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Do not allocate tiny cap_user_header/data structures, place them on stack.

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This allows us to avoid having code to malloc them, and code to check
for malloc failure. Resulting code decrease:
   text	   data	    bss	    dec	    hex	filename
  10175	      0	     16	  10191	   27cf	system.o.old
   9797	      0	      0	   9797	   2645	system.o

* system.c (sys_capget): Put cap_user_header_t and cap_user_data_t
  on stack, rather than allocating them in heap. These structures
  are very small (a few integer fields), stack is a better place
  for them.
  (sys_capset): Likewise.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko 2011-06-23 13:10:28 +02:00
parent cb2ad00652
commit b0bafbb5d1
1 changed files with 15 additions and 34 deletions
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49
system.c
View File

@ -1572,25 +1572,17 @@ static const struct xlat capabilities[] = {
int
sys_capget(struct tcb *tcp)
{
static cap_user_header_t arg0 = NULL;
static cap_user_data_t arg1 = NULL;
/* cap_user_ types are _pointers_ to (small) structs. */
/* Structs themselves have no names defined. */
/* Have to use ugly hack to place them on stack. */
cap_user_header_t arg0;
cap_user_data_t arg1;
long a0[sizeof(*arg0) / sizeof(long) + 1];
long a1[sizeof(*arg1) / sizeof(long) + 1];
arg0 = (cap_user_header_t*) &a0;
arg1 = (cap_user_data_t *) &a1;
if (!entering(tcp)) {
if (!arg0) {
if ((arg0 = malloc(sizeof(*arg0))) == NULL) {
fprintf(stderr, "out of memory\n");
tprintf("%#lx, %#lx", tcp->u_arg[0], tcp->u_arg[1]);
return -1;
}
}
if (!arg1) {
if ((arg1 = malloc(sizeof(*arg1))) == NULL) {
fprintf(stderr, "out of memory\n");
tprintf("%#lx, %#lx", tcp->u_arg[0], tcp->u_arg[1]);
return -1;
}
}
if (!tcp->u_arg[0])
tprintf("NULL");
else if (!verbose(tcp))
@ -1623,25 +1615,14 @@ sys_capget(struct tcb *tcp)
int
sys_capset(struct tcb *tcp)
{
static cap_user_header_t arg0 = NULL;
static cap_user_data_t arg1 = NULL;
cap_user_header_t arg0;
cap_user_data_t arg1;
long a0[sizeof(*arg0) / sizeof(long) + 1];
long a1[sizeof(*arg1) / sizeof(long) + 1];
arg0 = (cap_user_header_t*) &a0;
arg1 = (cap_user_data_t *) &a1;
if (entering(tcp)) {
if (!arg0) {
if ((arg0 = malloc(sizeof(*arg0))) == NULL) {
fprintf(stderr, "out of memory\n");
tprintf("%#lx, %#lx", tcp->u_arg[0], tcp->u_arg[1]);
return -1;
}
}
if (!arg1) {
if ((arg1 = malloc(sizeof(*arg1))) == NULL) {
fprintf(stderr, "out of memory\n");
tprintf("%#lx, %#lx", tcp->u_arg[0], tcp->u_arg[1]);
return -1;
}
}
if (!tcp->u_arg[0])
tprintf("NULL");
else if (!verbose(tcp))