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Fix lame kernel version checking code

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The code "os_release[0] >= '3'" is not good for any
finer-grained checks such as "kernel >= 3.2.1".
Let's proactively fix it.

* strace.c: Change os_release from string to integer.
(get_os_release): Parse uname.release to KERNEL_VERSION
representation.
(init): Convert kernel version check to KERNEL_VERSION.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2012-03-15 14:36:28 +01:00
parent 61e7aad9fa
commit 6e0bfd11ac
1 changed files with 23 additions and 7 deletions
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30
strace.c
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@ -144,7 +144,7 @@ static struct tcb **tcbtab;
static unsigned int nprocs, tcbtabsize;
static const char *progname;
static char *os_release; /* from uname() */
static unsigned os_release; /* generated from uname()'s u.release */
static int detach(struct tcb *tcp);
static int trace(void);
@ -1169,15 +1169,31 @@ test_ptrace_seize(void)
# define test_ptrace_seize() ((void)0)
# endif
static void
static unsigned
get_os_release(void)
{
unsigned rel;
const char *p;
struct utsname u;
if (uname(&u) < 0)
perror_msg_and_die("uname");
os_release = strdup(u.release);
if (!os_release)
die_out_of_memory();
/* u.release has this form: "3.2.9[-some-garbage]" */
rel = 0;
p = u.release;
for (;;) {
if (!(*p >= '0' && *p <= '9'))
error_msg_and_die("Bad OS release string: '%s'", u.release);
/* Note: this open-codes KERNEL_VERSION(): */
rel = (rel << 8) | atoi(p);
if (rel >= KERNEL_VERSION(1,0,0))
break;
while (*p >= '0' && *p <= '9')
p++;
if (*p != '.')
error_msg_and_die("Bad OS release string: '%s'", u.release);
p++;
}
return rel;
}
/*
@ -1200,7 +1216,7 @@ init(int argc, char *argv[])
strace_tracer_pid = getpid();
get_os_release();
os_release = get_os_release();
/* Allocate the initial tcbtab. */
tcbtabsize = argc; /* Surely enough for all -p args. */
@ -1896,7 +1912,7 @@ trace(void)
* PTRACE_GETEVENTMSG returns old pid starting from Linux 3.0.
* On 2.6 and earlier, it can return garbage.
*/
if (event == PTRACE_EVENT_EXEC && os_release[0] >= '3') {
if (event == PTRACE_EVENT_EXEC && os_release >= KERNEL_VERSION(3,0,0)) {
long old_pid = 0;
if (ptrace(PTRACE_GETEVENTMSG, pid, NULL, (long) &old_pid) >= 0
&& old_pid > 0