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library: protect against a future breakage, <pids> ABI

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By co-mingling both external/internal identifiers with
actual implementation code, potential future additions
to our API would have been considerably more difficult.

So, this patch will now rely solely on internal/hidden
identifiers serving as fenceposts in validation logic.

And if the following convention is used for new fields
we will maintain that enumerator alphabetic ordering a
a little longer (even though 2 user fields now don't):

. PROCPS_PIDS_XTRA_FOO_A, PROCPS_PIDS_XTRA_FOO_B, etc.

Reference(s):
http://www.freelists.org/post/procps/me-too-newlib,7

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2016-04-18 00:00:00 -05:00 committed by Craig Small
parent 4217eddf47
commit e7585992d9
2 changed files with 20 additions and 20 deletions
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32
proc/pids.c
View File

@ -52,8 +52,9 @@
#define READS_BEGUN (info->read) // a read is in progress
enum pids_item PROCPS_PIDS_logical_end = PROCPS_PIDS_noop + 1;
enum pids_item PROCPS_PIDS_physical_end = PROCPS_PIDS_noop + 2;
// next 2 MUST be kept in sync with highest value enum
enum pids_item PROCPS_PIDS_logical_end = PROCPS_PIDS_WCHAN_NAME + 1;
enum pids_item PROCPS_PIDS_physical_end = PROCPS_PIDS_WCHAN_NAME + 2;
// these represent the proc_t fields whose storage cannot be managed
// optimally if they are ever referenced more than once in any stack
@ -136,6 +137,8 @@ struct procps_pidsinfo {
if (I->ref_counts[ref_ ## e2]) R->result.strv = NULL; \
else { R->result.strv = P-> x; P-> x = NULL; } }
setDECL(noop) { (void)I; (void)R; (void)P; return; }
setDECL(extra) { (void)I; (void)R; (void)P; return; }
REG_set(ADDR_END_CODE, ul_int, end_code)
REG_set(ADDR_KSTK_EIP, ul_int, kstk_eip)
REG_set(ADDR_KSTK_ESP, ul_int, kstk_esp)
@ -253,10 +256,6 @@ setDECL(VM_USED) { (void)I; R->result.ul_int = P->vm_swap + P->vm_rss; }
REG_set(VSIZE_PGS, ul_int, vsize)
REG_set(WCHAN_ADDR, ul_int, wchan)
setDECL(WCHAN_NAME) { (void)I; R->result.str = strdup(lookup_wchan(P->tid)); }
setDECL(extra) { (void)I; (void)R; (void)P; return; }
setDECL(noop) { (void)I; (void)R; (void)P; return; }
setDECL(logical_end) { (void)I; (void)R; (void)P; return; }
setDECL(physical_end) { (void)I; (void)R; (void)P; return; }
#undef setDECL
#undef CVT_set
@ -391,6 +390,8 @@ static struct {
} Item_table[] = {
/* setsfunc oldflags freefunc sortfunc needhist refcount
--------------------- ---------- --------- ------------ -------- ------------- */
{ RS(noop), 0, NULL, QS(noop), 0, -1 }, // user only, never altered
{ RS(extra), 0, NULL, QS(ull_int), 0, -1 }, // user only, reset to zero
{ RS(ADDR_END_CODE), f_stat, NULL, QS(ul_int), 0, -1 },
{ RS(ADDR_KSTK_EIP), f_stat, NULL, QS(ul_int), 0, -1 },
{ RS(ADDR_KSTK_ESP), f_stat, NULL, QS(ul_int), 0, -1 },
@ -508,10 +509,8 @@ static struct {
{ RS(VSIZE_PGS), f_stat, NULL, QS(ul_int), 0, -1 },
{ RS(WCHAN_ADDR), f_stat, NULL, QS(ul_int), 0, -1 },
{ RS(WCHAN_NAME), 0, FF(str), QS(str), 0, -1 }, // oldflags: tid already free
{ RS(extra), 0, NULL, QS(ull_int), 0, -1 },
{ RS(noop), 0, NULL, QS(noop), 0, -1 },
{ RS(logical_end), 0, NULL, QS(noop), 0, -1 },
{ RS(physical_end), 0, NULL, QS(noop), 0, -1 }
// dummy entry never referenced ( makes future additions 'comma' worry free )...
{ NULL, 0, NULL, NULL, 0, -1 }
};
#undef RS
@ -784,11 +783,12 @@ static inline void cleanup_stack (
int i;
for (i = 0; i < depth; i++) {
if (p->item < PROCPS_PIDS_noop) {
if (p->item >= PROCPS_PIDS_logical_end)
break;
if (Item_table[p->item].freefunc)
Item_table[p->item].freefunc(p);
if (p->item > PROCPS_PIDS_noop)
p->result.ull_int = 0;
}
++p;
}
} // end: cleanup_stack
@ -869,7 +869,7 @@ static inline int items_check_failed (
// a pids_item is currently unsigned, but we'll protect our future
if (items[i] < 0)
return -1;
if (items[i] > PROCPS_PIDS_noop) {
if (items[i] >= PROCPS_PIDS_logical_end) {
return -1;
}
}
@ -1023,7 +1023,7 @@ static void validate_stacks (
* alloc_stacks():
*
* Allocate and initialize one or more stacks each of which is anchored in an
* associated pids_stack structure (which may include extra user space).
* associated pids_stack structure.
*
* All such stacks will will have their result structures properly primed with
* 'items', while the result itself will be zeroed.
@ -1438,7 +1438,7 @@ PROCPS_EXPORT struct pids_stack **procps_pids_sort (
if (info == NULL || stacks == NULL)
return NULL;
// a pids_item is currently unsigned, but we'll protect our future
if (sort < 0 || sort > PROCPS_PIDS_noop)
if (sort < 0 || sort >= PROCPS_PIDS_logical_end)
return NULL;
if (order != PROCPS_SORT_ASCEND && order != PROCPS_SORT_DESCEND)
return NULL;
@ -1453,7 +1453,7 @@ PROCPS_EXPORT struct pids_stack **procps_pids_sort (
++offset;
if (offset >= info->curitems)
return NULL;
if (p->item > PROCPS_PIDS_noop)
if (p->item >= PROCPS_PIDS_logical_end)
return NULL;
++p;
}

4
proc/pids.h
View File

@ -27,6 +27,8 @@
__BEGIN_DECLS
enum pids_item {
PROCPS_PIDS_noop, // ( never altered )
PROCPS_PIDS_extra, // ( reset to zero )
PROCPS_PIDS_ADDR_END_CODE, // ul_int
PROCPS_PIDS_ADDR_KSTK_EIP, // ul_int
PROCPS_PIDS_ADDR_KSTK_ESP, // ul_int
@ -144,8 +146,6 @@ enum pids_item {
PROCPS_PIDS_VSIZE_PGS, // ul_int
PROCPS_PIDS_WCHAN_ADDR, // ul_int
PROCPS_PIDS_WCHAN_NAME, // str
PROCPS_PIDS_extra, // ( reset to zero )
PROCPS_PIDS_noop // ( never altered )
};
enum pids_fill_type {