+/* Licensed under BSD-MIT - see LICENSE file for details */
+#include <ccan/tal/path/path.h>
+#include <ccan/str/str.h>
+#include <ccan/take/take.h>
+#include <ccan/tal/str/str.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <assert.h>
+
+#define PATH_SEP_STR "/"
+#define PATH_SEP (PATH_SEP_STR[0])
+
+char *path_cwd(const tal_t *ctx)
+{
+ size_t len = 64;
+ char *cwd;
+
+ /* *This* is why people hate C. */
+ cwd = tal_arr(ctx, char, len);
+ while (cwd && !getcwd(cwd, len)) {
+ if (errno != ERANGE || !tal_resize(&cwd, len *= 2))
+ cwd = tal_free(cwd);
+ }
+ return cwd;
+}
+
+char *path_join(const tal_t *ctx, const char *base, const char *a)
+{
+ char *ret = NULL;
+ size_t len;
+
+ if (unlikely(!a) && taken(a)) {
+ if (taken(base))
+ tal_free(base);
+ return NULL;
+ }
+
+ if (a[0] == PATH_SEP) {
+ if (taken(base))
+ tal_free(base);
+ return tal_strdup(ctx, a);
+ }
+
+ if (unlikely(!base) && taken(base))
+ goto out;
+
+ len = strlen(base);
+ ret = tal_dup(ctx, char, base, len, 1 + strlen(a) + 1);
+ if (!ret)
+ goto out;
+ if (ret[len-1] != PATH_SEP)
+ ret[len++] = PATH_SEP;
+ strcpy(ret + len, a);
+
+out:
+ if (taken(a))
+ tal_free(a);
+ return ret;
+}
+
+#if HAVE_FCHDIR
+struct path_pushd {
+ int fd;
+};
+
+static void pushd_destroy(struct path_pushd *pushd)
+{
+ close(pushd->fd);
+}
+
+struct path_pushd *path_pushd(const tal_t *ctx, const char *dir)
+{
+ struct path_pushd *old = tal(ctx, struct path_pushd);
+
+ if (!old)
+ return NULL;
+
+ if (unlikely(!dir) && taken(dir))
+ return tal_free(old);
+
+ if (!tal_add_destructor(old, pushd_destroy))
+ old = tal_free(old);
+ else {
+ old->fd = open(".", O_RDONLY);
+ if (old->fd < 0)
+ old = tal_free(old);
+ else if (chdir(dir) != 0)
+ old = tal_free(old);
+ }
+
+ if (taken(dir))
+ tal_free(dir);
+ return old;
+}
+
+bool path_popd(struct path_pushd *olddir)
+{
+ bool ok = (fchdir(olddir->fd) == 0);
+
+ tal_free(olddir);
+ return ok;
+}
+#else
+struct path_pushd {
+ const char *olddir;
+};
+
+struct path_pushd *path_pushd(const tal_t *ctx, const char *dir)
+{
+ struct path_pushd *old = tal(ctx, struct path_pushd);
+
+ if (!old)
+ return NULL;
+
+ old->olddir = path_cwd(old);
+ if (unlikely(!old->olddir))
+ old = tal_free(old);
+ else if (unlikely(!dir) && is_taken(dir))
+ old = tal_free(old);
+ else if (chdir(dir) != 0)
+ old = tal_free(old);
+
+ if (taken(dir))
+ tal_free(dir);
+
+ return old;
+}
+
+bool path_popd(struct path_pushd *olddir)
+{
+ bool ok = (chdir(olddir->olddir) == 0);
+
+ tal_free(olddir);
+ return ok;
+}
+#endif /* !HAVE_FCHDIR */
+
+char *path_canon(const tal_t *ctx, const char *a)
+{
+#if 0
+ char *oldcwd, *path, *p;
+ void *tmpctx;
+ size_t len;
+ struct path_pushd *olddir;
+
+ /* A good guess as to size. */
+ len = strlen(a) + 1;
+ if (a[0] != PATH_SEP) {
+ tmpctx = oldcwd = path_cwd(ctx);
+ if (!oldcwd)
+ return NULL;
+ len += strlen(oldcwd) + strlen(PATH_SEP_STR);
+
+ path = tal_array(tmpctx, char, len);
+ if (!path)
+ goto out;
+
+ len = strlen(oldcwd);
+ memcpy(path, oldcwd, len);
+ path[len++] = PATH_SEP;
+ } else {
+ tmpctx = path = tal_array(ctx, char, len);
+ if (!path)
+ return NULL;
+ len = 0;
+ }
+ strcpy(path + len, a);
+
+ p = strrchr(path, PATH_SEP);
+ *p = '\0';
+
+ olddir = path_pushd(tmpctx, path);
+ if (!olddir)
+ goto out;
+
+ /* Make OS canonicalize path for us. */
+ path = path_cwd(tmpctx);
+ if (!path)
+ goto out;
+
+ /* Append rest of old path. */
+ len = strlen(p+1);
+ if (len) {
+ size_t oldlen = tal_array_length(path);
+ if (path[oldlen-1] != PATH_SEP) {
+ /* Include / to append. */
+ *p = PATH_SEP;
+ p--;
+ len++;
+ }
+ path = tal_realloc(NULL, path, char, oldlen+len+1);
+ if (!path)
+ goto out;
+ memcpy(path + oldlen, p, len+1);
+ }
+
+ path = tal_steal(ctx, path);
+out:
+ /* This can happen if old cwd is deleted. */
+ if (!path_popd(olddir))
+ path = tal_free(path);
+
+ tal_free(tmpctx);
+ return path;
+#else
+ char *path;
+ if (unlikely(!a) && is_taken(a))
+ path = NULL;
+ else {
+ path = tal_arr(ctx, char, PATH_MAX);
+ if (path && !realpath(a, path))
+ path = tal_free(path);
+ }
+ if (taken(a))
+ tal_free(a);
+ return path;
+#endif
+}
+
+/* Symlinks make this hard! */
+char *path_rel(const tal_t *ctx, const char *from, const char *to)
+{
+ char *cfrom, *cto, *ret, *p;
+ tal_t *tmpctx;
+ size_t common, num_back, i, postlen;
+
+ /* This frees from if we're supposed to take it. */
+ tmpctx = cfrom = path_canon(ctx, from);
+ if (!cfrom)
+ goto fail_take_to;
+
+ /* From is a directory, so we append / to it. */
+ if (!streq(cfrom, PATH_SEP_STR)) {
+ if (!tal_resize(&cfrom, strlen(cfrom)+2))
+ goto fail_take_to;
+ tmpctx = cfrom;
+ strcat(cfrom, PATH_SEP_STR);
+ }
+
+ /* This frees to if we're supposed to take it. */
+ cto = path_canon(tmpctx, to);
+ if (!cto)
+ goto out;
+
+ /* How much is in common? */
+ for (common = i = 0; cfrom[i] && cto[i]; i++) {
+ if (cfrom[i] != cto[i])
+ break;
+ if (cfrom[i] == PATH_SEP)
+ common = i + 1;
+ }
+
+ /* Skip over / if matches end of other path. */
+ if (!cfrom[i] && cto[i] == PATH_SEP) {
+ cto++;
+ common = i;
+ } else if (!cto[i] && cfrom[i] == PATH_SEP) {
+ cfrom++;
+ common = i;
+ }
+
+ /* Normalize so strings point past common area. */
+ cfrom += common;
+ cto += common;
+
+ /* One .. for every path element remaining in 'from', to get
+ * back to common prefix. Then the rest of 'to'. */
+ num_back = strcount(cfrom, PATH_SEP_STR);
+ postlen = strlen(cto) + 1;
+
+ /* Nothing left? That's ".". */
+ if (num_back == 0 && postlen == 1) {
+ ret = tal_strdup(ctx, ".");
+ goto out;
+ }
+
+ ret = tal_arr(ctx, char,
+ strlen(".." PATH_SEP_STR) * num_back + postlen);
+ if (!ret)
+ goto out;
+
+ for (i = 0, p = ret; i < num_back; i++, p += strlen(".." PATH_SEP_STR))
+ memcpy(p, ".." PATH_SEP_STR, strlen(".." PATH_SEP_STR));
+ /* Nothing to append? Trim the final / */
+ if (postlen == 1)
+ p--;
+ memcpy(p, cto, postlen);
+
+out:
+ tal_free(tmpctx);
+ return ret;
+
+fail_take_to:
+ if (taken(to))
+ tal_free(to);
+ ret = NULL;
+ goto out;
+}
+
+ char *path_readlink(const tal_t *ctx, const char *linkname)
+ {
+ ssize_t len, maxlen = 64; /* good first guess. */
+ char *ret = NULL;
+
+ if (unlikely(!linkname) && is_taken(linkname))
+ goto fail;
+
+ ret = tal_arr(ctx, char, maxlen + 1);
+
+ while (ret) {
+ len = readlink(linkname, ret, maxlen);
+ if (len < 0)
+ goto fail;
+ if (len < maxlen)
+ break;
+
+ if (!tal_resize(&ret, maxlen *= 2 + 1))
+ goto fail;
+ }
+
+ ret[len] = '\0';
+out:
+ if (taken(linkname))
+ tal_free(linkname);
+
+ return ret;
+
+fail:
+ ret = tal_free(ret);
+ goto out;
+}
+
+char *path_simplify(const tal_t *ctx, const char *path)
+{
+ size_t i, j, start, len;
+ char *ret;
+ bool ended = false;
+
+ ret = tal_strdup(ctx, path);
+ if (!ret)
+ return NULL;
+
+ /* Always need first / if there is one. */
+ if (ret[0] == PATH_SEP)
+ start = 1;
+ else
+ start = 0;
+
+ for (i = j = start; !ended; i += len) {
+ /* Get length of this segment, including terminator. */
+ for (len = 0; ret[i+len] != PATH_SEP; len++) {
+ if (!ret[i+len]) {
+ ended = true;
+ break;
+ }
+ }
+ len++;
+
+ /* Empty segment is //; ignore first one. */
+ if (len == 1)
+ continue;
+
+ /* Always ignore slashdot. */
+ if (len == 2 && ret[i] == '.')
+ continue;
+
+ /* .. => remove previous if there is one, unless symlink. */
+ if (len == 3 && ret[i] == '.' && ret[i+1] == '.') {
+ struct stat st;
+
+ if (j > start) {
+ /* eg. /foo/, foo/ or foo/bar/ */
+ assert(ret[j-1] == PATH_SEP);
+ ret[j-1] = '\0';
+
+ /* Avoid stepping back over ..! */
+ if (streq(ret, "..")
+ || strends(ret, PATH_SEP_STR"..")) {
+ ret[j-1] = PATH_SEP;
+ goto copy;
+ }
+
+ if (lstat(ret, &st) == 0
+ && !S_ISLNK(st.st_mode)) {
+ char *sep = strrchr(ret, PATH_SEP);
+ if (sep)
+ j = sep - ret + 1;
+ else
+ j = 0;
+ }
+ continue;
+ } else if (start) {
+ /* /.. => / */
+ j = 1;
+ /* nul term in case we're at end */
+ ret[1] = '\0';
+ continue;
+ }
+ }
+
+ copy:
+ memmove(ret + j, ret + i, len);
+ /* Don't count nul terminator. */
+ j += len - ended;
+ }
+
+ /* Empty string created by ../ elimination. */
+ if (j == 0) {
+ ret[0] = '.';
+ ret[1] = '\0';
+ } else if (j > 1 && ret[j-1] == PATH_SEP) {
+ ret[j-1] = '\0';
+ } else
+ ret[j] = '\0';
+
+ return ret;
+}
+
+char *path_basename(const tal_t *ctx, const char *path)
+{
+ const char *sep;
+ char *ret;
+
+ if (unlikely(!path) && taken(path))
+ return NULL;
+
+ sep = strrchr(path, PATH_SEP);
+ if (!sep)
+ return tal_strdup(ctx, path);
+
+ /* Trailing slashes need to be trimmed. */
+ if (!sep[1]) {
+ const char *end;
+
+ for (end = sep; end != path; end--)
+ if (*end != PATH_SEP)
+ break;
+
+ /* Find *previous* / */
+ for (sep = end; sep >= path && *sep != PATH_SEP; sep--);
+
+ /* All /? Just return / */
+ if (end == sep)
+ ret = tal_strdup(ctx, PATH_SEP_STR);
+ else
+ ret = tal_strndup(ctx, sep+1, end - sep);
+ } else
+ ret = tal_strdup(ctx, sep + 1);
+
+ if (taken(path))
+ tal_free(path);
+ return ret;
+}
+
+/* This reuses str if we're to take it. */
+static char *fixed_string(const tal_t *ctx,
+ const char *str, const char *path)
+{
+ char *ret = tal_dup(ctx, char, path, 0, strlen(str)+1);
+ if (ret)
+ strcpy(ret, str);
+ return ret;
+}
+
+char *path_dirname(const tal_t *ctx, const char *path)
+{
+ const char *sep;
+
+ if (unlikely(!path) && taken(path))
+ return NULL;
+
+ sep = strrchr(path, PATH_SEP);
+ if (!sep)
+ return fixed_string(ctx, ".", path);
+
+ /* Trailing slashes need to be trimmed. */
+ if (!sep[1]) {
+ const char *end;
+
+ for (end = sep; end != path; end--)
+ if (*end != PATH_SEP)
+ break;
+
+ /* Find *previous* / */
+ for (sep = end; sep > path && *sep != PATH_SEP; sep--);
+ }
+
+ /* In case there are multiple / in a row. */
+ while (sep > path && sep[-1] == PATH_SEP)
+ sep--;
+
+ if (sep == path) {
+ if (path_is_abs(path))
+ return tal_strndup(ctx, path, 1);
+ else
+ return fixed_string(ctx, ".", path);
+ }
+ return tal_strndup(ctx, path, sep - path);
+}
+
+bool path_is_abs(const char *path)
+{
+ return path[0] == PATH_SEP;
+}
+
+bool path_is_file(const char *path)
+{
+ struct stat st;
+
+ return stat(path, &st) == 0 && S_ISREG(st.st_mode);
+}
+
+bool path_is_dir(const char *path)
+{
+ struct stat st;
+
+ return stat(path, &st) == 0 && S_ISDIR(st.st_mode);
+}
+
+char **path_split(const tal_t *ctx, const char *path)
+{
+ bool empty = path && !path[0];
+ char **ret = strsplit(ctx, path, PATH_SEP_STR, STR_NO_EMPTY);
+
+ /* Handle the "/" case */
+ if (ret && !empty && !ret[0]) {
+ if (!tal_resize(&ret, 2))
+ ret = tal_free(ret);
+ else {
+ ret[1] = NULL;
+ ret[0] = tal_strdup(ret, PATH_SEP_STR);
+ if (!ret[0])
+ ret = tal_free(ret);
+ }
+ }
+
+ return ret;
+}
+
+size_t path_ext_off(const char *path)
+{
+ const char *dot, *base;
+
+ dot = strrchr(path, '.');
+ if (dot) {
+ base = strrchr(path, PATH_SEP);
+ if (!base)
+ base = path;
+ else
+ base++;
+ if (dot > base)
+ return dot - path;
+ }
+ return strlen(path);
+}
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