Restore the previous behavior as it's prefered.
This new behavior was introduced in 1.210.
Code should check for length of the result.
Requested by <mlelstv>
Swap the order of looking into zombie and all process lists, start now
with the zombie one. This prevents a race observed previously that the
same process could be detected on both lists during a single polling call.
While there:
- Short-circuit break for KERN_PROC_PID, once a pid has been detected.
- Removal of redundant "if (kbuf)" and "if (marker)" checks.
- Update of comments regarding potential optimization, explaining why we
don't want to it as of now. Performance gain from lookup call vs
iteration over a list is neglible on a regular system.
- Return ESRCH when no results have been found. This allows more easily
to implement a retry or abandon algorithm.
This corrects races observed in the existing ATF ptrace(2) tests, related
to await_zombie(). This function was expecting to check whether a process
has been transformed into a zombie, however it was causing occasional
crashes as it was overflowing the return buffer, returning the same pid
twice: once from allproc list and the second time from zombieproc one.
Fix suggested by <christos>
Short-circuit break suggested by <kre>
Discussed on tech-kern.
Sponsored by <The NetBSD Foundation>
That is, there was a comment "Ditto" - which once upon a time, was used
to indicate the the previous comment applied here as well. Time passed,
and software mutated, and the previous comment was unfortunately sacrificed.
Poor little Ditto was left all alone.
Noticed while doing some software archaeology.
typing 'cat /proc/aout_pid/auxv' on whatever a.out binary you're running.
Fortunately, amd64 does not enable EXEC_AOUT by default. Unfortunately,
i386 does enable it by default.
This means that the full executable path is always available.
- exec_elf.c: use p->path to set AT_SUN_EXECNAME, and since this is
always set, do so unconditionally.
- kern_exec.c: simplify pathexec, use kmem_strfree where appropriate
and set p->p_path
- kern_exit.c: free p->p_path
- kern_fork.c: set p->p_path for the child.
- kern_proc.c: use p->p_path to return the executable pathname; the
NULL check for p->p_path, should be a KASSERT?
- exec.h: gc ep_path, it is not used anymore
- param.h: bump version, 'struct proc' size change
TODO:
1. reference count the path string, to save copy at fork and free
just before exec?
2. canonicalize the pathname by changing namei() to LOCKPARENT
vnode and then using getcwd() on the parent directory?
This is a legacy interface from 4.4BSD, and it was
introduced to overcome shortcomings of ptrace(2) at that time, which are
no longer relevant (performance). Today /proc/#/ctl offers a narrow
subset of ptrace(2) commands and is not applicable for modern
applications use beyond simplistic tracing scenarios.
This removal will simplify kernel internals. Users will still be able to
use all the other /proc files.
This change won't affect other procfs files neither Linux compat
features within mount_procfs(8). /proc/#/ctl isn't available on Linux.
Remove:
- /proc/#/ctl from mount_procfs(8)
- P_FSTRACE note from the documentation of ps(1)
- /proc/#/ctl and filesystem tracing documentation from mount_procfs(8)
- KAUTH_REQ_PROCESS_PROCFS_CTL documentation from kauth(9)
- source code file miscfs/procfs/procfs_ctl.c
- PFSctl and procfs_doctl() from sys/miscfs/procfs/procfs.h
- KAUTH_REQ_PROCESS_PROCFS_CTL from sys/sys/kauth.h
- PSL_FSTRACE (0x00010000) from sys/sys/proc.h
- P_FSTRACE (0x00010000) from sys/sys/sysctl.h
Reduce code complexity after removal of this functionality.
Update TODO.ptrace accordingly: remove two entries about /proc tracing.
Do not keep legacy notes as comments in the headers about removed
PSL_FSTRACE / P_FSTRACE, as this interface had little number of users
(close or equal to zero).
Proposed on tech-kern@.
All filesystem tracing utility users are encouraged to switch to ptrace(2).
Sponsored by <The NetBSD Foundation>
various sysctl/procfs interfaces that allow it to be interrogated.
(This is rather than the temporary parent's pid when a process is
being traced and has been reparented.)
XXX The ppid in elf32 core files has not been similarly adjusted,
XXX Should it be ?
change anything, since kernel processes use the shared kernel map instead
of the one they are given here. For consistency though, it is better to
make sure UVM will not be tempted to access machine-dependent reserved
areas (e.g., the PTE space on x86).
mprotect settings so that debuggers can write to the text segment of traced
processes so that they can insert breakpoints. Turned off by default.
Ok: chuq (for now)
on context) into:
1. p_xexit: exit code
2. p_xsig: signal number
3. p_sflag & WCOREFLAG bit to indicated that the process core-dumped.
Fix the documentation of the flag bits in <sys/proc.h>
is a global sysctl kern.maxlwp to control this, which is by default 2048.
The first lwp of each process or kernel threads are not counted against the
limit. To show the current resource usage per user, I added a new sysctl
that dumps the uidinfo structure fields.
This value seems to never have been used anywhere.
This makes it consistent with it's cousin p_vm_msize (which is in pages as
well and has several uses).
version or the 32bit compat layout in execve1. Introduce a new function
copyin_psstrings for reading it back from userland and converting it to
the native layout. Refactor procfs to share most of the code with the
kern.proc_args sysctl handler.
This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.
- update the linux syscall table for each platform.
- support new-style (NPTL) linux pthreads on all platforms.
clone() with CLONE_THREAD uses 1 process with many LWPs
instead of separate processes.
- move the contents of sys__lwp_setprivate() into a new
lwp_setprivate() and use that everywhere.
- update linux_release[] and linux32_release[] to "2.6.18".
- adjust placement of emul fork/exec/exit hooks as needed
and adjust other emul code to match.
- convert all struct emul definitions to use named initializers.
- change the pid allocator to allow multiple pids to refer to the same proc.
- remove a few fields from struct proc that are no longer needed.
- disable the non-functional "vdso" code in linux32/amd64,
glibc works fine without it.
- fix a race in the futex code where we could miss a wakeup after
a requeue operation.
- redo futex locking to be a little more efficient.
Rename real routines to proc_find() and pgrp_find(), remove PFIND_* flags
and have consistent behaviour. Provide proc_find_raw() for special cases.
Fix memory leak in sysctl_proc_corename().
COMPAT_LINUX: rework ptrace() locking, minimise differences between
different versions per-arch.
Note: while this change adds some formal cosmetics for COMPAT_DARWIN and
COMPAT_IRIX - locking there is utterly broken (for ages).
Fixes PR/43176.
to it from kern_proc.c to kern_lwp.c. This makes kern_proc
"scheduling-clean" and more easily usable in environments with a
non-integrated scheduler (like, to take a random example, rump).
to the total free memory available to the system, use the smallest value
between VM_MAXUSER_ADDRESS and total free memory (having a RSS limit
bigger than VM_MAXUSER_ADDRESS has no real meaning).
Fix a possible int overflow when ptoa(uvmexp.free) is bigger than 4GB
with a 32 bits vaddr_t.
This change is similar to the one made in rev 1.144 of uvm/uvm_glue.c.
