full rewrite

1 files changed, 127 insertions, 183 deletions

diff --git a/dwarf.c b/dwarf.c
index 7d305fe..637d710 100644
--- a/dwarf.c
+++ b/dwarf.c
@@ -1,198 +1,142 @@
-/*
-  Copyright (c) 2009, David Anderson.
-  All rights reserved.
- 
-  Redistribution and use in source and binary forms, with or without
-  modification, are permitted provided that the following conditions are met:
-  * Redistributions of source code must retain the above copyright
-    notice, this list of conditions and the following disclaimer.
-  * Redistributions in binary form must reproduce the above copyright
-    notice, this list of conditions and the following disclaimer in the
-    documentation and/or other materials provided with the distribution.
-  * Neither the name of the example nor the
-    names of its contributors may be used to endorse or promote products
-    derived from this software without specific prior written permission.
- 
-  THIS SOFTWARE IS PROVIDED BY David Anderson ''AS IS'' AND ANY
-  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-  DISCLAIMED. IN NO EVENT SHALL David Anderson BE LIABLE FOR ANY
-  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- 
-*/
-/* simplereader.c
-   This is an example of code reading dwarf .debug_info.
-   It is kept as simple as possible to expose essential features.
-   It does not do all possible error reporting or error handling.
-
-   To use, try
-       make
-       ./simplereader simplereader
-*/
-#include <sys/types.h> /* For open() */
-#include <sys/stat.h>  /* For open() */
-#include <fcntl.h>     /* For open() */
-#include <stdlib.h>     /* For exit() */
-#include <unistd.h>     /* For close() */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
 #include <stdio.h>
 #include <errno.h>
 #include "dwarf.h"
 #include "libdwarf.h"
 
 
-static void read_cu_list(Dwarf_Debug dbg);
-static void print_die_data(Dwarf_Debug dbg, Dwarf_Die print_me,int level);
-static void get_die_and_siblings(Dwarf_Debug dbg, Dwarf_Die in_die,int in_level);
-
-int 
-main(int argc, char **argv)
-{
-
-    Dwarf_Debug dbg = 0;
-    int fd = -1;
-    const char *filepath = "<stdin>";
-    int res = DW_DLV_ERROR;
-    Dwarf_Error error;
-    Dwarf_Handler errhand = 0;
-    Dwarf_Ptr errarg = 0;
-
-    if(argc < 2) {
-        fd = 0; /* stdin */
-    } else {
-        filepath = argv[1];
-        fd = open(filepath,O_RDONLY);
-    }
-    if(fd < 0) {
-        printf("Failure attempting to open %s\n",filepath);
-    }
-    res = dwarf_init(fd,DW_DLC_READ,errhand,errarg, &dbg,&error);
-    if(res != DW_DLV_OK) {
-        printf("Giving up, cannot do DWARF processing\n");
-        exit(1);
-    }
-
-    read_cu_list(dbg);
-    res = dwarf_finish(dbg,&error);
-    if(res != DW_DLV_OK) {
-        printf("dwarf_finish failed!\n");
-    }
-    close(fd);
-    return 0;
-}
+static void parse_dwarf(Dwarf_Debug dbg, const char *struct_name, const char *field_name);
+static void parse_level(Dwarf_Debug dbg, Dwarf_Die die, const char *struct_name, const char *field_name, int level);
 
-static void 
-read_cu_list(Dwarf_Debug dbg)
-{
-    Dwarf_Unsigned cu_header_length = 0;
-    Dwarf_Half version_stamp = 0;
-    Dwarf_Unsigned abbrev_offset = 0;
-    Dwarf_Half address_size = 0;
-    Dwarf_Unsigned next_cu_header = 0;
-    Dwarf_Error error;
-    int cu_number = 0;
-
-    for(;;++cu_number) {
-        Dwarf_Die no_die = 0;
-        Dwarf_Die cu_die = 0;
-        int res = DW_DLV_ERROR;
-        res = dwarf_next_cu_header(dbg,&cu_header_length,
-            &version_stamp, &abbrev_offset, &address_size,
-            &next_cu_header, &error);
-        if(res == DW_DLV_ERROR) {
-            printf("Error in dwarf_next_cu_header\n");
-            exit(1);
-        }
-        if(res == DW_DLV_NO_ENTRY) {
-            /* Done. */
-            return;
-        }
-        /* The CU will have a single sibling, a cu_die. */
-        res = dwarf_siblingof(dbg,no_die,&cu_die,&error);
-        if(res == DW_DLV_ERROR) {
-            printf("Error in dwarf_siblingof on CU die \n");
-            exit(1);
-        }
-        if(res == DW_DLV_NO_ENTRY) {
-            /* Impossible case. */
-            printf("no entry! in dwarf_siblingof on CU die \n");
-            exit(1);
-        }
-        get_die_and_siblings(dbg,cu_die,0);
-        dwarf_dealloc(dbg,cu_die,DW_DLA_DIE);
-    }
+void usage(char *argv[]) {
+	printf("%s file struct field\n", argv[0]);
 }
 
-static void
-get_die_and_siblings(Dwarf_Debug dbg, Dwarf_Die in_die,int in_level)
-{
-    int res = DW_DLV_ERROR;
-    Dwarf_Die cur_die=in_die;
-    Dwarf_Die child = 0;
-    Dwarf_Error error;
-    print_die_data(dbg,in_die,in_level);
-
-    for(;;) {
-        Dwarf_Die sib_die = 0;
-        res = dwarf_child(cur_die,&child,&error);
-        if(res == DW_DLV_ERROR) {
-            printf("Error in dwarf_child , level %d \n",in_level);
-            exit(1);
-        }
-        if(res == DW_DLV_OK) {
-            get_die_and_siblings(dbg,child,in_level+1);
-        }
-        /* res == DW_DLV_NO_ENTRY */
-        res = dwarf_siblingof(dbg,cur_die,&sib_die,&error);
-        if(res == DW_DLV_ERROR) {
-            printf("Error in dwarf_siblingof , level %d \n",in_level);
-            exit(1);
-        }
-        if(res == DW_DLV_NO_ENTRY) {
-            /* Done at this level. */
-            break;
-        }
-        /* res == DW_DLV_OK */
-        if(cur_die != in_die) {
-            dwarf_dealloc(dbg,cur_die,DW_DLA_DIE);
-        }
-        cur_die = sib_die;
-    }
-    return;
+int main(int argc, char *argv[]) {
+	Dwarf_Debug dbg = 0;
+	int fd = -1;
+	const char *filepath;
+	const char *struct_name, *field_name;
+	int res = DW_DLV_ERROR;
+	Dwarf_Error error;
+	Dwarf_Handler errhand = 0;
+	Dwarf_Ptr errarg = 0;
+
+	if(argc < 4) {
+		usage(argv);
+		exit(1);
+	}
+
+	filepath = argv[1];
+	struct_name = argv[2];
+	field_name = argv[3];
+
+	fd = open(filepath,O_RDONLY);
+	if(fd < 0) {
+		printf("Failure attempting to open %s\n",filepath);
+	}
+	res = dwarf_init(fd,DW_DLC_READ,errhand,errarg, &dbg,&error);
+	if(res != DW_DLV_OK) {
+		printf("Giving up, cannot do DWARF processing\n");
+		exit(1);
+	}
+
+	parse_dwarf(dbg, struct_name, field_name);
+
+	res = dwarf_finish(dbg,&error);
+	if(res != DW_DLV_OK) {
+		printf("dwarf_finish failed!\n");
+	}
+	close(fd);
+	return 0;
 }
 
-static void
-print_die_data(Dwarf_Debug dbg, Dwarf_Die print_me,int level)
-{
-    char *name = 0;
-    Dwarf_Error error = 0;
-    Dwarf_Half tag = 0;
-    const char *tagname = 0;
-    int res = dwarf_diename(print_me,&name,&error);
-    if(res == DW_DLV_ERROR) {
-        printf("Error in dwarf_diename , level %d \n",level);
-        exit(1);
-    }
-    if(res == DW_DLV_NO_ENTRY) {
-        return;
-    }
-    res = dwarf_tag(print_me,&tag,&error);
-    if(res != DW_DLV_OK) {
-        printf("Error in dwarf_tag , level %d \n",level);
-        exit(1);
-    }
-    res = dwarf_get_TAG_name(tag,&tagname);
-    if(res != DW_DLV_OK) {
-        printf("Error in dwarf_get_TAG_name , level %d \n",level);
-        exit(1);
-    }
-    printf("<%d> tag: %d %s  name: %s\n",level,tag,tagname,name);
-    dwarf_dealloc(dbg,name,DW_DLA_STRING);
+static void parse_dwarf(Dwarf_Debug dbg, const char *struct_name,
+		const char *field_name) {
+	Dwarf_Bool is_info = 1;
+	Dwarf_Unsigned cu_length;
+	Dwarf_Half cu_version;
+	Dwarf_Off cu_abbrev_offset;
+	Dwarf_Half cu_pointer_size;
+	Dwarf_Half cu_offset_size;
+	Dwarf_Half cu_extension_size;
+	Dwarf_Sig8 type_signature;
+	Dwarf_Unsigned type_offset;
+	Dwarf_Unsigned cu_next_offset;
+	Dwarf_Error err;
+	int rc;
+
+
+	while (1) {
+		Dwarf_Die die, next;
+
+		rc = dwarf_next_cu_header_c(dbg, is_info, &cu_length,
+			&cu_version, &cu_abbrev_offset, &cu_pointer_size,
+			&cu_offset_size, &cu_extension_size, &type_signature,
+			&type_offset, &cu_next_offset, &err);
+
+		if (rc == DW_DLV_NO_ENTRY)
+			break;
+		if (rc != DW_DLV_OK) {
+			printf("error dwarf_next_cu_header_c: %d %s\n", rc, dwarf_errmsg(err));
+			exit(1);
+		}
+
+
+		rc = dwarf_siblingof(dbg, NULL, &die, &err);
+		if (rc != DW_DLV_OK) {
+			printf("first dwarf_siblingof failed: %d %s\n", rc, dwarf_errmsg(err));
+			exit(1);
+		}
+
+		parse_level(dbg, die, struct_name, field_name, 0);
+	}
+
+	printf("struct %s / member %s not found\n", struct_name, field_name);
+	exit(2);
 }
 
+static void parse_level(Dwarf_Debug dbg, Dwarf_Die die, const char *struct_name, const char *field_name, int level) {
+	Dwarf_Die next;
+	Dwarf_Error err;
+	int rc;
+
+	do {
+		char *name;
+		const char *tag_name;
+		Dwarf_Half tag;
 
+		rc = dwarf_diename(die, &name, &err);
+		if (rc == DW_DLV_NO_ENTRY) {
+			printf("no diename for %p?\n", die);
+			break;
+		}
+		if (rc != DW_DLV_OK) {
+			printf("dwarf_diename error: %d %s\n", rc, dwarf_errmsg(err));
+			exit(1);
+		}
 
+		rc = dwarf_tag(die, &tag, &err);
+		if (rc != DW_DLV_OK) {
+			printf("dwarf_tag error: %d %s\n", rc, dwarf_errmsg(err));
+			exit(1);
+		}
+
+		rc = dwarf_get_TAG_name(tag, &tag_name);
+		if (rc != DW_DLV_OK) {
+			printf("dwarf_get_TAG_name error: %d\n", rc);
+			exit(1);
+		}
+
+		printf("<%d> %p <%d> %s: %s\n", level, die, tag, tag_name, name);
+
+		rc = dwarf_siblingof(dbg, die, &next, &err);
+		dwarf_dealloc(dbg, die, DW_DLA_DIE);
+
+		die = next;
+	} while (die);
+}