#include <fcntl.h>
#include <sys/types.h>
#include <sys/mman.h>
+#include <sys/statfs.h>
#include "kern_util.h"
#include "user.h"
-#include "user_util.h"
#include "mem_user.h"
#include "init.h"
#include "os.h"
#include <sys/param.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.
+ */
static char *tempdir = NULL;
static void __init find_tempdir(void)
int i;
char *dir = NULL;
- if(tempdir != NULL) return; /* We've already been called */
+ 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 = "/tmp";
+ dir = default_tmpdir;
tempdir = malloc(strlen(dir) + 2);
if(tempdir == NULL){
strcat(tempdir, "/");
}
+/* 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, int size, char c)
+{
+ int n, len;
+ 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';
+ }
+
+ ptr++;
+ len = strlen(ptr);
+ memmove(buf, ptr, len + 1);
+
+ /* Refill the buffer so that if there's a partial string that we care
+ * about, it will be completed, and we can recognize it.
+ */
+ n = read(fd, &buf[len], size - len - 1);
+ if(n < 0)
+ return -errno;
+
+ buf[len + n] = '\0';
+ return 1;
+}
+
+/* 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, found;
+ char buf[128] = { '\0' };
+
+ if(checked_tmpdir)
+ return;
+
+ checked_tmpdir = 1;
+
+ printf("Checking for tmpfs mount on /dev/shm...");
+
+ fd = open("/proc/mounts", O_RDONLY);
+ if(fd < 0){
+ printf("failed to open /proc/mounts, errno = %d\n", errno);
+ return;
+ }
+
+ 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');
+ if(found != 1)
+ break;
+ }
+
+err:
+ if(found == 0)
+ printf("nothing mounted on /dev/shm\n");
+ else if(found < 0)
+ printf("read returned errno %d\n", -found);
+
+out:
+ close(fd);
+
+ return;
+
+found:
+ found = next(fd, buf, ARRAY_SIZE(buf), ' ');
+ if(found != 1)
+ goto err;
+
+ if(strncmp(buf, "tmpfs", strlen("tmpfs"))){
+ printf("not tmpfs\n");
+ goto out;
+ }
+
+ printf("OK\n");
+ default_tmpdir = "/dev/shm";
+ goto out;
+}
+
/*
* This proc still used in tt-mode
* (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger).
* So it isn't 'static' yet.
*/
-int make_tempfile(const char *template, char **out_tempname, int do_unlink)
+int __init make_tempfile(const char *template, char **out_tempname,
+ int do_unlink)
{
char *tempname;
int fd;
+ which_tmpdir();
tempname = malloc(MAXPATHLEN);
find_tempdir();
} else {
free(tempname);
}
- return(fd);
+ return fd;
out:
free(tempname);
return -1;
* This proc is used in start_up.c
* So it isn't 'static'.
*/
-int create_tmp_file(unsigned long long len)
+int __init create_tmp_file(unsigned long long len)
{
int fd, err;
char zero;
exit(1);
}
- if (lseek64(fd, len, SEEK_SET) < 0) {
- perror("os_seek_file");
+ /* Seek to len - 1 because writing a character there will
+ * increase the file size by one byte, to the desired length.
+ */
+ if (lseek64(fd, len - 1, SEEK_SET) < 0) {
+ perror("os_seek_file");
exit(1);
}
zero = 0;
- err = os_write_file(fd, &zero, 1);
+ err = write(fd, &zero, 1);
if(err != 1){
- errno = -err;
- perror("os_write_file");
+ perror("write");
exit(1);
}
- return(fd);
+ return fd;
}
-int create_mem_file(unsigned long long len)
+int __init create_mem_file(unsigned long long len)
{
int err, fd;
errno = -err;
perror("exec_close");
}
- return(fd);
+ return fd;
+}
+
+
+void __init check_tmpexec(void)
+{
+ void *addr;
+ int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
+
+ 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);
+ if(addr == MAP_FAILED){
+ err = errno;
+ perror("failed");
+ if(err == EPERM)
+ printf("%s must be not mounted noexec\n",tempdir);
+ exit(1);
+ }
+ printf("OK\n");
+ munmap(addr, UM_KERN_PAGE_SIZE);
+
+ close(fd);
}
projects / linux-drm-fsl-dcu.git / blobdiff