分类: C/C++
2006-09-19 21:52:47
1 dummy_function (void) 2 { 3 unsigned char *ptr = 0x00; 4 *ptr = 0x00; 5 } 6 7 int main (void) 8 { 9 dummy_function (); 10 11 return 0; 12 } |
xiaosuo@gentux test $ ./a.out 段错误 |
xiaosuo@gentux test $ gcc -g -rdynamic d.c xiaosuo@gentux test $ gdb ./a.out GNU gdb 6.5 Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1". (gdb) r Starting program: /home/xiaosuo/test/a.out Program received signal SIGSEGV, Segmentation fault. 0x08048524 in dummy_function () at d.c:4 4 *ptr = 0x00; (gdb) |
The default action of certain signals is to cause a process to terminate and produce a core dump file, a disk file containing an image of the process's memory at the time of termination. A list of the signals which cause a process to dump core can be found in signal(7). |
xiaosuo@gentux test $ ulimit -c 0 xiaosuo@gentux test $ ulimit -c 1000 xiaosuo@gentux test $ ulimit -c 1000 xiaosuo@gentux test $ ./a.out 段错误 (core dumped) xiaosuo@gentux test $ ls a.out core d.c f.c g.c pango.c test_iconv.c test_regex.c |
xiaosuo@gentux test $ gdb ./a.out core GNU gdb 6.5 Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1". warning: Can't read pathname for load map: 输入/输出错误. Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/ld-linux.so.2...done. Loaded symbols for /lib/ld-linux.so.2 Core was generated by `./a.out'. Program terminated with signal 11, Segmentation fault. #0 0x08048524 in dummy_function () at d.c:4 4 *ptr = 0x00; |
#include #include #include #include void dump(int signo) { char buf[1024]; char cmd[1024]; FILE *fh; snprintf(buf, sizeof(buf), "/proc/%d/cmdline", getpid()); if(!(fh = fopen(buf, "r"))) exit(0); if(!fgets(buf, sizeof(buf), fh)) exit(0); fclose(fh); if(buf[strlen(buf) - 1] == '\n') buf[strlen(buf) - 1] = '\0'; snprintf(cmd, sizeof(cmd), "gdb %s %d", buf, getpid()); system(cmd); exit(0); } void dummy_function (void) { unsigned char *ptr = 0x00; *ptr = 0x00; } int main (void) { signal(SIGSEGV, &dump); dummy_function (); return 0; } |
xiaosuo@gentux test $ gcc -g -rdynamic f.c xiaosuo@gentux test $ ./a.out GNU gdb 6.5 Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1". Attaching to program: /home/xiaosuo/test/a.out, process 9563 Reading symbols from /lib/libc.so.6...done. Loaded symbols for /lib/libc.so.6 Reading symbols from /lib/ld-linux.so.2...done. Loaded symbols for /lib/ld-linux.so.2 0xffffe410 in __kernel_vsyscall () (gdb) bt #0 0xffffe410 in __kernel_vsyscall () #1 0xb7ee4b53 in waitpid () from /lib/libc.so.6 #2 0xb7e925c9 in strtold_l () from /lib/libc.so.6 #3 0x08048830 in dump (signo=11) at f.c:22 #4 #5 0x0804884c in dummy_function () at f.c:31 #6 0x08048886 in main () at f.c:38 |
#include #include #include #include /* A dummy function to make the backtrace more interesting. */ void dummy_function (void) { unsigned char *ptr = 0x00; *ptr = 0x00; } void dump(int signo) { void *array[10]; size_t size; char **strings; size_t i; size = backtrace (array, 10); strings = backtrace_symbols (array, size); printf ("Obtained %zd stack frames.\n", size); for (i = 0; i < size; i++) printf ("%s\n", strings[i]); free (strings); exit(0); } int main (void) { signal(SIGSEGV, &dump); dummy_function (); return 0; } |
xiaosuo@gentux test $ gcc -g -rdynamic g.c xiaosuo@gentux test $ ./a.out Obtained 5 stack frames. ./a.out(dump+0x19) [0x80486c2] [0xffffe420] ./a.out(main+0x35) [0x804876f] /lib/libc.so.6(__libc_start_main+0xe6) [0xb7e02866] ./a.out [0x8048601] |
xiaosuo@gentux test $ objdump -d a.out |
8048765: e8 02 fe ff ff call 804856c 804876a: e8 25 ff ff ff call 8048694 804876f: b8 00 00 00 00 mov $0x0,%eax 8048774: c9 leave |