mirror of
https://github.com/sheumann/hush.git
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494 lines
12 KiB
C
494 lines
12 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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/* Prevent infinite loops in /sys symlinks */
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#define MAX_SYSFS_DEPTH 3
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/* We use additional 64+ bytes in make_device() */
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#define SCRATCH_SIZE 80
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#if ENABLE_FEATURE_MDEV_RENAME
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/* Builds an alias path.
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* This function potentionally reallocates the alias parameter.
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*/
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static char *build_alias(char *alias, const char *device_name)
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{
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char *dest;
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/* ">bar/": rename to bar/device_name */
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/* ">bar[/]baz": rename to bar[/]baz */
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dest = strrchr(alias, '/');
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if (dest) { /* ">bar/[baz]" ? */
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*dest = '\0'; /* mkdir bar */
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bb_make_directory(alias, 0755, FILEUTILS_RECUR);
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*dest = '/';
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if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
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dest = alias;
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alias = concat_path_file(alias, device_name);
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free(dest);
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}
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}
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return alias;
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}
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#endif
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/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
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/* NB: "mdev -s" may call us many times, do not leak memory/fds! */
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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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#if ENABLE_FEATURE_MDEV_CONF
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struct bb_uidgid_t ugid = { 0, 0 };
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parser_t *parser;
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char *tokens[5];
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#endif
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#if ENABLE_FEATURE_MDEV_EXEC
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char *command = NULL;
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#endif
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#if ENABLE_FEATURE_MDEV_RENAME
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char *alias = NULL;
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char aliaslink = aliaslink; /* for compiler */
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#endif
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char *dev_maj_min = path + strlen(path);
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/* Force the configuration file settings exactly. */
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umask(0);
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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.
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* We also depend on path having writeable space after it.
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*/
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major = -1;
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if (!delete) {
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strcpy(dev_maj_min, "/dev");
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len = open_read_close(path, dev_maj_min + 1, 64);
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*dev_maj_min++ = '\0';
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if (len < 1) {
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if (!ENABLE_FEATURE_MDEV_EXEC)
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return;
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/* no "dev" file, so just try to run script */
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*dev_maj_min = '\0';
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} else if (sscanf(dev_maj_min, "%u:%u", &major, &minor) != 2) {
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major = -1;
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}
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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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/* http://kernel.org/doc/pending/hotplug.txt says that only
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* "/sys/block/..." is for block devices. "/sys/bus" etc is not.
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* But since 2.6.25 block devices are also in /sys/class/block.
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* We use strstr("/block/") to forestall future surprises. */
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type = S_IFCHR;
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if (strstr(path, "/block/"))
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type = S_IFBLK;
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#if ENABLE_FEATURE_MDEV_CONF
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parser = config_open2("/etc/mdev.conf", fopen_for_read);
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/* If we have config file, look up user settings */
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while (config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
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regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
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char *val;
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/* Fields: regex uid:gid mode [alias] [cmd] */
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/* 1st field: @<numeric maj,min>... */
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if (tokens[0][0] == '@') {
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/* @major,minor[-last] */
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/* (useful when name is ambiguous:
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* "/sys/class/usb/lp0" and
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* "/sys/class/printer/lp0") */
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int cmaj, cmin0, cmin1, sc;
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if (major < 0)
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continue; /* no dev, no match */
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sc = sscanf(tokens[0], "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
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if (sc < 1 || major != cmaj
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|| (sc == 2 && minor != cmin0)
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|| (sc == 3 && (minor < cmin0 || minor > cmin1))
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) {
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continue; /* no match */
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}
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} else { /* ... or regex to match device name */
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regex_t match;
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int result;
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/* Is this it? */
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xregcomp(&match, tokens[0], REG_EXTENDED);
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result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
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regfree(&match);
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//bb_error_msg("matches:");
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//for (int i = 0; i < ARRAY_SIZE(off); i++) {
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// if (off[i].rm_so < 0) continue;
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// bb_error_msg("match %d: '%.*s'\n", i,
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// (int)(off[i].rm_eo - off[i].rm_so),
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// device_name + off[i].rm_so);
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//}
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/* If not this device, skip rest of line */
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/* (regexec returns whole pattern as "range" 0) */
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if (result || off[0].rm_so
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|| ((int)off[0].rm_eo != (int)strlen(device_name))
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) {
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continue;
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}
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}
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/* This line matches: stop parsing the file
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* after parsing the rest of fields */
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/* 2nd field: uid:gid - device ownership */
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parse_chown_usergroup_or_die(&ugid, tokens[1]);
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/* 3rd field: mode - device permissions */
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mode = strtoul(tokens[2], NULL, 8);
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val = tokens[3];
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/* 4th field (opt): >alias */
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#if ENABLE_FEATURE_MDEV_RENAME
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if (!val)
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break;
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aliaslink = *val;
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if (aliaslink == '>' || aliaslink == '=') {
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char *s;
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#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
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char *p;
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unsigned i, n;
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#endif
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char *a = val;
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s = strchrnul(val, ' ');
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val = (s[0] && s[1]) ? s+1 : NULL;
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s[0] = '\0';
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#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
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/* substitute %1..9 with off[1..9], if any */
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n = 0;
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s = a;
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while (*s)
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if (*s++ == '%')
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n++;
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p = alias = xzalloc(strlen(a) + n * strlen(device_name));
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s = a + 1;
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while (*s) {
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*p = *s;
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if ('%' == *s) {
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i = (s[1] - '0');
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if (i <= 9 && off[i].rm_so >= 0) {
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n = off[i].rm_eo - off[i].rm_so;
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strncpy(p, device_name + off[i].rm_so, n);
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p += n - 1;
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s++;
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}
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}
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p++;
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s++;
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}
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#else
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alias = xstrdup(a + 1);
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#endif
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}
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#endif /* ENABLE_FEATURE_MDEV_RENAME */
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#if ENABLE_FEATURE_MDEV_EXEC
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/* The rest (opt): command to run */
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if (!val)
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break;
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{
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const char *s = "@$*";
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const char *s2 = strchr(s, *val);
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if (!s2)
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bb_error_msg_and_die("bad line %u", parser->lineno);
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/* Correlate the position in the "@$*" with the delete
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* step so that we get the proper behavior:
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* @cmd: run on create
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* $cmd: run on delete
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* *cmd: run on both
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*/
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if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
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command = xstrdup(val + 1);
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}
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}
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#endif
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/* end of field parsing */
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break; /* we found matching line, stop */
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} /* end of "while line is read from /etc/mdev.conf" */
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config_close(parser);
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#endif /* ENABLE_FEATURE_MDEV_CONF */
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if (!delete && major >= 0) {
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if (ENABLE_FEATURE_MDEV_RENAME)
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unlink(device_name);
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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, ugid.uid, ugid.gid);
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#if ENABLE_FEATURE_MDEV_RENAME
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if (alias) {
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alias = build_alias(alias, device_name);
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/* move the device, and optionally
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* make a symlink to moved device node */
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if (rename(device_name, alias) == 0 && aliaslink == '>')
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symlink(alias, device_name);
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free(alias);
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}
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#endif
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#endif
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}
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#if ENABLE_FEATURE_MDEV_EXEC
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if (command) {
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/* setenv will leak memory, use putenv/unsetenv/free */
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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("can't run '%s'", command);
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unsetenv("MDEV");
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free(s);
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free(command);
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}
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#endif
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if (delete) {
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unlink(device_name);
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/* At creation time, device might have been moved
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* and a symlink might have been created. Undo that. */
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#if ENABLE_FEATURE_MDEV_RENAME
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if (alias) {
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alias = build_alias(alias, device_name);
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unlink(alias);
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free(alias);
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}
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#endif
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}
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}
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/* File callback for /sys/ traversal */
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static int FAST_FUNC fileAction(const char *fileName,
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struct stat *statbuf UNUSED_PARAM,
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void *userData,
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int depth UNUSED_PARAM)
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{
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size_t len = strlen(fileName) - 4; /* can't underflow */
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char *scratch = userData;
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/* len check is for paranoid reasons */
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if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
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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 FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
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struct stat *statbuf UNUSED_PARAM,
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void *userData UNUSED_PARAM,
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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/$DEVPATH/loading
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* - kernel loads firmware into device
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*/
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static void load_firmware(const char *const firmware, const char *const sysfs_path)
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{
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int cnt;
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int firmware_fd, loading_fd, data_fd;
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/* check for /lib/firmware/$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/$DEVPATH/loading ... give 30 seconds to appear */
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xchdir(sysfs_path);
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for (cnt = 0; cnt < 30; ++cnt) {
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loading_fd = open("loading", O_WRONLY);
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if (loading_fd != -1)
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goto loading;
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sleep(1);
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}
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goto out;
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loading:
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/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
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if (full_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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full_write(loading_fd, "0", 1);
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else
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full_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 UNUSED_PARAM, char **argv)
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{
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RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
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/* We can be called as hotplug helper */
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/* Kernel cannot provide suitable stdio fds for us, do it ourself */
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#if 1
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bb_sanitize_stdio();
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#else
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/* Debug code */
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/* Replace LOGFILE by other file or device name if you need */
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#define LOGFILE "/dev/console"
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/* Just making sure fd 0 is not closed,
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* we don't really intend to read from it */
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xmove_fd(xopen("/", O_RDONLY), STDIN_FILENO);
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xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO);
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xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
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#endif
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xchdir("/dev");
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if (argv[1] && !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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/* ACTION_FOLLOWLINKS is needed since in newer kernels
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* /sys/block/loop* (for example) are symlinks to dirs,
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* not real directories.
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* (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
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* but we can't enforce that on users)
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*/
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if (access("/sys/class/block", F_OK) != 0) {
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/* Scan obsolete /sys/block only if /sys/class/block
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* doesn't exist. Otherwise we'll have dupes.
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*/
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recursive_action("/sys/block",
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ACTION_RECURSE | ACTION_FOLLOWLINKS,
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// not needed now? | ACTION_QUIET
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fileAction, dirAction, temp, 0);
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}
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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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char *seq;
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char *action;
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char *env_path;
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char seqbuf[sizeof(int)*3 + 2];
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int seqlen = seqlen; /* for compiler */
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/* Hotplug:
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* env ACTION=... DEVPATH=... [SEQNUM=...] 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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seq = getenv("SEQNUM");
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if (seq) {
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int timeout = 2000 / 32;
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do {
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seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
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if (seqlen < 0)
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break;
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seqbuf[seqlen] = '\0';
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if (seqbuf[0] == '\n' /* seed file? */
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|| strcmp(seq, seqbuf) == 0 /* correct idx? */
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) {
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break;
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}
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usleep(32*1000);
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} while (--timeout);
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}
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snprintf(temp, PATH_MAX, "/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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char *fw = getenv("FIRMWARE");
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if (fw)
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load_firmware(fw, temp);
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}
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}
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if (seq && seqlen >= 0) {
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xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
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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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