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module loading for 2.4: use fd-based io instead of FILE based;

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use xlseek and xread; simpler check for ELF signature.

   text    data     bss     dec     hex filename
 824460     476    7616  832552   cb428 busybox_old
 824333     476    7616  832425   cb3a9 busybox_unstripped
This commit is contained in:
Denis Vlasenko 2009-03-29 16:38:59 +00:00
parent fd303b11ef
commit e1de3af989
1 changed files with 27 additions and 35 deletions
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62
modutils/modutils-24.c
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@ -625,7 +625,7 @@ static unsigned long obj_load_size(struct obj_file *f);
static int obj_relocate(struct obj_file *f, ElfW(Addr) base); static int obj_relocate(struct obj_file *f, ElfW(Addr) base);
static struct obj_file *obj_load(FILE *f, int loadprogbits); static struct obj_file *obj_load(int fd, int loadprogbits);
static int obj_create_image(struct obj_file *f, char *image); static int obj_create_image(struct obj_file *f, char *image);
@ -3191,8 +3191,13 @@ static int obj_create_image(struct obj_file *f, char *image)
/*======================================================================*/ /*======================================================================*/
static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM) static struct obj_file *obj_load(int fd, int loadprogbits UNUSED_PARAM)
{ {
#if BB_LITTLE_ENDIAN
# define ELFMAG_U32 ((uint32_t)(ELFMAG0 + 0x100 * (ELFMAG1 + (0x100 * (ELFMAG2 + 0x100 * ELFMAG3)))))
#else
# define ELFMAG_U32 ((uint32_t)((((ELFMAG0 * 0x100) + ELFMAG1) * 0x100 + ELFMAG2) * 0x100 + ELFMAG3))
#endif
struct obj_file *f; struct obj_file *f;
ElfW(Shdr) * section_headers; ElfW(Shdr) * section_headers;
size_t shnum, i; size_t shnum, i;
@ -3205,16 +3210,10 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM)
f->symbol_hash = obj_elf_hash; f->symbol_hash = obj_elf_hash;
f->load_order_search_start = &f->load_order; f->load_order_search_start = &f->load_order;
fseek(fp, 0, SEEK_SET); xlseek(fd, 0, SEEK_SET);
if (fread(&f->header, sizeof(f->header), 1, fp) != 1) { xread(fd, &f->header, sizeof(f->header));
bb_perror_msg_and_die("error reading ELF header");
}
if (f->header.e_ident[EI_MAG0] != ELFMAG0 if (*(uint32_t*)(&f->header.e_ident) != ELFMAG_U32) {
|| f->header.e_ident[EI_MAG1] != ELFMAG1
|| f->header.e_ident[EI_MAG2] != ELFMAG2
|| f->header.e_ident[EI_MAG3] != ELFMAG3
) {
bb_error_msg_and_die("not an ELF file"); bb_error_msg_and_die("not an ELF file");
} }
if (f->header.e_ident[EI_CLASS] != ELFCLASSM if (f->header.e_ident[EI_CLASS] != ELFCLASSM
@ -3243,10 +3242,8 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM)
f->sections = xzalloc(sizeof(f->sections[0]) * (shnum + 4)); f->sections = xzalloc(sizeof(f->sections[0]) * (shnum + 4));
section_headers = alloca(sizeof(ElfW(Shdr)) * shnum); section_headers = alloca(sizeof(ElfW(Shdr)) * shnum);
fseek(fp, f->header.e_shoff, SEEK_SET); xlseek(fd, f->header.e_shoff, SEEK_SET);
if (fread(section_headers, sizeof(ElfW(Shdr)), shnum, fp) != shnum) { xread(fd, section_headers, sizeof(ElfW(Shdr)) * shnum);
bb_perror_msg_and_die("error reading ELF section headers");
}
/* Read the section data. */ /* Read the section data. */
@ -3278,10 +3275,8 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM)
sec->contents = NULL; sec->contents = NULL;
if (sec->header.sh_size > 0) { if (sec->header.sh_size > 0) {
sec->contents = xmalloc(sec->header.sh_size); sec->contents = xmalloc(sec->header.sh_size);
fseek(fp, sec->header.sh_offset, SEEK_SET); xlseek(fd, sec->header.sh_offset, SEEK_SET);
if (fread(sec->contents, sec->header.sh_size, 1, fp) != 1) { xread(fd, sec->contents, sec->header.sh_size);
bb_perror_msg_and_die("error reading ELF section data");
}
} }
break; break;
#if SHT_RELM == SHT_REL #if SHT_RELM == SHT_REL
@ -3397,27 +3392,24 @@ static struct obj_file *obj_load(FILE *fp, int loadprogbits UNUSED_PARAM)
* kernel for the module * kernel for the module
*/ */
static int obj_load_progbits(FILE *fp, struct obj_file *f, char *imagebase) static int obj_load_progbits(int fd, struct obj_file *f, char *imagebase)
{ {
ElfW(Addr) base = f->baseaddr; ElfW(Addr) base = f->baseaddr;
struct obj_section* sec; struct obj_section* sec;
for (sec = f->load_order; sec; sec = sec->load_next) { for (sec = f->load_order; sec; sec = sec->load_next) {
/* section already loaded? */ /* section already loaded? */
if (sec->contents != NULL) if (sec->contents != NULL)
continue; continue;
if (sec->header.sh_size == 0) if (sec->header.sh_size == 0)
continue; continue;
sec->contents = imagebase + (sec->header.sh_addr - base); sec->contents = imagebase + (sec->header.sh_addr - base);
fseek(fp, sec->header.sh_offset, SEEK_SET); xlseek(fd, sec->header.sh_offset, SEEK_SET);
if (fread(sec->contents, sec->header.sh_size, 1, fp) != 1) { errno = 0; /* read may be short without errno being set */
if (full_read(fd, sec->contents, sec->header.sh_size) != sec->header.sh_size) {
bb_perror_msg("error reading ELF section data"); bb_perror_msg("error reading ELF section data");
return 0; return 0;
} }
} }
return 1; return 1;
} }
@ -3779,22 +3771,23 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options)
struct utsname uts; struct utsname uts;
int exit_status = EXIT_FAILURE; int exit_status = EXIT_FAILURE;
int m_has_modinfo; int m_has_modinfo;
char *m_name; char *m_name, *p;
#if ENABLE_FEATURE_INSMOD_VERSION_CHECKING #if ENABLE_FEATURE_INSMOD_VERSION_CHECKING
char m_strversion[STRVERSIONLEN]; char m_strversion[STRVERSIONLEN];
int m_version, m_crcs; int m_version, m_crcs;
#endif #endif
FILE *fp; int fd;
uname(&uts); uname(&uts);
fp = fopen_for_read(m_filename); fd = open_or_warn(m_filename, O_RDONLY);
if (fp == NULL) if (fd < 0)
return EXIT_FAILURE; return EXIT_FAILURE;
m_name = xstrdup(bb_basename(m_filename)); m_name = xstrdup(bb_basename(m_filename));
*strrchr(m_name, '.') = 0; p = strrchr(m_name, '.');
if (p) *p = '\0';
f = obj_load(fp, LOADBITS); f = obj_load(fd, LOADBITS);
m_has_modinfo = (get_modinfo_value(f, "kernel_version") != NULL); m_has_modinfo = (get_modinfo_value(f, "kernel_version") != NULL);
@ -3876,7 +3869,7 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options)
* the PROGBITS section was not loaded by the obj_load * the PROGBITS section was not loaded by the obj_load
* now we can load them directly into the kernel memory * now we can load them directly into the kernel memory
*/ */
if (!obj_load_progbits(fp, f, (char*)m_addr)) { if (!obj_load_progbits(fd, f, (char*)m_addr)) {
delete_module(m_name, 0); delete_module(m_name, 0);
goto out; goto out;
} }
@ -3898,8 +3891,7 @@ int FAST_FUNC bb_init_module_24(const char *m_filename, const char *options)
exit_status = EXIT_SUCCESS; exit_status = EXIT_SUCCESS;
out: out:
if (fp) close(fd);
fclose(fp);
free(m_name); free(m_name);
return exit_status; return exit_status;