build-sys: split internal basic/ library from shared/

basic/      can be used by everything
            cannot use anything outside of basic/

libsystemd/ can use basic/
            cannot use shared/

shared/     can use libsystemd/

1 files changed, 853 insertions, 0 deletions

diff --git a/src/basic/path-util.c b/src/basic/path-util.c
new file mode 100644
index 0000000000..537705446a
--- /dev/null
+++ b/src/basic/path-util.c
@@ -0,0 +1,853 @@
+/*-*- 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 <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/statvfs.h>
+
+#include "macro.h"
+#include "util.h"
+#include "log.h"
+#include "strv.h"
+#include "path-util.h"
+#include "missing.h"
+#include "fileio.h"
+
+bool path_is_absolute(const char *p) {
+        return p[0] == '/';
+}
+
+bool is_path(const char *p) {
+        return !!strchr(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_split_and_make_absolute(const char *p) {
+        char **l;
+        assert(p);
+
+        l = strv_split(p, ":");
+        if (!l)
+                return NULL;
+
+        if (!path_strv_make_absolute_cwd(l)) {
+                strv_free(l);
+                return NULL;
+        }
+
+        return l;
+}
+
+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 strjoin(cwd, "/", p, NULL);
+}
+
+int path_make_relative(const char *from_dir, const char *to_path, char **_r) {
+        char *r, *p;
+        unsigned n_parents;
+
+        assert(from_dir);
+        assert(to_path);
+        assert(_r);
+
+        /* Strips the common part, and adds ".." elements as necessary. */
+
+        if (!path_is_absolute(from_dir))
+                return -EINVAL;
+
+        if (!path_is_absolute(to_path))
+                return -EINVAL;
+
+        /* Skip the common part. */
+        for (;;) {
+                size_t a;
+                size_t b;
+
+                from_dir += strspn(from_dir, "/");
+                to_path += strspn(to_path, "/");
+
+                if (!*from_dir) {
+                        if (!*to_path)
+                                /* from_dir equals to_path. */
+                                r = strdup(".");
+                        else
+                                /* from_dir is a parent directory of to_path. */
+                                r = strdup(to_path);
+
+                        if (!r)
+                                return -ENOMEM;
+
+                        path_kill_slashes(r);
+
+                        *_r = r;
+                        return 0;
+                }
+
+                if (!*to_path)
+                        break;
+
+                a = strcspn(from_dir, "/");
+                b = strcspn(to_path, "/");
+
+                if (a != b)
+                        break;
+
+                if (memcmp(from_dir, to_path, a) != 0)
+                        break;
+
+                from_dir += a;
+                to_path += b;
+        }
+
+        /* If we're here, then "from_dir" has one or more elements that need to
+         * be replaced with "..". */
+
+        /* Count the number of necessary ".." elements. */
+        for (n_parents = 0;;) {
+                from_dir += strspn(from_dir, "/");
+
+                if (!*from_dir)
+                        break;
+
+                from_dir += strcspn(from_dir, "/");
+                n_parents++;
+        }
+
+        r = malloc(n_parents * 3 + strlen(to_path) + 1);
+        if (!r)
+                return -ENOMEM;
+
+        for (p = r; n_parents > 0; n_parents--, p += 3)
+                memcpy(p, "../", 3);
+
+        strcpy(p, to_path);
+        path_kill_slashes(r);
+
+        *_r = r;
+        return 0;
+}
+
+char **path_strv_make_absolute_cwd(char **l) {
+        char **s;
+
+        /* Goes through every item in the string list and makes it
+         * absolute. This works in place and won't rollback any
+         * changes on failure. */
+
+        STRV_FOREACH(s, l) {
+                char *t;
+
+                t = path_make_absolute_cwd(*s);
+                if (!t)
+                        return NULL;
+
+                free(*s);
+                *s = t;
+        }
+
+        return l;
+}
+
+char **path_strv_resolve(char **l, const char *prefix) {
+        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;
+                _cleanup_free_ char *orig = NULL;
+
+                if (!path_is_absolute(*s)) {
+                        free(*s);
+                        continue;
+                }
+
+                if (prefix) {
+                        orig = *s;
+                        t = strappend(prefix, orig);
+                        if (!t) {
+                                enomem = true;
+                                continue;
+                        }
+                } else
+                        t = *s;
+
+                errno = 0;
+                u = canonicalize_file_name(t);
+                if (!u) {
+                        if (errno == ENOENT) {
+                                if (prefix) {
+                                        u = orig;
+                                        orig = NULL;
+                                        free(t);
+                                } else
+                                        u = t;
+                        } else {
+                                free(t);
+                                if (errno == ENOMEM || errno == 0)
+                                        enomem = true;
+
+                                continue;
+                        }
+                } else if (prefix) {
+                        char *x;
+
+                        free(t);
+                        x = path_startswith(u, prefix);
+                        if (x) {
+                                /* restore the slash if it was lost */
+                                if (!startswith(x, "/"))
+                                        *(--x) = '/';
+
+                                t = strdup(x);
+                                free(u);
+                                if (!t) {
+                                        enomem = true;
+                                        continue;
+                                }
+                                u = t;
+                        } else {
+                                /* canonicalized path goes outside of
+                                 * prefix, keep the original path instead */
+                                free(u);
+                                u = orig;
+                                orig = NULL;
+                        }
+                } else
+                        free(t);
+
+                l[k++] = u;
+        }
+
+        l[k] = NULL;
+
+        if (enomem)
+                return NULL;
+
+        return l;
+}
+
+char **path_strv_resolve_uniq(char **l, const char *prefix) {
+
+        if (strv_isempty(l))
+                return l;
+
+        if (!path_strv_resolve(l, prefix))
+                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;
+}
+
+char* path_startswith(const char *path, const char *prefix) {
+        assert(path);
+        assert(prefix);
+
+        if ((path[0] == '/') != (prefix[0] == '/'))
+                return NULL;
+
+        for (;;) {
+                size_t a, b;
+
+                path += strspn(path, "/");
+                prefix += strspn(prefix, "/");
+
+                if (*prefix == 0)
+                        return (char*) path;
+
+                if (*path == 0)
+                        return NULL;
+
+                a = strcspn(path, "/");
+                b = strcspn(prefix, "/");
+
+                if (a != b)
+                        return NULL;
+
+                if (memcmp(path, prefix, a) != 0)
+                        return NULL;
+
+                path += a;
+                prefix += b;
+        }
+}
+
+int path_compare(const char *a, const char *b) {
+        int d;
+
+        assert(a);
+        assert(b);
+
+        /* A relative path and an abolute path must not compare as equal.
+         * Which one is sorted before the other does not really matter.
+         * Here a relative path is ordered before an absolute path. */
+        d = (a[0] == '/') - (b[0] == '/');
+        if (d)
+                return d;
+
+        for (;;) {
+                size_t j, k;
+
+                a += strspn(a, "/");
+                b += strspn(b, "/");
+
+                if (*a == 0 && *b == 0)
+                        return 0;
+
+                /* Order prefixes first: "/foo" before "/foo/bar" */
+                if (*a == 0)
+                        return -1;
+                if (*b == 0)
+                        return 1;
+
+                j = strcspn(a, "/");
+                k = strcspn(b, "/");
+
+                /* Alphabetical sort: "/foo/aaa" before "/foo/b" */
+                d = memcmp(a, b, MIN(j, k));
+                if (d)
+                        return (d > 0) - (d < 0); /* sign of d */
+
+                /* Sort "/foo/a" before "/foo/aaa" */
+                d = (j > k) - (j < k);  /* sign of (j - k) */
+                if (d)
+                        return d;
+
+                a += j;
+                b += k;
+        }
+}
+
+bool path_equal(const char *a, const char *b) {
+        return path_compare(a, b) == 0;
+}
+
+bool path_equal_or_files_same(const char *a, const char *b) {
+        return path_equal(a, b) || files_same(a, b) > 0;
+}
+
+char* path_join(const char *root, const char *path, const char *rest) {
+        assert(path);
+
+        if (!isempty(root))
+                return strjoin(root, endswith(root, "/") ? "" : "/",
+                               path[0] == '/' ? path+1 : path,
+                               rest ? (endswith(path, "/") ? "" : "/") : NULL,
+                               rest && rest[0] == '/' ? rest+1 : rest,
+                               NULL);
+        else
+                return strjoin(path,
+                               rest ? (endswith(path, "/") ? "" : "/") : NULL,
+                               rest && rest[0] == '/' ? rest+1 : rest,
+                               NULL);
+}
+
+static int fd_fdinfo_mnt_id(int fd, const char *filename, int flags, int *mnt_id) {
+        char path[strlen("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
+        _cleanup_free_ char *fdinfo = NULL;
+        _cleanup_close_ int subfd = -1;
+        char *p;
+        int r;
+
+        if ((flags & AT_EMPTY_PATH) && isempty(filename))
+                xsprintf(path, "/proc/self/fdinfo/%i", fd);
+        else {
+                subfd = openat(fd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
+                if (subfd < 0)
+                        return -errno;
+
+                xsprintf(path, "/proc/self/fdinfo/%i", subfd);
+        }
+
+        r = read_full_file(path, &fdinfo, NULL);
+        if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */
+                return -EOPNOTSUPP;
+        if (r < 0)
+                return -errno;
+
+        p = startswith(fdinfo, "mnt_id:");
+        if (!p) {
+                p = strstr(fdinfo, "\nmnt_id:");
+                if (!p) /* The mnt_id field is a relatively new addition */
+                        return -EOPNOTSUPP;
+
+                p += 8;
+        }
+
+        p += strspn(p, WHITESPACE);
+        p[strcspn(p, WHITESPACE)] = 0;
+
+        return safe_atoi(p, mnt_id);
+}
+
+int fd_is_mount_point(int fd, const char *filename, int flags) {
+        union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
+        int mount_id = -1, mount_id_parent = -1;
+        bool nosupp = false, check_st_dev = true;
+        struct stat a, b;
+        int r;
+
+        assert(fd >= 0);
+        assert(filename);
+
+        /* First we will try the name_to_handle_at() syscall, which
+         * tells us the mount id and an opaque file "handle". It is
+         * not supported everywhere though (kernel compile-time
+         * option, not all file systems are hooked up). If it works
+         * the mount id is usually good enough to tell us whether
+         * something is a mount point.
+         *
+         * If that didn't work we will try to read the mount id from
+         * /proc/self/fdinfo/<fd>. This is almost as good as
+         * name_to_handle_at(), however, does not return the the
+         * opaque file handle. The opaque file handle is pretty useful
+         * to detect the root directory, which we should always
+         * consider a mount point. Hence we use this only as
+         * fallback. Exporting the mnt_id in fdinfo is a pretty recent
+         * kernel addition.
+         *
+         * As last fallback we do traditional fstat() based st_dev
+         * comparisons. This is how things were traditionally done,
+         * but unionfs breaks breaks this since it exposes file
+         * systems with a variety of st_dev reported. Also, btrfs
+         * subvolumes have different st_dev, even though they aren't
+         * real mounts of their own. */
+
+        r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags);
+        if (r < 0) {
+                if (errno == ENOSYS)
+                        /* This kernel does not support name_to_handle_at()
+                         * fall back to simpler logic. */
+                        goto fallback_fdinfo;
+                else if (errno == EOPNOTSUPP)
+                        /* This kernel or file system does not support
+                         * name_to_handle_at(), hence let's see if the
+                         * upper fs supports it (in which case it is a
+                         * mount point), otherwise fallback to the
+                         * traditional stat() logic */
+                        nosupp = true;
+                else
+                        return -errno;
+        }
+
+        r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH);
+        if (r < 0) {
+                if (errno == EOPNOTSUPP) {
+                        if (nosupp)
+                                /* Neither parent nor child do name_to_handle_at()?
+                                   We have no choice but to fall back. */
+                                goto fallback_fdinfo;
+                        else
+                                /* 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. */
+                                return 1;
+                } else
+                        return -errno;
+        }
+
+        /* The parent can do name_to_handle_at() but the
+         * directory we are interested in can't? If so, it
+         * must be a mount point. */
+        if (nosupp)
+                return 1;
+
+        /* If the file handle for the directory we are
+         * interested in and its parent are identical, we
+         * assume this is the root directory, which is a mount
+         * point. */
+
+        if (h.handle.handle_bytes == h_parent.handle.handle_bytes &&
+            h.handle.handle_type == h_parent.handle.handle_type &&
+            memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0)
+                return 1;
+
+        return mount_id != mount_id_parent;
+
+fallback_fdinfo:
+        r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
+        if (r == -EOPNOTSUPP)
+                goto fallback_fstat;
+        if (r < 0)
+                return r;
+
+        r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent);
+        if (r < 0)
+                return r;
+
+        if (mount_id != mount_id_parent)
+                return 1;
+
+        /* Hmm, so, the mount ids are the same. This leaves one
+         * special case though for the root file system. For that,
+         * let's see if the parent directory has the same inode as we
+         * are interested in. Hence, let's also do fstat() checks now,
+         * too, but avoid the st_dev comparisons, since they aren't
+         * that useful on unionfs mounts. */
+        check_st_dev = false;
+
+fallback_fstat:
+        /* yay for fstatat() taking a different set of flags than the other
+         * _at() above */
+        if (flags & AT_SYMLINK_FOLLOW)
+                flags &= ~AT_SYMLINK_FOLLOW;
+        else
+                flags |= AT_SYMLINK_NOFOLLOW;
+        if (fstatat(fd, filename, &a, flags) < 0)
+                return -errno;
+
+        if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0)
+                return -errno;
+
+        /* A directory with same device and inode as its parent? Must
+         * be the root directory */
+        if (a.st_dev == b.st_dev &&
+            a.st_ino == b.st_ino)
+                return 1;
+
+        return check_st_dev && (a.st_dev != b.st_dev);
+}
+
+/* flags can be AT_SYMLINK_FOLLOW or 0 */
+int path_is_mount_point(const char *t, int flags) {
+        _cleanup_close_ int fd = -1;
+        _cleanup_free_ char *canonical = NULL, *parent = NULL;
+        int r;
+
+        assert(t);
+
+        if (path_equal(t, "/"))
+                return 1;
+
+        /* we need to resolve symlinks manually, we can't just rely on
+         * fd_is_mount_point() to do that for us; if we have a structure like
+         * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
+         * look at needs to be /usr, not /. */
+        if (flags & AT_SYMLINK_FOLLOW) {
+                canonical = canonicalize_file_name(t);
+                if (!canonical)
+                        return -errno;
+        }
+
+        r = path_get_parent(canonical ?: t, &parent);
+        if (r < 0)
+                return r;
+
+        fd = openat(AT_FDCWD, parent, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_PATH);
+        if (fd < 0)
+                return -errno;
+
+        return fd_is_mount_point(fd, basename(canonical ?: t), flags);
+}
+
+int path_is_read_only_fs(const char *path) {
+        struct statvfs st;
+
+        assert(path);
+
+        if (statvfs(path, &st) < 0)
+                return -errno;
+
+        if (st.f_flag & ST_RDONLY)
+                return true;
+
+        /* On NFS, statvfs() might not reflect whether we can actually
+         * write to the remote share. Let's try again with
+         * access(W_OK) which is more reliable, at least sometimes. */
+        if (access(path, W_OK) < 0 && errno == EROFS)
+                return true;
+
+        return false;
+}
+
+int path_is_os_tree(const char *path) {
+        char *p;
+        int r;
+
+        /* We use /usr/lib/os-release as flag file if something is an OS */
+        p = strjoina(path, "/usr/lib/os-release");
+        r = access(p, F_OK);
+
+        if (r >= 0)
+                return 1;
+
+        /* Also check for the old location in /etc, just in case. */
+        p = strjoina(path, "/etc/os-release");
+        r = access(p, F_OK);
+
+        return r >= 0;
+}
+
+int find_binary(const char *name, bool local, char **filename) {
+        assert(name);
+
+        if (is_path(name)) {
+                if (local && access(name, X_OK) < 0)
+                        return -errno;
+
+                if (filename) {
+                        char *p;
+
+                        p = path_make_absolute_cwd(name);
+                        if (!p)
+                                return -ENOMEM;
+
+                        *filename = p;
+                }
+
+                return 0;
+        } else {
+                const char *path;
+                const char *word, *state;
+                size_t l;
+
+                /**
+                 * Plain getenv, not secure_getenv, because we want
+                 * to actually allow the user to pick the binary.
+                 */
+                path = getenv("PATH");
+                if (!path)
+                        path = DEFAULT_PATH;
+
+                FOREACH_WORD_SEPARATOR(word, l, path, ":", state) {
+                        _cleanup_free_ char *p = NULL;
+
+                        if (asprintf(&p, "%.*s/%s", (int) l, word, name) < 0)
+                                return -ENOMEM;
+
+                        if (access(p, X_OK) < 0)
+                                continue;
+
+                        if (filename) {
+                                *filename = path_kill_slashes(p);
+                                p = NULL;
+                        }
+
+                        return 0;
+                }
+
+                return -ENOENT;
+        }
+}
+
+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;
+}
+
+int fsck_exists(const char *fstype) {
+        _cleanup_free_ char *p = NULL, *d = NULL;
+        const char *checker;
+        int r;
+
+        checker = strjoina("fsck.", fstype);
+
+        r = find_binary(checker, true, &p);
+        if (r < 0)
+                return r;
+
+        /* An fsck that is linked to /bin/true is a non-existent
+         * fsck */
+
+        r = readlink_malloc(p, &d);
+        if (r >= 0 &&
+            (path_equal(d, "/bin/true") ||
+             path_equal(d, "/usr/bin/true") ||
+             path_equal(d, "/dev/null")))
+                return -ENOENT;
+
+        return 0;
+}
+
+char *prefix_root(const char *root, const char *path) {
+        char *n, *p;
+        size_t l;
+
+        /* If root is passed, prefixes path with it. Otherwise returns
+         * it as is. */
+
+        assert(path);
+
+        /* First, drop duplicate prefixing slashes from the path */
+        while (path[0] == '/' && path[1] == '/')
+                path++;
+
+        if (isempty(root) || path_equal(root, "/"))
+                return strdup(path);
+
+        l = strlen(root) + 1 + strlen(path) + 1;
+
+        n = new(char, l);
+        if (!n)
+                return NULL;
+
+        p = stpcpy(n, root);
+
+        while (p > n && p[-1] == '/')
+                p--;
+
+        if (path[0] != '/')
+                *(p++) = '/';
+
+        strcpy(p, path);
+        return n;
+}