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tmpfiles: support writing short strings to files, in order to support /sys manipulations at boot time, a la sysctl

This commit is contained in:
Lennart Poettering 2012-01-18 16:39:04 +01:00
parent 88f0664562
commit 31ed59c511
4 changed files with 77 additions and 13 deletions
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3
TODO
View File

@ -21,6 +21,8 @@ Bugfixes:
Features:
* rework namespace support, don't use pivot_root, and mount things after creating the namespace, not before
* systemctl journal command
* journalctl: --cursor support, priority filtering
@ -82,7 +84,6 @@ Features:
* service restart retry configuration
* tmpfiles: apply "x" on "D" too (see patch from William Douglas)
* tmpfiles: support generation of char/block devices, symlinks and one-line files (think sysfs)
* don't set $HOME in services unless requested

14
man/tmpfiles.d.xml
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@ -98,12 +98,17 @@ L /tmp/foobar - - - - /dev/null</programlisting>
<variablelist>
<varlistentry>
<term><varname>f</varname></term>
<listitem><para>Create a file if it doesn't exist yet</para></listitem>
<listitem><para>Create a file if it doesn't exist yet (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>F</varname></term>
<listitem><para>Create or truncate a file</para></listitem>
<listitem><para>Create or truncate a file (optionally writing a short string into it, if the argument parameter is passed)</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>w</varname></term>
<listitem><para>Write the argument parameter to a file, if it exists.</para></listitem>
</varlistentry>
<varlistentry>
@ -260,7 +265,10 @@ L /tmp/foobar - - - - /dev/null</programlisting>
path of the symlink. For c, b determines the
major/minor of the device node, with major and
minor formatted as integers, separated by :,
e.g. "1:3". Ignored for all other lines.</para>
e.g. "1:3". For f, F, w may be used to specify
a short string that is written to the file,
suffixed by a newline. Ignored for all other
lines.</para>
</refsect2>
</refsect1>

70
src/tmpfiles.c
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@ -54,6 +54,7 @@ typedef enum ItemType {
/* These ones take file names */
CREATE_FILE = 'f',
TRUNCATE_FILE = 'F',
WRITE_FILE = 'w',
CREATE_DIRECTORY = 'd',
TRUNCATE_DIRECTORY = 'D',
CREATE_FIFO = 'p',
@ -574,19 +575,48 @@ static int create_item(Item *i) {
return 0;
case CREATE_FILE:
case TRUNCATE_FILE: {
int fd;
case TRUNCATE_FILE:
case WRITE_FILE: {
int fd, flags;
flags = i->type == CREATE_FILE ? O_CREAT|O_APPEND :
i->type == TRUNCATE_FILE ? O_CREAT|O_TRUNC : 0;
u = umask(0);
fd = open(i->path, O_CREAT|O_NDELAY|O_CLOEXEC|O_WRONLY|O_NOCTTY|O_NOFOLLOW|
(i->type == TRUNCATE_FILE ? O_TRUNC : 0), i->mode);
fd = open(i->path, flags|O_NDELAY|O_CLOEXEC|O_WRONLY|O_NOCTTY|O_NOFOLLOW, i->mode);
umask(u);
if (fd < 0) {
if (i->type == WRITE_FILE && errno == ENOENT)
break;
log_error("Failed to create file %s: %m", i->path);
return -errno;
}
if (i->argument) {
ssize_t n;
size_t l;
struct iovec iovec[2];
static const char new_line = '\n';
l = strlen(i->argument);
zero(iovec);
iovec[0].iov_base = i->argument;
iovec[0].iov_len = l;
iovec[1].iov_base = (void*) &new_line;
iovec[1].iov_len = 1;
n = writev(fd, iovec, 2);
if (n < 0 || (size_t) n != l+1) {
log_error("Failed to write file %s: %s", i->path, n < 0 ? strerror(-n) : "Short");
close_nointr_nofail(fd);
return n < 0 ? n : -EIO;
}
}
close_nointr_nofail(fd);
if (stat(i->path, &st) < 0) {
@ -752,6 +782,7 @@ static int remove_item_instance(Item *i, const char *instance) {
case IGNORE_PATH:
case RELABEL_PATH:
case RECURSIVE_RELABEL_PATH:
case WRITE_FILE:
break;
case REMOVE_PATH:
@ -793,6 +824,7 @@ static int remove_item(Item *i) {
case IGNORE_PATH:
case RELABEL_PATH:
case RECURSIVE_RELABEL_PATH:
case WRITE_FILE:
break;
case REMOVE_PATH:
@ -857,7 +889,10 @@ static bool item_equal(Item *a, Item *b) {
(a->age_set && a->age != b->age))
return false;
if (a->type == CREATE_SYMLINK &&
if ((a->type == CREATE_FILE ||
a->type == TRUNCATE_FILE ||
a->type == WRITE_FILE ||
a->type == CREATE_SYMLINK) &&
!streq(a->argument, b->argument))
return false;
@ -874,7 +909,7 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
char *mode = NULL, *user = NULL, *group = NULL, *age = NULL;
char type;
Hashmap *h;
int r;
int r, n = -1;
assert(fname);
assert(line >= 1);
@ -893,19 +928,30 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
"%ms "
"%ms "
"%ms "
"%ms",
"%n",
&type,
&i->path,
&mode,
&user,
&group,
&age,
&i->argument) < 2) {
&n) < 2) {
log_error("[%s:%u] Syntax error.", fname, line);
r = -EIO;
goto finish;
}
if (n >= 0) {
n += strspn(buffer+n, WHITESPACE);
if (buffer[n] != 0 && (buffer[n] != '-' || buffer[n+1] != 0)) {
i->argument = unquote(buffer+n, "\"");
if (!i->argument) {
log_error("Out of memory");
return -ENOMEM;
}
}
}
switch(type) {
case CREATE_FILE:
@ -928,6 +974,14 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
}
break;
case WRITE_FILE:
if (!i->argument) {
log_error("[%s:%u] Write file requires argument.", fname, line);
r = -EBADMSG;
goto finish;
}
break;
case CREATE_CHAR_DEVICE:
case CREATE_BLOCK_DEVICE: {
unsigned major, minor;

3
src/util.c
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@ -4118,7 +4118,8 @@ char *unquote(const char *s, const char* quotes) {
size_t l;
assert(s);
if ((l = strlen(s)) < 2)
l = strlen(s);
if (l < 2)
return strdup(s);
if (strchr(quotes, s[0]) && s[l-1] == s[0])