mirror of
https://github.com/jart/cosmopolitan.git
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7faffde303
Missed this when changing the code back to be like the old version. com is now a parameter. The only plausible way to trigger this would be to pass a loader pathname close to MAX_PATH characters long, and then remove that path prior to the first sys_faccessat.
227 lines
7.1 KiB
C
227 lines
7.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/atomic.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/metalfile.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/cosmo.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/fmt/libgen.h"
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#include "libc/intrin/getenv.internal.h"
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#include "libc/serialize.h"
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#include "libc/limits.h"
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#include "libc/macros.internal.h"
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#include "libc/nt/runtime.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/at.h"
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#include "libc/sysv/consts/ok.h"
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#define CTL_KERN 1
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#define KERN_PROC 14
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#define KERN_PROC_PATHNAME_FREEBSD 12
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#define KERN_PROC_PATHNAME_NETBSD 5
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static struct {
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atomic_uint once;
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union {
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char buf[PATH_MAX];
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char16_t buf16[PATH_MAX / 2];
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} u;
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} g_prog;
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static inline int IsAlpha(int c) {
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return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
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}
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static inline int AllNumDot(const char *s) {
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while (true) {
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switch (*s++) {
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default: return 0;
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case 0: return 1;
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9': case '.':
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; /* continue */
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}
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}
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}
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// old loaders do not pass __program_executable_name, so we need to
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// check for them when we use KERN_PROC_PATHNAME et al.
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static int OldApeLoader(char *s) {
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char *b;
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return !strcmp(s, "/usr/bin/ape") ||
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(!strncmp((b = basename(s)), ".ape-", 5) &&
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AllNumDot(b + 5));
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}
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// if q exists then turn it into an absolute path. we also try adding
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// a .com suffix since the ape auto-appends it when resolving
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static int TryPath(const char *q, int com) {
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char c, *p, *e;
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if (!q) return 0;
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p = g_prog.u.buf;
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e = p + sizeof(g_prog.u.buf);
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if (*q != '/') {
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if (q[0] == '.' && q[1] == '/') {
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q += 2;
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}
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int got = __getcwd(p, e - p - 1 /* '/' */ - com * 4);
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if (got != -1) {
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p += got - 1;
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*p++ = '/';
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}
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}
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while ((c = *q++)) {
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if (p + com * 4 + 1 /* nul */ < e) {
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*p++ = c;
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} else {
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return 0;
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}
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}
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*p = 0;
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if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) return 1;
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if (!com) return 0;
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p = WRITE32LE(p, READ32LE(".com"));
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*p = 0;
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if (!sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0)) return 1;
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return 0;
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}
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static inline void InitProgramExecutableNameImpl(void) {
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size_t n;
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ssize_t got;
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char c, *q, *b;
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if (IsWindows()) {
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int n = GetModuleFileName(0, g_prog.u.buf16, ARRAYLEN(g_prog.u.buf16));
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for (int i = 0; i < n; ++i) {
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// turn c:\foo\bar into c:/foo/bar
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if (g_prog.u.buf16[i] == '\\') {
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g_prog.u.buf16[i] = '/';
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}
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}
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if (IsAlpha(g_prog.u.buf16[0]) && //
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g_prog.u.buf16[1] == ':' && //
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g_prog.u.buf16[2] == '/') {
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// turn c:/... into /c/...
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g_prog.u.buf16[1] = g_prog.u.buf16[0];
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g_prog.u.buf16[0] = '/';
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g_prog.u.buf16[2] = '/';
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}
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tprecode16to8(g_prog.u.buf, sizeof(g_prog.u.buf), g_prog.u.buf16);
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goto UseBuf;
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}
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if (IsMetal()) {
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__program_executable_name = APE_COM_NAME;
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return;
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}
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// loader passed us a path. it may be relative.
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if (__program_executable_name) {
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if (*__program_executable_name == '/') {
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return;
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}
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if (TryPath(__program_executable_name, 0)) {
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goto UseBuf;
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}
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/* if TryPath fails, it probably failed because getcwd() was too long.
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we are out of options now; KERN_PROC_PATHNAME et al will return the
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name of the loader not the binary, and argv et al will at best have
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the same problem. just use the relative path we got from the loader
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as-is, and accept that if we chdir then things will break. */
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return;
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}
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b = g_prog.u.buf;
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n = sizeof(g_prog.u.buf) - 1;
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if (IsFreebsd() || IsNetbsd()) {
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int cmd[4];
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cmd[0] = CTL_KERN;
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cmd[1] = KERN_PROC;
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if (IsFreebsd()) {
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cmd[2] = KERN_PROC_PATHNAME_FREEBSD;
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} else {
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cmd[2] = KERN_PROC_PATHNAME_NETBSD;
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}
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cmd[3] = -1; // current process
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if (sys_sysctl(cmd, ARRAYLEN(cmd), b, &n, 0, 0) != -1) {
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if (!OldApeLoader(b)) {
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goto UseBuf;
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}
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}
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}
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if (IsLinux()) {
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if ((got = sys_readlinkat(AT_FDCWD, "/proc/self/exe", b, n)) > 0 ||
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(got = sys_readlinkat(AT_FDCWD, "/proc/curproc/file", b, n)) > 0) {
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b[got] = 0;
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if (!OldApeLoader(b)) {
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goto UseBuf;
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}
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}
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}
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// don't trust argument parsing if set-id.
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if (issetugid()) {
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goto UseEmpty;
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}
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// try argv[0], then argv[0].com, then $_, then $_.com.
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if (TryPath(__argv[0], 1) ||
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/* TODO(mrdomino): remove after next loader mint */
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TryPath(__getenv(__envp, "COSMOPOLITAN_PROGRAM_EXECUTABLE").s, 0) ||
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TryPath(__getenv(__envp, "_").s, 1)) {
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goto UseBuf;
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}
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// give up and just copy argv[0] into it
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if ((q = __argv[0])) {
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char *p = g_prog.u.buf;
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char *e = p + sizeof(g_prog.u.buf);
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while ((c = *q++)) {
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if (p + 1 < e) {
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*p++ = c;
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}
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}
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*p = 0;
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goto UseBuf;
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}
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UseEmpty:
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// if we don't even have that then empty the string
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g_prog.u.buf[0] = 0;
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UseBuf:
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__program_executable_name = g_prog.u.buf;
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}
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static void InitProgramExecutableName(void) {
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int e = errno;
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InitProgramExecutableNameImpl();
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errno = e;
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}
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/**
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* Returns absolute path of program.
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*/
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char *GetProgramExecutableName(void) {
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cosmo_once(&g_prog.once, InitProgramExecutableName);
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return __program_executable_name;
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}
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