diff options
Diffstat (limited to 'support/support_descriptors.c')
| -rw-r--r-- | support/support_descriptors.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/support/support_descriptors.c b/support/support_descriptors.c new file mode 100644 index 0000000000..d66cf55080 --- /dev/null +++ b/support/support_descriptors.c @@ -0,0 +1,274 @@ +/* Monitoring file descriptor usage. + Copyright (C) 2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <dirent.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <sys/stat.h> +#include <sys/sysmacros.h> +#include <xunistd.h> + +struct procfs_descriptor +{ + int fd; + char *link_target; + dev_t dev; + ino64_t ino; +}; + +/* Used with qsort. */ +static int +descriptor_compare (const void *l, const void *r) +{ + const struct procfs_descriptor *left = l; + const struct procfs_descriptor *right = r; + /* Cannot overflow due to limited file descriptor range. */ + return left->fd - right->fd; +} + +#define DYNARRAY_STRUCT descriptor_list +#define DYNARRAY_ELEMENT struct procfs_descriptor +#define DYNARRAY_PREFIX descriptor_list_ +#define DYNARRAY_ELEMENT_FREE(e) free ((e)->link_target) +#define DYNARRAY_INITIAL_SIZE 0 +#include <malloc/dynarray-skeleton.c> + +struct support_descriptors +{ + struct descriptor_list list; +}; + +struct support_descriptors * +support_descriptors_list (void) +{ + struct support_descriptors *result = xmalloc (sizeof (*result)); + descriptor_list_init (&result->list); + + DIR *fds = opendir ("/proc/self/fd"); + if (fds == NULL) + FAIL_EXIT1 ("opendir (\"/proc/self/fd\"): %m"); + + while (true) + { + errno = 0; + struct dirent64 *e = readdir64 (fds); + if (e == NULL) + { + if (errno != 0) + FAIL_EXIT1 ("readdir: %m"); + break; + } + + if (e->d_name[0] == '.') + continue; + + char *endptr; + long int fd = strtol (e->d_name, &endptr, 10); + if (*endptr != '\0' || fd < 0 || fd > INT_MAX) + FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s", + e->d_name); + + /* Skip the descriptor which is used to enumerate the + descriptors. */ + if (fd == dirfd (fds)) + continue; + + char *target; + { + char *path = xasprintf ("/proc/self/fd/%ld", fd); + target = xreadlink (path); + free (path); + } + struct stat64 st; + if (fstat64 (fd, &st) != 0) + FAIL_EXIT1 ("readdir: fstat64 (%ld) failed: %m", fd); + + struct procfs_descriptor *item = descriptor_list_emplace (&result->list); + if (item == NULL) + FAIL_EXIT1 ("descriptor_list_emplace: %m"); + item->fd = fd; + item->link_target = target; + item->dev = st.st_dev; + item->ino = st.st_ino; + } + + closedir (fds); + + /* Perform a merge join between descrs and current. This assumes + that the arrays are sorted by file descriptor. */ + + qsort (descriptor_list_begin (&result->list), + descriptor_list_size (&result->list), + sizeof (struct procfs_descriptor), descriptor_compare); + + return result; +} + +void +support_descriptors_free (struct support_descriptors *descrs) +{ + descriptor_list_free (&descrs->list); + free (descrs); +} + +void +support_descriptors_dump (struct support_descriptors *descrs, + const char *prefix, FILE *fp) +{ + struct procfs_descriptor *end = descriptor_list_end (&descrs->list); + for (struct procfs_descriptor *d = descriptor_list_begin (&descrs->list); + d != end; ++d) + { + char *quoted = support_quote_string (d->link_target); + fprintf (fp, "%s%d: target=\"%s\" major=%lld minor=%lld ino=%lld\n", + prefix, d->fd, quoted, + (long long int) major (d->dev), + (long long int) minor (d->dev), + (long long int) d->ino); + free (quoted); + } +} + +static void +dump_mismatch (bool *first, + struct support_descriptors *descrs, + struct support_descriptors *current) +{ + if (*first) + *first = false; + else + return; + + puts ("error: Differences found in descriptor set"); + puts ("Reference descriptor set:"); + support_descriptors_dump (descrs, " ", stdout); + puts ("Current descriptor set:"); + support_descriptors_dump (current, " ", stdout); + puts ("Differences:"); +} + +static void +report_closed_descriptor (bool *first, + struct support_descriptors *descrs, + struct support_descriptors *current, + struct procfs_descriptor *left) +{ + support_record_failure (); + dump_mismatch (first, descrs, current); + printf ("error: descriptor %d was closed\n", left->fd); +} + +static void +report_opened_descriptor (bool *first, + struct support_descriptors *descrs, + struct support_descriptors *current, + struct procfs_descriptor *right) +{ + support_record_failure (); + dump_mismatch (first, descrs, current); + char *quoted = support_quote_string (right->link_target); + printf ("error: descriptor %d was opened (\"%s\")\n", right->fd, quoted); + free (quoted); +} + +void +support_descriptors_check (struct support_descriptors *descrs) +{ + struct support_descriptors *current = support_descriptors_list (); + + /* Perform a merge join between descrs and current. This assumes + that the arrays are sorted by file descriptor. */ + + struct procfs_descriptor *left = descriptor_list_begin (&descrs->list); + struct procfs_descriptor *left_end = descriptor_list_end (&descrs->list); + struct procfs_descriptor *right = descriptor_list_begin (¤t->list); + struct procfs_descriptor *right_end = descriptor_list_end (¤t->list); + + bool first = true; + while (left != left_end && right != right_end) + { + if (left->fd == right->fd) + { + if (strcmp (left->link_target, right->link_target) != 0) + { + support_record_failure (); + char *left_quoted = support_quote_string (left->link_target); + char *right_quoted = support_quote_string (right->link_target); + dump_mismatch (&first, descrs, current); + printf ("error: descriptor %d changed from \"%s\" to \"%s\"\n", + left->fd, left_quoted, right_quoted); + free (left_quoted); + free (right_quoted); + } + if (left->dev != right->dev) + { + support_record_failure (); + dump_mismatch (&first, descrs, current); + printf ("error: descriptor %d changed device" + " from %lld:%lld to %lld:%lld\n", + left->fd, + (long long int) major (left->dev), + (long long int) minor (left->dev), + (long long int) major (right->dev), + (long long int) minor (right->dev)); + } + if (left->ino != right->ino) + { + support_record_failure (); + dump_mismatch (&first, descrs, current); + printf ("error: descriptor %d changed ino from %lld to %lld\n", + left->fd, + (long long int) left->ino, (long long int) right->ino); + } + ++left; + ++right; + } + else if (left->fd < right->fd) + { + /* Gap on the right. */ + report_closed_descriptor (&first, descrs, current, left); + ++left; + } + else + { + /* Gap on the left. */ + TEST_VERIFY_EXIT (left->fd > right->fd); + report_opened_descriptor (&first, descrs, current, right); + ++right; + } + } + + while (left != left_end) + { + /* Closed descriptors (more descriptors on the left). */ + report_closed_descriptor (&first, descrs, current, left); + ++left; + } + + while (right != right_end) + { + /* Opened descriptors (more descriptors on the right). */ + report_opened_descriptor (&first, descrs, current, right); + ++right; + } + + support_descriptors_free (current); +} |