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.
36c350f07c
Note: this is by far the most important and complex patch of the whole
series, please review it carefully; thank you very much!
For this patch, we decided to keep the original function's design and
skeleton, to avoid regressions and behavior changes, while fixing the
various bugs and overflows. And like the "Harden file2str()" patch, this
patch does not fail when about to overflow, but truncates instead: there
is information available about this process, so return it to the caller;
also, we used INT_MAX as a limit, but a lower limit could be used.
The easy changes:
- Replace sprintf() with snprintf() (and check for truncation).
- Replace "if (n == 0 && rbuf == 0)" with "if (n <= 0 && tot <= 0)" and
do break instead of return: it simplifies the code (only one place to
handle errors), and also guarantees that in the while loop either n or
tot is > 0 (or both), even if n is reset to 0 when about to overflow.
- Remove the "if (n < 0)" block in the while loop: it is (and was) dead
code, since we enter the while loop only if n >= 0.
- Rewrite the missing-null-terminator detection: in the original
function, if the size of the file is a multiple of 2047, a null-
terminator is appended even if the file is already null-terminated.
- Replace "if (n <= 0 && !end_of_file)" with "if (n < 0 || tot <= 0)":
originally, it was equivalent to "if (n < 0)", but we added "tot <= 0"
to handle the first break of the while loop, and to guarantee that in
the rest of the function tot is > 0.
- Double-force ("belt and suspenders") the null-termination of rbuf:
this is (and was) essential to the correctness of the function.
- Replace the final "while" loop with a "for" loop that behaves just
like the preceding "for" loop: in the original function, this would
lead to unexpected results (for example, if rbuf is |\0|A|\0|, this
would return the array {"",NULL} but should return {"","A",NULL}; and
if rbuf is |A|\0|B| (should never happen because rbuf should be null-
terminated), this would make room for two pointers in ret, but would
write three pointers to ret).
The hard changes:
- Prevent the integer overflow of tot in the while loop, but unlike
file2str(), file2strvec() cannot let tot grow until it almost reaches
INT_MAX, because it needs more space for the pointers: this is why we
introduced ARG_LEN, which also guarantees that we can add "align" and
a few sizeof(char*)s to tot without overflowing.
- Prevent the integer overflow of "tot + c + align": when INT_MAX is
(almost) reached, we write the maximal safe amount of pointers to ret
(ARG_LEN guarantees that there is always space for *ret = rbuf and the
NULL terminator).
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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.