[lvm-devel] [PATCH 2/2] Make _init_rand() thread safe - use rand_r() instead of rand().
Dave Wysochanski
dwysocha at redhat.com
Sat Dec 6 16:12:46 UTC 2008
Use good entropy for seed value if possible.
Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
---
lib/commands/toolcontext.c | 10 ++++++++++
lib/commands/toolcontext.h | 1 +
lib/format_text/archive.c | 3 ++-
lib/format_text/format-text.c | 3 ++-
lib/misc/lvm-file.c | 5 +++--
lib/misc/lvm-file.h | 3 ++-
tools/lvmcmdline.c | 7 -------
7 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/lib/commands/toolcontext.c b/lib/commands/toolcontext.c
index f49c7c6..a987469 100644
--- a/lib/commands/toolcontext.c
+++ b/lib/commands/toolcontext.c
@@ -979,6 +979,14 @@ static int _init_backup(struct cmd_context *cmd)
return 1;
}
+static void _init_rand(struct cmd_context *cmd)
+{
+ if (read_urandom(&cmd->rand_seed, sizeof(cmd->rand_seed)))
+ return;
+
+ cmd->rand_seed = (unsigned) time(NULL) + (unsigned) getpid();
+}
+
/* Entry point */
struct cmd_context *create_toolcontext(struct arg *the_args, unsigned is_static,
unsigned is_long_lived)
@@ -1077,6 +1085,8 @@ struct cmd_context *create_toolcontext(struct arg *the_args, unsigned is_static,
if (!_init_backup(cmd))
goto error;
+ _init_rand(cmd);
+
cmd->default_settings.cache_vgmetadata = 1;
cmd->current_settings = cmd->default_settings;
diff --git a/lib/commands/toolcontext.h b/lib/commands/toolcontext.h
index 6cbf6a6..4ea3486 100644
--- a/lib/commands/toolcontext.h
+++ b/lib/commands/toolcontext.h
@@ -62,6 +62,7 @@ struct cmd_context {
const char *hostname;
const char *kernel_vsn;
+ unsigned rand_seed;
char *cmd_line;
struct command *command;
struct arg *args;
diff --git a/lib/format_text/archive.c b/lib/format_text/archive.c
index b232db7..3e5b0c4 100644
--- a/lib/format_text/archive.c
+++ b/lib/format_text/archive.c
@@ -236,7 +236,8 @@ int archive_vg(struct volume_group *vg,
/*
* Write the vg out to a temporary file.
*/
- if (!create_temp_name(dir, temp_file, sizeof(temp_file), &fd)) {
+ if (!create_temp_name(dir, temp_file, sizeof(temp_file), &fd,
+ &vg->cmd->rand_seed)) {
log_err("Couldn't create temporary archive name.");
return 0;
}
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index fc4e5ff..af9c2ac 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -848,7 +848,8 @@ static int _vg_write_file(struct format_instance *fid __attribute((unused)),
return 0;
}
- if (!create_temp_name(temp_dir, temp_file, sizeof(temp_file), &fd)) {
+ if (!create_temp_name(temp_dir, temp_file, sizeof(temp_file), &fd,
+ &vg->cmd->rand_seed)) {
log_err("Couldn't create temporary text file name.");
return 0;
}
diff --git a/lib/misc/lvm-file.c b/lib/misc/lvm-file.c
index 3e812d1..a5a5f2b 100644
--- a/lib/misc/lvm-file.c
+++ b/lib/misc/lvm-file.c
@@ -29,7 +29,8 @@
* rename the file after successfully writing it. Grab
* NFS-supported exclusive fcntl discretionary lock.
*/
-int create_temp_name(const char *dir, char *buffer, size_t len, int *fd)
+int create_temp_name(const char *dir, char *buffer, size_t len, int *fd,
+ unsigned *seed)
{
int i, num;
pid_t pid;
@@ -41,7 +42,7 @@ int create_temp_name(const char *dir, char *buffer, size_t len, int *fd)
.l_len = 0
};
- num = rand();
+ num = rand_r(seed);
pid = getpid();
if (gethostname(hostname, sizeof(hostname)) < 0) {
log_sys_error("gethostname", "");
diff --git a/lib/misc/lvm-file.h b/lib/misc/lvm-file.h
index 8110be1..07327c3 100644
--- a/lib/misc/lvm-file.h
+++ b/lib/misc/lvm-file.h
@@ -19,7 +19,8 @@
/*
* Create a temporary filename, and opens a descriptor to the file.
*/
-int create_temp_name(const char *dir, char *buffer, size_t len, int *fd);
+int create_temp_name(const char *dir, char *buffer, size_t len, int *fd,
+ unsigned *seed);
/*
* NFS-safe rename of a temporary file to a common name, designed
diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c
index 78e9e60..29b4c15 100644
--- a/tools/lvmcmdline.c
+++ b/tools/lvmcmdline.c
@@ -997,11 +997,6 @@ int lvm_split(char *str, int *argc, char **argv, int max)
return *argc;
}
-static void _init_rand(void)
-{
- srand((unsigned) time(NULL) + (unsigned) getpid());
-}
-
static const char *_get_cmdline(pid_t pid)
{
static char _proc_cmdline[32];
@@ -1096,8 +1091,6 @@ struct cmd_context *init_lvm(unsigned is_static)
if (!(cmd = create_toolcontext(_cmdline.the_args, is_static, 0)))
return_NULL;
- _init_rand();
-
_apply_settings(cmd);
return cmd;
--
1.5.5.1
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