f5e8b4278
Denys Vlasenko
2017-11-02
Subject
init: reduce the window when init can lose reboot/poweroff signals
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init/init.c+8 -23
| @@ -1064,6 +1064,12 @@ int init_main(int argc UNUSED_PARAM, char **argv) | |
| #endif | |
| if (!DEBUG_INIT) { | |
| + | /* Some users send poweroff signals to init VERY early. |
| + | * To handle this, mask signals early, |
| + | * and unmask them only after signal handlers are installed. |
| + | */ |
| + | sigprocmask_allsigs(SIG_BLOCK); |
| + | |
| /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */ | |
| if (getpid() != 1 | |
| && (!ENABLE_LINUXRC || applet_name[0] != 'l') /* not linuxrc? */ | |
| @@ -1106,29 +1112,6 @@ int init_main(int argc UNUSED_PARAM, char **argv) | |
| message(L_CONSOLE | L_LOG, "init started: %s", bb_banner); | |
| #endif | |
| - | #if 0 |
| - | /* It's 2013, does anyone really still depend on this? */ |
| - | /* If you do, consider adding swapon to sysinit actions then! */ |
| - | /* struct sysinfo is linux-specific */ |
| - | # ifdef __linux__ |
| - | /* Make sure there is enough memory to do something useful. */ |
| - | /*if (ENABLE_SWAPONOFF) - WRONG: we may have non-bbox swapon*/ { |
| - | struct sysinfo info; |
| - | |
| - | if (sysinfo(&info) == 0 |
| - | && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024 |
| - | ) { |
| - | message(L_CONSOLE, "Low memory, forcing swapon"); |
| - | /* swapon -a requires /proc typically */ |
| - | new_init_action(SYSINIT, "mount -t proc proc /proc", ""); |
| - | /* Try to turn on swap */ |
| - | new_init_action(SYSINIT, "swapon -a", ""); |
| - | run_actions(SYSINIT); /* wait and removing */ |
| - | } |
| - | } |
| - | # endif |
| - | #endif |
| - | |
| /* Check if we are supposed to be in single user mode */ | |
| if (argv[1] | |
| && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1')) | |
| @@ -1204,6 +1187,8 @@ int init_main(int argc UNUSED_PARAM, char **argv) | |
| + (1 << SIGHUP) /* reread /etc/inittab */ | |
| #endif | |
| , record_signo); | |
| + | |
| + | sigprocmask_allsigs(SIG_UNBLOCK); |
| } | |
| /* Now run everything that needs to be run */ | |