BUG/MAJOR: stats-file: ensure shm_stats_file_object struct mapping consistency

As reported by @tianon on GH #3168, running haproxy on 32bits i386
platform would trigger the following BUG_ON() statement:

 FATAL: bug condition "sizeof(struct shm_stats_file_object) != 544" matched at src/stats-file.c:825
shm_stats_file_object struct size changed, is is part of the exported API: ensure all precautions were taken (ie: shm_stats_file version change) before adjusting this

In fact, some efforts were already taken to ensure shm_stats_file_object
struct size remains consistent on 64 vs 32 bits platforms, since
shm_stats_file_object is part of the public API and directly exposed in
the stats file.

However, some parts were overlooked: some structs that are embedded in
shm_stats_file_object struct itself weren't using fixed-width integers,
and would sometime be unaligned. The result of this is that it was
up to the compiler (platform-dependent) to choose how to deal with such
ambiguities, which could cause the struct mapping/size to be inconsistent
from one platform to another.

Hopefully this was caught by the BUG_ON() statement and with the precious
help of @tianon

To fix this, we now use fixed-width integers everywhere for members
(and submembers) of shm_stats_file_object struct, and we use explicit
padding where missing to avoid automatic padding when we don't expect
one. As for the previous commit, we leverage FIXED_SIZE() and
FIXED_SIZE_ARRAY() macro to set the expected width for each integer
without causing build issues on platform that don't support larger
integers.

No backport needed, this feature was introduced during 3.3-dev.

diff --git a/include/haproxy/counters-t.h b/include/haproxy/counters-t.h
index 13dd8f88a39d084301ab23de1df190b67e920386..5ea153cf48fb774c9b97860196f0ecf28da3f988 100644 (file)
--- a/include/haproxy/counters-t.h
+++ b/include/haproxy/counters-t.h
@@ -40,22 +40,23 @@
  */
 #define COUNTERS_SHARED_TG                                                           \
        struct {                                                                     \
-               unsigned long last_state_change;        /* last time, when the state was changed */\
-               long long srv_aborts;                   /* aborted responses during DATA phase caused by the server */\
-               long long cli_aborts;                   /* aborted responses during DATA phase caused by the client */\
-               long long internal_errors;              /* internal processing errors */\
-               long long failed_rewrites;              /* failed rewrites (warning) */\
-               long long bytes_out;                    /* number of bytes transferred from the server to the client */\
-               long long bytes_in;                     /* number of bytes transferred from the client to the server */\
-               long long denied_resp;                  /* blocked responses because of security concerns */\
-               long long denied_req;                   /* blocked requests because of security concerns */\
-               long long    cum_sess;                  /* cumulated number of accepted connections */\
+               FIXED_SIZE(8, unsigned long, last_state_change); /* last time, when the state was changed */\
+               FIXED_SIZE(8, long long, srv_aborts);            /* aborted responses during DATA phase caused by the server */\
+               FIXED_SIZE(8, long long, cli_aborts);            /* aborted responses during DATA phase caused by the client */\
+               FIXED_SIZE(8, long long, internal_errors);       /* internal processing errors */\
+               FIXED_SIZE(8, long long, failed_rewrites);       /* failed rewrites (warning) */\
+               FIXED_SIZE(8, long long, bytes_out);             /* number of bytes transferred from the server to the client */\
+               FIXED_SIZE(8, long long, bytes_in);              /* number of bytes transferred from the client to the server */\
+               FIXED_SIZE(8, long long, denied_resp);           /* blocked responses because of security concerns */\
+               FIXED_SIZE(8, long long, denied_req);            /* blocked requests because of security concerns */\
+               FIXED_SIZE(8, long long, cum_sess);              /* cumulated number of accepted connections */\
                /* compression counters, index 0 for requests, 1 for responses */\
-               long long comp_in[2];                   /* input bytes fed to the compressor */\
-               long long comp_out[2];                  /* output bytes emitted by the compressor */\
-               long long comp_byp[2];                  /* input bytes that bypassed the compressor (cpu/ram/bw limitation) */\
-               struct freq_ctr sess_per_sec;           /* sessions per second on this server */\
-       }
+               FIXED_SIZE_ARRAY(8, 2, long long, comp_in);      /* input bytes fed to the compressor */\
+               FIXED_SIZE_ARRAY(8, 2, long long, comp_out);     /* output bytes emitted by the compressor */\
+               FIXED_SIZE_ARRAY(8, 2, long long, comp_byp);     /* input bytes that bypassed the compressor (cpu/ram/bw limitation) */\
+               struct freq_ctr sess_per_sec;                    /* sessions per second on this server */\
+               ALWAYS_PAD(4);                                   /* ensure 4 bytes hole is consistent 32bits vs 64 bits systems */\
+       };
 
 // for convenience (generic pointer)
 struct counters_shared {
@@ -69,30 +70,32 @@ struct counters_shared {
  * /!\ any change performed here will impact shm-stats-file mapping because the
  * struct is embedded in shm_stats_file_object struct, so proceed with caution
  * and change shm stats file version if needed
+ *
+ * fixed width integers should be used
  */
 struct fe_counters_shared_tg {
        COUNTERS_SHARED_TG;
 
-       long long denied_sess;                  /* denied session requests (tcp-req-sess rules) */
-       long long denied_conn;                  /* denied connection requests (tcp-req-conn rules) */
-       long long intercepted_req;              /* number of monitoring or stats requests intercepted by the frontend */
-       long long    cum_conn;                  /* cumulated number of received connections */
-       struct freq_ctr conn_per_sec;           /* received connections per second on the frontend */
+       FIXED_SIZE(8, long long, denied_sess);                      /* denied session requests (tcp-req-sess rules) */
+       FIXED_SIZE(8, long long, denied_conn);                      /* denied connection requests (tcp-req-conn rules) */
+       FIXED_SIZE(8, long long, intercepted_req);                  /* number of monitoring or stats requests intercepted by the frontend */
+       FIXED_SIZE(8, long long, cum_conn);                         /* cumulated number of received connections */
+       struct freq_ctr conn_per_sec;                               /* received connections per second on the frontend */
 
-       struct freq_ctr req_per_sec;            /* HTTP requests per second on the frontend */
+       struct freq_ctr req_per_sec;                                /* HTTP requests per second on the frontend */
 
-       long long    cum_sess_ver[3];           /* cumulated number of h1/h2/h3 sessions */
+       FIXED_SIZE_ARRAY(8, 3, long long, cum_sess_ver);            /* cumulated number of h1/h2/h3 sessions */
        union {
                struct {
-                       long long cum_req[4];   /* cumulated number of processed other/h1/h2/h3 requests */
-                       long long cache_hits;   /* cache hits */
-                       long long cache_lookups;/* cache lookups */
-                       long long comp_rsp;     /* number of compressed responses */
-                       long long rsp[6];       /* http response codes */
+                       FIXED_SIZE_ARRAY(8, 4, long long, cum_req); /* cumulated number of processed other/h1/h2/h3 requests */
+                       FIXED_SIZE(8, long long, cache_hits);       /* cache hits */
+                       FIXED_SIZE(8, long long, cache_lookups);    /* cache lookups */
+                       FIXED_SIZE(8, long long, comp_rsp);         /* number of compressed responses */
+                       FIXED_SIZE_ARRAY(8, 6, long long, rsp);     /* http response codes */
                } http;
-       } p;                                    /* protocol-specific stats */
+       } p;                                                        /* protocol-specific stats */
 
-       long long failed_req;                   /* failed requests (eg: invalid or timeout) */
+       FIXED_SIZE(8, long long, failed_req);                       /* failed requests (eg: invalid or timeout) */
 };
 
 struct fe_counters_shared {
@@ -121,35 +124,36 @@ struct fe_counters {
 /* /!\ any change performed here will impact shm-stats-file mapping because the
  * struct is embedded in shm_stats_file_object struct, so proceed with caution
  * and change shm stats file version if needed
+ *
+ * fixed width integer types should be used
  */
 struct be_counters_shared_tg {
        COUNTERS_SHARED_TG;
 
-       long long  cum_lbconn;                  /* cumulated number of sessions processed by load balancing (BE only) */
+       FIXED_SIZE(8, long long, cum_lbconn);                   /* cumulated number of sessions processed by load balancing (BE only) */
 
-       long long connect;                      /* number of connection establishment attempts */
-       long long reuse;                        /* number of connection reuses */
-       unsigned long last_sess;                /* last session time */
+       FIXED_SIZE(8, long long, connect);                      /* number of connection establishment attempts */
+       FIXED_SIZE(8, long long, reuse);                        /* number of connection reuses */
+       FIXED_SIZE(8, unsigned long, last_sess);                /* last session time */
 
-       long long failed_checks, failed_hana;   /* failed health checks and health analyses for servers */
-       long long down_trans;                   /* up->down transitions */
+       FIXED_SIZE(8, long long, failed_checks);                /* failed health checks */
+       FIXED_SIZE(8, long long, failed_hana);                  /* failed health analyses */
+       FIXED_SIZE(8, long long, down_trans);                   /* up->down transitions */
 
        union {
                struct {
-                       long long cum_req;      /* cumulated number of processed HTTP requests */
-
-                       long long cache_hits;   /* cache hits */
-                       long long cache_lookups;/* cache lookups */
-                       long long comp_rsp;     /* number of compressed responses */
-                       long long rsp[6];       /* http response codes */
-
+                       FIXED_SIZE(8, long long, cum_req);      /* cumulated number of processed HTTP requests */
+                       FIXED_SIZE(8, long long, cache_hits);   /* cache hits */
+                       FIXED_SIZE(8, long long, cache_lookups);/* cache lookups */
+                       FIXED_SIZE(8, long long, comp_rsp);     /* number of compressed responses */
+                       FIXED_SIZE_ARRAY(8, 6, long long, rsp); /* http response codes */
                } http;
-       } p;                                    /* protocol-specific stats */
+       } p;                                                    /* protocol-specific stats */
 
-       long long redispatches;                 /* retried and redispatched connections (BE only) */
-       long long retries;                      /* retried and redispatched connections (BE only) */
-       long long failed_resp;                  /* failed responses (BE only) */
-       long long failed_conns;                 /* failed connect() attempts (BE only) */
+       FIXED_SIZE(8, long long, redispatches);                 /* retried and redispatched connections (BE only) */
+       FIXED_SIZE(8, long long, retries);                      /* retried and redispatched connections (BE only) */
+       FIXED_SIZE(8, long long, failed_resp);                  /* failed responses (BE only) */
+       FIXED_SIZE(8, long long, failed_conns);                 /* failed connect() attempts (BE only) */
 };
 
 struct be_counters_shared {