gdb.base/sym-file.exp, hide guts of the custom loader.

This test uses a simple custom elf loader, implemented in
gdb.base/sym-file-loader.h|c.  This loader doesn't have a dlclose-like
function today, but I'll need one.  But, I found that the guts of the
loader are exposed too much to the client, making the interface more
complicated than necessary.  It's simpler if the loader just exports a
few dlopen/dlsym -style functions.  That's what this patch does.

Tested on x86_86 Fedora 17, native and gdbserver.

gdb/testsuite/
2014-04-15  Pedro Alves  <palves@redhat.com>

	* gdb.base/sym-file-loader.h: Move inclusion of <inttypes.h>,
	<ansidecl.h>, <elf/common.h> and <elf/external.h> to
	sym-file-loader.c.
	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
	to sym-file-loader.c.
	(struct library): Forward declare.
	(load_shlib, lookup_function): Change prototypes.
	(find_shstrtab, find_strtab, find_shdr, find_symtab)
	(translate_offset): Remove declarations.
	(get_text_addr): New declaration.
	* gdb.base/sym-file-loader.c: Move inclusion of <inttypes.h>,
	<ansidecl.h>, <elf/common.h> and <elf/external.h> here from
	sym-file-loader.h.
	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
	here from sym-file-loader.h.
	(struct library): New structure.
	(load_shlib, lookup_function): Change prototypes and adjust to
	work with a struct library.
	(find_shstrtab, find_strtab, find_shdr, find_symtab)
	(translate_offset): Make static.
	(get_text_addr): New function.
	* gdb.base/sym-file-main.c (main): Adjust to new loader interface.

gdb/testsuite/ChangeLog

@@ -1,3 +1,30 @@
+2014-04-15  Pedro Alves  <palves@redhat.com>
+
+	* gdb.base/sym-file-loader.h: Move inclusion of <inttypes.h>,
+	<ansidecl.h>, <elf/common.h> and <elf/external.h> to
+	sym-file-loader.c.
+	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
+	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
+	to sym-file-loader.c.
+	(struct library): Forward declare.
+	(load_shlib, lookup_function): Change prototypes.
+	(find_shstrtab, find_strtab, find_shdr, find_symtab)
+	(translate_offset): Remove declarations.
+	(get_text_addr): New declaration.
+	* gdb.base/sym-file-loader.c: Move inclusion of <inttypes.h>,
+	<ansidecl.h>, <elf/common.h> and <elf/external.h> here from
+	sym-file-loader.h.
+	(Elf_External_Phdr, Elf_External_Ehdr, Elf_External_Shdr)
+	(Elf_External_Sym, Elf_Addr, GET, GETADDR, struct segment): Move
+	here from sym-file-loader.h.
+	(struct library): New structure.
+	(load_shlib, lookup_function): Change prototypes and adjust to
+	work with a struct library.
+	(find_shstrtab, find_strtab, find_shdr, find_symtab)
+	(translate_offset): Make static.
+	(get_text_addr): New function.
+	* gdb.base/sym-file-main.c (main): Adjust to new loader interface.
+
 2014-04-15  Pedro Alves  <palves@redhat.com>
 
 	* gdb.base/sym-file-loader.c: Fix typo.  SELF_LINK, not SELK_LINK.

gdb/testsuite/gdb.base/sym-file-loader.c

@@ -23,6 +23,59 @@
 
 #include "sym-file-loader.h"
 
+#include <inttypes.h>
+#include <ansidecl.h>
+#include <elf/common.h>
+#include <elf/external.h>
+
+#ifdef TARGET_LP64
+
+typedef Elf64_External_Phdr Elf_External_Phdr;
+typedef Elf64_External_Ehdr Elf_External_Ehdr;
+typedef Elf64_External_Shdr Elf_External_Shdr;
+typedef Elf64_External_Sym Elf_External_Sym;
+typedef uint64_t Elf_Addr;
+
+#elif defined TARGET_ILP32
+
+typedef Elf32_External_Phdr Elf_External_Phdr;
+typedef Elf32_External_Ehdr Elf_External_Ehdr;
+typedef Elf32_External_Shdr Elf_External_Shdr;
+typedef Elf32_External_Sym Elf_External_Sym;
+typedef uint32_t Elf_Addr;
+
+#endif
+
+#define GET(hdr, field) (\
+sizeof ((hdr)->field) == 1 ? (uint64_t) (hdr)->field[0] : \
+sizeof ((hdr)->field) == 2 ? (uint64_t) *(uint16_t *) (hdr)->field : \
+sizeof ((hdr)->field) == 4 ? (uint64_t) *(uint32_t *) (hdr)->field : \
+sizeof ((hdr)->field) == 8 ? *(uint64_t *) (hdr)->field : \
+*(uint64_t *) NULL)
+
+#define GETADDR(hdr, field) (\
+sizeof ((hdr)->field) == sizeof (Elf_Addr) ? *(Elf_Addr *) (hdr)->field : \
+*(Elf_Addr *) NULL)
+
+struct segment
+{
+  uint8_t *mapped_addr;
+  Elf_External_Phdr *phdr;
+  struct segment *next;
+};
+
+struct library
+{
+  int fd;
+  Elf_External_Ehdr *ehdr;
+  struct segment *segments;
+};
+
+static Elf_External_Shdr *find_shdr (Elf_External_Ehdr *ehdr,
+				     const char *section);
+static int translate_offset (uint64_t file_offset, struct segment *seg,
+			     void **addr);
+
 #ifdef TARGET_LP64
 
 uint8_t
@@ -123,10 +176,10 @@ get_origin (void)
 /* Mini shared library loader.  No reallocation
    is performed for the sake of simplicity.  */
 
-int
+struct library *
-load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
+load_shlib (const char *file)
-	    struct segment **seg_out)
 {
+  struct library *lib;
   uint64_t i;
   int fd = -1;
   off_t fsize;
@@ -148,7 +201,7 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
       if (origin == NULL)
 	{
 	  fprintf (stderr, "get_origin not implemented.");
-	  return -1;
+	  return NULL;
 	}
 
       path = alloca (strlen (origin) + 1 + strlen (file) + 1);
@@ -162,7 +215,7 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
   if (fd < 0)
     {
       perror ("fopen failed.");
-      return -1;
+      return NULL;
     }
 
   fsize = lseek (fd, 0, SEEK_END);
@@ -170,14 +223,14 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
   if (fsize < 0)
     {
       perror ("lseek failed.");
-      return -1;
+      return NULL;
     }
 
   addr = (uint8_t *) mmap (NULL, fsize, PROT_READ, MAP_PRIVATE, fd, 0);
   if (addr == (uint8_t *) -1)
     {
       perror ("mmap failed.");
-      return -1;
+      return NULL;
     }
 
   /* Check if the lib is an ELF file.  */
@@ -188,7 +241,7 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
       || ehdr->e_ident[EI_MAG3] != ELFMAG3)
     {
       printf ("Not an ELF file: %x\n", ehdr->e_ident[EI_MAG0]);
-      return -1;
+      return NULL;
     }
 
   if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
@@ -196,7 +249,7 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
       if (sizeof (void *) != 4)
 	{
 	  printf ("Architecture mismatch.");
-	  return -1;
+	  return NULL;
 	}
     }
   else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
@@ -204,10 +257,19 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
       if (sizeof (void *) != 8)
 	{
 	  printf ("Architecture mismatch.");
-	  return -1;
+	  return NULL;
 	}
     }
 
+  lib = malloc (sizeof (struct library));
+  if (lib == NULL)
+    {
+      printf ("malloc failed.");
+      return NULL;
+    }
+
+  lib->fd = fd;
+
   /* Load the program segments.  For the sake of simplicity
      assume that no reallocation is needed.  */
   phdr = (Elf_External_Phdr *) (addr + GET (ehdr, e_phoff));
@@ -223,8 +285,25 @@ load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
 	    head_seg = next_seg;
 	}
     }
-  *ehdr_out = ehdr;
+  lib->ehdr = ehdr;
-  *seg_out = head_seg;
+  lib->segments = head_seg;
+  return lib;
+}
+
+int
+get_text_addr (struct library *lib, void **text_addr)
+{
+  Elf_External_Shdr *text;
+
+  /* Get the text section.  */
+  text = find_shdr (lib->ehdr, ".text");
+  if (text == NULL)
+    return -1;
+
+  if (translate_offset (GET (text, sh_offset), lib->segments, text_addr)
+      != 0)
+    return -1;
+
   return 0;
 }
 
@@ -289,7 +368,7 @@ find_strtab (Elf_External_Ehdr *ehdr,
 
 /* Return the section header named SECTION.  */
 
-Elf_External_Shdr *
+static Elf_External_Shdr *
 find_shdr (Elf_External_Ehdr *ehdr, const char *section)
 {
   uint64_t shstrtab_size = 0;
@@ -317,7 +396,7 @@ find_shdr (Elf_External_Ehdr *ehdr, const char *section)
 
 /* Return the symbol table.  */
 
-Elf_External_Sym *
+static Elf_External_Sym *
 find_symtab (Elf_External_Ehdr *ehdr, uint64_t *symtab_size)
 {
   uint64_t i;
@@ -337,7 +416,7 @@ find_symtab (Elf_External_Ehdr *ehdr, uint64_t *symtab_size)
 
 /* Translate a file offset to an address in a loaded segment.   */
 
-int
+static int
 translate_offset (uint64_t file_offset, struct segment *seg, void **addr)
 {
   while (seg)
@@ -369,14 +448,15 @@ translate_offset (uint64_t file_offset, struct segment *seg, void **addr)
 /* Lookup the address of FUNC.  */
 
 int
-lookup_function (const char *func,
+lookup_function (struct library *lib, const char *func, void **addr)
-		 Elf_External_Ehdr *ehdr, struct segment *seg, void **addr)
 {
   const char *strtab;
   uint64_t strtab_size = 0;
   Elf_External_Sym *symtab;
   uint64_t symtab_size = 0;
   uint64_t i;
+  Elf_External_Ehdr *ehdr = lib->ehdr;
+  struct segment *seg = lib->segments;
 
   /* Get the string table for the symbols.  */
   strtab = find_strtab (ehdr, ".strtab", &strtab_size);

gdb/testsuite/gdb.base/sym-file-loader.h

@@ -16,84 +16,21 @@
 #ifndef __SYM_FILE_LOADER__
 #define __SYM_FILE_LOADER__
 
-#include <inttypes.h>
+struct library;
-#include <ansidecl.h>
-#include <elf/common.h>
-#include <elf/external.h>
-
-#ifdef TARGET_LP64
-
-typedef Elf64_External_Phdr Elf_External_Phdr;
-typedef Elf64_External_Ehdr Elf_External_Ehdr;
-typedef Elf64_External_Shdr Elf_External_Shdr;
-typedef Elf64_External_Sym Elf_External_Sym;
-typedef uint64_t Elf_Addr;
-
-#elif defined TARGET_ILP32
-
-typedef Elf32_External_Phdr Elf_External_Phdr;
-typedef Elf32_External_Ehdr Elf_External_Ehdr;
-typedef Elf32_External_Shdr Elf_External_Shdr;
-typedef Elf32_External_Sym Elf_External_Sym;
-typedef uint32_t Elf_Addr;
-
-#endif
-
-#define GET(hdr, field) (\
-sizeof ((hdr)->field) == 1 ? (uint64_t) (hdr)->field[0] : \
-sizeof ((hdr)->field) == 2 ? (uint64_t) *(uint16_t *) (hdr)->field : \
-sizeof ((hdr)->field) == 4 ? (uint64_t) *(uint32_t *) (hdr)->field : \
-sizeof ((hdr)->field) == 8 ? *(uint64_t *) (hdr)->field : \
-*(uint64_t *) NULL)
-
-#define GETADDR(hdr, field) (\
-sizeof ((hdr)->field) == sizeof (Elf_Addr) ? *(Elf_Addr *) (hdr)->field : \
-*(Elf_Addr *) NULL)
-
-struct segment
-{
-  uint8_t *mapped_addr;
-  Elf_External_Phdr *phdr;
-  struct segment *next;
-};
 
 /* Mini shared library loader.  No reallocation is performed
    for the sake of simplicity.  */
 
-int
+/* Load a library.  */
-load_shlib (const char *file, Elf_External_Ehdr **ehdr_out,
-	    struct segment **seg_out);
 
-/* Return the section-header table.  */
+struct library *load_shlib (const char *file);
-
-Elf_External_Shdr *find_shdrtab (Elf_External_Ehdr *ehdr);
-
-/* Return the string table of the section headers.  */
-
-const char *find_shstrtab (Elf_External_Ehdr *ehdr, uint64_t *size);
-
-/* Return the string table named SECTION.  */
-
-const char *find_strtab (Elf_External_Ehdr *ehdr,
-			 const char *section, uint64_t *strtab_size);
-
-/* Return the section header named SECTION.  */
-
-Elf_External_Shdr *find_shdr (Elf_External_Ehdr *ehdr, const char *section);
-
-/* Return the symbol table.  */
-
-Elf_External_Sym *find_symtab (Elf_External_Ehdr *ehdr,
-			       uint64_t *symtab_size);
-
-/* Translate a file offset to an address in a loaded segment.   */
-
-int translate_offset (uint64_t file_offset, struct segment *seg, void **addr);
 
 /* Lookup the address of FUNC.  */
 
-int
+int lookup_function (struct library *lib, const char *func, void **addr);
-lookup_function (const char *func, Elf_External_Ehdr* ehdr,
+
-		 struct segment *seg, void **addr);
+/* Return the library's loaded text address.  */
+
+int get_text_addr (struct library *lib, void **text_addr);
 
 #endif

gdb/testsuite/gdb.base/sym-file-main.c

@@ -38,37 +38,29 @@ int
 main (int argc, const char *argv[])
 {
   const char *file = SHLIB_NAME;
-  Elf_External_Ehdr *ehdr = NULL;
+  struct library *lib;
-  struct segment *head_seg = NULL;
-  Elf_External_Shdr *text;
   char *text_addr = NULL;
   int (*pbar) () = NULL;
   int (*pfoo) (int) = NULL;
 
-  if (load_shlib (file, &ehdr, &head_seg) != 0)
+  lib = load_shlib (file);
-    return -1;
+  if (lib == NULL)
+    return 1;
 
-  /* Get the text section.  */
+  if (get_text_addr (lib,  (void **) &text_addr) != 0)
-  text = find_shdr (ehdr, ".text");
+    return 1;
-  if (text == NULL)
-    return -1;
-
-  /* Notify GDB to add the symbol file.  */
-  if (translate_offset (GET (text, sh_offset), head_seg, (void **) &text_addr)
-      != 0)
-    return -1;
 
   gdb_add_symbol_file (text_addr, file);
 
   /* Call bar from SHLIB_NAME.  */
-  if (lookup_function ("bar", ehdr, head_seg, (void *) &pbar) != 0)
+  if (lookup_function (lib, "bar", (void *) &pbar) != 0)
-    return -1;
+    return 1;
 
   (*pbar) ();
 
   /* Call foo from SHLIB_NAME.  */
-  if (lookup_function ("foo", ehdr, head_seg, (void *) &pfoo) != 0)
+  if (lookup_function (lib, "foo", (void *) &pfoo) != 0)
-    return -1;
+    return 1;
 
   (*pfoo) (2);