cosmopolitan/libc/proc/execvpe.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

83 lines
3.7 KiB
C

/*-*- 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 2020 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/calls/calls.h"
#include "libc/dce.h"
#include "libc/intrin/asan.internal.h"
#include "libc/limits.h"
#include "libc/mem/alloca.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
/**
* Executes program, with path environment search.
*
* This function is a wrapper of the execve() system call that does path
* resolution. The `PATH` environment variable is taken from your global
* `environ` rather than the `envp` argument.
*
* @param prog is the program to launch
* @param argv is [file,argv₁..argvₙ₋₁,NULL]
* @param envp is ["key=val",...,NULL]
* @return doesn't return on success, otherwise -1 w/ errno
* @asyncsignalsafe
* @vforksafe
*/
int execvpe(const char *prog, char *const argv[], char *const *envp) {
size_t i;
char *exe, **argv2;
char pathbuf[PATH_MAX];
// validate memory
if (IsAsan() &&
(!__asan_is_valid_str(prog) || !__asan_is_valid_strlist(argv))) {
return efault();
}
if (strchr(prog, '/')) {
return execve(prog, argv, envp);
}
// resolve path of executable
if (!(exe = commandv(prog, pathbuf, sizeof(pathbuf)))) {
return -1;
}
// change argv[0] to resolved path if it's ambiguous
// otherwise the program won't have much luck finding itself
if (argv[0] && *prog != '/' && *exe == '/' && !strcmp(prog, argv[0])) {
for (i = 0; argv[i++];) (void)0;
#pragma GCC push_options
#pragma GCC diagnostic ignored "-Walloca-larger-than="
int nbytes = i * sizeof(*argv);
if (__get_safe_size(nbytes, 4096) < nbytes) return enomem();
argv2 = alloca(nbytes);
CheckLargeStackAllocation(argv2, nbytes);
#pragma GCC pop_options
memcpy(argv2, argv, nbytes);
argv2[0] = exe;
argv = argv2;
}
// execute program
// tail call shouldn't be possible
return execve(exe, argv, envp);
}