Avoid computing the number of bytes in shmall, by only
computing and printing the number of Kbytes. This avoids
some overflows, e.g.
$ echo "4503599627370496" > /proc/sys/kernel/shmall
$ ipcs -l | grep 'max total shared memory'
Before:
max total shared memory (kbytes) = 18014398509481980
After:
max total shared memory (kbytes) = 18014398509481984
$ echo "99993599627370500" > /proc/sys/kernel/shmall
99993599627370500
$ ipcs -l | grep 'max total shared memory'
Before:
max total shared memory (kbytes) = 18014398509481980
After:
max total shared memory (kbytes) = 399974398509482000
v1->v2:
Print the non-overflow KB value only for IPC_UNIT_KB and
IPC_UNIT_DEFAULT.
This way --bytes and --human options will still get an expected
output
(but not avoiding the overflow).
Signed-off-by: Vasilis Liaskovitis <vliaskovitis@xxxxxxxx>
---
sys-utils/ipcs.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/sys-utils/ipcs.c b/sys-utils/ipcs.c
index fc6fba4a6..d36cb1d2a 100644
--- a/sys-utils/ipcs.c
+++ b/sys-utils/ipcs.c
@@ -216,13 +216,19 @@ static void do_shm (char format, int unit)
ipc_print_size(unit == IPC_UNIT_DEFAULT ? IPC_UNIT_KB :
unit,
_("max seg size"), lim.shmmax, "\n", 0);
- tmp = (uint64_t) lim.shmall * pgsz;
- /* overflow handling, at least we don't print
ridiculous small values */
- if (lim.shmall != 0 && tmp / lim.shmall != pgsz) {
- tmp = UINT64_MAX - (UINT64_MAX % pgsz);
+ if (unit == IPC_UNIT_KB || unit == IPC_UNIT_DEFAULT) {
+ ipc_print_size(IPC_UNIT_DEFAULT,
+ _("max total shared memory (kbytes)"),
(pgsz / 1024) *
+ (uint64_t) lim.shmall, "\n", 0);
+ }
+ else {
+ tmp = (uint64_t) lim.shmall * pgsz;
+ /* overflow handling, at least we don't print
ridiculous small values */
+ if (lim.shmall != 0 && tmp / lim.shmall !=
pgsz) {
+ tmp = UINT64_MAX - (UINT64_MAX % pgsz);
+ }
+ ipc_print_size(unit, _("max total shared
memory"), tmp, "\n", 0);
}
- ipc_print_size(unit == IPC_UNIT_DEFAULT ? IPC_UNIT_KB :
unit,
- _("max total shared memory"), tmp, "\n",
0);
ipc_print_size(unit == IPC_UNIT_DEFAULT ?
IPC_UNIT_BYTES : unit,
_("min seg size"), lim.shmmin, "\n", 0);
return;
--
2.28.0
