[systemd-devel] [RFC][PATCH 1/2] fstab-generator: generate new_root.mount in initrd
Tom Gundersen
teg at jklm.no
Tue Nov 27 16:30:17 PST 2012
The configuration is taken from /proc/cmdline, aiming at emulating the
behavior of the kernel when no initramfs is used.
The supported options are: root=, rootfstype=, rootwait=, rootflags=,
ro, and rw. rootdelay= was dropped, as it is not really useful in a
systemd world, but could easily be added.
Cc: Harald Hoyer <harald at redhat.com>
Cc: Dave Reisner <dreisner at archlinux.org>
---
Hi guys,
Together with the next patch this aims to add enough kernel commandline parsing support
to systemd so that it can be used in an initramfs without any extra glue to parse the
command line and pass on the correct parameters to systemd.
A patch exists using this work to add (shell-free) systemd support to Arch's mkinitcpio [0].
This is based on similar work in dracut.
Comments welcome,
Tom
[0]: <https://mailman.archlinux.org/pipermail/arch-projects/2012-November/003446.html>
src/fstab-generator/fstab-generator.c | 159 +++++++++++++++++++++++++++++-----
1 file changed, 135 insertions(+), 24 deletions(-)
diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
index ba55f2c..8b0b548 100644
--- a/src/fstab-generator/fstab-generator.c
+++ b/src/fstab-generator/fstab-generator.c
@@ -202,18 +202,21 @@ static bool mount_is_network(struct mntent *me) {
fstype_is_network(me->mnt_type);
}
-static int add_mount(const char *what, const char *where, struct mntent *me) {
+static int add_mount(const char *what, const char *where, const char *type, const char *opts,
+ int passno, bool wait, bool noauto, bool nofail, bool automount, bool isbind, bool isnetwork,
+ const char *source) {
char *name = NULL, *unit = NULL, *lnk = NULL, *device = NULL, *automount_name = NULL, *automount_unit = NULL;
FILE *f = NULL;
- bool noauto, nofail, automount, isbind, isnetwork;
int r;
const char *post, *pre;
assert(what);
assert(where);
- assert(me);
+ assert(type);
+ assert(opts);
+ assert(source);
- if (streq(me->mnt_type, "autofs"))
+ if (streq(type, "autofs"))
return 0;
if (!is_path(where)) {
@@ -225,15 +228,6 @@ static int add_mount(const char *what, const char *where, struct mntent *me) {
mount_point_ignore(where))
return 0;
- isnetwork = mount_is_network(me);
- isbind = !!hasmntopt(me, "bind");
-
- noauto = !!hasmntopt(me, "noauto");
- nofail = !!hasmntopt(me, "nofail");
- automount =
- hasmntopt(me, "comment=systemd.automount") ||
- hasmntopt(me, "x-systemd.automount");
-
if (isnetwork) {
post = SPECIAL_REMOTE_FS_TARGET;
pre = SPECIAL_REMOTE_FS_PRE_TARGET;
@@ -264,10 +258,12 @@ static int add_mount(const char *what, const char *where, struct mntent *me) {
goto finish;
}
- fputs("# Automatically generated by systemd-fstab-generator\n\n"
+ fprintf(f,
+ "# Automatically generated by systemd-fstab-generator\n\n"
"[Unit]\n"
- "SourcePath=/etc/fstab\n"
- "DefaultDependencies=no\n", f);
+ "SourcePath=%s\n"
+ "DefaultDependencies=no\n",
+ source);
if (!path_equal(where, "/"))
fprintf(f,
@@ -293,14 +289,18 @@ static int add_mount(const char *what, const char *where, struct mntent *me) {
"FsckPassNo=%i\n",
what,
where,
- me->mnt_type,
- me->mnt_passno);
+ type,
+ passno);
- if (!isempty(me->mnt_opts) &&
- !streq(me->mnt_opts, "defaults"))
+ if (!isempty(opts) &&
+ !streq(opts, "defaults"))
fprintf(f,
"Options=%s\n",
- me->mnt_opts);
+ opts);
+
+ if (wait)
+ fprintf(f,
+ "TimeoutSec=0\n");
fflush(f);
if (ferror(f)) {
@@ -459,7 +459,13 @@ static int parse_fstab(void) {
if (streq(me->mnt_type, "swap"))
k = add_swap(what, me);
else
- k = add_mount(what, where, me);
+ k = add_mount(what, where, me->mnt_type, me->mnt_opts,
+ me->mnt_passno, false, !!hasmntopt(me, "noauto"),
+ !!hasmntopt(me, "nofail"),
+ hasmntopt(me, "comment=systemd.automount") ||
+ hasmntopt(me, "x-systemd.automount"),
+ !!hasmntopt(me, "bind"), mount_is_network(me),
+ "/etc/fstab");
free(what);
free(where);
@@ -473,6 +479,108 @@ finish:
return r;
}
+static int parse_new_root_from_proc_cmdline(void) {
+ char *line = NULL, *w, *state, *what = NULL, *type = NULL, *opts = NULL;
+ int r, k;
+ size_t l;
+ bool wait = false;
+
+ r = read_one_line_file("/proc/cmdline", &line);
+ if (r < 0) {
+ log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
+ return 0;
+ }
+
+ opts = strdup("defaults");
+ if (!opts) {
+ r = log_oom();
+ goto finish;
+ }
+ type = strdup("auto");
+ if (!type) {
+ r = log_oom();
+ goto finish;
+ }
+
+ /* root= and roofstype= may occur more than once, the last instance should take precedence.
+ * In the case of multiple rootflags= the arguments should be concatenated */
+ FOREACH_WORD_QUOTED(w, l, line, state) {
+ char *word, *tmp_word;
+
+ word = strndup(w, l);
+ if (!word) {
+ r = log_oom();
+ goto finish;
+ }
+
+ if (startswith(word, "#")) {
+ break;
+
+ } else if (startswith(word, "root=")) {
+ if (what) {
+ free(what);
+ }
+ what = fstab_node_to_udev_node(word+5);
+ if (!what) {
+ r = log_oom();
+ goto finish;
+ }
+
+ } else if (startswith(word, "rootfstype=")) {
+ if (type)
+ free(type);
+ type = strdup(word + 11);
+ if (!type) {
+ r = log_oom();
+ goto finish;
+ }
+
+ } else if (startswith(word, "rootflags=")) {
+ tmp_word = opts;
+ opts = strjoin(opts, ",", word + 10, NULL);
+ free(tmp_word);
+ if (!opts) {
+ r = log_oom();
+ goto finish;
+ }
+
+ } else if (streq(word, "ro") || streq(word, "rw")) {
+ tmp_word = opts;
+ opts = strjoin(opts, ",", word, NULL);
+ free(tmp_word);
+ if (!opts) {
+ r = log_oom();
+ goto finish;
+ }
+
+ } else if (streq(word, "rootwait")) {
+ wait = true;
+ }
+
+ free(word);
+ }
+
+ if (what) {
+
+ log_debug("Found entry what=%s where=/new_root type=%s", what, type);
+ k = add_mount(what, "/new_root", type, opts, 0, wait, false, false,
+ false, false, false, "/proc/cmdline");
+ if (k < 0)
+ r = k;
+ }
+
+finish:
+ if(what)
+ free(what);
+ if(type)
+ free(type);
+ if(opts)
+ free(opts);
+ if(line)
+ free(line);
+ return r;
+}
+
static int parse_proc_cmdline(void) {
char *line, *w, *state;
int r;
@@ -530,7 +638,7 @@ finish:
}
int main(int argc, char *argv[]) {
- int r;
+ int r, k = 0;
if (argc > 1 && argc != 4) {
log_error("This program takes three or no arguments.");
@@ -549,10 +657,13 @@ int main(int argc, char *argv[]) {
if (parse_proc_cmdline() < 0)
return EXIT_FAILURE;
+ if (in_initrd())
+ k = parse_new_root_from_proc_cmdline();
+
if (!arg_enabled)
return EXIT_SUCCESS;
r = parse_fstab();
- return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+ return (r < 0) || (k < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
}
--
1.8.0.1
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