selftests/x86: Clean up and document sscanf() usage
commit d8e92de8ef
upstream.
Replace a couple of magically connected buffer length literal constants with
a common definition that makes their relationship obvious. Also document
why our sscanf() usage is safe.
No intended functional changes.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Cc: shuah@kernel.org
Link: http://lkml.kernel.org/r/20180211205924.GA23210@light.dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
301e6fe091
commit
3eb95d5187
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@ -26,6 +26,9 @@
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# endif
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#endif
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/* max length of lines in /proc/self/maps - anything longer is skipped here */
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#define MAPS_LINE_LEN 128
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int nerrs = 0;
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typedef long (*getcpu_t)(unsigned *, unsigned *, void *);
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@ -37,17 +40,19 @@ static void *vsyscall_getcpu(void)
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{
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#ifdef __x86_64__
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FILE *maps;
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char line[128];
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char line[MAPS_LINE_LEN];
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bool found = false;
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maps = fopen("/proc/self/maps", "r");
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if (!maps) /* might still be present, but ignore it here, as we test vDSO not vsyscall */
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return NULL;
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while (fgets(line, sizeof(line), maps)) {
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while (fgets(line, MAPS_LINE_LEN, maps)) {
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char r, x;
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void *start, *end;
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char name[128];
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char name[MAPS_LINE_LEN];
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/* sscanf() is safe here as strlen(name) >= strlen(line) */
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if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
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&start, &end, &r, &x, name) != 5)
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continue;
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@ -33,6 +33,9 @@
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# endif
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#endif
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/* max length of lines in /proc/self/maps - anything longer is skipped here */
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#define MAPS_LINE_LEN 128
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static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
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int flags)
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{
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@ -98,7 +101,7 @@ static int init_vsys(void)
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#ifdef __x86_64__
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int nerrs = 0;
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FILE *maps;
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char line[128];
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char line[MAPS_LINE_LEN];
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bool found = false;
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maps = fopen("/proc/self/maps", "r");
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@ -108,10 +111,12 @@ static int init_vsys(void)
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return 0;
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}
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while (fgets(line, sizeof(line), maps)) {
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while (fgets(line, MAPS_LINE_LEN, maps)) {
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char r, x;
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void *start, *end;
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char name[128];
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char name[MAPS_LINE_LEN];
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/* sscanf() is safe here as strlen(name) >= strlen(line) */
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if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
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&start, &end, &r, &x, name) != 5)
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continue;
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