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Unverified Commit 91bc7fb0 by Christian Brauner
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confile: improve strprint()

POSIX specifies [1]: "If the value of n is zero on a call to snprintf(), nothing shall be written, the number of bytes that would have been written had n been sufficiently large excluding the terminating null shall be returned, and s may be a null pointer." But in case there are any non-sane libcs out there that do actually dereference the buffer when when 0 is passed as length to snprintf() let's give them a dummy buffer. [1]: The Open Group Base Specifications Issue 7, 2018 edition IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008) Copyright © 2001-2018 IEEE and The Open Group Signed-off-by: 's avatarChristian Brauner <christian.brauner@ubuntu.com> Reported-by: 's avatarDonghwa Jeong <dh48.jeong@samsung.com>
parent dfd8ceba
Showing with 18 additions and 15 deletions
src/lxc/confile_utils.h
......@@ -41,21 +41,24 @@
#define MACVLAN_MODE_PASSTHRU 8
#endif
#define strprint(str, inlen, ...) \
do { \
len = snprintf(str, inlen, ##__VA_ARGS__); \
if (len < 0) { \
SYSERROR("failed to create string"); \
return -1; \
}; \
fulllen += len; \
if (inlen > 0) { \
if (str) \
str += len; \
inlen -= len; \
if (inlen < 0) \
inlen = 0; \
} \
#define strprint(str, inlen, ...) \
do { \
if (str) \
len = snprintf(str, inlen, ##__VA_ARGS__); \
else \
len = snprintf((char *){""}, 0, ##__VA_ARGS__); \
if (len < 0) { \
SYSERROR("failed to create string"); \
return -1; \
}; \
fulllen += len; \
if (inlen > 0) { \
if (str) \
str += len; \
inlen -= len; \
if (inlen < 0) \
inlen = 0; \
} \
} while (0);
extern int parse_idmaps(const char *idmap, char *type, unsigned long *nsid,
......
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