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syscall-dump: add lseek/lseek64 wrappers, add log write loop, keep errno

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This commit is contained in:
Jaroslav Kysela 2015-04-03 12:33:08 +02:00
parent 408661e70a
commit a1e4e496bc
1 changed files with 53 additions and 3 deletions
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54
tools/syscall-dump.c
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@ -11,6 +11,7 @@ Usage:
*/
#define _LARGEFILE64_SOURCE
#include <dlfcn.h>
#include <sys/types.h>
#include <sys/ioctl.h>
@ -37,6 +38,8 @@ static int (*real_open64)(const char *pathname, int flags, ...);
static int (*real_ioctl)(int fd, unsigned long request, ...);
static ssize_t (*real_write)(int fd, const void *buf, size_t len);
static ssize_t (*real_read)(int fd, void *buf, size_t len);
static off_t (*real_lseek)(int fd, off_t offset, int whence);
static off64_t (*real_lseek64)(int fd, off64_t offset, int whence);
static int (*real_close)(int fd);
#define REDIR(realptr, symname) do { \
@ -51,8 +54,11 @@ static int (*real_close)(int fd);
/* log function */
static void dlog(const char *fmt, ...)
{
char buf[2048];
char buf[2048], *b;
va_list ap;
size_t len;
ssize_t r;
int keep_errno = errno;
if (dlog_fd < 0) {
const char *f = getenv("SYSCALL_DUMP_LOG");
@ -64,13 +70,25 @@ static void dlog(const char *fmt, ...)
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
REDIR(real_write, "write");
real_write(dlog_fd, buf, strlen(buf));
len = strlen(b = buf);
while (len > 0) {
r = real_write(dlog_fd, b, len);
if (r < 0) {
if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK)
break;
} else {
len -= r;
b += r;
}
}
errno = keep_errno;
}
static void dlog_hexa(const char *prefix, void *buf, size_t len)
{
char b[128];
size_t i, l;
int keep_errno = errno;
while (len > 0) {
for (i = l = 0; i < 16 && len > 0; i++, len--, buf++)
@ -79,6 +97,7 @@ static void dlog_hexa(const char *prefix, void *buf, size_t len)
b[l+1] = '\0';
dlog("%s %s", prefix, b);
}
errno = keep_errno;
}
/* open() wrapper */
@ -149,7 +168,12 @@ ssize_t write(int fd, const void *buf, size_t len)
REDIR(real_write, "write");
r = real_write(fd, buf, len);
if (r > 0) {
dlog_hexa("write:", (void *)buf, r);
dlog(" write(%d, %p, %zd) = %d (%d)\n", fd, buf, len, r, E(r));
} else {
dlog("write(%d, %p, %zd) = %d (%d)\n", fd, buf, len, r, E(r));
}
return r;
}
@ -167,6 +191,32 @@ ssize_t read(int fd, void *buf, size_t len)
return r;
}
/* lseek() wrapper */
off_t lseek(int fd, off_t offset, int whence)
{
int r;
REDIR(real_lseek, "lseek");
r = real_lseek(fd, offset, whence);
dlog("lseek(%d, %lx, %d) = %d (%d)\n", fd, (long)offset, whence, r, E(r));
return r;
}
/* lseek64() wrapper */
off64_t lseek64(int fd, off64_t offset, int whence)
{
int r;
REDIR(real_lseek64, "lseek64");
r = real_lseek64(fd, offset, whence);
dlog("lseek(%d, %llx, %d) = %d (%d)\n", fd, (long long)offset, whence, r, E(r));
return r;
}
/* ioctl() wrapper */
int ioctl(int fd, unsigned long request, ...)
{