diff options
| -rw-r--r-- | ChangeLog | 9 | ||||
| -rw-r--r-- | elf/dl-load.c | 193 | ||||
| -rw-r--r-- | elf/ldsodefs.h | 5 |
3 files changed, 135 insertions, 72 deletions
@@ -1,3 +1,12 @@ +1999-02-19 Ulrich Drepper <drepper@cygnus.com> + + * elf/ldsodefs.h (_dl_signal_error): Mark as __noreturn__. + * elf/dl-load.c (lose): Make it a function at the toplevel, mark as + noreturn, and prevent it from being inlined. + Define LOSE appropriately. + (_dl_map_object_from_fd): Compare all bytes in e_ident at once. + Optimize decoding of p_flags for certain platforms. + 1999-02-19 Philip Blundell <pb@nexus.co.uk> * Makeconfig (link-libc): When doing a static link, make sure that diff --git a/elf/dl-load.c b/elf/dl-load.c index bf3e4195ad..2bc9af40c9 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -555,6 +555,33 @@ _dl_init_paths (const char *llp) } +#define LOSE(code, s) lose (code, fd, name, realname, l, s) +static void volatile +__attribute__ ((noreturn)) +lose (int code, int fd, const char *name, char *realname, struct link_map *l, + const char *msg) +{ + /* The use of `alloca' here looks ridiculous but it helps. The goal + is to avoid the function from being inlined. There is no official + way to do this so we use this trick. gcc never inlines functions + which use `alloca'. */ + int *a = alloca (sizeof (int)); + a[0] = fd; + (void) __close (a[0]); + if (l != NULL) + { + /* Remove the stillborn object from the list and free it. */ + if (l->l_prev) + l->l_prev->l_next = l->l_next; + if (l->l_next) + l->l_next->l_prev = l->l_prev; + free (l); + } + free (realname); + _dl_signal_error (code, name, msg); +} + + /* Map in the shared object NAME, actually located in REALNAME, and already opened on FD. */ @@ -565,25 +592,23 @@ struct link_map * _dl_map_object_from_fd (const char *name, int fd, char *realname, struct link_map *loader, int l_type) { + /* This is the expected ELF header. */ +#define ELF32_CLASS ELFCLASS32 +#define ELF64_CLASS ELFCLASS64 + static const unsigned char expected[EI_PAD] = + { + [EI_MAG0] = ELFMAG0, + [EI_MAG1] = ELFMAG1, + [EI_MAG2] = ELFMAG2, + [EI_MAG3] = ELFMAG3, + [EI_CLASS] = ELFW(CLASS), + [EI_DATA] = byteorder, + [EI_VERSION] = EV_CURRENT, + [EI_OSABI] = ELFOSABI_SYSV, + [EI_ABIVERSION] = 0 + }; struct link_map *l = NULL; -#define LOSE(s) lose (0, (s)) - void lose (int code, const char *msg) - { - (void) __close (fd); - if (l) - { - /* Remove the stillborn object from the list and free it. */ - if (l->l_prev) - l->l_prev->l_next = l->l_next; - if (l->l_next) - l->l_next->l_prev = l->l_prev; - free (l); - } - free (realname); - _dl_signal_error (code, name, msg); - } - inline caddr_t map_segment (ElfW(Addr) mapstart, size_t len, int prot, int fixed, off_t offset) { @@ -591,7 +616,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, fixed|MAP_COPY|MAP_FILE, fd, offset); if (mapat == MAP_FAILED) - lose (errno, "failed to map segment from shared object"); + LOSE (errno, "failed to map segment from shared object"); return mapat; } @@ -605,8 +630,8 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, struct stat st; /* Get file information. */ - if (__fstat (fd, &st) < 0) - lose (errno, "cannot stat shared object"); + if (__fxstat (_STAT_VER, fd, &st) < 0) + LOSE (errno, "cannot stat shared object"); /* Look again to see if the real name matched another already loaded. */ for (l = _dl_loaded; l; l = l->l_next) @@ -631,48 +656,52 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, /* Read the header directly. */ readbuf = alloca (_dl_pagesize); readlength = __libc_read (fd, readbuf, _dl_pagesize); - if (readlength < (ssize_t) sizeof(*header)) - lose (errno, "cannot read file data"); + if (readlength < (ssize_t) sizeof (*header)) + LOSE (errno, "cannot read file data"); header = (void *) readbuf; /* Check the header for basic validity. */ - if (*(Elf32_Word *) &header->e_ident != + if (memcmp (header->e_ident, expected, EI_PAD) != 0) + { + /* Something is wrong. */ + if (*(Elf32_Word *) &header->e_ident != #if BYTE_ORDER == LITTLE_ENDIAN - ((ELFMAG0 << (EI_MAG0 * 8)) | - (ELFMAG1 << (EI_MAG1 * 8)) | - (ELFMAG2 << (EI_MAG2 * 8)) | - (ELFMAG3 << (EI_MAG3 * 8))) + ((ELFMAG0 << (EI_MAG0 * 8)) | + (ELFMAG1 << (EI_MAG1 * 8)) | + (ELFMAG2 << (EI_MAG2 * 8)) | + (ELFMAG3 << (EI_MAG3 * 8))) #else - ((ELFMAG0 << (EI_MAG3 * 8)) | - (ELFMAG1 << (EI_MAG2 * 8)) | - (ELFMAG2 << (EI_MAG1 * 8)) | - (ELFMAG3 << (EI_MAG0 * 8))) + ((ELFMAG0 << (EI_MAG3 * 8)) | + (ELFMAG1 << (EI_MAG2 * 8)) | + (ELFMAG2 << (EI_MAG1 * 8)) | + (ELFMAG3 << (EI_MAG0 * 8))) #endif - ) - LOSE ("invalid ELF header"); -#define ELF32_CLASS ELFCLASS32 -#define ELF64_CLASS ELFCLASS64 - if (header->e_ident[EI_CLASS] != ELFW(CLASS)) - LOSE ("ELF file class not " STRING(__ELF_NATIVE_CLASS) "-bit"); - if (header->e_ident[EI_DATA] != byteorder) - LOSE ("ELF file data encoding not " byteorder_name); - if (header->e_ident[EI_VERSION] != EV_CURRENT) - LOSE ("ELF file version ident not " STRING(EV_CURRENT)); - /* XXX We should be able so set system specific versions which are - allowed here. */ - if (header->e_ident[EI_OSABI] != ELFOSABI_SYSV) - LOSE ("ELF file OS ABI not " STRING(ELFOSABI_SYSV)); - if (header->e_ident[EI_ABIVERSION] != 0) - LOSE ("ELF file ABI version not 0"); + ) + LOSE (0, "invalid ELF header"); + if (header->e_ident[EI_CLASS] != ELFW(CLASS)) + LOSE (0, "ELF file class not " STRING(__ELF_NATIVE_CLASS) "-bit"); + if (header->e_ident[EI_DATA] != byteorder) + LOSE (0, "ELF file data encoding not " byteorder_name); + if (header->e_ident[EI_VERSION] != EV_CURRENT) + LOSE (0, "ELF file version ident not " STRING(EV_CURRENT)); + /* XXX We should be able so set system specific versions which are + allowed here. */ + if (header->e_ident[EI_OSABI] != ELFOSABI_SYSV) + LOSE (0, "ELF file OS ABI not " STRING(ELFOSABI_SYSV)); + if (header->e_ident[EI_ABIVERSION] != 0) + LOSE (0, "ELF file ABI version not 0"); + LOSE (0, "internal error"); + } + if (header->e_version != EV_CURRENT) - LOSE ("ELF file version not " STRING(EV_CURRENT)); + LOSE (0, "ELF file version not " STRING(EV_CURRENT)); if (! elf_machine_matches_host (header->e_machine)) - LOSE ("ELF file machine architecture not " ELF_MACHINE_NAME); + LOSE (0, "ELF file machine architecture not " ELF_MACHINE_NAME); if (header->e_phentsize != sizeof (ElfW(Phdr))) - LOSE ("ELF file's phentsize not the expected size"); + LOSE (0, "ELF file's phentsize not the expected size"); #ifndef MAP_ANON -#define MAP_ANON 0 +# define MAP_ANON 0 if (_dl_zerofd == -1) { _dl_zerofd = _dl_sysdep_open_zero_fill (); @@ -687,7 +716,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, /* Enter the new object in the list of loaded objects. */ l = _dl_new_object (realname, name, l_type, loader); if (! l) - lose (ENOMEM, "cannot create shared object descriptor"); + LOSE (ENOMEM, "cannot create shared object descriptor"); l->l_opencount = 1; /* Extract the remaining details we need from the ELF header @@ -704,7 +733,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, phdr = alloca (maplength); __lseek (fd, SEEK_SET, header->e_phoff); if (__libc_read (fd, (void *) phdr, maplength) != maplength) - lose (errno, "cannot read file data"); + LOSE (errno, "cannot read file data"); } { @@ -717,9 +746,10 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, } loadcmds[l->l_phnum], *c; size_t nloadcmds = 0; + /* The struct is initialized to zero so this is not necessary: l->l_ld = 0; l->l_phdr = 0; - l->l_addr = 0; + l->l_addr = 0; */ for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph) switch (ph->p_type) { @@ -737,9 +767,9 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, /* A load command tells us to map in part of the file. We record the load commands and process them all later. */ if (ph->p_align % _dl_pagesize != 0) - LOSE ("ELF load command alignment not page-aligned"); + LOSE (0, "ELF load command alignment not page-aligned"); if ((ph->p_vaddr - ph->p_offset) % ph->p_align) - LOSE ("ELF load command address/offset not properly aligned"); + LOSE (0, "ELF load command address/offset not properly aligned"); { struct loadcmd *c = &loadcmds[nloadcmds++]; c->mapstart = ph->p_vaddr & ~(ph->p_align - 1); @@ -748,13 +778,34 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, c->dataend = ph->p_vaddr + ph->p_filesz; c->allocend = ph->p_vaddr + ph->p_memsz; c->mapoff = ph->p_offset & ~(ph->p_align - 1); - c->prot = 0; - if (ph->p_flags & PF_R) - c->prot |= PROT_READ; - if (ph->p_flags & PF_W) - c->prot |= PROT_WRITE; - if (ph->p_flags & PF_X) - c->prot |= PROT_EXEC; + + /* Optimize a common case. */ + if ((PF_R | PF_W | PF_X) == 7 + && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7) + { + static const unsigned char pf_to_prot[8] = + { + [0] = PROT_NONE, + [PF_R] = PROT_READ, + [PF_W] = PROT_WRITE, + [PF_R | PF_W] = PROT_READ | PROT_WRITE, + [PF_X] = PROT_EXEC, + [PF_R | PF_X] = PROT_READ | PROT_EXEC, + [PF_W | PF_X] = PROT_WRITE | PROT_EXEC, + [PF_R | PF_W | PF_X] = PROT_READ | PROT_WRITE | PROT_EXEC + }; + c->prot = pf_to_prot[ph->p_flags & (PF_R | PF_W | PF_X)]; + } + else + { + c->prot = 0; + if (ph->p_flags & PF_R) + c->prot |= PROT_READ; + if (ph->p_flags & PF_W) + c->prot |= PROT_WRITE; + if (ph->p_flags & PF_X) + c->prot |= PROT_EXEC; + } break; } } @@ -842,7 +893,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, /* Dag nab it. */ if (__mprotect ((caddr_t) (zero & ~(_dl_pagesize - 1)), _dl_pagesize, c->prot|PROT_WRITE) < 0) - lose (errno, "cannot change memory protections"); + LOSE (errno, "cannot change memory protections"); } memset ((void *) zero, 0, zeropage - zero); if ((c->prot & PROT_WRITE) == 0) @@ -858,7 +909,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED, ANONFD, 0); if (mapat == MAP_FAILED) - lose (errno, "cannot map zero-fill pages"); + LOSE (errno, "cannot map zero-fill pages"); } } @@ -880,7 +931,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, break; } if (l->l_phdr == 0) - LOSE ("program headers not contained in any loaded segment"); + LOSE (0, "program headers not contained in any loaded segment"); } else /* Adjust the PT_PHDR value by the runtime load address. */ @@ -896,7 +947,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, if (l->l_ld == 0) { if (type == ET_DYN) - LOSE ("object file has no dynamic section"); + LOSE (0, "object file has no dynamic section"); } else (ElfW(Addr)) l->l_ld += l->l_addr; @@ -951,7 +1002,7 @@ _dl_map_object_from_fd (const char *name, int fd, char *realname, (struct link_map **) malloc (sizeof (struct link_map *)); if (l->l_symbolic_searchlist.r_list == NULL) - lose (ENOMEM, "cannot create searchlist"); + LOSE (ENOMEM, "cannot create searchlist"); l->l_symbolic_searchlist.r_list[0] = l; l->l_symbolic_searchlist.r_nlist = 1; @@ -1280,9 +1331,11 @@ _dl_map_object (struct link_map *loader, const char *name, int preloaded, || (l = _dl_new_object (name_copy, name, type, loader)) == NULL) _dl_signal_error (ENOMEM, name, "cannot create shared object descriptor"); - /* We use an opencount of 0 as a sign for the faked entry. */ + /* We use an opencount of 0 as a sign for the faked entry. + Since the descriptor is initialized with zero we do not + have do this here. l->l_opencount = 0; - l->l_reserved = 0; + l->l_reserved = 0; */ l->l_buckets = &dummy_bucket; l->l_nbuckets = 1; l->l_relocated = 1; diff --git a/elf/ldsodefs.h b/elf/ldsodefs.h index 97ab955386..61652ddde4 100644 --- a/elf/ldsodefs.h +++ b/elf/ldsodefs.h @@ -1,5 +1,5 @@ /* Run-time dynamic linker data structures for loaded ELF shared objects. - Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. + Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -205,7 +205,8 @@ extern int _dl_secure; extern void _dl_signal_error (int errcode, const char *object, const char *errstring) - internal_function; + internal_function + __attribute__ ((__noreturn__)); /* Call OPERATE, catching errors from `dl_signal_error'. If there is no error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is |