cosmopolitan/libc/log/commandvenv.c
Justine Tunney f531acc8f9
Make improvements
- Invent openatemp() API
- Invent O_UNLINK open flag
- Introduce getenv_secure() API
- Remove `git pull` from cosmocc
- Fix utimes() when path is NULL
- Fix mktemp() to never return NULL
- Fix utimensat() UTIME_OMIT on XNU
- Improve utimensat() code for RHEL5
- Turn `argv[0]` C:/ to /C/ on Windows
- Introduce tmpnam() and tmpnam_r() APIs
- Fix more const issues with internal APIs
- Permit utimes() on WIN32 in O_RDONLY mode
- Fix fdopendir() to check fd is a directory
- Fix recent crash regression in landlock make
- Fix futimens(AT_FDCWD, NULL) to return EBADF
- Use workaround so `make -j` doesn't fork bomb
- Rename dontdiscard to __wur (just like glibc)
- Fix st_size for WIN32 symlinks containing UTF-8
- Introduce stdio ext APIs needed by GNU coreutils
- Fix lstat() on WIN32 for symlinks to directories
- Move some constants from normalize.inc to limits.h
- Fix segv with memchr() and memcmp() overlapping page
- Implement POSIX fflush() behavior for reader streams
- Implement AT_SYMLINK_NOFOLLOW for utimensat() on WIN32
- Don't change read-only status of existing files on WIN32
- Correctly handle `0x[^[:xdigit:]]` case in strtol() functions
2023-09-06 12:34:59 -07:00

62 lines
3.2 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net 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));
}