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Simplify expand_tcbtab and alloc_tcb

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Get rid of a few intermediate variables, simplifies a few expressions,
and uses error_msg_and_die instead of more verbose
fprintf+cleanup+exit sequence.
In alloc_tcp, I use memset to clear entire new tcp.
This not only saves a few bytes of code, but lowers the chances
of future bugs where some data "leaks out" into new tcb's
from old ones because we forgot to re-initialize it.

* strace.c (expand_tcbtab): Simplify this function. No logic changes.
  (alloc_tcb): Likewise.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko 2011-06-22 12:41:57 +02:00
parent e7c9024acf
commit 18da273675
1 changed files with 9 additions and 23 deletions
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32
strace.c
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@ -1252,21 +1252,15 @@ expand_tcbtab(void)
callers have pointers and it would be a pain.
So tcbtab is a table of pointers. Since we never
free the TCBs, we allocate a single chunk of many. */
struct tcb **newtab = (struct tcb **)
realloc(tcbtab, 2 * tcbtabsize * sizeof tcbtab[0]);
struct tcb *newtcbs = (struct tcb *) calloc(tcbtabsize,
sizeof *newtcbs);
int i;
if (newtab == NULL || newtcbs == NULL) {
fprintf(stderr, "%s: expand_tcbtab: out of memory\n",
progname);
cleanup();
exit(1);
}
for (i = tcbtabsize; i < 2 * tcbtabsize; ++i)
newtab[i] = &newtcbs[i - tcbtabsize];
int i = tcbtabsize;
struct tcb *newtcbs = calloc(tcbtabsize, sizeof(newtcbs[0]));
struct tcb **newtab = realloc(tcbtab, tcbtabsize * 2 * sizeof(tcbtab[0]));
if (newtab == NULL || newtcbs == NULL)
error_msg_and_die("expand_tcbtab: out of memory");
tcbtabsize *= 2;
tcbtab = newtab;
while (i < tcbtabsize)
tcbtab[i++] = newtcbs++;
}
struct tcb *
@ -1281,16 +1275,10 @@ alloc_tcb(int pid, int command_options_parsed)
for (i = 0; i < tcbtabsize; i++) {
tcp = tcbtab[i];
if ((tcp->flags & TCB_INUSE) == 0) {
memset(tcp, 0, sizeof(*tcp));
tcp->pid = pid;
tcp->parent = NULL;
#ifdef TCB_CLONE_THREAD
tcp->nclone_threads = 0;
#endif
tcp->flags = TCB_INUSE | TCB_STARTUP;
tcp->outf = outf; /* Initialise to current out file */
tcp->curcol = 0;
tcp->stime.tv_sec = 0;
tcp->stime.tv_usec = 0;
tcp->pfd = -1;
nprocs++;
if (command_options_parsed)
@ -1298,9 +1286,7 @@ alloc_tcb(int pid, int command_options_parsed)
return tcp;
}
}
fprintf(stderr, "%s: bug in alloc_tcb\n", progname);
cleanup();
exit(1);
error_msg_and_die("bug in alloc_tcb");
}
#ifdef USE_PROCFS