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library: improve and/or standardize 'errno' management

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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

111
proc/slabinfo.c
View File

@ -320,16 +320,16 @@ static int alloc_slabnodes (
int new_count;
if (info->nodes_used < info->nodes_alloc)
return 0;
return 1;
/* Increment the allocated number of slabs */
new_count = info->nodes_alloc * 5/4+30;
new_nodes = realloc(info->nodes, sizeof(struct slabs_node) * new_count);
if (!new_nodes)
return -ENOMEM;
return 0;
info->nodes = new_nodes;
info->nodes_alloc = new_count;
return 0;
return 1;
} // end: alloc_slabnodes
@ -345,14 +345,12 @@ static int get_slabnode (
struct slabinfo_info *info,
struct slabs_node **node)
{
int retval;
if (info->nodes_used == info->nodes_alloc) {
if ((retval = alloc_slabnodes(info)) < 0)
return retval;
if (!alloc_slabnodes(info))
return 0; // here, errno was set to ENOMEM
}
*node = &(info->nodes[info->nodes_used++]);
return 0;
return 1;
} // end: get_slabnode
@ -393,7 +391,6 @@ static int parse_slabinfo20 (
{
struct slabs_node *node;
char buffer[SLABINFO_LINE_LEN];
int retval;
int page_size = getpagesize();
struct slabs_summ *slabs = &(info->slabs.new);
@ -404,8 +401,8 @@ static int parse_slabinfo20 (
if (buffer[0] == '#')
continue;
if ((retval = get_slabnode(info, &node)) < 0)
return retval;
if (!get_slabnode(info, &node))
return 1; // here, errno was set to ENOMEM
if (sscanf(buffer,
"%" STRINGIFY(SLABINFO_NAME_LEN) "s" \
@ -415,9 +412,8 @@ static int parse_slabinfo20 (
&node->obj_size, &node->objs_per_slab,
&node->pages_per_slab, &node->nr_active_slabs,
&node->nr_slabs) < 8) {
if (errno != 0)
return -errno;
return -EINVAL;
errno = ERANGE;
return 1;
}
if (!node->name[0])
@ -428,8 +424,7 @@ static int parse_slabinfo20 (
if (node->obj_size > slabs->max_obj_size)
slabs->max_obj_size = node->obj_size;
node->cache_size = (unsigned long)node->nr_slabs * node->pages_per_slab
* page_size;
node->cache_size = (unsigned long)node->nr_slabs * node->pages_per_slab * page_size;
if (node->nr_objs) {
node->use = (unsigned int)100 * (node->nr_active_objs / node->nr_objs);
@ -459,42 +454,40 @@ static int parse_slabinfo20 (
* Read the data out of /proc/slabinfo putting the information
* into the supplied info container
*
* Returns: 0 on success, negative on error
* Returns: 0 on success, 1 on error
*/
static int slabinfo_read_failed (
struct slabinfo_info *info)
{
char line[SLABINFO_LINE_LEN];
int retval, major, minor;
int major, minor;
memcpy(&info->slabs.old, &info->slabs.new, sizeof(struct slabs_summ));
memset(&(info->slabs.new), 0, sizeof(struct slabs_summ));
if ((retval = alloc_slabnodes(info)) < 0)
return retval;
if (!alloc_slabnodes(info))
return 1; // here, errno was set to ENOMEM
memset(info->nodes, 0, sizeof(struct slabs_node)*info->nodes_alloc);
info->nodes_used = 0;
if (NULL == info->slabinfo_fp
&& (info->slabinfo_fp = fopen(SLABINFO_FILE, "r")) == NULL)
return -errno;
return 1;
if (fseek(info->slabinfo_fp, 0L, SEEK_SET) < 0)
return -errno;
return 1;
/* Parse the version string */
if (!fgets(line, SLABINFO_LINE_LEN, info->slabinfo_fp))
return -errno;
return 1;
if (sscanf(line, "slabinfo - version: %d.%d", &major, &minor) != 2)
return -EINVAL;
if (2 != sscanf(line, "slabinfo - version: %d.%d", &major, &minor)
|| (major != 2)) {
errno = ERANGE;
return 1;
}
if (major == 2)
retval = parse_slabinfo20(info);
else
return -ERANGE;
return retval;
return parse_slabinfo20(info);
} // end: slabinfo_read_failed
@ -607,7 +600,7 @@ static inline int slabinfo_items_check_failed (
*/
if (numitems < 1
|| (void *)items < (void *)(unsigned long)(2 * SLABINFO_logical_end))
return -1;
return 1;
for (i = 0; i < numitems; i++) {
#ifdef ENFORCE_LOGICAL
@ -616,13 +609,13 @@ static inline int slabinfo_items_check_failed (
continue;
if (items[i] < this->lowest
|| (items[i] > this->highest))
return -1;
return 1;
#else
// a slabinfo_item is currently unsigned, but we'll protect our future
if (items[i] < 0)
return -1;
return 1;
if (items[i] >= SLABINFO_logical_end)
return -1;
return 1;
#endif
}
@ -702,12 +695,12 @@ static int slabinfo_stacks_fetch (
// initialize stuff -----------------------------------
if (!info->fetch.anchor) {
if (!(info->fetch.anchor = calloc(sizeof(void *), STACKS_INCR)))
return -ENOMEM;
return -1;
n_alloc = STACKS_INCR;
}
if (!info->fetch_ext.extents) {
if (!(ext = slabinfo_stacks_alloc(&info->fetch_ext, n_alloc)))
return -ENOMEM;
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);
slabinfo_itemize_stacks_all(&info->fetch_ext);
@ -721,7 +714,7 @@ static int slabinfo_stacks_fetch (
n_alloc += STACKS_INCR;
if ((!(info->fetch.anchor = realloc(info->fetch.anchor, sizeof(void *) * n_alloc)))
|| (!(ext = slabinfo_stacks_alloc(&info->fetch_ext, STACKS_INCR))))
return -1;
return -1; // here, errno was set to ENOMEM
memcpy(info->fetch.anchor + n_inuse, ext->stacks, sizeof(void *) * STACKS_INCR);
}
slabinfo_assign_results(info->fetch.anchor[n_inuse], &info->slabs, &info->nodes[n_inuse]);
@ -736,7 +729,7 @@ static int slabinfo_stacks_fetch (
if (n_saved < n_inuse + 1) {
n_saved = n_inuse + 1;
if (!(info->fetch.results.stacks = realloc(info->fetch.results.stacks, sizeof(void *) * n_saved)))
return -ENOMEM;
return -1;
}
memcpy(info->fetch.results.stacks, info->fetch.anchor, sizeof(void *) * n_inuse);
info->fetch.results.stacks[n_inuse] = NULL;
@ -755,14 +748,14 @@ static int slabinfo_stacks_reconfig_maybe (
int numitems)
{
if (slabinfo_items_check_failed(this, items, numitems))
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->numitems != numitems + 1
|| memcmp(this->items, items, sizeof(enum slabinfo_item) * numitems)) {
// allow for our SLABINFO_logical_end
if (!(this->items = realloc(this->items, sizeof(enum slabinfo_item) * (numitems + 1))))
return -ENOMEM;
return -1;
memcpy(this->items, items, sizeof(enum slabinfo_item) * numitems);
this->items[numitems] = SLABINFO_logical_end;
this->numitems = numitems + 1;
@ -790,11 +783,9 @@ PROCPS_EXPORT int procps_slabinfo_new (
struct slabinfo_info **info)
{
struct slabinfo_info *p;
int rc;
if (info == NULL)
if (info == NULL || *info != NULL)
return -EINVAL;
if (!(p = calloc(1, sizeof(struct slabinfo_info))))
return -ENOMEM;
@ -811,9 +802,9 @@ PROCPS_EXPORT int procps_slabinfo_new (
1) see if that caller's permissions were sufficient (root) |
2) make delta results potentially useful, even if 1st time |
3) elimnate need for history distortions 1st time 'switch' | */
if ((rc = slabinfo_read_failed(p))) {
if (slabinfo_read_failed(p)) {
procps_slabinfo_unref(&p);
return rc;
return -errno;
}
*info = p;
@ -841,6 +832,8 @@ PROCPS_EXPORT int procps_slabinfo_unref (
(*info)->refcount--;
if ((*info)->refcount < 1) {
int errno_sav = errno;
if ((*info)->slabinfo_fp) {
fclose((*info)->slabinfo_fp);
(*info)->slabinfo_fp = NULL;
@ -864,6 +857,8 @@ PROCPS_EXPORT int procps_slabinfo_unref (
free(*info);
*info = NULL;
errno = errno_sav;
return 0;
}
return (*info)->refcount;
@ -879,10 +874,12 @@ PROCPS_EXPORT struct slabinfo_result *procps_slabinfo_get (
static time_t sav_secs;
time_t cur_secs;
errno = EINVAL;
if (info == NULL)
return NULL;
if (item < 0 || item >= SLABINFO_logical_end)
return NULL;
errno = 0;
/* we will NOT read the slabinfo file with every call - rather, we'll offer
a granularity of 1 second between reads ... */
@ -894,9 +891,8 @@ PROCPS_EXPORT struct slabinfo_result *procps_slabinfo_get (
}
info->get_this.item = item;
// with 'get', we must NOT honor the usual 'noop' guarantee
// if (item > SLABINFO_noop)
info->get_this.result.ul_int = 0;
// with 'get', we must NOT honor the usual 'noop' guarantee
info->get_this.result.ul_int = 0;
Item_table[item].setsfunc(&info->get_this, &info->slabs, &info->nul_node);
return &info->get_this;
@ -915,18 +911,20 @@ PROCPS_EXPORT struct slabinfo_reap *procps_slabinfo_reap (
enum slabinfo_item *items,
int numitems)
{
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (0 > slabinfo_stacks_reconfig_maybe(&info->fetch_ext, items, numitems))
return NULL;
return NULL; // here, errno may be overridden with ENOMEM
errno = 0;
if (info->fetch_ext.dirty_stacks)
slabinfo_cleanup_stacks_all(&info->fetch_ext);
if (slabinfo_read_failed(info))
return NULL;
slabinfo_stacks_fetch(info);
if (0 > slabinfo_stacks_fetch(info))
return NULL;
info->fetch_ext.dirty_stacks = 1;
return &info->fetch.results;
@ -945,11 +943,12 @@ PROCPS_EXPORT struct slabinfo_stack *procps_slabinfo_select (
enum slabinfo_item *items,
int numitems)
{
errno = EINVAL;
if (info == NULL || items == NULL)
return NULL;
if (0 > slabinfo_stacks_reconfig_maybe(&info->select_ext, items, numitems))
return NULL;
return NULL; // here, errno may be overridden with ENOMEM
errno = 0;
if (!info->select_ext.extents
&& (!slabinfo_stacks_alloc(&info->select_ext, 1)))
@ -988,9 +987,9 @@ PROCPS_EXPORT struct slabinfo_stack **procps_slabinfo_sort (
struct sort_parms parms;
int offset;
errno = EINVAL;
if (info == NULL || stacks == NULL)
return NULL;
// a slabinfo_item is currently unsigned, but we'll protect our future
if (sortitem < 0 || sortitem >= SLABINFO_logical_end)
return NULL;
@ -1009,6 +1008,8 @@ PROCPS_EXPORT struct slabinfo_stack **procps_slabinfo_sort (
return NULL;
++p;
}
errno = 0;
parms.offset = offset;
parms.order = order;