arch/um/os-Linux/mem.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <stddef.h>
   4 #include <stdarg.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <fcntl.h>
   9 #include <sys/types.h>
  10 #include <sys/mman.h>
  11 #include "kern_util.h"
  12 #include "user.h"
  13 #include "user_util.h"
  14 #include "mem_user.h"
  15 #include "init.h"
  16 #include "os.h"
  17 #include "tempfile.h"
  18 #include "kern_constants.h"
  19
  20 #include <sys/param.h>
  21
  22 static char *tempdir = NULL;
  23
  24 static void __init find_tempdir(void)
  25 {
  26         char *dirs[] = { "TMP", "TEMP", "TMPDIR", NULL };
  27         int i;
  28         char *dir = NULL;
  29
  30         if(tempdir != NULL) return;     /* We've already been called */
  31         for(i = 0; dirs[i]; i++){
  32                 dir = getenv(dirs[i]);
  33                 if((dir != NULL) && (*dir != '\0'))
  34                         break;
  35         }
  36         if((dir == NULL) || (*dir == '\0'))
  37                 dir = "/tmp";
  38
  39         tempdir = malloc(strlen(dir) + 2);
  40         if(tempdir == NULL){
  41                 fprintf(stderr, "Failed to malloc tempdir, "
  42                         "errno = %d\n", errno);
  43                 return;
  44         }
  45         strcpy(tempdir, dir);
  46         strcat(tempdir, "/");
  47 }
  48
  49 /*
  50  * This proc still used in tt-mode
  51  * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger).
  52  * So it isn't 'static' yet.
  53  */
  54 int make_tempfile(const char *template, char **out_tempname, int do_unlink)
  55 {
  56         char tempname[MAXPATHLEN];
  57         int fd;
  58
  59         find_tempdir();
  60         if (*template != '/')
  61                 strcpy(tempname, tempdir);
  62         else
  63                 *tempname = 0;
  64         strcat(tempname, template);
  65         fd = mkstemp(tempname);
  66         if(fd < 0){
  67                 fprintf(stderr, "open - cannot create %s: %s\n", tempname,
  68                         strerror(errno));
  69                 return -1;
  70         }
  71         if(do_unlink && (unlink(tempname) < 0)){
  72                 perror("unlink");
  73                 return -1;
  74         }
  75         if(out_tempname){
  76                 *out_tempname = strdup(tempname);
  77                 if(*out_tempname == NULL){
  78                         perror("strdup");
  79                         return -1;
  80                 }
  81         }
  82         return(fd);
  83 }
  84
  85 #define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
  86
  87 /*
  88  * This proc is used in start_up.c
  89  * So it isn't 'static'.
  90  */
  91 int create_tmp_file(unsigned long long len)
  92 {
  93         int fd, err;
  94         char zero;
  95
  96         fd = make_tempfile(TEMPNAME_TEMPLATE, NULL, 1);
  97         if(fd < 0) {
  98                 exit(1);
  99         }
 100
 101         err = fchmod(fd, 0777);
 102         if(err < 0){
 103                 perror("os_mode_fd");
 104                 exit(1);
 105         }
 106
 107         if (lseek64(fd, len, SEEK_SET) < 0) {
 108                 perror("os_seek_file");
 109                 exit(1);
 110         }
 111
 112         zero = 0;
 113
 114         err = os_write_file(fd, &zero, 1);
 115         if(err != 1){
 116                 errno = -err;
 117                 perror("os_write_file");
 118                 exit(1);
 119         }
 120
 121         return(fd);
 122 }
 123
 124 static int create_anon_file(unsigned long long len)
 125 {
 126         void *addr;
 127         int fd;
 128
 129         fd = open("/dev/anon", O_RDWR);
 130         if(fd < 0) {
 131                 perror("opening /dev/anon");
 132                 exit(1);
 133         }
 134
 135         addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 136         if(addr == MAP_FAILED){
 137                 perror("mapping physmem file");
 138                 exit(1);
 139         }
 140         munmap(addr, len);
 141
 142         return(fd);
 143 }
 144
 145 extern int have_devanon;
 146
 147 int create_mem_file(unsigned long long len)
 148 {
 149         int err, fd;
 150
 151         if(have_devanon)
 152                 fd = create_anon_file(len);
 153         else fd = create_tmp_file(len);
 154
 155         err = os_set_exec_close(fd, 1);
 156         if(err < 0){
 157                 errno = -err;
 158                 perror("exec_close");
 159         }
 160         return(fd);
 161 }