arg_t _execve(void)
{
/* We aren't re-entrant where this matters */
uint8_t hdr[16];
staticfast inoptr ino;
char **nargv; /* In user space */
char **nenvp; /* In user space */
struct s_argblk *abuf, *ebuf;
int argc;
uint16_t progptr;
uint16_t progload;
staticfast uint16_t top;
uint16_t bin_size; /* Will need to be bigger on some cpus */
uint16_t bss;
top = ramtop;
if (!(ino = n_open_lock(name, NULLINOPTR)))
return (-1);
if (!((getperm(ino) & OTH_EX) &&
(ino->c_node.i_mode & F_REG) &&
(ino->c_node.i_mode & (OWN_EX | OTH_EX | GRP_EX)))) {
udata.u_error = EACCES;
goto nogood;
}
setftime(ino, A_TIME);
udata.u_offset = 0;
udata.u_count = 16;
udata.u_base = hdr;
udata.u_sysio = true;
readi(ino, 0);
if (udata.u_done != 16) {
udata.u_error = ENOEXEC;
goto nogood;
}
if (!header_ok(hdr)) {
udata.u_error = ENOEXEC;
goto nogood2;
}
progload = hdr[7] << 8;
if (progload == 0)
progload = PROGLOAD;
top = *(uint16_t *)(hdr + 8);
if (top == 0) /* Legacy 'all space' binary */
top = ramtop;
else /* Requested an amount, so adjust for the base */
top += progload;
bss = *(uint16_t *)(hdr + 14);
/* Binary doesn't fit */
/* FIXME: review overflows */
bin_size = ino->c_node.i_size;
progptr = bin_size + 1024 + bss;
if (progload < PROGLOAD || top - progload < progptr || progptr < bin_size) {
udata.u_error = ENOMEM;
goto nogood2;
}
udata.u_ptab->p_status = P_NOSLEEP;
/* If we made pagemap_realloc keep hold of some defined area we
could in theory just move the arguments up or down as part of
the process - that would save us all this hassle but replace it
with new hassle */
/* Gather the arguments, and put them in temporary buffers. */
abuf = (struct s_argblk *) tmpbuf();
/* Put environment in another buffer. */
ebuf = (struct s_argblk *) tmpbuf();
/* Read args and environment from process memory */
if (rargs(argv, abuf) || rargs(envp, ebuf))
goto nogood3; /* SN */
/* This must be the last test as it makes changes if it works */
/* FIXME: once we sort out chmem we can make stack and data
two elements. We never allocate 'code' as there is no split I/D */
/* This is only safe from deadlocks providing pagemap_realloc doesn't
sleep */
if (pagemap_realloc(0, top - MAPBASE, 0))
goto nogood3;
/* From this point on we are commmited to the exec() completing */
/* Core dump and ptrace permission logic */
#ifdef CONFIG_LEVEL_2
/* Q: should uid == 0 mean we always allow core */
if ((!(getperm(ino) & OTH_RD)) ||
(ino->c_node.i_mode & (SET_UID | SET_GID)))
udata.u_flags |= U_FLAG_NOCORE;
else
udata.u_flags &= ~U_FLAG_NOCORE;
#endif
udata.u_top = top;
udata.u_ptab->p_top = top;
/* setuid, setgid if executable requires it */
if (ino->c_node.i_mode & SET_UID)
udata.u_euid = ino->c_node.i_uid;
if (ino->c_node.i_mode & SET_GID)
udata.u_egid = ino->c_node.i_gid;
/* FIXME: In the execve case we may on some platforms have space
below PROGLOAD to clear... */
/* We are definitely going to succeed with the exec,
* so we can start writing over the old program
*/
uput(hdr, (uint8_t *)progload, 16);
/* At this point, we are committed to reading in and
* executing the program. This call must not block. */
close_on_exec();
/*
* Read in the rest of the program, block by block. We rely upon
* the optimization path in readi to spot this is a big move to user
* space and move it directly.
*/
progptr = progload + 16;
if (bin_size > 16) {
bin_size -= 16;
udata.u_base = (uint8_t *)progptr; /* We copied the first block already */
udata.u_count = bin_size;
udata.u_sysio = false;
readi(ino, 0);
if (udata.u_done != bin_size)
goto nogood4;
progptr += bin_size;
}
/* Wipe the memory in the BSS. We don't wipe the memory above
that on 8bit boxes, but defer it to brk/sbrk() */
uzero((uint8_t *)progptr, bss);
/* Set initial break for program */
udata.u_break = (int)ALIGNUP(progptr + bss);
/* Turn off caught signals */
memset(udata.u_sigvec, 0, sizeof(udata.u_sigvec));
// place the arguments, environment and stack at the top of userspace memory,
// Write back the arguments and the environment
nargv = wargs(((char *) top - 2), abuf, &argc);
nenvp = wargs((char *) (nargv), ebuf, NULL);
// Fill in udata.u_name with program invocation name
uget((void *) ugetw(nargv), udata.u_name, 8);
memcpy(udata.u_ptab->p_name, udata.u_name, 8);
tmpfree(abuf);
tmpfree(ebuf);
i_deref(ino);
/* Shove argc and the address of argv just below envp
FIXME: should flip them in crt0.S of app for R2L setups
so we can get rid of the ifdefs */
#ifdef CONFIG_CALL_R2L /* Arguments are stacked the 'wrong' way around */
uputw((uint16_t) nargv, nenvp - 2);
uputw((uint16_t) argc, nenvp - 1);
#else
uputw((uint16_t) nargv, nenvp - 1);
uputw((uint16_t) argc, nenvp - 2);
#endif
/* Set stack pointer for the program */
udata.u_isp = nenvp - 2;
/* Start execution (never returns) */
udata.u_ptab->p_status = P_RUNNING;
doexec(progload);
/* tidy up in various failure modes */
nogood4:
/* Must not run userspace */
ssig(udata.u_ptab, SIGKILL);
nogood3:
udata.u_ptab->p_status = P_RUNNING;
tmpfree(abuf);
tmpfree(ebuf);
nogood2:
nogood:
i_unlock_deref(ino);
return (-1);
}
arg_t _execve(void)
{
/* Not ideal on stack */
struct binfmt_flat binflat;
inoptr ino;
char **nargv; /* In user space */
char **nenvp; /* In user space */
struct s_argblk *abuf, *ebuf;
int argc;
uint32_t bin_size; /* Will need to be bigger on some cpus */
uaddr_t progbase, top;
uaddr_t go;
uint32_t true_brk;
if (!(ino = n_open_lock(name, NULLINOPTR)))
return (-1);
if (!((getperm(ino) & OTH_EX) &&
(ino->c_node.i_mode & F_REG) &&
(ino->c_node.i_mode & (OWN_EX | OTH_EX | GRP_EX)))) {
udata.u_error = EACCES;
goto nogood;
}
setftime(ino, A_TIME);
udata.u_offset = 0;
udata.u_count = sizeof(struct binfmt_flat);
udata.u_base = (void *)&binflat;
udata.u_sysio = true;
readi(ino, 0);
if (udata.u_done != sizeof(struct binfmt_flat)) {
udata.u_error = ENOEXEC;
goto nogood;
}
/* FIXME: ugly - save this as valid_hdr modifies it */
true_brk = binflat.bss_end;
/* Hard coded for our 68K format. We don't quite use the ucLinux
names, we don't want to load a ucLinux binary in error! */
if (memcmp(binflat.magic, "bFLT", 4) || !valid_hdr(ino, &binflat)) {
udata.u_error = ENOEXEC;
goto nogood2;
}
/* Memory needed */
bin_size = binflat.bss_end + binflat.stack_size;
/* Overflow ? */
if (bin_size < binflat.bss_end) {
udata.u_error = ENOEXEC;
goto nogood2;
}
/* Gather the arguments, and put them in temporary buffers. */
abuf = (struct s_argblk *) tmpbuf();
/* Put environment in another buffer. */
ebuf = (struct s_argblk *) tmpbuf();
/* Read args and environment from process memory */
if (rargs(argv, abuf) || rargs(envp, ebuf))
goto nogood3;
/* This must be the last test as it makes changes if it works */
/* FIXME: need to update this to support split code/data and to fix
stack handling nicely */
/* FIXME: ENOMEM fix needs to go to 16bit ? */
if ((udata.u_error = pagemap_realloc(0, bin_size, 0)) != 0)
goto nogood3;
/* Core dump and ptrace permission logic */
#ifdef CONFIG_LEVEL_2
/* Q: should uid == 0 mean we always allow core */
if ((!(getperm(ino) & OTH_RD)) ||
(ino->c_node.i_mode & (SET_UID | SET_GID)))
udata.u_flags |= U_FLAG_NOCORE;
else
udata.u_flags &= ~U_FLAG_NOCORE;
#endif
udata.u_codebase = progbase = pagemap_base();
/* From this point on we are commmited to the exec() completing
so we can start writing over the old program */
uput(&binflat, (uint8_t *)progbase, sizeof(struct binfmt_flat));
/* setuid, setgid if executable requires it */
if (ino->c_node.i_mode & SET_UID)
udata.u_euid = ino->c_node.i_uid;
if (ino->c_node.i_mode & SET_GID)
udata.u_egid = ino->c_node.i_gid;
top = progbase + bin_size;
udata.u_top = top;
udata.u_ptab->p_top = top;
// kprintf("user space at %p\n", progbase);
// kprintf("top at %p\n", progbase + bin_size);
bin_size = binflat.reloc_start + 4 * binflat.reloc_count;
go = (uint32_t)progbase + binflat.entry;
close_on_exec();
/*
* Read in the rest of the program, block by block. We rely upon
* the optimization path in readi to spot this is a big move to user
* space and move it directly.
*/
if (bin_size > sizeof(struct binfmt_flat)) {
/* We copied the header already */
bin_size -= sizeof(struct binfmt_flat);
udata.u_base = (uint8_t *)progbase +
sizeof(struct binfmt_flat);
udata.u_count = bin_size;
udata.u_sysio = false;
readi(ino, 0);
if (udata.u_done != bin_size)
goto nogood4;
}
/* Header isn't counted in relocations */
relocate(&binflat, progbase, bin_size);
/* This may wipe the relocations */
uzero((uint8_t *)progbase + binflat.data_end,
binflat.bss_end - binflat.data_end + binflat.stack_size);
/* Use of brk eats into the stack allocation */
/* Use the temporary we saved (hack) as we mangled bss_end */
udata.u_break = udata.u_codebase + true_brk;
/* Turn off caught signals */
memset(udata.u_sigvec, 0, sizeof(udata.u_sigvec));
/* place the arguments, environment and stack at the top of userspace memory. */
/* Write back the arguments and the environment */
nargv = wargs(((char *) top - 4), abuf, &argc);
nenvp = wargs((char *) (nargv), ebuf, NULL);
/* Fill in udata.u_name with Program invocation name */
uget((void *) ugetl(nargv, NULL), udata.u_name, 8);
memcpy(udata.u_ptab->p_name, udata.u_name, 8);
tmpfree(abuf);
tmpfree(ebuf);
i_unlock_deref(ino);
/* Shove argc and the address of argv just below envp */
uputl((uint32_t) nargv, nenvp - 1);
uputl((uint32_t) argc, nenvp - 2);
// Set stack pointer for the program
udata.u_isp = nenvp - 2;
/*
* Sort of - it's a good way to deal with all the stupidity of
* random 68K platforms we will have to handle, and a nice place
* to stuff the signal trampoline 8)
*/
install_vdso();
// kprintf("Go = %p ISP = %p\n", go, udata.u_isp);
doexec(go);
nogood4:
/* Must not run userspace */
ssig(udata.u_ptab, SIGKILL);
nogood3:
tmpfree(abuf);
tmpfree(ebuf);
nogood2:
nogood:
i_unlock_deref(ino);
return (-1);
}
