tag 355660 patch
thanks
A partial patch is attached; I also fix an uninitialized integer that
would result in the display of a uninitialized string in the
(hypothetical?) case that a process is attached, but its commandline
can't be read.
--- pstack.c 2006-03-06 19:20:28.000000000 -0500
+++ /tmp/pstack.c 2006-03-07 00:10:32.000000000 -0500
@@ -49,6 +49,7 @@
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
+#include <limits.h>
static int thePid; /* pid requested by caller. */
static struct {
@@ -64,25 +65,20 @@
{
int status;
- errno = 0;
- ptrace(PTRACE_ATTACH, pid, 0, 0);
-
- if (errno)
+ if (-1==ptrace(PTRACE_ATTACH, pid, 0, 0))
return errno;
- waitpid (pid, &status, WUNTRACED);
-
/* If we failed due to an ECHILD, then retry with the __WCLONE
flag. Note we loop as the the PID we get back may not be
one we care about. */
- if (errno == ECHILD) {
+ if (-1==waitpid(pid, &status, WUNTRACED) && errno == ECHILD) {
int x;
errno = 0;
while (1) {
x = waitpid (-1, &status, (__WCLONE));
- if (x == pid || x < 0 || errno != 0) break;
+ if (x == pid || x < 0) break;
}
}
@@ -100,9 +96,9 @@
if (threads.found) {
for (i = 0; i < threads.npids; i++) {
if (threads.pids[i] != thePid && threads.attached[i]) {
- errno = 0;
- ptrace(PTRACE_DETACH, threads.pids[i], 0, 0);
- if (errno) perror("detach");
+ if (-1==ptrace(PTRACE_DETACH, threads.pids[i], 0, 0)) {
+ perror("detach");
+ }
}
}
}
@@ -110,9 +106,9 @@
/* Now attach from the thread we initially attached to. Note that
the PTRACE_DETACH will continue the thread, so there is no need
is issue a separate PTRACE_CONTINUE call. */
- ptrace(PTRACE_DETACH, thePid, 0, 0);
-
- return errno;
+ if (-1==ptrace(PTRACE_DETACH, thePid, 0, 0))
+ return errno;
+ return 0;
}
static void handle_signal (int signum)
@@ -244,7 +240,7 @@
if (!(sym = findLocalSym(name, syms))) return 0;
errno = 0;
*val = ptrace(PTRACE_PEEKDATA, pid, sym->st_value, 0);
- if (errno) {
+ if (-1==*val && errno) {
perror("ptrace");
quit("Could not read thread debug info.");
}
@@ -286,7 +282,7 @@
*pptr++ = pid;
else if (descr && !errno) {
tpid = ptrace(PTRACE_PEEKDATA, pid, descr + pidOff, 0);
- if (!errno)
+ if (-1!=tpid || !errno)
*pptr++ = tpid;
}
}
@@ -414,7 +410,7 @@
for (errno = done = 0, addr = dyn->st_value; !done && !errno; addr += 8) {
val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
- if (errno) break;
+ if (-1==val && errno) break;
switch (val) {
case DT_NULL: done = 1; break;
case DT_DEBUG:
@@ -475,7 +471,7 @@
lm->l_addr = (Elf32_Addr) ptrace(PTRACE_PEEKDATA, pid,
base + OFFSET(l_addr, *lm), 0);
/* next element of link map chain */
- if (!errno)
+ if (-1!=(long)lm->l_addr || !errno)
lm->l_next = (struct link_map *) ptrace(PTRACE_PEEKDATA, pid,
base + OFFSET(l_next, *lm), 0);
if (errno) {
@@ -549,7 +545,7 @@
print_pc(pc);
for ( ; !errno && fp; ) {
nextfp = ptrace(PTRACE_PEEKDATA, pid, fp, 0);
- if (errno) break;
+ if ((unsigned)-1==nextfp && errno) break;
nargs = (nextfp - fp - 8) / 4;
if (nargs > MAXARGS) nargs = MAXARGS;
@@ -557,7 +553,7 @@
fputs(" (", stdout);
for (i = 1; i <= nargs; i++) {
arg = ptrace(PTRACE_PEEKDATA, pid, fp + 4 * (i + 1), 0);
- if (errno) break;
+ if ((unsigned)-1==arg && errno) break;
printf("%lx", arg);
if (i < nargs) fputs(", ", stdout);
}
@@ -570,7 +566,7 @@
if (errno || !nextfp) break;
pc = ptrace(PTRACE_PEEKDATA, pid, fp + 4, 0);
fp = nextfp;
- if (errno) break;
+ if ((unsigned)-1==pc && errno) break;
print_pc(pc);
}
}
@@ -585,9 +581,8 @@
static char *cmdLine(int pid)
{
- int fd, len, i;
+ int fd, len=-1, i;
- fd = -1;
sprintf(cmd, "/proc/%d/cmdline", pid);
if ((fd = open(cmd, O_RDONLY)) >= 0 &&
(len = read(fd, cmd, sizeof(cmd))) > 0) {
@@ -626,7 +621,8 @@
for (argc--, argv++; argc > 0; argc--, argv++) {
char *endptr = NULL;
thePid = strtol(*argv, &endptr, 0);
- if (!*argv || *endptr || errno==ERANGE)
+ if (!*argv || *endptr || (errno==ERANGE &&
+ (thePid==LONG_MIN || thePid==LONG_MAX)))
usage(argv0, *argv);
if (!thePid || thePid == getpid()) {
fprintf(stderr, "Invalid PID %d\n", thePid);
