Linux: add meter showing the current active user sessions #1364
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cgzones
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What re OpenBSD/NetBSD/Solaris?
@fraggerfox Can you help here?
I can check this out in the coming weekend and see if I can make the changes work in NetBSD. |
UserSessionsMeter.c
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| ret = updateViaUtmp(); | ||
| #else | ||
| ret = updateViaUtmp(); | ||
| #endif /* !BUILD_STATIC || HAVE_LIBSYSTEMD */ |
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- Can the systemd code depend only on
HAVE_LIBSYSTEMD? People who build htop without systemd support would likely not want the systemd code even when it's dynamically loaded and linked. - Code simplification suggestion:
int ret = -1; // Or maybe -ENOSYS for better diagnostic message
#if defined(HAVE_LIBSYSTEMD)
ret = update_via_sd_login();
#endif /* HAVE_LIBSYSTEMD */
if (ret < 0)
ret = updateViaUtmp();There was a problem hiding this comment.
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There is a systemd meter. Linking should be done accordingly as it's already done there.
-
This looks a bit cleaner, but has a dead store in
ret.
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Display the active user sessions either via systemd-logind or utmp. On Linux try to query systemd-login first, and otherwise count only the number of distinct sessions. On other platforms the number of unique sessions can not be determined and the number of all user entries are returned. Suggested in htop-dev#1363.
According to manual pages only OpenBSD does have not support for it. |
| if (!found) { | ||
| ret++; | ||
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| if (sessions_size +1 >= sessions_cap) { |
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| if (sessions_size +1 >= sessions_cap) { | |
| if (sessions_size + 1 >= sessions_cap) { |
| #ifndef BUILD_STATIC | ||
| #include <dlfcn.h> | ||
| #include "linux/Platform.h" | ||
| #endif |
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There should not be a platform-specific reference in the platform-independent code section.
| int ret; | ||
| #if (!defined(BUILD_STATIC) && defined(HTOP_LINUX)) || defined(HAVE_LIBSYSTEMD) | ||
| ret = update_via_sd_login(); | ||
| if (ret < 0) | ||
| ret = Generic_utmpx_get_users(); | ||
| #else | ||
| ret = Generic_utmpx_get_users(); | ||
| #endif /* (!BUILD_STATIC && HTOP_LINUX) || HAVE_LIBSYSTEMD */ | ||
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| users = ret; |
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Move this code into a platform-specific function. For everything aside from Linux this can be a direct forward to Generic_utmpx_get_users; on Linux that's mostly the above block of code.
| if (users >= 0) { | ||
| xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%d", ret); |
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Why distinguish here between ret and users?
| int len = xSnprintf(buffer, sizeof(buffer), "%d", users); | ||
| RichString_appendnAscii(out, CRT_colors[METER_VALUE], buffer, len); | ||
| } else { | ||
| RichString_appendAscii(out, CRT_colors[METER_VALUE], "N/A"); |
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Maybe shadow the value if not available?
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For meter text, I don't think shadowing is a good idea. IMHO.
| static void* libsystemd_handle; | ||
| static size_t libsystemd_loaded; | ||
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| void* Platform_load_libsystemd(void) { |
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I write some ideas just in case you are planning to refactor this further:
- The LibSystemd init code can become its own C files,
LibSystemd.candLibSystemd.h. Within it theLibSystemd_init()function would perform what you havePlatform_load_libsystemd()here. Look at the existinglinux/LibSensors.cfile for what I mean. Dynamically loaded libraries should have the init and unload functions like that. - When a libsystemd handle has been
dlopen'd, all the symbols htop requires should resolve all at once. No need to have theresolve()code in different places for the same library. - Make the resolved function pointers publicly assessible. That is, put these in
linux/LibSystemd.hwhen needed:
// In "linux/LibSystemd.h"
#ifdef BUILD_STATIC
#define sym_sd_bus_open_system sd_bus_open_system
#define sym_sd_bus_open_user sd_bus_open_user
#define sym_sd_bus_get_property_string sd_bus_get_property_string
#define sym_sd_bus_get_property_trivial sd_bus_get_prope
rty_trivial
#define sym_sd_bus_unref sd_bus_unref
#define sym_sd_get_sessions sd_get_sessions
#else
extern int (*sym_sd_bus_open_system)(sd_bus**);
extern int (*sym_sd_bus_open_user)(sd_bus**);
extern int (*sym_sd_bus_get_property_string)(sd_bus*, const char*, const char*, const char*, const char*, sd_bus_error*, char**);
extern int (*sym_sd_bus_get_property_trivial)(sd_bus*, const char*, const char*, const char*, const char*, sd_bus_error*, char, void*);
extern sd_bus* (*sym_sd_bus_unref)(sd_bus*);
extern int (*sym_sd_get_sessions)(char***);
#endif
cgzones
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Display the active user sessions either via systemd-logind or utmp.
Suggested in #1363.