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Attach to the target process before attempting to attach to its siblings

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* strace.c (attach_tcb): Attach to tcp->pid first.
This commit is contained in:
Дмитрий Левин 2016-07-25 18:48:50 +00:00
parent c9251518b0
commit 2ddb73ddd3
1 changed files with 46 additions and 67 deletions
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113
strace.c
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@ -1017,71 +1017,6 @@ process_opt_p_list(char *opt)
static void
attach_tcb(struct tcb *const tcp)
{
if (followfork && tcp->pid != strace_child) {
char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
sprintf(procdir, "/proc/%d/task", tcp->pid);
DIR *dir = opendir(procdir);
if (dir != NULL) {
unsigned int ntid = 0, nerr = 0;
struct_dirent *de;
while ((de = read_dir(dir)) != NULL) {
if (de->d_fileno == 0)
continue;
int tid = string_to_uint(de->d_name);
if (tid <= 0)
continue;
++ntid;
if (ptrace_attach_or_seize(tid) < 0) {
++nerr;
if (debug_flag)
perror_msg("attach: ptrace(%s, %d)",
ptrace_attach_cmd, tid);
continue;
}
if (debug_flag)
error_msg("attach to pid %d succeeded", tid);
struct tcb *tid_tcp =
(tid == tcp->pid) ? tcp : alloctcb(tid);
tid_tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
newoutf(tid_tcp);
}
closedir(dir);
ntid -= nerr;
if (ntid == 0) {
perror_msg("attach: ptrace(PTRACE_ATTACH, ...)");
droptcb(tcp);
return;
}
if (!qflag) {
if (ntid > 1)
error_msg("Process %u attached"
" with %u threads",
tcp->pid, ntid);
else
error_msg("Process %u attached",
tcp->pid);
}
if (!(tcp->flags & TCB_ATTACHED)) {
/* -p PID, we failed to attach to PID itself
* but did attach to some of its sibling threads.
* Drop PID's tcp.
*/
droptcb(tcp);
}
return;
} /* if (opendir worked) */
} /* if (-f) */
if (ptrace_attach_or_seize(tcp->pid) < 0) {
perror_msg("attach: ptrace(%s, %d)",
ptrace_attach_cmd, tcp->pid);
@ -1094,8 +1029,52 @@ attach_tcb(struct tcb *const tcp)
if (debug_flag)
error_msg("attach to pid %d (main) succeeded", tcp->pid);
if (!qflag)
error_msg("Process %u attached", tcp->pid);
char procdir[sizeof("/proc/%d/task") + sizeof(int) * 3];
DIR *dir;
unsigned int ntid = 0, nerr = 0;
if (followfork && tcp->pid != strace_child &&
sprintf(procdir, "/proc/%d/task", tcp->pid) > 0 &&
(dir = opendir(procdir)) != NULL) {
struct_dirent *de;
while ((de = read_dir(dir)) != NULL) {
if (de->d_fileno == 0)
continue;
int tid = string_to_uint(de->d_name);
if (tid <= 0 || tid == tcp->pid)
continue;
++ntid;
if (ptrace_attach_or_seize(tid) < 0) {
++nerr;
if (debug_flag)
perror_msg("attach: ptrace(%s, %d)",
ptrace_attach_cmd, tid);
continue;
}
if (debug_flag)
error_msg("attach to pid %d succeeded", tid);
struct tcb *tid_tcp = alloctcb(tid);
tid_tcp->flags |= TCB_ATTACHED | TCB_STARTUP |
post_attach_sigstop;
newoutf(tid_tcp);
}
closedir(dir);
}
if (!qflag) {
if (ntid > nerr)
error_msg("Process %u attached"
" with %u threads",
tcp->pid, ntid - nerr + 1);
else
error_msg("Process %u attached",
tcp->pid);
}
}
static void