diff options
Diffstat (limited to 'gdb/fork-child.c')
| -rw-r--r-- | gdb/fork-child.c | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/gdb/fork-child.c b/gdb/fork-child.c index aacd53c..0b14a94 100644 --- a/gdb/fork-child.c +++ b/gdb/fork-child.c @@ -379,131 +379,6 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env, #endif } -/* An inferior Unix process CHILD_PID has been created by a call to - fork() (or variants like vfork). It is presently stopped, and waiting - to be resumed. clone_and_follow_inferior will fork the debugger, - and that clone will "follow" (attach to) CHILD_PID. The original copy - of the debugger will not touch CHILD_PID again. - - Also, the original debugger will set FOLLOWED_CHILD FALSE, while the - clone will set it TRUE. - */ -void -clone_and_follow_inferior (int child_pid, int *followed_child) -{ - int debugger_pid; - int status; - char pid_spelling[100]; /* Arbitrary but sufficient length. */ - - /* This semaphore is used to coordinate the two debuggers' handoff - of CHILD_PID. The original debugger will detach from CHILD_PID, - and then the clone debugger will attach to it. (It must be done - this way because on some targets, only one process at a time can - trace another. Thus, the original debugger must relinquish its - tracing rights before the clone can pick them up.) - */ -#define SEM_TALK (1) -#define SEM_LISTEN (0) - int handoff_semaphore[2]; /* Original "talks" to [1], clone "listens" to [0] */ - int talk_value = 99; - int listen_value; - - /* Set debug_fork then attach to the child while it sleeps, to debug. */ - static int debug_fork = 0; - - /* It is generally good practice to flush any possible pending stdio - output prior to doing a fork, to avoid the possibility of both the - parent and child flushing the same data after the fork. */ - - gdb_flush (gdb_stdout); - gdb_flush (gdb_stderr); - - /* Open the semaphore pipes. - */ - status = pipe (handoff_semaphore); - if (status < 0) - error ("error getting pipe for handoff semaphore"); - - /* Clone the debugger. Note that the apparent call to vfork() - below *might* actually be a call to fork() due to the fact that - autoconf will ``#define vfork fork'' on certain platforms. */ - if (debug_fork) - debugger_pid = fork (); - else - debugger_pid = vfork (); - - if (debugger_pid < 0) - perror_with_name ("fork"); - - /* Are we the original debugger? If so, we must relinquish all claims - to CHILD_PID. */ - if (debugger_pid != 0) - { - char signal_spelling[100]; /* Arbitrary but sufficient length */ - - /* Detach from CHILD_PID. Deliver a "stop" signal when we do, though, - so that it remains stopped until the clone debugger can attach - to it. - */ - detach_breakpoints (child_pid); - - sprintf (signal_spelling, "%d", target_signal_to_host (TARGET_SIGNAL_STOP)); - target_require_detach (child_pid, signal_spelling, 1); - - /* Notify the clone debugger that it should attach to CHILD_PID. */ - write (handoff_semaphore[SEM_TALK], &talk_value, sizeof (talk_value)); - - *followed_child = 0; - } - - /* We're the child. */ - else - { - if (debug_fork) - sleep (debug_fork); - - /* The child (i.e., the cloned debugger) must now attach to - CHILD_PID. inferior_ptid is presently set to the parent process - of the fork, while CHILD_PID should be the child process of the - fork. - - Wait until the original debugger relinquishes control of CHILD_PID, - though. - */ - read (handoff_semaphore[SEM_LISTEN], &listen_value, sizeof (listen_value)); - - /* Note that we DON'T want to actually detach from inferior_ptid, - because that would allow it to run free. The original - debugger wants to retain control of the process. So, we - just reset inferior_ptid to CHILD_PID, and then ensure that all - breakpoints are really set in CHILD_PID. - */ - target_mourn_inferior (); - - /* Ask the tty subsystem to switch to the one we specified earlier - (or to share the current terminal, if none was specified). */ - - new_tty (); - - dont_repeat (); - sprintf (pid_spelling, "%d", child_pid); - target_require_attach (pid_spelling, 1); - - /* Perform any necessary cleanup, after attachment. (This form - of attaching can behave differently on some targets than the - standard method, where a process formerly not under debugger - control was suddenly attached to..) - */ - target_post_follow_inferior_by_clone (); - - *followed_child = 1; - } - - /* Discard the handoff sempahore. */ - (void) close (handoff_semaphore[SEM_LISTEN]); - (void) close (handoff_semaphore[SEM_TALK]); -} - /* Accept NTRAPS traps from the inferior. */ void |