODES:
@ -1069,9 +1073,9 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
will have marked (temporarily) all the cpu node ids as invalid | */
if (0 > stat_make_numa_hist(info))
return NULL;
// tolerate an unexpected absence of libnuma.so ...
stat_stacks_fetch(info, &info->nodes);
if (!stat_stacks_fetch(info, &info->cpus))
if (0 > stat_stacks_fetch(info, &info->nodes))
return NULL;
if (0 > stat_stacks_fetch(info, &info->cpus))
return NULL;
break;
default:
@ -1094,11 +1098,12 @@ PROCPS_EXPORT struct stat_stack *procps_stat_select (
enum stat_item *items,
int numitems)
{
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (0 > stat_stacks_reconfig_maybe(&info->select, items, numitems))
return NULL;
return NULL; // here, errno may be overridden with ENOMEM
errno = 0;
if (stat_read_failed(info))
return NULL;
@ -1128,9 +1133,9 @@ PROCPS_EXPORT struct stat_stack **procps_stat_sort (
struct sort_parms parms;
int offset;
errno = EINVAL;
if (info == NULL || stacks == NULL)
return NULL;
// a stat_item is currently unsigned, but we'll protect our future
if (sortitem < 0 || sortitem >= STAT_logical_end)
return NULL;
@ -1149,6 +1154,8 @@ PROCPS_EXPORT struct stat_stack **procps_stat_sort (
return NULL;
++p;
}
errno = 0;
parms.offset = offset;
parms.order = order;