cregit-Linux how code gets into the kernel

Release 4.14 arch/um/os-Linux/main.c

Directory: arch/um/os-Linux
/*
 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/resource.h>
#include <as-layout.h>
#include <init.h>
#include <kern_util.h>
#include <os.h>
#include <um_malloc.h>


#define PGD_BOUND (4 * 1024 * 1024)

#define STACKSIZE (8 * 1024 * 1024)

#define THREAD_NAME_LEN (256)


long elf_aux_hwcap;


static void set_stklim(void) { struct rlimit lim; if (getrlimit(RLIMIT_STACK, &lim) < 0) { perror("getrlimit"); exit(1); } if ((lim.rlim_cur == RLIM_INFINITY) || (lim.rlim_cur > STACKSIZE)) { lim.rlim_cur = STACKSIZE; if (setrlimit(RLIMIT_STACK, &lim) < 0) { perror("setrlimit"); exit(1); } } }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike86100.00%1100.00%
Total86100.00%1100.00%


static __init void do_uml_initcalls(void) { initcall_t *call; call = &__uml_initcall_start; while (call < &__uml_initcall_end) { (*call)(); call++; } }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike36100.00%1100.00%
Total36100.00%1100.00%


static void last_ditch_exit(int sig) { uml_cleanup(); exit(1); }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike17100.00%2100.00%
Total17100.00%2100.00%


static void install_fatal_handler(int sig) { struct sigaction action; /* All signals are enabled in this handler ... */ sigemptyset(&action.sa_mask); /* * ... including the signal being handled, plus we want the * handler reset to the default behavior, so that if an exit * handler is hanging for some reason, the UML will just die * after this signal is sent a second time. */ action.sa_flags = SA_RESETHAND | SA_NODEFER; action.sa_restorer = NULL; action.sa_handler = last_ditch_exit; if (sigaction(sig, &action, NULL) < 0) { os_warn("failed to install handler for signal %d " "- errno = %d\n", sig, errno); exit(1); } }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike6993.24%360.00%
Masami Hiramatsu34.05%120.00%
Américo Wang22.70%120.00%
Total74100.00%5100.00%

#define UML_LIB_PATH ":" OS_LIB_PATH "/uml"
static void setup_env_path(void) { char *new_path = NULL; char *old_path = NULL; int path_len = 0; old_path = getenv("PATH"); /* * if no PATH variable is set or it has an empty value * just use the default + /usr/lib/uml */ if (!old_path || (path_len = strlen(old_path)) == 0) { if (putenv("PATH=:/bin:/usr/bin/" UML_LIB_PATH)) perror("couldn't putenv"); return; } /* append /usr/lib/uml to the existing path */ path_len += strlen("PATH=" UML_LIB_PATH) + 1; new_path = malloc(path_len); if (!new_path) { perror("couldn't malloc to set a new PATH"); return; } snprintf(new_path, path_len, "PATH=%s" UML_LIB_PATH, old_path); if (putenv(new_path)) { perror("couldn't putenv to set a new PATH"); free(new_path); } }

Contributors

PersonTokensPropCommitsCommitProp
Mattia Dongili10481.89%133.33%
Américo Wang2217.32%133.33%
Jeff Dike10.79%133.33%
Total127100.00%3100.00%

extern void scan_elf_aux( char **envp);
int __init main(int argc, char **argv, char **envp) { char **new_argv; int ret, i, err; set_stklim(); setup_env_path(); setsid(); new_argv = malloc((argc + 1) * sizeof(char *)); if (new_argv == NULL) { perror("Mallocing argv"); exit(1); } for (i = 0; i < argc; i++) { new_argv[i] = strdup(argv[i]); if (new_argv[i] == NULL) { perror("Mallocing an arg"); exit(1); } } new_argv[argc] = NULL; /* * Allow these signals to bring down a UML if all other * methods of control fail. */ install_fatal_handler(SIGINT); install_fatal_handler(SIGTERM); #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA scan_elf_aux(envp); #endif do_uml_initcalls(); change_sig(SIGPIPE, 0); ret = linux_main(argc, argv); /* * Disable SIGPROF - I have no idea why libc doesn't do this or turn * off the profiling time, but UML dies with a SIGPROF just before * exiting when profiling is active. */ change_sig(SIGPROF, 0); /* * This signal stuff used to be in the reboot case. However, * sometimes a timer signal can come in when we're halting (reproducably * when writing out gcov information, presumably because that takes * some time) and cause a segfault. */ /* stop timers and set timer signal to be ignored */ os_timer_disable(); /* disable SIGIO for the fds and set SIGIO to be ignored */ err = deactivate_all_fds(); if (err) os_warn("deactivate_all_fds failed, errno = %d\n", -err); /* * Let any pending signals fire now. This ensures * that they won't be delivered after the exec, when * they are definitely not expected. */ unblock_signals(); os_info("\n"); /* Reboot */ if (ret) { execvp(new_argv[0], new_argv); perror("Failed to exec kernel"); ret = 1; } return uml_exitcode; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike20284.17%1055.56%
Paolo 'Blaisorblade' Giarrusso114.58%15.56%
Anton Ivanov104.17%211.11%
Richard Weinberger83.33%211.11%
Masami Hiramatsu62.50%211.11%
Mattia Dongili31.25%15.56%
Total240100.00%18100.00%

extern void *__real_malloc(int);
void *__wrap_malloc(int size) { void *ret; if (!kmalloc_ok) return __real_malloc(size); else if (size <= UM_KERN_PAGE_SIZE) /* finding contiguous pages can be hard*/ ret = uml_kmalloc(size, UM_GFP_KERNEL); else ret = vmalloc(size); /* * glibc people insist that if malloc fails, errno should be * set by malloc as well. So we do. */ if (ret == NULL) errno = ENOMEM; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Paolo 'Blaisorblade' Giarrusso3352.38%114.29%
Jeff Dike3047.62%685.71%
Total63100.00%7100.00%


void *__wrap_calloc(int n, int size) { void *ptr = __wrap_malloc(n * size); if (ptr == NULL) return NULL; memset(ptr, 0, n * size); return ptr; }

Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike46100.00%1100.00%
Total46100.00%1100.00%

extern void __real_free(void *); extern unsigned long high_physmem;
void __wrap_free(void *ptr) { unsigned long addr = (unsigned long) ptr; /* * We need to know how the allocation happened, so it can be correctly * freed. This is done by seeing what region of memory the pointer is * in - * physical memory - kmalloc/kfree * kernel virtual memory - vmalloc/vfree * anywhere else - malloc/free * If kmalloc is not yet possible, then either high_physmem and/or * end_vm are still 0 (as at startup), in which case we call free, or * we have set them, but anyway addr has not been allocated from those * areas. So, in both cases __real_free is called. * * CAN_KMALLOC is checked because it would be bad to free a buffer * with kmalloc/vmalloc after they have been turned off during * shutdown. * XXX: However, we sometimes shutdown CAN_KMALLOC temporarily, so * there is a possibility for memory leaks. */ if ((addr >= uml_physmem) && (addr < high_physmem)) { if (kmalloc_ok) kfree(ptr); } else if ((addr >= start_vm) && (addr < end_vm)) { if (kmalloc_ok) vfree(ptr); } else __real_free(ptr); }

Contributors

PersonTokensPropCommitsCommitProp
Paolo 'Blaisorblade' Giarrusso4355.84%120.00%
Jeff Dike3444.16%480.00%
Total77100.00%5100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Jeff Dike58368.35%1653.33%
Mattia Dongili11012.90%13.33%
Paolo 'Blaisorblade' Giarrusso9711.37%310.00%
Américo Wang242.81%13.33%
Richard Weinberger121.41%310.00%
Anton Ivanov111.29%26.67%
Masami Hiramatsu91.06%26.67%
Al Viro50.59%13.33%
Chris Wedgwood20.23%13.33%
Total853100.00%30100.00%
Directory: arch/um/os-Linux
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