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New new style program path passing

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The M1 loader now passes the program executable name directly as x2,
which is the third argument to `cosmo()`. From there it is assigned
to `__myname`.

`GetProgramExecutableName` now always returns `__myname`, and it is
`InitProgramExecutableName`’s job to set that variable if it is not
already assigned.

`InitProgramExecutableName` now dies if `issetugid()` and `__myname`
is null, pending a rework of the path-finding logic.
This commit is contained in:
Jōshin 2023-12-14 19:32:49 -05:00
parent 8dbfb77890
commit daf2156b5a
No known key found for this signature in database
7 changed files with 56 additions and 49 deletions
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34
ape/ape-m1.c
View file

@ -36,8 +36,6 @@
#include <unistd.h>
#define pagesz 16384
#define VARNAME "COSMOPOLITAN_PROGRAM_EXECUTABLE="
#define VARSIZE (sizeof(VARNAME) - 1)
/* maximum path size that cosmo can take */
#define PATHSIZE (PATH_MAX < 1024 ? PATH_MAX : 1024)
#define SYSLIB_MAGIC ('s' | 'l' << 8 | 'i' << 16 | 'b' << 24)
@ -203,11 +201,8 @@ struct PathSearcher {
unsigned long namelen;
const char *name;
const char *syspath;
char varname[VARSIZE];
char path[PATHSIZE];
};
_Static_assert(offsetof(struct PathSearcher, varname) + VARSIZE ==
offsetof(struct PathSearcher, path), "struct layout");
struct ApeLoader {
struct PathSearcher ps;
@ -563,7 +558,8 @@ static long sys_pselect(int nfds, fd_set *readfds, fd_set *writefds,
__attribute__((__noreturn__)) static void Spawn(const char *exe, int fd,
long *sp, struct ElfEhdr *e,
struct ElfPhdr *p,
struct Syslib *lib) {
struct Syslib *lib,
char *path) {
long rc;
int prot;
int flags;
@ -734,10 +730,10 @@ __attribute__((__noreturn__)) static void Spawn(const char *exe, int fd,
close(fd);
register long *x0 __asm__("x0") = sp;
register char *x2 __asm__("x2") = path;
register struct Syslib *x15 __asm__("x15") = lib;
register long x16 __asm__("x16") = e->e_entry;
__asm__ volatile("mov\tx1,#0\n\t"
"mov\tx2,#0\n\t"
"mov\tx3,#0\n\t"
"mov\tx4,#0\n\t"
"mov\tx5,#0\n\t"
@ -767,7 +763,7 @@ __attribute__((__noreturn__)) static void Spawn(const char *exe, int fd,
"mov\tx0,#0\n\t"
"br\tx16"
: /* no outputs */
: "r"(x0), "r"(x15), "r"(x16)
: "r"(x0), "r"(x2), "r"(x15), "r"(x16)
: "memory");
__builtin_unreachable();
}
@ -891,7 +887,7 @@ static const char *TryElf(struct ApeLoader *M, union ElfEhdrBuf *ebuf,
auxv[28] = 0;
/* we're now ready to load */
Spawn(exe, fd, sp, e, p, &M->lib);
Spawn(exe, fd, sp, e, p, &M->lib, M->ps.path);
}
int main(int argc, char **argv, char **envp) {
@ -901,7 +897,7 @@ int main(int argc, char **argv, char **envp) {
long *sp, *sp2, *auxv;
union ElfEhdrBuf *ebuf;
char *p, *pe, *exe, *prog,
*execfn, *shell, **varpos;
*execfn, *shell;
/* allocate loader memory in program's arg block */
n = sizeof(struct ApeLoader);
@ -965,13 +961,9 @@ int main(int argc, char **argv, char **envp) {
/* getenv("_") is close enough to at_execfn */
execfn = argc > 0 ? argv[0] : 0;
varpos = 0;
for (i = 0; envp[i]; ++i) {
if (envp[i][0] == '_' && envp[i][1] == '=') {
execfn = envp[i] + 2;
} else if (!memcmp(VARNAME, envp[i], VARSIZE)) {
assert(!varpos);
varpos = envp + i;
}
}
@ -982,7 +974,7 @@ int main(int argc, char **argv, char **envp) {
/* create new bottom of stack for spawned program
system v abi aligns this on a 16-byte boundary
grows down the alloc by poking the guard pages */
n = (auxv - sp + !varpos + AUXV_WORDS + 1) * sizeof(long);
n = (auxv - sp + AUXV_WORDS + 1) * sizeof(long);
sp2 = (long *)__builtin_alloca(n);
if ((long)sp2 & 15) ++sp2;
for (; n > 0; n -= pagesz) {
@ -991,12 +983,6 @@ int main(int argc, char **argv, char **envp) {
memmove(sp2, sp, (auxv - sp) * sizeof(long));
argv = (char **)(sp2 + 1);
envp = (char **)(sp2 + 1 + argc + 1);
if (varpos) {
varpos = (char **)((long *)varpos - sp + sp2);
} else {
varpos = envp + i++;
*(envp + i) = 0;
}
auxv = (long *)(envp + i + 1);
sp = sp2;
@ -1061,12 +1047,6 @@ int main(int argc, char **argv, char **envp) {
}
pe = ebuf->buf + rc;
/* inject program executable as first environment variable,
swapping the old first variable for it. */
memmove(M->ps.varname, VARNAME, VARSIZE);
*varpos = *envp;
*envp = M->ps.varname;
/* generate some hard random data */
if ((rc = sys_getentropy(M->rando, sizeof(M->rando))) < 0) {
Pexit(argv[0], rc, "getentropy");

38
libc/calls/getprogramexecutablename.greg.c
View file

@ -16,6 +16,7 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/atomic.h"
#include "libc/calls/calls.h"
#include "libc/calls/metalfile.internal.h"
@ -51,6 +52,11 @@ static inline int IsAlpha(int c) {
}
static inline void InitProgramExecutableNameImpl(void) {
if (__myname) {
return;
}
npassert(!issetugid()); // TODO(mrdomino): pathname security
// https://github.com/jart/cosmopolitan/issues/991
if (IsWindows()) {
int n = GetModuleFileName(0, g_prog.u.buf16, ARRAYLEN(g_prog.u.buf16));
@ -69,21 +75,20 @@ static inline void InitProgramExecutableNameImpl(void) {
g_prog.u.buf16[2] = '/';
}
tprecode16to8(g_prog.u.buf, sizeof(g_prog.u.buf), g_prog.u.buf16);
return;
goto UseBuf;
}
char c, *q;
if (IsMetal()) {
q = APE_COM_NAME;
goto CopyString;
__myname = APE_COM_NAME;
return;
}
/* the new-style loader supplies the full program path as the first
environment variable. in the spirit of Postel's Law ("be liberal
in what you accept"), we use __getenv to read it. */
/* the previous loader supplied the full program path as the first
environment variable. */
if ((q = __getenv(__envp, "COSMOPOLITAN_PROGRAM_EXECUTABLE").s)) {
strlcpy(g_prog.u.buf, q, sizeof(g_prog.u.buf));
return;
goto UseBuf;
}
// if argv[0] exists then turn it into an absolute path. we also try
@ -107,10 +112,10 @@ static inline void InitProgramExecutableNameImpl(void) {
}
}
*p = 0;
if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) return;
if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) goto UseBuf;
p = WRITE32LE(p, READ32LE(".com"));
*p = 0;
if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) return;
if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) goto UseBuf;
}
// if getenv("_") exists then use that
@ -127,7 +132,7 @@ static inline void InitProgramExecutableNameImpl(void) {
if ((got = sys_readlinkat(AT_FDCWD, "/proc/self/exe", b, n)) > 0 ||
(got = sys_readlinkat(AT_FDCWD, "/proc/curproc/file", b, n)) > 0) {
b[got] = 0;
return;
goto UseBuf;
}
if (IsFreebsd() || IsNetbsd()) {
int cmd[4];
@ -140,7 +145,7 @@ static inline void InitProgramExecutableNameImpl(void) {
}
cmd[3] = -1; // current process
if (sys_sysctl(cmd, ARRAYLEN(cmd), b, &n, 0, 0) != -1) {
return;
goto UseBuf;
}
}
@ -155,14 +160,17 @@ static inline void InitProgramExecutableNameImpl(void) {
}
}
*p = 0;
return;
goto UseBuf;
}
// if we don't even have that then empty the string
g_prog.u.buf[0] = 0;
UseBuf:
__myname = g_prog.u.buf;
}
void __InitProgramExecutableName(void) {
static void InitProgramExecutableName(void) {
int e = errno;
InitProgramExecutableNameImpl();
errno = e;
@ -172,6 +180,6 @@ void __InitProgramExecutableName(void) {
* Returns absolute path of program.
*/
char *GetProgramExecutableName(void) {
cosmo_once(&g_prog.once, __InitProgramExecutableName);
return g_prog.u.buf;
cosmo_once(&g_prog.once, InitProgramExecutableName);
return __myname;
}

2
libc/crt/crt.S
View file

@ -140,6 +140,8 @@ _start:
// should be set to zero on other platforms
mov x1,x15
// third arg (x2) is the program path passed by ape-m1.c
// switch to c code
bl cosmo
.unreachable

21
libc/nexgen32e/myname2.c Normal file
View file

@ -0,0 +1,21 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/runtime/runtime.h"
char *__myname;

3
libc/runtime/cosmo2.c
View file

@ -78,7 +78,7 @@ static const char *DecodeMagnum(const char *p, long *r) {
return *r = x, p;
}
wontreturn textstartup void cosmo(long *sp, struct Syslib *m1) {
wontreturn textstartup void cosmo(long *sp, struct Syslib *m1, char *myname) {
// get startup timestamp as early as possible
// its used by --strace and also kprintf() %T
@ -110,6 +110,7 @@ wontreturn textstartup void cosmo(long *sp, struct Syslib *m1) {
environ = envp;
program_invocation_name = argv[0];
__oldstack = (intptr_t)sp;
__myname = myname;
// detect apple m1 environment
const char *magnums;

1
libc/runtime/runtime.h
View file

@ -71,6 +71,7 @@ extern char **__argv;
extern char **__envp;
extern unsigned long *__auxv;
extern intptr_t __oldstack;
extern char *__myname;
extern uint64_t __nosync;
extern int __strace;
extern int __ftrace;

6
test/libc/calls/getprogramexecutablename_test.c
View file

@ -108,9 +108,3 @@ TEST(GetProgramExecutableName, movedSelf) {
abort();
EXITS(0);
}
void __InitProgramExecutableName(void);
BENCH(GetProgramExecutableName, bench) {
EZBENCH2("Init", donothing, __InitProgramExecutableName());
}