proc-status.patch

   1 From f359c6ee179aad5e077711c188fc8422106cbead Mon Sep 17 00:00:00 2001
   2 From: Aki Tuomi <aki.tuomi@open-xchange.com>
   3 Date: Tue, 21 Mar 2023 08:55:55 +0200
   4 Subject: [PATCH 1/3] lib: process-stat - Use buffer_append_full_istream() to
   5  read files
   6
   7 ---
   8  src/lib/process-stat.c | 84 ++++++++++++++++++++++--------------------
   9  1 file changed, 44 insertions(+), 40 deletions(-)
  10
  11 diff --git a/src/lib/process-stat.c b/src/lib/process-stat.c
  12 index 782503e60b..60eddbc3ec 100644
  13 --- a/src/lib/process-stat.c
  14 +++ b/src/lib/process-stat.c
  15 @@ -1,6 +1,9 @@
  16  /* Copyright (c) 2008-2021 Dovecot authors, see the included COPYING file */
  17
  18  #include "lib.h"
  19 +#include "buffer.h"
  20 +#include "str.h"
  21 +#include "istream.h"
  22  #include "process-stat.h"
  23  #include "time-util.h"
  24  #include <limits.h>
  25 @@ -12,8 +15,12 @@
  26  #include <stdio.h>
  27
  28  #define PROC_STAT_PATH "/proc/self/stat"
  29 +#define PROC_STAT_MAX_SIZE 1024
  30  #define PROC_STATUS_PATH "/proc/self/status"
  31 +#define PROC_STATUS_MAX_SIZE 2048
  32  #define PROC_IO_PATH "/proc/self/io"
  33 +#define PROC_IO_MAX_SIZE 1024
  34 +#define PROC_BUFFER_INITIAL_SIZE 512
  35
  36  static const uint64_t stat_undefined = 0xFFFFFFFFFFFFFFFF;
  37
  38 @@ -71,39 +78,38 @@ static int open_fd(const char *path, struct event *event)
  39  }
  40
  41  static int
  42 -read_file(int fd, const char *path, char *buf_r, size_t buf_size, struct event *event)
  43 +read_file_buffer(const char *path, string_t *buf, size_t max_size, struct event *event)
  44  {
  45 -       ssize_t ret;
  46 -       ret = read(fd, buf_r, buf_size);
  47 -       if (ret <= 0) {
  48 -               if (ret == -1)
  49 -                       e_error(event, "read(%s) failed: %m", path);
  50 -               else
  51 -                       e_error(event, "read(%s) returned EOF", path);
  52 -       } else if (ret == (ssize_t)buf_size) {
  53 -               e_error(event, "%s is larger than expected", path);
  54 -               buf_r[buf_size - 1] = '\0';
  55 -       } else {
  56 -               buf_r[ret] = '\0';
  57 +       const char *error;
  58 +       int fd = open_fd(path, event);
  59 +       if (fd < 0)
  60 +               return -1;
  61 +       struct istream *is = i_stream_create_fd_autoclose(&fd, max_size);
  62 +       i_stream_set_name(is, path);
  63 +       enum buffer_append_result res =
  64 +               buffer_append_full_istream(buf, is, max_size, &error);
  65 +       i_stream_unref(&is);
  66 +       if (res == BUFFER_APPEND_READ_MAX_SIZE)
  67 +               e_error(event, "%s is larger than expected (%zu)", path, max_size);
  68 +       else if (res != BUFFER_APPEND_OK) {
  69 +               e_error(event, "read(%s) failed: %s", path, error);
  70 +               return -1;
  71         }
  72 -       i_close_fd(&fd);
  73 -       return ret <= 0 ? -1 : 0;
  74 +       return 0;
  75  }
  76
  77  static int parse_key_val_file(const char *path,
  78 +                             size_t max_size,
  79                               struct key_val *fields,
  80                               struct event *event)
  81  {
  82 -       char buf[2048];
  83 -       int fd;
  84 -
  85 -       fd = open_fd(path, event);
  86 -       if (fd == -1 || read_file(fd, path, buf, sizeof(buf), event) < 0) {
  87 +       string_t *buf = t_str_new(PROC_BUFFER_INITIAL_SIZE);
  88 +       if (read_file_buffer(path, buf, max_size, event) < 0) {
  89                 for (; fields->key != NULL; fields++)
  90                         *fields->value = stat_undefined;
  91                 return -1;
  92         }
  93 -       buffer_parse(buf, fields);
  94 +       buffer_parse(str_c(buf), fields);
  95         return 0;
  96  }
  97
  98 @@ -117,7 +123,8 @@ static int parse_proc_io(struct process_stat *stat_r, struct event *event)
  99                 { NULL, NULL, 0 },
 100         };
 101         if (stat_r->proc_io_failed ||
 102 -           parse_key_val_file(PROC_IO_PATH, fields, event) < 0) {
 103 +           parse_key_val_file(PROC_IO_PATH, PROC_IO_MAX_SIZE, fields,
 104 +                              event) < 0) {
 105                 stat_r->proc_io_failed = TRUE;
 106                 return -1;
 107         }
 108 @@ -132,7 +139,8 @@ static int parse_proc_status(struct process_stat *stat_r, struct event *event)
 109                 { NULL, NULL, 0 },
 110         };
 111         if (stat_r->proc_status_failed ||
 112 -           parse_key_val_file(PROC_STATUS_PATH, fields, event) < 0) {
 113 +           parse_key_val_file(PROC_STATUS_PATH, PROC_STATUS_MAX_SIZE,
 114 +                              fields, event) < 0) {
 115                 stat_r->proc_status_failed = TRUE;
 116                 return -1;
 117         }
 118 @@ -156,8 +164,7 @@ static int stat_get_rusage(struct process_stat *stat_r)
 119
 120  static int parse_stat_file(struct process_stat *stat_r, struct event *event)
 121  {
 122 -       int fd = -1;
 123 -       char buf[1024];
 124 +       string_t *buf = t_str_new(PROC_BUFFER_INITIAL_SIZE);
 125         unsigned int i;
 126         const char *const *tmp;
 127         struct {
 128 @@ -171,9 +178,8 @@ static int parse_stat_file(struct process_stat *stat_r, struct event *event)
 129                 { &stat_r->vsz, 22 },
 130                 { &stat_r->rss, 23 },
 131         };
 132 -       if (!stat_r->proc_stat_failed)
 133 -               fd = open_fd(PROC_STAT_PATH, event);
 134 -       if (fd == -1) {
 135 +       if (stat_r->proc_stat_failed ||
 136 +           read_file_buffer(PROC_STAT_PATH, buf, PROC_STAT_MAX_SIZE, event) < 0) {
 137                 stat_r->proc_stat_failed = TRUE;
 138                 /* vsz and rss are not provided by getrusage(), setting to undefined */
 139                 stat_r->vsz = stat_undefined;
 140 @@ -187,11 +193,7 @@ static int parse_stat_file(struct process_stat *stat_r, struct event *event)
 141                 }
 142                 return 0;
 143         }
 144 -       if (read_file(fd, PROC_STAT_PATH, buf, sizeof(buf), event) < 0) {
 145 -               stat_r->proc_stat_failed = TRUE;
 146 -               return -1;
 147 -       }
 148 -       tmp = t_strsplit(buf, " ");
 149 +       tmp = t_strsplit(str_c(buf), " ");
 150         unsigned int tmp_count = str_array_length(tmp);
 151
 152         for (i = 0; i < N_ELEMENTS(fields); i++) {
 153 @@ -208,13 +210,15 @@ static int parse_all_stats(struct process_stat *stat_r, struct event *event)
 154  {
 155         bool has_fields = FALSE;
 156
 157 -       if (parse_stat_file(stat_r, event) == 0)
 158 -               has_fields = TRUE;
 159 -       if (parse_proc_io(stat_r, event) == 0)
 160 -               has_fields = TRUE;
 161 -       if ((!stat_r->proc_stat_failed || stat_r->rusage_failed) &&
 162 -           parse_proc_status(stat_r, event) == 0)
 163 -               has_fields = TRUE;
 164 +       T_BEGIN {
 165 +               if (parse_stat_file(stat_r, event) == 0)
 166 +                       has_fields = TRUE;
 167 +               if (parse_proc_io(stat_r, event) == 0)
 168 +                       has_fields = TRUE;
 169 +               if ((!stat_r->proc_stat_failed || stat_r->rusage_failed) &&
 170 +                   parse_proc_status(stat_r, event) == 0)
 171 +                       has_fields = TRUE;
 172 +       } T_END;
 173
 174         if (has_fields)
 175                 return 0;
 176
 177 From 218a79a48bb0e5d2be44bb46c51836fd406b0c50 Mon Sep 17 00:00:00 2001
 178 From: Aki Tuomi <aki.tuomi@open-xchange.com>
 179 Date: Tue, 21 Mar 2023 09:05:12 +0200
 180 Subject: [PATCH 2/3] lib: process-stat - Increase maximum /proc/self/status
 181  size
 182
 183 Kernel 6.x has larger status file.
 184 ---
 185  src/lib/process-stat.c | 2 +-
 186  1 file changed, 1 insertion(+), 1 deletion(-)
 187
 188 diff --git a/src/lib/process-stat.c b/src/lib/process-stat.c
 189 index 60eddbc3ec..1d23c89964 100644
 190 --- a/src/lib/process-stat.c
 191 +++ b/src/lib/process-stat.c
 192 @@ -17,7 +17,7 @@
 193  #define PROC_STAT_PATH "/proc/self/stat"
 194  #define PROC_STAT_MAX_SIZE 1024
 195  #define PROC_STATUS_PATH "/proc/self/status"
 196 -#define PROC_STATUS_MAX_SIZE 2048
 197 +#define PROC_STATUS_MAX_SIZE 4096
 198  #define PROC_IO_PATH "/proc/self/io"
 199  #define PROC_IO_MAX_SIZE 1024
 200  #define PROC_BUFFER_INITIAL_SIZE 512
 201
 202 From d93c31d51b05d43eaa6eeef9cdc0f7a4157f7d0e Mon Sep 17 00:00:00 2001
 203 From: Aki Tuomi <aki.tuomi@open-xchange.com>
 204 Date: Tue, 21 Mar 2023 09:13:35 +0200
 205 Subject: [PATCH 3/3] lib: process-stat - Use eacces_error_get() for EACCES
 206  errno
 207
 208 This tells better why the open failed.
 209 ---
 210  src/lib/process-stat.c | 5 ++++-
 211  1 file changed, 4 insertions(+), 1 deletion(-)
 212
 213 diff --git a/src/lib/process-stat.c b/src/lib/process-stat.c
 214 index 1d23c89964..454d9335d2 100644
 215 --- a/src/lib/process-stat.c
 216 +++ b/src/lib/process-stat.c
 217 @@ -4,6 +4,7 @@
 218  #include "buffer.h"
 219  #include "str.h"
 220  #include "istream.h"
 221 +#include "eacces-error.h"
 222  #include "process-stat.h"
 223  #include "time-util.h"
 224  #include <limits.h>
 225 @@ -69,8 +70,10 @@ static int open_fd(const char *path, struct event *event)
 226                 errno = EACCES;
 227         }
 228         if (fd == -1) {
 229 -               if (errno == ENOENT || errno == EACCES)
 230 +               if (errno == ENOENT)
 231                         e_debug(event, "open(%s) failed: %m", path);
 232 +               else if (errno == EACCES)
 233 +                       e_debug(event, "%s", eacces_error_get("open", path));
 234                 else
 235                         e_error(event, "open(%s) failed: %m", path);
 236         }