libexplain  1.4.D001
Functions
libexplain/setuid.c File Reference
#include <libexplain/ac/errno.h>
#include <libexplain/ac/unistd.h>
#include <libexplain/buffer/errno/setuid.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/setuid.h>

Go to the source code of this file.

Functions

const char * explain_setuid (int uid)
const char * explain_errno_setuid (int errnum, int uid)
void explain_message_setuid (char *message, int message_size, int uid)
void explain_message_errno_setuid (char *message, int message_size, int errnum, int uid)

Function Documentation

const char* explain_errno_setuid ( int  errnum,
int  uid 
)

The explain_errno_setuid function is used to obtain an explanation of an error returned by the setuid(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

Parameters:
errnumThe error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
uidThe original uid, exactly as passed to the setuid(2) system call.
Returns:
The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.
Note:
This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.
Example:
This function is intended to be used in a fashion similar to the following example:
 if (setuid(uid) < 0)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_setuid(err, uid));
     exit(EXIT_FAILURE);
 }
The above code example is available pre-packaged as the explain_setuid_or_die function.

Definition at line 35 of file setuid.c.

void explain_message_errno_setuid ( char *  message,
int  message_size,
int  errnum,
int  uid 
)

The explain_message_errno_setuid function is used to obtain an explanation of an error returned by the setuid(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

Parameters:
messageThe location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_sizeThe size in bytes of the location in which to store the returned message.
errnumThe error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
uidThe original uid, exactly as passed to the setuid(2) system call.
Example:
This function is intended to be used in a fashion similar to the following example:
 if (setuid(uid) < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_setuid(message, sizeof(message), err, uid);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }
The above code example is available pre-packaged as the explain_setuid_or_die function.

Definition at line 51 of file setuid.c.

void explain_message_setuid ( char *  message,
int  message_size,
int  uid 
)

The explain_message_setuid function is used to obtain an explanation of an error returned by the setuid(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

Parameters:
messageThe location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_sizeThe size in bytes of the location in which to store the returned message.
uidThe original uid, exactly as passed to the setuid(2) system call.
Example:
This function is intended to be used in a fashion similar to the following example:
 if (setuid(uid) < 0)
 {
     char message[3000];
     explain_message_setuid(message, sizeof(message), uid);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }
The above code example is available pre-packaged as the explain_setuid_or_die function.

Definition at line 44 of file setuid.c.

const char* explain_setuid ( int  uid)

The explain_setuid function is used to obtain an explanation of an error returned by the setuid(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

Parameters:
uidThe original uid, exactly as passed to the setuid(2) system call.
Returns:
The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.
Note:
This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.
Example:
This function is intended to be used in a fashion similar to the following example:
 if (setuid(uid) < 0)
 {
     fprintf(stderr, "%s\n", explain_setuid(uid));
     exit(EXIT_FAILURE);
 }
The above code example is available pre\-packaged as the explain_setuid_or_die function.

Definition at line 28 of file setuid.c.