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-rw-r--r--src/hostnamed.c2
-rw-r--r--src/shutdownd.c2
-rw-r--r--src/user-sessions.c2
-rw-r--r--src/util.c247
-rw-r--r--src/util.h29
5 files changed, 260 insertions, 22 deletions
diff --git a/src/hostnamed.c b/src/hostnamed.c
index cf2172fd2c..68c5715b0e 100644
--- a/src/hostnamed.c
+++ b/src/hostnamed.c
@@ -201,7 +201,7 @@ static int write_data_static_hostname(void) {
return 0;
}
- return write_one_line_file("/etc/hostname", data[PROP_STATIC_HOSTNAME]);
+ return write_one_line_file_atomic("/etc/hostname", data[PROP_STATIC_HOSTNAME]);
}
static int write_data_other(void) {
diff --git a/src/shutdownd.c b/src/shutdownd.c
index 8f765b4517..13819417c3 100644
--- a/src/shutdownd.c
+++ b/src/shutdownd.c
@@ -320,7 +320,7 @@ int main(int argc, char *argv[]) {
log_info("Creating /run/nologin, blocking further logins...");
- if ((e = write_one_line_file("/run/nologin", "System is going down.")) < 0)
+ if ((e = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0)
log_error("Failed to create /run/nologin: %s", strerror(-e));
else
unlink_nologin = true;
diff --git a/src/user-sessions.c b/src/user-sessions.c
index e045b88c10..ffb8657436 100644
--- a/src/user-sessions.c
+++ b/src/user-sessions.c
@@ -67,7 +67,7 @@ int main(int argc, char*argv[]) {
int r, q;
char *cgroup_user_tree = NULL;
- if ((r = write_one_line_file("/run/nologin", "System is going down.")) < 0)
+ if ((r = write_one_line_file_atomic("/run/nologin", "System is going down.")) < 0)
log_error("Failed to create /run/nologin: %s", strerror(-r));
if ((q = cg_get_user_path(&cgroup_user_tree)) < 0) {
diff --git a/src/util.c b/src/util.c
index 81d247ca46..dfb153bbb6 100644
--- a/src/util.c
+++ b/src/util.c
@@ -567,6 +567,7 @@ int write_one_line_file(const char *fn, const char *line) {
if (!(f = fopen(fn, "we")))
return -errno;
+ errno = 0;
if (fputs(line, f) < 0) {
r = -errno;
goto finish;
@@ -590,6 +591,64 @@ finish:
return r;
}
+int fchmod_umask(int fd, mode_t m) {
+ mode_t u;
+ int r;
+
+ u = umask(0777);
+ r = fchmod(fd, m & (~u)) < 0 ? -errno : 0;
+ umask(u);
+
+ return r;
+}
+
+int write_one_line_file_atomic(const char *fn, const char *line) {
+ FILE *f;
+ int r;
+ char *p;
+
+ 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)) {
+ if (errno != 0)
+ r = -errno;
+ else
+ r = -EIO;
+ } else {
+ if (rename(p, fn) < 0)
+ r = -errno;
+ else
+ r = 0;
+ }
+
+finish:
+ if (r < 0)
+ unlink(p);
+
+ fclose(f);
+ free(p);
+
+ return r;
+}
+
int read_one_line_file(const char *fn, char **line) {
FILE *f;
int r;
@@ -621,7 +680,7 @@ finish:
return r;
}
-int read_full_file(const char *fn, char **contents) {
+int read_full_file(const char *fn, char **contents, size_t *size) {
FILE *f;
int r;
size_t n, l;
@@ -636,6 +695,12 @@ int read_full_file(const char *fn, char **contents) {
goto finish;
}
+ /* Safety check */
+ if (st.st_size > 4*1024*1024) {
+ r = -E2BIG;
+ goto finish;
+ }
+
n = st.st_size > 0 ? st.st_size : LINE_MAX;
l = 0;
@@ -680,6 +745,9 @@ int read_full_file(const char *fn, char **contents) {
*contents = buf;
buf = NULL;
+ if (size)
+ *size = l;
+
r = 0;
finish:
@@ -699,7 +767,7 @@ int parse_env_file(
assert(fname);
assert(separator);
- if ((r = read_full_file(fname, &contents)) < 0)
+ if ((r = read_full_file(fname, &contents, NULL)) < 0)
return r;
p = contents;
@@ -838,15 +906,17 @@ finish:
}
int write_env_file(const char *fname, char **l) {
-
- char **i;
+ char **i, *p;
FILE *f;
int r;
- f = fopen(fname, "we");
- if (!f)
- return -errno;
+ 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);
@@ -854,8 +924,23 @@ int write_env_file(const char *fname, char **l) {
fflush(f);
- r = ferror(f) ? -errno : 0;
+ 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;
}
@@ -4778,6 +4863,152 @@ int hwclock_set_time(const struct tm *tm) {
return err;
}
+int copy_file(const char *from, const char *to) {
+ int r, fdf, fdt;
+
+ assert(from);
+ assert(to);
+
+ fdf = open(from, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (fdf < 0)
+ return -errno;
+
+ fdt = open(to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY, 0644);
+ if (fdt < 0) {
+ close_nointr_nofail(fdf);
+ return -errno;
+ }
+
+ for (;;) {
+ char buf[PIPE_BUF];
+ ssize_t n, k;
+
+ n = read(fdf, buf, sizeof(buf));
+ if (n < 0) {
+ r = -errno;
+
+ close_nointr_nofail(fdf);
+ close_nointr(fdt);
+ unlink(to);
+
+ return r;
+ }
+
+ if (n == 0)
+ break;
+
+ errno = 0;
+ k = loop_write(fdt, buf, n, false);
+ if (n != k) {
+ r = k < 0 ? k : (errno ? -errno : -EIO);
+
+ close_nointr_nofail(fdf);
+ close_nointr(fdt);
+
+ unlink(to);
+ return r;
+ }
+ }
+
+ close_nointr_nofail(fdf);
+ r = close_nointr(fdt);
+
+ if (r < 0) {
+ unlink(to);
+ return r;
+ }
+
+ return 0;
+}
+
+int symlink_or_copy(const char *from, const char *to) {
+ char *pf = NULL, *pt = NULL;
+ struct stat a, b;
+ int r;
+
+ assert(from);
+ assert(to);
+
+ if (parent_of_path(from, &pf) < 0 ||
+ parent_of_path(to, &pt) < 0) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (stat(pf, &a) < 0 ||
+ stat(pt, &b) < 0) {
+ r = -errno;
+ goto finish;
+ }
+
+ if (a.st_dev != b.st_dev) {
+ free(pf);
+ free(pt);
+
+ return copy_file(from, to);
+ }
+
+ if (symlink(from, to) < 0) {
+ r = -errno;
+ goto finish;
+ }
+
+ r = 0;
+
+finish:
+ free(pf);
+ free(pt);
+
+ return r;
+}
+
+int symlink_or_copy_atomic(const char *from, const char *to) {
+ char *t, *x;
+ const char *fn;
+ size_t k;
+ unsigned long long ull;
+ unsigned i;
+ int r;
+
+ assert(from);
+ assert(to);
+
+ t = new(char, strlen(to) + 1 + 16 + 1);
+ if (!t)
+ return -ENOMEM;
+
+ fn = file_name_from_path(to);
+ k = fn-to;
+ memcpy(t, to, k);
+ t[k] = '.';
+ x = stpcpy(t+k+1, fn);
+
+ ull = random_ull();
+ for (i = 0; i < 16; i++) {
+ *(x++) = hexchar(ull & 0xF);
+ ull >>= 4;
+ }
+
+ *x = 0;
+
+ r = symlink_or_copy(from, t);
+ if (r < 0) {
+ unlink(t);
+ free(t);
+ return r;
+ }
+
+ if (rename(t, to) < 0) {
+ r = -errno;
+ unlink(t);
+ free(t);
+ return r;
+ }
+
+ free(t);
+ return r;
+}
+
static const char *const ioprio_class_table[] = {
[IOPRIO_CLASS_NONE] = "none",
[IOPRIO_CLASS_RT] = "realtime",
diff --git a/src/util.h b/src/util.h
index 15dfe17d3b..bd98b654fd 100644
--- a/src/util.h
+++ b/src/util.h
@@ -200,8 +200,9 @@ pid_t get_parent_of_pid(pid_t pid, pid_t *ppid);
int get_starttime_of_pid(pid_t pid, unsigned long long *st);
int write_one_line_file(const char *fn, const char *line);
+int write_one_line_file_atomic(const char *fn, const char *line);
int read_one_line_file(const char *fn, char **line);
-int read_full_file(const char *fn, char **contents);
+int read_full_file(const char *fn, char **contents, size_t *size);
int parse_env_file(const char *fname, const char *separator, ...) _sentinel_;
int load_env_file(const char *fname, char ***l);
@@ -422,6 +423,22 @@ int terminal_vhangup(const char *name);
int vt_disallocate(const char *name);
+int copy_file(const char *from, const char *to);
+int symlink_or_copy(const char *from, const char *to);
+int symlink_or_copy_atomic(const char *from, const char *to);
+
+int fchmod_umask(int fd, mode_t mode);
+
+int conf_files_list(char ***strv, const char *suffix, const char *dir, ...);
+
+bool hwclock_is_localtime(void);
+
+int hwclock_apply_localtime_delta(void);
+
+int hwclock_get_time(struct tm *tm);
+
+int hwclock_set_time(const struct tm *tm);
+
#define NULSTR_FOREACH(i, l) \
for ((i) = (l); (i) && *(i); (i) = strchr((i), 0)+1)
@@ -454,14 +471,4 @@ int signal_from_string(const char *s);
int signal_from_string_try_harder(const char *s);
-int conf_files_list(char ***strv, const char *suffix, const char *dir, ...);
-
-bool hwclock_is_localtime(void);
-
-int hwclock_apply_localtime_delta(void);
-
-int hwclock_get_time(struct tm *tm);
-
-int hwclock_set_time(const struct tm *tm);
-
#endif