ref: 6fa3e08412c49a188e2abe7d9ee54cd1f37a85f5
dir: /sys/src/cmd/snap/read.c/
#include <u.h> #include <libc.h> #include <bio.h> #include "snap.h" void panic(char *s) { fprint(2, "%s\n", s); abort(); exits(s); } static Proc* findpid(Proc *plist, long pid) { while(plist) { if(plist->pid == pid) break; plist = plist->link; } return plist; } Page* findpage(Proc *plist, long pid, int type, uvlong off) { Seg *s; int i; plist = findpid(plist, pid); if(plist == nil) panic("can't find referenced pid"); if(type == 't') { if(off%Pagesize) panic("bad text offset alignment"); s = plist->text; if(off >= s->len) return nil; return s->pg[off/Pagesize]; } s = nil; for(i=0; i<plist->nseg; i++) { s = plist->seg[i]; if(s && s->offset <= off && off < s->offset+s->len) break; s = nil; } if(s == nil) return nil; off -= s->offset; if(off%Pagesize) panic("bad mem offset alignment"); return s->pg[off/Pagesize]; } static int Breadnumber(Biobuf *b, char *buf) { int i; int c; int havedigits; havedigits = 0; for(i=0; i<22; i++){ if((c = Bgetc(b)) == Beof) return -1; if('0' <= c && c <= '9'){ *buf++ = c; havedigits = 1; }else if(c == ' '){ if(havedigits){ while((c = Bgetc(b)) == ' ') ; if(c != Beof) Bungetc(b); break; } }else{ werrstr("bad character %.2ux", c); return -1; } } *buf = 0; return 0; } static int Breadulong(Biobuf *b, ulong *x) { char buf[32]; if(Breadnumber(b, buf) < 0) return -1; *x = strtoul(buf, 0, 0); return 0; } static int Breaduvlong(Biobuf *b, uvlong *x) { char buf[32]; if(Breadnumber(b, buf) < 0) return -1; *x = strtoull(buf, 0, 0); return 0; } static Data* readdata(Biobuf *b) { Data *d; char str[32]; long len; if(Bread(b, str, 12) != 12) panic("can't read data hdr\n"); len = atoi(str); d = emalloc(sizeof(*d) + len); if(Bread(b, d->data, len) != len) panic("can't read data body\n"); d->len = len; return d; } static Seg* readseg(Seg **ps, Biobuf *b, Proc *plist) { Seg *s; Page **pp; int i, npg; int t; int n, len; ulong pid; uvlong off; char buf[Pagesize]; static char zero[Pagesize]; s = emalloc(sizeof *s); if(Breaduvlong(b, &s->offset) < 0 || Breaduvlong(b, &s->len) < 0) panic("error reading segment"); npg = (s->len + Pagesize-1)/Pagesize; s->npg = npg; if(s->npg == 0) return s; pp = emalloc(sizeof(*pp)*npg); s->pg = pp; *ps = s; len = Pagesize; for(i=0; i<npg; i++) { if(i == npg-1) len = s->len - i*Pagesize; switch(t = Bgetc(b)) { case 'z': pp[i] = datapage(zero, len); if(debug) fprint(2, "0x%.8llux all zeros\n", s->offset+i*Pagesize); break; case 'm': case 't': if(Breadulong(b, &pid) < 0 || Breaduvlong(b, &off) < 0) panic("error reading segment x"); pp[i] = findpage(plist, pid, t, off); if(pp[i] == nil) panic("bad page reference in snapshot"); if(debug) fprint(2, "0x%.8llux same as %s pid %lud 0x%.8llux\n", s->offset+i*Pagesize, t=='m'?"mem":"text", pid, off); break; case 'r': if((n=Bread(b, buf, len)) != len) sysfatal("short read of segment %d/%d at %llx: %r", n, len, Boffset(b)); pp[i] = datapage(buf, len); if(debug) fprint(2, "0x%.8llux is raw data\n", s->offset+i*Pagesize); break; default: fprint(2, "bad type char %#.2ux\n", t); panic("error reading segment"); } } return s; } Proc* readsnap(Biobuf *b) { char *q; char buf[12]; long pid; Proc *p, *plist; int i, n; if((q = Brdline(b, '\n')) == nil) panic("error reading snapshot file"); if(strncmp(q, "process snapshot", strlen("process snapshot")) != 0) panic("bad snapshot file format"); plist = nil; while(q = Brdline(b, '\n')) { q[Blinelen(b)-1] = 0; pid = atol(q); q += 12; p = findpid(plist, pid); if(p == nil) { p = emalloc(sizeof(*p)); p->link = plist; p->pid = pid; plist = p; } for(i=0; i<Npfile; i++) { if(strcmp(pfile[i], q) == 0) { p->d[i] = readdata(b); break; } } if(i != Npfile) continue; if(strcmp(q, "mem") == 0) { if(Bread(b, buf, 12) != 12) panic("can't read memory section"); n = atoi(buf); p->nseg = n; p->seg = emalloc(n*sizeof(*p->seg)); for(i=0; i<n; i++) readseg(&p->seg[i], b, plist); } else if(strcmp(q, "text") == 0) readseg(&p->text, b, plist); else panic("unknown section"); } return plist; }