Better debug logging of allocations and waitpit results

* strace.c (alloc_tcb): Print number of allocated tcb's if -d.
  (droptcb): Likewise.
  (handle_ptrace_event): Remove PTRACE_EVENT_EXEC debug message.
  (trace): Improve logging of waitpid: show WIFxxx, exitcode/signal,
  ptrace event name, WCOREDUMP - all on one line.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

diff --git a/strace.c b/strace.c
index c201316a7217c3e32529f728e81ff8513417f265..d6788d5de3904e69703773d72386a691df11d3ea 100644 (file)
--- a/strace.c
+++ b/strace.c
@@ -1200,6 +1200,8 @@ alloc_tcb(int pid, int command_options_parsed)
                        tcp->outf = outf; /* Initialise to current out file */
                        tcp->pfd = -1;
                        nprocs++;
+                       if (debug)
+                               fprintf(stderr, "new tcb for pid %d, active tcbs:%d\n", tcp->pid, nprocs);
                        if (command_options_parsed)
                                newoutf(tcp);
                        return tcp;
@@ -1554,6 +1556,8 @@ droptcb(struct tcb *tcp)
        }
 #endif
        nprocs--;
+       if (debug)
+               fprintf(stderr, "dropped tcb for pid %d, %d remain\n", tcp->pid, nprocs);
        tcp->pid = 0;
 
        if (tcp->parent != NULL) {
@@ -2322,8 +2326,6 @@ handle_ptrace_event(int status, struct tcb *tcp)
                return handle_new_child(tcp, childpid, 0);
        }
        if (status >> 16 == PTRACE_EVENT_EXEC) {
-               if (debug)
-                       fprintf(stderr, "PTRACE_EVENT_EXEC on pid %d (ignored)\n", tcp->pid);
                return 0;
        }
        /* Some PTRACE_EVENT_foo we didn't ask for?! */
@@ -2403,8 +2405,47 @@ trace()
                                popen_pid = 0;
                        continue;
                }
-               if (debug)
-                       fprintf(stderr, " [wait(%#x) = %u]\n", status, pid);
+               if (debug) {
+                       char buf[sizeof("WIFEXITED,exitcode=%u") + sizeof(int)*3 /*paranoia:*/ + 16];
+#ifdef LINUX
+                       unsigned ev = (unsigned)status >> 16;
+                       if (ev) {
+                               static const char *const event_names[] = {
+                                       [PTRACE_EVENT_CLONE] = "CLONE",
+                                       [PTRACE_EVENT_FORK]  = "FORK",
+                                       [PTRACE_EVENT_VFORK] = "VFORK",
+                                       [PTRACE_EVENT_VFORK_DONE] = "VFORK_DONE",
+                                       [PTRACE_EVENT_EXEC]  = "EXEC",
+                                       [PTRACE_EVENT_EXIT]  = "EXIT",
+                               };
+                               const char *e;
+                               if (ev < ARRAY_SIZE(event_names))
+                                       e = event_names[ev];
+                               else {
+                                       sprintf(buf, "?? (%u)", ev);
+                                       e = buf;
+                               }
+                               fprintf(stderr, " PTRACE_EVENT_%s", e);
+                       }
+#endif
+                       strcpy(buf, "???");
+                       if (WIFSIGNALED(status))
+#ifdef WCOREDUMP
+                               sprintf(buf, "WIFSIGNALED,%ssig=%s",
+                                               WCOREDUMP(status) ? "core," : "",
+                                               signame(WTERMSIG(status)));
+#else
+                               sprintf(buf, "WIFSIGNALED,sig=%s",
+                                               signame(WTERMSIG(status)));
+#endif
+                       if (WIFEXITED(status))
+                               sprintf(buf, "WIFEXITED,exitcode=%u", WEXITSTATUS(status));
+                       if (WIFSTOPPED(status))
+                               sprintf(buf, "WIFSTOPPED,sig=%s", signame(WSTOPSIG(status)));
+                       if (WIFCONTINUED(status))
+                               strcpy(buf, "WIFCONTINUED");
+                       fprintf(stderr, " [wait(0x%04x) = %u] %s\n", status, pid, buf);
+               }
 
                /* Look up `pid' in our table. */
                if ((tcp = pid2tcb(pid)) == NULL) {
@@ -2481,8 +2522,6 @@ Process %d attached (waiting for parent)\n",
                if (WIFEXITED(status)) {
                        if (pid == strace_child)
                                exit_code = WEXITSTATUS(status);
-                       if (debug)
-                               fprintf(stderr, "pid %u exited with %d\n", pid, WEXITSTATUS(status));
                        if ((tcp->flags & (TCB_ATTACHED|TCB_STARTUP)) == TCB_ATTACHED
 #ifdef TCB_GROUP_EXITING
                            && !(tcp->parent && (tcp->parent->flags & TCB_GROUP_EXITING))
@@ -2511,9 +2550,6 @@ Process %d attached (waiting for parent)\n",
                        droptcb(tcp);
                        continue;
                }
-               if (debug)
-                       fprintf(stderr, "pid %u stopped, [%s]\n",
-                               pid, signame(WSTOPSIG(status)));
 
                if (status >> 16) {
                        if (handle_ptrace_event(status, tcp) != 1)