#include "utils.h"
#include "defaults.h"
+/*
+ * Return a partial realpath(3) of the path even if the full path does not
+ * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
+ * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
+ * /test2/test3 then returned. In normal time, realpath(3) fails if the end
+ * point directory does not exist.
+ * In case resolved_path is NULL, the string returned was allocated in the
+ * function and thus need to be freed by the caller. The size argument allows
+ * to specify the size of the resolved_path argument if given, or the size to
+ * allocate.
+ */
+LTTNG_HIDDEN
+char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
+{
+ char *cut_path, *try_path = NULL, *try_path_prev = NULL;
+ const char *next, *prev, *end;
+
+ /* Safety net */
+ if (path == NULL) {
+ goto error;
+ }
+
+ /*
+ * Identify the end of the path, we don't want to treat the
+ * last char if it is a '/', we will just keep it on the side
+ * to be added at the end, and return a value coherent with
+ * the path given as argument
+ */
+ end = path + strlen(path);
+ if (*(end-1) == '/') {
+ end--;
+ }
+
+ /* Initiate the values of the pointers before looping */
+ next = path;
+ prev = next;
+ /* Only to ensure try_path is not NULL to enter the while */
+ try_path = (char *)next;
+
+ /* Resolve the canonical path of the first part of the path */
+ while (try_path != NULL && next != end) {
+ /*
+ * If there is not any '/' left, we want to try with
+ * the full path
+ */
+ next = strpbrk(next + 1, "/");
+ if (next == NULL) {
+ next = end;
+ }
+
+ /* Cut the part we will be trying to resolve */
+ cut_path = strndup(path, next - path);
+
+ /* Try to resolve this part */
+ try_path = realpath((char *)cut_path, NULL);
+ if (try_path == NULL) {
+ /*
+ * There was an error, we just want to be assured it
+ * is linked to an unexistent directory, if it's another
+ * reason, we spawn an error
+ */
+ switch (errno) {
+ case ENOENT:
+ /* Ignore the error */
+ break;
+ default:
+ PERROR("realpath (partial_realpath)");
+ goto error;
+ break;
+ }
+ } else {
+ /* Save the place we are before trying the next step */
+ free(try_path_prev);
+ try_path_prev = try_path;
+ prev = next;
+ }
+
+ /* Free the allocated memory */
+ free(cut_path);
+ };
+
+ /* Allocate memory for the resolved path if necessary */
+ if (resolved_path == NULL) {
+ resolved_path = zmalloc(size);
+ if (resolved_path == NULL) {
+ PERROR("zmalloc resolved path");
+ goto error;
+ }
+ }
+
+ /*
+ * If we were able to solve at least partially the path, we can concatenate
+ * what worked and what didn't work
+ */
+ if (try_path_prev != NULL) {
+ /* If we risk to concatenate two '/', we remove one of them */
+ if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') {
+ try_path_prev[strlen(try_path_prev) - 1] = '\0';
+ }
+
+ /*
+ * Duplicate the memory used by prev in case resolved_path and
+ * path are pointers for the same memory space
+ */
+ cut_path = strdup(prev);
+
+ /* Concatenate the strings */
+ snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
+
+ /* Free the allocated memory */
+ free(cut_path);
+ free(try_path_prev);
+ /*
+ * Else, we just copy the path in our resolved_path to
+ * return it as is
+ */
+ } else {
+ strncpy(resolved_path, path, size);
+ }
+
+ /* Then we return the 'partially' resolved path */
+ return resolved_path;
+
+error:
+ free(resolved_path);
+ return NULL;
+}
+
/*
* Resolve the './' and '../' strings in the middle of a path using
* our very own way to do it, so that it works even if the directory
LTTNG_HIDDEN
char *utils_expand_path(const char *path)
{
- const char *end_path = path;
+ const char *end_path = NULL;
char *next, *cut_path = NULL, *expanded_path = NULL;
/* Safety net */
goto error;
}
- /* Find last token delimited by '/' */
- while ((next = strpbrk(end_path + 1, "/"))) {
- end_path = next;
- }
-
- /* Cut last token from original path */
- cut_path = strndup(path, end_path - path);
-
+ /* Allocate memory for the expanded path */
expanded_path = zmalloc(PATH_MAX);
if (expanded_path == NULL) {
PERROR("zmalloc expand path");
goto error;
}
- expanded_path = realpath((char *)cut_path, expanded_path);
- if (expanded_path == NULL) {
- switch (errno) {
- case ENOENT:
- ERR("%s: No such file or directory", cut_path);
- break;
- default:
- PERROR("realpath utils expand path");
- break;
+ /* If given path is already absolute */
+ if (*path == '/') {
+ strncpy(expanded_path, path, PATH_MAX);
+ /* Else, we have some work to do */
+ } else {
+ /* Pointer to the last char of the path */
+ const char *last_char = path + strlen(path) - 1;
+
+ end_path = path;
+
+ /* Split part that will be resolved by realpath (relative path from
+ * current directory using ./ or ../ only) and part that could not
+ * (directory names)
+ */
+ while ((next = strpbrk(end_path, "/")) && (next != last_char)) {
+ end_path = next + 1;
+ if (strncmp(end_path, "./", 2) != 0 &&
+ strncmp(end_path, "../", 3) != 0) {
+ break;
+ }
+ }
+
+ /* If this is the end of the string, and we still can resolve it */
+ if (strncmp(end_path, "..\0", 3) == 0 ||
+ strncmp(end_path, ".\0", 2) == 0) {
+ end_path += strlen(end_path);
+ }
+
+ /* If the end part is the whole path, we are in the current dir */
+ if (end_path == path) {
+ cut_path = strdup(".");
+ /* Else, cut the resolvable part from original path */
+ } else {
+ cut_path = strndup(path, end_path - path);
+ }
+
+ /* Resolve the canonical path of the first part of the path */
+ expanded_path = realpath((char *)cut_path, expanded_path);
+ if (expanded_path == NULL) {
+ switch (errno) {
+ case ENOENT:
+ ERR("%s: No such file or directory", cut_path);
+ break;
+ default:
+ PERROR("realpath utils expand path");
+ break;
+ }
+ goto error;
+ }
+
+ /* Add end part to expanded path if not empty */
+ if (*end_path != 0) {
+ strncat(expanded_path, "/", PATH_MAX - strlen(expanded_path) - 1);
+ strncat(expanded_path, end_path,
+ PATH_MAX - strlen(expanded_path) - 1);
}
- goto error;
}
- /* Add end part to expanded path */
- strncat(expanded_path, end_path, PATH_MAX - strlen(expanded_path) - 1);
+ /* Resolve the internal './' and '../' strings */
+ next = utils_resolve_relative(expanded_path);
+ if (next == NULL) {
+ goto error;
+ }
+ free(expanded_path);
free(cut_path);
- return expanded_path;
+ return next;
error:
free(expanded_path);