tlocaladdr.c - plan9port - [fork] Plan 9 from user space
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       tlocaladdr.c (1333B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 #include <bio.h>
            4 #include <mach.h>
            5 
            6 /*
            7  * XXX could remove the rock by hiding it in a special regs.
            8  * That would still be sleazy but would be thread-safe.
            9  */
           10 
           11 static struct {
           12         int found;
           13         int nframe;
           14         Loc l;
           15         char *fn;
           16         char *var;
           17         char *reg;
           18 } rock;
           19 
           20 static int
           21 ltrace(Map *map, Regs *regs, u64int pc, u64int nextpc, Symbol *sym, int depth)
           22 {
           23         u64int v;
           24         Symbol s1;
           25 
           26         USED(pc);
           27         USED(nextpc);
           28         USED(depth);
           29 
           30         if(sym==nil || strcmp(sym->name, rock.fn) != 0)
           31                 return ++rock.nframe < 40;
           32         if(rock.reg){
           33                 if(rget(regs, rock.reg, &v) < 0)
           34                         return 0;
           35                 rock.l = locconst(v);
           36                 rock.found = 1;
           37                 return 0;
           38         }
           39         if(lookuplsym(sym, rock.var, &s1) < 0)
           40                 return 0;
           41         if(locsimplify(map, regs, s1.loc, &rock.l) < 0)
           42                 return 0;
           43         if(rock.l.type == LREG && rget(regs, rock.l.reg, &v) >= 0)
           44                 rock.l = locconst(v);
           45         if(rock.l.type != LADDR && rock.l.type != LCONST)
           46                 return 0;
           47         rock.found = 1;
           48         return 0;
           49 }
           50 
           51 int
           52 localaddr(Map *map, Regs *regs, char *fn, char *var, u64int *val)
           53 {
           54         Regdesc *rp;
           55 
           56         rock.found = 0;
           57         rock.nframe = 0;
           58         rock.fn = fn;
           59         rock.reg = nil;
           60         rock.var = nil;
           61         for(rp=mach->reglist; rp->name; rp++)
           62                 if(strcmp(rp->name, var) == 0)
           63                         rock.reg = rp->name;
           64         if(!rock.reg)
           65                 rock.var = var;
           66         stacktrace(map, regs, ltrace);
           67         if(rock.found){
           68                 *val = rock.l.addr;
           69                 return 0;
           70         }
           71         return -1;
           72 }