[PATCH 1/2] static-nodes: don't fail if modules.devname not found

[Tom Gundersen]

In containers/VM's/initrd one might not have installed any modules and accompanying modules.devname
Don't fail if this is the case, just warn.

When used in systemd this means we don't get a failing unit on booting containers.
---
tools/static-nodes.c | 32 ++++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/tools/static-nodes.c b/tools/static-nodes.c
index 96bb71e..b4a3c08 100644
--- a/tools/static-nodes.c
+++ b/tools/static-nodes.c
@@ -155,6 +155,7 @@ static int do_static_nodes(int argc, char *argv[])
{
struct utsname kernel;
char modules[PATH_MAX];
+ char output[PATH_MAX];
FILE *in = NULL, *out = stdout;
const struct static_nodes_format *format = &static_nodes_format_human;
char buf[4096];
@@ -170,13 +171,8 @@ static int do_static_nodes(int argc, char *argv[])
}
switch (c) {
case 'o':
- out = fopen(optarg, "we");
- if (out == NULL) {
- fprintf(stderr, "Error: could not create %s!\n",
- optarg);
- ret = EXIT_FAILURE;
- goto finish;
- }
+ strncpy(output, optarg, PATH_MAX);
+ out = NULL;
break;
case 'f':
valid = 0;
@@ -221,12 +217,28 @@ static int do_static_nodes(int argc, char *argv[])
kernel.release);
in = fopen(modules, "re");
if (in == NULL) {
- fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n",
- kernel.release);
- ret = EXIT_FAILURE;
+ if (errno == ENOENT) {
+ fprintf(stderr, "Warning: /lib/modules/%s/modules.devname not found - ignoring\n",
+ kernel.release);
+ ret = EXIT_SUCCESS;
+ } else {
+ fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n",
+ kernel.release);
+ ret = EXIT_FAILURE;
+ }
goto finish;
}

+ if (out == NULL) {
+ out = fopen(output, "we");
+ if (out == NULL) {
+ fprintf(stderr, "Error: could not create %s!\n",
+ output);
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+ }
+
while (fgets(buf, sizeof(buf), in) != NULL) {
char modname[PATH_MAX];
char devname[PATH_MAX];

[Tom Gundersen]

Allows us to drop call to "mkdir -p" from the systemd service file.
---
Makefile.am | 3 +-
tools/mkdir.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/mkdir.h | 25 ++++++++++++++++
tools/static-nodes.c | 14 ++++++++-
4 files changed, 121 insertions(+), 2 deletions(-)
create mode 100644 tools/mkdir.c
create mode 100644 tools/mkdir.h

diff --git a/Makefile.am b/Makefile.am
index 0ed944c..ab49dfd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -111,7 +111,8 @@ tools_kmod_SOURCES = tools/kmod.c tools/kmod.h tools/lsmod.c \
tools/rmmod.c tools/insmod.c \
tools/modinfo.c tools/modprobe.c \
tools/depmod.c tools/log.h tools/log.c \
- tools/static-nodes.c
+ tools/static-nodes.c tools/mkdir.c \
+ tools/mkdir.h
tools_kmod_LDADD = libkmod/libkmod-util.la \
libkmod/libkmod-internal.la

diff --git a/tools/mkdir.c b/tools/mkdir.c
new file mode 100644
index 0000000..9935366
--- /dev/null
+++ b/tools/mkdir.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2012 Lucas De Marchi <lucas.de.marchi-***@public.gmane.org
+ * Copyright (C) 2013 Tom Gundersen <teg-***@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "mkdir.h"
+
+static int mkdir_p(char *path, mode_t mode)
+{
+ char *end = path + strlen(path);
+ struct stat st;
+ int r;
+
+ /*
+ * don't try to overwrite existing file, succeed if it is a directory,
+ * fail otherwise
+ */
+ if (stat(path, &st) >= 0) {
+ if (S_ISDIR(st.st_mode)) {
+ return 0;
+ } else
+ return -ENOTDIR;
+ }
+
+ /* Find the last '/' */
+ while (end > path && *end != '/')
+ end--;
+
+ /* discard extra '/' */
+ while (end > path && *(end - 1) == '/')
+ end--;
+
+ /* if a parent directory was found, create it recursively */
+ if (end != path) {
+ *end = '\0';
+ r = mkdir_p(path, mode);
+ *end = '/';
+
+ if (r < 0)
+ return -errno;
+ }
+
+ /* create the desired directory */
+ return mkdir(path, mode);
+}
+
+int mkdir_parents(const char *path, mode_t mode) {
+ char *dirname = strdupa(path);
+ char *offset = strrchr(dirname, '/');
+
+ /* no parent directories */
+ if (!offset) {
+ return 0;
+ }
+
+ /* compute the dirname */
+ while (*(offset - 1) == '/')
+ offset--;
+ *offset = '\0';
+
+ return mkdir_p(dirname, mode);
+}
diff --git a/tools/mkdir.h b/tools/mkdir.h
new file mode 100644
index 0000000..5327fbe
--- /dev/null
+++ b/tools/mkdir.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2012 Lucas De Marchi <lucas.de.marchi-***@public.gmane.org>
+ * Copyright (C) 2013 Tom Gundersen <teg-***@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#pragma once
+
+#include <sys/stat.h>
+#include <sys/types.h>
+
+int mkdir_parents(const char *path, mode_t mode);
diff --git a/tools/static-nodes.c b/tools/static-nodes.c
index b4a3c08..fb2d633 100644
--- a/tools/static-nodes.c
+++ b/tools/static-nodes.c
@@ -32,6 +32,8 @@
#include <sys/types.h>
#include "libkmod-util.h"

+#include "mkdir.h"
+
#include "kmod.h"

struct static_nodes_format {
@@ -230,9 +232,19 @@ static int do_static_nodes(int argc, char *argv[])
}

if (out == NULL) {
+ int r;
+
+ r = mkdir_parents(output, 0755);
+ if (r < 0) {
+ fprintf(stderr, "Error: could not create parent directory for %s - %m.\n",
+ output);
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+
out = fopen(output, "we");
if (out == NULL) {
- fprintf(stderr, "Error: could not create %s!\n",
+ fprintf(stderr, "Error: could not create %s - %m\n",
output);
ret = EXIT_FAILURE;
goto finish;

[Dave Reisner]

Post by Tom Gundersen
In containers/VM's/initrd one might not have installed any modules and accompanying modules.devname
Don't fail if this is the case, just warn.
When used in systemd this means we don't get a failing unit on booting containers.
---
tools/static-nodes.c | 32 ++++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/tools/static-nodes.c b/tools/static-nodes.c
index 96bb71e..b4a3c08 100644
--- a/tools/static-nodes.c
+++ b/tools/static-nodes.c
@@ -155,6 +155,7 @@ static int do_static_nodes(int argc, char *argv[])
{
struct utsname kernel;
char modules[PATH_MAX];
+ char output[PATH_MAX];
FILE *in = NULL, *out = stdout;
const struct static_nodes_format *format = &static_nodes_format_human;
char buf[4096];
@@ -170,13 +171,8 @@ static int do_static_nodes(int argc, char *argv[])
}
switch (c) {
- out = fopen(optarg, "we");
- if (out == NULL) {
- fprintf(stderr, "Error: could not create %s!\n",
- optarg);
- ret = EXIT_FAILURE;
- goto finish;
- }
+ strncpy(output, optarg, PATH_MAX);

No need to copy anything here, just retain a pointer to this optarg.

Post by Tom Gundersen
+ out = NULL;
break;
valid = 0;
@@ -221,12 +217,28 @@ static int do_static_nodes(int argc, char *argv[])
kernel.release);
in = fopen(modules, "re");
if (in == NULL) {
- fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n",
- kernel.release);
- ret = EXIT_FAILURE;
+ if (errno == ENOENT) {
+ fprintf(stderr, "Warning: /lib/modules/%s/modules.devname not found - ignoring\n",
+ kernel.release);
+ ret = EXIT_SUCCESS;
+ } else {
+ fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n",
+ kernel.release);
+ ret = EXIT_FAILURE;
+ }
goto finish;
}
+ if (out == NULL) {

It took me a minute to realize why this was the correct comparison.
Maybe it's just me, but I think this would be more readable if we did
something like the below psuedocode

const char* output = "/dev/stderr";
/* do option parsing, maybe reassigning 'output' */

/* now open the file, regardless of what it is */
FILE* out = fopen(output, "we");
if (out == NULL)
...

Seems a bit cleaner to me, even if it duplicates a file descriptor (but
we'll open a new FILE regardless in the common use case).

Post by Tom Gundersen
+ out = fopen(output, "we");
+ if (out == NULL) {
+ fprintf(stderr, "Error: could not create %s!\n",
+ output);

I realize this is copied from the old code, but there's no explanation
as to why this failed. Add an %m token to the format string?

Post by Tom Gundersen
+ ret = EXIT_FAILURE;
+ goto finish;
+ }
+ }
+
while (fgets(buf, sizeof(buf), in) != NULL) {
char modname[PATH_MAX];
char devname[PATH_MAX];
--
1.8.3.2
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[Tom Gundersen]

Post by Dave Reisner

+ strncpy(output, optarg, PATH_MAX);

No need to copy anything here, just retain a pointer to this optarg.

Fixed.

Post by Dave Reisner

+ if (out == NULL) {

It took me a minute to realize why this was the correct comparison.
Maybe it's just me, but I think this would be more readable if we did
something like the below psuedocode
const char* output = "/dev/stderr";
/* do option parsing, maybe reassigning 'output' */
/* now open the file, regardless of what it is */
FILE* out = fopen(output, "we");
if (out == NULL)
...
Seems a bit cleaner to me, even if it duplicates a file descriptor (but
we'll open a new FILE regardless in the common use case).

Yeah, makes sense to me, I'll do that instead.

Post by Dave Reisner

+ out = fopen(output, "we");
+ if (out == NULL) {
+ fprintf(stderr, "Error: could not create %s!\n",
+ output);

I realize this is copied from the old code, but there's no explanation
as to why this failed. Add an %m token to the format string?

For some reason that change ended up in the subsequent patch, anyway,
moving it to this one where it belong.

Thanks.

Tom

[Kay Sievers]

Post by Tom Gundersen
@@ -170,13 +171,8 @@ static int do_static_nodes(int argc, char *argv[])
}
switch (c) {
- out = fopen(optarg, "we");
- if (out == NULL) {
- fprintf(stderr, "Error: could not create %s!\n",
- optarg);
- ret = EXIT_FAILURE;
- goto finish;
- }
+ strncpy(output, optarg, PATH_MAX);

Not relevant for any common use case, but strncpy() sucks and will not
terminate with '\0', so we should probably just always add a '\0' to
the end.

Kay