// Documented in header.
char *utf8DupFromZstring(zstring string) {
zint size = utf8SizeFromZstring(string) + 1; // `+1` for the final `\0`.
char *result = utilAlloc(size);
utf8FromZstring(size, result, string);
return result;
}
// Documented in header.
char *utilReadLink(const char *path) {
struct stat statBuf;
if (lstat(path, &statBuf) != 0) {
if ((errno == ENOENT) || (errno == ENOTDIR)) {
// File not found or invalid component, neither of which are
// really errors from the perspective of this function.
errno = 0;
return NULL;
}
die("Trouble with `lstat`: %s", strerror(errno));
} else if (!S_ISLNK(statBuf.st_mode)) {
// Not a symlink.
errno = 0;
return NULL;
}
// If `st_size` is non-zero, then it can safely be used as the size of
// the link data. However, on Linux some valid links (particularly, those
// in `/proc/`) will have `st_size` reported as `0`. In such cases, we
// use an ample but fixed-size buffer, and hope for the best.
bool assumeSize = (statBuf.st_size == 0);
size_t linkSz = assumeSize ? 500 : statBuf.st_size;
char *result = utilAlloc(linkSz + 1);
ssize_t resultSz = readlink(path, result, linkSz);
if (resultSz < 0) {
die("Trouble with `readlink`: %s", strerror(errno));
} else if (assumeSize ? (resultSz > linkSz) : (resultSz != linkSz)) {
die("Strange `readlink` result: %d", (zint) resultSz);
}
result[resultSz] = '\0';
return result;
}