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tmpfiles: add support for creating symlinks, char/block device nodes

This commit is contained in:
Lennart Poettering 2012-01-17 15:04:12 +01:00
parent fc3c1c6e09
commit 468d726bdd
2 changed files with 176 additions and 31 deletions
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76
man/tmpfiles.d.xml
View File

@ -67,27 +67,31 @@
<title>Configuration Format</title>
<para>Each configuration file is named in the style of
<filename>&lt;program&gt;.conf</filename>.
Files in <filename>/etc/</filename> overwrite
files with the same name in <filename>/usr/lib/</filename>.
Files in <filename>/run</filename> overwrite files with
the same name in <filename>/etc/</filename> and
<filename>/usr/lib/</filename>. Packages should install their
configuration files in <filename>/usr/lib/</filename>, files
in <filename>/etc/</filename> are reserved for the local
administration, which possibly decides to overwrite the
configurations installed from packages. All files are sorted
by filename in alphabetical order, regardless in which of the
directories they reside, to ensure that a specific
configuration file takes precedence over another file with
an alphabetically later name.</para>
<filename>&lt;program&gt;.conf</filename>. Files in
<filename>/etc/</filename> override files with the
same name in <filename>/usr/lib/</filename>. Files in
<filename>/run</filename> override files with the same
name in <filename>/etc/</filename> and
<filename>/usr/lib/</filename>. Packages should
install their configuration files in
<filename>/usr/lib/</filename>, files in
<filename>/etc/</filename> are reserved for the local
administrator, who may choose to override the
configurations installed from packages. The list of
configuration files are sorted by their filename in
alphabetical order, regardless in which of the
directories they reside, to guarantee that a
configuration file takes precedence over another
configuration file with an alphabetically later
name.</para>
<para>The configuration format is one line per path
containing action, mode, ownership and age
containing action, path, mode, ownership, age and argument
fields:</para>
<programlisting>Type Path Mode UID GID Age
d /run/user 0755 root root 10d</programlisting>
<programlisting>Type Path Mode UID GID Age Argument
d /run/user 0755 root root 10d -
L /tmp/foobar - - - - /dev/null</programlisting>
<refsect2>
<title>Type</title>
@ -117,6 +121,21 @@ d /run/user 0755 root root 10d</programlisting>
<listitem><para>Create a named pipe (FIFO) if it doesn't exist yet</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>L</varname></term>
<listitem><para>Create a symlink if it doesn't exist yet</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>c</varname></term>
<listitem><para>Create a character device node if it doesn't exist yet</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>b</varname></term>
<listitem><para>Create a block device node if it doesn't exist yet</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>x</varname></term>
<listitem><para>Ignore a path
@ -185,10 +204,11 @@ d /run/user 0755 root root 10d</programlisting>
<para>The file access mode to use when
creating this file or directory. If omitted or
when set to - the default is used: 0755 for
directories, 0644 for files. For z, Z lines
if omitted or when set to - the file access mode will
not be modified. This parameter is ignored for x, r, R
lines.</para>
directories, 0644 for all other file
objects. For z, Z lines if omitted or when set
to - the file access mode will not be
modified. This parameter is ignored for x, r,
R, L lines.</para>
</refsect2>
<refsect2>
@ -200,7 +220,7 @@ d /run/user 0755 root root 10d</programlisting>
omitted or when set to - the default 0 (root)
is used. For z, Z lines when omitted or when set to -
the file ownership will not be modified.
These parameters are ignored for x, r, R lines.</para>
These parameters are ignored for x, r, R, L lines.</para>
</refsect2>
<refsect2>
@ -233,6 +253,16 @@ d /run/user 0755 root root 10d</programlisting>
is done.</para>
</refsect2>
<refsect2>
<title>Argument</title>
<para>For L lines determines the destination
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>
</refsect2>
</refsect1>
<refsect1>
@ -241,7 +271,7 @@ d /run/user 0755 root root 10d</programlisting>
<title>/etc/tmpfiles.d/screen.conf example</title>
<para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
<programlisting>d /var/run/screens 1777 root root 10d
<programlisting>d /var/run/screens 1777 root root 10d
d /var/run/uscreens 0755 root root 10d12h</programlisting>
</example>
</refsect1>

131
src/tmpfiles.c
View File

@ -57,6 +57,9 @@ typedef enum ItemType {
CREATE_DIRECTORY = 'd',
TRUNCATE_DIRECTORY = 'D',
CREATE_FIFO = 'p',
CREATE_SYMLINK = 'L',
CREATE_CHAR_DEVICE = 'c',
CREATE_BLOCK_DEVICE = 'b',
/* These ones take globs */
IGNORE_PATH = 'x',
@ -70,11 +73,14 @@ typedef struct Item {
ItemType type;
char *path;
char *argument;
uid_t uid;
gid_t gid;
mode_t mode;
usec_t age;
dev_t major_minor;
bool uid_set:1;
bool gid_set:1;
bool mode_set:1;
@ -656,6 +662,60 @@ static int create_item(Item *i) {
break;
case CREATE_SYMLINK: {
char *x;
r = symlink(i->argument, i->path);
if (r < 0 && errno != EEXIST) {
log_error("symlink(%s, %s) failed: %m", i->argument, i->path);
return -errno;
}
r = readlink_malloc(i->path, &x);
if (r < 0) {
log_error("readlink(%s) failed: %s", i->path, strerror(-r));
return -errno;
}
if (!streq(i->argument, x)) {
free(x);
log_error("%s is not the right symlinks.", i->path);
return -EEXIST;
}
free(x);
break;
}
case CREATE_BLOCK_DEVICE:
case CREATE_CHAR_DEVICE: {
u = umask(0);
r = mknod(i->path, i->mode | (i->type == CREATE_BLOCK_DEVICE ? S_IFBLK : S_IFCHR), i->major_minor);
umask(u);
if (r < 0 && errno != EEXIST) {
log_error("Failed to create device node %s: %m", i->path);
return -errno;
}
if (stat(i->path, &st) < 0) {
log_error("stat(%s) failed: %m", i->path);
return -errno;
}
if (i->type == CREATE_BLOCK_DEVICE ? !S_ISBLK(st.st_mode) : !S_ISCHR(st.st_mode)) {
log_error("%s is not a device node.", i->path);
return -EEXIST;
}
r = item_set_perms(i, i->path);
if (r < 0)
return r;
break;
}
case RELABEL_PATH:
r = glob_item(i, item_set_perms);
@ -686,6 +746,9 @@ static int remove_item_instance(Item *i, const char *instance) {
case TRUNCATE_FILE:
case CREATE_DIRECTORY:
case CREATE_FIFO:
case CREATE_SYMLINK:
case CREATE_BLOCK_DEVICE:
case CREATE_CHAR_DEVICE:
case IGNORE_PATH:
case RELABEL_PATH:
case RECURSIVE_RELABEL_PATH:
@ -701,8 +764,8 @@ static int remove_item_instance(Item *i, const char *instance) {
case TRUNCATE_DIRECTORY:
case RECURSIVE_REMOVE_PATH:
if ((r = rm_rf(instance, false, i->type == RECURSIVE_REMOVE_PATH, false)) < 0 &&
r != -ENOENT) {
r = rm_rf(instance, false, i->type == RECURSIVE_REMOVE_PATH, false);
if (r < 0 && r != -ENOENT) {
log_error("rm_rf(%s): %s", instance, strerror(-r));
return r;
}
@ -724,6 +787,9 @@ static int remove_item(Item *i) {
case TRUNCATE_FILE:
case CREATE_DIRECTORY:
case CREATE_FIFO:
case CREATE_SYMLINK:
case CREATE_CHAR_DEVICE:
case CREATE_BLOCK_DEVICE:
case IGNORE_PATH:
case RELABEL_PATH:
case RECURSIVE_RELABEL_PATH:
@ -761,6 +827,7 @@ static void item_free(Item *i) {
assert(i);
free(i->path);
free(i->argument);
free(i);
}
@ -790,6 +857,15 @@ static bool item_equal(Item *a, Item *b) {
(a->age_set && a->age != b->age))
return false;
if (a->type == CREATE_SYMLINK &&
!streq(a->argument, b->argument))
return false;
if ((a->type == CREATE_CHAR_DEVICE ||
a->type == CREATE_BLOCK_DEVICE) &&
a->major_minor != b->major_minor)
return false;
return true;
}
@ -804,7 +880,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
assert(line >= 1);
assert(buffer);
if (!(i = new0(Item, 1))) {
i = new0(Item, 1);
if (!i) {
log_error("Out of memory");
return -ENOMEM;
}
@ -815,19 +892,22 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
"%ms "
"%ms "
"%ms "
"%ms "
"%ms",
&type,
&i->path,
&mode,
&user,
&group,
&age) < 2) {
&age,
&i->argument) < 2) {
log_error("[%s:%u] Syntax error.", fname, line);
r = -EIO;
goto finish;
}
switch(type) {
case CREATE_FILE:
case TRUNCATE_FILE:
case CREATE_DIRECTORY:
@ -839,11 +919,41 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
case RELABEL_PATH:
case RECURSIVE_RELABEL_PATH:
break;
case CREATE_SYMLINK:
if (!i->argument) {
log_error("[%s:%u] Symlink file requires argument.", fname, line);
r = -EBADMSG;
goto finish;
}
break;
case CREATE_CHAR_DEVICE:
case CREATE_BLOCK_DEVICE: {
unsigned major, minor;
if (!i->argument) {
log_error("[%s:%u] Device file requires argument.", fname, line);
r = -EBADMSG;
goto finish;
}
if (sscanf(i->argument, "%u:%u", &major, &minor) != 2) {
log_error("[%s:%u] Can't parse device file major/minor '%s'.", fname, line, i->argument);
r = -EBADMSG;
goto finish;
}
i->major_minor = makedev(major, minor);
break;
}
default:
log_error("[%s:%u] Unknown file type '%c'.", fname, line, type);
r = -EBADMSG;
goto finish;
}
i->type = type;
if (!path_is_absolute(i->path)) {
@ -895,7 +1005,9 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
i->mode = m;
i->mode_set = true;
} else
i->mode = i->type == CREATE_DIRECTORY ? 0755 : 0644;
i->mode =
i->type == CREATE_DIRECTORY ||
i->type == TRUNCATE_DIRECTORY ? 0755 : 0644;
if (age && !streq(age, "-")) {
if (parse_usec(age, &i->age) < 0) {
@ -909,7 +1021,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
h = needs_glob(i->type) ? globs : items;
if ((existing = hashmap_get(h, i->path))) {
existing = hashmap_get(h, i->path);
if (existing) {
/* Two identical items are fine */
if (!item_equal(existing, i))
@ -919,7 +1032,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
goto finish;
}
if ((r = hashmap_put(h, i->path, i)) < 0) {
r = hashmap_put(h, i->path, i);
if (r < 0) {
log_error("Failed to insert item %s: %s", i->path, strerror(-r));
goto finish;
}
@ -1024,7 +1138,8 @@ static int read_config_file(const char *fn, bool ignore_enoent) {
assert(fn);
if (!(f = fopen(fn, "re"))) {
f = fopen(fn, "re");
if (!f) {
if (ignore_enoent && errno == ENOENT)
return 0;