Merge pull request #96 from gentoo/refactor-shared

src/shared: refactor shared code

1 files changed, 364 insertions, 0 deletions

diff --git a/src/shared/path-util.c b/src/shared/path-util.c
new file mode 100644
index 0000000000..41bc20de69
--- /dev/null
+++ b/src/shared/path-util.c
@@ -0,0 +1,364 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010-2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <assert.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/statvfs.h>
+
+#include "macro.h"
+#include "util.h"
+#include "log.h"
+#include "strv.h"
+#include "path-util.h"
+#include "missing.h"
+
+bool path_is_absolute(const char *p) {
+        return p[0] == '/';
+}
+
+char *path_get_file_name(const char *p) {
+        char *r;
+
+        assert(p);
+
+        r = strrchr(p, '/');
+        if (r)
+                return r + 1;
+
+        return (char*) p;
+}
+
+int path_get_parent(const char *path, char **_r) {
+        const char *e, *a = NULL, *b = NULL, *p;
+        char *r;
+        bool slash = false;
+
+        assert(path);
+        assert(_r);
+
+        if (!*path)
+                return -EINVAL;
+
+        for (e = path; *e; e++) {
+
+                if (!slash && *e == '/') {
+                        a = b;
+                        b = e;
+                        slash = true;
+                } else if (slash && *e != '/')
+                        slash = false;
+        }
+
+        if (*(e-1) == '/')
+                p = a;
+        else
+                p = b;
+
+        if (!p)
+                return -EINVAL;
+
+        if (p == path)
+                r = strdup("/");
+        else
+                r = strndup(path, p-path);
+
+        if (!r)
+                return -ENOMEM;
+
+        *_r = r;
+        return 0;
+}
+
+char *path_make_absolute(const char *p, const char *prefix) {
+        assert(p);
+
+        /* Makes every item in the list an absolute path by prepending
+         * the prefix, if specified and necessary */
+
+        if (path_is_absolute(p) || !prefix)
+                return strdup(p);
+
+        return strjoin(prefix, "/", p, NULL);
+}
+
+char *path_make_absolute_cwd(const char *p) {
+        _cleanup_free_ char *cwd = NULL;
+
+        assert(p);
+
+        /* Similar to path_make_absolute(), but prefixes with the
+         * current working directory. */
+
+        if (path_is_absolute(p))
+                return strdup(p);
+
+        cwd = get_current_dir_name();
+        if (!cwd)
+                return NULL;
+
+        return path_make_absolute(p, cwd);
+}
+
+char **path_strv_canonicalize(char **l) {
+        char **s;
+        unsigned k = 0;
+        bool enomem = false;
+
+        if (strv_isempty(l))
+                return l;
+
+        /* Goes through every item in the string list and canonicalize
+         * the path. This works in place and won't rollback any
+         * changes on failure. */
+
+        STRV_FOREACH(s, l) {
+                char *t, *u;
+
+                t = path_make_absolute_cwd(*s);
+                free(*s);
+                *s = NULL;
+
+                if (!t) {
+                        enomem = true;
+                        continue;
+                }
+
+                errno = 0;
+                u = realpath(t, 0);
+                if (!u) {
+                        if (errno == ENOENT)
+                                u = t;
+                        else {
+                                free(t);
+                                if (errno == ENOMEM || !errno)
+                                        enomem = true;
+
+                                continue;
+                        }
+                } else
+                        free(t);
+
+                l[k++] = u;
+        }
+
+        l[k] = NULL;
+
+        if (enomem)
+                return NULL;
+
+        return l;
+}
+
+char **path_strv_canonicalize_uniq(char **l) {
+        if (strv_isempty(l))
+                return l;
+
+        if (!path_strv_canonicalize(l))
+                return NULL;
+
+        return strv_uniq(l);
+}
+
+char *path_kill_slashes(char *path) {
+        char *f, *t;
+        bool slash = false;
+
+        /* Removes redundant inner and trailing slashes. Modifies the
+         * passed string in-place.
+         *
+         * ///foo///bar/ becomes /foo/bar
+         */
+
+        for (f = path, t = path; *f; f++) {
+
+                if (*f == '/') {
+                        slash = true;
+                        continue;
+                }
+
+                if (slash) {
+                        slash = false;
+                        *(t++) = '/';
+                }
+
+                *(t++) = *f;
+        }
+
+        /* Special rule, if we are talking of the root directory, a
+        trailing slash is good */
+
+        if (t == path && slash)
+                *(t++) = '/';
+
+        *t = 0;
+        return path;
+}
+
+bool path_equal(const char *a, const char *b) {
+        assert(a);
+        assert(b);
+
+        if ((a[0] == '/') != (b[0] == '/'))
+                return false;
+
+        for (;;) {
+                size_t j, k;
+
+                a += strspn(a, "/");
+                b += strspn(b, "/");
+
+                if (*a == 0 && *b == 0)
+                        return true;
+
+                if (*a == 0 || *b == 0)
+                        return false;
+
+                j = strcspn(a, "/");
+                k = strcspn(b, "/");
+
+                if (j != k)
+                        return false;
+
+                if (memcmp(a, b, j) != 0)
+                        return false;
+
+                a += j;
+                b += k;
+        }
+}
+
+int path_is_mount_point(const char *t, bool allow_symlink) {
+
+        union file_handle_union h = {
+                .handle.handle_bytes = MAX_HANDLE_SZ
+        };
+
+        int mount_id, mount_id_parent;
+        char *parent;
+        struct stat a, b;
+        int r;
+
+        /* We are not actually interested in the file handles, but
+         * name_to_handle_at() also passes us the mount ID, hence use
+         * it but throw the handle away */
+
+        if (path_equal(t, "/"))
+                return 1;
+
+        r = name_to_handle_at(AT_FDCWD, t, &h.handle, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
+        if (r < 0) {
+                if (errno == ENOSYS || errno == ENOTSUP)
+                        /* This kernel or file system does not support
+                         * name_to_handle_at(), hence fallback to the
+                         * traditional stat() logic */
+                        goto fallback;
+
+                if (errno == ENOENT)
+                        return 0;
+
+                return -errno;
+        }
+
+        r = path_get_parent(t, &parent);
+        if (r < 0)
+                return r;
+
+        h.handle.handle_bytes = MAX_HANDLE_SZ;
+        r = name_to_handle_at(AT_FDCWD, parent, &h.handle, &mount_id_parent, 0);
+        free(parent);
+        if (r < 0) {
+                /* The parent can't do name_to_handle_at() but the
+                 * directory we are interested in can? If so, it must
+                 * be a mount point */
+                if (errno == EOPNOTSUPP)
+                        return 1;
+
+                return -errno;
+        }
+
+        return mount_id != mount_id_parent;
+
+fallback:
+        if (allow_symlink)
+                r = stat(t, &a);
+        else
+                r = lstat(t, &a);
+
+        if (r < 0) {
+                if (errno == ENOENT)
+                        return 0;
+
+                return -errno;
+        }
+
+        r = path_get_parent(t, &parent);
+        if (r < 0)
+                return r;
+
+        r = lstat(parent, &b);
+        free(parent);
+        if (r < 0)
+                return -errno;
+
+        return a.st_dev != b.st_dev;
+}
+
+bool paths_check_timestamp(const char* const* paths, usec_t *timestamp, bool update) {
+        bool changed = false;
+        const char* const* i;
+
+        assert(timestamp);
+
+        if (paths == NULL)
+                return false;
+
+        STRV_FOREACH(i, paths) {
+                struct stat stats;
+                usec_t u;
+
+                if (stat(*i, &stats) < 0)
+                        continue;
+
+                u = timespec_load(&stats.st_mtim);
+
+                /* first check */
+                if (*timestamp >= u)
+                        continue;
+
+                log_debug("timestamp of '%s' changed", *i);
+
+                /* update timestamp */
+                if (update) {
+                        *timestamp = u;
+                        changed = true;
+                } else
+                        return true;
+        }
+
+        return changed;
+}