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Simplify the code to allocate stack for auxv, argv[], and environment vectors.

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Remove auxarg_size as it was only used once right after a confusing
assignment in each of the variants of exec_copyout_strings().

Reviewed by:	emaste
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D15123
This commit is contained in:
John Baldwin 2018-04-19 16:00:34 +00:00
parent b3e85e7a79
commit 73c8686e91
6 changed files with 55 additions and 108 deletions
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32
sys/amd64/linux/linux_sysvec.c
View File

@ -331,32 +331,22 @@ linux_copyout_strings(struct image_params *imgp)
roundup(sizeof(canary), sizeof(char *));
copyout(canary, (void *)imgp->canary, sizeof(canary));
/* If we have a valid auxargs ptr, prepare some room on the stack. */
vectp = (char **)destp;
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
* Allocate room on the stack for the ELF auxargs
* array. It has LINUX_AT_COUNT entries.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
(LINUX_AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (char **)(destp - (imgp->args->argc +
imgp->args->envc + 2 + imgp->auxarg_size) * sizeof(char *));
} else {
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (char **)(destp - (imgp->args->argc +
imgp->args->envc + 2) * sizeof(char *));
vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf64_Auxinfo),
sizeof(*vectp));
}
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/* vectp also becomes our initial stack base. */
stack_base = (register_t *)vectp;

32
sys/amd64/linux32/linux32_sysvec.c
View File

@ -793,32 +793,22 @@ linux_copyout_strings(struct image_params *imgp)
roundup(sizeof(canary), sizeof(char *));
copyout(canary, (void *)imgp->canary, sizeof(canary));
/* If we have a valid auxargs ptr, prepare some room on the stack. */
vectp = (uint32_t *)destp;
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
* Allocate room on the stack for the ELF auxargs
* array. It has LINUX_AT_COUNT entries.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
(LINUX_AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (u_int32_t *) (destp - (imgp->args->argc +
imgp->args->envc + 2 + imgp->auxarg_size) *
sizeof(u_int32_t));
} else {
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (u_int32_t *)(destp - (imgp->args->argc +
imgp->args->envc + 2) * sizeof(u_int32_t));
vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf32_Auxinfo),
sizeof(*vectp));
}
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/* vectp also becomes our initial stack base. */
stack_base = vectp;

34
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -3180,34 +3180,22 @@ freebsd32_copyout_strings(struct image_params *imgp)
destp -= ARG_MAX - imgp->args->stringspace;
destp = rounddown2(destp, sizeof(uint32_t));
/*
* If we have a valid auxargs ptr, prepare some room
* on the stack.
*/
vectp = (uint32_t *)destp;
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
* Allocate room on the stack for the ELF auxargs
* array. It has up to AT_COUNT entries.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size
: (AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (u_int32_t *) (destp - (imgp->args->argc +
imgp->args->envc + 2 + imgp->auxarg_size + execpath_len) *
sizeof(u_int32_t));
} else {
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (u_int32_t *)(destp - (imgp->args->argc +
imgp->args->envc + 2) * sizeof(u_int32_t));
vectp -= howmany(AT_COUNT * sizeof(Elf32_Auxinfo),
sizeof(*vectp));
}
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/*
* vectp also becomes our initial stack base
*/

30
sys/i386/linux/linux_sysvec.c
View File

@ -309,30 +309,22 @@ linux_copyout_strings(struct image_params *imgp)
roundup(sizeof(canary), sizeof(char *));
copyout(canary, (void *)imgp->canary, sizeof(canary));
/* If we have a valid auxargs ptr, prepare some room on the stack. */
vectp = (char **)destp;
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
* Allocate room on the stack for the ELF auxargs
* array. It has LINUX_AT_COUNT entries.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
(LINUX_AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (char **)(destp - (imgp->args->argc +
imgp->args->envc + 2 + imgp->auxarg_size) * sizeof(char *));
} else {
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc + 2) *
sizeof(char *));
vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf32_Auxinfo),
sizeof(*vectp));
}
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/* vectp also becomes our initial stack base. */
stack_base = (register_t *)vectp;

34
sys/kern/kern_exec.c
View File

@ -1537,34 +1537,22 @@ exec_copyout_strings(struct image_params *imgp)
destp -= ARG_MAX - imgp->args->stringspace;
destp = rounddown2(destp, sizeof(void *));
/*
* If we have a valid auxargs ptr, prepare some room
* on the stack.
*/
vectp = (char **)destp;
if (imgp->auxargs) {
/*
* 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
* lower compatibility.
* Allocate room on the stack for the ELF auxargs
* array. It has up to AT_COUNT entries.
*/
imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
(AT_COUNT * 2);
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets,and imgp->auxarg_size is room
* for argument of Runtime loader.
*/
vectp = (char **)(destp - (imgp->args->argc +
imgp->args->envc + 2 + imgp->auxarg_size)
* sizeof(char *));
} else {
/*
* The '+ 2' is for the null pointers at the end of each of
* the arg and env vector sets
*/
vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc
+ 2) * sizeof(char *));
vectp -= howmany(AT_COUNT * sizeof(Elf_Auxinfo),
sizeof(*vectp));
}
/*
* Allocate room for the argv[] and env vectors including the
* terminating NULL pointers.
*/
vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
/*
* vectp also becomes our initial stack base
*/

1
sys/sys/imgact.h
View File

@ -75,7 +75,6 @@ struct image_params {
void *auxargs; /* ELF Auxinfo structure pointer */
struct sf_buf *firstpage; /* first page that we mapped */
unsigned long ps_strings; /* PS_STRINGS for BSD/OS binaries */
size_t auxarg_size;
struct image_args *args; /* system call arguments */
struct sysentvec *sysent; /* system entry vector */
char *execpath;