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20a3262cd

Denys Vlasenko

2016-09-07

SUCCESS Duration: 262s

Subject

mdev: create devices from /sys/dev

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

util-linux/mdev.c +41 -47

util-linux/mdev.c+41 -47

@@ -543,8 +543,7 @@ static char build_alias(char alias, const char *device_name)

	/* mknod in /dev based on a path like "/sys/block/hda/hda1"
	* NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
-	* after NUL, but we promise to not mangle (IOW: to restore NUL if needed)
-	* path string.
+	* after NUL, but we promise to not mangle it (IOW: to restore NUL if needed).
	* NB2: "mdev -s" may call us many times, do not leak memory/fds!
	*
	* device_name = $DEVNAME (may be NULL)
@@ -810,41 +809,39 @@ static void make_device(char device_name, char path, int operation)
	} /* for (;;) */
	}

-	/* File callback for /sys/ traversal */
+	/* File callback for /sys/ traversal.
+	* We act only on "/sys/.../dev" (pseudo)file
+	*/
	static int FAST_FUNC fileAction(const char *fileName,
	struct stat *statbuf UNUSED_PARAM,
	void *userData,
	int depth UNUSED_PARAM)
	{
	size_t len = strlen(fileName) - 4; /* can't underflow */
-	char *scratch = userData;
-
-	/* len check is for paranoid reasons */
-	if (strcmp(fileName + len, "/dev") != 0 \|\| len >= PATH_MAX)
-	return FALSE;
-
-	strcpy(scratch, fileName);
-	scratch[len] = '\0';
-	make_device(/DEVNAME:/ NULL, scratch, OP_add);
-
-	return TRUE;
-	}
-
-	/* Directory callback for /sys/ traversal */
-	static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
-	struct stat *statbuf UNUSED_PARAM,
-	void *userData UNUSED_PARAM,
-	int depth)
-	{
-	/* Extract device subsystem -- the name of the directory
-	* under /sys/class/ */
-	if (1 == depth) {
+	char path = userData; / char array[PATH_MAX + SCRATCH_SIZE] */
+	char subsys[PATH_MAX];
+	int res;
+
+	/* Is it a ".../dev" file? (len check is for paranoid reasons) */
+	if (strcmp(fileName + len, "/dev") != 0 \|\| len >= PATH_MAX - 32)
+	return FALSE; /* not .../dev */
+
+	strcpy(path, fileName);
+	path[len] = '\0';
+
+	/* Read ".../subsystem" symlink in the same directory where ".../dev" is */
+	strcpy(subsys, path);
+	strcpy(subsys + len, "/subsystem");
+	res = readlink(subsys, subsys, sizeof(subsys)-1);
+	if (res > 0) {
+	subsys[res] = '\0';
	free(G.subsystem);
	if (G.subsys_env) {
	bb_unsetenv_and_free(G.subsys_env);
	G.subsys_env = NULL;
	}
-	G.subsystem = strrchr(fileName, '/');
+	/* Set G.subsystem and $SUBSYSTEM from symlink's last component */
+	G.subsystem = strrchr(subsys, '/');
	if (G.subsystem) {
	G.subsystem = xstrdup(G.subsystem + 1);
	G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
@@ -852,6 +849,17 @@ static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
	}
	}

+	make_device(/DEVNAME:/ NULL, path, OP_add);
+
+	return TRUE;
+	}
+
+	/* Directory callback for /sys/ traversal */
+	static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
+	struct stat *statbuf UNUSED_PARAM,
+	void *userData UNUSED_PARAM,
+	int depth)
+	{
	return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
	}

@@ -872,8 +880,9 @@ static void load_firmware(const char firmware, const char sysfs_path)
	int firmware_fd, loading_fd;

	/* check for /lib/firmware/$FIRMWARE */
-	xchdir("/lib/firmware");
-	firmware_fd = open(firmware, O_RDONLY); /* can fail */
+	firmware_fd = -1;
+	if (chdir("/lib/firmware") == 0)
+	firmware_fd = open(firmware, O_RDONLY); /* can fail */

	/* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
	xchdir(sysfs_path);
@@ -1065,25 +1074,10 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)

	putenv((char*)"ACTION=add");

-	/* ACTION_FOLLOWLINKS is needed since in newer kernels
-	* /sys/block/loop* (for example) are symlinks to dirs,
-	* not real directories.
-	* (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
-	* but we can't enforce that on users)
-	*/
-	if (access("/sys/class/block", F_OK) != 0) {
-	/* Scan obsolete /sys/block only if /sys/class/block
-	* doesn't exist. Otherwise we'll have dupes.
-	* Also, do not complain if it doesn't exist.
-	* Some people configure kernel to have no blockdevs.
-	*/
-	recursive_action("/sys/block",
-	ACTION_RECURSE \| ACTION_FOLLOWLINKS \| ACTION_QUIET,
-	fileAction, dirAction, temp, 0);
-	}
-	recursive_action("/sys/class",
-	ACTION_RECURSE \| ACTION_FOLLOWLINKS,
-	fileAction, dirAction, temp, 0);
+	/* Create all devices from /sys/dev hierarchy */
+	recursive_action("/sys/dev",
+	ACTION_RECURSE \| ACTION_FOLLOWLINKS,
+	fileAction, dirAction, temp, 0);
	} else {
	char *fw;
	char *seq;