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- /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
- */
- #include <u.h>
- #include <libc.h>
- #include <bio.h>
- #include <thread.h>
- enum {
- Stacksize = 8*1024,
- Bufsize = 8*1024,
- };
- Channel *out;
- Channel *quit;
- Channel *forkc;
- int nread = 0;
- typedef struct Str Str;
- struct Str {
- char *buf;
- int len;
- };
- static void
- die(char *s)
- {
- fprint(2, "%s\n", s);
- exits(s);
- }
- static void
- cwrite(int fd, char *path, char *cmd, int len)
- {
- if (write(fd, cmd, len) < len) {
- fprint(2, "cwrite: %s: failed %d bytes: %r\n", path, len);
- sendp(quit, nil);
- threadexits(nil);
- }
- }
- void
- reader(void *v)
- {
- uintptr_t cfd, tfd, forking = 0, pid, newpid;
- char *ctl, *truss;
- Str *s;
- pid = (int)(uintptr_t)v;
- ctl = smprint("/proc/%d/ctl", pid);
- if ((cfd = open(ctl, OWRITE)) < 0)
- die(smprint("%s: %r", ctl));
- truss = smprint("/proc/%d/syscall", pid);
- if ((tfd = open(truss, OREAD)) < 0)
- die(smprint("%s: %r", truss));
- cwrite(cfd, ctl, "stop", 4);
- cwrite(cfd, truss, "startsyscall", 12);
- s = mallocz(sizeof(Str) + Bufsize, 1);
- s->buf = (char *)&s[1];
- while((s->len = pread(tfd, s->buf, Bufsize - 1, 0)) > 0){
- if (forking && s->buf[1] == '=' && s->buf[3] != '-') {
- forking = 0;
- newpid = strtol(&s->buf[3], 0, 0);
- sendp(forkc, (void*)newpid);
- procrfork(reader, (void*)newpid, Stacksize, 0);
- }
- /*
- * There are three tests here and they (I hope) guarantee
- * no false positives.
- */
- if (strstr(s->buf, " Rfork") != nil) {
- char *a[8];
- char *rf;
- rf = strdup(s->buf);
- if (tokenize(rf, a, 8) == 5) {
- uint32_t flags;
- flags = strtoul(a[4], 0, 16);
- if (flags & RFPROC)
- forking = 1;
- }
- free(rf);
- }
- sendp(out, s);
- cwrite(cfd, truss, "startsyscall", 12);
- s = mallocz(sizeof(Str) + Bufsize, 1);
- s->buf = (char *)&s[1];
- }
- sendp(quit, nil);
- threadexitsall(nil);
- }
- void
- writer(void *v)
- {
- int newpid;
- Alt a[4];
- Str *s;
- a[0].op = CHANRCV;
- a[0].c = quit;
- a[0].v = nil;
- a[1].op = CHANRCV;
- a[1].c = out;
- a[1].v = &s;
- a[2].op = CHANRCV;
- a[2].c = forkc;
- a[2].v = &newpid;
- a[3].op = CHANEND;
- for(;;)
- switch(alt(a)){
- case 0:
- nread--;
- if(nread <= 0)
- goto done;
- break;
- case 1:
- /* it's a nice null terminated thing */
- fprint(2, "%s", s->buf);
- free(s);
- break;
- case 2:
- // procrfork(reader, (void*)newpid, Stacksize, 0);
- nread++;
- break;
- }
- done:
- exits(nil);
- }
- void
- usage(void)
- {
- fprint(2, "Usage: ratrace [-c cmd [arg...]] | [pid]\n");
- exits("usage");
- }
- void
- threadmain(int argc, char **argv)
- {
- uintptr_t pid;
- char *cmd = nil;
- char **args = nil;
- /*
- * don't bother with fancy arg processing, because it picks up options
- * for the command you are starting. Just check for -c as argv[1]
- * and then take it from there.
- */
- if (argc < 2)
- usage();
- if (argv[1][0] == '-')
- switch(argv[1][1]) {
- case 'c':
- if (argc < 3)
- usage();
- cmd = strdup(argv[2]);
- args = &argv[2];
- break;
- default:
- usage();
- }
- /* run a command? */
- if(cmd) {
- pid = fork();
- if (pid < 0)
- sysfatal("fork failed: %r");
- if(pid == 0) {
- exec(cmd, args);
- if(cmd[0] != '/')
- exec(smprint("/bin/%s", cmd), args);
- sysfatal("exec %s failed: %r", cmd);
- }
- } else {
- if(argc != 2)
- usage();
- pid = atoi(argv[1]);
- }
- out = chancreate(sizeof(char*), 0);
- quit = chancreate(sizeof(char*), 0);
- forkc = chancreate(sizeof(uint32_t *), 0);
- nread++;
- procrfork(writer, nil, Stacksize, 0);
- reader((void*)pid);
- }
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