setrlimit/getrlimit: fix prlimit64 syscall use for 32-bit CPUs

Commit 95e38b37 ("add support for systems without legacy setrlimit/getrlimit
syscalls") has added use of the prlimit64 syscall in getrlimit and setrlimit
functions. This change causes memory corruption on getrlimit call for 32-bit
CPUs like ARC, as ARC doesn't have ugetrlimit syscall and uses prlimit64.
Also, setrlimit has been broken by prlimit64 call on 32-bit CPUs like, i386,
ARM, ARC.

For the prlimit64 syscall the kernel expects an rlimit struct with 64-bit fields,
but on 32-bit CPUs without _FILE_OFFSET_BITS=64 the struct rlimit has 32-bit
fields.

Add safe implementations of getrlimit, setrlimit, prlimit for 32-bit CPUs with a
local struct rlimit64 variable for use in the prlimit64 syscall.
For 64-bit CPUs and configurations with _FILE_OFFSET_BITS=64 use
getrlimit, setrlimit, prlimit as aliases to getrlimit64, setrlimit64 and
prlimit64. Add a new function prlimit64.

Tested on aarch64, arm, i386, arc.

Fixes: 95e38b37 ("add support for systems without legacy setrlimit/getrlimit syscalls")
Signed-off-by: Pavel Kozlov <pavel.kozlov@synopsys.com>

1 files changed, 27 insertions, 14 deletions

diff --git a/libc/sysdeps/linux/common/setrlimit.c b/libc/sysdeps/linux/common/setrlimit.c
index 8381afc61..9c6707235 100644
--- a/libc/sysdeps/linux/common/setrlimit.c
+++ b/libc/sysdeps/linux/common/setrlimit.c
@@ -23,21 +23,41 @@ int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits)
 {
 	return __syscall_usetrlimit(resource, rlimits);
 }
+libc_hidden_def(setrlimit)
 
-#else
+#elif defined(__NR_prlimit64)
 
-# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__)
+/* Use prlimit64 if present, the prlimit64 syscall is free from a back
+   compatibility stuff for setrlimit */
 
-#  if defined(__NR_prlimit64)
+ # if __WORDSIZE == 32 && !defined(__USE_FILE_OFFSET64)
+/* If struct rlimit has 64-bit fields (if __WORDSIZE == 64 or __USE_FILE_OFFSET64
+   is defined), then use setrlimit as an alias to setrlimit64, see setrlimit64.c */
 int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits)
 {
-	return INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL);
+	struct rlimit64 rlimits64;
+
+	if (rlimits->rlim_cur == RLIM_INFINITY)
+		rlimits64.rlim_cur = RLIM64_INFINITY;
+	else
+		rlimits64.rlim_cur = rlimits->rlim_cur;
+	if (rlimits->rlim_max == RLIM_INFINITY)
+		rlimits64.rlim_max = RLIM64_INFINITY;
+	else
+		rlimits64.rlim_max = rlimits->rlim_max;
+
+	return INLINE_SYSCALL (prlimit64, 4, 0, resource, &rlimits64, NULL);
 }
-#  else
+libc_hidden_def(setrlimit)
+# endif
+
+#else
+
+# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__)
+
 /* We don't need to wrap setrlimit() */
 _syscall2(int, setrlimit, __rlimit_resource_t, resource,
 		const struct rlimit *, rlim)
-#  endif
 
 # else
 
@@ -66,16 +86,9 @@ int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits)
 								  RLIM_INFINITY >> 1);
 	rlimits_small.rlim_max = MIN((unsigned long int) rlimits->rlim_max,
 								  RLIM_INFINITY >> 1);
-#  if defined(__NR_prlimit64)
-	return INLINE_SYSCALL (prlimit64, 4, 0, resource, &rlimits_small, NULL);
-#  else
 	return __syscall_setrlimit(resource, &rlimits_small);
-#  endif
 }
 # endif
-#endif
-libc_hidden_def(setrlimit)
 
-#if __WORDSIZE == 64
-strong_alias_untyped(setrlimit, setrlimit64)
+libc_hidden_def(setrlimit)
 #endif