honor SELinux labels, when creating and writing config files

Also split out some fileio functions to fileio.c and provide a SELinux
aware pendant in fileio-label.c

see https://bugzilla.redhat.com/show_bug.cgi?id=881577

1 files changed, 383 insertions, 0 deletions

diff --git a/src/shared/fileio.c b/src/shared/fileio.c
new file mode 100644
index 0000000000..4e6ff16045
--- /dev/null
+++ b/src/shared/fileio.c
@@ -0,0 +1,383 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  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 <unistd.h>
+#include "fileio.h"
+#include "util.h"
+#include "strv.h"
+
+int write_one_line_file(const char *fn, const char *line) {
+        _cleanup_fclose_ FILE *f = NULL;
+
+        assert(fn);
+        assert(line);
+
+        f = fopen(fn, "we");
+        if (!f)
+                return -errno;
+
+        errno = 0;
+        if (fputs(line, f) < 0)
+                return errno ? -errno : -EIO;
+
+        if (!endswith(line, "\n"))
+                fputc('\n', f);
+
+        fflush(f);
+
+        if (ferror(f))
+                return errno ? -errno : -EIO;
+
+        return 0;
+}
+
+int write_one_line_file_atomic(const char *fn, const char *line) {
+        _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;
+
+        fchmod_umask(fileno(f), 0644);
+
+        errno = 0;
+        if (fputs(line, f) < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!endswith(line, "\n"))
+                fputc('\n', f);
+
+        fflush(f);
+
+        if (ferror(f))
+                r = errno ? -errno : -EIO;
+        else {
+                if (rename(p, fn) < 0)
+                        r = -errno;
+                else
+                        r = 0;
+        }
+
+finish:
+        if (r < 0)
+                unlink(p);
+
+        return r;
+}
+
+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 ? -errno : -EIO;
+
+                t[0] = 0;
+        }
+
+        c = strdup(t);
+        if (!c)
+                return -ENOMEM;
+        truncate_nl(c);
+
+        *line = c;
+        return 0;
+}
+
+int read_full_file(const char *fn, char **contents, size_t *size) {
+        _cleanup_fclose_ FILE *f = NULL;
+        size_t n, l;
+        _cleanup_free_ char *buf = NULL;
+        struct stat st;
+
+        assert(fn);
+        assert(contents);
+
+        f = fopen(fn, "re");
+        if (!f)
+                return -errno;
+
+        if (fstat(fileno(f), &st) < 0)
+                return -errno;
+
+        /* Safety check */
+        if (st.st_size > 4*1024*1024)
+                return -E2BIG;
+
+        n = st.st_size > 0 ? st.st_size : LINE_MAX;
+        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;
+
+        if (size)
+                *size = l;
+
+        return 0;
+}
+
+int parse_env_file(
+                const char *fname,
+                const char *separator, ...) {
+
+        int r = 0;
+        char *contents = NULL, *p;
+
+        assert(fname);
+        assert(separator);
+
+        if ((r = read_full_file(fname, &contents, NULL)) < 0)
+                return r;
+
+        p = contents;
+        for (;;) {
+                const char *key = NULL;
+
+                p += strspn(p, separator);
+                p += strspn(p, WHITESPACE);
+
+                if (!*p)
+                        break;
+
+                if (!strchr(COMMENTS, *p)) {
+                        va_list ap;
+                        char **value;
+
+                        va_start(ap, separator);
+                        while ((key = va_arg(ap, char *))) {
+                                size_t n;
+                                char *v;
+
+                                value = va_arg(ap, char **);
+
+                                n = strlen(key);
+                                if (!strneq(p, key, n) ||
+                                    p[n] != '=')
+                                        continue;
+
+                                p += n + 1;
+                                n = strcspn(p, separator);
+
+                                if (n >= 2 &&
+                                    strchr(QUOTES, p[0]) &&
+                                    p[n-1] == p[0])
+                                        v = strndup(p+1, n-2);
+                                else
+                                        v = strndup(p, n);
+
+                                if (!v) {
+                                        r = -ENOMEM;
+                                        va_end(ap);
+                                        goto fail;
+                                }
+
+                                if (v[0] == '\0') {
+                                        /* return empty value strings as NULL */
+                                        free(v);
+                                        v = NULL;
+                                }
+
+                                free(*value);
+                                *value = v;
+
+                                p += n;
+
+                                r ++;
+                                break;
+                        }
+                        va_end(ap);
+                }
+
+                if (!key)
+                        p += strcspn(p, separator);
+        }
+
+fail:
+        free(contents);
+        return r;
+}
+
+int load_env_file(const char *fname, char ***rl) {
+
+        _cleanup_fclose_ FILE *f;
+        _cleanup_strv_free_ char **m = NULL;
+        _cleanup_free_ char *c = NULL;
+
+        assert(fname);
+        assert(rl);
+
+        /* This reads an environment file, but will not complain about
+         * any invalid assignments, that needs to be done by the
+         * caller */
+
+        f = fopen(fname, "re");
+        if (!f)
+                return -errno;
+
+        while (!feof(f)) {
+                char l[LINE_MAX], *p, *cs, *b;
+
+                if (!fgets(l, sizeof(l), f)) {
+                        if (ferror(f))
+                                return -errno;
+
+                        /* The previous line was a continuation line?
+                         * Let's process it now, before we leave the
+                         * loop */
+                        if (c)
+                                goto process;
+
+                        break;
+                }
+
+                /* Is this a continuation line? If so, just append
+                 * this to c, and go to next line right-away */
+                cs = endswith(l, "\\\n");
+                if (cs) {
+                        *cs = '\0';
+                        b = strappend(c, l);
+                        if (!b)
+                                return -ENOMEM;
+
+                        free(c);
+                        c = b;
+                        continue;
+                }
+
+                /* If the previous line was a continuation line,
+                 * append the current line to it */
+                if (c) {
+                        b = strappend(c, l);
+                        if (!b)
+                                return -ENOMEM;
+
+                        free(c);
+                        c = b;
+                }
+
+        process:
+                p = strstrip(c ? c : l);
+
+                if (*p && !strchr(COMMENTS, *p)) {
+                        _cleanup_free_ char *u;
+                        int k;
+
+                        u = normalize_env_assignment(p);
+                        if (!u)
+                                return -ENOMEM;
+
+                        k = strv_extend(&m, u);
+                        if (k < 0)
+                                return -ENOMEM;
+                }
+
+                free(c);
+                c = NULL;
+        }
+
+        *rl = m;
+        m = NULL;
+
+        return 0;
+}
+
+int write_env_file(const char *fname, char **l) {
+        char **i, *p;
+        FILE *f;
+        int r;
+
+        r = fopen_temporary(fname, &f, &p);
+        if (r < 0)
+                return r;
+
+        fchmod_umask(fileno(f), 0644);
+
+        errno = 0;
+        STRV_FOREACH(i, l) {
+                fputs(*i, f);
+                fputc('\n', f);
+        }
+
+        fflush(f);
+
+        if (ferror(f)) {
+                if (errno != 0)
+                        r = -errno;
+                else
+                        r = -EIO;
+        } else {
+                if (rename(p, fname) < 0)
+                        r = -errno;
+                else
+                        r = 0;
+        }
+
+        if (r < 0)
+                unlink(p);
+
+        fclose(f);
+        free(p);
+
+        return r;
+}