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elf: inline lose for error handling

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_dl_map_object_from_fd has complex error handling with cleanups.
It was managed by a separate function to avoid code bloat at
every failure case, but since the code was changed to use gotos
there is no longer such code bloat from inlining.

Maintaining a separate error handling function is harder as it
needs to access local state which has to be passed down. And the
same lose function was used in open_verify which is error prone.

The goto labels are changed since there is no longer a call.
The new code generates slightly smaller binary.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Szabolcs Nagy 2020-11-24 11:08:33 +00:00
parent e182654151
commit cb5648b00f
1 changed files with 39 additions and 48 deletions
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87
elf/dl-load.c
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@ -838,30 +838,6 @@ _dl_init_paths (const char *llp, const char *source,
}
static void
__attribute__ ((noreturn, noinline))
lose (int code, int fd, const char *name, char *realname, struct link_map *l,
const char *msg, struct r_debug *r, Lmid_t nsid)
{
/* The file might already be closed. */
if (fd != -1)
(void) __close_nocancel (fd);
if (l != NULL && l->l_origin != (char *) -1l)
free ((char *) l->l_origin);
free (l);
free (realname);
if (r != NULL)
{
r->r_state = RT_CONSISTENT;
_dl_debug_state ();
LIBC_PROBE (map_failed, 2, nsid, r);
}
_dl_signal_error (code, name, NULL, msg);
}
/* Process PT_GNU_PROPERTY program header PH in module L after
PT_LOAD segments are mapped. Only one NT_GNU_PROPERTY_TYPE_0
note is handled which contains processor specific properties.
@ -973,11 +949,25 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
if (__glibc_unlikely (!_dl_get_file_id (fd, &id)))
{
errstring = N_("cannot stat shared object");
call_lose_errno:
lose_errno:
errval = errno;
call_lose:
lose (errval, fd, name, realname, l, errstring,
make_consistent ? r : NULL, nsid);
lose:
/* The file might already be closed. */
if (fd != -1)
__close_nocancel (fd);
if (l != NULL && l->l_origin != (char *) -1l)
free ((char *) l->l_origin);
free (l);
free (realname);
if (make_consistent && r != NULL)
{
r->r_state = RT_CONSISTENT;
_dl_debug_state ();
LIBC_PROBE (map_failed, 2, nsid, r);
}
_dl_signal_error (errval, name, NULL, errstring);
}
/* Look again to see if the real name matched another already loaded. */
@ -1084,7 +1074,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
fail_new:
#endif
errstring = N_("cannot create shared object descriptor");
goto call_lose_errno;
goto lose_errno;
}
/* Extract the remaining details we need from the ELF header
@ -1103,7 +1093,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
header->e_phoff) != maplength)
{
errstring = N_("cannot read file data");
goto call_lose_errno;
goto lose_errno;
}
}
@ -1149,14 +1139,14 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
if (__glibc_unlikely ((ph->p_align & (GLRO(dl_pagesize) - 1)) != 0))
{
errstring = N_("ELF load command alignment not page-aligned");
goto call_lose;
goto lose;
}
if (__glibc_unlikely (((ph->p_vaddr - ph->p_offset)
& (ph->p_align - 1)) != 0))
{
errstring
= N_("ELF load command address/offset not properly aligned");
goto call_lose;
goto lose;
}
struct loadcmd *c = &loadcmds[nloadcmds++];
@ -1235,7 +1225,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
another error below. But we don't want to go through the
calculations below using NLOADCMDS - 1. */
errstring = N_("object file has no loadable segments");
goto call_lose;
goto lose;
}
/* dlopen of an executable is not valid because it is not possible
@ -1248,7 +1238,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
/* This object is loaded at a fixed address. This must never
happen for objects loaded with dlopen. */
errstring = N_("cannot dynamically load executable");
goto call_lose;
goto lose;
}
/* Length of the sections to be loaded. */
@ -1261,7 +1251,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
maplength, has_holes, loader);
if (__glibc_unlikely (errstring != NULL))
goto call_lose;
goto lose;
}
if (l->l_ld == 0)
@ -1269,7 +1259,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
if (__glibc_unlikely (type == ET_DYN))
{
errstring = N_("object file has no dynamic section");
goto call_lose;
goto lose;
}
}
else
@ -1298,7 +1288,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
= N_("cannot dynamically load position-independent executable");
else
errstring = N_("shared object cannot be dlopen()ed");
goto call_lose;
goto lose;
}
if (l->l_phdr == NULL)
@ -1311,7 +1301,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
if (newp == NULL)
{
errstring = N_("cannot allocate memory for program header");
goto call_lose_errno;
goto lose_errno;
}
l->l_phdr = memcpy (newp, phdr,
@ -1344,7 +1334,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
if (__mprotect ((void *) p, s, PROT_READ|PROT_WRITE) < 0)
{
errstring = N_("cannot change memory protections");
goto call_lose_errno;
goto lose_errno;
}
__stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
__mprotect ((void *) p, s, PROT_READ);
@ -1365,7 +1355,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
{
errstring = N_("\
cannot enable executable stack as shared object requires");
goto call_lose;
goto lose;
}
}
@ -1392,7 +1382,7 @@ cannot enable executable stack as shared object requires");
if (__glibc_unlikely (__close_nocancel (fd) != 0))
{
errstring = N_("cannot close file descriptor");
goto call_lose_errno;
goto lose_errno;
}
/* Signal that we closed the file. */
fd = -1;
@ -1671,14 +1661,15 @@ open_verify (const char *name, int fd,
errval = errno;
errstring = (errval == 0
? N_("file too short") : N_("cannot read file data"));
call_lose:
lose:
if (free_name)
{
char *realname = (char *) name;
name = strdupa (realname);
free (realname);
}
lose (errval, fd, name, NULL, NULL, errstring, NULL, 0);
__close_nocancel (fd);
_dl_signal_error (errval, name, NULL, errstring);
}
/* See whether the ELF header is what we expect. */
@ -1738,13 +1729,13 @@ open_verify (const char *name, int fd,
/* Otherwise we don't know what went wrong. */
errstring = N_("internal error");
goto call_lose;
goto lose;
}
if (__glibc_unlikely (ehdr->e_version != EV_CURRENT))
{
errstring = N_("ELF file version does not match current one");
goto call_lose;
goto lose;
}
if (! __glibc_likely (elf_machine_matches_host (ehdr)))
goto close_and_out;
@ -1752,12 +1743,12 @@ open_verify (const char *name, int fd,
&& ehdr->e_type != ET_EXEC))
{
errstring = N_("only ET_DYN and ET_EXEC can be loaded");
goto call_lose;
goto lose;
}
else if (__glibc_unlikely (ehdr->e_phentsize != sizeof (ElfW(Phdr))))
{
errstring = N_("ELF file's phentsize not the expected size");
goto call_lose;
goto lose;
}
maplength = ehdr->e_phnum * sizeof (ElfW(Phdr));
@ -1772,7 +1763,7 @@ open_verify (const char *name, int fd,
read_error:
errval = errno;
errstring = N_("cannot read file data");
goto call_lose;
goto lose;
}
}