[PATCH] udev - reverse user query options
Here we get the ability to query with the name of the node instead of the device path. It uses a linear search over the whole database. kay@pim:~/src/udev.kay$ ./udev -q path -n video/webcam0 /class/video4linux/video0 New version, with better function return codes for error handling.
This commit is contained in:
kay.sievers@vrfy.org
Greg KH
parent
7780509143
commit
b2a21a3547
7
udev.8
7
udev.8
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@ -50,10 +50,13 @@ will be prepended.
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.BI -q " query_type"
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Query the database for specified value of a created device node.
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Valid types are:
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.BR name ", " symlink ", " owner " or " group .
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.BR name ", " symlink ", " owner " , " group " or " path.
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.TP
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.BI -p " sysfs_path"
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Specify the sysfs path needed for the query.
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Specify the sysfs path of the device to query.
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.TP
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.BI -n " name"
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Specify the name of the node for the device to query.
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.TP
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.B -d
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Dump the whole database.
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104
udev.c
104
udev.c
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@ -83,7 +83,8 @@ static inline char *get_seqnum(void)
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return seqnum;
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}
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static void print_record(char *path, struct udevice *dev)
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/* callback for database dump */
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static int print_record(char *path, struct udevice *dev)
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{
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printf("P: %s\n", path);
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printf("N: %s\n", dev->name);
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@ -91,11 +92,13 @@ static void print_record(char *path, struct udevice *dev)
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printf("O: %s\n", dev->owner);
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printf("G: %s\n", dev->group);
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printf("\n");
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return 0;
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}
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enum query_type {
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NONE,
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NAME,
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PATH,
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SYMLINK,
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OWNER,
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GROUP
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@ -103,7 +106,7 @@ enum query_type {
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static inline int udev_user(int argc, char **argv)
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{
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static const char short_options[] = "dp:q:rVh";
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static const char short_options[] = "dn:p:q:rVh";
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int option;
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int retval = -EINVAL;
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struct udevice dev;
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@ -111,6 +114,7 @@ static inline int udev_user(int argc, char **argv)
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enum query_type query = NONE;
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char result[NAME_SIZE] = "";
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char path[NAME_SIZE] = "";
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char name[NAME_SIZE] = "";
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/* get command line options */
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while (1) {
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@ -120,6 +124,11 @@ static inline int udev_user(int argc, char **argv)
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dbg("option '%c'", option);
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switch (option) {
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case 'n':
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dbg("udev name: %s\n", optarg);
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strfieldcpy(name, optarg);
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break;
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case 'p':
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dbg("udev path: %s\n", optarg);
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strfieldcpy(path, optarg);
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@ -148,6 +157,11 @@ static inline int udev_user(int argc, char **argv)
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break;
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}
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if (strcmp(optarg, "path") == 0) {
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query = PATH;
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break;
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}
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printf("unknown query type\n");
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return -EINVAL;
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@ -161,7 +175,7 @@ static inline int udev_user(int argc, char **argv)
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printf("unable to open udev database\n");
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return -EACCES;
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}
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retval = udevdb_dump(print_record);
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retval = udevdb_call_foreach(print_record);
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udevdb_exit();
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return retval;
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@ -179,44 +193,63 @@ static inline int udev_user(int argc, char **argv)
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/* process options */
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if (query != NONE) {
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if (path[0] == '\0') {
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printf("query needs device path specified\n");
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return -EINVAL;
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}
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retval = udevdb_open_ro();
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if (retval != 0) {
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printf("unable to open udev database\n");
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return -EACCES;
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}
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retval = udevdb_get_dev(path, &dev);
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if (retval == 0) {
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switch(query) {
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case NAME:
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if (root)
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strfieldcpy(result, udev_root);
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strncat(result, dev.name, sizeof(result));
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break;
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case SYMLINK:
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strfieldcpy(result, dev.symlink);
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break;
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case GROUP:
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strfieldcpy(result, dev.group);
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break;
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case OWNER:
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strfieldcpy(result, dev.owner);
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break;
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default:
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break;
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if (path[0] != '\0') {
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retval = udevdb_get_dev(path, &dev);
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if (retval != 0) {
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printf("device not found in database\n");
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goto exit;
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}
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printf("%s\n", result);
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} else {
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printf("device not found in udev database\n");
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goto print;
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}
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if (name[0] != '\0') {
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retval = udevdb_get_dev_byname(name, path, &dev);
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if (retval != 0) {
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printf("device not found in database\n");
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goto exit;
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}
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goto print;
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}
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printf("query needs device path(-p) or node name(-n) specified\n");
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goto exit;
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print:
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switch(query) {
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case NAME:
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if (root)
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strfieldcpy(result, udev_root);
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strncat(result, dev.name, sizeof(result));
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break;
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case SYMLINK:
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strfieldcpy(result, dev.symlink);
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break;
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case GROUP:
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strfieldcpy(result, dev.group);
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break;
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case OWNER:
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strfieldcpy(result, dev.owner);
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break;
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case PATH:
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strfieldcpy(result, path);
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break;
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default:
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goto exit;
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}
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printf("%s\n", result);
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exit:
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udevdb_exit();
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return retval;
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}
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@ -227,13 +260,16 @@ static inline int udev_user(int argc, char **argv)
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}
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help:
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printf("Usage: [-pqrdVh]\n"
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printf("Usage: [-npqrdVh]\n"
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" -q TYPE query database for the specified value:\n"
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" 'name' name of device node\n"
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" 'symlink' pointing to node\n"
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" 'owner' of node\n"
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" 'group' of node\n"
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" 'path' sysfs device path\n"
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" -p PATH sysfs device path used for query\n"
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" -n NAME node name used for query\n"
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"\n"
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" -r print udev root\n"
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" -d dump whole database\n"
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" -V print udev version\n"
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49
udevdb.c
49
udevdb.c
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@ -143,25 +143,62 @@ int udevdb_open_ro(void)
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return 0;
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}
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void (*user_record_callback) (char *path, struct udevice *dev);
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static int (*user_record_callback) (char *path, struct udevice *dev);
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static int traverse_callback(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void *state)
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{
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user_record_callback((char*) key.dptr, (struct udevice*) dbuf.dptr);
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return 0;
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return user_record_callback((char*) key.dptr, (struct udevice*) dbuf.dptr);
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}
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/**
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* udevdb_dump: dumps whole database by passing record data to user function
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* udevdb_call_foreach: dumps whole database by passing record data to user function
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* @user_record_handler: user function called for every record in the database
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*/
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int udevdb_dump(void (*user_record_handler) (char *path, struct udevice *dev))
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int udevdb_call_foreach(int (*user_record_handler) (char *path, struct udevice *dev))
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{
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int retval = 0;
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if (user_record_handler == NULL) {
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dbg("invalid user record handling function");
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return -EINVAL;
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}
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user_record_callback = user_record_handler;
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tdb_traverse(udevdb, traverse_callback, NULL);
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retval = tdb_traverse(udevdb, traverse_callback, NULL);
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if (retval < 0)
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return -ENODEV;
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else
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return 0;
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}
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static struct udevice *find_dev;
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static char *find_path;
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static const char *find_name;
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static int find_found;
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static int find_device_by_name(char *path, struct udevice *dev)
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{
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if (strncmp(dev->name, find_name, sizeof(dev->name)) == 0) {
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memcpy(find_dev, dev, sizeof(*find_dev));
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strncpy(find_path, path, NAME_SIZE);
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find_found = 1;
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/* stop search */
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return 1;
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}
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return 0;
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}
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/**
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* udevdb_get_dev_byname: search device with given name by traversing the whole database
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*/
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int udevdb_get_dev_byname(const char *name, char *path, struct udevice *dev)
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{
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find_found = 0;
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find_path = path;
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find_dev = dev;
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find_name = name;
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udevdb_call_foreach(find_device_by_name);
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if (find_found == 1)
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return 0;
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else
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return -1;
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}
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3
udevdb.h
3
udevdb.h
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@ -12,10 +12,11 @@
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extern void udevdb_exit(void);
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extern int udevdb_init(int init_flag);
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extern int udevdb_open_ro(void);
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extern int udevdb_dump(void (*user_record_handler) (char *path, struct udevice *dev));
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extern int udevdb_call_foreach(int (*user_record_handler) (char *path, struct udevice *dev));
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extern int udevdb_add_dev(const char *path, const struct udevice *dev);
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extern int udevdb_get_dev(const char *path, struct udevice *dev);
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extern int udevdb_delete_dev(const char *path);
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extern int udevdb_get_dev_byname(const char *name, char *path, struct udevice *dev);
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#endif /* _UDEVDB_H_ */
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