Fix user space logrotation bug.

Replace file stream functions in user space logging with their file descriptor
counter parts, which are safe to be called from a signal handler.
(cherry picked from commit 342ac1dc1a5ebc9aef55808b2d42436be3efb88d)

diff --git a/xseg/sys/user/_sysutil.h b/xseg/sys/user/_sysutil.h
index 1dffbdc..164eead 100644 (file)
--- a/xseg/sys/user/_sysutil.h
+++ b/xseg/sys/user/_sysutil.h
@@ -48,8 +48,10 @@
 
 
 struct log_ctx {
+       int stdout_orig;
+       int stderr_orig;
        char filename[MAX_LOGFILE_LEN];
-       FILE *logfile;
+       volatile int logfile;
        char peer_name[MAX_PEER_NAME];
        unsigned int log_level;
        uint32_t flags;

diff --git a/xseg/sys/user/xseg_user.c b/xseg/sys/user/xseg_user.c
index cfc45b5..f84bc66 100644 (file)
--- a/xseg/sys/user/xseg_user.c
+++ b/xseg/sys/user/xseg_user.c
@@ -43,6 +43,9 @@
 #include <sys/syscall.h>
 #include <errno.h>
 #include <sys/util.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <sys/time.h>
 #include <execinfo.h>
 #include <sys/domain.h>
@@ -124,7 +127,7 @@ void __get_current_time(struct timeval *tv) {
 int __renew_logctx(struct log_ctx *lc, char *peer_name,
                enum log_level log_level, char *logfile, uint32_t flags)
 {
-       FILE *file;
+       int fd, tmp_fd;
 
        if (peer_name){
                strncpy(lc->peer_name, peer_name, MAX_PEER_NAME);
@@ -136,24 +139,29 @@ int __renew_logctx(struct log_ctx *lc, char *peer_name,
                strncpy(lc->filename, logfile, MAX_LOGFILE_LEN);
                lc->filename[MAX_LOGFILE_LEN - 1] = 0;
        }
-       else if (!(flags & REOPEN_FILE) || lc->logfile == stderr)
+       else if (!(flags & REOPEN_FILE) || lc->logfile == STDERR_FILENO)
                return 0;
 
-       if (lc->logfile == stderr)
-               file = fopen(lc->filename, "a");
-       else
-               file = freopen(lc->filename, "a", lc->logfile);
-       if (!file) {
+       fd = open(lc->filename, O_WRONLY|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR);
+       if (fd < 1){
                return -1;
        }
 
+       tmp_fd = lc->logfile;
+       lc->logfile = fd;
+       close(tmp_fd);
+
        flags &= ~REOPEN_FILE;
-       if ((flags|lc->flags) & REDIRECT_STDOUT)
-               if (!freopen(lc->filename, "a", stdout))
+       if ((flags|lc->flags) & REDIRECT_STDOUT){
+               fd = dup2(lc->logfile, STDOUT_FILENO);
+               if (fd < 0)
                        return -1;
-       if ((flags|lc->flags) & REDIRECT_STDERR)
-               if (!freopen(lc->filename, "a", stderr))
+       }
+       if ((flags|lc->flags) & REDIRECT_STDERR){
+               fd = dup2(lc->logfile, STDERR_FILENO);
+               if (fd < 0)
                        return -1;
+       }
        lc->flags |= flags;
 
        return 0;
@@ -164,7 +172,7 @@ int (*renew_logctx)(struct log_ctx *lc, char *peer_name,
 int __init_logctx(struct log_ctx *lc, char *peer_name,
                enum log_level log_level, char *logfile, uint32_t flags)
 {
-       FILE *file;
+       int fd;
 
        if (peer_name){
                strncpy(lc->peer_name, peer_name, MAX_PEER_NAME);
@@ -174,27 +182,47 @@ int __init_logctx(struct log_ctx *lc, char *peer_name,
                return -1;
        }
 
+       /* set logfile to stderr by default */
+       lc->logfile = STDERR_FILENO;
+
+       /* duplicate stdout, stderr */
+       fd = dup(STDOUT_FILENO);
+       if (fd < 0){
+               return -1;
+       }
+       lc->stdout_orig = fd;
+
+       fd = dup(STDERR_FILENO);
+       if (fd < 0){
+               return -1;
+       }
+       lc->stderr_orig = fd;
+
        lc->log_level = log_level;
        if (!logfile || !logfile[0]) {
-               lc->logfile = stderr;
+               lc->logfile = lc->stderr_orig;
                return 0;
        }
 
        strncpy(lc->filename, logfile, MAX_LOGFILE_LEN);
        lc->filename[MAX_LOGFILE_LEN - 1] = 0;
-       file = fopen(lc->filename, "a");
-       if (!file) {
-               lc->logfile = stderr;
+       fd = open(lc->filename, O_WRONLY|O_CREAT|O_APPEND, S_IRUSR|S_IWUSR);
+       if (fd < 1){
+               lc->logfile = lc->stderr_orig;
                return -1;
        }
-       lc->logfile = file;
+       lc->logfile = fd;
 
-       if (flags & REDIRECT_STDOUT)
-               if (!freopen(lc->filename, "a", stdout))
+       if (flags & REDIRECT_STDOUT){
+               fd = dup2(lc->logfile, STDOUT_FILENO);
+               if (fd < 0)
                        return -1;
-       if (flags & REDIRECT_STDERR)
-               if (!freopen(lc->filename, "a", stderr))
+       }
+       if (flags & REDIRECT_STDERR){
+               fd = dup2(lc->logfile, STDERR_FILENO);
+               if (fd < 0)
                        return -1;
+       }
        lc->flags = flags;
 
        return 0;
@@ -209,6 +237,9 @@ void __xseg_log2(struct log_ctx *lc, enum log_level level, char *fmt, ...)
        char timebuf[1024], buffer[4096];
        char *buf = buffer;
        char *t = NULL, *pn = NULL;
+       ssize_t r, sum;
+       size_t count;
+       int fd;
 
        va_start(ap, fmt);
        switch (level) {
@@ -235,8 +266,21 @@ void __xseg_log2(struct log_ctx *lc, enum log_level level, char *fmt, ...)
                buf = buffer + sizeof(buffer) - 2;/* enough to hold \n and \0 */
        buf += sprintf(buf, "\n");
 
-       fprintf(lc->logfile, "%s", buffer);
-       fflush(lc->logfile);
+       count = buf-buffer;
+       sum = 0;
+       r = 0;
+       fd = *(volatile int *)&lc->logfile;
+       do {
+               r = write(fd, buffer + sum, count - sum);
+               if (r < 0){
+                       if (errno == EBADF)
+                               fd = *(volatile int *)&lc->logfile;
+                       else
+                               //XSEGLOG("Error while writing log");
+                               break;
+               }
+               sum += r;
+       } while (sum < count);
        va_end(ap);
 
        return;