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Improve error messages in detach()

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* strace.c (detach): Change return type from int to void.
Improve error meesages: show PID, tell exactly which operation fails.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko 2013-06-20 11:20:23 +02:00
parent 725dd425a6
commit 4a9ba989e6
1 changed files with 9 additions and 13 deletions
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22
strace.c
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@ -157,7 +157,7 @@ static const char *progname;
unsigned os_release; /* generated from uname()'s u.release */
static int detach(struct tcb *tcp);
static void detach(struct tcb *tcp);
static int trace(void);
static void cleanup(void);
static void interrupt(int sig);
@ -729,7 +729,7 @@ droptcb(struct tcb *tcp)
* attached-unstopped processes give the same ESRCH. For unattached process we
* would SIGSTOP it and wait for its SIGSTOP notification forever.
*/
static int
static void
detach(struct tcb *tcp)
{
int error;
@ -764,14 +764,14 @@ detach(struct tcb *tcp)
}
else if (errno != ESRCH) {
/* Shouldn't happen. */
perror_msg("detach: ptrace(PTRACE_DETACH, ...)");
perror_msg("detach: ptrace(%u,PTRACE_DETACH)", tcp->pid);
}
else
/* ESRCH: process is either not stopped or doesn't exist. */
if (my_tkill(tcp->pid, 0) < 0) {
if (errno != ESRCH)
/* Shouldn't happen. */
perror_msg("detach: checking sanity");
perror_msg("detach: tkill(%u,0)", tcp->pid);
/* else: process doesn't exist. */
}
else
@ -788,17 +788,15 @@ detach(struct tcb *tcp)
error = ptrace(PTRACE_INTERRUPT, tcp->pid, 0, 0);
if (!error)
interrupt_done = 1;
else if (errno != ESRCH)
perror_msg("detach: ptrace(%u,PTRACE_INTERRUPT)", tcp->pid);
}
else {
error = my_tkill(tcp->pid, SIGSTOP);
if (!error)
sigstop_expected = 1;
}
if (error && errno != ESRCH) {
if (use_seize)
perror_msg("detach: ptrace(PTRACE_INTERRUPT, ...)");
else
perror_msg("detach: stopping child");
else if (errno != ESRCH)
perror_msg("detach: tkill(%u,SIGSTOP)", tcp->pid);
}
}
}
@ -811,7 +809,7 @@ detach(struct tcb *tcp)
continue;
if (errno == ECHILD) /* Already gone. */
break;
perror_msg("detach: waiting");
perror_msg("detach: waitpid(%u)", tcp->pid);
break;
}
if (!WIFSTOPPED(status)) {
@ -870,8 +868,6 @@ detach(struct tcb *tcp)
fprintf(stderr, "Process %u detached\n", tcp->pid);
droptcb(tcp);
return error;
}
static void