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lib: lpj: Refactor code.

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Only run one grep command to grep any number of files.
This commit is contained in:
Richard W.M. Jones
2012-11-26 09:00:16 +00:00
parent 8243c0c6f6
commit 567747f78e
1 changed files with 45 additions and 27 deletions
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72
src/lpj.c
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@@ -22,6 +22,7 @@
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
@@ -48,10 +49,9 @@
gl_lock_define_initialized (static, lpj_lock);
static int lpj = 0;
static int read_lpj_from_var_log_dmesg (guestfs_h *g);
static int read_lpj_from_var_log_boot_msg (guestfs_h *g);
static int read_lpj_from_dmesg (guestfs_h *g);
static int read_lpj_common (guestfs_h *g, const char *func, const char *command);
static int read_lpj_from_files (guestfs_h *g);
static int read_lpj_common (guestfs_h *g, const char *func, struct command *cmd);
int
guestfs___get_lpj (guestfs_h *g)
@@ -65,45 +65,66 @@ guestfs___get_lpj (guestfs_h *g)
/* Try reading lpj from these sources:
* - /proc/cpuinfo [in future]
* - dmesg
* - /var/log/dmesg
* - /var/log/boot.msg
* - files:
* + /var/log/dmesg
* + /var/log/boot.msg
*/
r = read_lpj_from_dmesg (g);
if (r > 0) {
lpj = r;
goto out;
}
r = read_lpj_from_var_log_dmesg (g);
if (r > 0) {
lpj = r;
goto out;
}
lpj = read_lpj_from_var_log_boot_msg (g);
lpj = read_lpj_from_files (g);
out:
gl_lock_unlock (lpj_lock);
return lpj;
}
/* Grep the output, and print just the matching string "lpj=NNN". */
#define GREP_FLAGS "-Eoh"
#define GREP_REGEX "lpj=[[:digit:]]+"
#define GREP_CMD "grep " GREP_FLAGS " '" GREP_REGEX "'"
static int
read_lpj_from_dmesg (guestfs_h *g)
{
return read_lpj_common (g, __func__,
"dmesg | grep -Eo 'lpj=[[:digit:]]+'");
struct command *cmd;
cmd = guestfs___new_command (g);
guestfs___cmd_add_string_unquoted (cmd, "dmesg | " GREP_CMD);
return read_lpj_common (g, __func__, cmd);
}
static int
read_lpj_from_var_log_dmesg (guestfs_h *g)
{
return read_lpj_common (g, __func__,
"grep -Eo 'lpj=[[:digit:]]+' /var/log/dmesg");
}
#define FILE1 "/var/log/dmesg"
#define FILE2 "/var/log/boot.msg"
static int
read_lpj_from_var_log_boot_msg (guestfs_h *g)
read_lpj_from_files (guestfs_h *g)
{
return read_lpj_common (g, __func__,
"grep -Eo 'lpj=[[:digit:]]+' /var/log/boot.msg");
struct command *cmd;
size_t files = 0;
cmd = guestfs___new_command (g);
guestfs___cmd_add_arg (cmd, "grep");
guestfs___cmd_add_arg (cmd, GREP_FLAGS);
guestfs___cmd_add_arg (cmd, GREP_REGEX);
if (access (FILE1, R_OK) == 0) {
guestfs___cmd_add_arg (cmd, FILE1);
files++;
}
if (access (FILE2, R_OK) == 0) {
guestfs___cmd_add_arg (cmd, FILE2);
files++;
}
if (files > 0)
return read_lpj_common (g, __func__, cmd);
guestfs___cmd_close (cmd);
debug (g, "%s: no boot messages files are readable", __func__);
return -1;
}
static void
@@ -116,21 +137,18 @@ read_all (guestfs_h *g, void *retv, const char *buf, size_t len)
}
static int
read_lpj_common (guestfs_h *g, const char *func, const char *command)
read_lpj_common (guestfs_h *g, const char *func, struct command *cmd)
{
struct command *cmd;
int r;
char *buf = NULL;
cmd = guestfs___new_command (g);
guestfs___cmd_add_string_unquoted (cmd, command);
guestfs___cmd_set_stdout_callback (cmd, read_all, &buf,
CMD_STDOUT_FLAG_WHOLE_BUFFER);
r = guestfs___cmd_run (cmd);
guestfs___cmd_close (cmd);
if (r == -1 || !WIFEXITED (r) || WEXITSTATUS (r) != 0) {
debug (g, "%s: command failed with code %d: %s", func, r, command);
debug (g, "%s: external command failed with code %d", func, r);
free (buf);
return -1;
}