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-rw-r--r--fs/exec.c688
1 files changed, 7 insertions, 681 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 574cf4de4ec3..48fb26ef8a1b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -66,19 +66,8 @@
66 66
67#include <trace/events/sched.h> 67#include <trace/events/sched.h>
68 68
69int core_uses_pid;
70char core_pattern[CORENAME_MAX_SIZE] = "core";
71unsigned int core_pipe_limit;
72int suid_dumpable = 0; 69int suid_dumpable = 0;
73 70
74struct core_name {
75 char *corename;
76 int used, size;
77};
78static atomic_t call_count = ATOMIC_INIT(1);
79
80/* The maximal length of core_pattern is also specified in sysctl.c */
81
82static LIST_HEAD(formats); 71static LIST_HEAD(formats);
83static DEFINE_RWLOCK(binfmt_lock); 72static DEFINE_RWLOCK(binfmt_lock);
84 73
@@ -1006,40 +995,6 @@ no_thread_group:
1006 return 0; 995 return 0;
1007} 996}
1008 997
1009/*
1010 * These functions flushes out all traces of the currently running executable
1011 * so that a new one can be started
1012 */
1013static void flush_old_files(struct files_struct * files)
1014{
1015 long j = -1;
1016 struct fdtable *fdt;
1017
1018 spin_lock(&files->file_lock);
1019 for (;;) {
1020 unsigned long set, i;
1021
1022 j++;
1023 i = j * BITS_PER_LONG;
1024 fdt = files_fdtable(files);
1025 if (i >= fdt->max_fds)
1026 break;
1027 set = fdt->close_on_exec[j];
1028 if (!set)
1029 continue;
1030 fdt->close_on_exec[j] = 0;
1031 spin_unlock(&files->file_lock);
1032 for ( ; set ; i++,set >>= 1) {
1033 if (set & 1) {
1034 sys_close(i);
1035 }
1036 }
1037 spin_lock(&files->file_lock);
1038
1039 }
1040 spin_unlock(&files->file_lock);
1041}
1042
1043char *get_task_comm(char *buf, struct task_struct *tsk) 998char *get_task_comm(char *buf, struct task_struct *tsk)
1044{ 999{
1045 /* buf must be at least sizeof(tsk->comm) in size */ 1000 /* buf must be at least sizeof(tsk->comm) in size */
@@ -1050,6 +1005,11 @@ char *get_task_comm(char *buf, struct task_struct *tsk)
1050} 1005}
1051EXPORT_SYMBOL_GPL(get_task_comm); 1006EXPORT_SYMBOL_GPL(get_task_comm);
1052 1007
1008/*
1009 * These functions flushes out all traces of the currently running executable
1010 * so that a new one can be started
1011 */
1012
1053void set_task_comm(struct task_struct *tsk, char *buf) 1013void set_task_comm(struct task_struct *tsk, char *buf)
1054{ 1014{
1055 task_lock(tsk); 1015 task_lock(tsk);
@@ -1171,7 +1131,7 @@ void setup_new_exec(struct linux_binprm * bprm)
1171 current->self_exec_id++; 1131 current->self_exec_id++;
1172 1132
1173 flush_signal_handlers(current, 0); 1133 flush_signal_handlers(current, 0);
1174 flush_old_files(current->files); 1134 do_close_on_exec(current->files);
1175} 1135}
1176EXPORT_SYMBOL(setup_new_exec); 1136EXPORT_SYMBOL(setup_new_exec);
1177 1137
@@ -1632,353 +1592,6 @@ void set_binfmt(struct linux_binfmt *new)
1632 1592
1633EXPORT_SYMBOL(set_binfmt); 1593EXPORT_SYMBOL(set_binfmt);
1634 1594
1635static int expand_corename(struct core_name *cn)
1636{
1637 char *old_corename = cn->corename;
1638
1639 cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
1640 cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
1641
1642 if (!cn->corename) {
1643 kfree(old_corename);
1644 return -ENOMEM;
1645 }
1646
1647 return 0;
1648}
1649
1650static int cn_printf(struct core_name *cn, const char *fmt, ...)
1651{
1652 char *cur;
1653 int need;
1654 int ret;
1655 va_list arg;
1656
1657 va_start(arg, fmt);
1658 need = vsnprintf(NULL, 0, fmt, arg);
1659 va_end(arg);
1660
1661 if (likely(need < cn->size - cn->used - 1))
1662 goto out_printf;
1663
1664 ret = expand_corename(cn);
1665 if (ret)
1666 goto expand_fail;
1667
1668out_printf:
1669 cur = cn->corename + cn->used;
1670 va_start(arg, fmt);
1671 vsnprintf(cur, need + 1, fmt, arg);
1672 va_end(arg);
1673 cn->used += need;
1674 return 0;
1675
1676expand_fail:
1677 return ret;
1678}
1679
1680static void cn_escape(char *str)
1681{
1682 for (; *str; str++)
1683 if (*str == '/')
1684 *str = '!';
1685}
1686
1687static int cn_print_exe_file(struct core_name *cn)
1688{
1689 struct file *exe_file;
1690 char *pathbuf, *path;
1691 int ret;
1692
1693 exe_file = get_mm_exe_file(current->mm);
1694 if (!exe_file) {
1695 char *commstart = cn->corename + cn->used;
1696 ret = cn_printf(cn, "%s (path unknown)", current->comm);
1697 cn_escape(commstart);
1698 return ret;
1699 }
1700
1701 pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
1702 if (!pathbuf) {
1703 ret = -ENOMEM;
1704 goto put_exe_file;
1705 }
1706
1707 path = d_path(&exe_file->f_path, pathbuf, PATH_MAX);
1708 if (IS_ERR(path)) {
1709 ret = PTR_ERR(path);
1710 goto free_buf;
1711 }
1712
1713 cn_escape(path);
1714
1715 ret = cn_printf(cn, "%s", path);
1716
1717free_buf:
1718 kfree(pathbuf);
1719put_exe_file:
1720 fput(exe_file);
1721 return ret;
1722}
1723
1724/* format_corename will inspect the pattern parameter, and output a
1725 * name into corename, which must have space for at least
1726 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1727 */
1728static int format_corename(struct core_name *cn, long signr)
1729{
1730 const struct cred *cred = current_cred();
1731 const char *pat_ptr = core_pattern;
1732 int ispipe = (*pat_ptr == '|');
1733 int pid_in_pattern = 0;
1734 int err = 0;
1735
1736 cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
1737 cn->corename = kmalloc(cn->size, GFP_KERNEL);
1738 cn->used = 0;
1739
1740 if (!cn->corename)
1741 return -ENOMEM;
1742
1743 /* Repeat as long as we have more pattern to process and more output
1744 space */
1745 while (*pat_ptr) {
1746 if (*pat_ptr != '%') {
1747 if (*pat_ptr == 0)
1748 goto out;
1749 err = cn_printf(cn, "%c", *pat_ptr++);
1750 } else {
1751 switch (*++pat_ptr) {
1752 /* single % at the end, drop that */
1753 case 0:
1754 goto out;
1755 /* Double percent, output one percent */
1756 case '%':
1757 err = cn_printf(cn, "%c", '%');
1758 break;
1759 /* pid */
1760 case 'p':
1761 pid_in_pattern = 1;
1762 err = cn_printf(cn, "%d",
1763 task_tgid_vnr(current));
1764 break;
1765 /* uid */
1766 case 'u':
1767 err = cn_printf(cn, "%d", cred->uid);
1768 break;
1769 /* gid */
1770 case 'g':
1771 err = cn_printf(cn, "%d", cred->gid);
1772 break;
1773 /* signal that caused the coredump */
1774 case 's':
1775 err = cn_printf(cn, "%ld", signr);
1776 break;
1777 /* UNIX time of coredump */
1778 case 't': {
1779 struct timeval tv;
1780 do_gettimeofday(&tv);
1781 err = cn_printf(cn, "%lu", tv.tv_sec);
1782 break;
1783 }
1784 /* hostname */
1785 case 'h': {
1786 char *namestart = cn->corename + cn->used;
1787 down_read(&uts_sem);
1788 err = cn_printf(cn, "%s",
1789 utsname()->nodename);
1790 up_read(&uts_sem);
1791 cn_escape(namestart);
1792 break;
1793 }
1794 /* executable */
1795 case 'e': {
1796 char *commstart = cn->corename + cn->used;
1797 err = cn_printf(cn, "%s", current->comm);
1798 cn_escape(commstart);
1799 break;
1800 }
1801 case 'E':
1802 err = cn_print_exe_file(cn);
1803 break;
1804 /* core limit size */
1805 case 'c':
1806 err = cn_printf(cn, "%lu",
1807 rlimit(RLIMIT_CORE));
1808 break;
1809 default:
1810 break;
1811 }
1812 ++pat_ptr;
1813 }
1814
1815 if (err)
1816 return err;
1817 }
1818
1819 /* Backward compatibility with core_uses_pid:
1820 *
1821 * If core_pattern does not include a %p (as is the default)
1822 * and core_uses_pid is set, then .%pid will be appended to
1823 * the filename. Do not do this for piped commands. */
1824 if (!ispipe && !pid_in_pattern && core_uses_pid) {
1825 err = cn_printf(cn, ".%d", task_tgid_vnr(current));
1826 if (err)
1827 return err;
1828 }
1829out:
1830 return ispipe;
1831}
1832
1833static int zap_process(struct task_struct *start, int exit_code)
1834{
1835 struct task_struct *t;
1836 int nr = 0;
1837
1838 start->signal->flags = SIGNAL_GROUP_EXIT;
1839 start->signal->group_exit_code = exit_code;
1840 start->signal->group_stop_count = 0;
1841
1842 t = start;
1843 do {
1844 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1845 if (t != current && t->mm) {
1846 sigaddset(&t->pending.signal, SIGKILL);
1847 signal_wake_up(t, 1);
1848 nr++;
1849 }
1850 } while_each_thread(start, t);
1851
1852 return nr;
1853}
1854
1855static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1856 struct core_state *core_state, int exit_code)
1857{
1858 struct task_struct *g, *p;
1859 unsigned long flags;
1860 int nr = -EAGAIN;
1861
1862 spin_lock_irq(&tsk->sighand->siglock);
1863 if (!signal_group_exit(tsk->signal)) {
1864 mm->core_state = core_state;
1865 nr = zap_process(tsk, exit_code);
1866 }
1867 spin_unlock_irq(&tsk->sighand->siglock);
1868 if (unlikely(nr < 0))
1869 return nr;
1870
1871 if (atomic_read(&mm->mm_users) == nr + 1)
1872 goto done;
1873 /*
1874 * We should find and kill all tasks which use this mm, and we should
1875 * count them correctly into ->nr_threads. We don't take tasklist
1876 * lock, but this is safe wrt:
1877 *
1878 * fork:
1879 * None of sub-threads can fork after zap_process(leader). All
1880 * processes which were created before this point should be
1881 * visible to zap_threads() because copy_process() adds the new
1882 * process to the tail of init_task.tasks list, and lock/unlock
1883 * of ->siglock provides a memory barrier.
1884 *
1885 * do_exit:
1886 * The caller holds mm->mmap_sem. This means that the task which
1887 * uses this mm can't pass exit_mm(), so it can't exit or clear
1888 * its ->mm.
1889 *
1890 * de_thread:
1891 * It does list_replace_rcu(&leader->tasks, &current->tasks),
1892 * we must see either old or new leader, this does not matter.
1893 * However, it can change p->sighand, so lock_task_sighand(p)
1894 * must be used. Since p->mm != NULL and we hold ->mmap_sem
1895 * it can't fail.
1896 *
1897 * Note also that "g" can be the old leader with ->mm == NULL
1898 * and already unhashed and thus removed from ->thread_group.
1899 * This is OK, __unhash_process()->list_del_rcu() does not
1900 * clear the ->next pointer, we will find the new leader via
1901 * next_thread().
1902 */
1903 rcu_read_lock();
1904 for_each_process(g) {
1905 if (g == tsk->group_leader)
1906 continue;
1907 if (g->flags & PF_KTHREAD)
1908 continue;
1909 p = g;
1910 do {
1911 if (p->mm) {
1912 if (unlikely(p->mm == mm)) {
1913 lock_task_sighand(p, &flags);
1914 nr += zap_process(p, exit_code);
1915 unlock_task_sighand(p, &flags);
1916 }
1917 break;
1918 }
1919 } while_each_thread(g, p);
1920 }
1921 rcu_read_unlock();
1922done:
1923 atomic_set(&core_state->nr_threads, nr);
1924 return nr;
1925}
1926
1927static int coredump_wait(int exit_code, struct core_state *core_state)
1928{
1929 struct task_struct *tsk = current;
1930 struct mm_struct *mm = tsk->mm;
1931 int core_waiters = -EBUSY;
1932
1933 init_completion(&core_state->startup);
1934 core_state->dumper.task = tsk;
1935 core_state->dumper.next = NULL;
1936
1937 down_write(&mm->mmap_sem);
1938 if (!mm->core_state)
1939 core_waiters = zap_threads(tsk, mm, core_state, exit_code);
1940 up_write(&mm->mmap_sem);
1941
1942 if (core_waiters > 0) {
1943 struct core_thread *ptr;
1944
1945 wait_for_completion(&core_state->startup);
1946 /*
1947 * Wait for all the threads to become inactive, so that
1948 * all the thread context (extended register state, like
1949 * fpu etc) gets copied to the memory.
1950 */
1951 ptr = core_state->dumper.next;
1952 while (ptr != NULL) {
1953 wait_task_inactive(ptr->task, 0);
1954 ptr = ptr->next;
1955 }
1956 }
1957
1958 return core_waiters;
1959}
1960
1961static void coredump_finish(struct mm_struct *mm)
1962{
1963 struct core_thread *curr, *next;
1964 struct task_struct *task;
1965
1966 next = mm->core_state->dumper.next;
1967 while ((curr = next) != NULL) {
1968 next = curr->next;
1969 task = curr->task;
1970 /*
1971 * see exit_mm(), curr->task must not see
1972 * ->task == NULL before we read ->next.
1973 */
1974 smp_mb();
1975 curr->task = NULL;
1976 wake_up_process(task);
1977 }
1978
1979 mm->core_state = NULL;
1980}
1981
1982/* 1595/*
1983 * set_dumpable converts traditional three-value dumpable to two flags and 1596 * set_dumpable converts traditional three-value dumpable to two flags and
1984 * stores them into mm->flags. It modifies lower two bits of mm->flags, but 1597 * stores them into mm->flags. It modifies lower two bits of mm->flags, but
@@ -2020,7 +1633,7 @@ void set_dumpable(struct mm_struct *mm, int value)
2020 } 1633 }
2021} 1634}
2022 1635
2023static int __get_dumpable(unsigned long mm_flags) 1636int __get_dumpable(unsigned long mm_flags)
2024{ 1637{
2025 int ret; 1638 int ret;
2026 1639
@@ -2032,290 +1645,3 @@ int get_dumpable(struct mm_struct *mm)
2032{ 1645{
2033 return __get_dumpable(mm->flags); 1646 return __get_dumpable(mm->flags);
2034} 1647}
2035
2036static void wait_for_dump_helpers(struct file *file)
2037{
2038 struct pipe_inode_info *pipe;
2039
2040 pipe = file->f_path.dentry->d_inode->i_pipe;
2041
2042 pipe_lock(pipe);
2043 pipe->readers++;
2044 pipe->writers--;
2045
2046 while ((pipe->readers > 1) && (!signal_pending(current))) {
2047 wake_up_interruptible_sync(&pipe->wait);
2048 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
2049 pipe_wait(pipe);
2050 }
2051
2052 pipe->readers--;
2053 pipe->writers++;
2054 pipe_unlock(pipe);
2055
2056}
2057
2058
2059/*
2060 * umh_pipe_setup
2061 * helper function to customize the process used
2062 * to collect the core in userspace. Specifically
2063 * it sets up a pipe and installs it as fd 0 (stdin)
2064 * for the process. Returns 0 on success, or
2065 * PTR_ERR on failure.
2066 * Note that it also sets the core limit to 1. This
2067 * is a special value that we use to trap recursive
2068 * core dumps
2069 */
2070static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
2071{
2072 struct file *files[2];
2073 struct fdtable *fdt;
2074 struct coredump_params *cp = (struct coredump_params *)info->data;
2075 struct files_struct *cf = current->files;
2076 int err = create_pipe_files(files, 0);
2077 if (err)
2078 return err;
2079
2080 cp->file = files[1];
2081
2082 sys_close(0);
2083 fd_install(0, files[0]);
2084 spin_lock(&cf->file_lock);
2085 fdt = files_fdtable(cf);
2086 __set_open_fd(0, fdt);
2087 __clear_close_on_exec(0, fdt);
2088 spin_unlock(&cf->file_lock);
2089
2090 /* and disallow core files too */
2091 current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
2092
2093 return 0;
2094}
2095
2096void do_coredump(long signr, int exit_code, struct pt_regs *regs)
2097{
2098 struct core_state core_state;
2099 struct core_name cn;
2100 struct mm_struct *mm = current->mm;
2101 struct linux_binfmt * binfmt;
2102 const struct cred *old_cred;
2103 struct cred *cred;
2104 int retval = 0;
2105 int flag = 0;
2106 int ispipe;
2107 bool need_nonrelative = false;
2108 static atomic_t core_dump_count = ATOMIC_INIT(0);
2109 struct coredump_params cprm = {
2110 .signr = signr,
2111 .regs = regs,
2112 .limit = rlimit(RLIMIT_CORE),
2113 /*
2114 * We must use the same mm->flags while dumping core to avoid
2115 * inconsistency of bit flags, since this flag is not protected
2116 * by any locks.
2117 */
2118 .mm_flags = mm->flags,
2119 };
2120
2121 audit_core_dumps(signr);
2122
2123 binfmt = mm->binfmt;
2124 if (!binfmt || !binfmt->core_dump)
2125 goto fail;
2126 if (!__get_dumpable(cprm.mm_flags))
2127 goto fail;
2128
2129 cred = prepare_creds();
2130 if (!cred)
2131 goto fail;
2132 /*
2133 * We cannot trust fsuid as being the "true" uid of the process
2134 * nor do we know its entire history. We only know it was tainted
2135 * so we dump it as root in mode 2, and only into a controlled
2136 * environment (pipe handler or fully qualified path).
2137 */
2138 if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) {
2139 /* Setuid core dump mode */
2140 flag = O_EXCL; /* Stop rewrite attacks */
2141 cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */
2142 need_nonrelative = true;
2143 }
2144
2145 retval = coredump_wait(exit_code, &core_state);
2146 if (retval < 0)
2147 goto fail_creds;
2148
2149 old_cred = override_creds(cred);
2150
2151 /*
2152 * Clear any false indication of pending signals that might
2153 * be seen by the filesystem code called to write the core file.
2154 */
2155 clear_thread_flag(TIF_SIGPENDING);
2156
2157 ispipe = format_corename(&cn, signr);
2158
2159 if (ispipe) {
2160 int dump_count;
2161 char **helper_argv;
2162
2163 if (ispipe < 0) {
2164 printk(KERN_WARNING "format_corename failed\n");
2165 printk(KERN_WARNING "Aborting core\n");
2166 goto fail_corename;
2167 }
2168
2169 if (cprm.limit == 1) {
2170 /* See umh_pipe_setup() which sets RLIMIT_CORE = 1.
2171 *
2172 * Normally core limits are irrelevant to pipes, since
2173 * we're not writing to the file system, but we use
2174 * cprm.limit of 1 here as a speacial value, this is a
2175 * consistent way to catch recursive crashes.
2176 * We can still crash if the core_pattern binary sets
2177 * RLIM_CORE = !1, but it runs as root, and can do
2178 * lots of stupid things.
2179 *
2180 * Note that we use task_tgid_vnr here to grab the pid
2181 * of the process group leader. That way we get the
2182 * right pid if a thread in a multi-threaded
2183 * core_pattern process dies.
2184 */
2185 printk(KERN_WARNING
2186 "Process %d(%s) has RLIMIT_CORE set to 1\n",
2187 task_tgid_vnr(current), current->comm);
2188 printk(KERN_WARNING "Aborting core\n");
2189 goto fail_unlock;
2190 }
2191 cprm.limit = RLIM_INFINITY;
2192
2193 dump_count = atomic_inc_return(&core_dump_count);
2194 if (core_pipe_limit && (core_pipe_limit < dump_count)) {
2195 printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n",
2196 task_tgid_vnr(current), current->comm);
2197 printk(KERN_WARNING "Skipping core dump\n");
2198 goto fail_dropcount;
2199 }
2200
2201 helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
2202 if (!helper_argv) {
2203 printk(KERN_WARNING "%s failed to allocate memory\n",
2204 __func__);
2205 goto fail_dropcount;
2206 }
2207
2208 retval = call_usermodehelper_fns(helper_argv[0], helper_argv,
2209 NULL, UMH_WAIT_EXEC, umh_pipe_setup,
2210 NULL, &cprm);
2211 argv_free(helper_argv);
2212 if (retval) {
2213 printk(KERN_INFO "Core dump to %s pipe failed\n",
2214 cn.corename);
2215 goto close_fail;
2216 }
2217 } else {
2218 struct inode *inode;
2219
2220 if (cprm.limit < binfmt->min_coredump)
2221 goto fail_unlock;
2222
2223 if (need_nonrelative && cn.corename[0] != '/') {
2224 printk(KERN_WARNING "Pid %d(%s) can only dump core "\
2225 "to fully qualified path!\n",
2226 task_tgid_vnr(current), current->comm);
2227 printk(KERN_WARNING "Skipping core dump\n");
2228 goto fail_unlock;
2229 }
2230
2231 cprm.file = filp_open(cn.corename,
2232 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
2233 0600);
2234 if (IS_ERR(cprm.file))
2235 goto fail_unlock;
2236
2237 inode = cprm.file->f_path.dentry->d_inode;
2238 if (inode->i_nlink > 1)
2239 goto close_fail;
2240 if (d_unhashed(cprm.file->f_path.dentry))
2241 goto close_fail;
2242 /*
2243 * AK: actually i see no reason to not allow this for named
2244 * pipes etc, but keep the previous behaviour for now.
2245 */
2246 if (!S_ISREG(inode->i_mode))
2247 goto close_fail;
2248 /*
2249 * Dont allow local users get cute and trick others to coredump
2250 * into their pre-created files.
2251 */
2252 if (!uid_eq(inode->i_uid, current_fsuid()))
2253 goto close_fail;
2254 if (!cprm.file->f_op || !cprm.file->f_op->write)
2255 goto close_fail;
2256 if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
2257 goto close_fail;
2258 }
2259
2260 retval = binfmt->core_dump(&cprm);
2261 if (retval)
2262 current->signal->group_exit_code |= 0x80;
2263
2264 if (ispipe && core_pipe_limit)
2265 wait_for_dump_helpers(cprm.file);
2266close_fail:
2267 if (cprm.file)
2268 filp_close(cprm.file, NULL);
2269fail_dropcount:
2270 if (ispipe)
2271 atomic_dec(&core_dump_count);
2272fail_unlock:
2273 kfree(cn.corename);
2274fail_corename:
2275 coredump_finish(mm);
2276 revert_creds(old_cred);
2277fail_creds:
2278 put_cred(cred);
2279fail:
2280 return;
2281}
2282
2283/*
2284 * Core dumping helper functions. These are the only things you should
2285 * do on a core-file: use only these functions to write out all the
2286 * necessary info.
2287 */
2288int dump_write(struct file *file, const void *addr, int nr)
2289{
2290 return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr;
2291}
2292EXPORT_SYMBOL(dump_write);
2293
2294int dump_seek(struct file *file, loff_t off)
2295{
2296 int ret = 1;
2297
2298 if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
2299 if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
2300 return 0;
2301 } else {
2302 char *buf = (char *)get_zeroed_page(GFP_KERNEL);
2303
2304 if (!buf)
2305 return 0;
2306 while (off > 0) {
2307 unsigned long n = off;
2308
2309 if (n > PAGE_SIZE)
2310 n = PAGE_SIZE;
2311 if (!dump_write(file, buf, n)) {
2312 ret = 0;
2313 break;
2314 }
2315 off -= n;
2316 }
2317 free_page((unsigned long)buf);
2318 }
2319 return ret;
2320}
2321EXPORT_SYMBOL(dump_seek);