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https://github.com/sheumann/hush.git
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345 lines
7.9 KiB
C
345 lines
7.9 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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*
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* mdev - Mini udev for busybox
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*
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* Copyright 2005 Rob Landley <rob@landley.net>
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* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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#include "xregex.h"
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struct globals {
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int root_major, root_minor;
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};
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#define G (*(struct globals*)&bb_common_bufsiz1)
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#define root_major (G.root_major)
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#define root_minor (G.root_minor)
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#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
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/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
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static void make_device(char *path, int delete)
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{
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const char *device_name;
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int major, minor, type, len;
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int mode = 0660;
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uid_t uid = 0;
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gid_t gid = 0;
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char *temp = path + strlen(path);
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char *command = NULL;
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/* Try to read major/minor string. Note that the kernel puts \n after
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* the data, so we don't need to worry about null terminating the string
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* because sscanf() will stop at the first nondigit, which \n is. We
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* also depend on path having writeable space after it.
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*/
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if (!delete) {
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strcat(path, "/dev");
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len = open_read_close(path, temp + 1, 64);
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*temp++ = 0;
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if (len < 1)
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return;
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}
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/* Determine device name, type, major and minor */
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device_name = bb_basename(path);
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type = (path[5] == 'c' ? S_IFCHR : S_IFBLK);
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if (ENABLE_FEATURE_MDEV_CONF) {
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FILE *fp;
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char *line, *vline;
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unsigned lineno = 0;
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/* If we have a config file, look up the user settings */
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fp = fopen_or_warn("/etc/mdev.conf", "r");
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if (!fp)
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goto end_parse;
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while ((vline = line = xmalloc_getline(fp)) != NULL) {
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int field;
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/* A pristine copy for command execution. */
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char *orig_line;
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if (ENABLE_FEATURE_MDEV_EXEC)
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orig_line = xstrdup(line);
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++lineno;
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/* Three fields: regex, uid:gid, mode */
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for (field = 0; field < (3 + ENABLE_FEATURE_MDEV_EXEC); ++field) {
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/* Find a non-empty field */
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char *val;
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do {
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val = strtok(vline, " \t");
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vline = NULL;
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} while (val && !*val);
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if (!val) {
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if (field)
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break;
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else
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goto next_line;
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}
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if (field == 0) {
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/* Regex to match this device */
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regex_t match;
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regmatch_t off;
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int result;
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/* Is this it? */
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xregcomp(&match, val, REG_EXTENDED);
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result = regexec(&match, device_name, 1, &off, 0);
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regfree(&match);
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/* If not this device, skip rest of line */
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if (result || off.rm_so || off.rm_eo != strlen(device_name))
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goto next_line;
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} else if (field == 1) {
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/* uid:gid device ownership */
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struct passwd *pass;
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struct group *grp;
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char *str_uid = val;
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char *str_gid = strchr(val, ':');
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if (str_gid)
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*str_gid = '\0', ++str_gid;
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/* Parse UID */
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pass = getpwnam(str_uid);
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if (pass)
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uid = pass->pw_uid;
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else
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uid = strtoul(str_uid, NULL, 10);
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/* parse GID */
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grp = getgrnam(str_gid);
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if (grp)
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gid = grp->gr_gid;
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else
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gid = strtoul(str_gid, NULL, 10);
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} else if (field == 2) {
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/* Mode device permissions */
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mode = strtoul(val, NULL, 8);
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} else if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
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/* Optional command to run */
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const char *s = "@$*";
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const char *s2 = strchr(s, *val);
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if (!s2) {
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/* Force error */
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field = 1;
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break;
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}
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/* Correlate the position in the "@$*" with the delete
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* step so that we get the proper behavior.
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*/
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if ((s2 - s + 1) & (1 << delete))
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command = xstrdup(orig_line + (val + 1 - line));
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}
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}
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/* Did everything parse happily? */
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if (field <= 2)
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bb_error_msg_and_die("bad line %u", lineno);
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next_line:
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free(line);
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if (ENABLE_FEATURE_MDEV_EXEC)
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free(orig_line);
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}
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if (ENABLE_FEATURE_CLEAN_UP)
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fclose(fp);
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end_parse: /* nothing */ ;
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}
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umask(0);
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if (!delete) {
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if (sscanf(temp, "%d:%d", &major, &minor) != 2)
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return;
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if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
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bb_perror_msg_and_die("mknod %s", device_name);
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if (major == root_major && minor == root_minor)
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symlink(device_name, "root");
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if (ENABLE_FEATURE_MDEV_CONF)
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chown(device_name, uid, gid);
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}
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if (command) {
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/* setenv will leak memory, so use putenv */
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char *s = xasprintf("MDEV=%s", device_name);
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putenv(s);
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if (system(command) == -1)
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bb_perror_msg_and_die("cannot run %s", command);
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s[4] = '\0';
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unsetenv(s);
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free(s);
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free(command);
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}
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if (delete)
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remove_file(device_name, FILEUTILS_FORCE);
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}
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/* File callback for /sys/ traversal */
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static int fileAction(const char *fileName, struct stat *statbuf,
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void *userData, int depth)
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{
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size_t len = strlen(fileName) - 4;
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char *scratch = userData;
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if (strcmp(fileName + len, "/dev"))
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return FALSE;
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strcpy(scratch, fileName);
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scratch[len] = 0;
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make_device(scratch, 0);
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return TRUE;
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}
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/* Directory callback for /sys/ traversal */
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static int dirAction(const char *fileName, struct stat *statbuf,
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void *userData, int depth)
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{
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return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
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}
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/* For the full gory details, see linux/Documentation/firmware_class/README
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*
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* Firmware loading works like this:
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* - kernel sets FIRMWARE env var
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* - userspace checks /lib/firmware/$FIRMWARE
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* - userspace waits for /sys/$DEVPATH/loading to appear
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* - userspace writes "1" to /sys/$DEVPATH/loading
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* - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
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* - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
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* - kernel loads firmware into device
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*/
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static void load_firmware(const char *const firmware, const char *const sysfs_path)
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{
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int cnt;
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int firmware_fd, loading_fd, data_fd;
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/* check for $FIRMWARE from kernel */
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/* XXX: dont bother: open(NULL) works same as open("no-such-file")
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* if (!firmware)
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* return;
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*/
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/* check for /lib/firmware/$FIRMWARE */
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xchdir("/lib/firmware");
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firmware_fd = xopen(firmware, O_RDONLY);
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/* in case we goto out ... */
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data_fd = -1;
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/* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
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xchdir(sysfs_path);
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for (cnt = 0; cnt < 30; ++cnt) {
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loading_fd = open("loading", O_WRONLY);
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if (loading_fd == -1)
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sleep(1);
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else
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break;
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}
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if (loading_fd == -1)
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goto out;
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/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
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if (write(loading_fd, "1", 1) != 1)
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goto out;
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/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
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data_fd = open("data", O_WRONLY);
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if (data_fd == -1)
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goto out;
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cnt = bb_copyfd_eof(firmware_fd, data_fd);
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/* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
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if (cnt > 0)
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write(loading_fd, "0", 1);
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else
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write(loading_fd, "-1", 2);
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out:
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if (ENABLE_FEATURE_CLEAN_UP) {
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close(firmware_fd);
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close(loading_fd);
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close(data_fd);
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}
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}
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int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int mdev_main(int argc, char **argv)
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{
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char *action;
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char *env_path;
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RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
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xchdir("/dev");
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if (argc == 2 && !strcmp(argv[1],"-s")) {
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/* Scan:
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* mdev -s
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*/
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struct stat st;
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xstat("/", &st);
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root_major = major(st.st_dev);
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root_minor = minor(st.st_dev);
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recursive_action("/sys/block",
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ACTION_RECURSE | ACTION_FOLLOWLINKS,
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fileAction, dirAction, temp, 0);
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recursive_action("/sys/class",
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ACTION_RECURSE | ACTION_FOLLOWLINKS,
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fileAction, dirAction, temp, 0);
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} else {
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/* Hotplug:
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* env ACTION=... DEVPATH=... mdev
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* ACTION can be "add" or "remove"
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* DEVPATH is like "/block/sda" or "/class/input/mice"
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*/
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action = getenv("ACTION");
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env_path = getenv("DEVPATH");
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if (!action || !env_path)
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bb_show_usage();
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sprintf(temp, "/sys%s", env_path);
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if (!strcmp(action, "remove"))
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make_device(temp, 1);
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else if (!strcmp(action, "add")) {
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make_device(temp, 0);
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if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
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load_firmware(getenv("FIRMWARE"), temp);
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}
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}
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if (ENABLE_FEATURE_CLEAN_UP)
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RELEASE_CONFIG_BUFFER(temp);
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return 0;
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}
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