Command line and full screen utilities for browsing procfs, a "pseudo" file system dynamically generated by Linux to provide information about the status of entries in its process table.
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readeither() caches (in new_p) a pointer to the proc_t of a task-group leader, but readeither()'s callers can do pretty much anything with the proc_t structure passed to and/or returned by this function. For example, they can 1/ free it or 2/ recycle it (by passing it to readeither() as x). 1/ leads to a use-after-free, and 2/ leads to unexpected behavior when taskreader()/simple_readtask() is called with new_p equal to x (this is not a theoretical flaw: 2/ happens in readproctab3() when want_task() returns false and p is a group leader). As a workaround, we keep a copy of new_p's first member (tid) in static storage, and the next times we enter readeither() we check this "canary" against the tid in new_p: if they differ, we reset new_p to NULL, which forces the allocation of a new proc_t (the new "leader", or reference). This always detects 2/ (because free_acquired(x,1) memsets x and hence new_p); always detects 1/ if freed via free_acquired() and/or freeproc() (very likely, otherwise memory may be leaked); probably detects 1/ even if freed directly via free() (because the canary is the first member of proc_t, likely to be overwritten by free()); but can not detect 1/ if free() does not write to new_p's chunk at all. Moreover, accessing new_p->tid to check the canary in case 1/ is itself a use-after-free, so a better long-term solution should be implemented at some point (we wanted to avoid intrusive and backward-incompatible changes in this library function, hence this imperfect workaround). |
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|---|---|---|
| contrib | ||
| Documentation | ||
| include | ||
| lib | ||
| man-po | ||
| misc | ||
| po | ||
| proc | ||
| ps | ||
| testsuite | ||
| top | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| AUTHORS | ||
| autogen.sh | ||
| ChangeLog | ||
| configure.ac | ||
| COPYING | ||
| COPYING.LIB | ||
| create-man-pot.sh | ||
| free.1 | ||
| free.c | ||
| INSTALL.md | ||
| kill.1 | ||
| Makefile.am | ||
| NEWS | ||
| pgrep.1 | ||
| pgrep.c | ||
| pidof.1 | ||
| pidof.c | ||
| pkill.1 | ||
| pmap.1 | ||
| pmap.c | ||
| procio.c | ||
| pwdx.1 | ||
| pwdx.c | ||
| README.md | ||
| skill.1 | ||
| skill.c | ||
| slabtop.1 | ||
| slabtop.c | ||
| snice.1 | ||
| sysctl.8 | ||
| sysctl.c | ||
| sysctl.conf | ||
| sysctl.conf.5 | ||
| tload.1 | ||
| tload.c | ||
| translate-man.sh | ||
| uptime.1 | ||
| uptime.c | ||
| vmstat.8 | ||
| vmstat.c | ||
| w.1 | ||
| w.c | ||
| watch.1 | ||
| watch.c | ||
procps
procps is a set of command line and full-screen utilities that provide information out of the pseudo-filesystem most commonly located at /proc. This filesystem provides a simple interface to the kernel data structures. The programs of procps generally concentrate on the structures that describe the processess running on the system.
The following programs are found in procps:
- free - Report the amount of free and used memory in the system
- kill - Send a signal to a process based on PID
- pgrep - List processes based on name or other attributes
- pkill - Send a signal to a process based on name or other attributes
- pmap - Report memory map of a process
- ps - Report information of processes
- pwdx - Report current directory of a process
- skill - Obsolete version of pgrep/pkill
- slabtop - Display kernel slab cache information in real time
- snice - Renice a process
- sysctl - Read or Write kernel parameters at run-time
- tload - Graphical representation of system load average
- top - Dynamic real-time view of running processes
- uptime - Display how long the system has been running
- vmstat - Report virtual memory statistics
- w - Report logged in users and what they are doing
- watch - Execute a program periodically, showing output fullscreen
Reporting Bugs
There are a few ways of reporting bugs or feature requests:
- Your distributions bug reporter. If you are using a distribution your first port of call is their bug tracker. This is because each distribution has their own patches and way of dealing with bugs. Also bug reporting often does not need any subscription to websites.
- GitLab Issues - To the left of this page is the issue tracker. You can report bugs here.
- Email list - We have an email list (see below) where you can report bugs. The problem with this method is bug reports often get lost and cannot be tracked. This is especially a big problem when its something that will take time to resolve.
If you need to report bugs, there is more details on the Bug Reporting page.
Email List
The email list for the developers and users of procps is found at http://www.freelists.org/archive/procps/ This email list discusses the development of procps and is used by distributions to also forward or discuss bugs.