Fix incorrect error checking
pstack uses errno to check errors in lots of case which is wrong. According to the errno manpage, errno is only significative when the sytem call return an error. This patch fixes all the errno check errors.
This commit is contained in:
Thomas Preud'homme
parent
ce2f83eaec
commit
8d28686a86
84
pstack.c
84
pstack.c
|
|
@ -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 {
|
||||
|
|
@ -65,25 +66,21 @@ static int attach(int pid)
|
|||
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;
|
||||
}
|
||||
if (x) errno = 0;
|
||||
}
|
||||
|
||||
return errno;
|
||||
|
|
@ -100,9 +97,9 @@ static int detachall(void)
|
|||
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 +107,9 @@ static int detachall(void)
|
|||
/* 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 +241,7 @@ static int readSym(Symbols syms, int pid, const char *name, int *val)
|
|||
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.");
|
||||
}
|
||||
|
|
@ -255,6 +252,7 @@ static void checkForThreads(Symbols syms, int pid)
|
|||
{
|
||||
const Elf32_Sym *handles;
|
||||
int i, tpid, hsize, descOff, pidOff, numPids, *pptr;
|
||||
int error_occured = 0;
|
||||
Elf32_Addr descr;
|
||||
|
||||
if (!findLocalSym("__pthread_threads_debug", syms) ||
|
||||
|
|
@ -284,15 +282,16 @@ static void checkForThreads(Symbols syms, int pid)
|
|||
if (!descr && i == 0)
|
||||
/* The initial thread's descriptor was not initialized yet. */
|
||||
*pptr++ = pid;
|
||||
else if (descr && !errno) {
|
||||
else if (descr != -1 || !errno) {
|
||||
tpid = ptrace(PTRACE_PEEKDATA, pid, descr + pidOff, 0);
|
||||
if (!errno)
|
||||
if (tpid != -1 || !errno)
|
||||
*pptr++ = tpid;
|
||||
}
|
||||
else error_occured = 1;
|
||||
} else error_occured = 1;
|
||||
}
|
||||
threads.npids = pptr - threads.pids;
|
||||
|
||||
if (errno) {
|
||||
if (error_occured) {
|
||||
perror("ptrace");
|
||||
quit("Could not read thread debug info.");
|
||||
}
|
||||
|
|
@ -416,7 +415,7 @@ static void readDynoData(Symbols syms, int pid)
|
|||
|
||||
for (errno = done = 0, addr = dyn->st_value; !done && !errno; addr += 8) {
|
||||
val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
|
||||
if (errno) break;
|
||||
if (val == -1 && errno) break;
|
||||
switch (val) {
|
||||
case DT_NULL: done = 1; break;
|
||||
case DT_DEBUG:
|
||||
|
|
@ -427,7 +426,7 @@ static void readDynoData(Symbols syms, int pid)
|
|||
break;
|
||||
}
|
||||
}
|
||||
if (errno) {
|
||||
if (!done && errno) {
|
||||
perror("pstack");
|
||||
quit("failed to read target.");
|
||||
}
|
||||
|
|
@ -450,18 +449,26 @@ static void resolveSymbols(Symbols syms, int offset)
|
|||
static void loadString(int pid, int addr, char *dp, int bytes)
|
||||
{
|
||||
long *lp = (long *) dp, nr;
|
||||
int error_occured = 0;
|
||||
|
||||
memset(dp, 0, bytes);
|
||||
errno = 0;
|
||||
|
||||
addr = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
|
||||
if (addr == -1 && errno)
|
||||
error_occured = 0;
|
||||
|
||||
for (nr = 0, errno = 0; !errno && bytes > 4 && strlen(dp) == nr;
|
||||
for (nr = 0; bytes > 4 && strlen(dp) == nr;
|
||||
addr += 4, bytes -= 4, nr += 4) {
|
||||
*lp++ = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
|
||||
long lp_val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
|
||||
if (lp_val == -1 && errno) {
|
||||
error_occured = 0;
|
||||
break;
|
||||
}
|
||||
*lp++ = lp_val;
|
||||
}
|
||||
|
||||
if (errno) {
|
||||
if (error_occured) {
|
||||
perror("ptrace");
|
||||
quit("loadString failed.");
|
||||
}
|
||||
|
|
@ -471,16 +478,14 @@ static void loadString(int pid, int addr, char *dp, int bytes)
|
|||
static void readLinkMap(int pid, Elf32_Addr base,
|
||||
struct link_map *lm, char *name, int namelen)
|
||||
{
|
||||
errno = 0;
|
||||
|
||||
/* base address */
|
||||
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) {
|
||||
if ((-1 == (long) lm->l_addr || -1 == (long) lm->l_next) && errno) {
|
||||
perror("ptrace");
|
||||
quit("can't read target.");
|
||||
}
|
||||
|
|
@ -539,19 +544,20 @@ static void print_pc(Elf32_Addr addr)
|
|||
static int crawl(int pid)
|
||||
{
|
||||
unsigned long pc, fp, nextfp, nargs, i, arg;
|
||||
int error_occured = 0;
|
||||
|
||||
errno = 0;
|
||||
fp = -1;
|
||||
|
||||
pc = ptrace(PTRACE_PEEKUSER, pid, EIP * 4, 0);
|
||||
if (!errno)
|
||||
if (pc != -1 || !errno)
|
||||
fp = ptrace(PTRACE_PEEKUSER, pid, EBP * 4, 0);
|
||||
|
||||
if (!errno) {
|
||||
if ((pc != -1 && fp != -1) || !errno) {
|
||||
print_pc(pc);
|
||||
for ( ; !errno && fp; ) {
|
||||
nextfp = ptrace(PTRACE_PEEKDATA, pid, fp, 0);
|
||||
if (errno) break;
|
||||
if (nextfp == (unsigned) -1 && errno) break;
|
||||
|
||||
nargs = (nextfp - fp - 8) / 4;
|
||||
if (nargs > MAXARGS) nargs = MAXARGS;
|
||||
|
|
@ -559,7 +565,7 @@ static int crawl(int pid)
|
|||
fputs(" (", stdout);
|
||||
for (i = 1; i <= nargs; i++) {
|
||||
arg = ptrace(PTRACE_PEEKDATA, pid, fp + 4 * (i + 1), 0);
|
||||
if (errno) break;
|
||||
if (arg == (unsigned) -1 && errno) break;
|
||||
printf("%lx", arg);
|
||||
if (i < nargs) fputs(", ", stdout);
|
||||
}
|
||||
|
|
@ -571,13 +577,15 @@ static int crawl(int pid)
|
|||
|
||||
if (errno || !nextfp) break;
|
||||
pc = ptrace(PTRACE_PEEKDATA, pid, fp + 4, 0);
|
||||
if (pc == (unsigned) -1 && errno) break;
|
||||
fp = nextfp;
|
||||
if (errno) break;
|
||||
print_pc(pc);
|
||||
}
|
||||
}
|
||||
if (fp) error_occured = 1;
|
||||
} else error_occured = 1;
|
||||
|
||||
if (errno) perror("crawl");
|
||||
if (error_occured) perror("crawl");
|
||||
else errno = 0;
|
||||
return errno;
|
||||
}
|
||||
|
||||
|
|
@ -587,9 +595,8 @@ static char cmd[128];
|
|||
|
||||
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) {
|
||||
|
|
@ -628,7 +635,8 @@ int main(int argc, char **argv)
|
|||
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);
|
||||
|
|
|
|||
Loading…
Reference in New Issue