Changes between Version 3 and Version 4 of Dev/KernelHack/COINS/worklog/201111

Timestamp:

Nov 11, 2011 2:22:57 PM (14 years ago)

Author:

mitty

Comment:

--

Dev/KernelHack/COINS/worklog/201111

@@ -1207 +1207 @@
 new_debug with argv[i]: Invalid argument
 }}}
+
+ = 11/09 =
+ == change sys_clock_gettime to getnstimeofday ==
+ * http://hira-consulting.com/wiki/index.php?getnstimeofday%28%29%2Flinux2.6
+
+ * vim arch/x86/kernel/new_debug.c
+{{{#!diff
+Index: arch/x86/kernel/new_debug.c
+===================================================================
+--- arch/x86/kernel/new_debug.c (リビジョン 1390)
++++ arch/x86/kernel/new_debug.c (作業コピー)
+@@ -35,7 +35,7 @@
+         printk(KERN_DEBUG "%s\n", message);
+         
+         if (tp_user != NULL) {
+-                sys_clock_gettime(CLOCK_REALTIME, &ts);
++                getnstimeofday(&ts);
+                 if (copy_to_user(tp_user, &ts, sizeof(ts)) != 0) {
+                         errno = -EFAULT;
+                         goto out;
+}}}
+
+ * windell46:i386 s0711489$ ./build
+{{{
+Kernel: arch/x86/boot/bzImage is ready  (#12)
+}}}
+ * s0711489@ubuntu-lucid:~$ sudo /mnt/hgfs/tools/install.sh
+
+
+ * gdb
+{{{
+(gdb) file vmlinux
+Reading symbols from /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/i386/vmlinux...(no debugging symbols found)...done.
+(gdb) b sys_new_debug
+Breakpoint 1 at 0xc101d89c: file arch/x86/kernel/new_debug.c, line 9.
+(gdb) target remote windell46:8832
+Remote debugging using windell46:8832
+0xc1007cdf in native_safe_halt ()
+    at /home/ugrad/07/s0711489/coursework/KernelHack/linux-2.6.35.14/i386/arch/x86/include/asm/irqflags.h:49
+49              asm volatile("sti; hlt": : :"memory");
+(gdb) c
+Continuing.
+
+Breakpoint 1, sys_new_debug (message_user=0x8048646 "new_debug()", tp_user=0x0)
+    at arch/x86/kernel/new_debug.c:9
+9       SYSCALL_DEFINE2(new_debug, const char *, message_user, struct timespec*, tp_user) {
+(gdb) l
+4       #include <linux/time.h>
+5
+6       /* from kernel/printk.c */
+7       #define __LOG_BUF_LEN 1024
+8
+9       SYSCALL_DEFINE2(new_debug, const char *, message_user, struct timespec*, tp_user) {
+10              int errno;
+11              static char message[__LOG_BUF_LEN];
+12              struct timespec ts;
+13              long len = 0;
+(gdb)
+14
+15              if(tp_user != NULL && ! access_ok(VERIFY_WRITE, tp_user, sizeof(*tp_user)) ) {
+16                      errno = -EFAULT;
+17                      goto out;
+18              }
+19
+20              if (message_user == NULL) {
+21                      errno = -EINVAL;
+22                      goto out;
+23              }
+(gdb)
+24              len = strnlen_user(message_user, __LOG_BUF_LEN);
+25              if (len == 0 || len > __LOG_BUF_LEN) {
+26                      errno = -EINVAL;
+27                      goto out;
+28              }
+29              if (strncpy_from_user(message, message_user, sizeof(message) - 1) < 0) {
+30                      errno = -EFAULT;
+31                      goto out;
+32              }
+33              message[sizeof(message) - 1] = '\0';
+(gdb)
+34
+35              printk(KERN_DEBUG "%s\n", message);
+36
+37              if (tp_user != NULL) {
+38                      getnstimeofday(&ts);
+39                      if (copy_to_user(tp_user, &ts, sizeof(ts)) != 0) {
+40                              errno = -EFAULT;
+41                              goto out;
+42                      }
+43              }
+(gdb)
+44
+45              errno = 0;
+46
+47      out:
+48              return errno;
+49      }
+(gdb) s
+15              if(tp_user != NULL && ! access_ok(VERIFY_WRITE, tp_user, sizeof(*tp_user)) ) {
+(gdb)
+20              if (message_user == NULL) {
+(gdb)
+24              len = strnlen_user(message_user, __LOG_BUF_LEN);
+(gdb)
+strnlen_user (s=0x8048646 "new_debug()", n=1024)
+    at arch/x86/lib/usercopy_32.c:196
+196     {
+(gdb) finish
+Run till exit from #0  strnlen_user (s=0x8048646 "new_debug()", n=1024)
+    at arch/x86/lib/usercopy_32.c:196
+sys_new_debug (message_user=0x8048646 "new_debug()", tp_user=0x0)
+    at arch/x86/kernel/new_debug.c:25
+25              if (len == 0 || len > __LOG_BUF_LEN) {
+Value returned is $1 = 12
+(gdb) s
+29              if (strncpy_from_user(message, message_user, sizeof(message) - 1) < 0) {
+(gdb)
+strncpy_from_user (dst=0xc158da00 "", src=0x8048646 "new_debug()", count=1023)
+    at arch/x86/lib/usercopy_32.c:114
+114     {
+(gdb) finish
+Run till exit from #0  strncpy_from_user (dst=0xc158da00 "",
+    src=0x8048646 "new_debug()", count=1023) at arch/x86/lib/usercopy_32.c:114
+0xc101d8ea in sys_new_debug (message_user=0x8048646 "new_debug()", tp_user=0x0)
+    at arch/x86/kernel/new_debug.c:29
+29              if (strncpy_from_user(message, message_user, sizeof(message) - 1) < 0) {
+Value returned is $2 = 11
+(gdb) s
+35              printk(KERN_DEBUG "%s\n", message);
+(gdb)
+33              message[sizeof(message) - 1] = '\0';
+(gdb)
+35              printk(KERN_DEBUG "%s\n", message);
+(gdb)
+printk (fmt=0xc1449542 "<7>%s\n") at kernel/printk.c:614
+614             va_start(args, fmt);
+(gdb) finish
+Run till exit from #0  printk (fmt=0xc1449542 "<7>%s\n") at kernel/printk.c:614
+sys_new_debug (message_user=0x8048646 "new_debug()", tp_user=0x0)
+    at arch/x86/kernel/new_debug.c:37
+37              if (tp_user != NULL) {
+Value returned is $3 = 33
+(gdb) s
+49      }
+(gdb) finish
+Run till exit from #0  sys_new_debug (message_user=0x8048646 "new_debug()",
+    tp_user=0x0) at arch/x86/kernel/new_debug.c:49
+0xc100288c in ?? ()
+Value returned is $4 = 0
+(gdb) c
+Continuing.
+}}}
+  * s0711489@ubuntu-lucid:~$ ./a.out
+{{{
+new_debug()
+}}}
+
+ * gdb
+{{{
+Breakpoint 1, sys_new_debug (message_user=0xbfb1b9b9 "1", tp_user=0xbfb1b324)
+    at arch/x86/kernel/new_debug.c:9
+9       SYSCALL_DEFINE2(new_debug, const char *, message_user, struct timespec*, tp_user) {
+(gdb) l
+4       #include <linux/time.h>
+5
+6       /* from kernel/printk.c */
+7       #define __LOG_BUF_LEN 1024
+8
+9       SYSCALL_DEFINE2(new_debug, const char *, message_user, struct timespec*, tp_user) {
+10              int errno;
+11              static char message[__LOG_BUF_LEN];
+12              struct timespec ts;
+13              long len = 0;
+(gdb) p message
+$5 = "new_debug()", '\000' <repeats 1012 times>
+(gdb) p message_user
+$6 = 0xbfb1b9b9 "1"
+(gdb) p tp_user
+$7 = (struct timespec *) 0xbfb1b324
+(gdb) p ts
+$8 = {tv_sec = -570499584, tv_nsec = -1216356364}
+(gdb) n
+15              if(tp_user != NULL && ! access_ok(VERIFY_WRITE, tp_user, sizeof(*tp_user)) ) {
+(gdb)
+20              if (message_user == NULL) {
+(gdb)
+24              len = strnlen_user(message_user, __LOG_BUF_LEN);
+(gdb)
+25              if (len == 0 || len > __LOG_BUF_LEN) {
+(gdb)
+29              if (strncpy_from_user(message, message_user, sizeof(message) - 1) < 0) {
+(gdb)
+35              printk(KERN_DEBUG "%s\n", message);
+(gdb)
+33              message[sizeof(message) - 1] = '\0';
+(gdb)
+35              printk(KERN_DEBUG "%s\n", message);
+(gdb)
+37              if (tp_user != NULL) {
+(gdb)
+38                      getnstimeofday(&ts);
+(gdb)
+39                      if (copy_to_user(tp_user, &ts, sizeof(ts)) != 0) {
+(gdb) p ts
+$9 = {tv_sec = 1320815780, tv_nsec = 601392214}
+(gdb) p tp_user
+$10 = (struct timespec *) 0xbfb1b324
+(gdb) n
+49      }
+(gdb) p tp_user
+$11 = (struct timespec *) 0xbfb1b324
+(gdb) finish
+Run till exit from #0  sys_new_debug (message_user=0xbfb1b9b9 "1",
+    tp_user=0xbfb1b324) at arch/x86/kernel/new_debug.c:49
+0xc100288c in ?? ()
+Value returned is $12 = 0
+(gdb) c
+Continuing.
+}}}
+  * s0711489@ubuntu-lucid:~$ ./a.out 1
+{{{
+[1320815780.601392214] 1
+}}}
+
+ * s0711489@ubuntu-lucid:~$ ./a.out 1 2 3 4
+{{{
+[1320815837.554212464] 1
+[1320815837.554367435] 2
+[1320815837.554373628] 3
+[1320815837.554378429] 4
+}}}
+ * s0711489@ubuntu-lucid:~$ ./a.out 1 2 3 4
+{{{
+[1320815846.036561542] 1
+[1320815846.036726240] 2
+[1320815846.036732514] 3
+[1320815846.036737329] 4
+}}}
+ * s0711489@ubuntu-lucid:~$ tail /var/log/debug
+{{{
+Nov  9 14:14:21 ubuntu-lucid kernel: [  187.486803] new_debug()
+Nov  9 14:16:38 ubuntu-lucid kernel: [  364.616724] 1
+Nov  9 14:17:17 ubuntu-lucid kernel: [  425.607587] 1
+Nov  9 14:17:17 ubuntu-lucid kernel: [  425.607744] 2
+Nov  9 14:17:17 ubuntu-lucid kernel: [  425.607750] 3
+Nov  9 14:17:17 ubuntu-lucid kernel: [  425.607755] 4
+Nov  9 14:17:26 ubuntu-lucid kernel: [  434.089936] 1
+Nov  9 14:17:26 ubuntu-lucid kernel: [  434.090102] 2
+Nov  9 14:17:26 ubuntu-lucid kernel: [  434.090109] 3
+Nov  9 14:17:26 ubuntu-lucid kernel: [  434.090114] 4
+}}}
+
+ == fix macro for new_debug ==
+ * vim arch/x86/include/asm/new_debug.h
+{{{#!diff
+Index: arch/x86/include/asm/new_debug.h
+===================================================================
+--- arch/x86/include/asm/new_debug.h    (リビジョン 1381)
++++ arch/x86/include/asm/new_debug.h    (作業コピー)
+@@ -2,6 +2,6 @@
+ #define _ASM_X86_NEW_DEBUG_H
+ 
+ #include <asm/unistd.h>
+-#define new_debug(x) syscall(__NR_new_debug, x)
++#define new_debug(x,y) syscall(__NR_new_debug, x, y)
+ 
+ #endif /* _ASM_X86_NEW_DEBUG_H */
+}}}
+
+ * windell46:i386 s0711489$ ./build
+{{{
+Kernel: arch/x86/boot/bzImage is ready  (#12)
+}}}
+
+ == add new_debug to x86_64 ==
+ * vim arch/x86/include/asm/unistd_64.h
+{{{#!diff
+Index: arch/x86/include/asm/unistd_64.h
+===================================================================
+--- arch/x86/include/asm/unistd_64.h    (リビジョン 1397)
++++ arch/x86/include/asm/unistd_64.h    (作業コピー)
+@@ -665,6 +665,8 @@
+ __SYSCALL(__NR_recvmmsg, sys_recvmmsg)
+ #define __NR_new_hello                         300
+ __SYSCALL(__NR_new_hello, sys_new_hello)
++#define __NR_new_debug                         301
++__SYSCALL(__NR_new_debug, sys_new_debug)
+ 
+ #ifndef __NO_STUBS
+ #define __ARCH_WANT_OLD_READDIR
+}}}
+ * viola06:x86_64 s0711489$ ./build
+{{{
+Kernel: arch/x86/boot/bzImage is ready  (#5)
+}}}
+ * s0711489@ubuntu-lucid64:~$ sudo /mnt/hgfs/tools/install.sh
+
+ * s0711489@ubuntu-lucid64:~$ gcc -I /lib/modules/2.6.35.14/build/arch/x86/include/ 03/new_debug-sys.c
+
+ * s0711489@ubuntu-lucid64:~$ ./a.out
+{{{
+new_debug()
+}}}
+ * s0711489@ubuntu-lucid64:~$ ./a.out 1 2 3 4 5 6 7 8
+{{{
+[1320819346.718424802] 1
+[1320819346.718761534] 2
+[1320819346.718767685] 3
+[1320819346.718772404] 4
+[1320819346.718776934] 5
+[1320819346.718781608] 6
+[1320819346.718786123] 7
+[1320819346.718790631] 8
+}}}
+ * s0711489@ubuntu-lucid64:~$ tail /var/log/kern.log
+{{{
+Nov  9 15:15:24 ubuntu-lucid64 kernel: [   27.316107] cc1 used greatest stack depth: 4368 bytes left
+Nov  9 15:15:36 ubuntu-lucid64 kernel: [   39.137213] new_debug()
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629638] 1
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629978] 2
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629985] 3
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629990] 4
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629994] 5
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.629999] 6
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.630004] 7
+Nov  9 15:15:46 ubuntu-lucid64 kernel: [   49.630008] 8
+}}}