1 /* 2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Licensed under the GPL 4 */ 5 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <unistd.h> 9 #include <errno.h> 10 #include <signal.h> 11 #include <string.h> 12 #include <termios.h> 13 #include <wait.h> 14 #include <sys/mman.h> 15 #include <sys/utsname.h> 16 #include <os.h> 17 18 void stack_protections(unsigned long address) 19 { 20 if (mprotect((void *) address, UM_THREAD_SIZE, 21 PROT_READ | PROT_WRITE | PROT_EXEC) < 0) 22 panic("protecting stack failed, errno = %d", errno); 23 } 24 25 int raw(int fd) 26 { 27 struct termios tt; 28 int err; 29 30 CATCH_EINTR(err = tcgetattr(fd, &tt)); 31 if (err < 0) 32 return -errno; 33 34 cfmakeraw(&tt); 35 36 CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt)); 37 if (err < 0) 38 return -errno; 39 40 /* 41 * XXX tcsetattr could have applied only some changes 42 * (and cfmakeraw() is a set of changes) 43 */ 44 return 0; 45 } 46 47 void setup_machinename(char *machine_out) 48 { 49 struct utsname host; 50 51 uname(&host); 52 #ifdef UML_CONFIG_UML_X86 53 # ifndef UML_CONFIG_64BIT 54 if (!strcmp(host.machine, "x86_64")) { 55 strcpy(machine_out, "i686"); 56 return; 57 } 58 # else 59 if (!strcmp(host.machine, "i686")) { 60 strcpy(machine_out, "x86_64"); 61 return; 62 } 63 # endif 64 #endif 65 strcpy(machine_out, host.machine); 66 } 67 68 void setup_hostinfo(char *buf, int len) 69 { 70 struct utsname host; 71 72 uname(&host); 73 snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename, 74 host.release, host.version, host.machine); 75 } 76 77 /* 78 * We cannot use glibc's abort(). It makes use of tgkill() which 79 * has no effect within UML's kernel threads. 80 * After that glibc would execute an invalid instruction to kill 81 * the calling process and UML crashes with SIGSEGV. 82 */ 83 static inline void __attribute__ ((noreturn)) uml_abort(void) 84 { 85 sigset_t sig; 86 87 fflush(NULL); 88 89 if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT)) 90 sigprocmask(SIG_UNBLOCK, &sig, 0); 91 92 for (;;) 93 if (kill(getpid(), SIGABRT) < 0) 94 exit(127); 95 } 96 97 void os_dump_core(void) 98 { 99 int pid; 100 101 signal(SIGSEGV, SIG_DFL); 102 103 /* 104 * We are about to SIGTERM this entire process group to ensure that 105 * nothing is around to run after the kernel exits. The 106 * kernel wants to abort, not die through SIGTERM, so we 107 * ignore it here. 108 */ 109 110 signal(SIGTERM, SIG_IGN); 111 kill(0, SIGTERM); 112 /* 113 * Most of the other processes associated with this UML are 114 * likely sTopped, so give them a SIGCONT so they see the 115 * SIGTERM. 116 */ 117 kill(0, SIGCONT); 118 119 /* 120 * Now, having sent signals to everyone but us, make sure they 121 * die by ptrace. Processes can survive what's been done to 122 * them so far - the mechanism I understand is receiving a 123 * SIGSEGV and segfaulting immediately upon return. There is 124 * always a SIGSEGV pending, and (I'm guessing) signals are 125 * processed in numeric order so the SIGTERM (signal 15 vs 126 * SIGSEGV being signal 11) is never handled. 127 * 128 * Run a waitpid loop until we get some kind of error. 129 * Hopefully, it's ECHILD, but there's not a lot we can do if 130 * it's something else. Tell os_kill_ptraced_process not to 131 * wait for the child to report its death because there's 132 * nothing reasonable to do if that fails. 133 */ 134 135 while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0) 136 os_kill_ptraced_process(pid, 0); 137 138 uml_abort(); 139 } 140 141 void um_early_printk(const char *s, unsigned int n) 142 { 143 printf("%.*s", n, s); 144 } 145