cosmopolitan/libc/log/commandvenv.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

62 lines
3.2 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/intrin/safemacros.internal.h"
#include "libc/limits.h"
#include "libc/log/log.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/ok.h"
/**
* Finds full executable path in overridable way.
*
* This is a higher level version of the commandv() function. Programs
* that spawn subprocesses can use this function to determine the path
* at startup. Here's an example how you could use it:
*
* if ((strace = commandvenv("STRACE", "strace"))) {
* strace = strdup(strace);
* } else {
* fprintf(stderr, "error: please install strace\n");
* exit(1);
* }
*
* @param var is environment variable which may be used to override
* PATH search, and it can force a NULL result if it's empty
* @param cmd is name of program, which is returned asap if it's an
* absolute path
* @return pointer to exe path string, or NULL if it couldn't be found
* or the environment variable was empty; noting that the caller
* should copy this string before saving it
*/
const char *commandvenv(const char *var, const char *cmd) {
const char *exepath;
static char pathbuf[PATH_MAX];
if (*cmd == '/' || *cmd == '\\') return cmd;
if ((exepath = getenv(var))) {
if (isempty(exepath)) return NULL;
if (access(exepath, X_OK) != -1) {
return exepath;
} else {
return NULL;
}
}
return commandv(cmd, pathbuf, sizeof(pathbuf));
}