stuff

1 files changed, 1280 insertions, 0 deletions

diff --git a/src/libbasic/fileio.c b/src/libbasic/fileio.c
new file mode 100644
index 0000000000..e43ca6d29e
--- /dev/null
+++ b/src/libbasic/fileio.c
@@ -0,0 +1,1280 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2010 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 <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "ctype.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "log.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "random-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "umask-util.h"
+#include "utf8.h"
+
+int write_string_stream(FILE *f, const char *line, bool enforce_newline) {
+
+        assert(f);
+        assert(line);
+
+        fputs(line, f);
+        if (enforce_newline && !endswith(line, "\n"))
+                fputc('\n', f);
+
+        return fflush_and_check(f);
+}
+
+static int write_string_file_atomic(const char *fn, const char *line, bool enforce_newline) {
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        assert(fn);
+        assert(line);
+
+        r = fopen_temporary(fn, &f, &p);
+        if (r < 0)
+                return r;
+
+        (void) fchmod_umask(fileno(f), 0644);
+
+        r = write_string_stream(f, line, enforce_newline);
+        if (r >= 0) {
+                if (rename(p, fn) < 0)
+                        r = -errno;
+        }
+
+        if (r < 0)
+                (void) unlink(p);
+
+        return r;
+}
+
+int write_string_file(const char *fn, const char *line, WriteStringFileFlags flags) {
+        _cleanup_fclose_ FILE *f = NULL;
+        int q, r;
+
+        assert(fn);
+        assert(line);
+
+        if (flags & WRITE_STRING_FILE_ATOMIC) {
+                assert(flags & WRITE_STRING_FILE_CREATE);
+
+                r = write_string_file_atomic(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
+                if (r < 0)
+                        goto fail;
+
+                return r;
+        }
+
+        if (flags & WRITE_STRING_FILE_CREATE) {
+                f = fopen(fn, "we");
+                if (!f) {
+                        r = -errno;
+                        goto fail;
+                }
+        } else {
+                int fd;
+
+                /* We manually build our own version of fopen(..., "we") that
+                 * works without O_CREAT */
+                fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY);
+                if (fd < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+
+                f = fdopen(fd, "we");
+                if (!f) {
+                        r = -errno;
+                        safe_close(fd);
+                        goto fail;
+                }
+        }
+
+        r = write_string_stream(f, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        if (!(flags & WRITE_STRING_FILE_VERIFY_ON_FAILURE))
+                return r;
+
+        f = safe_fclose(f);
+
+        /* OK, the operation failed, but let's see if the right
+         * contents in place already. If so, eat up the error. */
+
+        q = verify_file(fn, line, !(flags & WRITE_STRING_FILE_AVOID_NEWLINE));
+        if (q <= 0)
+                return r;
+
+        return 0;
+}
+
+int read_one_line_file(const char *fn, char **line) {
+        _cleanup_fclose_ FILE *f = NULL;
+        char t[LINE_MAX], *c;
+
+        assert(fn);
+        assert(line);
+
+        f = fopen(fn, "re");
+        if (!f)
+                return -errno;
+
+        if (!fgets(t, sizeof(t), f)) {
+
+                if (ferror(f))
+                        return errno > 0 ? -errno : -EIO;
+
+                t[0] = 0;
+        }
+
+        c = strdup(t);
+        if (!c)
+                return -ENOMEM;
+        truncate_nl(c);
+
+        *line = c;
+        return 0;
+}
+
+int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *buf = NULL;
+        size_t l, k;
+
+        assert(fn);
+        assert(blob);
+
+        l = strlen(blob);
+
+        if (accept_extra_nl && endswith(blob, "\n"))
+                accept_extra_nl = false;
+
+        buf = malloc(l + accept_extra_nl + 1);
+        if (!buf)
+                return -ENOMEM;
+
+        f = fopen(fn, "re");
+        if (!f)
+                return -errno;
+
+        /* We try to read one byte more than we need, so that we know whether we hit eof */
+        errno = 0;
+        k = fread(buf, 1, l + accept_extra_nl + 1, f);
+        if (ferror(f))
+                return errno > 0 ? -errno : -EIO;
+
+        if (k != l && k != l + accept_extra_nl)
+                return 0;
+        if (memcmp(buf, blob, l) != 0)
+                return 0;
+        if (k > l && buf[l] != '\n')
+                return 0;
+
+        return 1;
+}
+
+int read_full_stream(FILE *f, char **contents, size_t *size) {
+        size_t n, l;
+        _cleanup_free_ char *buf = NULL;
+        struct stat st;
+
+        assert(f);
+        assert(contents);
+
+        if (fstat(fileno(f), &st) < 0)
+                return -errno;
+
+        n = LINE_MAX;
+
+        if (S_ISREG(st.st_mode)) {
+
+                /* Safety check */
+                if (st.st_size > 4*1024*1024)
+                        return -E2BIG;
+
+                /* Start with the right file size, but be prepared for
+                 * files from /proc which generally report a file size
+                 * of 0 */
+                if (st.st_size > 0)
+                        n = st.st_size;
+        }
+
+        l = 0;
+        for (;;) {
+                char *t;
+                size_t k;
+
+                t = realloc(buf, n+1);
+                if (!t)
+                        return -ENOMEM;
+
+                buf = t;
+                k = fread(buf + l, 1, n - l, f);
+
+                if (k <= 0) {
+                        if (ferror(f))
+                                return -errno;
+
+                        break;
+                }
+
+                l += k;
+                n *= 2;
+
+                /* Safety check */
+                if (n > 4*1024*1024)
+                        return -E2BIG;
+        }
+
+        buf[l] = 0;
+        *contents = buf;
+        buf = NULL; /* do not free */
+
+        if (size)
+                *size = l;
+
+        return 0;
+}
+
+int read_full_file(const char *fn, char **contents, size_t *size) {
+        _cleanup_fclose_ FILE *f = NULL;
+
+        assert(fn);
+        assert(contents);
+
+        f = fopen(fn, "re");
+        if (!f)
+                return -errno;
+
+        return read_full_stream(f, contents, size);
+}
+
+static int parse_env_file_internal(
+                FILE *f,
+                const char *fname,
+                const char *newline,
+                int (*push) (const char *filename, unsigned line,
+                             const char *key, char *value, void *userdata, int *n_pushed),
+                void *userdata,
+                int *n_pushed) {
+
+        _cleanup_free_ char *contents = NULL, *key = NULL;
+        size_t key_alloc = 0, n_key = 0, value_alloc = 0, n_value = 0, last_value_whitespace = (size_t) -1, last_key_whitespace = (size_t) -1;
+        char *p, *value = NULL;
+        int r;
+        unsigned line = 1;
+
+        enum {
+                PRE_KEY,
+                KEY,
+                PRE_VALUE,
+                VALUE,
+                VALUE_ESCAPE,
+                SINGLE_QUOTE_VALUE,
+                SINGLE_QUOTE_VALUE_ESCAPE,
+                DOUBLE_QUOTE_VALUE,
+                DOUBLE_QUOTE_VALUE_ESCAPE,
+                COMMENT,
+                COMMENT_ESCAPE
+        } state = PRE_KEY;
+
+        assert(newline);
+
+        if (f)
+                r = read_full_stream(f, &contents, NULL);
+        else
+                r = read_full_file(fname, &contents, NULL);
+        if (r < 0)
+                return r;
+
+        for (p = contents; *p; p++) {
+                char c = *p;
+
+                switch (state) {
+
+                case PRE_KEY:
+                        if (strchr(COMMENTS, c))
+                                state = COMMENT;
+                        else if (!strchr(WHITESPACE, c)) {
+                                state = KEY;
+                                last_key_whitespace = (size_t) -1;
+
+                                if (!GREEDY_REALLOC(key, key_alloc, n_key+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                key[n_key++] = c;
+                        }
+                        break;
+
+                case KEY:
+                        if (strchr(newline, c)) {
+                                state = PRE_KEY;
+                                line ++;
+                                n_key = 0;
+                        } else if (c == '=') {
+                                state = PRE_VALUE;
+                                last_value_whitespace = (size_t) -1;
+                        } else {
+                                if (!strchr(WHITESPACE, c))
+                                        last_key_whitespace = (size_t) -1;
+                                else if (last_key_whitespace == (size_t) -1)
+                                         last_key_whitespace = n_key;
+
+                                if (!GREEDY_REALLOC(key, key_alloc, n_key+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                key[n_key++] = c;
+                        }
+
+                        break;
+
+                case PRE_VALUE:
+                        if (strchr(newline, c)) {
+                                state = PRE_KEY;
+                                line ++;
+                                key[n_key] = 0;
+
+                                if (value)
+                                        value[n_value] = 0;
+
+                                /* strip trailing whitespace from key */
+                                if (last_key_whitespace != (size_t) -1)
+                                        key[last_key_whitespace] = 0;
+
+                                r = push(fname, line, key, value, userdata, n_pushed);
+                                if (r < 0)
+                                        goto fail;
+
+                                n_key = 0;
+                                value = NULL;
+                                value_alloc = n_value = 0;
+
+                        } else if (c == '\'')
+                                state = SINGLE_QUOTE_VALUE;
+                        else if (c == '\"')
+                                state = DOUBLE_QUOTE_VALUE;
+                        else if (c == '\\')
+                                state = VALUE_ESCAPE;
+                        else if (!strchr(WHITESPACE, c)) {
+                                state = VALUE;
+
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+
+                        break;
+
+                case VALUE:
+                        if (strchr(newline, c)) {
+                                state = PRE_KEY;
+                                line ++;
+
+                                key[n_key] = 0;
+
+                                if (value)
+                                        value[n_value] = 0;
+
+                                /* Chomp off trailing whitespace from value */
+                                if (last_value_whitespace != (size_t) -1)
+                                        value[last_value_whitespace] = 0;
+
+                                /* strip trailing whitespace from key */
+                                if (last_key_whitespace != (size_t) -1)
+                                        key[last_key_whitespace] = 0;
+
+                                r = push(fname, line, key, value, userdata, n_pushed);
+                                if (r < 0)
+                                        goto fail;
+
+                                n_key = 0;
+                                value = NULL;
+                                value_alloc = n_value = 0;
+
+                        } else if (c == '\\') {
+                                state = VALUE_ESCAPE;
+                                last_value_whitespace = (size_t) -1;
+                        } else {
+                                if (!strchr(WHITESPACE, c))
+                                        last_value_whitespace = (size_t) -1;
+                                else if (last_value_whitespace == (size_t) -1)
+                                        last_value_whitespace = n_value;
+
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+
+                        break;
+
+                case VALUE_ESCAPE:
+                        state = VALUE;
+
+                        if (!strchr(newline, c)) {
+                                /* Escaped newlines we eat up entirely */
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+                        break;
+
+                case SINGLE_QUOTE_VALUE:
+                        if (c == '\'')
+                                state = PRE_VALUE;
+                        else if (c == '\\')
+                                state = SINGLE_QUOTE_VALUE_ESCAPE;
+                        else {
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+
+                        break;
+
+                case SINGLE_QUOTE_VALUE_ESCAPE:
+                        state = SINGLE_QUOTE_VALUE;
+
+                        if (!strchr(newline, c)) {
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+                        break;
+
+                case DOUBLE_QUOTE_VALUE:
+                        if (c == '\"')
+                                state = PRE_VALUE;
+                        else if (c == '\\')
+                                state = DOUBLE_QUOTE_VALUE_ESCAPE;
+                        else {
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+
+                        break;
+
+                case DOUBLE_QUOTE_VALUE_ESCAPE:
+                        state = DOUBLE_QUOTE_VALUE;
+
+                        if (!strchr(newline, c)) {
+                                if (!GREEDY_REALLOC(value, value_alloc, n_value+2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                value[n_value++] = c;
+                        }
+                        break;
+
+                case COMMENT:
+                        if (c == '\\')
+                                state = COMMENT_ESCAPE;
+                        else if (strchr(newline, c)) {
+                                state = PRE_KEY;
+                                line ++;
+                        }
+                        break;
+
+                case COMMENT_ESCAPE:
+                        state = COMMENT;
+                        break;
+                }
+        }
+
+        if (state == PRE_VALUE ||
+            state == VALUE ||
+            state == VALUE_ESCAPE ||
+            state == SINGLE_QUOTE_VALUE ||
+            state == SINGLE_QUOTE_VALUE_ESCAPE ||
+            state == DOUBLE_QUOTE_VALUE ||
+            state == DOUBLE_QUOTE_VALUE_ESCAPE) {
+
+                key[n_key] = 0;
+
+                if (value)
+                        value[n_value] = 0;
+
+                if (state == VALUE)
+                        if (last_value_whitespace != (size_t) -1)
+                                value[last_value_whitespace] = 0;
+
+                /* strip trailing whitespace from key */
+                if (last_key_whitespace != (size_t) -1)
+                        key[last_key_whitespace] = 0;
+
+                r = push(fname, line, key, value, userdata, n_pushed);
+                if (r < 0)
+                        goto fail;
+        }
+
+        return 0;
+
+fail:
+        free(value);
+        return r;
+}
+
+static int parse_env_file_push(
+                const char *filename, unsigned line,
+                const char *key, char *value,
+                void *userdata,
+                int *n_pushed) {
+
+        const char *k;
+        va_list aq, *ap = userdata;
+
+        if (!utf8_is_valid(key)) {
+                _cleanup_free_ char *p;
+
+                p = utf8_escape_invalid(key);
+                log_error("%s:%u: invalid UTF-8 in key '%s', ignoring.", strna(filename), line, p);
+                return -EINVAL;
+        }
+
+        if (value && !utf8_is_valid(value)) {
+                _cleanup_free_ char *p;
+
+                p = utf8_escape_invalid(value);
+                log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, p);
+                return -EINVAL;
+        }
+
+        va_copy(aq, *ap);
+
+        while ((k = va_arg(aq, const char *))) {
+                char **v;
+
+                v = va_arg(aq, char **);
+
+                if (streq(key, k)) {
+                        va_end(aq);
+                        free(*v);
+                        *v = value;
+
+                        if (n_pushed)
+                                (*n_pushed)++;
+
+                        return 1;
+                }
+        }
+
+        va_end(aq);
+        free(value);
+
+        return 0;
+}
+
+int parse_env_file(
+                const char *fname,
+                const char *newline, ...) {
+
+        va_list ap;
+        int r, n_pushed = 0;
+
+        if (!newline)
+                newline = NEWLINE;
+
+        va_start(ap, newline);
+        r = parse_env_file_internal(NULL, fname, newline, parse_env_file_push, &ap, &n_pushed);
+        va_end(ap);
+
+        return r < 0 ? r : n_pushed;
+}
+
+static int load_env_file_push(
+                const char *filename, unsigned line,
+                const char *key, char *value,
+                void *userdata,
+                int *n_pushed) {
+        char ***m = userdata;
+        char *p;
+        int r;
+
+        if (!utf8_is_valid(key)) {
+                _cleanup_free_ char *t = utf8_escape_invalid(key);
+
+                log_error("%s:%u: invalid UTF-8 for key '%s', ignoring.", strna(filename), line, t);
+                return -EINVAL;
+        }
+
+        if (value && !utf8_is_valid(value)) {
+                _cleanup_free_ char *t = utf8_escape_invalid(value);
+
+                log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, t);
+                return -EINVAL;
+        }
+
+        p = strjoin(key, "=", strempty(value), NULL);
+        if (!p)
+                return -ENOMEM;
+
+        r = strv_consume(m, p);
+        if (r < 0)
+                return r;
+
+        if (n_pushed)
+                (*n_pushed)++;
+
+        free(value);
+        return 0;
+}
+
+int load_env_file(FILE *f, const char *fname, const char *newline, char ***rl) {
+        char **m = NULL;
+        int r;
+
+        if (!newline)
+                newline = NEWLINE;
+
+        r = parse_env_file_internal(f, fname, newline, load_env_file_push, &m, NULL);
+        if (r < 0) {
+                strv_free(m);
+                return r;
+        }
+
+        *rl = m;
+        return 0;
+}
+
+static int load_env_file_push_pairs(
+                const char *filename, unsigned line,
+                const char *key, char *value,
+                void *userdata,
+                int *n_pushed) {
+        char ***m = userdata;
+        int r;
+
+        if (!utf8_is_valid(key)) {
+                _cleanup_free_ char *t = utf8_escape_invalid(key);
+
+                log_error("%s:%u: invalid UTF-8 for key '%s', ignoring.", strna(filename), line, t);
+                return -EINVAL;
+        }
+
+        if (value && !utf8_is_valid(value)) {
+                _cleanup_free_ char *t = utf8_escape_invalid(value);
+
+                log_error("%s:%u: invalid UTF-8 value for key %s: '%s', ignoring.", strna(filename), line, key, t);
+                return -EINVAL;
+        }
+
+        r = strv_extend(m, key);
+        if (r < 0)
+                return -ENOMEM;
+
+        if (!value) {
+                r = strv_extend(m, "");
+                if (r < 0)
+                        return -ENOMEM;
+        } else {
+                r = strv_push(m, value);
+                if (r < 0)
+                        return r;
+        }
+
+        if (n_pushed)
+                (*n_pushed)++;
+
+        return 0;
+}
+
+int load_env_file_pairs(FILE *f, const char *fname, const char *newline, char ***rl) {
+        char **m = NULL;
+        int r;
+
+        if (!newline)
+                newline = NEWLINE;
+
+        r = parse_env_file_internal(f, fname, newline, load_env_file_push_pairs, &m, NULL);
+        if (r < 0) {
+                strv_free(m);
+                return r;
+        }
+
+        *rl = m;
+        return 0;
+}
+
+static void write_env_var(FILE *f, const char *v) {
+        const char *p;
+
+        p = strchr(v, '=');
+        if (!p) {
+                /* Fallback */
+                fputs(v, f);
+                fputc('\n', f);
+                return;
+        }
+
+        p++;
+        fwrite(v, 1, p-v, f);
+
+        if (string_has_cc(p, NULL) || chars_intersect(p, WHITESPACE SHELL_NEED_QUOTES)) {
+                fputc('\"', f);
+
+                for (; *p; p++) {
+                        if (strchr(SHELL_NEED_ESCAPE, *p))
+                                fputc('\\', f);
+
+                        fputc(*p, f);
+                }
+
+                fputc('\"', f);
+        } else
+                fputs(p, f);
+
+        fputc('\n', f);
+}
+
+int write_env_file(const char *fname, char **l) {
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *p = NULL;
+        char **i;
+        int r;
+
+        assert(fname);
+
+        r = fopen_temporary(fname, &f, &p);
+        if (r < 0)
+                return r;
+
+        fchmod_umask(fileno(f), 0644);
+
+        STRV_FOREACH(i, l)
+                write_env_var(f, *i);
+
+        r = fflush_and_check(f);
+        if (r >= 0) {
+                if (rename(p, fname) >= 0)
+                        return 0;
+
+                r = -errno;
+        }
+
+        unlink(p);
+        return r;
+}
+
+int executable_is_script(const char *path, char **interpreter) {
+        int r;
+        _cleanup_free_ char *line = NULL;
+        int len;
+        char *ans;
+
+        assert(path);
+
+        r = read_one_line_file(path, &line);
+        if (r < 0)
+                return r;
+
+        if (!startswith(line, "#!"))
+                return 0;
+
+        ans = strstrip(line + 2);
+        len = strcspn(ans, " \t");
+
+        if (len == 0)
+                return 0;
+
+        ans = strndup(ans, len);
+        if (!ans)
+                return -ENOMEM;
+
+        *interpreter = ans;
+        return 1;
+}
+
+/**
+ * Retrieve one field from a file like /proc/self/status.  pattern
+ * should not include whitespace or the delimiter (':'). pattern matches only
+ * the beginning of a line. Whitespace before ':' is skipped. Whitespace and
+ * zeros after the ':' will be skipped. field must be freed afterwards.
+ * terminator specifies the terminating characters of the field value (not
+ * included in the value).
+ */
+int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field) {
+        _cleanup_free_ char *status = NULL;
+        char *t, *f;
+        size_t len;
+        int r;
+
+        assert(terminator);
+        assert(filename);
+        assert(pattern);
+        assert(field);
+
+        r = read_full_file(filename, &status, NULL);
+        if (r < 0)
+                return r;
+
+        t = status;
+
+        do {
+                bool pattern_ok;
+
+                do {
+                        t = strstr(t, pattern);
+                        if (!t)
+                                return -ENOENT;
+
+                        /* Check that pattern occurs in beginning of line. */
+                        pattern_ok = (t == status || t[-1] == '\n');
+
+                        t += strlen(pattern);
+
+                } while (!pattern_ok);
+
+                t += strspn(t, " \t");
+                if (!*t)
+                        return -ENOENT;
+
+        } while (*t != ':');
+
+        t++;
+
+        if (*t) {
+                t += strspn(t, " \t");
+
+                /* Also skip zeros, because when this is used for
+                 * capabilities, we don't want the zeros. This way the
+                 * same capability set always maps to the same string,
+                 * irrespective of the total capability set size. For
+                 * other numbers it shouldn't matter. */
+                t += strspn(t, "0");
+                /* Back off one char if there's nothing but whitespace
+                   and zeros */
+                if (!*t || isspace(*t))
+                        t --;
+        }
+
+        len = strcspn(t, terminator);
+
+        f = strndup(t, len);
+        if (!f)
+                return -ENOMEM;
+
+        *field = f;
+        return 0;
+}
+
+DIR *xopendirat(int fd, const char *name, int flags) {
+        int nfd;
+        DIR *d;
+
+        assert(!(flags & O_CREAT));
+
+        nfd = openat(fd, name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|flags, 0);
+        if (nfd < 0)
+                return NULL;
+
+        d = fdopendir(nfd);
+        if (!d) {
+                safe_close(nfd);
+                return NULL;
+        }
+
+        return d;
+}
+
+static int search_and_fopen_internal(const char *path, const char *mode, const char *root, char **search, FILE **_f) {
+        char **i;
+
+        assert(path);
+        assert(mode);
+        assert(_f);
+
+        if (!path_strv_resolve_uniq(search, root))
+                return -ENOMEM;
+
+        STRV_FOREACH(i, search) {
+                _cleanup_free_ char *p = NULL;
+                FILE *f;
+
+                if (root)
+                        p = strjoin(root, *i, "/", path, NULL);
+                else
+                        p = strjoin(*i, "/", path, NULL);
+                if (!p)
+                        return -ENOMEM;
+
+                f = fopen(p, mode);
+                if (f) {
+                        *_f = f;
+                        return 0;
+                }
+
+                if (errno != ENOENT)
+                        return -errno;
+        }
+
+        return -ENOENT;
+}
+
+int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f) {
+        _cleanup_strv_free_ char **copy = NULL;
+
+        assert(path);
+        assert(mode);
+        assert(_f);
+
+        if (path_is_absolute(path)) {
+                FILE *f;
+
+                f = fopen(path, mode);
+                if (f) {
+                        *_f = f;
+                        return 0;
+                }
+
+                return -errno;
+        }
+
+        copy = strv_copy((char**) search);
+        if (!copy)
+                return -ENOMEM;
+
+        return search_and_fopen_internal(path, mode, root, copy, _f);
+}
+
+int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f) {
+        _cleanup_strv_free_ char **s = NULL;
+
+        if (path_is_absolute(path)) {
+                FILE *f;
+
+                f = fopen(path, mode);
+                if (f) {
+                        *_f = f;
+                        return 0;
+                }
+
+                return -errno;
+        }
+
+        s = strv_split_nulstr(search);
+        if (!s)
+                return -ENOMEM;
+
+        return search_and_fopen_internal(path, mode, root, s, _f);
+}
+
+int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
+        FILE *f;
+        char *t;
+        int r, fd;
+
+        assert(path);
+        assert(_f);
+        assert(_temp_path);
+
+        r = tempfn_xxxxxx(path, NULL, &t);
+        if (r < 0)
+                return r;
+
+        fd = mkostemp_safe(t, O_WRONLY|O_CLOEXEC);
+        if (fd < 0) {
+                free(t);
+                return -errno;
+        }
+
+        f = fdopen(fd, "we");
+        if (!f) {
+                unlink_noerrno(t);
+                free(t);
+                safe_close(fd);
+                return -errno;
+        }
+
+        *_f = f;
+        *_temp_path = t;
+
+        return 0;
+}
+
+int fflush_and_check(FILE *f) {
+        assert(f);
+
+        errno = 0;
+        fflush(f);
+
+        if (ferror(f))
+                return errno > 0 ? -errno : -EIO;
+
+        return 0;
+}
+
+/* This is much like like mkostemp() but is subject to umask(). */
+int mkostemp_safe(char *pattern, int flags) {
+        _cleanup_umask_ mode_t u;
+        int fd;
+
+        assert(pattern);
+
+        u = umask(077);
+
+        fd = mkostemp(pattern, flags);
+        if (fd < 0)
+                return -errno;
+
+        return fd;
+}
+
+int open_tmpfile(const char *path, int flags) {
+        char *p;
+        int fd;
+
+        assert(path);
+
+#ifdef O_TMPFILE
+        /* Try O_TMPFILE first, if it is supported */
+        fd = open(path, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR);
+        if (fd >= 0)
+                return fd;
+#endif
+
+        /* Fall back to unguessable name + unlinking */
+        p = strjoina(path, "/systemd-tmp-XXXXXX");
+
+        fd = mkostemp_safe(p, flags);
+        if (fd < 0)
+                return fd;
+
+        unlink(p);
+        return fd;
+}
+
+int tempfn_xxxxxx(const char *p, const char *extra, char **ret) {
+        const char *fn;
+        char *t;
+
+        assert(p);
+        assert(ret);
+
+        /*
+         * Turns this:
+         *         /foo/bar/waldo
+         *
+         * Into this:
+         *         /foo/bar/.#<extra>waldoXXXXXX
+         */
+
+        fn = basename(p);
+        if (!filename_is_valid(fn))
+                return -EINVAL;
+
+        if (extra == NULL)
+                extra = "";
+
+        t = new(char, strlen(p) + 2 + strlen(extra) + 6 + 1);
+        if (!t)
+                return -ENOMEM;
+
+        strcpy(stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn), "XXXXXX");
+
+        *ret = path_kill_slashes(t);
+        return 0;
+}
+
+int tempfn_random(const char *p, const char *extra, char **ret) {
+        const char *fn;
+        char *t, *x;
+        uint64_t u;
+        unsigned i;
+
+        assert(p);
+        assert(ret);
+
+        /*
+         * Turns this:
+         *         /foo/bar/waldo
+         *
+         * Into this:
+         *         /foo/bar/.#<extra>waldobaa2a261115984a9
+         */
+
+        fn = basename(p);
+        if (!filename_is_valid(fn))
+                return -EINVAL;
+
+        if (!extra)
+                extra = "";
+
+        t = new(char, strlen(p) + 2 + strlen(extra) + 16 + 1);
+        if (!t)
+                return -ENOMEM;
+
+        x = stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), extra), fn);
+
+        u = random_u64();
+        for (i = 0; i < 16; i++) {
+                *(x++) = hexchar(u & 0xF);
+                u >>= 4;
+        }
+
+        *x = 0;
+
+        *ret = path_kill_slashes(t);
+        return 0;
+}
+
+int tempfn_random_child(const char *p, const char *extra, char **ret) {
+        char *t, *x;
+        uint64_t u;
+        unsigned i;
+
+        assert(p);
+        assert(ret);
+
+        /* Turns this:
+         *         /foo/bar/waldo
+         * Into this:
+         *         /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0
+         */
+
+        if (!extra)
+                extra = "";
+
+        t = new(char, strlen(p) + 3 + strlen(extra) + 16 + 1);
+        if (!t)
+                return -ENOMEM;
+
+        x = stpcpy(stpcpy(stpcpy(t, p), "/.#"), extra);
+
+        u = random_u64();
+        for (i = 0; i < 16; i++) {
+                *(x++) = hexchar(u & 0xF);
+                u >>= 4;
+        }
+
+        *x = 0;
+
+        *ret = path_kill_slashes(t);
+        return 0;
+}
+
+int write_timestamp_file_atomic(const char *fn, usec_t n) {
+        char ln[DECIMAL_STR_MAX(n)+2];
+
+        /* Creates a "timestamp" file, that contains nothing but a
+         * usec_t timestamp, formatted in ASCII. */
+
+        if (n <= 0 || n >= USEC_INFINITY)
+                return -ERANGE;
+
+        xsprintf(ln, USEC_FMT "\n", n);
+
+        return write_string_file(fn, ln, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
+}
+
+int read_timestamp_file(const char *fn, usec_t *ret) {
+        _cleanup_free_ char *ln = NULL;
+        uint64_t t;
+        int r;
+
+        r = read_one_line_file(fn, &ln);
+        if (r < 0)
+                return r;
+
+        r = safe_atou64(ln, &t);
+        if (r < 0)
+                return r;
+
+        if (t <= 0 || t >= (uint64_t) USEC_INFINITY)
+                return -ERANGE;
+
+        *ret = (usec_t) t;
+        return 0;
+}
+
+int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space) {
+        int r;
+
+        assert(s);
+
+        /* Outputs the specified string with fputs(), but optionally prefixes it with a separator. The *space parameter
+         * when specified shall initially point to a boolean variable initialized to false. It is set to true after the
+         * first invocation. This call is supposed to be use in loops, where a separator shall be inserted between each
+         * element, but not before the first one. */
+
+        if (!f)
+                f = stdout;
+
+        if (space) {
+                if (!separator)
+                        separator = " ";
+
+                if (*space) {
+                        r = fputs(separator, f);
+                        if (r < 0)
+                                return r;
+                }
+
+                *space = true;
+        }
+
+        return fputs(s, f);
+}