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authorMike Frysinger <vapier@gentoo.org>2005-04-16 03:59:42 +0000
committerMike Frysinger <vapier@gentoo.org>2005-04-16 03:59:42 +0000
commit650870cb833b700fc13a484cbbd9f61ad049b4f3 (patch)
treeff5e06a5fa43a961e352d5674c7fe154b21ed48b /libc
parentd1abf5ce4c95c2a38f9ac92ae6805a0344de9c7d (diff)
In Bug 116, dicksnippe writes:
uClibc's mkstemp/mktemp tries to read /dev/urandom (or /dev/random) to generate random contents for the .XXXXXX part of its argument. In a chrooted environment /dev/[u]random might not be available. Thus the mkstemp call fails. Add back in the braindamaged gettimeofday/getpid code, but only as a fallback for when reading /dev/[u]random fail for whatever reasons.
Diffstat (limited to 'libc')
-rw-r--r--libc/misc/internals/tempname.c35
1 files changed, 32 insertions, 3 deletions
diff --git a/libc/misc/internals/tempname.c b/libc/misc/internals/tempname.c
index c1b211241..cd1f3497b 100644
--- a/libc/misc/internals/tempname.c
+++ b/libc/misc/internals/tempname.c
@@ -26,6 +26,11 @@
* Don't use brain damaged getpid() based randomness.
*/
+/* April 15, 2005 Mike Frysinger
+ *
+ * Use brain damaged getpid() if real random fails.
+ */
+
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
@@ -132,6 +137,30 @@ static unsigned int fillrand(unsigned char *buf, unsigned int len)
return result;
}
+static void brain_damaged_fillrand(unsigned char *buf, unsigned int len)
+{
+ int i, k;
+ struct timeval tv;
+ uint32_t high, low, rh;
+ static uint64_t value;
+ gettimeofday(&tv, NULL);
+ value += ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid();
+ low = value & UINT32_MAX;
+ high = value >> 32;
+ for (i = 0; i < len; ++i) {
+ rh = high % 62;
+ high /= 62;
+#define L ((UINT32_MAX % 62 + 1) % 62)
+ k = (low % 62) + (L * rh);
+#undef L
+#define H ((UINT32_MAX / 62) + ((UINT32_MAX % 62 + 1) / 62))
+ low = (low / 62) + (H * rh) + (k / 62);
+#undef H
+ k %= 62;
+ buf[i] = letters[k];
+ }
+}
+
/* Generate a temporary file name based on TMPL. TMPL must match the
rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed
does not exist at the time of the call to __gen_tempname. TMPL is
@@ -164,8 +193,9 @@ int __gen_tempname (char *tmpl, int kind)
XXXXXX = &tmpl[len - 6];
/* Get some random data. */
- if (fillrand(randomness, sizeof(randomness)) != sizeof(randomness)) {
- goto all_done;
+ if (fillrand(randomness, sizeof(randomness)) != sizeof(randomness)) {
+ /* if random device nodes failed us, lets use the braindamaged ver */
+ brain_damaged_fillrand(randomness, sizeof(randomness));
}
for (i = 0 ; i < sizeof(randomness) ; i++) {
k = ((randomness[i]) % 62);
@@ -219,7 +249,6 @@ int __gen_tempname (char *tmpl, int kind)
}
/* We got out of the loop because we ran out of combinations to try. */
-all_done:
__set_errno (EEXIST);
return -1;
}