Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml
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
commit
c089b229df
5 changed files with 98 additions and 311 deletions
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@ -136,6 +136,7 @@ extern int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg);
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extern int os_get_ifname(int fd, char *namebuf);
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extern int os_set_slip(int fd);
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extern int os_mode_fd(int fd, int mode);
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extern int os_fsync_file(int fd);
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extern int os_seek_file(int fd, unsigned long long offset);
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extern int os_open_file(const char *file, struct openflags flags, int mode);
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@ -103,6 +103,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
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*/
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os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
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os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
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os_fsync_file(physmem_fd);
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bootmap_size = init_bootmem(pfn, pfn + delta);
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free_bootmem(__pa(reserve_end) + bootmap_size,
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@ -237,6 +237,12 @@ void os_close_file(int fd)
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{
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close(fd);
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}
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int os_fsync_file(int fd)
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{
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if (fsync(fd) < 0)
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return -errno;
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return 0;
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}
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int os_seek_file(int fd, unsigned long long offset)
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{
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@ -151,6 +151,7 @@ int __init main(int argc, char **argv, char **envp)
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#endif
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do_uml_initcalls();
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change_sig(SIGPIPE, 0);
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ret = linux_main(argc, argv);
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/*
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@ -12,337 +12,117 @@
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/vfs.h>
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#include <linux/magic.h>
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#include <init.h>
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#include <os.h>
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/* Modified by which_tmpdir, which is called during early boot */
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static char *default_tmpdir = "/tmp";
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/*
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* Modified when creating the physical memory file and when checking
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* the tmp filesystem for usability, both happening during early boot.
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*/
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/* Set by make_tempfile() during early boot. */
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static char *tempdir = NULL;
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static void __init find_tempdir(void)
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/* Check if dir is on tmpfs. Return 0 if yes, -1 if no or error. */
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static int __init check_tmpfs(const char *dir)
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{
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const char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
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int i;
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char *dir = NULL;
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struct statfs st;
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if (tempdir != NULL)
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/* We've already been called */
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return;
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for (i = 0; dirs[i]; i++) {
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dir = getenv(dirs[i]);
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if ((dir != NULL) && (*dir != '\0'))
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break;
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}
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if ((dir == NULL) || (*dir == '\0'))
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dir = default_tmpdir;
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tempdir = malloc(strlen(dir) + 2);
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if (tempdir == NULL) {
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fprintf(stderr, "Failed to malloc tempdir, "
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"errno = %d\n", errno);
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return;
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}
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strcpy(tempdir, dir);
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strcat(tempdir, "/");
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}
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/*
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* Remove bytes from the front of the buffer and refill it so that if there's a
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* partial string that we care about, it will be completed, and we can recognize
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* it.
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*/
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static int pop(int fd, char *buf, size_t size, size_t npop)
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{
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ssize_t n;
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size_t len = strlen(&buf[npop]);
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memmove(buf, &buf[npop], len + 1);
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n = read(fd, &buf[len], size - len - 1);
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if (n < 0)
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return -errno;
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buf[len + n] = '\0';
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return 1;
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}
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/*
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* This will return 1, with the first character in buf being the
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* character following the next instance of c in the file. This will
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* read the file as needed. If there's an error, -errno is returned;
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* if the end of the file is reached, 0 is returned.
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*/
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static int next(int fd, char *buf, size_t size, char c)
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{
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ssize_t n;
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char *ptr;
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while ((ptr = strchr(buf, c)) == NULL) {
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n = read(fd, buf, size - 1);
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if (n == 0)
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return 0;
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else if (n < 0)
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return -errno;
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buf[n] = '\0';
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}
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return pop(fd, buf, size, ptr - buf + 1);
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}
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/*
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* Decode an octal-escaped and space-terminated path of the form used by
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* /proc/mounts. May be used to decode a path in-place. "out" must be at least
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* as large as the input. The output is always null-terminated. "len" gets the
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* length of the output, excluding the trailing null. Returns 0 if a full path
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* was successfully decoded, otherwise an error.
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*/
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static int decode_path(const char *in, char *out, size_t *len)
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{
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char *first = out;
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int c;
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int i;
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int ret = -EINVAL;
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while (1) {
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switch (*in) {
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case '\0':
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goto out;
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case ' ':
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ret = 0;
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goto out;
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case '\\':
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in++;
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c = 0;
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for (i = 0; i < 3; i++) {
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if (*in < '0' || *in > '7')
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goto out;
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c = (c << 3) | (*in++ - '0');
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}
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*(unsigned char *)out++ = (unsigned char) c;
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break;
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default:
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*out++ = *in++;
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break;
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}
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}
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out:
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*out = '\0';
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*len = out - first;
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return ret;
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}
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/*
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* Computes the length of s when encoded with three-digit octal escape sequences
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* for the characters in chars.
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*/
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static size_t octal_encoded_length(const char *s, const char *chars)
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{
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size_t len = strlen(s);
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while ((s = strpbrk(s, chars)) != NULL) {
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len += 3;
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s++;
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}
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return len;
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}
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enum {
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OUTCOME_NOTHING_MOUNTED,
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OUTCOME_TMPFS_MOUNT,
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OUTCOME_NON_TMPFS_MOUNT,
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};
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/* Read a line of /proc/mounts data looking for a tmpfs mount at "path". */
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static int read_mount(int fd, char *buf, size_t bufsize, const char *path,
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int *outcome)
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{
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int found;
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int match;
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char *space;
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size_t len;
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enum {
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MATCH_NONE,
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MATCH_EXACT,
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MATCH_PARENT,
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};
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found = next(fd, buf, bufsize, ' ');
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if (found != 1)
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return found;
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/*
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* If there's no following space in the buffer, then this path is
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* truncated, so it can't be the one we're looking for.
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*/
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space = strchr(buf, ' ');
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if (space) {
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match = MATCH_NONE;
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if (!decode_path(buf, buf, &len)) {
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if (!strcmp(buf, path))
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match = MATCH_EXACT;
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else if (!strncmp(buf, path, len)
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&& (path[len] == '/' || !strcmp(buf, "/")))
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match = MATCH_PARENT;
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}
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found = pop(fd, buf, bufsize, space - buf + 1);
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if (found != 1)
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return found;
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switch (match) {
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case MATCH_EXACT:
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if (!strncmp(buf, "tmpfs", strlen("tmpfs")))
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*outcome = OUTCOME_TMPFS_MOUNT;
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else
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*outcome = OUTCOME_NON_TMPFS_MOUNT;
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break;
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case MATCH_PARENT:
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/* This mount obscures any previous ones. */
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*outcome = OUTCOME_NOTHING_MOUNTED;
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break;
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}
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}
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return next(fd, buf, bufsize, '\n');
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}
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/* which_tmpdir is called only during early boot */
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static int checked_tmpdir = 0;
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/*
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* Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
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* way to do this than to parse /proc/mounts. statfs will return the
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* same filesystem magic number and fs id for both /dev and /dev/shm
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* when they are both tmpfs, so you can't tell if they are different
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* filesystems. Also, there seems to be no other way of finding the
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* mount point of a filesystem from within it.
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*
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* If a /dev/shm tmpfs entry is found, then we switch to using it.
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* Otherwise, we stay with the default /tmp.
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*/
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static void which_tmpdir(void)
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{
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int fd;
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int found;
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int outcome;
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char *path;
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char *buf;
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size_t bufsize;
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if (checked_tmpdir)
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return;
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checked_tmpdir = 1;
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printf("Checking for tmpfs mount on /dev/shm...");
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path = realpath("/dev/shm", NULL);
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if (!path) {
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printf("failed to check real path, errno = %d\n", errno);
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return;
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}
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printf("%s...", path);
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/*
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* The buffer needs to be able to fit the full octal-escaped path, a
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* space, and a trailing null in order to successfully decode it.
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*/
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bufsize = octal_encoded_length(path, " \t\n\\") + 2;
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if (bufsize < 128)
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bufsize = 128;
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buf = malloc(bufsize);
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if (!buf) {
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printf("malloc failed, errno = %d\n", errno);
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goto out;
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}
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buf[0] = '\0';
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fd = open("/proc/mounts", O_RDONLY);
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if (fd < 0) {
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printf("failed to open /proc/mounts, errno = %d\n", errno);
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goto out1;
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}
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outcome = OUTCOME_NOTHING_MOUNTED;
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while (1) {
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found = read_mount(fd, buf, bufsize, path, &outcome);
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if (found != 1)
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break;
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}
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if (found < 0) {
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printf("read returned errno %d\n", -found);
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printf("Checking if %s is on tmpfs...", dir);
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if (statfs(dir, &st) < 0) {
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printf("%s\n", strerror(errno));
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} else if (st.f_type != TMPFS_MAGIC) {
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printf("no\n");
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} else {
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switch (outcome) {
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case OUTCOME_TMPFS_MOUNT:
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printf("OK\n");
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default_tmpdir = "/dev/shm";
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break;
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case OUTCOME_NON_TMPFS_MOUNT:
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printf("not tmpfs\n");
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break;
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default:
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printf("nothing mounted on /dev/shm\n");
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break;
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}
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printf("OK\n");
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return 0;
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}
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close(fd);
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out1:
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free(buf);
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out:
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free(path);
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return -1;
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}
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static int __init make_tempfile(const char *template, char **out_tempname,
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int do_unlink)
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/*
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* Choose the tempdir to use. We want something on tmpfs so that our memory is
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* not subject to the host's vm.dirty_ratio. If a tempdir is specified in the
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* environment, we use that even if it's not on tmpfs, but we warn the user.
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||||
* Otherwise, we try common tmpfs locations, and if no tmpfs directory is found
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* then we fall back to /tmp.
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||||
*/
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||||
static char * __init choose_tempdir(void)
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||||
{
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||||
static const char * const vars[] = {
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"TMPDIR",
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||||
"TMP",
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||||
"TEMP",
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NULL
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||||
};
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||||
static const char fallback_dir[] = "/tmp";
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||||
static const char * const tmpfs_dirs[] = {
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"/dev/shm",
|
||||
fallback_dir,
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NULL
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||||
};
|
||||
int i;
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||||
const char *dir;
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||||
|
||||
printf("Checking environment variables for a tempdir...");
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||||
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. */
|
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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 @@ static int __init make_tempfile(const char *template, char **out_tempname,
|
|||
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");
|
||||
|
|
|
|||
Loading…
Reference in a new issue