Move utils_expand_path and utils_expand_path_keep_symlink to libpath.la
[lttng-tools.git] / src / common / utils.c
index 2e07d4ff0b6d366268755b7969dab0d58199385e..4295a584a0b57ed951b80f9007f81c6b19626a75 100644 (file)
@@ -1,22 +1,12 @@
 /*
- * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
- * Copyright (C) 2013 - Raphaël Beamonte <raphael.beamonte@gmail.com>
- * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License, version 2 only, as
- * published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include "common/macros.h"
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <ctype.h>
 #error MAX_NAME_LEN_SCANF_IS_A_BROKEN_API must be updated to match (PROC_MEMINFO_FIELD_MAX_NAME_LEN - 1)
 #endif
 
-/*
- * 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 = NULL, *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) {
-               char *try_path_buf = NULL;
-
-               /*
-                * 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 = lttng_strndup(path, next - path);
-               if (cut_path == NULL) {
-                       PERROR("lttng_strndup");
-                       goto error;
-               }
-
-               try_path_buf = zmalloc(LTTNG_PATH_MAX);
-               if (!try_path_buf) {
-                       PERROR("zmalloc");
-                       goto error;
-               }
-
-               /* Try to resolve this part */
-               try_path = realpath((char *) cut_path, try_path_buf);
-               if (try_path == NULL) {
-                       free(try_path_buf);
-                       /*
-                        * 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 */
-                       try_path_buf = NULL;
-                       free(try_path_prev);
-                       try_path_prev = try_path;
-                       prev = next;
-               }
-
-               /* Free the allocated memory */
-               free(cut_path);
-               cut_path = NULL;
-       }
-
-       /* 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);
-               if (cut_path == NULL) {
-                       PERROR("strdup");
-                       goto error;
-               }
-
-               /* 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);
-               cut_path = NULL;
-               try_path_prev = NULL;
-       /*
-        * 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);
-       free(cut_path);
-       free(try_path);
-       if (try_path_prev != try_path) {
-               free(try_path_prev);
-       }
-       return NULL;
-}
-
-static
-int expand_double_slashes_dot_and_dotdot(char *path)
-{
-       size_t expanded_path_len, path_len;
-       const char *curr_char, *path_last_char, *next_slash, *prev_slash;
-
-       path_len = strlen(path);
-       path_last_char = &path[path_len];
-
-       if (path_len == 0) {
-               goto error;
-       }
-
-       expanded_path_len = 0;
-
-       /* We iterate over the provided path to expand the "//", "../" and "./" */
-       for (curr_char = path; curr_char <= path_last_char; curr_char = next_slash + 1) {
-               /* Find the next forward slash. */
-               size_t curr_token_len;
-
-               if (curr_char == path_last_char) {
-                       expanded_path_len++;
-                       break;
-               }
-
-               next_slash = memchr(curr_char, '/', path_last_char - curr_char);
-               if (next_slash == NULL) {
-                       /* Reached the end of the provided path. */
-                       next_slash = path_last_char;
-               }
-
-               /* Compute how long is the previous token. */
-               curr_token_len = next_slash - curr_char;
-               switch(curr_token_len) {
-               case 0:
-                       /*
-                        * The pointer has not move meaning that curr_char is
-                        * pointing to a slash. It that case there is no token
-                        * to copy, so continue the iteration to find the next
-                        * token
-                        */
-                       continue;
-               case 1:
-                       /*
-                        * The pointer moved 1 character. Check if that
-                        * character is a dot ('.'), if it is: omit it, else
-                        * copy the token to the normalized path.
-                        */
-                       if (curr_char[0] == '.') {
-                               continue;
-                       }
-                       break;
-               case 2:
-                       /*
-                        * The pointer moved 2 characters. Check if these
-                        * characters are double dots ('..'). If that is the
-                        * case, we need to remove the last token of the
-                        * normalized path.
-                        */
-                       if (curr_char[0] == '.' && curr_char[1] == '.') {
-                               /*
-                                * Find the previous path component by
-                                * using the memrchr function to find the
-                                * previous forward slash and substract that
-                                * len to the resulting path.
-                                */
-                               prev_slash = lttng_memrchr(path, '/', expanded_path_len);
-                               /*
-                                * If prev_slash is NULL, we reached the
-                                * beginning of the path. We can't go back any
-                                * further.
-                                */
-                               if (prev_slash != NULL) {
-                                       expanded_path_len = prev_slash - path;
-                               }
-                               continue;
-                       }
-                       break;
-               default:
-                       break;
-               }
-
-               /*
-                * Copy the current token which is neither a '.' nor a '..'.
-                */
-               path[expanded_path_len++] = '/';
-               memcpy(&path[expanded_path_len], curr_char, curr_token_len);
-               expanded_path_len += curr_token_len;
-       }
-
-       if (expanded_path_len == 0) {
-               path[expanded_path_len++] = '/';
-       }
-
-       path[expanded_path_len] = '\0';
-       return 0;
-error:
-       return -1;
-}
-
-/*
- * Make a full resolution of the given path even if it doesn't exist.
- * This function uses the utils_partial_realpath function to resolve
- * symlinks and relatives paths at the start of the string, and
- * implements functionnalities to resolve the './' and '../' strings
- * in the middle of a path. This function is only necessary because
- * realpath(3) does not accept to resolve unexistent paths.
- * The returned string was allocated in the function, it is thus of
- * the responsibility of the caller to free this memory.
- */
-static
-char *_utils_expand_path(const char *path, bool keep_symlink)
-{
-       int ret;
-       char *absolute_path = NULL;
-       char *last_token;
-       bool is_dot, is_dotdot;
-
-       /* Safety net */
-       if (path == NULL) {
-               goto error;
-       }
-
-       /* Allocate memory for the absolute_path */
-       absolute_path = zmalloc(LTTNG_PATH_MAX);
-       if (absolute_path == NULL) {
-               PERROR("zmalloc expand path");
-               goto error;
-       }
-
-       if (path[0] == '/') {
-               ret = lttng_strncpy(absolute_path, path, LTTNG_PATH_MAX);
-               if (ret) {
-                       ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX);
-                       goto error;
-               }
-       } else {
-               /*
-                * This is a relative path. We need to get the present working
-                * directory and start the path walk from there.
-                */
-               char current_working_dir[LTTNG_PATH_MAX];
-               char *cwd_ret;
-
-               cwd_ret = getcwd(current_working_dir, sizeof(current_working_dir));
-               if (!cwd_ret) {
-                       goto error;
-               }
-               /*
-                * Get the number of character in the CWD and allocate an array
-                * to can hold it and the path provided by the caller.
-                */
-               ret = snprintf(absolute_path, LTTNG_PATH_MAX, "%s/%s",
-                               current_working_dir, path);
-               if (ret >= LTTNG_PATH_MAX) {
-                       ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes",
-                                       current_working_dir, path, LTTNG_PATH_MAX);
-                       goto error;
-               }
-       }
-
-       if (keep_symlink) {
-               /* Resolve partially our path */
-               absolute_path = utils_partial_realpath(absolute_path,
-                               absolute_path, LTTNG_PATH_MAX);
-               if (!absolute_path) {
-                       goto error;
-               }
-       }
-
-       ret = expand_double_slashes_dot_and_dotdot(absolute_path);
-       if (ret) {
-               goto error;
-       }
-
-       /* Identify the last token */
-       last_token = strrchr(absolute_path, '/');
-
-       /* Verify that this token is not a relative path */
-       is_dotdot = (strcmp(last_token, "/..") == 0);
-       is_dot = (strcmp(last_token, "/.") == 0);
-
-       /* If it is, take action */
-       if (is_dot || is_dotdot) {
-               /* For both, remove this token */
-               *last_token = '\0';
-
-               /* If it was a reference to parent directory, go back one more time */
-               if (is_dotdot) {
-                       last_token = strrchr(absolute_path, '/');
-
-                       /* If there was only one level left, we keep the first '/' */
-                       if (last_token == absolute_path) {
-                               last_token++;
-                       }
-
-                       *last_token = '\0';
-               }
-       }
+#define FALLBACK_USER_BUFLEN 16384
+#define FALLBACK_GROUP_BUFLEN 16384
 
-       return absolute_path;
-
-error:
-       free(absolute_path);
-       return NULL;
-}
-LTTNG_HIDDEN
-char *utils_expand_path(const char *path)
-{
-       return _utils_expand_path(path, true);
-}
-
-LTTNG_HIDDEN
-char *utils_expand_path_keep_symlink(const char *path)
-{
-       return _utils_expand_path(path, false);
-}
 /*
  * Create a pipe in dst.
  */
@@ -547,6 +169,7 @@ void utils_close_pipe(int *src)
                if (ret) {
                        PERROR("close pipe");
                }
+               src[i] = -1;
        }
 }
 
@@ -682,21 +305,22 @@ LTTNG_HIDDEN
 int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
 {
        int ret;
-       struct lttng_directory_handle handle;
+       struct lttng_directory_handle *handle;
        const struct lttng_credentials creds = {
                .uid = (uid_t) uid,
                .gid = (gid_t) gid,
        };
 
-       ret = lttng_directory_handle_init(&handle, NULL);
-       if (ret) {
+       handle = lttng_directory_handle_create(NULL);
+       if (!handle) {
+               ret = -1;
                goto end;
        }
        ret = lttng_directory_handle_create_subdirectory_as_user(
-                       &handle, path, mode,
+                       handle, path, mode,
                        (uid >= 0 || gid >= 0) ? &creds : NULL);
-       lttng_directory_handle_fini(&handle);
 end:
+       lttng_directory_handle_put(handle);
        return ret;
 }
 
@@ -710,21 +334,22 @@ LTTNG_HIDDEN
 int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
 {
        int ret;
-       struct lttng_directory_handle handle;
+       struct lttng_directory_handle *handle;
        const struct lttng_credentials creds = {
                .uid = (uid_t) uid,
                .gid = (gid_t) gid,
        };
 
-       ret = lttng_directory_handle_init(&handle, NULL);
-       if (ret) {
+       handle = lttng_directory_handle_create(NULL);
+       if (!handle) {
+               ret = -1;
                goto end;
        }
        ret = lttng_directory_handle_create_subdirectory_recursive_as_user(
-                       &handle, path, mode,
+                       handle, path, mode,
                        (uid >= 0 || gid >= 0) ? &creds : NULL);
-       lttng_directory_handle_fini(&handle);
 end:
+       lttng_directory_handle_put(handle);
        return ret;
 }
 
@@ -742,7 +367,8 @@ int utils_stream_file_path(const char *path_name, const char *file_name,
         char count_str[MAX_INT_DEC_LEN(count) + 1] = {};
        const char *path_separator;
 
-       if (path_name && path_name[strlen(path_name) - 1] == '/') {
+       if (path_name && (path_name[0] == '\0' ||
+                       path_name[strlen(path_name) - 1] == '/')) {
                path_separator = "";
        } else {
                path_separator = "/";
@@ -1276,8 +902,14 @@ int utils_get_group_id(const char *name, bool warn, gid_t *gid)
                }
        }
        if (ret) {
-               PERROR("Failed to get group file entry for group name \"%s\"",
-                               name);
+               if (ret == ESRCH) {
+                       DBG("Could not find group file entry for group name '%s'",
+                                       name);
+               } else {
+                       PERROR("Failed to get group file entry for group name '%s'",
+                                       name);
+               }
+
                ret = -1;
                goto error;
        }
@@ -1353,15 +985,16 @@ LTTNG_HIDDEN
 int utils_recursive_rmdir(const char *path)
 {
        int ret;
-       struct lttng_directory_handle handle;
+       struct lttng_directory_handle *handle;
 
-       ret = lttng_directory_handle_init(&handle, NULL);
-       if (ret) {
+       handle = lttng_directory_handle_create(NULL);
+       if (!handle) {
+               ret = -1;
                goto end;
        }
-       ret = lttng_directory_handle_remove_subdirectory(&handle, path);
-       lttng_directory_handle_fini(&handle);
+       ret = lttng_directory_handle_remove_subdirectory(handle, path);
 end:
+       lttng_directory_handle_put(handle);
        return ret;
 }
 
@@ -1533,3 +1166,134 @@ int utils_change_working_directory(const char *path)
 end:
        return ret;
 }
+
+LTTNG_HIDDEN
+enum lttng_error_code utils_user_id_from_name(const char *user_name, uid_t *uid)
+{
+       struct passwd p, *pres;
+       int ret;
+       enum lttng_error_code ret_val = LTTNG_OK;
+       char *buf = NULL;
+       ssize_t buflen;
+
+       buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+       if (buflen < 0) {
+               buflen = FALLBACK_USER_BUFLEN;
+       }
+
+       buf = zmalloc(buflen);
+       if (!buf) {
+               ret_val = LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       for (;;) {
+               ret = getpwnam_r(user_name, &p, buf, buflen, &pres);
+               switch (ret) {
+               case EINTR:
+                       continue;
+               case ERANGE:
+                       buflen *= 2;
+                       free(buf);
+                       buf = zmalloc(buflen);
+                       if (!buf) {
+                               ret_val = LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+                       continue;
+               default:
+                       goto end_loop;
+               }
+       }
+end_loop:
+
+       switch (ret) {
+       case 0:
+               if (pres == NULL) {
+                       ret_val = LTTNG_ERR_USER_NOT_FOUND;
+               } else {
+                       *uid = p.pw_uid;
+                       DBG("Lookup of tracker UID/VUID: name '%s' maps to uid %" PRId64,
+                                       user_name, (int64_t) *uid);
+                       ret_val = LTTNG_OK;
+               }
+               break;
+       case ENOENT:
+       case ESRCH:
+       case EBADF:
+       case EPERM:
+               ret_val = LTTNG_ERR_USER_NOT_FOUND;
+               break;
+       default:
+               ret_val = LTTNG_ERR_NOMEM;
+       }
+end:
+       free(buf);
+       return ret_val;
+}
+
+LTTNG_HIDDEN
+enum lttng_error_code utils_group_id_from_name(
+               const char *group_name, gid_t *gid)
+{
+       struct group g, *gres;
+       int ret;
+       enum lttng_error_code ret_val = LTTNG_OK;
+       char *buf = NULL;
+       ssize_t buflen;
+
+       buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+       if (buflen < 0) {
+               buflen = FALLBACK_GROUP_BUFLEN;
+       }
+
+       buf = zmalloc(buflen);
+       if (!buf) {
+               ret_val = LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       for (;;) {
+               ret = getgrnam_r(group_name, &g, buf, buflen, &gres);
+               switch (ret) {
+               case EINTR:
+                       continue;
+               case ERANGE:
+                       buflen *= 2;
+                       free(buf);
+                       buf = zmalloc(buflen);
+                       if (!buf) {
+                               ret_val = LTTNG_ERR_NOMEM;
+                               goto end;
+                       }
+                       continue;
+               default:
+                       goto end_loop;
+               }
+       }
+end_loop:
+
+       switch (ret) {
+       case 0:
+               if (gres == NULL) {
+                       ret_val = LTTNG_ERR_GROUP_NOT_FOUND;
+               } else {
+                       *gid = g.gr_gid;
+                       DBG("Lookup of tracker GID/GUID: name '%s' maps to gid %" PRId64,
+                                       group_name, (int64_t) *gid);
+                       ret_val = LTTNG_OK;
+               }
+               break;
+       case ENOENT:
+       case ESRCH:
+       case EBADF:
+       case EPERM:
+               ret_val = LTTNG_ERR_GROUP_NOT_FOUND;
+               break;
+       default:
+               ret_val = LTTNG_ERR_NOMEM;
+       }
+end:
+       free(buf);
+       return ret_val;
+}
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