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POfree(): invalid next size (fast) string too long?
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copied!<p>My code is getting the following error:</p> <pre><code>free(): invalid next size (fast) </code></pre> <p>My code:</p> <pre><code> #include <stdio.h> #include <string.h> #include <stdlib.h> int main() { char *temp_str; char *pos, *pos2; char *key = (char*)malloc(20); char *data = (char*)malloc(20); const char newline = '\n'; char *unparsed_data = "NEW_DATA_PACKET\n\ Data Set 16-byte Universal Key\n\ Unix Time Stamp (microsecs): 1319639501097446\n\ Frame Number: 0\n\ Version: 3\n\ Platform Yaw Angle (deg): 15.22428\n\ Platform Pitch Angle (deg): 1.78528\n\ Platform Roll Angle (deg): 2.004111\n\ Image Source Source: test\n\ Image Coordinate System: Testing XXXXX\n\ Sample Latitude (deg): 17.306791\n\ Sample Longitude (deg): -60.26209\n\ Sample True Altitude (m): 7.623407\n\ Sample Horizontal FoV (deg): 0.1821277\n\ Sample Vertical FoV (deg): 15.1879\n\ Sample Rel. Azimuth Angle (deg): 291.70295\n\ Sample Rel. Elevation Angle (deg): -5.941163\n\ Sample Rel. Roll Angle (deg): 3.10959\n\ Checksum: 4659\n"; temp_str = (char*)malloc(strlen(unparsed_data)); printf("\nThe original string is: \n%s\n",unparsed_data); //Ignore the first two lines pos = strchr(unparsed_data, newline); strcpy(temp_str, pos+1); pos = strchr(temp_str, newline); strcpy(temp_str, pos+1); printf("STARTING THE PARSER\n\n"); while(strlen(temp_str) > 2) { printf("\tstarting loop\n"); //Getting the position of the colon and newline character pos = strchr(temp_str, ':'); // ':' divides the name from the value pos2 = strchr(temp_str, '\n'); //end of the line realloc(key, (pos-temp_str-1)); //allocate enough memory realloc(data, (pos2-pos)-1); printf("After realloc \n"); //copying into key and data strncpy(key, temp_str, (pos-temp_str)); strncpy(data, pos + 2, (pos2-pos)-2); //Append null terminator strcpy(key+(pos-temp_str-1)+1, ""); strcpy(data+(pos2-pos)-2, ""); printf("%s = ",key); printf("%s\n",data); assign_value(key,data, &gvals); printf("The value has been assigned\n"); strcpy(temp_str, pos2+1); printf("Freeing key and data\n\n"); free(key); free(data); } return 0; } </code></pre> <p>I am also getting some garbage when it is printing</p> <pre><code>STARTING THE PARSER starting loop After realloc Unix Time Stamp (m13196395 = 13196395 The value has been assigned Freeing key and data *** glibc detected *** ./memory_alloc: free(): invalid next size (fast): 0x098cd008 *** </code></pre> <p>Finally, when I reduce the length of the lines of the string, the code works perfectly. It works fine with the following string:</p> <pre><code>char *unparsed_data = "NEW_DATA_PACKET\n\ Data Set 16-byte Universal Key\n\ Time Stamp: 1319639501097446\n\ Frame Number: 0\n\ Version: 3\n\ Yaw Angle: 15.22428\n\ Pitch Angle: 0.78528\n\ Roll Angle: 2.004111\n\ Source: test\n\ Coor System: Test XXXXX\n\ Latitude: 27.306791\n\ Longitude: -60.26209\n\ True Altitude: 7.623407\n\ Hor FoV: 0.1821277\n\ Ver FoV: 15.1879\n\ Azimuth: 291.702954\n\ Elevation: -0.433563\n\ Roll: 0.79659\n\ Checksum: 2659\n"; </code></pre> <p>** <strong>*<em>Solution:</em>*</strong> **</p> <pre><code>int main() { char *temp_str; char *pos, *pos2; char *key = (char*)malloc(20); char *data = (char*)malloc(20); const char newline = '\n'; char *unparsed_data = "NEW_DATA_PACKET\n\ The UAS Datalink Local Data Set 16-byte Universal Key\n\ Time Stamp: 1319639501097446\n\ Frame Number: 0\n\ Version: 3\n\ Yaw Angle: 15.22428\n\ Pitch Angle: 0.78528\n\ Roll Angle: 2.004111\n\ Source: test\n\ Coor System: Test XXXXX\n\ Latitude: 27.306791\n\ Longitude: -60.26209\n\ True Altitude: 7.623407\n\ Hor FoV: 0.1821277\n\ Ver FoV: 15.1879\n\ Azimuth: 291.702954\n\ Elevation: -0.433563\n\ Roll: 0.79659\n\ Checksum: 2659\n"; temp_str = (char*)malloc(strlen(unparsed_data)); //Ignore the first two lines pos = strchr(unparsed_data, newline); strcpy(temp_str, pos+1); pos = strchr(temp_str, newline); strcpy(temp_str, pos+1); printf("STARTING THE PARSER\n\n"); while(strlen(temp_str) > 2) { printf("\tstarting loop\n"); //Getting the position of the colon and newline character pos = strchr(temp_str, ':'); // ':' divides the name from the value pos2 = strchr(temp_str, '\n'); //end of the line char *new_key = (char*)realloc(key, (pos-temp_str+1)); //allocate enough memory char *new_data = (char*)realloc(data, (pos2-pos+1)); if(new_key) key = new_key; if(new_data) data = new_data; printf("After realloc \n"); //copying into key and data strncpy(key, temp_str, (pos-temp_str)); strncpy(data, pos + 2, (pos2-pos)-2); //Append null terminator memset(key + (pos-temp_str) , '\0', 1); memset(data + (pos2 - pos), '\0', 1); printf("%s = ",key); printf("%s\n",data); assign_value(key,data, &gvals); printf("The value has been assigned\n"); strcpy(temp_str, pos2+1); printf("Freeing key and data\n\n"); free(key); key= NULL; free(data); data = NULL; } return 0; } </code></pre>

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