Merge master.kernel.org:/home/rmk/linux-2.6-mmc

[linux-2.6-omap-h63xx.git] / arch / um / os-Linux / mem.c

diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index 6ab372da96579e4a49e372b920ff302d703484f2..c6432e7292411de1ea2006aabf97a13c3a7fa4eb 100644 (file)
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -8,6 +8,7 @@
 #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"
@@ -19,6 +20,7 @@
 
 #include <sys/param.h>
 
+static char *default_tmpdir = "/tmp";
 static char *tempdir = NULL;
 
 static void __init find_tempdir(void)
@@ -34,7 +36,7 @@ static void __init find_tempdir(void)
                        break;
        }
        if((dir == NULL) || (*dir == '\0'))
-               dir = "/tmp";
+               dir = default_tmpdir;
 
        tempdir = malloc(strlen(dir) + 2);
        if(tempdir == NULL){
@@ -46,6 +48,96 @@ static void __init find_tempdir(void)
        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;
+       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++;
+       memmove(buf, ptr, strlen(ptr) + 1);
+       return 1;
+}
+
+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, sizeof(buf) / sizeof(buf[0]), ' ');
+               if(found != 1)
+                       break;
+
+               if(!strncmp(buf, "/dev/shm", strlen("/dev/shm")))
+                       goto found;
+
+               found = next(fd, buf, sizeof(buf) / sizeof(buf[0]), '\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);
+
+       return;
+
+found:
+       found = next(fd, buf, sizeof(buf) / sizeof(buf[0]), ' ');
+       if(found != 1)
+               goto err;
+
+       if(strncmp(buf, "tmpfs", strlen("tmpfs"))){
+               printf("not tmpfs\n");
+               return;
+       }
+
+       printf("OK\n");
+       default_tmpdir = "/dev/shm";
+}
+
 /*
  * This proc still used in tt-mode
  * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger).
@@ -53,33 +145,37 @@ static void __init find_tempdir(void)
  */
 int make_tempfile(const char *template, char **out_tempname, int do_unlink)
 {
-       char tempname[MAXPATHLEN];
+       char *tempname;
        int fd;
 
+       which_tmpdir();
+       tempname = malloc(MAXPATHLEN);
+
        find_tempdir();
-       if (*template != '/')
+       if (template[0] != '/')
                strcpy(tempname, tempdir);
        else
-               *tempname = 0;
+               tempname[0] = '\0';
        strcat(tempname, template);
        fd = mkstemp(tempname);
        if(fd < 0){
                fprintf(stderr, "open - cannot create %s: %s\n", tempname,
                        strerror(errno));
-               return -1;
+               goto out;
        }
        if(do_unlink && (unlink(tempname) < 0)){
                perror("unlink");
-               return -1;
+               goto out;
        }
        if(out_tempname){
-               *out_tempname = strdup(tempname);
-               if(*out_tempname == NULL){
-                       perror("strdup");
-                       return -1;
-               }
+               *out_tempname = tempname;
+       } else {
+               free(tempname);
        }
        return(fd);
+out:
+       free(tempname);
+       return -1;
 }
 
 #define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
@@ -134,3 +230,26 @@ int create_mem_file(unsigned long long len)
        }
        return(fd);
 }
+
+
+void 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);
+}