diff options
Diffstat (limited to 'lib/libc')
| -rw-r--r-- | lib/libc/sys/ptrace.2 | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/lib/libc/sys/ptrace.2 b/lib/libc/sys/ptrace.2 index 807f907..8b61df3 100644 --- a/lib/libc/sys/ptrace.2 +++ b/lib/libc/sys/ptrace.2 @@ -28,6 +28,20 @@ to control another (the .Em traced process). +The tracing process must first attach to the traced process, and then +issue a series of +.Fn ptrace +system calls to control the execution of the process, as well as access +process memory and register state. +For the duration of the tracing session, the traced process will be +"re-parented", with its parent process id (and resulting behavior) +changed to the tracing process. +It is permissible for a tracing process to attach to more than one +other process at a time. +When the tracing process has completed its work, it must detach the +traced process; if a tracing process exits without first detaching all +processes it has attached, those processes will be killed. +.Pp Most of the time, the traced process runs normally, but when it receives a signal (see @@ -39,6 +53,16 @@ or the delivery of a .Dv SIGCHLD signal, examine the state of the stopped process, and cause it to terminate or continue as appropriate. +The signal may be a normal process signal, generated as a result of +traced process behavior, or use of the +.Xr kill 2 +system call; alternatively, it may be generated by the tracing facility +as a result of attaching, system calls, or stepping by the tracing +process. +The tracing process may choose to intercept the signal, using it to +observe process behavior (such as +.Dv SIGTRAP ), +or forward the signal to the process if appropriate. The .Fn ptrace system call |
