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

Browse Source 
Pull UML fixes from Richard Weinberger:
 "Assorted fixes for UML"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Memory corruption on startup
  um: Missing pipe handling
  uml: Simplify tempdir logic.
This commit is contained in:
Linus Torvalds 2014-04-21 10:05:35 -07:00
commit c089b229df
5 changed files with 98 additions and 311 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/um/include/shared/os.h
View File

@ -136,6 +136,7 @@ extern int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg);
extern int os_get_ifname(int fd, char *namebuf);
extern int os_set_slip(int fd);
extern int os_mode_fd(int fd, int mode);
extern int os_fsync_file(int fd);
extern int os_seek_file(int fd, unsigned long long offset);
extern int os_open_file(const char *file, struct openflags flags, int mode);

1
arch/um/kernel/physmem.c
View File

@ -103,6 +103,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
*/
os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
os_fsync_file(physmem_fd);
bootmap_size = init_bootmem(pfn, pfn + delta);
free_bootmem(__pa(reserve_end) + bootmap_size,

6
arch/um/os-Linux/file.c
View File

@ -237,6 +237,12 @@ void os_close_file(int fd)
{
close(fd);
}
int os_fsync_file(int fd)
{
if (fsync(fd) < 0)
return -errno;
return 0;
}
int os_seek_file(int fd, unsigned long long offset)
{

1
arch/um/os-Linux/main.c
View File

@ -151,6 +151,7 @@ int __init main(int argc, char **argv, char **envp)
#endif
do_uml_initcalls();
change_sig(SIGPIPE, 0);
ret = linux_main(argc, argv);
/*

400
arch/um/os-Linux/mem.c
View File

@ -12,337 +12,117 @@
#include <string.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/vfs.h>
#include <linux/magic.h>
#include <init.h>
#include <os.h>
/* Modified by which_tmpdir, which is called during early boot */
static char *default_tmpdir = "/tmp";
/*
* Modified when creating the physical memory file and when checking
* the tmp filesystem for usability, both happening during early boot.
*/
/* Set by make_tempfile() during early boot. */
static char *tempdir = NULL;
static void __init find_tempdir(void)
/* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */
static int __init check_tmpfs(const char *dir)
{
const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
int i;
char *dir = NULL;
struct statfs st;
if (tempdir != NULL)
/* We've already been called */
return;
for (i = 0; dirs[i]; i++) {
dir = getenv(dirs[i]);
if ((dir != NULL) && (*dir != '\0'))
break;
}
if ((dir == NULL) || (*dir == '\0'))
dir = default_tmpdir;
tempdir = malloc(strlen(dir) + 2);
if (tempdir == NULL) {
fprintf(stderr, "Failed to malloc tempdir, "
"errno = %d\n", errno);
return;
}
strcpy(tempdir, dir);
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
* read the file as needed. If there's an error, -errno is returned;
* if the end of the file is reached, 0 is returned.
*/
static int next(int fd, char *buf, size_t size, char c)
{
ssize_t n;
char *ptr;
while ((ptr = strchr(buf, c)) == NULL) {
n = read(fd, buf, size - 1);
if (n == 0)
return 0;
else if (n < 0)
return -errno;
buf[n] = '\0';
}
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;
/*
* 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.
*/
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;
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 */
static int checked_tmpdir = 0;
/*
* Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
* way to do this than to parse /proc/mounts. statfs will return the
* same filesystem magic number and fs id for both /dev and /dev/shm
* when they are both tmpfs, so you can't tell if they are different
* filesystems. Also, there seems to be no other way of finding the
* mount point of a filesystem from within it.
*
* If a /dev/shm tmpfs entry is found, then we switch to using it.
* Otherwise, we stay with the default /tmp.
*/
static void which_tmpdir(void)
{
int fd;
int found;
int outcome;
char *path;
char *buf;
size_t bufsize;
if (checked_tmpdir)
return;
checked_tmpdir = 1;
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);
goto out1;
}
outcome = OUTCOME_NOTHING_MOUNTED;
while (1) {
found = read_mount(fd, buf, bufsize, path, &outcome);
if (found != 1)
break;
}
if (found < 0) {
printf("read returned errno %d\n", -found);
printf("Checking if %s is on tmpfs...", dir);
if (statfs(dir, &st) < 0) {
printf("%s\n", strerror(errno));
} else if (st.f_type != TMPFS_MAGIC) {
printf("no\n");
} else {
switch (outcome) {
case OUTCOME_TMPFS_MOUNT:
printf("OK\n");
default_tmpdir = "/dev/shm";
break;
case OUTCOME_NON_TMPFS_MOUNT:
printf("not tmpfs\n");
break;
default:
printf("nothing mounted on /dev/shm\n");
break;
}
printf("OK\n");
return 0;
}
close(fd);
out1:
free(buf);
out:
free(path);
return -1;
}
static int __init make_tempfile(const char *template, char **out_tempname,
int do_unlink)
/*
* Choose the tempdir to use. We want something on tmpfs so that our memory is
* not subject to the host's vm.dirty_ratio. If a tempdir is specified in the
* environment, we use that even if it's not on tmpfs, but we warn the user.
* Otherwise, we try common tmpfs locations, and if no tmpfs directory is found
* then we fall back to /tmp.
*/
static char * __init choose_tempdir(void)
{
static const char * const vars[] = {
"TMPDIR",
"TMP",
"TEMP",
NULL
};
static const char fallback_dir[] = "/tmp";
static const char * const tmpfs_dirs[] = {
"/dev/shm",
fallback_dir,
NULL
};
int i;
const char *dir;
printf("Checking environment variables for a tempdir...");
for (i = 0; vars[i]; i++) {
dir = getenv(vars[i]);
if ((dir != NULL) && (*dir != '\0')) {
printf("%s\n", dir);
if (check_tmpfs(dir) >= 0)
goto done;
else
goto warn;
}
}
printf("none found\n");
for (i = 0; tmpfs_dirs[i]; i++) {
dir = tmpfs_dirs[i];
if (check_tmpfs(dir) >= 0)
goto done;
}
dir = fallback_dir;
warn:
printf("Warning: tempdir %s is not on tmpfs\n", dir);
done:
/* Make a copy since getenv results may not remain valid forever. */
return strdup(dir);
}
/*
* Create an unlinked tempfile in a suitable tempdir. template must be the
* basename part of the template with a leading '/'.
*/
static int __init make_tempfile(const char *template)
{
char *tempname;
int fd;
which_tmpdir();
tempname = malloc(MAXPATHLEN);
if (tempdir == NULL) {
tempdir = choose_tempdir();
if (tempdir == NULL) {
fprintf(stderr, "Failed to choose tempdir: %s\n",
strerror(errno));
return -1;
}
}
tempname = malloc(strlen(tempdir) + strlen(template) + 1);
if (tempname == NULL)
return -1;
find_tempdir();
if ((tempdir == NULL) || (strlen(tempdir) >= MAXPATHLEN))
goto out;
if (template[0] != '/')
strcpy(tempname, tempdir);
else
tempname[0] = '\0';
strncat(tempname, template, MAXPATHLEN-1-strlen(tempname));
strcpy(tempname, tempdir);
strcat(tempname, template);
fd = mkstemp(tempname);
if (fd < 0) {
fprintf(stderr, "open - cannot create %s: %s\n", tempname,
strerror(errno));
goto out;
}
if (do_unlink && (unlink(tempname) < 0)) {
if (unlink(tempname) < 0) {
perror("unlink");
goto close;
}
if (out_tempname) {
*out_tempname = tempname;
} else
free(tempname);
free(tempname);
return fd;
close:
close(fd);
@ -351,14 +131,14 @@ out:
return -1;
}
#define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
#define TEMPNAME_TEMPLATE "/vm_file-XXXXXX"
static int __init create_tmp_file(unsigned long long len)
{
int fd, err;
char zero;
fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
fd = make_tempfile(TEMPNAME_TEMPLATE);
if (fd < 0)
exit(1);
@ -402,7 +182,6 @@ int __init create_mem_file(unsigned long long len)
return fd;
}
void __init check_tmpexec(void)
{
void *addr;
@ -410,14 +189,13 @@ void __init check_tmpexec(void)
addr = mmap(NULL, UM_KERN_PAGE_SIZE,
PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
printf("Checking PROT_EXEC mmap in %s...",tempdir);
fflush(stdout);
printf("Checking PROT_EXEC mmap in %s...", tempdir);
if (addr == MAP_FAILED) {
err = errno;
perror("failed");
printf("%s\n", strerror(err));
close(fd);
if (err == EPERM)
printf("%s must be not mounted noexec\n",tempdir);
printf("%s must be not mounted noexec\n", tempdir);
exit(1);
}
printf("OK\n");