sbtools: generate a unique name for each section

This allows to manipulate the elf file more easily with objcopy for example. Executable sections are named .text0, .text1, ..., bss sections are named .bss0, .bss1, ...

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29817 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 25 insertions, 10 deletions

diff --git a/utils/sbtools/elf.c b/utils/sbtools/elf.c
index 0acaf8d..de8d9f9 100644
--- a/utils/sbtools/elf.c
+++ b/utils/sbtools/elf.c
@@ -194,11 +194,6 @@ void elf_write_file(struct elf_params_t *params, elf_write_fn_t write, void *use
     Elf32_Shdr shdr;
     memset(&ehdr, 0, EI_NIDENT);
 
-    uint32_t bss_strtbl = 1;
-    uint32_t text_strtbl = bss_strtbl + strlen(".bss") + 1;
-    uint32_t shstrtab_strtbl = text_strtbl + strlen(".text") + 1;
-    uint32_t strtbl_size = shstrtab_strtbl + strlen(".shstrtab") + 1;
-
     while(sec)
     {
         if(sec->type == EST_LOAD)
@@ -240,6 +235,17 @@ void elf_write_file(struct elf_params_t *params, elf_write_fn_t write, void *use
 
     write(user, 0, &ehdr, sizeof ehdr);
 
+    /* allocate enough size to hold any combinaison of .text/.bss in the string table:
+     * - one empty name ("\0")
+     * - at most N names of the form ".textXX\0" or ".bssXX\0"
+     * - one name ".shstrtab\0" */
+    char *strtbl_content = malloc(1 + strlen(".shstrtab") + 1 +
+        phnum * (strlen(".textXX") + 1));
+    
+    strtbl_content[0] = '\0';
+    strcpy(&strtbl_content[1], ".shstrtab");
+    uint32_t strtbl_index = 1 + strlen(".shstrtab") + 1;
+
     uint32_t data_offset = ehdr.e_ehsize + ehdr.e_phnum * ehdr.e_phentsize +
         ehdr.e_shnum * ehdr.e_shentsize;
 
@@ -289,14 +295,22 @@ void elf_write_file(struct elf_params_t *params, elf_write_fn_t write, void *use
 
         offset += sizeof(Elf32_Shdr);
     }
-    
+
+    uint32_t text_idx = 0;
+    uint32_t bss_idx = 0;
     while(sec)
     {
-        shdr.sh_name = text_strtbl;
+        shdr.sh_name = strtbl_index;
         if(sec->type == EST_LOAD)
+        {
+            strtbl_index += 1 + sprintf(&strtbl_content[strtbl_index], ".text%d", text_idx++);
             shdr.sh_type = SHT_PROGBITS;
+        }
         else
+        {
+            strtbl_index += 1 + sprintf(&strtbl_content[strtbl_index], ".bss%d", bss_idx++);
             shdr.sh_type = SHT_NOBITS;
+        }
         shdr.sh_flags = SHF_ALLOC | SHF_EXECINSTR;
         shdr.sh_addr = sec->addr;
         shdr.sh_offset = sec->offset;
@@ -313,12 +327,12 @@ void elf_write_file(struct elf_params_t *params, elf_write_fn_t write, void *use
     }
 
     {
-        shdr.sh_name = shstrtab_strtbl;
+        shdr.sh_name = 1;
         shdr.sh_type = SHT_STRTAB;
         shdr.sh_flags = 0;
         shdr.sh_addr = 0;
         shdr.sh_offset = strtbl_offset + data_offset;
-        shdr.sh_size = strtbl_size;
+        shdr.sh_size = strtbl_index;
         shdr.sh_link = SHN_UNDEF;
         shdr.sh_info = 0;
         shdr.sh_addralign = 1;
@@ -337,7 +351,8 @@ void elf_write_file(struct elf_params_t *params, elf_write_fn_t write, void *use
         sec = sec->next;
     }
 
-    write(user, strtbl_offset + data_offset, "\0.bss\0.text\0.shstrtab\0", strtbl_size);
+    write(user, strtbl_offset + data_offset, strtbl_content, strtbl_index);
+    free(strtbl_content);
 }
 
 bool elf_read_file(struct elf_params_t *params, elf_read_fn_t read,