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Improved error checking of snprintf #19

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Merged
hjmjohnson merged 1 commit into from
Jan 12, 2026
Merged

Improved error checking of snprintf #19

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21 changes: 12 additions & 9 deletions nifti2/nifti_tool.c
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Original file line number Diff line number Diff line change
Expand Up @@ -852,40 +852,43 @@ int verify_opts( nt_opts * opts, const char * prog )
int fill_cmd_string( nt_opts * opts, int argc, const char * argv[])
{
char * cp;
size_t len, c, remain = sizeof(opts->command); /* max command len */
int ac;
size_t remain = sizeof(opts->command); /* max command len */
int has_space; /* arguments containing space must be quoted */
int skip = 0; /* counter to skip some of the arguments */

/* get the first argument separately */
len = snprintf( opts->command, sizeof(opts->command),
"\n command: %s", argv[0] );
if( len >= sizeof(opts->command) ) {
int len = snprintf( opts->command, sizeof(opts->command),
"\n command: %s", argv[0] );
if( len < 0 || (size_t)len >= sizeof(opts->command) ) {
fprintf(stderr,"FCS: no space remaining for command, continuing...\n");
return 1;
}
cp = opts->command + len;
remain -= len;

/* get the rest, with special attention to input files */
for( ac = 1; ac < argc; ac++ )
for( int ac = 1; ac < argc; ac++ )
{
if( skip ){ skip--; continue; } /* then skip these arguments */

len = strlen(argv[ac]);
if( len + 3 >= remain ) { /* extra 3 for space and possible '' */
size_t tmp_len = strlen(argv[ac]);
if( tmp_len + 3 >= remain ) { /* extra 3 for space and possible '' */
fprintf(stderr,"FCS: no space remaining for command, continuing...\n");
return 1;
}

/* put the argument in, possibly with '' */

has_space = 0;
for( c = 0; c < len-1; c++ )
for( size_t c = 0; c < tmp_len-1; c++ )
if( isspace(argv[ac][c]) ){ has_space = 1; break; }
if( has_space ) len = snprintf(cp, remain, " '%s'", argv[ac]);
else len = snprintf(cp, remain, " %s", argv[ac]);

if( len < 0 || len >= remain ) {
fprintf(stderr,"FCS: error parsing command, continuing...\n");
return 1;
}
remain -= len;

/* infiles is okay, but after the *next* argument, we may skip files */
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21 changes: 12 additions & 9 deletions niftilib/nifti1_tool.c
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Original file line number Diff line number Diff line change
Expand Up @@ -690,40 +690,43 @@ int verify_opts( nt_opts * opts, const char * prog )
int fill_cmd_string( nt_opts * opts, int argc, const char * argv[])
{
char * cp;
size_t len, c, remain = sizeof(opts->command); /* max command len */
int ac;
size_t remain = sizeof(opts->command); /* max command len */
int has_space; /* arguments containing space must be quoted */
int skip = 0; /* counter to skip some of the arguments */

/* get the first argument separately */
len = snprintf( opts->command, sizeof(opts->command),
"\n command: %s", argv[0] );
if( len >= sizeof(opts->command) ) {
int len = snprintf( opts->command, sizeof(opts->command),
"\n command: %s", argv[0] );
if( len < 0 || (size_t)len >= sizeof(opts->command) ) {
fprintf(stderr,"FCS: no space remaining for command, continuing...\n");
return 1;
}
cp = opts->command + len;
remain -= len;

/* get the rest, with special attention to input files */
for( ac = 1; ac < argc; ac++ )
for( int ac = 1; ac < argc; ac++ )
{
if( skip ){ skip--; continue; } /* then skip these arguments */

len = strlen(argv[ac]);
if( len + 3 >= remain ) { /* extra 3 for space and possible '' */
size_t tmp_len = strlen(argv[ac]);
if( tmp_len + 3 >= remain ) { /* extra 3 for space and possible '' */
fprintf(stderr,"FCS: no space remaining for command, continuing...\n");
return 1;
}

/* put the argument in, possibly with '' */

has_space = 0;
for( c = 0; c < len-1; c++ )
for( size_t c = 0; c < tmp_len-1; c++ )
if( isspace(argv[ac][c]) ){ has_space = 1; break; }
if( has_space ) len = snprintf(cp, remain, " '%s'", argv[ac]);
else len = snprintf(cp, remain, " %s", argv[ac]);

if( len < 0 || len >= remain ) {
fprintf(stderr,"FCS: error parsing command, continuing...\n");
return 1;
}
remain -= len;

/* infiles is okay, but after the *next* argument, we may skip files */
Expand Down