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TryPath, verify __program_executable_name

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Jōshin 2023-12-17 13:38:24 +00:00
parent b08b92248b
commit 3c7ad0eab2
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1 changed files with 41 additions and 37 deletions
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78
libc/calls/getprogramexecutablename.greg.c
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@ -50,15 +50,46 @@ static inline int IsAlpha(int c) {
return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
}
// if q exists then turn it into an absolute path. we also try adding
// a .com suffix since the ape auto-appends it when resolving
static int TryPath(const char *q, int com) {
if (!q) return 0;
char *p = g_prog.u.buf;
char *e = p + sizeof(g_prog.u.buf);
int c, f_ok;
if ((f_ok = !sys_faccessat(AT_FDCWD, q, F_OK, 0))) {
com = 0;
}
if (*q != '/') {
if (q[0] == '.' && q[1] == '/') {
q += 2;
}
int got = __getcwd(p, e - p - 1 - com * 4); // for / and .com
if (got != -1) {
p += got - 1;
*p++ = '/';
}
}
while ((c = *q++)) {
if (p + 1 + com * 4 < e) { // for nul and .com
*p++ = c;
}
}
if (f_ok) {
*p = 0;
return 1;
}
if (!com) return 0;
p = WRITE32LE(p, READ32LE(".com"));
*p = 0;
return !sys_faccessat(AT_FDCWD, g_prog.u.buf, F_OK, 0);
}
static inline void InitProgramExecutableNameImpl(void) {
size_t n;
ssize_t got;
char c, *q, *b;
if (__program_executable_name) {
/* already set by the loader */
return;
}
if (IsWindows()) {
int n = GetModuleFileName(0, g_prog.u.buf16, ARRAYLEN(g_prog.u.buf16));
for (int i = 0; i < n; ++i) {
@ -116,43 +147,16 @@ static inline void InitProgramExecutableNameImpl(void) {
goto UseEmpty;
}
// if argv[0] exists then turn it into an absolute path. we also try
// adding a .com suffix since the ape auto-appends it when resolving
if ((q = __argv[0])) {
char *p = g_prog.u.buf;
char *e = p + sizeof(g_prog.u.buf);
if (*q != '/') {
if (q[0] == '.' && q[1] == '/') {
q += 2;
}
int got = __getcwd(p, e - p - 1 - 4); // for / and .com
if (got != -1) {
p += got - 1;
*p++ = '/';
}
}
while ((c = *q++)) {
if (p + 1 + 4 < e) { // for nul and .com
*p++ = c;
}
}
*p = 0;
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)) goto UseBuf;
}
/* the previous loader supplied the full program path as the first
environment variable. we also try "_". */
if ((q = __getenv(__envp, "COSMOPOLITAN_PROGRAM_EXECUTABLE").s) ||
(q = __getenv(__envp, "_").s)) {
goto CopyString;
// Try what the loader supplied first. Fall back to argv[0],
// then argv[0].com, then $_, then $_.com.
if (TryPath(__program_executable_name, 0) ||
TryPath(__argv[0], 0) || TryPath(__argv[0], 1) ||
TryPath((q = __getenv(__envp, "_").s), 0) || TryPath(q, 1)) {
goto UseBuf;
}
// give up and just copy argv[0] into it
if ((q = __argv[0])) {
CopyString:
char *p = g_prog.u.buf;
char *e = p + sizeof(g_prog.u.buf);
while ((c = *q++)) {