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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
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…/git/rw/uml

Pull UML fixes from Richard Weinberger:
 "Special thanks goes to Toralf Föster for continuously testing UML and
  reporting issues!"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: remove dead code
  um: siginfo cleanup
  uml: Fix which_tmpdir failure when /dev/shm is a symlink, and in other edge cases
  um: Fix wait_stub_done() error handling
  um: Mark stub pages mapping with VM_PFNMAP
  um: Fix return value of strnlen_user()
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@torvalds
torvalds committed Jul 19, 2013
2 parents 1b05018 + 9e82d45 commit d471ce5
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Showing 8 changed files with 213 additions and 61 deletions.
8 changes: 4 additions & 4 deletions arch/um/include/shared/frame_kern.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,13 @@
#ifndef __FRAME_KERN_H_
#define __FRAME_KERN_H_

extern int setup_signal_stack_sc(unsigned long stack_top, int sig,
extern int setup_signal_stack_sc(unsigned long stack_top, int sig,
struct k_sigaction *ka,
struct pt_regs *regs,
struct pt_regs *regs,
sigset_t *mask);
extern int setup_signal_stack_si(unsigned long stack_top, int sig,
extern int setup_signal_stack_si(unsigned long stack_top, int sig,
struct k_sigaction *ka,
struct pt_regs *regs, siginfo_t *info,
struct pt_regs *regs, struct siginfo *info,
sigset_t *mask);

#endif
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4 changes: 2 additions & 2 deletions arch/um/kernel/signal.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ EXPORT_SYMBOL(unblock_signals);
* OK, we're invoking a handler
*/
static void handle_signal(struct pt_regs *regs, unsigned long signr,
struct k_sigaction *ka, siginfo_t *info)
struct k_sigaction *ka, struct siginfo *info)
{
sigset_t *oldset = sigmask_to_save();
int singlestep = 0;
Expand Down Expand Up @@ -71,7 +71,7 @@ static void handle_signal(struct pt_regs *regs, unsigned long signr,
static int kern_do_signal(struct pt_regs *regs)
{
struct k_sigaction ka_copy;
siginfo_t info;
struct siginfo info;
int sig, handled_sig = 0;

while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
Expand Down
2 changes: 1 addition & 1 deletion arch/um/kernel/skas/mmu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -123,7 +123,7 @@ void uml_setup_stubs(struct mm_struct *mm)
/* dup_mmap already holds mmap_sem */
err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
VM_READ | VM_MAYREAD | VM_EXEC |
VM_MAYEXEC | VM_DONTCOPY,
VM_MAYEXEC | VM_DONTCOPY | VM_PFNMAP,
mm->context.stub_pages);
if (err) {
printk(KERN_ERR "install_special_mapping returned %d\n", err);
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2 changes: 1 addition & 1 deletion arch/um/kernel/skas/uaccess.c
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Original file line number Diff line number Diff line change
Expand Up @@ -254,6 +254,6 @@ int strnlen_user(const void __user *str, int len)
n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
if (n == 0)
return count + 1;
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(strnlen_user);
230 changes: 189 additions & 41 deletions arch/um/os-Linux/mem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,25 @@ static void __init find_tempdir(void)
strcat(tempdir, "/");
}

/*
* Remove bytes from the front of the buffer and refill it so that if there's a
* partial string that we care about, it will be completed, and we can recognize
* it.
*/
static int pop(int fd, char *buf, size_t size, size_t npop)
{
ssize_t n;
size_t len = strlen(&buf[npop]);

memmove(buf, &buf[npop], len + 1);
n = read(fd, &buf[len], size - len - 1);
if (n < 0)
return -errno;

buf[len + n] = '\0';
return 1;
}

/*
* This will return 1, with the first character in buf being the
* character following the next instance of c in the file. This will
Expand All @@ -61,7 +80,6 @@ static void __init find_tempdir(void)
static int next(int fd, char *buf, size_t size, char c)
{
ssize_t n;
size_t len;
char *ptr;

while ((ptr = strchr(buf, c)) == NULL) {
Expand All @@ -74,20 +92,129 @@ static int next(int fd, char *buf, size_t size, char c)
buf[n] = '\0';
}

ptr++;
len = strlen(ptr);
memmove(buf, ptr, len + 1);
return pop(fd, buf, size, ptr - buf + 1);
}

/*
* Decode an octal-escaped and space-terminated path of the form used by
* /proc/mounts. May be used to decode a path in-place. "out" must be at least
* as large as the input. The output is always null-terminated. "len" gets the
* length of the output, excluding the trailing null. Returns 0 if a full path
* was successfully decoded, otherwise an error.
*/
static int decode_path(const char *in, char *out, size_t *len)
{
char *first = out;
int c;
int i;
int ret = -EINVAL;
while (1) {
switch (*in) {
case '\0':
goto out;

case ' ':
ret = 0;
goto out;

case '\\':
in++;
c = 0;
for (i = 0; i < 3; i++) {
if (*in < '0' || *in > '7')
goto out;
c = (c << 3) | (*in++ - '0');
}
*(unsigned char *)out++ = (unsigned char) c;
break;

default:
*out++ = *in++;
break;
}
}

out:
*out = '\0';
*len = out - first;
return ret;
}

/*
* Computes the length of s when encoded with three-digit octal escape sequences
* for the characters in chars.
*/
static size_t octal_encoded_length(const char *s, const char *chars)
{
size_t len = strlen(s);
while ((s = strpbrk(s, chars)) != NULL) {
len += 3;
s++;
}

return len;
}

enum {
OUTCOME_NOTHING_MOUNTED,
OUTCOME_TMPFS_MOUNT,
OUTCOME_NON_TMPFS_MOUNT,
};

/* Read a line of /proc/mounts data looking for a tmpfs mount at "path". */
static int read_mount(int fd, char *buf, size_t bufsize, const char *path,
int *outcome)
{
int found;
int match;
char *space;
size_t len;

enum {
MATCH_NONE,
MATCH_EXACT,
MATCH_PARENT,
};

found = next(fd, buf, bufsize, ' ');
if (found != 1)
return found;

/*
* Refill the buffer so that if there's a partial string that we care
* about, it will be completed, and we can recognize it.
* If there's no following space in the buffer, then this path is
* truncated, so it can't be the one we're looking for.
*/
n = read(fd, &buf[len], size - len - 1);
if (n < 0)
return -errno;
space = strchr(buf, ' ');
if (space) {
match = MATCH_NONE;
if (!decode_path(buf, buf, &len)) {
if (!strcmp(buf, path))
match = MATCH_EXACT;
else if (!strncmp(buf, path, len)
&& (path[len] == '/' || !strcmp(buf, "/")))
match = MATCH_PARENT;
}

found = pop(fd, buf, bufsize, space - buf + 1);
if (found != 1)
return found;

switch (match) {
case MATCH_EXACT:
if (!strncmp(buf, "tmpfs", strlen("tmpfs")))
*outcome = OUTCOME_TMPFS_MOUNT;
else
*outcome = OUTCOME_NON_TMPFS_MOUNT;
break;

buf[len + n] = '\0';
return 1;
case MATCH_PARENT:
/* This mount obscures any previous ones. */
*outcome = OUTCOME_NOTHING_MOUNTED;
break;
}
}

return next(fd, buf, bufsize, '\n');
}

/* which_tmpdir is called only during early boot */
Expand All @@ -106,8 +233,12 @@ static int checked_tmpdir = 0;
*/
static void which_tmpdir(void)
{
int fd, found;
char buf[128] = { '\0' };
int fd;
int found;
int outcome;
char *path;
char *buf;
size_t bufsize;

if (checked_tmpdir)
return;
Expand All @@ -116,49 +247,66 @@ static void which_tmpdir(void)

printf("Checking for tmpfs mount on /dev/shm...");

path = realpath("/dev/shm", NULL);
if (!path) {
printf("failed to check real path, errno = %d\n", errno);
return;
}
printf("%s...", path);

/*
* The buffer needs to be able to fit the full octal-escaped path, a
* space, and a trailing null in order to successfully decode it.
*/
bufsize = octal_encoded_length(path, " \t\n\\") + 2;

if (bufsize < 128)
bufsize = 128;

buf = malloc(bufsize);
if (!buf) {
printf("malloc failed, errno = %d\n", errno);
goto out;
}
buf[0] = '\0';

fd = open("/proc/mounts", O_RDONLY);
if (fd < 0) {
printf("failed to open /proc/mounts, errno = %d\n", errno);
return;
goto out1;
}

outcome = OUTCOME_NOTHING_MOUNTED;
while (1) {
found = next(fd, buf, ARRAY_SIZE(buf), ' ');
if (found != 1)
break;

if (!strncmp(buf, "/dev/shm", strlen("/dev/shm")))
goto found;

found = next(fd, buf, ARRAY_SIZE(buf), '\n');
found = read_mount(fd, buf, bufsize, path, &outcome);
if (found != 1)
break;
}

err:
if (found == 0)
printf("nothing mounted on /dev/shm\n");
else if (found < 0)
if (found < 0) {
printf("read returned errno %d\n", -found);
} else {
switch (outcome) {
case OUTCOME_TMPFS_MOUNT:
printf("OK\n");
default_tmpdir = "/dev/shm";
break;

out:
close(fd);

return;

found:
found = next(fd, buf, ARRAY_SIZE(buf), ' ');
if (found != 1)
goto err;
case OUTCOME_NON_TMPFS_MOUNT:
printf("not tmpfs\n");
break;

if (strncmp(buf, "tmpfs", strlen("tmpfs"))) {
printf("not tmpfs\n");
goto out;
default:
printf("nothing mounted on /dev/shm\n");
break;
}
}

printf("OK\n");
default_tmpdir = "/dev/shm";
goto out;
close(fd);
out1:
free(buf);
out:
free(path);
}

static int __init make_tempfile(const char *template, char **out_tempname,
Expand Down
8 changes: 4 additions & 4 deletions arch/um/os-Linux/signal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
[SIGIO] = sigio_handler,
[SIGVTALRM] = timer_handler };

static void sig_handler_common(int sig, siginfo_t *si, mcontext_t *mc)
static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
{
struct uml_pt_regs r;
int save_errno = errno;
Expand Down Expand Up @@ -61,7 +61,7 @@ static void sig_handler_common(int sig, siginfo_t *si, mcontext_t *mc)
static int signals_enabled;
static unsigned int signals_pending;

void sig_handler(int sig, siginfo_t *si, mcontext_t *mc)
void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
{
int enabled;

Expand Down Expand Up @@ -120,7 +120,7 @@ void set_sigstack(void *sig_stack, int size)
panic("enabling signal stack failed, errno = %d\n", errno);
}

static void (*handlers[_NSIG])(int sig, siginfo_t *si, mcontext_t *mc) = {
static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {
[SIGSEGV] = sig_handler,
[SIGBUS] = sig_handler,
[SIGILL] = sig_handler,
Expand Down Expand Up @@ -162,7 +162,7 @@ static void hard_handler(int sig, siginfo_t *si, void *p)
while ((sig = ffs(pending)) != 0){
sig--;
pending &= ~(1 << sig);
(*handlers[sig])(sig, si, mc);
(*handlers[sig])(sig, (struct siginfo *)si, mc);
}

/*
Expand Down
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