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wrap fgets to retry on EINTR

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The read() underlying fgets() can be interrupted by a signal handler
causing fgets() to return NULL.  Before we started handling SIGWINCH,
the odds of interrupting a read were low and typically resulted in
termination anyway.  Replace all fgets calls with a wrapper that retries
in EINTR.

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
This commit is contained in:
Andrew Gregory 2014-08-06 16:36:00 -04:00 • committed by Allan McRae
parent 9c066dff43
commit c792262b13
7 changed files with 43 additions and 14 deletions
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14
lib/libalpm/be_local.c
View file

@ -616,7 +616,7 @@ char *_alpm_local_db_pkgpath(alpm_db_t *db, alpm_pkg_t *info,
}
#define READ_NEXT() do { \
if(fgets(line, sizeof(line), fp) == NULL && !feof(fp)) goto error; \
if(safe_fgets(line, sizeof(line), fp) == NULL && !feof(fp)) goto error; \
_alpm_strip_newline(line, 0); \
} while(0)
@ -627,7 +627,7 @@ char *_alpm_local_db_pkgpath(alpm_db_t *db, alpm_pkg_t *info,
#define READ_AND_STORE_ALL(f) do { \
char *linedup; \
if(fgets(line, sizeof(line), fp) == NULL) {\
if(safe_fgets(line, sizeof(line), fp) == NULL) {\
if(!feof(fp)) goto error; else break; \
} \
if(_alpm_strip_newline(line, 0) == 0) break; \
@ -636,7 +636,7 @@ char *_alpm_local_db_pkgpath(alpm_db_t *db, alpm_pkg_t *info,
} while(1) /* note the while(1) and not (0) */
#define READ_AND_SPLITDEP(f) do { \
if(fgets(line, sizeof(line), fp) == NULL) {\
if(safe_fgets(line, sizeof(line), fp) == NULL) {\
if(!feof(fp)) goto error; else break; \
} \
if(_alpm_strip_newline(line, 0) == 0) break; \
@ -682,7 +682,7 @@ static int local_db_read(alpm_pkg_t *info, alpm_dbinfrq_t inforeq)
}
free(path);
while(!feof(fp)) {
if(fgets(line, sizeof(line), fp) == NULL && !feof(fp)) {
if(safe_fgets(line, sizeof(line), fp) == NULL && !feof(fp)) {
goto error;
}
if(_alpm_strip_newline(line, 0) == 0) {
@ -771,13 +771,13 @@ static int local_db_read(alpm_pkg_t *info, alpm_dbinfrq_t inforeq)
goto error;
}
free(path);
while(fgets(line, sizeof(line), fp)) {
while(safe_fgets(line, sizeof(line), fp)) {
_alpm_strip_newline(line, 0);
if(strcmp(line, "%FILES%") == 0) {
size_t files_count = 0, files_size = 0, len;
alpm_file_t *files = NULL;
while(fgets(line, sizeof(line), fp) &&
while(safe_fgets(line, sizeof(line), fp) &&
(len = _alpm_strip_newline(line, 0))) {
if(!_alpm_greedy_grow((void **)&files, &files_size,
(files_size ? files_size + sizeof(alpm_file_t) : 8 * sizeof(alpm_file_t)))) {
@ -797,7 +797,7 @@ static int local_db_read(alpm_pkg_t *info, alpm_dbinfrq_t inforeq)
info->files.count = files_count;
info->files.files = files;
} else if(strcmp(line, "%BACKUP%") == 0) {
while(fgets(line, sizeof(line), fp) && _alpm_strip_newline(line, 0)) {
while(safe_fgets(line, sizeof(line), fp) && _alpm_strip_newline(line, 0)) {
alpm_backup_t *backup;
CALLOC(backup, 1, sizeof(alpm_backup_t), goto error);
if(_alpm_split_backup(line, &backup)) {

2
lib/libalpm/trans.c
View file

@ -280,7 +280,7 @@ static int grep(const char *fn, const char *needle)
}
while(!feof(fp)) {
char line[1024];
if(fgets(line, sizeof(line), fp) == NULL) {
if(safe_fgets(line, sizeof(line), fp) == NULL) {
continue;
}
/* TODO: this will not work if the search string

3
lib/libalpm/util.c
View file

@ -576,8 +576,9 @@ int _alpm_run_chroot(alpm_handle_t *handle, const char *cmd, char *const argv[])
.type = ALPM_EVENT_SCRIPTLET_INFO,
.line = line
};
if(fgets(line, PATH_MAX, pipe_file) == NULL)
if(safe_fgets(line, PATH_MAX, pipe_file) == NULL) {
break;
}
alpm_logaction(handle, "ALPM-SCRIPTLET", "%s", line);
EVENT(handle, &event);
}

25
src/common/util-common.c
View file

@ -17,6 +17,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
@ -102,6 +103,30 @@ int llstat(char *path, struct stat *buf)
return ret;
}
/** Wrapper around fgets() which properly handles EINTR
* @param s string to read into
* @param size maximum length to read
* @param stream stream to read from
* @return value returned by fgets()
*/
char *safe_fgets(char *s, int size, FILE *stream)
{
char *ret;
int errno_save = errno, ferror_save = ferror(stream);
while((ret = fgets(s, size, stream)) == NULL && !feof(stream)) {
if(errno == EINTR) {
/* clear any errors we set and try again */
errno = errno_save;
if(!ferror_save) {
clearerr(stream);
}
} else {
break;
}
}
return ret;
}
#ifndef HAVE_STRNDUP
/* A quick and dirty implementation derived from glibc */
/** Determines the length of a fixed-size string.

3
src/common/util-common.h
View file

@ -20,6 +20,7 @@
#ifndef _PM_UTIL_COMMON_H
#define _PM_UTIL_COMMON_H
#include <stdio.h>
#include <sys/stat.h> /* struct stat */
const char *mbasename(const char *path);
@ -27,6 +28,8 @@ char *mdirname(const char *path);
int llstat(char *path, struct stat *buf);
char *safe_fgets(char *s, int size, FILE *stream);
#ifndef HAVE_STRNDUP
char *strndup(const char *s, size_t n);
#endif

2
src/pacman/ini.c
View file

@ -66,7 +66,7 @@ static int _parse_ini(const char *file, ini_parser_fn cb, void *data,
goto cleanup;
}
while(fgets(line, PATH_MAX, fp)) {
while(safe_fgets(line, PATH_MAX, fp)) {
char *key, *value, *ptr;
size_t line_len;

8
src/pacman/util.c
View file

@ -1403,7 +1403,7 @@ int multiselect_question(char *array, int count)
flush_term_input(fileno(stdin));
if(fgets(response, response_len, stdin)) {
if(safe_fgets(response, response_len, stdin)) {
const size_t response_incr = 64;
size_t len;
/* handle buffer not being large enough to read full line case */
@ -1416,7 +1416,7 @@ int multiselect_question(char *array, int count)
lastchar = response + response_len - 1;
/* sentinel byte */
*lastchar = 1;
if(fgets(response + response_len - response_incr - 1,
if(safe_fgets(response + response_len - response_incr - 1,
response_incr + 1, stdin) == 0) {
free(response);
return -1;
@ -1467,7 +1467,7 @@ int select_question(int count)
flush_term_input(fileno(stdin));
if(fgets(response, sizeof(response), stdin)) {
if(safe_fgets(response, sizeof(response), stdin)) {
size_t len = strtrim(response);
if(len > 0) {
int n;
@ -1521,7 +1521,7 @@ static int question(short preset, const char *format, va_list args)
flush_term_input(fd_in);
if(fgets(response, sizeof(response), stdin)) {
if(safe_fgets(response, sizeof(response), stdin)) {
size_t len = strtrim(response);
if(len == 0) {
return preset;