initutils: remove fgets() from setproctitle()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/initutils.c b/src/lxc/initutils.c
index d8c00c587d4659b9e9a248591da1c1f122f03d13..a55d8b2860d622acae041c31e80d29bee88f6c59 100644 (file)
--- a/src/lxc/initutils.c
+++ b/src/lxc/initutils.c
@@ -240,62 +240,64 @@ out:
  */
 int setproctitle(char *title)
 {
+       __do_fclose FILE *f = NULL;
+       int i, fd, len;
+       char *buf_ptr;
+       char buf[LXC_LINELEN];
+       int ret = 0;
+       ssize_t bytes_read = 0;
        static char *proctitle = NULL;
-       char buf[2048], *tmp;
-       FILE *f;
-       int i, len, ret = 0;
 
-       /* We don't really need to know all of this stuff, but unfortunately
+       /*
+        * We don't really need to know all of this stuff, but unfortunately
         * PR_SET_MM_MAP requires us to set it all at once, so we have to
         * figure it out anyway.
         */
        unsigned long start_data, end_data, start_brk, start_code, end_code,
-                       start_stack, arg_start, arg_end, env_start, env_end,
-                       brk_val;
+           start_stack, arg_start, arg_end, env_start, env_end, brk_val;
        struct prctl_mm_map prctl_map;
 
        f = fopen_cloexec("/proc/self/stat", "r");
-       if (!f) {
+       if (!f)
                return -1;
-       }
 
-       tmp = fgets(buf, sizeof(buf), f);
-       fclose(f);
-       if (!tmp) {
+       fd = fileno(f);
+       if (fd < 0)
                return -1;
-       }
+
+       bytes_read = lxc_read_nointr(fd, buf, sizeof(buf) - 1);
+       if (bytes_read <= 0)
+               return -1;
+
+       buf[bytes_read] = '\0';
 
        /* Skip the first 25 fields, column 26-28 are start_code, end_code,
         * and start_stack */
-       tmp = strchr(buf, ' ');
+       buf_ptr = strchr(buf, ' ');
        for (i = 0; i < 24; i++) {
-               if (!tmp)
+               if (!buf_ptr)
                        return -1;
-               tmp = strchr(tmp+1, ' ');
+               buf_ptr = strchr(buf_ptr + 1, ' ');
        }
-       if (!tmp)
+       if (!buf_ptr)
                return -1;
 
-       i = sscanf(tmp, "%lu %lu %lu", &start_code, &end_code, &start_stack);
+       i = sscanf(buf_ptr, "%lu %lu %lu", &start_code, &end_code, &start_stack);
        if (i != 3)
                return -1;
 
        /* Skip the next 19 fields, column 45-51 are start_data to arg_end */
        for (i = 0; i < 19; i++) {
-               if (!tmp)
+               if (!buf_ptr)
                        return -1;
-               tmp = strchr(tmp+1, ' ');
+               buf_ptr = strchr(buf_ptr + 1, ' ');
        }
 
-       if (!tmp)
+       if (!buf_ptr)
                return -1;
 
-       i = sscanf(tmp, "%lu %lu %lu %*u %*u %lu %lu",
-               &start_data,
-               &end_data,
-               &start_brk,
-               &env_start,
-               &env_end);
+       i = sscanf(buf_ptr, "%lu %lu %lu %*u %*u %lu %lu", &start_data,
+                  &end_data, &start_brk, &env_start, &env_end);
        if (i != 5)
                return -1;
 
@@ -307,32 +309,32 @@ int setproctitle(char *title)
        if (!proctitle)
                return -1;
 
-       arg_start = (unsigned long) proctitle;
+       arg_start = (unsigned long)proctitle;
        arg_end = arg_start + len;
 
        brk_val = syscall(__NR_brk, 0);
 
-       prctl_map = (struct prctl_mm_map) {
-               .start_code = start_code,
-               .end_code = end_code,
-               .start_stack = start_stack,
-               .start_data = start_data,
-               .end_data = end_data,
-               .start_brk = start_brk,
-               .brk = brk_val,
-               .arg_start = arg_start,
-               .arg_end = arg_end,
-               .env_start = env_start,
-               .env_end = env_end,
-               .auxv = NULL,
-               .auxv_size = 0,
-               .exe_fd = -1,
+       prctl_map = (struct prctl_mm_map){
+           .start_code = start_code,
+           .end_code = end_code,
+           .start_stack = start_stack,
+           .start_data = start_data,
+           .end_data = end_data,
+           .start_brk = start_brk,
+           .brk = brk_val,
+           .arg_start = arg_start,
+           .arg_end = arg_end,
+           .env_start = env_start,
+           .env_end = env_end,
+           .auxv = NULL,
+           .auxv_size = 0,
+           .exe_fd = -1,
        };
 
        ret = prctl(PR_SET_MM, prctl_arg(PR_SET_MM_MAP), prctl_arg(&prctl_map),
                    prctl_arg(sizeof(prctl_map)), prctl_arg(0));
        if (ret == 0)
-               (void)strlcpy((char*)arg_start, title, len);
+               (void)strlcpy((char *)arg_start, title, len);
        else
                SYSWARN("Failed to set cmdline");