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pstack
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Do not call perror in crawl() if no ptrace error 

* Set error_occured in crawl() whether an error occurs or not in one of
  the ptrace call of crawl().
* Call perror at end of crawl() only if error_occured is set.
This commit is contained in:
Thomas Preud'homme 2011-10-02 20:22:02 +02:00
parent b26e46a5ae
commit eb46b84ec3
1 changed files with 19 additions and 10 deletions
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29
pstack.c
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@ -643,19 +643,23 @@ static int crawl(int pid)
struct pt_regs regs;
errno = 0;
fp = -1;
ret = ptrace(PTRACE_GETREGS, pid, NULL, &regs);
if (ret != -1 && !errno) {
pc = PROGRAM_COUNTER(regs);
fp = FRAME_POINTER(regs);
}
else
error_occured = 1;
if ((pc != -1 && fp != -1) || !errno) {
if (!error_occured) {
print_pc(pc);
for ( ; !errno && fp; ) {
for ( ; !error_occured && fp; ) {
nextfp = ptrace(PTRACE_PEEKDATA, pid, NEXT_FRAME_POINTER_ADDR(fp), 0);
if (nextfp == (unsigned) -1 && errno) break;
if (nextfp == (unsigned) -1 && errno) {
error_occured = 1;
break;
}
nargs = NB_ARGS(fp, nextfp);
if (nargs > MAXARGS) nargs = MAXARGS;
@ -663,24 +667,29 @@ static int crawl(int pid)
fputs(" (", stdout);
for (i = 1; i <= nargs; i++) {
arg = ptrace(PTRACE_PEEKDATA, pid, ARG_NMBR(fp,i), 0);
if (arg == (unsigned) -1 && errno) break;
if (arg == (unsigned) -1 && errno) {
error_occured = 1;
break;
}
printf("%lx", arg);
if (i < nargs) fputs(", ", stdout);
}
fputc(')', stdout);
nargs = NB_ARGS_REMAINING(fp, nextfp, nargs);
if (!errno && nargs > 0) printf(" + %lx\n", nargs);
if (!error_occured && nargs > 0) printf(" + %lx\n", nargs);
else fputc('\n', stdout);
} else fputc('\n', stdout);
if (errno || !nextfp) break;
if (error_occured || !nextfp) break;
pc = ptrace(PTRACE_PEEKDATA, pid, NEXT_PROGRAM_COUNTER_ADDR(fp), 0);
if (pc == (unsigned) -1 && errno) break;
if (pc == (unsigned) -1 && errno) {
error_occured = 1;
break;
}
fp = nextfp;
print_pc(pc);
}
if (fp) error_occured = 1;
} else error_occured = 1;
}
if (error_occured) perror("crawl");
else errno = 0;