minix/servers/rs/exec.c

   1 #include "inc.h"
   2 #include <assert.h>
   3 #include <sys/exec.h>
   4 #include <libexec.h>
   5 #include <machine/vmparam.h>
   6
   7 static int do_exec(int proc_e, char *exec, size_t exec_len, char *progname,
   8         char *frame, int frame_len, vir_bytes ps_str);
   9 static int exec_restart(int proc_e, int result, vir_bytes pc, vir_bytes ps_str);
  10 static int read_seg(struct exec_info *execi, off_t off,
  11         vir_bytes seg_addr, size_t seg_bytes);
  12
  13 /* Array of loaders for different object formats */
  14 static struct exec_loaders {
  15         libexec_exec_loadfunc_t load_object;
  16 } const exec_loaders[] = {
  17         { libexec_load_elf },
  18         { NULL }
  19 };
  20
  21 int srv_execve(int proc_e, char *exec, size_t exec_len, char *progname,
  22         char **argv, char **envp)
  23 {
  24         size_t frame_size = 0;  /* Size of the new initial stack. */
  25         int argc = 0;           /* Argument count. */
  26         int envc = 0;           /* Environment count */
  27         char overflow = 0;      /* No overflow yet. */
  28         char *frame;
  29         struct ps_strings *psp;
  30         int vsp = 0;    /* (virtual) Stack pointer in new address space. */
  31
  32         int r;
  33
  34         minix_stack_params(argv[0], argv, envp, &frame_size, &overflow,
  35                 &argc, &envc);
  36
  37         /* The party is off if there is an overflow. */
  38         if (overflow) {
  39                 errno = E2BIG;
  40                 return -1;
  41         }
  42
  43         /* Allocate space for the stack frame. */
  44         if ((frame = (char *) sbrk(frame_size)) == (char *) -1) {
  45                 errno = E2BIG;
  46                 return -1;
  47         }
  48
  49         minix_stack_fill(argv[0], argc, argv, envc, envp, frame_size, frame,
  50                 &vsp, &psp);
  51
  52         r = do_exec(proc_e, exec, exec_len, progname, frame, frame_size,
  53                 vsp + ((char *)psp - frame));
  54
  55         /* Failure, return the memory used for the frame and exit. */
  56         (void) sbrk(-frame_size);
  57
  58         return r;
  59 }
  60
  61
  62 static int do_exec(int proc_e, char *exec, size_t exec_len, char *progname,
  63         char *frame, int frame_len, vir_bytes ps_str)
  64 {
  65         int r;
  66         vir_bytes vsp;
  67         struct exec_info execi;
  68         int i;
  69
  70         memset(&execi, 0, sizeof(execi));
  71
  72         execi.stack_high = minix_get_user_sp();
  73         execi.stack_size = DEFAULT_STACK_LIMIT;
  74         execi.proc_e = proc_e;
  75         execi.hdr = exec;
  76         execi.filesize = execi.hdr_len = exec_len;
  77         strncpy(execi.progname, progname, PROC_NAME_LEN-1);
  78         execi.progname[PROC_NAME_LEN-1] = '\0';
  79         execi.frame_len = frame_len;
  80
  81         /* callback functions and data */
  82         execi.copymem = read_seg;
  83         execi.clearproc = libexec_clearproc_vm_procctl;
  84         execi.clearmem = libexec_clear_sys_memset;
  85         execi.allocmem_prealloc_cleared = libexec_alloc_mmap_prealloc_cleared;
  86         execi.allocmem_prealloc_junk = libexec_alloc_mmap_prealloc_junk;
  87         execi.allocmem_ondemand = libexec_alloc_mmap_ondemand;
  88
  89         for(i = 0; exec_loaders[i].load_object != NULL; i++) {
  90             r = (*exec_loaders[i].load_object)(&execi);
  91             /* Loaded successfully, so no need to try other loaders */
  92             if (r == OK) break;
  93         }
  94
  95         /* No exec loader could load the object */
  96         if (r != OK) {
  97             printf("RS: do_exec: loading error %d\n", r);
  98             return r;
  99         }
 100
 101         /* Inform PM */
 102         if((r = libexec_pm_newexec(execi.proc_e, &execi)) != OK)
 103                 return r;
 104
 105         /* Patch up stack and copy it from RS to new core image. */
 106         vsp = execi.stack_high - frame_len;
 107         r = sys_datacopy(SELF, (vir_bytes) frame,
 108                 proc_e, (vir_bytes) vsp, (phys_bytes)frame_len);
 109         if (r != OK) {
 110                 printf("do_exec: copying out new stack failed: %d\n", r);
 111                 exec_restart(proc_e, r, execi.pc, ps_str);
 112                 return r;
 113         }
 114
 115         return exec_restart(proc_e, OK, execi.pc, ps_str);
 116 }
 117
 118 /*===========================================================================*
 119  *                              exec_restart                                 *
 120  *===========================================================================*/
 121 static int exec_restart(int proc_e, int result, vir_bytes pc, vir_bytes ps_str)
 122 {
 123         int r;
 124         message m;
 125
 126         memset(&m, 0, sizeof(m));
 127         m.m_type = PM_EXEC_RESTART;
 128         m.m_rs_pm_exec_restart.endpt = proc_e;
 129         m.m_rs_pm_exec_restart.result = result;
 130         m.m_rs_pm_exec_restart.pc = pc;
 131         m.m_rs_pm_exec_restart.ps_str = ps_str;
 132
 133         r = ipc_sendrec(PM_PROC_NR, &m);
 134         if (r != OK)
 135                 return r;
 136
 137         return m.m_type;
 138 }
 139
 140 /*===========================================================================*
 141  *                             read_seg                                     *
 142  *===========================================================================*/
 143 static int read_seg(
 144 struct exec_info *execi,       /* various data needed for exec */
 145 off_t off,                     /* offset in file */
 146 vir_bytes seg_addr,            /* address to load segment */
 147 size_t seg_bytes           /* how much is to be transferred? */
 148 )
 149 {
 150 /*
 151  * The byte count on read is usually smaller than the segment count, because
 152  * a segment is padded out to a click multiple, and the data segment is only
 153  * partially initialized.
 154  */
 155
 156   int r;
 157
 158   if (off+seg_bytes > execi->hdr_len) return ENOEXEC;
 159   if((r= sys_datacopy(SELF, ((vir_bytes)execi->hdr)+off,
 160         execi->proc_e, seg_addr, seg_bytes)) != OK) {
 161         printf("RS: exec read_seg: copy 0x%x bytes into %i at 0x%08lx failed: %i\n",
 162                 (int) seg_bytes, execi->proc_e, seg_addr, r);
 163   }
 164   return r;
 165 }