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Use stpeprintf() where appropriate

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This function allows reducing error checking (since errors are
propagated across chained calls), and also simplifies the calculation of
the start and end of the buffer where the string should be written.

Moreover, the new code is more optimized, since many calls to strlen(3)
have been removed.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
This commit is contained in:
Alejandro Colomar
2023-01-30 00:54:07 +01:00
committed by Iker Pedrosa
parent 7e213cfb50
commit 46610792e9
2 changed files with 40 additions and 38 deletions
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22
libmisc/idmapping.c
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@@ -12,6 +12,7 @@
#include <stdlib.h>
#include <stdio.h>
#include "prototypes.h"
#include "stpeprintf.h"
#include "idmapping.h"
#if HAVE_SYS_CAPABILITY_H
#include <sys/prctl.h>
@@ -141,7 +142,7 @@ void write_mapping(int proc_dir_fd, int ranges, const struct map_range *mappings
int idx;
const struct map_range *mapping;
size_t bufsize;
char *buf, *pos;
char *buf, *pos, *end;
int fd;
#if HAVE_SYS_CAPABILITY_H
@@ -189,21 +190,20 @@ void write_mapping(int proc_dir_fd, int ranges, const struct map_range *mappings
bufsize = ranges * ((ULONG_DIGITS + 1) * 3);
pos = buf = xmalloc(bufsize);
end = buf + bufsize;
/* Build the mapping command */
mapping = mappings;
for (idx = 0; idx < ranges; idx++, mapping++) {
/* Append this range to the string that will be written */
int written = snprintf(pos, bufsize - (pos - buf),
"%lu %lu %lu\n",
mapping->upper,
mapping->lower,
mapping->count);
if ((written <= 0) || ((size_t)written >= (bufsize - (pos - buf)))) {
fprintf(log_get_logfd(), _("%s: snprintf failed!\n"), log_get_progname());
exit(EXIT_FAILURE);
}
pos += written;
pos = stpeprintf(pos, end, "%lu %lu %lu\n",
mapping->upper,
mapping->lower,
mapping->count);
}
if (pos == end || pos == NULL) {
fprintf(log_get_logfd(), _("%s: stpeprintf failed!\n"), log_get_progname());
exit(EXIT_FAILURE);
}
/* Write the mapping to the mapping file */