qemu/linux-user/linuxload.c
Richard Henderson 60f1c8017a linux-user: Clean up arg_start/arg_end confusion
We had two sets of variables: arg_start/arg_end, and
arg_strings/env_strings.  In linuxload.c, we set the
first pair to the bounds of the argv strings, but in
elfload.c, we set the first pair to the bounds of the
argv pointers and the second pair to the bounds of
the argv strings.

Remove arg_start/arg_end, replacing them with the standard
argc/argv/envc/envp values.  Retain arg_strings/env_strings
with the meaning we were using in elfload.c.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/714
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220427025129.160184-1-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2022-05-23 08:15:19 +02:00

176 lines
4.2 KiB
C

/* Code for loading Linux executables. Mostly linux kernel code. */
#include "qemu/osdep.h"
#include "qemu.h"
#include "user-internals.h"
#include "loader.h"
#define NGROUPS 32
/* ??? This should really be somewhere else. */
abi_long memcpy_to_target(abi_ulong dest, const void *src, unsigned long len)
{
void *host_ptr;
host_ptr = lock_user(VERIFY_WRITE, dest, len, 0);
if (!host_ptr) {
return -TARGET_EFAULT;
}
memcpy(host_ptr, src, len);
unlock_user(host_ptr, dest, 1);
return 0;
}
static int count(char **vec)
{
int i;
for (i = 0; *vec; i++) {
vec++;
}
return i;
}
static int prepare_binprm(struct linux_binprm *bprm)
{
struct stat st;
int mode;
int retval;
if (fstat(bprm->fd, &st) < 0) {
return -errno;
}
mode = st.st_mode;
if (!S_ISREG(mode)) { /* Must be regular file */
return -EACCES;
}
if (!(mode & 0111)) { /* Must have at least one execute bit set */
return -EACCES;
}
bprm->e_uid = geteuid();
bprm->e_gid = getegid();
/* Set-uid? */
if (mode & S_ISUID) {
bprm->e_uid = st.st_uid;
}
/* Set-gid? */
/*
* If setgid is set but no group execute bit then this
* is a candidate for mandatory locking, not a setgid
* executable.
*/
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
bprm->e_gid = st.st_gid;
}
retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
if (retval < 0) {
perror("prepare_binprm");
exit(-1);
}
if (retval < BPRM_BUF_SIZE) {
/* Make sure the rest of the loader won't read garbage. */
memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
}
return retval;
}
/* Construct the envp and argv tables on the target stack. */
abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
abi_ulong stringp, int push_ptr)
{
TaskState *ts = (TaskState *)thread_cpu->opaque;
int n = sizeof(abi_ulong);
abi_ulong envp;
abi_ulong argv;
sp -= (envc + 1) * n;
envp = sp;
sp -= (argc + 1) * n;
argv = sp;
ts->info->envp = envp;
ts->info->envc = envc;
ts->info->argv = argv;
ts->info->argc = argc;
if (push_ptr) {
/* FIXME - handle put_user() failures */
sp -= n;
put_user_ual(envp, sp);
sp -= n;
put_user_ual(argv, sp);
}
sp -= n;
/* FIXME - handle put_user() failures */
put_user_ual(argc, sp);
ts->info->arg_strings = stringp;
while (argc-- > 0) {
/* FIXME - handle put_user() failures */
put_user_ual(stringp, argv);
argv += n;
stringp += target_strlen(stringp) + 1;
}
/* FIXME - handle put_user() failures */
put_user_ual(0, argv);
ts->info->env_strings = stringp;
while (envc-- > 0) {
/* FIXME - handle put_user() failures */
put_user_ual(stringp, envp);
envp += n;
stringp += target_strlen(stringp) + 1;
}
/* FIXME - handle put_user() failures */
put_user_ual(0, envp);
return sp;
}
int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
struct target_pt_regs *regs, struct image_info *infop,
struct linux_binprm *bprm)
{
int retval;
bprm->fd = fdexec;
bprm->filename = (char *)filename;
bprm->argc = count(argv);
bprm->argv = argv;
bprm->envc = count(envp);
bprm->envp = envp;
retval = prepare_binprm(bprm);
if (retval >= 0) {
if (bprm->buf[0] == 0x7f
&& bprm->buf[1] == 'E'
&& bprm->buf[2] == 'L'
&& bprm->buf[3] == 'F') {
retval = load_elf_binary(bprm, infop);
#if defined(TARGET_HAS_BFLT)
} else if (bprm->buf[0] == 'b'
&& bprm->buf[1] == 'F'
&& bprm->buf[2] == 'L'
&& bprm->buf[3] == 'T') {
retval = load_flt_binary(bprm, infop);
#endif
} else {
return -ENOEXEC;
}
}
if (retval >= 0) {
/* success. Initialize important registers */
do_init_thread(regs, infop);
return retval;
}
return retval;
}