first commit

01_day/backtrace/backtrace.h

@@ -0,0 +1,4 @@
+#include <execinfo.h>
+#include <stdio.h>
+#include <stdlib.h>
+void print_gnu_backtrace(void);

01_day/backtrace/backtrace_1.c

@@ -0,0 +1,21 @@
+#include <execinfo.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void print_gnu_backtrace(void)
+{
+	void *  frame_addrs[16];
+	char**  frame_strings;
+	size_t backtrace_size;
+	int i;
+
+	backtrace_size = backtrace( frame_addrs, 16 );
+	frame_strings = backtrace_symbols( frame_addrs, backtrace_size );
+
+	for( i=0; i<backtrace_size; ++i )
+	{
+		printf("%d: [0x%p] %s\n", i, frame_addrs[i], frame_strings[i] );
+	}
+	free( frame_strings );
+}
+

01_day/backtrace/backtrace_2.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+typedef struct layout
+{
+	struct layout* ebp;
+	void* ret;
+} layout;
+
+void print_gnu_backtrace()
+{
+	layout* ebp = __builtin_frame_address(0);
+	while( ebp )
+	{
+		printf("0x%08x\n", (unsigned int)ebp->ret );
+		ebp = ebp->ebp;
+	}
+}

01_day/backtrace/backtrace_3.c

@@ -0,0 +1,23 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <dlfcn.h>
+
+void **getEBP(int dummy)
+{
+	void **ebp = (void**)&dummy - 2 ;
+	return (ebp);
+}
+void **save_ebp;
+void print_gnu_backtrace(void)
+{
+	int dummy;
+	void **ebp = getEBP(dummy);
+	void **ret = *(ebp + 1);
+	ebp = *ebp;
+	while(ebp)
+	{
+		printf("%p\n", ret );
+		ret = *(ebp + 1);
+		ebp = *ebp;
+	}
+}

01_day/backtrace/backtrace_4.c

@@ -0,0 +1,29 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <dlfcn.h>
+
+void **getEBP(int dummy)
+{
+	void **ebp = (void**)&dummy - 2 ;
+	return ebp;
+}
+
+void print_gnu_backtrace(void)
+{
+	int dummy;
+	int frame = 0;
+	Dl_info dlip;
+	void **ebp = getEBP(dummy);
+	void **ret = *(ebp+1);
+	ebp = *ebp;
+	printf("Stack backtrace_3:\n");
+
+	while(ebp)
+	{
+		if( dladdr(ret, &dlip) == 0 )
+			break;
+		printf("Frame %d : [ebp=%p] [ret=%p] %s\n", frame++, ebp, ret, dlip.dli_sname );
+		ret = *(ebp + 1);
+		ebp = *ebp;
+	}
+}

01_day/backtrace/backtrace_5.c

@@ -0,0 +1,24 @@
+#define UNW_LOCAL_ONLY
+#define _GNU_SOURCE
+#include <libunwind.h>
+#include <dlfcn.h>
+#include "backtrace.h"
+
+void print_gnu_backtrace (void) {
+	unw_word_t ip, sp;
+	unw_cursor_t cursor; unw_context_t uc;
+	Dl_info dlip;
+	int frame=0;
+
+	unw_getcontext(&uc);
+	unw_init_local(&cursor, &uc);
+	while (unw_step(&cursor) > 0) {
+		unw_get_reg(&cursor, UNW_REG_IP, &ip);
+		unw_get_reg(&cursor, UNW_REG_SP, &sp);
+		if( dladdr((void*)ip, &dlip) == 0 )
+			break;
+		printf("Frame %d : [ebp=%p] [ret=%p] %s\n", frame++, 
+				(void*)sp, (void*)ip, dlip.dli_sname );
+	}
+}
+

01_day/backtrace/backtrace_6.c

@@ -0,0 +1,24 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#include "backtrace.h" 
+
+void print_gnu_backtrace()
+{
+	unw_cursor_t    cursor;
+	unw_context_t   context;
+
+	unw_getcontext(&context);
+	unw_init_local(&cursor, &context);
+
+	while (unw_step(&cursor) > 0) {
+		unw_word_t  offset, pc;
+		char        fname[64];
+
+		unw_get_reg(&cursor, UNW_REG_IP, &pc);
+
+		fname[0] = '\0';
+		(void) unw_get_proc_name(&cursor, fname, sizeof(fname), &offset);
+
+		printf ("%p : (%s+0x%x) [%p]\n", (void*)pc, fname, offset, (void*)pc);
+	}
+}

01_day/backtrace/backtrace_main.c

@@ -0,0 +1,27 @@
+#include "backtrace.h"
+int foo(void)
+{
+	print_gnu_backtrace();
+	return 0;
+}
+
+int bar(void)
+{
+	foo();
+	return 0;
+}
+int boo(void)
+{
+	bar();
+	return 0;
+}
+int baz(void)
+{
+	boo();
+	return 0;
+}
+int main()
+{
+	baz();
+	return 0;
+}

01_day/corefile/readcore.c

@@ -0,0 +1,82 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <elf.h>
+#include <sys/procfs.h>
+#include <asm/ldt.h>
+
+static void * read_note(void *addr, void **pdata)
+{
+#define ALIGN(pos, size)  ((((pos) + (size-1)) / size) * size)
+
+	Elf32_Nhdr *note_hdr = addr;
+
+	/* print note name and type */
+	printf("note:  %-8s (0x%03x)\n", (char *)(note_hdr+1), note_hdr->n_type);
+
+	/* calculate data position */
+	*pdata = (void *) ((unsigned long) (note_hdr+1) + ALIGN(note_hdr->n_namesz, 4));
+
+	/* return pointer of next note header */
+	return (void *) ((unsigned long) *pdata + ALIGN(note_hdr->n_descsz, 4));
+}
+int main(void)
+{
+	prstatus_t *status;
+	prpsinfo_t *psinfo;
+	struct elf_siginfo *siginfo;
+	Elf32_auxv_t *auxv;
+	struct user_desc *ldt;
+	void *files;
+
+	FILE *fp;
+	Elf32_Ehdr elf_hdr;
+	Elf32_Phdr pgrm_hdr;
+	char buf[4096];
+	void *note;
+
+	fp = fopen("core", "r");
+
+	/* read ELF header */
+	fread(&elf_hdr, sizeof(elf_hdr), 1, fp);  
+
+	/* seek to first program header (for NOTE) */
+	fseek(fp, elf_hdr.e_phoff, SEEK_SET);
+
+	/* read program header */
+	fread(&pgrm_hdr, sizeof(pgrm_hdr), 1, fp);  
+
+	/* seek to note */
+	fseek(fp, pgrm_hdr.p_offset, SEEK_SET);
+	fread(buf, pgrm_hdr.p_filesz, 1, fp);  
+
+	note = buf;
+	note = read_note(note, (void **) &status);
+	note = read_note(note, (void **) &psinfo);
+	note = read_note(note, (void **) &siginfo);
+	note = read_note(note, (void **) &auxv);
+	note = read_note(note, (void **) &files);
+	note = read_note(note, (void **) &ldt);
+
+#define EAX    6
+#define EIP    12
+
+	printf("program name = %s\n", psinfo->pr_fname);
+	printf("signo = %d\n", status->pr_info.si_signo);
+	printf("EIP = 0x%08lx\nEAX = 0x%08lx\n", status->pr_reg[EIP], status->pr_reg[EAX]);
+
+	/* print auxiliary vector */
+	for ( ; auxv->a_type != AT_NULL; auxv++) {
+		if (auxv->a_type == AT_BASE)
+			printf("address of dynamic loader: %p\n", (void *) auxv->a_un.a_val);
+		if (auxv->a_type == AT_SYSINFO_EHDR)
+			printf("address of vdso: %p\n", (void *) auxv->a_un.a_val);
+	}
+
+	printf("gdt entry: %u, base: 0x%08x, limit: 0x%08lx\n",
+			ldt->entry_number, ldt->base_addr & ~0xfff,
+			ldt->limit_in_pages ? ldt->limit * PAGE_SIZE : ldt->limit);
+
+	return 0;
+}
+
+

01_day/corefile/segfault.c

@@ -0,0 +1,9 @@
+#include <sys/types.h>
+#include <unistd.h>
+
+int main(void)
+{
+	getchar();
+	*(int *) 0 = 1;
+	return 0;
+}

01_day/stack/stack.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+void bar(int a)
+{	
+	printf("bar(), &a=%p\n", &a);
+}
+void foo()
+{	
+	bar(1);
+//	printf("foo()\n");
+}
+
+int main()
+{
+	foo();
+	//printf("main()\n");
+	return 0;
+}