From 768100efd57ffbbefe9beaa33d1dd5ecc7f69173 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 3 Apr 2013 19:56:39 +0200
Subject: [PATCH] fileio: write proper env var write-out code

This will properly escape all weird chars when writing env var files.
With this in place we can now read and write environment files where the
values contain arbitrary weird chars.

This enables hostnamed and suchlike to finally properly save pretty host
names with backlashes or quotes in them.
---
 src/shared/fileio.c    | 37 +++++++++++++++++++++++++++++++++----
 src/test/test-fileio.c | 27 +++++++++++++++++++++++++--
 2 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/src/shared/fileio.c b/src/shared/fileio.c
index 96e23c5bbb6..2ccb9e7edc7 100644
--- a/src/shared/fileio.c
+++ b/src/shared/fileio.c
@@ -522,6 +522,37 @@ int load_env_file(const char *fname, const char *newline, char ***rl) {
         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) || chars_intersect(p, WHITESPACE "\'\"\\")) {
+                fputc('\"', f);
+
+                for (; *p; p++) {
+                        if (strchr("\'\"\\", *p))
+                                fputc('\\', f);
+
+                        fputc(*p, f);
+                }
+
+                fputc('\"', f);
+        } else
+                fputs(p, f);
+
+        fputc('\n', f);
+}
+
 int write_env_file(const char *fname, char **l) {
         char **i;
         char _cleanup_free_ *p = NULL;
@@ -535,10 +566,8 @@ int write_env_file(const char *fname, char **l) {
         fchmod_umask(fileno(f), 0644);
 
         errno = 0;
-        STRV_FOREACH(i, l) {
-                fputs(*i, f);
-                fputc('\n', f);
-        }
+        STRV_FOREACH(i, l)
+                write_env_var(f, *i);
 
         fflush(f);
 
diff --git a/src/test/test-fileio.c b/src/test/test-fileio.c
index 55eb7539fd8..7adf2efdd1b 100644
--- a/src/test/test-fileio.c
+++ b/src/test/test-fileio.c
@@ -32,8 +32,9 @@ static void test_parse_env_file(void) {
         int fd, r;
         FILE *f;
         _cleanup_free_ char *one = NULL, *two = NULL, *three = NULL, *four = NULL, *five = NULL, *six = NULL, *seven = NULL;
-        _cleanup_strv_free_ char **a = NULL;
+        _cleanup_strv_free_ char **a = NULL, **b = NULL;
         char **i;
+        unsigned k;
 
         fd = mkostemp(t, O_CLOEXEC);
         assert_se(fd >= 0);
@@ -90,9 +91,31 @@ static void test_parse_env_file(void) {
         assert_se(r >= 0);
 
         STRV_FOREACH(i, a)
-                log_info("Got: %s", *i);
+                log_info("Got: <%s>", *i);
+
+        assert_se(streq(a[0], "one=BAR"));
+        assert_se(streq(a[1], "two=bar"));
+        assert_se(streq(a[2], "three=333\nxxxx"));
+        assert_se(streq(a[3], "four=44\"44"));
+        assert_se(streq(a[4], "five=55\'55FIVEcinco"));
+        assert_se(streq(a[5], "six=seis sechs sis"));
+        assert_se(streq(a[6], "seven="));
+        assert_se(a[7] == NULL);
+
+        r = write_env_file("/tmp/test-fileio", a);
+        assert_se(r >= 0);
+
+        r = load_env_file("/tmp/test-fileio", NULL, &b);
+        assert_se(r >= 0);
+
+        k = 0;
+        STRV_FOREACH(i, b) {
+                log_info("Got2: <%s>", *i);
+                assert_se(streq(*i, a[k++]));
+        }
 
         unlink(t);
+        unlink("/tmp/test-fileio");
 }
 
 int main(int argc, char *argv[]) {