dd3aa1224a
This is a popular, low-level function. Let's use NMStrBuf.
Also, Coverity wrongly things that there is a leak here. This change
should also avoid that:
Error: RESOURCE_LEAK (CWE-772):
NetworkManager-1.31.3/src/core/settings/plugins/ifcfg-rh/shvar.c:411: alloc_arg: "_gstr_init" allocates memory that is stored into "str".
NetworkManager-1.31.3/src/core/settings/plugins/ifcfg-rh/shvar.c:423: noescape: Resource "str" is not freed or pointed-to in "g_string_append_len".
NetworkManager-1.31.3/src/core/settings/plugins/ifcfg-rh/shvar.c:619: leaked_storage: Variable "str" going out of scope leaks the storage it points to.
# 617| nm_assert(!str);
# 618| *to_free = NULL;
# 619|-> return "";
# 620| }
# 621|
Profile:
We run test-ifcfg-rh which calls svUnescape() under realistic circumstances.
However, the test does too many other things that svUnescape() would be
measurable. So use the following patch, to run the tested code more frequently:
diff --git a/src/core/settings/plugins/ifcfg-rh/shvar.c b/src/core/settings/plugins/ifcfg-rh/shvar.c
index c6099dd1731c..18a907113ea9 100644
--- a/src/core/settings/plugins/ifcfg-rh/shvar.c
+++ b/src/core/settings/plugins/ifcfg-rh/shvar.c
@@ -645,6 +645,24 @@ out_error:
return NULL;
}
+#define svUnescape(value, to_free) \
+ ({ \
+ const char *_value = (value); \
+ const char *_result; \
+ int _i; \
+ \
+ for (_i = 0; TRUE; _i++) { \
+ gs_free char *_to_free; \
+ \
+ _result = svUnescape(_value, &_to_free); \
+ if (_i < 1000) \
+ continue; \
+ *(to_free) = g_steal_pointer(&_to_free); \
+ break; \
+ } \
+ _result; \
+ })
+
/*****************************************************************************/
shvarFile *
Build:
CFLAGS='-O2' ./autogen.sh --with-more-asserts=0
make -j 10 src/core/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh && \
src/core/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh &&
perf stat -r 50 -B src/core/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh
Before:
Performance counter stats for 'src/core/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh' (20 runs):
590.56 msec task-clock:u # 0.972 CPUs utilized ( +- 0.48% )
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
1,091 page-faults:u # 0.002 M/sec ( +- 0.12% )
2,022,618,453 cycles:u # 3.425 GHz ( +- 0.33% )
4,165,011,633 instructions:u # 2.06 insn per cycle ( +- 0.01% )
1,168,673,648 branches:u # 1978.910 M/sec ( +- 0.01% )
8,279,364 branch-misses:u # 0.71% of all branches ( +- 0.14% )
0.60739 +- 0.00292 seconds time elapsed ( +- 0.48% )
After:
Performance counter stats for 'src/core/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh' (50 runs):
580.19 msec task-clock:u # 0.972 CPUs utilized ( +- 0.33% )
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
1,092 page-faults:u # 0.002 M/sec ( +- 0.08% )
1,956,368,933 cycles:u # 3.372 GHz ( +- 0.22% )
4,106,984,148 instructions:u # 2.10 insn per cycle ( +- 0.01% )
1,087,931,864 branches:u # 1875.143 M/sec ( +- 0.01% )
7,731,041 branch-misses:u # 0.71% of all branches ( +- 0.15% )
0.59680 +- 0.00193 seconds time elapsed ( +- 0.32% )
The run time varies greatly. But it can be seen that the new code is consistently
faster.
****************** NetworkManager core daemon has moved to gitlab.freedesktop.org! git clone https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git ****************** Networking that Just Works -------------------------- NetworkManager attempts to keep an active network connection available at all times. The point of NetworkManager is to make networking configuration and setup as painless and automatic as possible. NetworkManager is intended to replace default route, replace other routes, set IP addresses, and in general configure networking as NM sees fit (with the possibility of manual override as necessary). In effect, the goal of NetworkManager is to make networking Just Work with a minimum of user hassle, but still allow customization and a high level of manual network control. If you have special needs, we'd like to hear about them, but understand that NetworkManager is not intended for every use-case. NetworkManager will attempt to keep every network device in the system up and active, as long as the device is available for use (has a cable plugged in, the killswitch isn't turned on, etc). Network connections can be set to 'autoconnect', meaning that NetworkManager will make that connection active whenever it and the hardware is available. "Settings services" store lists of user- or administrator-defined "connections", which contain all the settings and parameters required to connect to a specific network. NetworkManager will _never_ activate a connection that is not in this list, or that the user has not directed NetworkManager to connect to. How it works: The NetworkManager daemon runs as a privileged service (since it must access and control hardware), but provides a D-Bus interface on the system bus to allow for fine-grained control of networking. NetworkManager does not store connections or settings, it is only the mechanism by which those connections are selected and activated. To store pre-defined network connections, two separate services, the "system settings service" and the "user settings service" store connection information and provide these to NetworkManager, also via D-Bus. Each settings service can determine how and where it persistently stores the connection information; for example, the GNOME applet stores its configuration in GConf, and the system settings service stores its config in distro-specific formats, or in a distro- agnostic format, depending on user/administrator preference. A variety of other system services are used by NetworkManager to provide network functionality: wpa_supplicant for wireless connections and 802.1x wired connections, pppd for PPP and mobile broadband connections, DHCP clients for dynamic IP addressing, dnsmasq for proxy nameserver and DHCP server functionality for internet connection sharing, and avahi-autoipd for IPv4 link-local addresses. Most communication with these daemons occurs, again, via D-Bus. Why doesn't my network Just Work? Driver problems are the #1 cause of why NetworkManager sometimes fails to connect to wireless networks. Often, the driver simply doesn't behave in a consistent manner, or is just plain buggy. NetworkManager supports _only_ those drivers that are shipped with the upstream Linux kernel, because only those drivers can be easily fixed and debugged. ndiswrapper, vendor binary drivers, or other out-of-tree drivers may or may not work well with NetworkManager, precisely because they have not been vetted and improved by the open-source community, and because problems in these drivers usually cannot be fixed. Sometimes, command-line tools like 'iwconfig' will work, but NetworkManager will fail. This is again often due to buggy drivers, because these drivers simply aren't expecting the dynamic requests that NetworkManager and wpa_supplicant make. Driver bugs should be filed in the bug tracker of the distribution being run, since often distributions customize their kernel and drivers. Sometimes, it really is NetworkManager's fault. If you think that's the case, please file a bug at: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues Attaching NetworkManager debug logs from the journal (or wherever your distribution directs syslog's 'daemon' facility output, as /var/log/messages or /var/log/daemon.log) is often very helpful, and (if you can get) a working wpa_supplicant config file helps enormously. See the logging section of file contrib/fedora/rpm/NetworkManager.conf for how to enable debug logging in NetworkManager.