minix/servers/rs/exec.c

   1 #include "inc.h"
   2 #include <assert.h>
   3 #include <sys/exec.h>
   4 #include <libexec.h>
   5 #include <minix/param.h>
   6 #include <machine/vmparam.h>
   7
   8 static int do_exec(int proc_e, char *exec, size_t exec_len, char *progname,
   9         char *frame, int frame_len, vir_bytes ps_str);
  10 static int exec_restart(int proc_e, int result, vir_bytes pc, vir_bytes ps_str);
  11 static int read_seg(struct exec_info *execi, off_t off,
  12         vir_bytes seg_addr, size_t seg_bytes);
  13
  14 /* Array of loaders for different object formats */
  15 static struct exec_loaders {
  16         libexec_exec_loadfunc_t load_object;
  17 } const exec_loaders[] = {
  18         { libexec_load_elf },
  19         { NULL }
  20 };
  21
  22 int srv_execve(int proc_e, char *exec, size_t exec_len, char **argv,
  23         char **envp)
  24 {
  25         size_t frame_size = 0;  /* Size of the new initial stack. */
  26         int argc = 0;           /* Argument count. */
  27         int envc = 0;           /* Environment count */
  28         char overflow = 0;      /* No overflow yet. */
  29         char *frame;
  30         struct ps_strings *psp;
  31         int vsp = 0;    /* (virtual) Stack pointer in new address space. */
  32
  33         char *progname;
  34         int r;
  35
  36         minix_stack_params(argv[0], argv, envp, &frame_size, &overflow,
  37                 &argc, &envc);
  38
  39         /* The party is off if there is an overflow. */
  40         if (overflow) {
  41                 errno = E2BIG;
  42                 return -1;
  43         }
  44
  45         /* Allocate space for the stack frame. */
  46         if ((frame = (char *) sbrk(frame_size)) == (char *) -1) {
  47                 errno = E2BIG;
  48                 return -1;
  49         }
  50
  51         minix_stack_fill(argv[0], argc, argv, envc, envp, frame_size, frame,
  52                 &vsp, &psp);
  53
  54         (progname=strrchr(argv[0], '/')) ? progname++ : (progname=argv[0]);
  55
  56         r = do_exec(proc_e, exec, exec_len, progname, frame, frame_size,
  57                 vsp + ((char *)psp - frame));
  58
  59         /* Failure, return the memory used for the frame and exit. */
  60         (void) sbrk(-frame_size);
  61
  62         return r;
  63 }
  64
  65
  66 static int do_exec(int proc_e, char *exec, size_t exec_len, char *progname,
  67         char *frame, int frame_len, vir_bytes ps_str)
  68 {
  69         int r;
  70         vir_bytes vsp;
  71         struct exec_info execi;
  72         int i;
  73
  74         memset(&execi, 0, sizeof(execi));
  75
  76         execi.stack_high = kinfo.user_sp;
  77         execi.stack_size = DEFAULT_STACK_LIMIT;
  78         execi.proc_e = proc_e;
  79         execi.hdr = exec;
  80         execi.filesize = execi.hdr_len = exec_len;
  81         strncpy(execi.progname, progname, PROC_NAME_LEN-1);
  82         execi.progname[PROC_NAME_LEN-1] = '\0';
  83         execi.frame_len = frame_len;
  84
  85         /* callback functions and data */
  86         execi.copymem = read_seg;
  87         execi.clearproc = libexec_clearproc_vm_procctl;
  88         execi.clearmem = libexec_clear_sys_memset;
  89         execi.allocmem_prealloc_cleared = libexec_alloc_mmap_prealloc_cleared;
  90         execi.allocmem_prealloc_junk = libexec_alloc_mmap_prealloc_junk;
  91         execi.allocmem_ondemand = libexec_alloc_mmap_ondemand;
  92
  93         for(i = 0; exec_loaders[i].load_object != NULL; i++) {
  94             r = (*exec_loaders[i].load_object)(&execi);
  95             /* Loaded successfully, so no need to try other loaders */
  96             if (r == OK) break;
  97         }
  98
  99         /* No exec loader could load the object */
 100         if (r != OK) {
 101             printf("RS: do_exec: loading error %d\n", r);
 102             return r;
 103         }
 104
 105         /* Inform PM */
 106         if((r = libexec_pm_newexec(execi.proc_e, &execi)) != OK)
 107                 return r;
 108
 109         /* Patch up stack and copy it from RS to new core image. */
 110         vsp = execi.stack_high - frame_len;
 111         r = sys_datacopy(SELF, (vir_bytes) frame,
 112                 proc_e, (vir_bytes) vsp, (phys_bytes)frame_len);
 113         if (r != OK) {
 114                 printf("do_exec: copying out new stack failed: %d\n", r);
 115                 exec_restart(proc_e, r, execi.pc, ps_str);
 116                 return r;
 117         }
 118
 119         return exec_restart(proc_e, OK, execi.pc, ps_str);
 120 }
 121
 122 /*===========================================================================*
 123  *                              exec_restart                                 *
 124  *===========================================================================*/
 125 static int exec_restart(int proc_e, int result, vir_bytes pc, vir_bytes ps_str)
 126 {
 127         int r;
 128         message m;
 129
 130         memset(&m, 0, sizeof(m));
 131         m.m_type = PM_EXEC_RESTART;
 132         m.m_rs_pm_exec_restart.endpt = proc_e;
 133         m.m_rs_pm_exec_restart.result = result;
 134         m.m_rs_pm_exec_restart.pc = pc;
 135         m.m_rs_pm_exec_restart.ps_str = ps_str;
 136
 137         r = ipc_sendrec(PM_PROC_NR, &m);
 138         if (r != OK)
 139                 return r;
 140
 141         return m.m_type;
 142 }
 143
 144 /*===========================================================================*
 145  *                             read_seg                                     *
 146  *===========================================================================*/
 147 static int read_seg(
 148 struct exec_info *execi,       /* various data needed for exec */
 149 off_t off,                     /* offset in file */
 150 vir_bytes seg_addr,            /* address to load segment */
 151 size_t seg_bytes           /* how much is to be transferred? */
 152 )
 153 {
 154 /*
 155  * The byte count on read is usually smaller than the segment count, because
 156  * a segment is padded out to a click multiple, and the data segment is only
 157  * partially initialized.
 158  */
 159
 160   int r;
 161
 162   if (off+seg_bytes > execi->hdr_len) return ENOEXEC;
 163   if((r= sys_datacopy(SELF, ((vir_bytes)execi->hdr)+off,
 164         execi->proc_e, seg_addr, seg_bytes)) != OK) {
 165         printf("RS: exec read_seg: copy 0x%x bytes into %i at 0x%08lx failed: %i\n",
 166                 seg_bytes, execi->proc_e, seg_addr, r);
 167   }
 168   return r;
 169 }